hc vin qun y

B mn Hi sc cp cu

hi sc cp cu gio trnh ging dy ca hc vin qun y

Nh xut bn qun i nhn dn

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Li gii thiu

huyn ngnh Hi sc cp cu ngy nay v ang pht trin mnh trn th gii cng nh Vit Nam. Nh tin b ca chuyn

ngnh Hi sc cp cu thc y, hu thun cho cc chuyn ngnh ngoi khoa, ni khoa, c hc, truyn nhim, sn khoa, nhi khoa... v chuyn khoa k thut cao nh ghp cc c quan.

B mn Hi sc cp cu - Hc vin Qun y mi thnh lp do vy nhu cu v gio trnh, ti liu tham kho chuyn ngnh l vn mang tnh cp thit.

Gio trnh do TS: Tt Cng ch bin cng gio vin trong B mn Hi sc cp cu - Hc vin Qun y kt hp vi mt s chuyn vin HSCC trong Qun i v b mn HSCC ca trng i hc y khoa - H Ni bin son.

Tp gio trnh Hi sc cp cu gm 6 chng: tun hon - h hp - thn - ni tit - ri lon nc in gii, cn bng kim toan - ng c cp, trong c nhng vn mi nh: hi chng suy h hp cp tin trin (ARDS), ghp thn, tch huyt tng v cht no vv... Cc bi vit u cp nht kin thc mi, c bn v h thng. Gio trnh ny ginh cho sinh vin y khoa, cn b sau i hc, c bit cho bc s chuyn ngnh HSCC hc tp v tham kho.

Xin trn trng gii thiu vi bn c cun gio trnh Hi sc cp cu v mong nhn c kin qu bu ng gp gio trnh tip tc c hon thin.

Chng ti chn thnh cm n cc tc gi cng s hp tc gip ca ban bin tp, nh xut bn, nh in v cc bn ng nghip cun sch n vi bn c.

Gim c Hc Vin Qun Y

Thiu tng GS.TS. Phm Gia Khnh

C

Li ni u

rong nhng thp k qua v c bit nhng nm gn y chuyn ngnh HSCC pht trin mnh m c v phng tin hin i

cng nh k thut chuyn ngnh. Ngoi trung tm Hi sc cp cu chung cn c nhng n v cp cu hi sc chuyn su v mch vnh, h hp, thn kinh s no, ng c vv...

Vai tr ca cp cu l cc k quan trng v tip cn bnh nhn ngay t u vi mi loi tai nn, bnh l cp tnh e do n chc phn sng ca c th. Nu khng cp cu ban u tt th nhiu trng hp t vong trc khi vo vin. Cp cu sm ng k thut, hi sc tt v phi hp vi cc chuyn khoa iu tr ton din s tr li cuc sng v sc kho hon ho cho ngi bnh.

Gio trnh Hi sc cp cu gm 19 bi cp nhng vn thit yu trong cp cu - Hi sc c bn, h thng, hin i cp nht vi nhiu ti liu tham kho t nm 1998 n nm 2001 s gip ch cho sinh vin y khoa v cc cn b sau i hc hc tp v tham kho.

Mc d cc tc gi ht sc c gng, song cun sch khng trnh khi nhng thiu st. Rt mong bn c gp kin gio trnh c b sung v hon chnh trong ln in sau.

Cc tc gi

T

Gio trnh - hi sc cp cu Gio trnh ging dy ca hc vin qun y

Mc lc

Chng I: Tun hon - Hi sinh tim phi no. - Thuc vn mch v cng tim dng trong Hi sc cp cu. - Sc chn thng. - Sc nhim khun. - Cht no.

Chng II: H hp - Suy h hp cp. - Ph phi cp. - Suy h hp cp tin trin (ARDS). - Nhim khun phi ph qun bnh vin trong khoa Hi sc cp cu.

Chng III: Thn - Suy thn cp. - Ghp tng-ghp thn. Theo di v iu tr sau ghp.

Chng IV: Ni tit - Cp cu v iu tr cn nhim c Hormon gip kch pht sau phu thut. - Cp cu v iu tr cn nhc c nng gy suy h hp cp. - Tch huyt tng (Plasmapheresis).

Chng V: Ri lon nc in gii, cn bng kim toan - iu chnh nc - in gii. - Cn bng kim toan.

Chng VI: Ng c cp - Nguyn tc cp cu iu tr ng c cp. - Cp cu iu tr mt s ng c cp thng gp.

Chng VII: Chn thng s no nng - Theo di v iu tr cc bnh nhn chn thng s no. - Ti liu tham kho

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Chng I

Tun hon

hi sinh tim - phi - no (Cardiopulmonary - cerebral resuscitation)

Tt Cng

L Nam Hng

1. i cng. Ngng tim - phi (cardiopulmonary arrest) l hu qu cui cng ca rt nhiu

nguyn nhn v bnh l khc nhau v thng dn n t vong. Ngng tim - phi c th xy ra t ngt mi ni trong v ngoi bnh vin, thm ch ngay trong phng m, phng hi sc.

Cp cu ngng tim - phi phi rt khn trng ng k thut, trch nhim v kin tr vi mt phc ph hp mi c th cu sng bnh nhn. Theo bo co ca hi gy m Th gii (WFSA) nm 1988 th gn 50% bnh nhn ngng tim - phi c cp cu lm cho tim p li song mt na trong s ny cht mc d c a vo bnh vin. S cn li b tn thng no dn ti t vong l t 10 n 30%. Nh vy ch khong di 10% s bnh nhn ngng tim phi c th c cp cu v iu tr thnh cng khi ra vin. Chnh v vy m phi hi sinh tim - phi - no (CPCR) mi c th tr bnh nhn v cuc sng bnh thng c.

Trong nhng nm gn y Hip hi tim mch Hoa K (AHA), Hi hi sc Chu u (ERC)- u ban quc t v hi sinh (ILCOR)- Hi gy m th gii (WFSA) thng nht a ra phc cp cu ngng tim - phi (tp ch gy m th gii s 10-1999) v tp ch quc t v iu tr tch cc nm 1999; 2000 v s ma xun nm 2001 hng dn phc cp cu hi sinh tim - phi - no, lm ti liu c bn cho iu tr v ging dy hin nay: bao gm 3 phn khng th tch ri l:

- Hi sc tim - phi c bn (basic life support): vi 3 bc a-b-c. - H tr cc chc nng sng bng bin php tin tin hay hi sc tim - phi

chuyn su (advanced life support). - Duy tr cc chc nng sng v hi sinh no cng vi iu tr ton din

(prolonged life support).

2 . Nguyn nhn ngng tim - phi. * Nguyn nhn do tim:

- Bnh thiu mu c tim. - Tc mch vnh cp. - Cc bnh c tim. - Vim c tim. - Chn thng tim chn p tim cp. - Kch thch trc tip vo tim. * Nguyn nhn tun hon: - Thiu khi lng tun hon cp. - Tc mch phi (do kh, do cc nghn). - C ch phn x dy ph v. * Nguyn nhn h hp: - Trn kh mng phi nng. - Thiu oxy cp (thng gy ra v tm thu): d vt, tc ng th. - u thn. * Nguyn nhn ri lon chuyn ho: - Ri lon chuyn ho kali. - Tng canxi mu cp. - Tng catecholamin cp. - H thn nhit. * Nguyn nhn do thuc, nhim c: - Tc ng trc tip ca thuc gy ngng tim. - Do tc dng ph ca thuc. * Nguyn nhn khc: - in git. - ui nc. 3. hi sinh tim - phi - no:

3.1. Hi sc tim phi c bn:

Mc ch: L nhanh chng phc hi li tun hon v h hp hu hiu chng li qu trnh bnh l c bn thiu oxy, bo v no, ng thi pht hin v gii quyt nguyn nhn gy ra ngng tim - phi.

Phng php hi sc tim - phi c bn, mc d c mt s thay i theo tng nc, song n c chun ho v c ging dy ph cp cho cc nhn vin cp cu cng nh cho cng ng.

Cc ng tc cp cu c bn nhm mc ch duy tr s thng sut ca ng th, bo m thng kh phi v tun hon c hiu qu m khng cn n nhng phng tin no, hoc ch cn 1 canule ming hng hoc 1 mt n (masque) n gin.

3.1.1. Chn on ngng tim - phi:

Chn on xc nh ngng tim - phi khi khng bt c mch cnh (hoc mch bn), mt thc, ngng th hoc th ngp; da xm, tm ti, mu khng chy hoc mu en trn vt m l cc bin php b xung, khng dng ng nghe tim xc nh ngng tim phi v mt thi gian v kh xc nh.

Gi cp cu: gi to ngi n h tr v gi i cp cu cng nhanh cng tt.

3.1.2. K thut thc hin cc ng tc cp cu c bn: t bnh nhn nm nga trn nn cng. C 3 ng tc phi lm: A (Airway: ng th), B (Breathing: h hp), C

(Circulation: tun hon). Cc ng tc ny c ni n t 30 nm nay trong cc khuyn co ca Hi tim mch Hoa K.

3.1.2.1. Gii phng ng th: Nga nh u, y xng hm di ra trc v nng cm bnh nhn ln. Nu

nghi ng c chn thng ct sng c th ko hm di mt cch thn trng trnh lm tng thng tn tu c.

3.1.2.2. Thng kh: Thi ming - ming hoc ming - mi hoc bp bng qua mt n (masque). Thi chm trong 1,5 - 2 giy, sau ch 3 - 4 giy cho khng kh thot ra

hon ton trc khi thi tip trnh hi vo lm cng d dy. Trong khi thi tm ngng p tim ngoi lng ngc. Th tch mi ln thi l 800 - 1200ml ngi ln (10 - 15ml/kg). Cho n nay khng c bng chng no cho thy HIV c th ly qua nc bt

n thun. Tuy nhin s ly lan cc bnh khc c th xy ra nn c th dng cc phng tin bo v (sng hoc masque dng 1 ln) tuy nhin khi dng cc phng tin ny th hiu qu ca thng kh nhn to c th b gim i.

3.1.2.3. Tun hon (circulation): p tim ngoi lng ngc vi mt tn s nhanh 80 - 100l/pht v s tng quan

gia p v gin l 50%. im p c xc nh l 1/3 di chnh gia xng c, lc p mnh lm xng c ln xung l tng l 3 - 5 cm. Khi ngng tim - phi do rung tht xy ra v khng c sn my ph rung, ngi ta c th th thay th bng bin php c in "m vo xng c" nhng hiu qu l rt hn ch.

Nu ch c mt ngi thc hin vic cp cu hi sinh th nn thc hin 15 ln p tim, ri dng li thi chm 2 - 3 ln. Cn khi c hai ngi th c 5 ln p tim 1 ln thi ngt. cn nh k kim tra tnh hiu qu ca ng tc cp cu v mc thit lp li tun hon ca bnh nhn c 2 - 3 pht/ln. Trong trng hp c tc nghn c hc hon ton ng th do d vt ri vo kh o trn, phi thc hin nghim php Heimlich.

* Sinh l hc ca vic p tim ngoi lng ngc:

Tun hon ca mu trong c th bnh nhn khi hi sinh tim - phi ch yu c gii thch bi 2 thuyt, i din cho 2 cch nhn nhn khc nhau v tc dng ca lc p trc tip ln lng ngc.

+ Thuyt bm tim: y l thuyt kinh in, c nu ra t nm 1960 bi Kowenhoven. Theo

thuyt ny, sc p trc tip ln tim gia ct sng v xng c s to ra tun hon mu trong c th, ngha l khi p tim, cc van tim s ng li, cn trong th tm trng nh lng ngc gin ra th ng lm tim cng gin v cc van 2 l v 3 l t ng m ra nh bnh thng.

Trong nhiu nm, vic gii thch ny c coi l tho ng, nhng nhng nghin cu v siu m tim hoc l quay phim ng mch ngi ta thy cc van tim khng cn hot ng hiu lc trong p tim ngoi lng ngc. Vic ng m ca n khng cn u n v ng nhp vi p tim. Do vy kt qu ca tun hon mu trong p tim ngoi lng ngc cn ph thuc vo nhiu yu t khc na.

+ Thuyt bm lng ngc: Thuyt ny ngi ta khng tha nhn sc p trc tip ln tim l tc nhn ch

yu to nn tun hon mu, m c ch chnh l do thay i p lc trong lng ngc. Tim v cc mch mu ca phi trong khi p c vai tr nh mt ng dn th ng, ton b th tch tim v cc mch mu phi to nn mt b cha mu. Khi p tim th p lc trong lng ngc tng lm dn p mu chuyn ng xui chiu trong h thng ng dn th ng . Mu khng th pht ngc vo cc tnh mch ln c l do c cc van tnh mch sinh l ca tnh mch ch trn v tnh mch ch di. T rt nhiu nhn xt thc nghim v lm sng khng nh l thuyt ny v t gia nhng nm 80 ca th k 20 n c mi ngi chp nhn.

+ B sung c 2 l thuyt trn: Thuyt v bm tim v bm lng ngc dng nh l tri ngc nhng li b

sung cho nhau. Nhiu cng trnh thc nghim ch ra rng, khi thc hin hi sinh tim phi s c mt hoc nhiu c ch cng tham gia. Trn m hnh thc nghim ngng tim ln, ngi ta thy nu tng lc p th c ch p trc tip ln tim cng tr nn r rng hn. Ngc li khi s dng lc p thp th tun hon ch yu da vo c ch bm lng ngc. Halperin v cng s s dng siu m tim trn ch cho thy nh hng ca chu k h hp ln hot ng ca van hai l, nu lc p ng vo cui th th ra van 2 l s ng v ngc li n m khi p tim ng th ht vo. Paradis v cng s o chnh lch p lc gia cc bung tim, ng mch cnh gc v ng mch cnh trong, trong qu trnh hi sinh tng hp ko di. Cc ng nhn thy rng: ch yu c ch bm lng ngc to nn dng mu tun hon trong cc mch mu, ngoi ra lc p trc tip vo tim cng kt hp to nn tun hon mu. iu ny minh ha rt tt cho kh nng phi hp ca 2 l thuyt trn trong thc hnh lm sng p tim ngoi lng ngc.

* Hiu qu ca p tim ngoi lng ngc: Hiu qu ca p tim ngoi lng ngc thng l rt hn ch so vi lu lng

tim ca tun hon t nhin. Theo cc m hnh thc nghim trn ng vt hoc

nghin cu ngi th hiu qu huyt ng khi p tim ngoi lng ngc l rt thay i. p tim ngoi lng ngc rt ng cng ch t 20 - 30% lu lng bnh thng ca tim, do gim rt nghim trng tun hon cc c quan, c bit l tun hon vnh (y l iu ct yu to nn s hi phc ca hot ng tim) hoc l tun hon no (iu quyt nh c bn cho tin lng v thn kinh). nh ca p lc ng mch khi p tim ngoi lng ngc him khi vt qu 70mmHg. Nh vy tun hon ca p tim ngoi lng ngc l khng , mong manh v khng th snh c vi b p c hiu qu ca tun hon t nhin. Da trn cc l lun ny c rt nhiu ci tin k thut c xut nhm ci thin hiu lc ca hi sinh tim - phi.

