Research

Heliox reduces respiratory system resistance in respiratory syncytial virus induced respiratory failure

Martin CJ Kneyber^1,2 , Marc van Heerde¹ , Jos WR Twisk³ , Frans B Plötz¹ and Dick G Markhors¹

¹Department of Pediatric Intensive Care, VU university medical center, Amsterdam, The Netherlands

²Department of Pediatric Intensive Care, Beatrix Children's Hospital/University Medical Center Groningen, Groningen, The Netherlands

³Department of Biostatistics, VU university medical center, Amsterdam, The Netherlands

author email corresponding author email

Critical Care 2009, 13:R71doi:10.1186/cc7880

Published:	15 May 2009

Abstract

Introduction

Respiratory syncytial virus (RSV) lower respiratory tract disease is characterised by narrowing of the airways resulting in increased airway resistance, air-trapping and respiratory acidosis. These problems might be overcome using helium-oxygen gas mixture. However, the effect of mechanical ventilation with heliox in these patients is unclear. The objective of this prospective cross-over study was to determine the effects of mechanical ventilation with heliox 60/40 versus conventional gas on respiratory system resistance, air-trapping and CO2 removal.

Methods

Mechanically ventilated, sedated and paralyzed infants with proven RSV were enrolled within 24 hours after paediatric intensive care unit (PICU)admission. At T = 0, respiratory system mechanics including respiratory system compliance and resistance, and peak expiratory flow rate were measured with the AVEA ventilator. The measurements were repeated at each interval (after 30 minutes of ventilation with heliox, after 30 minutes of ventilation with nitrox and again after 30 minutes of ventilation with heliox). Indices of gas exchange (ventilation and oxygenation index) were calculated at each interval. Air-trapping (defined by relative change in end-expiratory lung volume) was determined by electrical impedance tomography (EIT) at each interval.

Results

Thirteen infants were enrolled. In nine, EIT measurements were performed. Mechanical ventilation with heliox significantly decreased respiratory system resistance. This was not accompanied by an improved CO2 elimination, decreased peak expiratory flow rate or decreased end-expiratory lung volume. Importantly, oxygenation remained unaltered throughout the experimental protocol.

Conclusions

Respiratory system resistance is significantly decreased by mechanical ventilation with heliox (ISCRTN98152468).