Laparoscopic Surgery : anaesthetic implication

Dr Saurav Das

INTRODUCTION

• Laparoscopy ( Greek λάπάРά =flank or λάЛάРОδ =soft σκОЛήтν = to look) has revolutionized surgical procedures because of the important advantages it offers namely less tissue trauma,decreased post operative pain as well as shorter hospital stay with minimized post operative morbidity and mortality.

• Gyanecological laparoscopic surgery has been started since 1970’s.In 1987, Phillipe Mouret described the first laparoscopic cholecystectomy in France.Literature about low IAP and modern anaesthetic technique has started publishing after 1990’s.

ROUTINELY DONE LAPAROSCOPIC SURGERIES

• 1)Cholecystectomy• 2)Vagotomy• 3)Hiatus hernia repair• 4)Diaphragmatic hernia repair• 5)Appendectomy• 6)Colectomy• 7)Inguinal hernia repair• 8)Nephrectomy• 9)Adrenalectomy for phaechromocytoma• 10)many gynecological procedures

Benefits of laparoscopic surgery:• It can summarized as follows:• 1)Minimal abdominal incision• 2)Less metabolite derangements• (studies have confirmed the reduced metabolite

derangement by measuring interlukin 6 level and c reactive protein ).

• 3)Reduced adverse effect • 4)Better postoperative pulmonary function test

• 5)Less postoperative illeus due to less tissue handling ,so oral feeding can be started early .

• 6)Less postoperative pain .

• This all leads to early ambulation .

• Shorter hospital stay .

• Early return to work and normal activity .

SPECIAL CHARACTERISTIC OF LAPAROSCOPIC SURGERY

• Laparoscopic surgery,although enjoying ever increasing popularity present view anaesthetic challenges because of

• Carbondioxide insufflation to produce pneumoperitoneum

• Position of the patient that is trendelenburg and reverse trendelenburg

CHANGES DUE TO PNEUMOPERITONEUMPneumoperitoneum is created by insufflation of gases

through verses needle at @ 1-2 lit /min .

• Once pmeumoperitoneum is achieved ,over all pressure over the diaphragm is almost 50 kg.( in trendelenburg position at an IAP of 15mmhg )This results in following respiratory changes:

• Decreased Tidal and so Minute volume• Decreased FRC• Increased PAW

• Increased risk of barotrauma during IPPV

METABOLIC CHANGES

• During an uneventful CO2 pneumoperitneum ,PCO2 rises till it reaches a plateau at 15 to 30 min after insufflation .Rise of PCO2 is mainly due to peritoneal absorption. Some other factors which also contributes to raise PCO2 are :

• Va/Q mismatch – increased physiologic dead space due to• *abdominal distension• *position of patient (steep head down)• Controlled mechanical ventilation • Reduced cardiac output• (All these mechanism are attenuated in sick person like obese ,ASA2 and ASA3 )• Increased metabolism• Insufficient plan of anesthesia• Transfusion of more glucose containing fluid• 3. Depression of ventilation by anesthetics in case spontaneous breathing• 4. Accidental event• CO2 emphysema• Capnothorax• CO2 embolism•

• Changes of PACO2, PETCO2 and PH attain a plateau after 15 to 30 mins after insufflation . Any change there after requires a search for a cause

CARDIOVASCULAR CHANGESThese changes are characterized by :

Decreased cardiac outputElevation of arterial pressure and pulmonary vascular resistance

HR may decrease or increase

• G I T CHANGES:• Patient under going laparoscopy are considered at high risk

acid aspiration syndrome .I t might be due to increased intragrastic pressure consequent to Increased IAP .

• MESENTERIC CIRCULATION:• The visceral vascular bed is the primary site of compression

during raised IAP resulting in organ dysfunction .Other contributing factor sympathetically mediated vasoconstriction and mechanical compression of abdominal organ.

• HEPATORENAL CIRCULATION:• Increase IAP adversely affects the portal vascular

resistance. An IAP > 20mmhg decreases portal blood flow by 60% resulting liver dysfunction may persist for a prolong period.

• RENAL DYSFUNCTION:• Urine output. Renal blood flow and GFR decrease to

less than 50% of base line value .Urine out put increases significantly after desufflation

• CERBRAL BLOOD FLOW :• Both ICP and IOP are raised due to vasodialating action of CO2 . In

normal individual these changes are tolerable but in patient with SOL or glaucoma may show some deleterious effects .