* Cc th nghim ca p tim ngoi lng ngc: + Tng lc v tn s p tim chun: Trn thc nghim, lu lng tim c ci thin bi s tng lc p. ngi lc

p tt nht l lm lng ngc ln xung c t 4 - 5 cm. Ngc li tc dng ca tng tn s p tim th t hiu qu hn: tn s trn 120l/pht khng lm ci thin lu lng tim. Ni chung tn s p c quy nh khong 80 - 100l/pht s m bo lu lng tim tt nht v cho 2 t l cn xng gia thi gian p v gin l khong 50%.

+ p tim bng dng c: c gng ci thin k thut v tn s u n ca p tim ngoi lng ngc,

ngi ta ch ra nhiu thit b p tim. Ni ting nht l Thumper c cu to vi 1 piston hi do p lc ca bnh oxy cung cp. Lc p v nng lng ngc c to ra nh piston v c th iu chnh ln ca piston ny d dng. My c ci t chng trnh c 5 ln p s c thi gian tng xng cho 2 ln thi vo chm ca my th. Tn s p 80 - 90l/pht. Mc d vy hiu qu lm sng ca kiu my ny ch t c i vi mt vi loi bnh nhn. My t ra rt hu ch cho nhng trng hp phi hi sinh tim phi ko di v trong cc m hnh thc nghim.

+ p tim v thi ng nhp: K thut c a ra sau nhng nm 1980, ngi ta tin hnh thi kh vo

trong phi cng lc vi p lng ngc, bng cch lm tng p lc trong lng ngc. Thc nghim trn ng vt cho thy k thut ny lm tng lu lng mu no. Trn lm sng, k thut ny i hi bnh nhn phi c t ni kh qun (NKQ) v thng kh phi nhn to bng my. Tuy nhin theo Kirsher khi p dng phng thc ny cho nhng bnh nhn c hi sinh ngoi bnh vin khng thy c ci thin thi gian sng d. Trn thc t n l c s ngi ta chp nhn hin tng khng ng nhp gia my th v p tim ngoi lng ngc.

+ p bng ngt qung: K thut ny p bng phi hp khi gin lng ngc trong p tim ngoi lng

ngc nhm mc ch lm tng dng mu tnh mch tr v v cng lc lm tng p lc quai ng mch ch, u tin tun hon khu vc na trn ca c th. p bng ngt qung c p dng trn ngi bi Sack v cng s trong cc trng hp hi sc ngng tim t ngt bnh vin. Cc tc gi thy s ci thin ng k tin lng ca bnh nhn. Tuy nhin phi ghi nhn rng, trn lm

sng k thut ny kh thc hin bi v n cn t nht l 3 ngi cp cu v phi phi hp ht sc hi ho. N bt buc cc bnh nhn phi c t NKQ v thng kh nhn to trnh nguy c ht vo ph qun cc cht nn tro ngc.

- p v nng tch cc: l th nghim mi nht ci thin p tim ngoi lng ngc, n s dng

mt gic ht c t trn ngc p tim ngoi lng ngc. N cho php sau khi p ngi cp cu s ko gic ht nng ch ng lng ngc nn nhn ln. Th nng tch cc ny tng ng vi th tm trng ca tim, do lm tng y mu vo cc bung tht nh tng dng mu tnh mch tr v v lm tng lu lng tim ln p tip theo. Cohen v cng s quan st cc bnh nhn ngng tim - phi ko di bng siu m v thy c tng lu lng tim, tng kch thc cc bung tht v nh phi trong th nng tch cc lng ngc. Vic tng lu lng tim ny i km vi tng ng k p lc ng mch ngoi vi. Cc kt qu thc nghim tng t ch cho thy phng php ny cn gy tng hiu qu thng kh do c ng tch cc lng ngc th gin th ng. Tuy nhin, trc khi ph bin vic s dng k thut ny cn c cc kt qu thm d v ci thin t l cu sng cng nh tc dng trn tun hon ngoi vi, no v c tim. i vi ngi gy th khng thc hin c v khng gn c gic ht.

+ o hi sinh tim phi: l mt loi o hi c bm phng ngt qung tng hi,nh vy s to ra

hin tng tng ngt qung p lc trong lng ngc, nh p lc ca quai ng mch ch v p lc ti mu mch vnh s cao hn so vi p tim ngoi lng ngc. K thut ny c thc hin trn ng vt t nhiu nm nhng cha c p dng rng ri trn ngi, hiu qu ca n i vi kh nng cu sng bnh nhn phi tip tc c xc nh.

3.1.2.4. Bp tim trong lng ngc: Bp tim trong lng ngc lm tng t l cu sng vi chc nng no tt hn,

nht l trong phng m, trong bnh vin, thm ch bp tim trc tip ti 2,5 gi sau ngng tim m vn cu sng c bnh nhn. Bp tim trc tip lm tng p lc ti mu no v tun hon vnh hn so vi p tim ngoi lng ngc. V th d lm cho tim p li nhanh hn v cho php quan st trc tip tnh trng tim, d cho thuc, dch truyn v c th lm sc in trc tip. Ngoi ra m ngc p tim cn cho php cm mu trong ngc, kp mch mu tm thi khi cp cu, trong cc trng hp ngng tim - phi do tn thng cc mch mu ln.

* Ch nh: Ngng tun hon trong bi cnh:4 - m ngc sn trong khi m. - Nghi ng chy mu trong lng ngc. - Chy mu ln trong bng cn phi m ngc cp ng mch ch ngc

thp v bp tim. - Tc mch phi ln . - Ngng tim do h thn nhit (m ngc cho php lm m tim trc tip).

- Khng th p tim ngoi lng ngc (bin dng lng ngc hoc kh ph thng nng).

- p tim ngoi lng ngc 5-10 pht m khng kt qu th tu theo kinh nghim v iu kin ca tng ni, tng thy thuc m quyt nh cho hp l.

* K thut: t NKQ th my p lc dng ngt qung (IPPV) hoc vi PEEP (p lc

dng cui th th ra). Rch da khoang lin sn 4 hoc 5 bn tri, ct c lin sn bng ko Mayor (trnh b mch thn kinh lin sn), m rng lin sn. Bp tim ngay khng cn m mng ngoi tim, bp khong 1ln/giy. Ngi thy thuc ng bn tri bnh nhn, t bn tay bn tri pha sau tht tri, tay kia pha trc tht phi, trong khi bp tim trnh bp tm nh, nu khng nhn r tm tht th c th m mng ngoi tim bp, c th tim trc tip adrenalin vo bung tht tri, nu cn c th kh rung tht bng 2 in cc trong qua gc tm HTM 9%0, (1cc t sau tim ngay tht tri v in cc kia t tht phi), sc in bt u bng 0,5 J/kg (cng c th nh sc ngoi lng ngc khi m lng ngc). Trong trng hp tc mch phi th m ngc bp tim c th lm thot c cc nghn.

3.2. Hi sc tim - phi chuyn su:

Mc ch l thit lp trong khong thi gian ngn nht tun hon t nhin c hiu qu, khc phc ti a hu qu thiu oxy ca tim, no. Khc vi hi sc tim phi c bn, hi sc tim - phi chuyn su ch c thc hin vi kp hi sc c o to chuyn khoa v s dng tt cc k thut hi sc hin i. N gii quyt tt nht mi lin quan cht ch ph thuc ln nhau gia h hp v tun hon. Sau y l cc k thut u tay v c xp di dng cng thc thc hnh.

3.2.1. Ph rung tht sm: Cn ghi in tim 1 o trnh bit ngng tun hon trng thi v tm thu,

rung tht hay l phn ly in c. Rung tht l ngun gc ca a s cc trng hp ngng tim - phi t ngt

ngoi bnh vin ngi ln, cho nn ph rung tht l vic lm u tin v c hiu qu nht ca hi sc tim - phi chuyn su. Vic u tin ph rung tht sm s ci thin quan trng tin lng cp cu, do hin nay cc nhn vin cp cu hi sc c trang b my ph rung bn t ng.

Mc ch ca vic ph rung l kh cc mt lng ng k cc t bo c tim cho php lp li mt hot ng in phi hp ng b ca c tim. Nu s dng mt nng lng qu thp s khng t hiu qu v ngc li, mt nng lng qu mnh c th lm tn thng c tim cng nh l lm mt c may c th hi phc tr li hot ng ca tim. V th nn bt u ph rung vi mt ngun in nng tng i thp ri tng dn. Bt u t 200J ri nhc li mt ln 200J na, nu khng kt qu tip tc tng ln 300J ri 360J. Mun t c hiu lc ph rung phi thc hin k thut chun xc. Hai bn in cc phi c t ng:

thng thng l di n phi v nch tri hoc vng mm tim. Kch thc in cc phi ln t 8 - 12cm2 v c ph mt lp kem dn in, phi p cht din in cc vo mt da ca bnh nhn khi nh sc. Nu cc iu kin ny khng c tn trng th in tr lng ngc s tng ln ng k lm gim hiu qu iu tr ca sc in v gy bng da ti ch. Khi nh sc phi tho dy in tim t bnh nhn ni vi my. m bo an ton, ngi nh sc phi i gng cch in v ng trn bc g v khng chm vo ging bnh nhn. 3.2.2. t ni kh qun:

t ni kh qun l phng php kim sot ng th hu hiu nht trong cp cu ngng tim - phi. N cho php va bo v ng th va h hp nhn to vi mt nng oxy cao. C th dng ng ni kh qun cho adrenaline trong trng hp khn cp cng c th dng masque thanh qun thng kh nhn to nu ngi cp cu khng quen t NKQ hoc khng c dng c.

3.2.3. Thng kh nhn to: C th thng kh nhn to bng 1 bng cao su ni vi ni kh qun hoc bng

my th t ng. Nu dng my th th chnh tn s th 12 ln/pht v th tch lu thng 10ml/kg. Nu bnh nhn c ng NKQ th khng bt buc phi xen k p tim ngoi lng ngc vi th my th bm kh vo.

3.2.4. Dng thuc cp cu: 3.2.4.1. Adrenaline: Adrenaline l thuc c bn ca hi sc chuyn su, ch yu l nh tc dng

. adrenergic khi phc kh nng co bp ca c tim, do ci thin tnh hiu qu ca p tim ngoi lng ngc. N lm tng p lc tin tm trng quai ng mch ch, l yu t quyt nh n tun hon vnh. Adrenalin lm ci thin lu lng mu no bng phn phi dng mu ng mch cnh gc u tin cho ng mch cnh trong. Nh vy, ch n gin p tim ngoi lng ngc tt kt hp vi tim adrenaline s c hiu qu hn so vi cc k thut phc tp khc nu trn. Kinh in, vi ngi ln liu adrenaline l 1mg nhc li c 3pht/ln. Gn y, mt vi cng trnh ngh s dng liu adrenaline cao hn. Brunette v cng s tin hnh thc nghim trn ch kt lun rng, dng liu ln adrenaline ngay t u cho php lp li tun hon t nhin nhanh hn, huyt ng tt hn v thi gian sng d cao hn. Gonzalez v cng s s dng liu cao adrenaline trong cp cu ngng tim - phi khng cn p ng vi cc iu tr thng thng ngoi bnh vin, thy c tng p lc ng mch ng k khi p tim ngoi lng ngc vi liu adrenaline 5mg tnh mch.

Do vy hng dn hin nay (nm 2000) ca Hi tim mch M v Hi hi sc Chu u l dng liu u tin 1mg, c sau 3-5 pht nhc li 3 ln m khng hiu qu c th dng liu 3mg/1ln v cng nhc li sau 3 pht.

ng dng: ng tnh mch l ng c chn la u tin. Nu bnh nhn c sn 1 ng tnh mch trung tm th dng ng ny v thuc s vo

tun hon nhanh nht. Nu khng c sn ng tnh mch trung tm th nn t mt ng tnh mch ngoi vi, v s nhanh hn v t nguy him hn (adrenalin liu 1mg hoc 3mg pha long trong 20ml huyt thanh mn 9%o tim tnh mch, trong khi tim cn nng cao chi th ni tim thuc ln v cho dch chy nhanh ln nu tim qua dy truyn dch t sn y nhanh thuc v tun hon chung). C th dng ng ni kh qun nu khng t ng truyn tnh mch c ngay. Khi phi dng liu cao hn gp 2 ln liu tim tnh mch, pha vo 5ml NaCl 0,9%. Sau khi bm thuc vo ng NKQ phi bp bng 2 nhp y thuc vo su. C th bm thuc qua 1 dy ht a qua ng NKQ n tn ch chia 2 ph qun gc. Nng nh adrenaline trong mu khi dng ng ni kh qun thp hn, chm hn v ko di hn so vi dng ng tnh mch. V th khng nn bm vo ng ni kh qan lp li nhiu ln. Vn cn nhiu iu bn ci v hiu qu ca adrenaline bm vo ng ni kh qun v nng adrenaline ngm vo trong mu khng n nh v c th rt thp.

Cc thuc vn mch khc: hin nay khng c mt lun c no ng h vic thay th adrenaline bng 1 thuc vn mch khc. Cc thuc co mch c tnh kch thch alpha n thun (nor adrenaline) khng cho kt qu tt hn adrenaline trong cc nghin cu lm sng. Trong iu tr v tm thu ngi ta cng khng dng isoprnaline v l 1 thuc c kch thch beta n thun.

3.2.4.2. Cc thuc kim ho: Vn s dng cc thuc kim ho trong cp cu ngng tim - phi cn

nhiu quan im tri ngc. Hin nay cc xt nghim phn tch cn bng axit - baz rt hon thin, cho bit tnh trng cn bng axit - baz trong iu kin tun hon bnh thng, nhng n s khng phn nh ng cn bng axit - baz ca t chc v nht l trong t bo khi c ngng tun hon. Ngi ta thy rng trong khi cc kh mu ng mch l bnh thng hoc thm ch th hin mt nhim kim h hp th c th vn tn ti mt nhim toan vi trng thi u thn mnh trong mu tnh mch. iu ny c gii thch bi tch t CO2 trong cc m ngoi vi m nguyn do l lu lng tim gim, lm mu khng th vn chuyn CO2 v tun hon phi, kt qu l nhim toan h hp hoc hn hp. Nhim toan t chc, c bit l c tim cn cao hn so vi toan mu tnh mch o c. Vic iu chnh tnh trng nhim toan ny bng bicacbonat l khng c c s sinh l bnh chc chn m ch khi tun hon mu hu hiu c khi phc to iu kin o thi nhanh v nhiu CO2 th cn bng axit - baz s c b p n nh. Nhim toan mt mc nht nh cha phi l c hi lm ti c th v cha cn can thip hi sc. N khng lm thay i tin lng sng v cng khng cn tr vic ph rung tht thnh cng hoc nh hng n hot tnh ca adrenaline. Ngc li, qu ti bicacbonat c nhiu nguy him hn (v nhim kim lm chuyn dch ng cong phn ly oxyhemoglobin dn ti nhim toan ni bo, nht l trong t bo no v c tim, gy ra tng thm thu v tng Natri mu v cui cng lm bt hot adrenaline) v vy khng nn iu chnh qu mc tnh trng nhim toan trong ngng tim - phi.

