Validation of Continuous Transcutaneous Carbon Dioxide Monitoring in Neonates Undergoing Therapeutic Hypothermia for Neonatal Encephalopathy.

OBJECTIVE

To assess the accuracy of transcutaneous carbon dioxide (tcPCO2) monitoring compared with intermittently sampled blood gas PCO2 in neonates undergoing therapeutic hypothermia (TH).

STUDY

DESIGN

Neonates ≥34 weeks of gestation undergoing TH were enrolled and subsequently monitored with continuous tcPCO2. Agreement between tcPCO2 and both temperature-corrected and measured (uncorrected) blood gas PCO2 from arterial, venous, and capillary sources was assessed using Bland-Altman analyses that accounted for paired repeated measures.

RESULTS

One hundred thirty paired tcPCO2-PCO2 measurements were analyzed for 53 neonates. The mean difference (bias) between tcPCO2 and temperature-corrected PCO2 from all sources was 6.6 mm Hg with 95% limits of agreement from -7.4 to +20.6 mm Hg. Relative to measured PCO2, the geometric mean ratio indicated a 4% overestimation of tcPCO2, with proportional 95% limits of agreement from -25% to +35%. Capillary samples showed significant (P < .05) nonconstant variance in agreement with increasing variability at extreme PCO2 values, whereas arterial and venous samples demonstrated stable bias and variance across PCO2 ranges.

CONCLUSIONS

Using transcutaneous CO2 monitoring in infants with neonatal encephalopathy receiving TH, there is moderate agreement with wide 95% limits of agreement between tcPCO2 and PCO2 from all sources. Despite potential bias, tcPCO2 may assist in identifying trends and avoiding extreme PCO2 values during TH.

TRIAL REGISTRATION: https://clinicaltrials.gov/study/NCT04603547.