Exhaled Carbon Dioxide Monitoring Using Instantaneous CO2 Mode During High-Frequency Oscillatory Ventilation in Very Low Birth Weight Infants.

BACKGROUND: High-frequency oscillatory ventilation (HFOV) presents challenges for noninvasive CO2 monitoring due to its rapid oscillations. This study examines the feasibility of instantaneous CO2 partial pressure (INST CO2) monitoring during HFOV with a capnometer equipped with a mainstream CO2 sensor. METHODS: This study included seven neonates receiving HFOV in the neonatal intensive care unit (NICU) at Shizuoka Children's Hospital. INST CO2 values were recorded over 3- and 5-min intervals surrounding each blood gas sampling to determine the maximum INST CO2 value (INST CO2 MX). The primary outcome was the correlation between INST CO2 MX and arterial partial pressure of carbon dioxide (PCO2). RESULTS: A total of 216 paired INST CO2 MX and PCO2 values were analyzed. The coefficient of determination (R2) was 0.571 for INST CO2 MX (3 min) and 0.579 for INST CO2 MX (5 min). Univariable and multivariable analyses revealed that a lower fraction of inspired oxygen (FiO2), reduced minute ventilation, and increased postnatal age were associated with improved concordance between INST CO2 MX and PCO2. CONCLUSION: INST CO2 MX demonstrated a strong correlation with PCO2 in neonates undergoing HFOV. This novel, noninvasive monitoring approach may serve as a valuable tool for neonatal respiratory management. Future research is needed to validate these findings in broader patient populations and across various ventilatory settings.