Cc thuc kim ho khc nh THAM (tri - hydroxymethyl - aminomethane), carbicarb hoc tribonate c sn sinh hoc khng sn sinh CO2, khng c u chung hn bicacbonat c trong thc nghim cng nh trn lm sng.

Hi hi sc cp cu Chu u chp nhn mt quan im d dt sau: khi khng c bng chng v mt nhim toan r rng tn ti trc lc ngng tim - phi th khng cn s dng bicacbonat, cn trong trng hp ngng tim ko di qu 15 pht hoc khi phn tch kh mu ng mch v tnh mch thy r mt pH mu ng mch thp hn 7,1 v BE < -10, th ch nh dng liu bicacbonat (50ml 8,4%) nhng khng vt qu 1mEq/kg v nhc li 1/2 liu trn sau 10 pht trong sut thi gian hi sinh tng hp. Liu cao hn, ngc li khng c hiu qu v cn nguy him. Cc thuc kim ho c dng tt nht l sau khi tim t p li v iu chnh theo xt nghim cn bng axt - baz.

3.2.4.3. Thuc chng lon nhp: Cc thuc chng lon nhp dng iu tr rung tht khng sc in khng phi

bao gi cng hu hiu v khng phi l khng c tc dng ph. Lidocaine l thuc thng c dng v n lm tng ngng ph rung nhng

hiu qu ca n cha hon ton c chng minh. Sau khi ph rung tht bi v dng adrenaline, dng lidocaine 1,5mg/kg tim tnh mch v c th tim nhc li nu cn, sau duy tr gi git tnh mch liu 4 mg/1pht trong 30 pht sau gim xung 2 mg/1pht trong 2 gi ri 1 mg/1pht tip theo.

Brtylium tosylate (brtylate) liu 5mg/kg tim tnh mch ch nh trong trng hp tht bi vi lidocaine, nhng hiu qu ca n cng cha c chng minh v thuc ny c nhiu tc dng ph ng k trn huyt ng.

3.2.4.4. Atropin: L thuc c hiu lc trong trng hp v tm thu hoc nhp rt chm (dng

phi hp vi adrenaline), liu dng l 1 - 3mg tim tnh mch (tng liu l 0,05mg/kg).

3.2.4.5. Calcium: Dng calcium l v ch v thm ch c hi; ch dng khi c gim calcium

mu trc hoc ng c thuc i khng calcium hoc c tng kali mu > 6 mmol/l th cho 10 ml canxiclorua 10% tim chm tnh mch.

3.2.4.6. Magnesium sulphat: Ch s dng khi h kali mu v cho10 ml dung dch magnesium sulphat 50%

tim chm tnh mch. 3.2.4.7. Amiodaron (cordaron): L thuc chn knh kali c tc dng chng rung tht, d phng rung tht, v

dng trong khi ngng tim. Dng liu 900 mg amiodaron pha trong 1000 ml HTN 5% gi git tnh mch trung tm trong 24 gi. Trong trng hp khn cp c th dng ngay liu u 300mg tim chm tnh mch ngoi bin trong thi gian t 5 pht n 15 pht v tip theo dng liu nh trn.

3.2.4.8. To nhp tim:

Ch nh ca to nhp tm thi l nhp tim chm khng p ng vi thuc. To nhp tm thi trong khi cp cu v tm thu, d c thc hin tht sm cng khng c hiu qu.

3.2.4.9. Khi phc khi lng tun hon (KLTH): Vic phc hi khi lng tun hon rt cn thit trong trng hp c gim

khi lng tun hon mt cch r rng, nht l ngng tim do gim th tch mu lu thng . Qu ti KLTH khng lm ci thin lu lng tim trong p tim ngoi lng ngc. Vic truyn dch khng hon ton l c hi nhng phi thn trng v chng mc. Dch truyn thng c s dng nht l huyt thanh mn ng trng (hoc ringerlactat), liu truyn va phi < 500ml. Nn trnh dng dung dch glucose nht l glucose u trng v tc dng c hi gy tng ng mu, toan chuyn ho, c th s dng glucose 5% trong cp cu.

3.3. Hi sinh no - duy tr s sng lu di (prolonged life support):

+ Sau ngng tim ko di s xut hin hi chng no sau hi sinh (the cerebral postresuscitation syndrome) gm 8 ri lon cn phi d phng iu tr:

- Thiu nng lng ATP. - Suy yu bm ion ( do ph trong t bo ). - Toan ho t chc . - Gim ti mu (do gim oxy). - Nhim c thn kinh gc t bo. - Cc gc t do tng sinh. - Phn ng ph n t chc . - Ri lon cc c quan ngoi no ( nhim c cc tng do thiu oxy ) . + Cc bc tin hnh nh sau: - Sau khi tim p li cn gi huyt p tng nh sau duy tr huyt p bnh

thng (huyt p trung bnh 90-100mmHg) bng dch truyn, thuc co mch hoc gin mch.

- Thng kh phi nhn to lin tc. - Duy tr CO2 mu bnh thng hoc gim nh (tng thng kh va phi:

PaCO2 = 30-35mmHg). - Cho tng oxy t: PaO2 100mmHg. - Duy tr pH ng mch 7,3 - 7,5 bng NaHCO3. - Bt ng bnh nhn nu giy qu bng diazepam, bacbituric, mocphin. - Chng co git (diazepam, phenytoin). - Duy tr Hematocrite, in gii, ng mu, p lc thm thu bnh thng - Corticoid cho liu thp - Duy tr thn nhit 34-350C ngay sau khi cp cu trong thi gian 12 gi. (H

thn nhit lm gim gc t do, gim nhim c ni sinh, tng d tr ATP, lm cn bng vn chuyn ion qua mng, lm gim tiu th oxy).

- iu tr tch cc cho tt c cc tng khc. - t u t th hi cao, tr mnh thng xuyn. C nhiu bin php iu tr chng li hin tng thiu mu no. ngi,

khng c mt th thuc no c dng trong lc ngng tim phi cho php ci thin tnh trng thn kinh. Cc bacbituric (c bit l penthotal) b loi b t khi cng b cc kt qu ca th nghim hi sc no (Brain Resuscitation Clinical Trial), v khng c s ci thin thi gian sng d.

Mi y cc cht c ch canxi tr thnh mc tiu thc nghim ca nhiu trung tm vi nhng kt qu y ha hn. Nimodipine c s dng trn ngi trong ngng tim phi ngoi bnh vin, cc kt qu s b l kh quan. N ci thin c thi gian sng d ca cc trng hp c rung tht m vic cp cu b mun.

Tun hon ngoi c th (CEC) cng c ngh nhm hn ch tc dng ti qun mu no. Martin v cng s tin hnh CEC trn ch b rung tht v nhn xt nh tun hon ngoi c th, vic ph rung tr nn d dng hn nhiu v tin lng tt hn hn so vi hi sc kinh in. Rt tic vic p dng trn ngi trc mt ch gii hn mt vi trung tm ngoi khoa tim mch.

Phi nh rng ch c tnh khn trng, hiu qu ca hi sc ngng tim phi c bn s m bo tt nht cho tin lng thn kinh. Sau khi lp li tun hon t pht th vic iu tr triu chng s trnh c ph no trm trng. Cn phi n nh huyt ng sm, c bit trnh tt huyt p ng mch (nguyn nhn ch yu gy thiu mu no) cng nh cc hin tng tng ng mu, tng thm thu, tng thn nhit v co git.... l cc ngun gc lm trm trng thm cc tn thng thn kinh ca no.

3.4. Theo di trong cp cu ngng tim phi:

3.4.1. Theo di trong khoa hi sc hoc phng m: 1 bnh nhn ang c theo di bng phng php xm nhp (invasive)

c th da vo huyt p do trc tip trong ng mch nh gi hiu qu ca ETNLN. Tuy nhin, huyt p ch l 1 trong cc thnh phn xc nh p lc ti mu mch vnh. Ti mu vnh l ch s quyt nh tin lng v hiu qu ca hi sc.

3.4.2. Theo di khoa khng chuyn su hoc ngoi bnh vin:

Nu ngng tim xy ra 1 ngi khng c theo di, v d ngoi bnh vin cn nh gi cc d kin n gin bng phng php khng xm nhp (non - invasive). l s mch trong khi p tim ngoi lng ngc (ETNLN), quan st trng thi bnh nhn v o in tim cng sm cng tt. o CO2 trong kh th ra (capnomtrie) l phng tin theo di b sung duy nht hu ch trong trng hp ny. Do CO2 ng m v h tnh mch trong lc ngng tim, khi tim p li s

c hin tng tng thi CO2 lng ln. Trong khi cp cu ngng tun hon lng CO2 th ra gip nh gi hiu qu ca ETNLN. Trong trng hp ny o CO2 cui th th ra (ET CO2) c th c gi tr tin lng v cc bnh nhn sng st c ET CO2 cao hn mt cch c ngha thng k so vi nhng ngi t vong. Tuy nhin, theo di CO2 trong kh th ra c th gp nhiu vn : N b nh hng bi bicacbonate tim tnh mch v bi nhng thay i ca thng kh nhn to. Ngoi ra, ngi ta cng nhn thy khi dng adrenaline liu cao th ET CO2 gim xung.

3.5. Khi no ngng hi sc tim - phi:

Khng c quy nh chnh xc no v vic ngng cp cu ngng tim - phi, tuy nhin cn da vo cc yu t sau:

3.5.1. Thi gian ngng tun hon: Ngi ta chng minh tin lng tu thuc vo phc hi tun hon t pht

nhanh hay chm. Tuy nhin, thi gian ngng tun hon rt kh xc nh nu khng c nhn chng.

3.5.2. Tnh trng thn kinh ca bnh nhn trong qu trnh hi sc:

Khng nn da vo ngng hi sc sm. Gin ng t 2 bn khng nht thit l du hiu ca tn thng no khng hi phc v khng c da vo du hiu ny nn ch hoc ngng cp cu. 3.5.3. Tnh trng sinh l v tin cn ca bnh nhn:

Thng khng r v kh xc nh lc cp cu.

3.5.4. Cc khuyn co hin nay: a s cc khuyn co cho rng ch nn ngng hi sc nu bnh nhn vn v

tm thu d hi sc cp cu trn 30 pht v tt c cc bin php hi sc u c thc hin v thc hin ng. Tuy nhin, iu ny khng p dng cho cc trng hp c yu t bo v no lc ngng tim. l trng hp h thn nhit hoc ng c thuc ng bacbituric; khi phi tip tc ko di cc n lc hi sc v vn c th thnh cng. Quyt nh ngng hi sc l 1 hnh vi y khoa do bc s trc tip cp cu bnh nhn chu trch nhim.

4. T chc v c im ca cp cu ngng tim-phi tu theo ni xy ra.

4.1. Ngoi bnh vin:

Tin lng ca ngng tim ngoi bnh vin tu thuc ch yu vo thi gian t lc ngng tim n lc phc hi tun hon t nhin. V vy cp cu cng sm th tin lng cng tt.

4.1.1. Cc mt xch ca vic cu sng bnh nhn hay dy truyn cp cu:

Gn y nhiu nghin cu cho thy c nhng iu kin nu c thc hin sm s ci thin c tin lng. Cc iu kin ny to nn 4 mt xch ca 1 ''dy truyn cp cu". Nu " dy truyn cp cu " din tin hon ton ng th c th cu sng c trn 30% cc trng hp rung tht xy ra ngoi bnh vin.

+ Mt xch u tin l bo ng sm: bo ng nhanh nht cho cc i cp cu. Bo ng nhanh v chnh xc l mt yu t c bn ginh thng li v thi gian. Bo ng sm khng nhng cho php cc i cp cu ti nhanh m cn mang n cc phng tin cp cu ban u ngay lp tc ph hp vi tnh hnh.

+ Mt xch th hai l nh nhng ngi c mt ti ch tin hnh cp cu. Nhiu cng trnh cho thy tin lng ngng tim - phi s tt hn nu hi sc c bn c tin hnh sm trc khi i cp cu ti. Tuy nhin iu ny i hi phi c cng tc o to rng ri trong qun chng nhn dn nh thc hin mt vi ni trn th gii. Cht lng ca vic o to ny thng l hn ch, nht l vi kiu o to t xa. ci thin tnh hnh c hai gii php c ngh mi y:

- o to cho chnh nhng ngi c nguy c v gia nh h: V d nh o to cho cc gia nh bnh nhn b bnh mch vnh, c bit l i vi cc bnh nhn c tin s rung tht v thm ch dy cho h bit cch ph rung vi my t ng.

- Hng dn k thut hi sinh tim - phi c bn qua in thoi: Seattle v Culey Eisenderg chun b sn cc ng in thoi ring, n cho php ngi trc in thoi ca trung tm cp cu hng dn cho ngi gi n thc hnh ng tc cp cu.

+ Mt xch th 3 l ph rung sm. Tin lng ca rung tht trc ht gn lin vi s ph rung nhanh chng. T nhiu nghin cu thc nghim v lm sng vo gia nhng nm 80 chng minh r iu ny. V vy cc nc Anh - M ngi ta trang b cc my ph rung cho cc nhn vin cp cu c th can thip ngay ti ch. Nh cng ngh pht trin, ngy nay c cc my ph rung c kh nng t nhn bit rung tht: cc nhn vin cp cu s gn cc in cc trung gian vo bnh nhn, my s t phn tch nhp tim v ph rung khi pht hin c rung tht (my t ng hon ton), hoc ph rung do nhn vin cp cu trc tip s dng (my bn t ng).

T , k thut ny c a vo p dng nhiu nc v em li thnh cng ng k. Php vic p dng thng bo in tim qua in thoi cho bc s v tin hnh ch o t xa k thut ph rung ang c xem xt v trong tng lai cc my ph rung t ng c th s c trang b cho cc i cp cu.

+ Mt xch th 4, mt xch cui cng l hi sc chuyn su. Khng nn nh gi qu cao mt xch ny bi v nu khng c mt kt qu hi sc hon ho trc th khi bnh nhn n c vi k thut hi sc chuyn khoa qu mun. Nhng cng khng nh gi thp n bi v trong trng hp rung tht c ph rung thnh cng, s ti rung tht sm l rt thng gp, hn na tnh trng tim mch c n nh sm s lun lun l iu cn thit cho mt tin lng kh quan v bn vng. 4.1.2. Ngng tim - phi cc bnh nhn trong bnh vin:

Khi ngng tim phi xy ra t ngt mt khoa trong bnh vin khng c theo di t trc th vic cp cu cng tng t nh ngoi bnh vin. Do vy bnh vin cn t chc 1i cp cu c ng trang b my ph rung cng nh l cc dng c khc cn thit cho hi sc chuyn khoa. Cc i ny s nhanh chng n cp cu cc khoa ngay khi xy ra ngng tim - phi.

