The Role of Heliox in Intensive CareThe Role of Heliox in Intensive Care

Fekri Abroug

CHU F.Bourguiba

Monastir. Tunisia

Helium + Oxygen = HelioxHelium + Oxygen = Heliox

Helium- inert low MW gas, insoluble at 1 ATM

low density (0.179 μ poise) vs. air (1.293) and O2 (1.429)

density- turbulent flow

HelioxHeliox Discovered in 1895 1934 used for airway obstruction

(Barach) Limited use if pt needs O2

Try to deliver at least 60% helium, ideally 80%

West JB, Respiratory Physiology, The Essentials, 6th ed. 2000, Lippincott, p. 91.

Heliox in acute asthmaHeliox in acute asthma

Pathophysiology in asthmaPathophysiology in asthma

Effects of HelioxEffects of Heliox

Reduces the Work of Breathing Reduces the pic pressure Reduces the dynamic hyperinflation

(auto-PEP)

7 heterogeneous studies:– 4 studies where heliox served as a vector

of nebuliserd ß2-agonists– 3 studies where heliox replaced air– 4 studies where heliox/air mixture: 80/20– 3 studies where heliox/air mixture : 70/30– Administration duration: 15-480 minutes– 6 randomised studies, 1 non randomised

PEF was not systematically corrected (1.32)

Overall: poor methodologic quality

Heliox in non-intubated Heliox in non-intubated asthmaticsasthmaticsEffects on pulmonary functionEffects on pulmonary function

Rodrigo. Cochrane Database jan 2005

Heliox in non-intubated Heliox in non-intubated asthmaticsasthmaticsEffects on hospital Effects on hospital admissionsadmissions

HelioxHeliox No effect on pulmonary function

although heterogeneous studies (trend toward favourable effect when Heliox is used for drug nebulisation)

Enhances the pulsus parodoxus in a pediatric study

No effect on admissions rate

The studyThe study evaluating Heliox in evaluating Heliox in acute asthma remains to be acute asthma remains to be

performedperformedManthous. Chest 2003Manthous. Chest 2003

Only patients without improvement following the first ß2-agonists should be included (70% of overall population improve their respiratory function followin the first bronchodilator nebulisation

The study should include a large sample size (654 patients to demonstrate a reduction in the intubation rate from 1 to 0.2% (ß=80% & α=0.05)

Heliox in the prehospital settingHeliox in the prehospital setting Baseline evaluationBaseline evaluation

PEF O2

N=97

He-O2

N=96

Mean 91.8 121.9

Median 90 110

Min / Max 0 / 300 0 / 330

PEF/ PEFtheo. O2 He-O2

Mean 21.8 28.8

Median 23.5 25.5

PEF variation (medians)PEF variation (medians)Correction (1.32)Correction (1.32)

100120

150

250

190

290

192

330

0

50

100

150

200

250

300

350

T0 T2 T3 T4

O2 (N=64)He-O2(N=67)

Heliox Acute Exacerbation of Heliox Acute Exacerbation of COPDCOPD

International Multicentric study: International Multicentric study:

NIV/ Heliox in AECOPDNIV/ Heliox in AECOPD International Multicentric Study: 2000-2002

– 5 French Centers– 1 Spanish Center– 1 Italian Center– 1 Tunisian Center

A prospective Controlled Study: Airox vs Heliox Heliox administartion duration: duration of NIV Evaluation Outcome: reduction in the intubation rate

from 40% to 20% (estimated sample size: 200)

Heliox & NIV VentilationHeliox & NIV Ventilation

Many ventilators are not calibrated for Helium and underestimate TV.

Bouton de Contrôle

Interrupteur marche/arrêt

Réglage FIO2

Touche MENU B50B50Prise O2

Détendeur Inverseur Détendeur

Héliox Héliox

Alimentation OXYGENE du 760

Bouton de Contrôle

Interrupteur marche/arrêt

Réglage FIO2

Touche MENU B50B50Prise O2

Détendeur Inverseur Détendeur

Héliox Héliox

Alimentation OXYGENE du 760

Patients characteristicsPatients characteristics

Airox

N= 99

Heliox

N=96

pH 7.28±0.06 7.28±0.07

PaCO2 71.7±15 73.3±18

SAPS II 33±11 32±11

Effects on intubation rateEffects on intubation rate

Reduction of the intubation rate: 30.3% à 20.8% (p=0.13)

RRA: 10% (95%CI: -3%-21%)

NNT: 10 (95%CI: 5-33)

0.00 0.05 0.10 0.15 0.20 0.25 0.300

10

20

30

40

50

60

70

80

90

100

Change

Po

wer

(%

)

Intubation: 20% (airox) vs 13% (heliox) Hospitalisation costs: reduction of

3348$/patient

Meta-analysis: NIV Heliox-Meta-analysis: NIV Heliox-AECOPDAECOPD

Reduction of the intubation rate: 26% to 18%(p=0.09)

ARR: 8% (95%CI: -0.8%-17%)

NNT:12(95%CI: 6-100)

Abroug &al (in press)

Greetings Greetings from from

MonastirMonastir