End tidal carbon dioxide is as reliable as transcutaneous monitoring in ventilated postsurgical neonates

Objectives To compare the agreement, precision and repeatability of end tidal carbon dioxide (Et-CO2) and transcutaneous carbon dioxide (Tc-CO2) with partial pressure of arterial CO2 (PaCOCO2) in postoperative neonates. Patients Fifty mechanically ventilated neonates without lung disease, and with no contraindications for either Tc-CO2 or Et-CO2 monitoring. Interventions Paired Tc-CO2 and Et-CO2 values were recorded with three consecutive Pa-CO2 measurements within the first 48 h of surgery. Main outcome measures Et-CO2, Tc-CO2 and Pa-CO2 triplets were compared using Bland-Altman plots. Results One hundred thirty-two triplet measures of CO2 were recorded with mean Pa-CO2 43.5 (7.3) mm Hg, Et(CO2)38.8 (6.4) mm Hg and Tc-CO2 43.8 (8.8) mm Hg (p<0.0001 for Et-CO2 against Pa-CO2; paired t test). The Pa-CO2 -Etco, bias +/- 2SD was 4.1 +/- 9.0 mm Hg and -0.8 +/- 13.0 mm Hg for Pa-CO2-Tc-CO2 56.1% of Et-CO2, and 60.6% of Tcco, values were within +/- 5 mm Hg of paired Pa-CO2. Conclusions In postoperative neonates, Et-CO2 and Tc-CO2 demonstrated a clinically acceptable agreement with Pa-CO2.