Vic cp cu ngng tim - phi trn mt bnh nhn ang c theo di v thng kh nhn to s c nhng c im ring, trong trng hp ny, ngng tim phi c th xy ra ngay khi t ni kh qun do phn x dy X, ri lon nhp tht, t ng sai v tr. Ngng tim c th xy ra t ngt sau 1 bin chng huyt ng i km tnh trng gim khi lng mu lu hnh hoc gin mch cp, tc dng bt li ca cc loi thuc gy m, phm sai lm trong khi s dng cc kh gy m bay hi, trn kh mng phi ln bnh nhn th my, nhng trc trc ca my th, tc ng NKQ sau nhiu gi thng kh... Hi sc ngng tim phi bnh nhn ang c thng kh cn thay i ngay tnh hiu qu ca thng kh. Nu lng ngc khng phng ln, phi ngh ti mt trc trc hoc mt in my th v phi thng kh ngay bng bp bng vi oxy nguyn cht. Nu my th m bo hon ton tt cn ngh n tc ng ni kh qun hoc tt ng, trong trng hp ny phi rt ng ngay lp tc v thng kh cho bnh nhn bng masque vi xy v t li ng NKQ. Trng hp ng nm ng v lu thng tt phi ngh ti trn kh mng phi, nht l khi bnh nhn ang th my c PEEP hoc vi p lc cao. Trong trng hp ny cn phi chc ht kh mng phi bng bm tim trc khi dn lu. Nu cc chn on trn u b loi tr th nn ngh n mt co tht ph qun nghim trng.

5. cp cu mt s tnh hung ngng tim - phi c bit. 5.1. T chc cp cu ngng tim - phi:

Vi mc tiu chn on nhanh, p dng ngay v ng cc ng tc c bn ca hi sc, nhanh chng a nn nhn n cc c s chuyn khoa hoc gi in,

i cp cu c trang b ti cp cu ti ch nn cc nc pht trin ngi ta tin hnh cc phng php sau y:

- Gio dc cho ton th nhn dn qua cc lp o to ngn hn cc c quan, trng hc, cc t chc x hi ... v cc kin thc chn on nhanh v ngng tim - phi v cc ng tc cn thit phi lm khi gp nn nhn ngng tim - phi.

- T chc cc nhm cp cu lu ng kiu nh SAMU ca Php. Hoc cp cu 05 H Ni, thnh ph H Ch Minh.

- T chc h thng bo ng cp cu nhanh v c hiu qu thng xuyn qua in thoi.

- Cc bnh vin phi lun c mt nhm thng trc l cc bc s, y t hi sc c trang b c th ngay lp tc ng cu hoc tip nhn cc bnh nhn b ngng tim - phi cc khoa phng khc hoc t ngoi vo.

5.2. Ngng tim - phi trong chn thng:

Ngng tim - phi trong a chn thng thng kh hi sc v cn ch n mt s im c bit sau y:

- B khi lng tun hon cng nhanh cng tt bng HTM 9%o, ringerlactat, dch keo, mu, hai chn cao hoc mc qun chng sc.

- Nu c chn p trong lng ngc (trn kh, mu mng tim, mng phi) cn phi c chc ht v dn lu ngay.

- Nu tn thng ty sng cao gy cng ph giao cm cn iu tr bng atropin liu cao.

- Nu ngng tim - phi do tng kali cao t ngt vi toan chuyn ho do b gip nt cc chi th hoc hi chng vi lp cn cho bicarbonat sm, v cho canxichlorua.

5.3. Ngng tim - phi do ng c:

Nu ngng tim - phi c lin quan vi c ch h hp do dng cc thuc ng bacbiturate, benzodiazepine hay cc thuc h morphine th ch cn hi sc chuyn khoa theo kinh in l . Nhng nu c nhim c tim mch th cn c iu tr c hiu hn. Tuy nhin trong mi trng hp h hp vi oxy 100% cng hn ch c c tnh ca nhiu loi thuc.

5.3.1. Nhng im c bit ca ngng tim - phi do ng c: * Ngng tim: - Tim atropine liu cao nu ng c photpho hu c. - Tim thuc i khng nu ng c cyanuare (bng hydroxocobalamin)

hoc nu ng c bi cht c ch canxi hoc cc cht gn canxi (bng truyn mui canxi).

* Nu c rung tht hoc nhp nhanh tht c tun hon khng hiu qu: iu tr bng sc in, tim lidocaine hoc diphenyl hydantoine (ng c digitalis) nhng cn cnh gic khng c nhm: rung tht vi xon nh; nhp nhanh tht vi nhp nhanh trn tht c QRS gin rng.

* Nu c xon nh: iu tr yu t gy xon nh (h canxi mu, h kali mu); tim magi; lm tng nhp tim bng my to nhp tim hn l bng isoprenaline.

5.3.2. iu tr tip sau: * Nu vn cn cc ri lon dn truyn: - Nhp chm tim: tim atropin. - Nghn nh - tht (bloc A-V): my to nhp tim hoc dng isoprenaline. - Ri lon dn truyn trong tht vi QRS gin rng > 0,12 giy: tim mui

natri u trng (lactate hoc bicarbonate). - Khong QT ko di l tin triu ca cn xon nh: iu tr h canxi mu

hoc h kali mu. * Nu ri lon tnh kch thch ca c tim: - Lidocaine trong trng hp ngoi tm thu tht a dng a hoc cn nhp

nhanh tht. - Dng betabloquants (thuc c ch beta adrenergic) phng ti pht ca

nhp nhanh tht c lin quan vi hi chng tng adrenergic. * iu tr suy tim: bng cch cho truyn thuc tng sc co bp c tim:

adrenaline, dopamine, dobutamine bng bm tim in. 5.4. Ngng tim ph n c thai:

Nhng ng tc c bn ca hi sc vn gi nguyn nh vi bnh nhn khc. c bit vic dng adrenaline vn c ch nh nh bnh thng mc d c nguy c lm co mch mu ca t cung-rau. Cn ch mt s im sau:

* Khi tin hnh p tim ngoi lng ngc phi k cao vng mng sn hoc mng bn phi ca nn nhn y t cung sang pha bn tri v lm tng mu tnh mch tr v.

* Nu nh thai c nhiu kh nng sng st phi chun b tin hnh m ly thai cp cu trong khi vic hi sc tim - phi cn cha c hiu qu. Vic m ly thai, nhanh trong vng 4-5 pht sau khi ngng tim s ci thin c hi sng st ca c m v thai nhi. Nu cp cu tt sau khi m ngng tim ti 20 pht th thai nhi vn c th sng st khng c di chng.

5.5. Ngng tim - phi do in git:

5.5.1. Nguyn nhn gy ngng tim: * Ch yu l do rung tht nhng i khi ngng tim ngay (v tm thu). * Thiu oxy ch yu do co cng cc c h hp.

5.5.2. Cc im c bit khi cp cu: * Ngi cp cu trnh khng b cng ko vo tai nn in, phi trnh tip

xc vi ngun in, ct in, gi ngi chuyn mn v in nu l in cao th. Tm mi cch a nn nhn ta khi ngun in cng nhanh cng tt.

* u tin ph rung tim mt cch h thng ngay lp tc. * C nh ct sng phi c lm mt cch h thng v n c th gy v ng

cao hoc do co c qu mnh. * m bo b dch ng tnh mch v cho bicarbonat nu chy bng do in

vo su ( ging hi chng vi lp hoc dp nt t chc ln). 5.6. Ngng tim - phi do cht ui:

* Ngi cp cu khng nn mo him khi c cu nn nhn di nc, cn c phao hoc thuyn cu tr. Phi tin hnh cc ng tc s cu c bn d cho bnh nhn b chm xung nc lu v thng c h nhit

* Cn c nh ct sng nu nghi c tn thng tu c do ng trc khi cht ui. * Lng nc nm trong ng th thng t v nhanh chng b hp thu vo

h tun hon, do vy khng nn dc ngc nn nhn hoc ht ph qun lu i khi gy nguy him, tuy nhin cn ht nc trong d dy, trnh gy cn tr hot ng ca c honh.

* Sau khi hi phc c hot ng t ng ca tim c hiu qu, cho th my vi p lc dng cui th th ra (PEEP) chng ph phi do tn thng.

* Cn phn bit cht ui nc ngt vi cht ui nc mn: + Trong cht ui nc ngt thng gy tha khi lng tun hon, tn

thng lp surfactant ca phi v cc ph nang c th xp gy tng hiu ng shunt trong phi.

+ Cht ui nc mn thng thiu khi lng tun hon nhng cc ph nang b lp y nc v xp phi gy tng hiu ng shunt trong phi.

Nhng hu qu chung vn l ph phi v thiu oxy do tn thng ph nang.

5.7. Ngng tim - phi nhit thp:

- Trc tin cn phi bit chn on ngng tim - phi trong iu kin tt nhit nghim trng v bt u hi sc ngay khi nghi ng v hot ng ca tim kh nhn bit do co mch.

- Ngng tim - phi nhit thp c c im: tt nhit lm tng kh nng chu ng ca no vi thiu oxy (15 pht 25oC, 30 pht 20oC, 60 pht 15oC ).

- Tn s p tim ngoi lng ngc v thng kh nhn to phi gim i mt phn t trong trng hp nhit tt < 28oC.

- Nu c rung tht th cn lm sc in. Tuy nhin rung tht th tr vi sc in ngoi nu thn nhit di 30oC. Khi mt s tc gi cho rng c th dng bretylium cho kt qu tt.

- Trc mt trng hp ngng tim - phi c tt nhit nghim trng cn si m t trong (th kh m, ra mng phi hoc mng bng bng nc m 40-42oC), c th m lng ngc bp tim trc tip v lm m tim trc tip. Vic p dng tun hon ngoi c th cho php nng ti a 10-15oC/gi v n cn c ch trnh phi p tim ko di, ngoi ra cn h tr c tun hon cho c th.

Bng 1 : cp cu ngng tim phi

(Theo cc khuyn co ca Hi Hi sc Chu u- European ResuscitationCouncil).

C phn ng? Bng li v/hoc

vn ng.

C

Bo v, theo di v nh gi li

1 cch nh k.

Ku gi gip nu cn.

Khng

Th c hiu qu:

H hon gi ngi

gip .

+ Hnh ng A:

- Cho nm nghing t th an ton.

Gi (hoc nh gi) ngi gip.

Khng thy th c hiu qu, Bt c mch: Gii phng ng th. + Hnh ng B. nh gi h hp. - Thi h hp nhn to 10 ci/pht,Kim tra mch. (ming - ming).

- Gi (hoc nh gi) ngi gip.

- Tip tc h hp nhn to

ming - ming.

Khng bt c mch:

+ Hnh ng C:

- Gi (hoc nh gi) ngi gip.

- Bt u p tim ngoi lng ngc

(ETNLN).

Bng 2: Quy trnh iu tr rung tht v nhp nhanh tht

ng tc cp cu c bn:

ETNLN + h hp nhn to (1)

(1) Ch tm ngng cc ng tc cp cu c bn trong thi gian tht ngn kim tra mch, sc in hoc thc hin cc k thut hi sc khc

Sc in cho n 3 ci: 200J (2 ln) 300J, 360J

(2) Mch? Nhp? Nu rung tht c thay th bng phn ly in c hoc v tm thu th chuyn sang quy trnh tng ng.

Mch? Nhp ? (2) Tip tc cc ng tc cp cu c bn

(3) Nu tht bi c th tng liu adrenaline ln 3 - 5 mg tnh mch/3 pht 1 ln

(4) C th lp li lidocaine mi 5 pht

t ni kh qun- t ng truyn tnh mch

n tng liu 3 mg/kg. Nu tht bi c th dng cc thuc chng lon nhp khc

(5) Bicarbonate c ch nh tuyt i trong trng hp c tng kali mu hoc toan

Adrenaline tnh mch 1mg/3pht (3) huyt c t trc, bicarbonate c th c li khi ngng tim ko di > 15 pht.

Mch? Nhp ? (2)

Tip tc cc ng tc cp cu c bn

Sc in 360J n 3 ln nu cn

Mch? Nhp ? (2) Tip tc cc ng tc cp cu c bn

Lidocaine tnh mch 1,5 mg/kg (4)

Sau liu u 1mmol/kg tim lp li 0,5 mmol/kg mi 10 pht

Sc in 360J n 3 ln nu cn

Mch? Nhp ? (2) Tip tc cc ng tc cp cu c bn

Bicacbonate tnh mch 1 mmol/kg (5)

Bng 3: Quy trnh cp cu v tm thu.

Cc ng tc cp cu c bn:

ETNLN+ h hp nhn to (1)

(!) Ch ngng cc ng tc cp cu c bn trong thi gian tht ngn kim tra mch, sc in hoc thc hin cc th thut hi sc khc.

Loi tr rung tht: kim tra li

in cc, dy cp... (2)

(2) Nu nghi ng th sc in.

(3) Nu tht bi c th tng liu adrenaline ng tnh mch 5mg /3 pht.

t ni kh qun, t ng

truyn tnh mch

(4) Nu v tm thu c thay th bi 1 bnh cnh khc chuyn sang quy trnh tng ng.

Adrenaline ng tnh mch

3mg /3 pht (3)

(5) C ch nh tuyt i trong trng hp c tng kali huyt hoc toan huyt c t trc. Bicarbonate c th c li khi ngng tim ko di (>15 pht). Sau liu u 1 mmol/kg tim lp li 0,5 mmol/kg mi 10 pht.

Mch? Nhp ? (4)

Tip tc cc ng tc cp cu c bn

Bicarbonate 1mmol/kg tnh mch (5)

Mch? Nhp ? (4)

Tip tc cc ng tc cp cu c bn

Bng 4: Quy trnh cp cu cc lon nhp khng c mch khc (1)

Cc ng tc cp cu c bn: ETNLN + h hp nhn to (2)

(1)

(2) t ni kh qun - t ng truyn

tnh mch

(3) Xem xt gii quyt ngay nguyn nhn sau: (3) * Gim khi lng tun hon. * Trn kh mng phi c p lc. * Chn p tim. * Ng c thuc c ch co bp c tim. * Tng kali mu, toan huyt. * Tc mch phi, nhi mu c tim rng. * H thn nhit

(4) (5)

(6) Adrenaline 1mg/3 pht tim tnh mch (4)

(7) Mch? Nhp ? (5)

Tip tc cc ng tc cp cu c bn

Atropine nu nhp chm: 1 mg tim tnh mch (6)

Mch? Nhp ?

Tip tc cc ng tc cp cu c bn

Bicarbonate 1 mmol/kg tnh mch

Mch? Nhp ?

Tip tc cc ng tc cp cu c bn

Cc lon nhp khng c mch khc gm: phn ly in c, lon nhp chm, nhp t tht sau sc in ph rung. Cc ng tc cp cu c bn ch c tm ngng trong thi gian tht ngn kim tra mch, sc in hoc thc hin cc th thut hi sc khc. Gim khi lng tun hon: b dch, trn kh mng phi c p lc: chc ht ph mc gim p; ng c thuc c ch co bp c tim; iu tr sc tim, tng kali mu, toan huyt: bicarbonate; tc mch phi, nhi mu c tim: nong mch vnh, thuc tiu si huyt, chng h thn nhit. Nu tht bi tng liu adrenaline ln 3 - 5 mg 1 ln / mi 3 pht. Nu xut hin v tm thu hoc rung tht th chuyn sang quy trnh tng ng

Thuc vn mch v cng tim dng trong hi sc cp cu

Trn Duy Anh

1. Cc th th adrenergic ca h thng tim mch. Cc thuc tim mch s iu chnh hot ng ca tim, mch, kh ph qun v

trng lc c trn ca ng tiu ho thng qua cc h th cm adrenergic. C 3 nhm th cm th h adrenergic.

