BACKGROUND

Infants with hypoxic-ischemic encephalopathy are often treated with therapeutic hypothermia and high-frequency ventilation. Fluctuations in P during therapeutic hypothermia are associated with poor neurodevelopmental outcomes. Transcutaneous CO monitors offer a noninvasive estimate of P represented by transcutaneously measured partial pressure of carbon dioxide (P ). We aimed to assess the precision between P and P values in neonates undergoing therapeutic hypothermia.

METHODS

This was a retrospective chart review of 10 neonates who underwent therapeutic hypothermia requiring respiratory support over 2 y. A range of 2-27 simultaneous P and P pairs of measurements per neonate were analyzed via linear mixed models and a Bland-Altman plot for multiple observations per neonate.

RESULTS

A linear mixed-effect model demonstrated that P and P (controlling for sex) were similar. The 95% CI of the mean difference ranged from -2.3 to 5.7 mm Hg ( = .41). However, precision was poor as the P ranged from > 18 mm Hg to < 13 mm Hg than P values for 95% of observations.

CONCLUSIONS

The neonates' P was as much as 18 mm Hg higher to 13 mm Hg lower than the P 95% of the time. Transcutaneous CO monitoring may not be a good trending tool, nor is it appropriate for estimating P in patients undergoing therapeutic hypothermia.