Heliox Adjunct Therapy for Neonates With Congenital Diaphragmatic Hernia

BACKGROUND

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.

METHODS

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.

RESULTS

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_aCO2 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_IO2 decreased from 0.52 to 0.40 (P < .01), and pH increased from 7.3 to 7.4 (P < .001).

CONCLUSIONS

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.

Acanthosis nigricans-like hyperpigmentation secondary to triazinate therapy

Cutaneous hyperpigmentation resembling acanthosis nigricans developed in two patients with malignant brain tumors following chemotherapy with triazinate (Baker's Antifol), a folic acid antagonist. In both cases, the eruption resolved after the cessation of drug administration and reappeared after the reinstitution of triazinate therapy. A skin biopsy specimen from one patient showed microscopic changes consistent with those found in acanthosis nigricans. The other patient had a decreased serum folate level that returned to normal as the hyperpigmentation resolved. Folate may have a role in triazinate-induced acanthosislike hyperpigmentation.