+ - adrenergic (1 v 2). + - adrenergic (1 v 2). + dopaminenergic. Cc cathecholamine c nhng i lc kt gn khc nhau vi cc th cm th h

adrenergic.

Bng 1:

Cc amine giao cm

Liu tim tnh mch thng

thng

Hiu qu trn h th cm adrenergic

Nguy c gy lon

nhp

Epinephrine (adrenalin)

0,5 - 1mg

1 - 200g/pht +

+ + + +

+ + + + + + + + +

Norepinephrine

(levophed)

2 - 80g/pht + + + + + + +

Dopamine (intropin)

1 - 2g/kg/pht 2 - 10g/kg/pht 10 - 30g/kg/pht

+ + +

+ + +

+ (*) + + + +

+ + +

+ + +

Dobutamine (dobutrex)

2 - 30g/kg/pht + + + + + +

Isoproterenol

(isuprel)

2 - 10g/pht 0 + + + + + +

Marinone (inocar)

2 - 15g/kg/pht 0 0 (**) + +

(*) Tng dng mu thn.

(**) phosphodiesterase inhibitor-cht c ch men phosphodiesteraza. Cc th cm th 1 c vng sau xinp ca tim, cc nron thn kinh v cc

c trn mch mu. Kch thch cc receptor 1 mch mu s dn ti co mch. Cc th cm 1 c tim lm tng va sc co bp c tim v chm nhp tim. Hiu lc tc dng ca cc thuc nhm adrenergic trn 1 - receptor theo th t tng dn: phenylephrine, norepinephrine v epinephrine.

Cc receptor trn xinp 2 iu chnh trng lc mch mu cc mch mu ln v to thnh mt c ch iu chnh i khng vi tc dng ca cc 1 - receptor. Khi nhng 2 - receptor b kch thch n s hn ch tch ly norepinephrine. h thng thn kinh trung ng, s kch thch cc 2 - receptor s c ch cung phn x vn mch dn ti gin mch ngoi vi. Cc receptor 2 sau xinp cng c th gy co cc tiu ng mch v tnh mch.

Kch thch cc 1 - receptor lm tng nhp tim v tng sc co bp c tim. Kch thch 2 - receptor s lm gin mch, gin c trn ph qun, niu qun v ng tiu ho. 2 -receptor cng hot ho chuyn ho m, phn hu glycogen v a ion kali vo trong t bo gy gim kali mu. Hiu qu ny c th ng vai tr quan trng trong iu tr lon nhp tim khi c thiu mu c tim v c th gii thch cho hiu qu u vit ca nhm c ch d phng cc bin chng cp v th pht sau nhi mu c tim. Kch thch cc th cm th 2 - adrenergic dn n gim renin-mt cht b c ch bi liu cao cc thuc c ch . ng mch vnh c c 2 loi th cm th v - adrenergic.

Dopamine liu thp s kch thch h th cm dopaminergic gy ra gin mch mu thn v mc treo rut, nhng trng lc ca tnh mch li tng ln nh kch thch h - adrenergic. nng cao hn, nhng tc dng u th trn - adrenergic ca dopamine s gy co cc mch mu thn v mc treo rut.

Nhng nghin cu sinh ho t bo cho thy l cc th cm th - adrenergic chim u th nhng ng mch vnh c kch thc ln bao ngoi tim, cn nhng th cm th - adrenergic chim u th nhng ng mch vnh nh. Kch thch cc -receptor (v d bng cc tc nhn ging nh norepinephrine hoc dopamin hoc do kch thch h thn kinh giao cm) s gy ra co tht mch vnh. Co tht mch vnh thng thng b khng ch ngay bi cc yu t chuyn ho ti ch nh adenosin-mt cht c sinh ra trong qu trnh hot ng ca tim. nhng bnh nhn c cc bnh mch vnh, s co tht ng mch vnh do mt tc nhn kch thch no c th b tng ln v thng xut hin nhng p ng tri ngc do tn thng ni mc. V vy cc cathecholamine c hot tnh ging - adrenergic cn c s dng mt cch thn trng nhng bnh nhn c nhng bnh l thiu mu c tim cp. Nhng th cm th 2 sau xinp c th gi v tr trung gian c bit quan trng i vi co tht mch vnh. Cc thuc nhm chn dng Ca++ lm gim s co mch qua trung gian th th 2, iu ny gii thch cho tc dng chng co tht mch vnh ca chng. Kch thch cc th th -adrenergic thng gy gin mch vnh.

Trng lc ca h adrenergic (giao cm) l cn bng vi h ph giao cm v c iu chnh bi h thn kinh ny. H thn kinh giao cm v ph giao cm c nh hng trc tip ti chc nng in sinh l v co bp ca mch vnh. Ngoi ra cn mt s c ch khc gy co gin bt thng ca mch vnh:

+. S mt cn bng gia nhng sn phm trung gian hot ho ca tiu cu nh thromboxane A2 v prostacyclin.

+. Ri lon chc nng ca t bo ni mc dn ti p ng nghch thng vi kch thch gin mch bnh thng.

+. Mt nhng cht gin mch nh yu t gii phng t t bo ni mc.

2. Nhng thuc lm tng sc co bp c tim v tr-ng lc mch mu. 2.1. Norepinephrine:

*C ch tc dng: Norepinephrine l 1 cathecholamin c chit xut t t nhin, n ch khc

vi epinephrine bi khng c nhm methyl amine cui cng. Epinephrine v norepinephrine gn ging nhau v kh nng kch thch cc th th 1 - adrenergic (trn tim), nhng hiu qu kch thch trn th th 1 v 2 - adrenergic l rt khc nhau. Norepinephrine l cht ch vn ca th cm th m rt t nh hng trn th th 2. Norepinephrine lm tng tnh co bp c tim do tc dng trn th cm th 1 - adrenergic. Tc dng ca n trn th th dn ti co ng mch v tnh mch. Tc dng tng sc co bp c tim (inotrope (+)) ca norepinephrine c ng dng trong iu tr cc trng hp shock nng. Cn lu tc dng gy tng sc cn mch mu ca norepinephrine c th s lm mt tc dng inotrope (+) ca n. Norepinephrine lm tng huyt p do tng sc cn mch mu h thng nhng c th khng ci thin hoc thm ch lm gim cung lng tim. V norepinephrine lm tng nhu cu O2 c tim cho nn c th lm tng thiu mu c tim, c bit do kch thch cc th cm th mch vnh nn c th gy ra co tht mch vnh nhng bnh nhn c bnh thiu mu c tim. Norepinephrine c s dng nh 1 bin php cui cng trong cp cu ni khoa.

* Ch nh: Thuc c dng trong iu tr tt huyt p nng m cc amin giao cm khc

khng cn hiu lc. norepinephrine c tc dng tt hn nhng trng hp c sc cn ngoi vi thp. Tt huyt p v sc cn ngoi bin thp him gp trong nhi mu c tim cp (NMCTC) nhng li thng gp trong shock nhim trng v shock c c ch thn kinh. Vic s dng norepinephrine cn c xem nh 1 bin php tm thi. Bi v kt qa iu tr ph thuc khng ch n thun l nng c huyt p m cn i hi phi iu chnh cc bt thng khc km theo trong trng thi shock.

* Liu lng:

Norepinephrine bitartrate USP c ng trong nhng ng 4ml; mi ml cha 1mg norepinephrine nguyn cht v 2mg norepinephrine bitartrate. Cn trn n vi 250ml dung dch dextrose 5% hoc mui ng trng c c m 16g/ml. Phi truyn norepinephrine qua 1 catheter tnh mch trung tm gim ti a nguy c truyn ra ngoi tnh mch (xem phn ch ). Liu truyn ban u thng dng l 0,5 - 1g/pht. Sau chnh tc truyn t c tc dng mong mun l duy tr huyt p va (tiu chun hp l l huyt p tm thu t nht 90mmHg) vi liu nh nht c th c. Liu trung bnh ngi ln l 2-12g/pht. Nhng bnh nhn shock nng c th cn liu ln ti 30g/pht. Norepinephrine phi c truyn qua bm tim in m bo tc dng chnh xc. Vic s dng thuc ny phi c xem nh mt bin php tm thi, cn gim liu hoc ngng truyn cng sm cng tt v chuyn sang dng mt loi amin giao cm khc, cn gim liu norepinephrine t t trnh tt huyt p t ngt, nng.

* Ch : Cc bin php o huyt p ngoi bin trong shock thng l khng chnh xc

do hin tng co cc mch mu ngoi vi, cho nn theo di lin tc huyt p ng mch trc tip l cn thit xc nh chnh xc mc huyt p ng mch ca bnh nhn. Nu huyt p o trc tip v huyt p o gin tip bng ti hi l nh nhau th ngng theo di huyt p o trc tip.

Khi khng dng phng php theo di huyt p ng mch trc tip na th cn theo di huyt p c 5 pht 1 ln bng ti hi hoc bng doppler trong sut qu trnh iu chnh liu thuc. bnh nhn c iu tr bng thuc vn mch norepinephrine cn c theo di cc ch s huyt ng nh gi nhng thay i ca cung lng tim, p lc ng mch phi bt v sc cn ng mch ngoi bin.

Norepinephrine lm tng nhu cu O2 c tim m khng km theo tng b tr lu lng mu vnh. N c th c hi bnh nhn thiu mu c tim hay l nhi mu. norepinephrine c th gy kch thch gy lon nhp c bit nhng bnh nhn c gim th tch mu lu hnh v nhng bnh nhn c vng c tim lnh cn t. Tt huyt p do gim th tch mu l chng ch nh dng norepinephrine, tr khi n l mt phng php tm thi duy tr ti mu vnh v no cho ti khi vic b dch c thc hin. Hin tng thot mch ca norepinephrine c th s gy ra hoi t t chc (do thiu mu cc b) v hin tng ni da g. Nu s thot mch xut hin, tim phentolamin (5 - 10mg ho vi 10 - 15ml dung dch mui ng trng) vo vng chng li tc dng co mch ca norepinephrine v gim ti a hin tng hoi t.

2.2. Dopamin:

* C ch tc dng:

Dopamin hydrochloride l cht ho hc tin thn ca norepinephrine kch thch h dopaminergic, cc th cm th 1 hay adrnergic tu thuc vo liu lng khc nhau ca thuc. Dopamin cng kch thch vic gii phng norepinephrine. Dopamin liu thp (1-2 g/kg/pht) kch thch cc th th dopaminegic gy gin mch mc treo, thn, no, nhng lm tng trng lc tnh mch do kch thch th th - adrenegic ca tnh mch. S lng nc tiu c th tng nhng tn s tim, huyt p thng l khng i. Vi liu 2-10g/kg/pht dopamin kch thch th cm th 1 v - adrenergic. Kch thch th th 1 - adrenergic lm tng cung lng tim v i khng 1 phn vi th th - adrenergic gy co mch. N rt c tc dng trong tng cung lng tim v km tng rt t sc cn ngoi bin.

liu trn 2,5/kg/pht dopamin lm tng trng lc tnh mch v p lc tnh mch trung tm. Liu trn 10g/kg/pht tc dng trn th th - adrenergic ca dopamin chim u th, n gy ra co ng mch thn, mc treo, ng mch ngoi bin, sc cn ng mch phi v xa hn na l tng tin gnh. Liu trn 20g/kg/pht gy ra hiu qu huyt ng tng t nh ca norepinephrine. p ng ca c th vi dopamin so vi cc thuc vn mch khc l rt khc bit, do phi chnh liu thuc da vo hiu qu huyt ng. Dopamin lm tng cng c tim khng km tng lu lng ti mu vnh b tr, s mt cn bng gia cung v cu O2 ny c th gy ra thiu mu c tim cp.

* Ch nh: Ch nh dng dopamin l tt huyt p nng khng km gim th tch mu

lu hnh (tt huyt p nng l huyt p ng mch tm thu di 90mmHg km theo cc triu chng gim ti mu m: thiu niu, hay nhng thay i thc). Dopamin nn s dng vi liu thp nht c th duy tr mt mc ti mu cho cc c quan sng quan trng (no, tim, gan, thn...). Tng sc cn mch mu, huyt phi hay tng tin ti l nhng chng ch nh ca dng dopamin. Trong nhng trng hp ny dopamin cn dng liu thp (1-2g/kg/pht) lm tng ti mu thn. Vic iu tr bng dopamin thng dnh cho nhng bnh nhn c tt huyt p xut hin cng vi nhp chm hay sau khi ti lp tun hon t pht cc trng hp ngng tim - phi. C th phi hp norepinephrine vi dopamin nu liu dopamin vt 20 g/kg/pht. Theo Gonzalez vic kt hp dopamin v epinephrin khng sinh ra mt tc dng vn mch hip ng no cc bnh nhn ngng tim - phi. Mt nghin cu mi y s dng m hnh trn bnh nhn ngng tim - phi chng t rng dopamin t hiu qu hn epinephrin trong tc dng ci thin huyt ng ca qu trnh hi sc. iu quan trng cn nh rng nhng tc dng trn th th - adrenergic ca dopamin d liu thp cng lm tng p lc ng mch phi bt v c th gy ra hay lm nng ln tnh trng huyt phi mc d n c lm tng cung lng tim. Cc thuc gin mch (nh nitroglycerin, nitroprusside) c th c dng phi hp lm gim tin gnh, tng cung lng tim bng cch i khng vi tc dng tng sc cn ng mch v tnh mch ca dopamin. S kt hp dopamin v nitroprusside cho ta hiu qu huyt ng tng t nh dobutamin.

* Liu lng:

Dopamin ch c dng bng ng tnh mch. Trn 1 hoc 2 ng (200mg/ng) dopamin trong 250ml dextrose5%. Thu c dung dch c nng 800 hoc 1600g/ml. Tc truyn ban u l 1-5g/kg/pht. C th tng tc truyn cho ti khi ci thin c huyt p, lng nc tiu v cc du hiu ca tng ti mu cc c quan. Liu thng dng l 5-20g/kg/pht. gim ti thiu cc tc dng ph, cn dng dopamin liu thp nht c th cho php m vn t c s ci thin huyt ng. Phi dng dopamin qua bm tim in m bo chnh xc liu lng thuc. nhng bnh nhn c bnh thiu mu c tim hay suy tim huyt, vic theo di huyt ng l quan trng s dng dopamin chnh xc. Theo di huyt ng phi c thit lp trc hay cng sm cng tt sau khi bt u iu tr bng dopamin. Khi cn gim liu dopamin phi gim t t trnh tt huyt p t ngt.

