Heliox Adjunct Therapy for Neonates With Congenital Diaphragmatic Hernia

Congenital diaphragmatic hernia remains a complex disease with significant morbidity and mortality. Hypercarbia is a common derangement in this population, which often requires escalating ventilator support. By decreasing airway turbulence and enhancing CO₂ removal, inhaled helium-oxygen mixture (heliox) has the potential to improve ventilation and thereby decrease ventilator support and its associated lung injury.

Retrospective cohort review of all neonates with congenital diaphragmatic hernia treated at Rady Children's Hospital San Diego during 2011-2015. Clinical characteristics were compared between the infants who were treated with heliox and those who did not receive this intervention. To analyze the effect of heliox in the subgroup that received this treatment, ventilator settings and arterial blood gas values were compared before and after starting heliox by using paired t tests.

During the study period, 45 neonates with congenital diaphragmatic hernia were admitted to our neonatal ICU, 28 received heliox, and 27 were analyzed. During heliox treatment, P_aCO levels decreased from 68 to 49 mm Hg (P < .001), amplitude decreased from 33 to 23 cm H₂O (P < .001), ventilator frequency decreased from 28 to 23 breaths/min (P = .02), F_IO decreased from 0.52 to 0.40 (P < .01), and pH increased from 7.3 to 7.4 (P < .001).

The addition of heliox to the standard practice of permissive hypercapnia facilitated improvement in gas exchange, which allowed a decrease in ventilator settings and oxygen exposure, both of which are known to contribute to lung injury in this population. A prospective trial is needed to more clearly define the acute and long-term impacts of this treatment.