The recent randomized controlled trial by Xue, et al. [1] aims at
reducing the length of ventilation as primary aim. The authors have also
looked into lung inflammatory markers like Interleukin-6, which was
positively correlated with the length of ventilation but was not proved
significant.
Heliox gas flows in laminar fashion creating less
resistance because of its property of low density and lower Reynolds
number which thereby helps in gas exchange and reduced work of
breathing, particularly in disease states where there is evidence of
airway obstruction [2,3]. It is still unclear how heliox helps in
improving outcome in respiratory distress syndrome; the possible
explanation other than reducing lung inflammation is improving
oxygenation and carbon dioxide elimination and thereby improving the
blood pH and reducing pulmonary hypertension.
The participants in this study were mid-late
premature infants (mean gestation 34 weeks); many ongoing/completed
trials aim to assess interventions for reducing morbidity, particularly
chronic lung disease, in preterm cohorts born earlier than 34 weeks.
Reduction in length of ventilation in this study cohort may not be too
great as these babies generally require short term ventilation.
Moreover, heliox is likely to be a costly intervention; the reported
cost is 750€ for 12 hours of treatment [4].
The authors have concluded that nasal intermittent
positive pressure ventilation might have increased the efficacy of
delivering heliox, as an earlier study [4] failed to show reduction in
length of ventilation when CPAP was used. The population in the earlier
trial was more premature (30 weeks) and the reduction in the length of
ventilation was not the primary objective. Practically, heliox reduces
the increasing oxygen requirement by effective delivery of gas thereby
decreasing the threshold for surfactant/ventilation and is unlikely to
affect the length of ventilation. We suggest that the utility of heliox
should be tested in more immature infants with the objective to reduce
chronic lung disease and other morbidity.
1. Li X, Shen J, Zhao J, Tang S, Shi Y. Nasal
intermittent positive pressure ventilation with heliox in premature
infants with respiratory distress syndrome: A randomized controlled
trial. Indian Pediatr. 2014;51: 900-2.
2. Myers TR. Use of heliox in children. Respir Care.
2006;51:619-31.
3. Gupta VK, Cheifetz IM. Heliox administration in
the pediatric intensive care unit: An evidence-based review. Pediatr
Crit Care Med. 2005;6:204-11.
4. Colnaghi M, Pierro M, Migliori C, Ciralli F, Matassa PG,
Vendettuoli V, et al. Nasal continuous positive airway pressure
with heliox in preterm infants with respiratory distress syndrome.
Pediatrics. 2012;129:e333-8.