* Ch : Dopamin s lm tng tn s tim v c th gy ra hay lm nng thm nhng

lon nhp trn tht. Ngoi ra d liu thp nh hng gy co ng mch v tnh mch ca dopamin c th lm nng ln tnh trng huyt phi v thay i cung lng tim. i khi nhng nh hng ny c th buc phi gim liu hoc ngng truyn. Mc d c nhng ci thin v huyt ng. Nhng do tng nhu cu 02 c tim v tng to cc sn phm lactat ca c tim, cho nn cn lu l cung lng mu vnh tng b tr khng vi vic tng cng ca tim khi p ng vi liu cao dopamin. S mt cn bng gia cung v cu ny gy ra hoc lm nng thm tnh trng thiu mu c tim.

Bun nn, nn l nhng tc dng ph thng gp ca dopamin, dopamin c th gy ra hoi t da, ni da g khi truyn n vo tnh mch ngoi vi. Khc ph tc dng ph ny ca dopamin cng lm ging nh vi norepinephrine.

Dopamin khng c cho vo cc dch truyn cha natricacbonat hoc cc dch truyn mang tnh cht kim v n b lm bt hot pH kim. Tuy nhin phn ng ny din ra chm dopamin v cc dch kim khc (aminophylin, phenytain, natribicacbonat...) c th truyn trong mt thi gian ngn qua cng mt catheter tnh mch.

2.3. Dobutamin:

* C ch tc dng: Dobutamin l mt amin giao cm tng hp, n c tc dng tng sc co bp c

tim bng cch kch thch cc th th 1 v 1 - adrenergic trn c tim. Dobutamin c kch thch cc th th 1 - adrenergic ngoi bin nhng do n b i khng bi tc dng kch thch th th 2 - adrenergic mnh hn, dn ti p ng gin mch nh. Dobutamin lm tng cung lng tim v gim sc khng mch mu ngoi bin. liu thng thng (2 - 20g/kg/pht) dobutamin t c xu hng gy nhp nhanh hn dopamin hoc isoproterenol. D sao i na liu cao hn dobutamin vn gy ra p ng nhp nhanh. Dobutamin lm tng ti mu thn v mc treo

nh lm tng cung lng tim. N khng th gy ra gin trc tip mch thn v mc treo qua cc th th dopaminenergic. D sao tc dng tng lng nc tiu v ti mu thn l nh nhau gia dopamin v dobutamin. Tng ti mu thn th pht sau tng cung lng tim l mt du hiu rt quan trng nh gi chc nng thn. Hiu qu huyt ng ca dobutamin tng ng vi vic dng phi hp dopamin vi mt thuc gin mch nh nitroprusside. Dobutamin lm tng cung lng tim, gim p lc ng mch phi bt v sc cn ngoi bin .

Nhng u im ca dobutamin v huyt ng v tc dng gii phng norepinephrine ni sinh s dn ti gim ti thiu nhu cu O2 c tim v to ra mt cn bng c li gia cung v cu v O2 ca c tim so vi norepinephrine v dopamin. Tc dng inotrope(+) cng khng c ci thin do tng ti mu vnh. V nhng l do trn dobutamin khng lm tng kch thc nhi mu hoc khng gy lon nhp tim. Tn s tim c th gim khi huyt ng ci thin. nh gi p ng lm sng vi dobutamin cn theo di huyt ng trung ng trc tip. Ngi ta dng kt hp hai thuc dopamin v dobutamin vi nhau liu trung bnh (7,5g/kg/pht) duy tr huyt p ng mch v hn ch tc dng gy tng p lc ng mch phi bt v tnh trng huyt phi ca dopamin n c. S kt hp dopamin v dobutamin trong iu tr s ci thin ng k huyt ng nhng n khng lm thay i t l sng st bnh nhn shock tim.

* Ch nh: - Dobutamin rt hu ch trong iu tr cc trng hp huyt phi v cung

lng tim thp cng nh l cc bnh nhn c tt huyt p km huyt phi v ri lon chc nng tht tri m khng dng c cc thuc gin mch.

- Dobutamin c chn iu tr suy tim c ri lon huyt ng nng bnh nhn nhi mu c tim cp (NMCTC).

- Dobutamin cng c th c dng ci thin cng tht tri bnh nhn shock nhim trng.

* Liu lng: Dobutamin c th c hiu qu liu thp ( 0,5g/kg/pht) liu thng thng l

2-20g/kg/pht. Dobutamin lm tng tn s tim > 10% so vi ban u, l iu cn trnh bnh nhn c bnh l ng mch vnh. Trn 2 ng (ti 4 ng) dobutamin (250mg/ng) vo 250ml dextrose 5% hoc dung dch mui ng trng. Phi truyn dobutamin qua bm tim in m bo tc dng chnh xc.

* Ch : Dobutamin c th gy ra nhp nhanh, lon nhp v huyt p dao ng. N c

th gy thiu mu c tim nht l khi xut hin tng nhp tim. Cc tc dng ph khc gm: au u, bun nn, run c v h kali mu

2.4. Isoproterenol:

* C ch tc dng:

Isoproterenol hydrochloride l mt amin giao cm tng hp c tc dng chn lc gn hon ton trn th th - adrenergic. Cc c tnh inotrope (+) v iu nhp ca n thng lm tng cung lng tim mc d n lm gim huyt p trung bnh do gin h tnh mch ngoi vi v tng dung tch lng tnh mch. Isoproterenol lm tng ng k nhu cu O2 c tim v c th gy ra hay lm nng thm thiu mu c tim. Cc thuc tng sc co bp c tim mi (dobutamin, amrinone) thay th isoproterenol trn thc t lm sng hin nay.

* Ch nh: Isoproterenol c dng kim sot huyt ng tm thi trong trng hp

c nhp chm nng. Hin nay ch nh chnh l iu tr nhp chm. Tuy nhin trong cc trng hp c nhp tim chm lc u nn s dng atropin, to nhp, dopamin v epinephrine trc khi dng isoproterenol (my to nhp in t gp phn kim sot tt hn isoproterenol m khng km theo tng tiu th O2 c tim v nguy c lon nhp nhanh). To nhp tim nn dng thay cho isoproterenol cng sm cng tt sau khi isoproterenol c ch nh nh mt bin php tm thi. Khi s dng isoproterenol vi mc ch h tr nhp c th lm thiu mu c tim v tt huyt p. Trong iu tr ngng tim khng nn dng isoproterenol.

* Liu lng: Liu h tr nhp tim thng nh, khng ln hn 10g/pht l . Liu bt u

l 2g/pht, chnh liu t t cho ti khi tn s tim khong 60 ln/pht l c. Ho 1mg isoproterenol trong 250ml dextrose 5% s c dung dch nng 4g/ml phi truyn n bng mt bm truyn dch m bo tc truyn chnh xc.

* Ch : Do isoproterenol lm tng nhu cu O2 c tim nn trnh dng khi c bnh l

thiu mu c tim. c tnh iu nhp ca n c th gy ra lon nhp nng nh: nhp nhanh tht, rung tht. N c th lm nng ln cc lon nhp nhanh do ng c digital v c th gy h kali mu.

2.5. Amrinone:

* C ch tc dng: Amrinone l thuc tng sc bp c tim tc dng nhanh c th dng ng

tnh mch. Amrinone l mt thuc c ch phosphodiesterase. Hiu qu ca amrinone trn huyt ng tng t nh dobutamin. liu 2 - 15g/kg/pht n lm tng cung lng tim, gim sc cn ngoi bin v tin gnh. Liu cao hn n gy nhp nhanh ging nh dobutamin. amrinone c th lm thiu mu c tim nng thm v cn thn trng khi s dng thuc ny cho cc bnh nhn b bnh thiu mu c tim. Vic theo di lin tc cc ch s huyt ng trung ng l rt cn thit cho vic iu chnh liu chnh xc khi bt u iu tr bng amrinone.

* Ch nh: Cn cn nhc vic s dng amrinone nhng bnh nhn suy tim huyt nng

khng tr vi cc thuc li tiu, gin mch v cc thuc vn mch thng thng.

* Liu lng: Amrinone c thi gian bn hu di (4 - 6gi). C th s dng liu ln bt u

t 0,75mg/kg. Do tc dng gim hu gnh ca amrinone l trc tip t l vi liu v tc truyn nn liu khi u thng khng vt qu 1mg/kg, liu ny c th truyn trong 2 - 5 pht, nhng tt hn l truyn 10 - 15 pht gim ti thiu nguy c tt huyt p bnh nhn c ri lon chc nng tht tri nng v huyt p ang mc gii hn. Tip theo l liu duy tr bt u truyn tc 2 - 5g/kg/pht v chnh liu 10 - 15g/kg/pht theo s p ng ca huyt ng.

Do tm quan trng ca tnh tng k ho hc amrinone lactat khng c ho trc tip vo cc loi dch dextrose trc khi truyn. Nhng vn c th truyn n qua mt catheter tnh mch cng vi dung dch dextrose. truyn tnh mch lin tc, cn phi pha amrinone vo natriclorua 0,45% hoc 0,9% vi nng 1 - 3mg/ml. Nn dng amrinone qua mt bm truyn dch chnh liu chnh xc.

* Ch : + Amrinone c th gy ra hoc lm xu i tnh trng thiu mu c tim. Theo

di lin tc huyt ng trung ng l quan trng v nhng thay i cc ch s huyt ng trung ng c th xut hin khng ng thi vi nhng bin i ca huyt p v tn s tim. gim ti thiu tc dng ph ca amrinone, nn dng liu thp nht c th t c hiu qu mong mun. Amrinone c th gy ra gim tiu cu (khong 2 - 3% trng hp dng thuc) do n lm gim thi gian sng ca tiu cu. Tc dng khng mong mun ny xut hin trong vng 48 - 72 gi sau bt u iu tr. Gim tiu cu thng l him khi i km chy mu v n mt i khi ngng thuc. Mc gim tiu cu ph thuc vo liu thuc. Cc tc dng ph khc gm: ri lon tiu ho, au c, st, ri lon chc nng gan v kch thch tm tht. Trong phn t amrinone c cha metabisulfit nn chng ch nh dng n bnh nhn d ng vi cc bisulfit.

+ Nguyn tc gim liu cc thuc vn mch: Khi gim liu cc thuc vn mch c tc dng inotrope (+) nn gim t t v

c theo di cht ch v nhng thuc ny tc ng ln vic kim sot thn kinh-th dch i vi huyt p v th tch tun hon. ng thi cn phi m bo b sung y lng dch trong lng mch trnh tt huyt p sau khi gim liu.

2.6. Cc glycozit cng tim (digital glycosides):

* C ch tc dng: Digital glycosides c s dng trong nhiu thp k iu tr cc ri lon

tim. Digoxin l mt dng ca digital glycosides hin ang c s dng rng ri trn thc t lm sng.

Digoxin c kh nng lm tng sc co bp c tim v kim sot p ng tht trong rung, cung nh. C ch tc dng tng sc co bp c tim ca digitalis l c ch Na+ - K+ ATPase mng t bo. Tc dng ny lm thay i dng Ca++ v tng nng Ca++ h li ni bo, nh lm tng tnh co bp. Tc dng inotrope

(+) ca digitalis khng ph thuc vo vic gii phng cc cathecholamin v khng b nh hng bi vic chn cc th th adrenergic. Digitalis gy co mch vnh v mch mc treo.

Digitalis c tc dng trc v gin tip trn nt xoang v nt nh - tht. N lm gim bt mt cch trc tip v gin tip (bng cch tng trng lc ph giao cm) dn truyn xung ng qua nt nh - tht nhng lm tng tn s dn truyn trong nh. Liu digitalis ph thuc vo ng dng v mc ch iu tr. Liu cao thng c ch nh kim sot p ng ca tht trong rung nh hn l lm tng tnh co bp.

Ng c digitalis thng gp khi nng ca n trong huyt tng cao, nhng ng c cng c th xut hin ngay c khi nng digitalis huyt thanh thp. Ngc li c th nng thuc trong huyt thanh cao nhng li khng xut hin triu chng ng c bi v c tnh ca n ph thuc vo lng thuc c trong c tim ch khng phi trong tun hon mu.

* Ch nh: Digitalis gip vic kim sot p ng tht trong rung nh hay trong cung nh

v n c th chuyn nhp nhanh kch pht trn tht thnh nhp xoang bnh thng. bnh nhn c ri lon chc nng tht tri n c th chuyn cung tht thnh rung tht. digoxin c th c ch nh trng hp ri lon nhp trn tht nu bnh nhn c huyt ng n nh m khng i hi sc in o nhp cp cu. Tc dng tng sc co bp c tim ca digoxin dng ung khng mnh bng loi tim tnh mch v cng c hn. Digitalis t c vai tr trong iu tr suy tim huyt cp. Cc nghin cu lm sng ch ra rng cc digitalis c hiu qu huyt ng tt trong iu tr suy tim huyt mn tnh.

* Liu lng: Digoxin c th dng bng ng ung hay tnh mch. Dng digoxin tnh

mch c th trnh c cc vn hp th qua d dy, rut v thi gian bt u c tc dng cng nh thi gian t tc dng nh nhanh hn ng ung. Sau dng ng tnh mch tc dng iu nhp v c ch dn truyn ca digoxin xut hin trong vng 5 - 30 pht, t tc dng nh trong vng 1,5 - 3 gi. Tc dng inotrope (+) xut hin sau p ng in sinh l ca n.

Trong cc trng hp khng phi cp cu, vic iu tr c th bt u bng ng ung. Do thi gian bn hu tng i di ca digoxin (36gi) nn dng bt u bng liu 10 - 15g/kg ni chung l mang li hiu qu iu tr vi nguy c ng c ti thiu. Liu duy tr ph thuc chiu cao cn nng ca c th v chc nng thn.

* Ch : Ng c digitalis l mt vn thng gp v nguy him xut hin vi tn

xut thay i t 7-20%. Thc t c th gp bt c loi lon nhp no trong ng c digitalis, thng gp nht l ngoi tm thu nh, tht, ngoi tm thu tht nhp i v nhp nhanh tht. Nhp b ni nhanh dn, nhp b ni nhanh, nhp nh nhanh kch pht vi bloc nh-tht 2/1, bloc nh - tht cao t gp hn nhng li

l c trng cho cc trng hp qu liu digitalis. Nhng biu hin khc ngoi tim ca ng c digitalis gm chn n, bun nn, nn ma, a chy, ri lon th lc, thay i thc (mt mi, bn chn, lon thn). Ng c thng xut hin nhng bnh nhn c h K+, Mg++, Ca++ mu.

Khi nghi ng ng c digitalis, cn ngng thuc v nh lng nng thuc trong huyt thanh, khi nng thuc bnh thng trong mu l loi tr ng c. Nhng bnh nhn c nng digitalis trn 2,5ng/ml c nguy c ng c cao hn. Vic iu chnh K+ mu l quan trng, mc K+ huyt thanh cn tng cho ti khi n v bnh thng. iu chnh K+ mu cn thn trng bnh nhn c bloc v n c th nng ln do truyn kali. Cc phng php iu tr b tr bao gm lidocain, phenytoin hay propranolol kim sot lon nhp tht v trn tht. C th phi tin hnh t mt to nhp tm thi iu tr bloc A-V nng. Cc cathecholamin l chng ch nh tng i cho nhng trng hp lon nhp tht nng v n c th lm bnh nng ln.

