The Role of Heliox in Intensive Care

1. The Role of Heliox in Intensive Care Fekri Abroug CHU F.Bourguiba Monastir. Tunisia

2. Helium + 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

3. Heliox • 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.

4. Heliox in acute asthma

5. Pathophysiology in asthma

6. Effects of Heliox • Reduces the Work of Breathing • Reduces the pic pressure • Reduces the dynamic hyperinflation (auto-PEP)

9. 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

10. Heliox in non-intubated asthmaticsEffects on pulmonary function Rodrigo. Cochrane Database jan 2005

11. Heliox in non-intubated asthmaticsEffects on hospital admissions

12. Heliox • 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

13. The study evaluating Heliox in acute asthma remains to be performedManthous. 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)

14. Heliox in the prehospital settingBaseline evaluation

15. PEF variation (medians)Correction (1.32)

16. Heliox Acute Exacerbation of COPD

17. International Multicentric study: NIV/ 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)

18. Heliox & NIV Ventilation • Many ventilators are not calibrated for Helium and underestimate TV.

19. Patients characteristics

20. Effects 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)

22. Intubation: 20% (airox) vs 13% (heliox) • Hospitalisation costs: reduction of 3348$/patient

23. Meta-analysis: NIV Heliox-AECOPD • 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)

24. Greetings from Monastir