• HYPOTHERMIA:• During laparoscopy continuous flow of dry gases over peritoneal surface

under pressure can lead to fall of core body temperature .ie joule Thompson effect . some aggravating factors are higher flow rate ,prolong duration of surgery, leakage through port ,peritoneal lavage etc .

• There is 0.30 c fall in core temperature per 50l volume flow of carbondio• xide .

CAN LAPAROSCOPY BE PERFORMED IN ALL PATIENT ???????

• Following groups of patient need careful consideration :

• Patient with in ICP , SOL and CVA • Patient having ventriculoperitoneal and

juguloperitoneal shunt .• Hypovolumic patient • Patient with cardiac disease

• Patient with renal dysfunction.

• Patient with h/o of deep vein thrombosis .

Anaesthetic management • Anaesthetic goals:

• Hemodynemic stability• Respiratory stability• Adequate muscle relaxation• Control of diaphragmatic excursion• Intra and post operative analgesia• Control of PONV• Deep vein thrombosis prophylaxis• Protection against hypothermia

Monitoring during laparoscopic surgery

• Recommendation for routine patient monitoring:• Pulse rate• Continuous ECG• Intermittent NIBP• SPO2• Capnography• Temperature• IAP• PAW

Optional monitoring include

• Esophageal Stethoscope

• Precordial Doppler

• Trans-esophageal echocardiography

• Arterial blood gas analysis

• Most importantly a vigilant anesthetist

Technique of anesthesia • General anesthesia with endotracheal intubations and controlled ventilation is the safest

technique and therefore is recommended for long laparoscopic procedure • Atropine is administered at the time of induction to prevent bradycardia .• The choice of anesthetic technique does not seem to play a major role in patient’s outcome.• Adequate abdominal and diaphragmatic muscle relaxation is essential• Rapid sequence induction with suxamethonium is recommended in anti reflux surgery• Due to raised IAP and increase in the mechanical ventilation pressure is required to achieve

adequate ventilation.Normocarbia is maintained by increasing respiratory rate.• Following induction the patient is catheterized to empty urinary bladder and nasogastric tube is

inserted to avoid stomach injury.• Insufflations flow rate should be low, initially 1-1.5 Ltr/min.• Use of nitrous oxide(N2O) is controversial for maintenance of anesthesia because of concern

about its ability to produce bowel distension during surgery and PONV.• Halothane in the presence of hypercarbia can cause arrhythmia.• The position of ET tube to be checked repeatedly because of the likelihood of endobronchial

intubatiion.

Regional anaesthesia(Epidural/ Spinal /CSE)

• Advantages:• Early diagnosis of complication. • During a creation of pneumoperitoneum, patient breathing spontaneously under

epidural anesthesia results in increased minute ventilation with unchanged ET CO2.

• Provides excellent post-operative analgesia with low incidence of PONV.• Fewer hemodynamic changes due to absence of positive pressure ventilation• • Disadvantages:• Increase anxiety, pain, discomfort of the patient during manipulation.• Supplemental sedation can depress respiration, sensitivity to CO2 and hypoxia.• Shoulder tip pain from diaphragmatic irritation and discomfort from abdominal

distention are incompletely alleviated

Intraoperative complication:

• 1. Trochar may cause abdominal vessel injury, GIT perforation, hepatic and splenic tear and omental injury.

• Hassen minilaparotomy technique has been advocated for pneumoperitoneum creation .

•

• 2. Extraperitoneal insufflation of CO2 is a common complication of laparoscopy.ET CO2, VCO2 and PACO2 all increases more than expected.

• Once diagnosed, insufflation should be stopped and ventilation should be continued to wash out extra CO2.

• 3) Pneumothorax pneumomediastinum and pneumopericardium :-

• Causes :- Trespass of gases through embryonic remnants , defects in diaphragm, weak points in aortic and esophageal hiatus.

• Rupture of emphysematous bullas .• By pleural tear caused by surgical tear.

It can be diagnosed by

• Progressive hypoxemia ,increasing paw and subcutaneous emphysema.

• Observation of abnormal motion of diaphragm by laparoscopist

• By auscultation• Chest x ray• With out any associated pulmonary trauma this condition

resolve after 15 to 30 mins after exsufflation.

The recommended guidelines are as follows

• Stop N2O• Adjust ventilation to correct hypoxaemia• Apply PEEP• Maintain close communication with surgeon• Avoid thoracocentesis unless necessary• In case of pneumothorax from rupture of pre existing

bullae ,PEEP must not be applied and tharococentesis is mandatory

ENDOBRONCHIAL INTUBATION

• Cephald displacement of the diaphragm during pneumoperitoneum result in cephald movement of carina leading to endobronchial intubation

GAS EMBOLISM• Causes are –• Direct insufflation of gas into a vessel by misplaced

trochar or veress needle.• Small bubble of gas carried through injured vein at

operative site• Large gas absorption into portal circulation may be

caused by very fast rate of gas flow and very high intra abdominal pressure.