Thc hin sc in o nhp cho nhng bnh nhn lon nhp do ng c digitalis rt nguy him v c th gy lon nhp tht cht ngi, nu bt buc phi lm cho bnh nhn ng c digitalis c lon nhp gy ri lon huyt ng nng e do tnh mng, th nn bt u vi mc nng lng thp 10 - 20J. D sao th o nhp thng an ton hn nhng bnh nhn c nng digitalis huyt tng thp hn 2ng/ml.

Khng th khng digoxin c chn dng cho trng hp qu liu nng v ng c digoxin khng cn p ng vi iu tr. Qu liu nng digoxin c th gy ra tng K+ mu, co tht mch mc treo, thiu mu hoc nhi mu mc treo, co tht mch vnh. Cc thuc quinidin, verapamin v aminodaron lm gim s o thi digoxin, nhng bnh nhn c iu tr nhng thuc ny phi gim liu digoxin 50% trnh tng tc tng c tnh.

3. Cc thuc gin mch. 3.1. Sodium nitroprusside:

* C ch tc dng: Sodium nitroprusside l mt cht gin mch ngoi bin mnh vi hiu qu

trn c trn c tnh mch v ng mch. Tc dng xut hin ngay lp tc v ht ngay lp tc sau ngng truyn. Nitroprusside b chuyn ho ti hng cu thnh hydrocyanic v tip tc chuyn thnh thiocyanate gan ri c bi tit qua thn. Ri lon chc nng gan - thn c th nh hng ti s thanh thi thuc v ng cc cht chuyn ho ca n nh: cyanate v thiocyanide.

Nitroprusside c dng trong iu tr cp cu tng huyt p v suy tim. Nitroprusside lm gim huyt p do lm gim sc cn ng mch ngoi bin v lm tng kh nng gin ca tnh mch. Khi c suy tim, nitroprusside thng lm tng cung lng tim bng cch gim sc cn mch mu v tng th tch tng

mu, mc tng thng tim duy tr mt cung lng bng hay di mt cht ch s trc iu tr. Nhp nhanh do nitroprusside gy ra bnh nhn suy tim tri chng t l p lc y mu khng . S ci thin huyt ng trong trng hp c suy tht tri hoc tng huyt p c th c ngha c bit vi nhng bnh nhn c bnh thiu mu c tim . Nitroprussit lm gim cng c tim v v vy lm tnh trng thiu mu c tim bt i. Tuy nhin mt vi thng bo cho rng nitroprusside c th lm gim ti mu vnh vng c tim thiu mu, iu ny s nh hng n mt phn hay ton b tc dng ci thin cng c tim. Rt nhiu nghin cu xc nhn s ci thin chc nng tht tri, ti mu m, cung lng tim v tnh trng lm sng nhng bnh nhn c hi chng cung lng tim nh v sc cn mch mu ngoi bin cao. Nitroprussit c xu hng lm gim p lc ng mch phi bt nhiu hn dobutamin, do tc dng gin tnh mch v lm tng co gin tht tri mnh hn.

* Ch nh: Nitroprussit l thuc dng ng tnh mch cho trng hp tng huyt p

kch pht hoc khi cn lm gim lp tc sc cn ngoi vi. N gy gim huyt p nhanh, d iu chnh v thng dung np tt. Tc dng ca n c th nhanh chng o ngc c (nu cn) bng cch n gin l ngng truyn. Nitroprussit cng rt hu ch trong iu tr bnh nhn suy tht tri cp. C th dng n trong suy tim c huyt phi cp tnh m vic dng li tiu khng c kt qu. Trong trng hp ny kt hp gia dopamin v nitroprussit thng hiu qu hn mt thuc n c, s kt hp thuc nh th cng tng t nh tc dng ca dobutamin nhng r hn.

* Liu lng: Pha 50-100mg nitroprussit (sau khi trn bt kh vi 2 - 3ml dextrose) vo

250ml bt k loi dextrose no hoc natriclorua 0,9% v truyn tnh mch lin tc. Dung dch phi c bc kn trong v nhm hay kim loi phn quang trnh b phn hu thuc khi tip xc vi nh sng. Dung dch thuc mi pha c mu nu m nhng khng c thay i v tnh nng cu thuc. Dung dch nitroprussit lu s phn ng vi nhng mc khc nhau to thnh cc sn phm c mu m, nu n xut hin phi ngng truyn ngay. Cn s dng dung dch nitroprussit ngay sau khi pha. Tc truyn lc khi u 0,1g/kg/pht, sau iu chnh liu theo tc dng mong mun. Theo di huyt ng lin tc l rt cn thit chnh liu chnh xc khi iu tr suy tim huyt. Liu iu tr trung bnh 0,5 - 8g/kg/pht. Nitroprussit phi c truyn bng bm truyn dch m bo tc truyn chnh xc

* Ch : Khi suy tim huyt nht thit phi theo di lin tc cc ch s huyt ng

trung ng chnh liu thuc an ton v chnh xc theo mc ch s dng, phi theo di lin tc huyt p ng mch h thng. Phn ng tt huyt p l thng gp nht, khi s dng nitroprussit n c th gy thiu mu c tim, nhi mu c tim t qy, c th xut hin gim O2 mu v ri lon t s thng kh/ dng mu

phi (V/Q). Nhng bnh nhn ln tui v nhng bnh nhn c thiu khi lng mu lu hnh s nhy cm hn vi thuc v cn gim liu thp hn. Nitroprussit c th gy gim cung lng mu vnh v lm nng ln thiu mu c tim mc d n lm gim cng c tim. trng hp suy tim huyt dng nitroglycerin tnh mch c nh hng trn huyt ng tng t nh nitroprussit nhng n li ci thin tnh trng thiu mu c tim, v vy bnh nhn c bnh mch vnh ngi ta thch dng nitroglycerin hn.

Nitroprussit c chuyn ho qua gan thnh thiocyanat. Ng c thiocyanat khi dng nitroprussit t gp, tr trng hp dng liu ln (>3g/kg/pht) truyn ko di (2- 3ngy) hoc nhng bnh suy thn. Phi theo di nng thiocyanat trong cc trng hp dng liu cao, ko di hoc c suy thn. Nu nng thiocyanat trong mu nh hn10mg/100ml th vn tip tc dng c. Cc triu chng ca ng c thiocyanat gm tai, nhn m, thay i thc, bun nn, au bng, tng phn x, ng kinh. Ng c cyanide l mt bin chng him gp ngay c bnh nhn c suy gan.

3.2. Nitroglycerin:

* C ch tc dng: Nitroglycerin lm gin c trn mch mu bng cch gn vo cc th th c

hiu v to thnh cc cu disulfite. Cc loi thuc nitrat s khc nhau c bn thi gian tc dng, tnh nng, ng dng thuc. Nitrat c rt nhiu bit dc trn lm sng nhng y ch bn ti hai dng tnh mch v di li, thng c dng iu tr cn au tht ngc, nhi mu c tim cp v suy tht tri.

Nitroglycerin rt hiu qu trong iu tr cn au tht ngc. Tc dng ny thng xut hin sau 1 - 2 pht v c th ko di ti 10 pht. Trc y s p ng ny c coi nh 1 test chn on lm sng ca cn au tht ngc, song c th b nhm vi cc trng hp khc (co tht thc qun cng c p ng vi nitrat nh vy). Nitrat lm gim au ngc do gy gin c trn ca h tnh mch, n cn tr dng mu tr v ca tnh mch v gim p lc trong thnh c tim, gim cng tht tri v p lc thnh tht, ci thin ti mu di ni tm mc. Nitroglycerin cng lm gin cc ng mch vnh c ng knh ln, chng co tht mch vnh v tng tun hon bng h ti vng c tim thiu mu. Tc dng ny rt quan trng khi thiu mu c tim do ri lon vn mch ca mch vnh. Nitroglycerin di li lm gim p lc y tht tri m khng lm gim nhiu sc cn ngoi bin

bnh nhn suy tim huyt, nitroglycerin lm gim p lc y tht tri v gim sc cn ngoi bin. Gim th tch bung tht v trng lc thnh tht tm thu s lm gim nhu cu O2 c tim v gim thiu mu c tim. Tc dng r nht l tng cung lng tim. Nitroglycerin dng ng tnh mch lm gim tin gnh nhiu hn v t gim sc cn ngoi bin so vi nitroprusside. Nitroglycerin thng khng lm tng tn s tim khi tin gnh .

* Ch nh:

Nitroglycerin di li c chn trong iu tr cn au ngc. N c hiu qu i vi cn au ngc khi ngh cng nh khi gng sc. i vi au ngc, liu dng l 1 vin (0,3 - 0,4mg) di li. C th 2 ln cch nhau 5 pht. Trng hp cn gim au ngc cp, nitroglycerin c th dng di dng bnh xt, n chuyn c 0,4mg nitroglycerin mi ln xt vo di nim mc ming. Dng m bi ngoi da c th dng cho c trng hp cp v mn. Bi mt lp m nitroglycerin 2% vo vng da 3 x 6cm. Nitroglycerin dng dn khng c dng trong cp cu.

Vi cn au ngc khng n nh v nhi mu c tim, nitroglycerin tnh mch c a chung hn mc d dng ung cng c tc dng gim tn s cn au ngc khng n nh nhng thi gian bt u tc dng ca n mun hn. bnh nhn co tht mch vnh (cn au kiu prinzmetal) thng p ng tt vi nitroglycerin di li.

Nitroglycerin tnh mch c chn cho iu tr cp cu suy tim huyt c bit bnh c bnh thiu mu c tim. Nitroglycerin tnh mch v nitroprusside c cng tc dng huyt ng (gim sc cn ng mch v tng kh nng gin tnh mch). Nitroglycerin tim tnh mch c tc dng trn ng mch nhng yu hn nitroprusside. Nitroglycerin tnh mch c th gim din tch nhi mu khi iu tr nhi mu c tim c km suy tim huyt. N cng hn ch s lan rng ca nhi mu. Ngi ta khng nh rng: dng nitroglycerin mt cch thng qui s hn ch din tch nhi mu.

Nitroglycerin thng c dng vi thuc tiu ng v aspirin bnh nhn nhi mu c tim cp. N lm gim co tht mch v tr mng x va v c tc dng hip ng chng ngng kt tiu cu vi aspirin. Cc s liu nghin cu mi y ch ra rng: nitroglycerin tnh mch c th i khng vi tc dng ca heparin v lm thay i p ng ca yu t hot ho plasminogen t chc (alteplase). bnh nhn iu tr bng nitroglycerin tnh mch c hin tng gim p ng chng ng vi heparin.

Khi dng nitroglycerin bnh nhn nhi mu c tim c th gy tt huyt p, gim ti mu ng mch vnh v lm nng thm tnh trng thiu mu c tim. Nhng nu ch gim 10% (hay t hn) s huyt p ban u c xem nh l an ton bnh nhn c bnh l ng mch vnh.

* Liu lng: Khi dng di li: liu bt u 0,3 - 0,4mg, c th nhc li c mi 5 pht

cho ti tng liu 3 vin nu cn au ngc khng gim. Thuc ung t hiu qu v n b bt hot ti gan.

Nitroglycerin tnh mch: c th dng liu ln t u (bolus) hay truyn tnh mch lin tc. Khi u bng liu 12,5 - 25 g tim tnh mch, trc khi truyn tnh mch lin tc (200 - 400g/ml) vi tc 10 - 20g/1pht. Tng dn tc truyn 5 - 10g/1pht c mi 5 - 10 pht cho ti khi t c hiu qu huyt ng cng nh p ng lm sng mong mun (v d nh gim sc cn ngoi bin hoc gim p lc y tht tri, au ngc). Hu ht bnh nhn p ng vi tc 50 - 200g/pht l liu thp nht c th dng. Tu tng bnh nhn c th

dng ti liu 500g/pht. Hiu qu dc l ca n ph thuc vo th tch trong lng mch v liu lng. Nu th tch mu lu hnh gim s gim hiu qu ca thuc v tng nguy c tt huyt p. Phi dng n qua mt bm tim truyn dch m bo chnh xc liu lng v gim ti a nguy c tt huyt p.

Cn lu l nitroglycerin rt d gy ra s nhn thuc, cng tng liu cng tng hin tng nhn thuc. Nn s dng liu ngt qung vi nhng thi gian ngh thuc s gim c hin tng nhn thuc ny.

* Ch : au u l hu qu hay gp khi iu tr bng nitroglycerin. Tt huyt p gy ra

bun nn, chong vng, mt mi hoc ngt. Cc triu chng trn thng nng ln khi bnh nhn t th ng. Phi hng dn bnh nhn nm hay ngi v nn dng liu nh nht nu c th. Nn chn cao khi c tt huyt p. nhng bnh nhn dng ko di nitroglycerin th s thch nghi vi tt huyt p v au u. Tt huyt p l tc dng ph nng nht ca nitroglycerin, c bit khi c bnh l tc ng mch. Cch iu tr tt nht cc trng hp tt huyt p l gim hay ngng nitrat v b xung dch truyn. Nu c nhp chm km theo tt huyt p (phn x ph giao cm) nn iu tr bng atropin, ngng thuc v truyn dch. Phi theo di huyt ng khi truyn nhanh nitroglycerin m hiu qu an ton. N c th gy ra methemoglobin v ri lon t s thng kh/ dng mu (V/Q) gy gim O2 mu.

4. Cc thuc chn beta (propranolol, esmolol, atenolol, metoprolol): * C ch tc dng: Cc thuc chn lm mt tc dng ca cc cathecholamin tun hon trong

mu do mt kh nng gn kt vo cc th th adrenergic ca n. Propranolol, metoprolol, atenolol v esmolol c th dng ng tnh mch. Propranolol hydroclorid l mt thuc chn khng chn lc (tc dng trn c receptor 1 v 2) khng km hot tnh giao cm ni sinh. Do n l thuc chn khng chn lc nn c tc dng trn c tim (c ch sc co bp c tim v chm nhp tim) v phi (co tht ph qun). Propranolol c cng nhn l thuc iu tr nhp nhanh tht v rung tht khng tr vi cc thuc iu tr lon nhp khc gy ra do thiu mu c tim.

Metoprolol, atenolol v esmolol l cc thuc chn 1 chn lc. liu thp (

vi chn (propranolol) c tc dng nh quinidin trn mng t bo c tim v trn in th hot ng ca tim, iu lm d dng cho hiu qu chng lon nhp ca chng.

Cc thuc chn c th lm gim creatine kinase - yu t xc nh kch thc nhi mu bnh nhn nhi mu c tim cp v c th ngn nga ti nhi mu khi n c ch nh cng vi cc thuc tiu cc mu ng. Thuc chn c th bo v thiu mu c tim do tc ng mch vnh bng cch gim tiu th oxy c tim v c ch oxy ho lipid trong qu trnh ti ti mu.

Nhng hiu qu ca c ch chn lc cc v tr ca th th do cc thuc chn ph thuc khng hon ton vo s lng cc th th v nng cathecholamin tun hon trong mu.

Tim tnh mch propranolol v metoprolol to ra p ng thuc ko di 6 -8 gi. Esmolol c chuyn ho rt nhanh do ester ho bo tng ca hng cu. Thi gian bn hu n gn 9 pht (trung bnh 5 - 23 pht) v thi gian tc dng ca n gn 15 - 20 pht. Tnh chn lc tng i th th 1 ca esmolol v tc dng nhanh ca n to ra mt mc rt an ton bnh nhn nng, nhng thuc c gi thnh cao.

* Ch nh: Ch nh chnh ca cc thuc chn trong cp cu tim mch l iu tr rung

tht v nhp nhanh tht ti pht nhiu ln hay nhp nhanh kch pht trn tht khng p ng vi cc phng php iu tr khc. Cc chn hu ht l c hiu qu khi cc lon nhp ny gy ra do s kch thch qu mc ca th th - adrenergic hay do thiu mu c tim. Chng rt hu ch trong trng hp tng huyt p v nhp nhanh nu chc nng tht tri khng b gim nhiu.

Vic s dng thuc chn sau nhng triu chng u tin ca nhi mu c tim cp gim kch thc nhi mu hoc t l cht cn l vn ang c bn ci. Atenolol, metoprolol v propranolol lm gim ng k tn xut ca rung tht trong NMCTC m khng c tiu ng. Chn cng c th rt c tc dng bnh nhn iu tr bng tiu ng, khi c s dng 4 gi sau liu php tiu ng th n c th lm gim t l ti nhi mu nh v thiu mu ti pht. bnh nhn iu tr bng thuc tiu ng chn , c th lm gim t l cht v NMCT ti pht nu n c dng trong vng 2 gi sau nhng triu chng u tin. D sao i na th nhng tc dng ny ch c quan st thy nhm bnh nhn t nguy c. Tm li hin ti cha c th a ra mt khuyn co v vic dng thuc chn mt cch thng qui bnh nhn iu tr bng thuc tiu ng.

C bng chng thuyt phc l dng thuc chn ko di c th gim t l cht sau NMCTC. Nu khng c chng ch nh th cc thuc chn c khuyn co nh mt phng php iu tr phng nga t t sau NMCTC. Cn nh gi cn thn chc nng tht tri v nhng yu t bnh l i km khi mun dng thuc chn cp cu hay ngn nga lu di sau NMCTC.

* Liu lng:

Cc thuc chn ng tnh mch cn c truyn chm v theo di thng xuyn cn thn huyt p, in tm v p ng lm sng. Liu c khuyn co ca atenolol l 5mg tnh mch trong 5 pht; i 10 pht sau nu bnh nhn dung np tt th bt u ng ung vi liu 50mg; sau liu ung l 50mg x 2ln hng ngy.

Metoprolol ng tnh mch c dng vi liu 5mg trong 2 - 5pht v nhc li sau mi 5 pht n khi t c tng liu l 15mg. ng ung c bt u sau liu 50mg 2 ln/ngy trong t nht 24 gi v c tng ti 100mg x 2 ln/ngy.

Propranolol c th dng ng tnh mch liu 1 - 3mg trong 2 - 5 pht (khng vt qu 1mg/pht). Liu ny c th c lp li sau 2 pht cho ti khi t c tng liu 0,1mg/kg. Liu duy tr ung l 180 - 320mg/ngy chia 2 ln.

Esmolol c tc dng nhanh v thi gian tc dng ngn, n c dng cho trng hp cn tc dng ngn, lc ban u kim sot tn s tht bnh nhn c nhp nhanh trn tht bin i. N t nng tc dng trong 30 pht. Vic kim sot tn s cng t c trc thi gian ny, lc c th chnh tc truyn hoc ngng li. Esmolol c ng trong ng 2,5g, trc khi truyn phi pha n ti khi t c nng ti a 10mg/ml. Cch pha l cho 2,5g esmolol vo trong 250ml dch. Bt u pha truyn esmolol vi liu ln 250 -500g/kg/pht v duy tr tip theo vi liu 25 - 50g/kg/pht cho 4 pht. C mi khong 5-10 pht th chnh liu 1 ln t liu 25 - 50g/kg/pht cho n liu ti a l 300g/kg/pht.

* Ch :

Tc dng khng mong mun chnh ca thuc chn l gy tt huyt p, suy tim huyt v co tht ph qun. S dng thn trng cho nhng bnh nhn nng khi ang dng cc thuc kch thch th th - adrenergic. Khng nn dng n khi m chc nng tim suy gim v nhng trng hp sau ngng tim.

Suy tim huyt do thuc chn gy ra c th iu tr bng li tiu v gin mch, nhng thng phi dng thm cc thuc vn mch. bnh nhn c bnh l mn cm ca ng h hp, thuc chn c th gy co tht ph qun nng, thm ch t vong. Khi co tht ph qun xut hin c th iu tr bng aminophylin v cc amin giao cm. Chng ch nh dng thuc chn trong trng hp bnh nhn b bloc nh - tht hoc nhp chm nng. Atropin c th khi phc nhp tim b chm do chn gy ra. Nu nhp chm khng p ng vi atropin th cn xem xt phng php to nhp qua da, hoc truyn dopamin hay epinephrin. Isoproterenol c xem nh l gii php cui cng.

Cc tc dng khng mong mun s nng thm khi n c kt hp vi cc thuc khc c tc dng tng t (nh chn dng Ca++, cc thuc chng tng huyt p, cc thuc chng lon nhp).

sc chn thng L Xun Thc

1. i c-ng: 1.1. Vi nt lch s pht trin ca sc chn thng:

Danh t sc (shock) ln u tin c Francois Le Dran m t nm 1737. V sau nhiu tc gi b thi gian nghin cu gii thch tnh trng phn ng bnh l ny. Nhiu danh t c a ra ch tnh trng bnh l ny nh ting la tinh gi l torpor, stupor; ting c l wundschrek, traumatischer, torpor; ting Php l choc, secousse; ting Anh l shock... Ni chung trong vng 100 nm u s hiu bit v bnh l ca sc cn th s nn cch iu tr cng n gin t thu c kt qu.

Giai on mi trong lch s pht trin ca sc l t nm 1853 - 1856. Trong thi k ny xy ra cuc chin tranh Crime v c bit l cuc phng th ca cc chin s qun i Nga hong bo v pho i Sevastopon chng li qun i ng minh Anh, Php. Trong thi gian ny s lng thng binh xy ra kh ln. Cc thy thuc lc ny trn thc t nhn thy rt nhiu hnh thi khc nhau ca sc chn thng. Mt thy thuc c nhiu kinh nghim nghin cu v sc trong giai on ny l Pirogov A.I. Qua thc t quan st tnh trng bnh nhn ng m t tnh trng lm sng ca cc bnh nhn b sc tng i in hnh. Khi m cc t thi cht v sc Pirogov nhn thy c s phn b mu khng u trong cc c quan ni tng, tim trng rng, trong khi cc mch mu ln c s lng mu cha tng i nhiu hoc ngc li. Phng php iu tr lc ny l cho thng binh ung ru vang mnh, si m bnh nhn, tim thuc gim au. Pirogov cng nu ra l khng nn phu thut nhng bnh nhn m tnh trng sc cha c iu tr tt.

Nm 1867 Jorden ra vic chn on sc bng cch o huyt p ng mch v ng tin hnh cc thc nghim v sc u tin trn sc vt. Nhng thuyt v sc cng dn c hnh thnh.

+ Thuyt thn kinh: Thuyt ny c mt s tc gi ra (Pirogov, Cooper, Bilroth, Crile ...) v gii thch do tn thng ti ch cc c quan th cm th ca h thn kinh b kch thch. Cc lung thn kinh c dn ln h thn kinh trung ng gy nn tnh trng kch thch h thn kinh ni tit, to nn mt tnh trng phn ng bo v b tr ban u nh co mch, phn phi li mu tun hon, lp li p lc thm thu, iu chnh li ri lon nc v in gii khoang ngoi t bo, duy tr p lc thu tnh trong mch mu a huyt p ng mch tr li bnh thng. Giai on ny c gi l giai on sc tin pht hay sc cng. Khi cc phn ng ca h thn kinh b kit qu, cc phn ng b tr khng cn duy tr c na th sc chuyn sang giai on sc nhc. Ph hp vi thuyt ny, ngi

ta thy nhiu chin s b mt mi, thn kinh cng thng v chin u, hay lo s, cm xc qu mnh thng b sc nng khi b thng. Cc thuc gim au, thuc an thn, thuc m, hoc thuc lit thn kinh c th ngn chn hoc hn ch c qu trnh sc pht trin. Nhiu tn thng h thn kinh c pht hin trn nhng bnh nhn cht do sc. Nhng c hin tng khng ph hp l: gy t hoc gy m khng loi b c sc chn thng.

+ Thuyt tc m ca Porter (1917): Tc gi da trn thc nghim tim m vo mch mu no ca th thy xut hin tnh trng phn ng nh sc. Trn thc t ch c mt s thng binh b gip nt xng di c th gy ra tc m cn i a s ngi ta khng nhn thy nh vy.

+ Thuyt nhim c do Quenu xng (1918) : Tc gi cho sc l do s tch lu c t t cc cht hu hoi ca t bo. ng chng minh bng nhng nhn xt nhng bnh nhn sau khi tho gar. Thuyt ny khng gii thch c cc tnh trng sc khc ngoi hnh thi sc m Bywaters m t trong nhng nm 1940 - 1941 c gi l hi chng Crush (Crush Syndrome).

+ Thuyt chu k ca Moon: V khng th gii thch c tt c cc hin tng ca sc theo mt c ch thng nht nn Moon a ra mt thuyt gi l chu k Moon. Theo Moon chu k ny c 4 giai on. C th tm tt sau:

- Giai on 1: Suy tun hon c th xut hin sau mt nguyn nhn nhim c thn kinh hay mt mu.

- Giai on 2: Sc c b do cc phn x bo v nh tit cc cathecholamine t tu thng thn, tng tit cc corticoide, co lch.

- Giai on 3: Sc mt b. Cc mch mu khng cn trng lc, tun hon suy sp dn ti thiu xy cc t bo v t chc.

- Giai on 4: Vng lun qun xut hin cui cng. Thiu xy lm gii phng cc cht c, tc ng ln h thn kinh v mao mch, lm cho cc ri lon ca suy tun hon nng ln, c bit mao mch mt trng lc, dch trong lng mao mch s xut ra ngoi.

Thuyt ny c nhiu im cn ang trong giai on gi thuyt, tuy nhin n c th gii thch nhiu s kin lm sng. Qua cho thy sc l th bnh l c bit, sc khng phi l n thun, m n xen k ln nhau v c th do nhiu nguyn nhn gy nn.

+ Thuyt suy sp tun hon: khi b chn thng hay mt mu th c th c phn ng b tr bo v nh co mch, lm cho khi lng tun hon ph hp vi th tch cha cc mch mu. Tuy nhin cc phn ng tc th ny khng th ko di. Sc hay l s suy sp tun hon s xut hin khi c th mt kh nng b tr. Nguyn nhn g gy ra s suy sp tun hon . C 3 nguyn nhn c ra:

- Tng thm thu ca mao mch: Tc nhn chn thng s lm thay i tnh thm thu ca mch mu lt cc phn t c trng lng cao m bnh thng khng thot ra ngoi mch mu c (th d nh albumin, thot ra ngoi thnh mch s lm gim p lc keo trong lng mch, do nc s khng c gi trong mch mu, lm khi lng mu tun hon b thiu ht). Tnh trng ny gp trong sc bng. Truyn mu v dch c th khi phc li khi lng mu

tun hon nhng khng lm hi phc sc thm ca thnh mch c. Tuy nhin trong nhiu trng hp sc ngi ta khng thy ph n do thot dch.

- Do mt dch ti ch b thng (Domoon v Blalock xut): Mu v huyt tng thot ra ngoi ti ch b thng lm gim khi lng mu tun hon. Sc s qua 3 giai on:

. Sc tin pht: xy ra ngay sau khi b chn thng. H thn kinh ni tit b kch thch gy co mch.

. Giai on b tr.

. Giai on sc tht (mt b): Khi c ch b tr mt kh nng hot ng, khi lng mu tun hon s b thiu ht v tun hon s suy sp. Sc do mt dch ti ni b thng hay gp trong khi b thng, sau m, bng v.v... Do mt dch lm khi lng mu tun hon gim st dn ti sc. Tuy nhin c nhng trng hp mt mu khng nhiu m bnh nhn vn b sc.

- Do ri lon s phn phi mu trong h tun hon: Mu c phn phi ng cc mch mu ln hoc h tnh mch ca.

Tm tt, nhng l do trn y gii thch s suy sp tun hon gy ra sc cng khng th gii thch mt cch tho ng mi trng hp.

+ Thuyt v bnh mao mch hay l s ri lon vi tun hon do Lang xut (1945): Trc nhng chn thng c gii mnh hoc mt mu c th c phn ng t v co mch mu duy tr mc huyt p bnh thng. Phn ng ny xy ra giai on u ca sc. Do co mch nn qu trnh thiu xy mao mch xy ra trc tin. Thiu xy nn qu trnh chuyn ho cht b ri lon. Cc cht c do chuyn ha s lm cc mao mch b nhim c, gin ra v lit. Huyt tng thot ra ngoi v lm khi lng mu tun hon cng gim v mu b c c. Thuyt ny v sau c Laborit v Huguenard pht trin (1954). Cc tc gi ny cho sc trc tin gy ra bi qu trnh ri lon tun hon ngoi vi v c s tham gia trc tip hoc gin tip ca h thn kinh giao cm adrenalin. Trc nhng kch thch au c th phn ng tit ra catecholamine gy co tht cc mch mu nh v lm qu trnh thiu xy t bo xut hin. V vy 2 tc gi trn ra vic iu tr sc trc tin nn dung dch cocktail litique (thuc phong b thn kinh, gim au v khng histamin tng hp) hn ch cc kch thch ca sc v bo v c th.

Trn y ni s qua lch s pht trin ca sc v nhng thuyt nu ra gii thch tnh trng bnh l phc tp ny, nhng cha c thuyt no c th gii thch y qu trnh phn ng bnh l ny. Trn thc t cc yu t gy ra sc l phi hp (mt mu, dch, nhim c...). Nhng tng trng hp c th c yu t gy bnh tri hn ln nh hi chng vi lp th yu t nhim c l ch yu, khi b thng hoc bng th yu t mt mu, mt dch l chnh... Cho nn tu tng trng hp c th cn phi phn tch v ra bin php iu tr cho thch hp. Nhng phi nh rng d t hay nhiu cc yu t trn c phi hp vi nhau. Cho nn iu tr sc chn thng l phi iu tr tng hp.

1.2. nh ngha:

Sc chn thng l tnh trng phn ng bnh l phc tp c tnh cht giai on ca c th m tnh trng ny gy ra bi nhng chn thng c gii mnh v mt mu. Tnh trng phn ng bnh l ny biu hi