Suspicion of gas embolism • To be aroused by • Hypoxaemia• Hypotension• Tachycardia• ECG changes of rt hart strain• Jugular Turgescenc• Circulatory collapse• If paradoxical cerebral embolism occurs ,signs are:• Immediate – Bilateral Mydriasis• At the of anesthesia –comma, delayed awakening, seizures, paresis or

paralysis

Diagnosed by • Precordial or esophageal stethoscope : Metallic murmur heard

2to3 sec. after gas inflow. With increasing volume typical Mill Wheal murmur appears

• Precordial Doppler can detect 2 ml of gas• Swan ganz catheter detects haemodynemic changes at earliest• Capnograph Its response is biphasic :- • Small volume of gas gives high ETCO2 due to high Vco2• Large volume makes ETCO2 falls rapidly for low CO

Early and energetic management of air embolism

• Stop insufflation immediately • Release pneumo peritoneum• Place pt in Durant position• Hyperventilate• Increase FIo2• Stop N2O – it helps bubble resorbtion• Insert central venous catheter to aspirate gas or foam• Haemodynemic support• External cardiac message to breaks the air bubble• If all fails,Cardio pulmonary by pass and internal cardiac compression.

• CARDIAC ARYHTHMIAS

• Patient undergoing laparoscopy are prone to develop cardiac arrythmias due to high PCO2 and raised vagal tone .

POST OPERATIVE PROBLEMS

• Incidence of post operative sickness is significant , may be due to peritoneal stretching & hypercapnia

• Significant pain occur in first 24 hr period• Hypothermia during recovery• Hypoxia after recovery• Post operative shoulder pain may be agonizing. It may be

due to intra pleural H2CO3 which goes on dissociating to CO2

CARE FOR PREVENTION POST OPERATIVE PROBLEMS

• O2 administration for couple of hours to prevent alveolar hypoxia as CO2 excretion continues

• Energetic care for prevention of sickness must be taken as PONV can jeopardize all the benefits of laparoscopy and anesthesiologist gets total blame .

• Proper warming of patient.• Attention must be paid for pain relief.

FUTURE TRENDS:

.• INERT GASES : Use of inert gases like helium ,argon can reduce

hypercarbia but other changes due to increased IAP remain same .Since solubility of these gases is low, there is always a chance of gas embolism.

• GASLESS LAPAROSCOPY:Here the peritoneal cavity is lifted with an abdominal fan retractor. Combined this technique with low IAP(<5mm of Hg) is an interesting prospect this technique avoids hemodynamic and respiratory repercussions. Post operative PONV and port site metastasis are reduced. This thing is very appealing in severe cardiac and pulmonary diseases.Disadvantages are difficult techniques and poor surgical site.

Summary• Despite multiple advantages, Laparoscopy is not a

synonym for risk free operation. The death rate during laparoscopic surgery is 0.1 to 1 per 1000 cases. Anesthesiologist must be aware, able to detect and manage those life threatening complication. .Capnography is one of the most important tool to tackle these complication and every one should know how to interrelate ETCO2 with other important findings

CO2 remains the insufflation gas of choice because of –

• Its readily availability• Low cost• A high ostwald blood / gas partion co efficient makes it

highly soluble in blood. So the gas embolism is rare.• Non combustible.• rapidly buffered in the blood by bicarbonates and excreted

via lungs

• Patient with cardiac disease • If patient cardiac disease is planned for laparoscopy following protocol should be followed :• Preoperative evaluation• Echocardiography to see cardiac function .if left ventricular ejection fraction is <20mmhg, following

intra operative monitoring are mandatory • Intra arterial line• Pulmonary artery catheter• Trans esophageal echocardiography• Continuous ST segment analysis• Intra operative management• Slow insufflation• Low IAP• Patient tilt after operation .• Post operative care :• Slow recovery from anesthesia

Agent used for insufflations

Ostwald blood/gas coefficient

Flammability Risk of explosion

Nitrogen 0.061 Explosive High

Oxygen 0.031 Non inflammableSupports combustion

High

Carbon dioxide 0.871 Non inflammable Low

Nitrous oxide 0.47 Non inflammableSupports combustion

Moderate

Helium Non inflammable High

Xenon 0.14 Non inflammable High