Agreement of Carbon Dioxide Levels Measured by Arterial, Transcutaneous and End Tidal Methods in Preterm Infants ≤28 Weeks Gestation

OBJECTIVE: To assess the agreement of transcutaneous carbon dioxide (TcPCO 2 ) and end tidal carbon dioxide (PetCO 2 ) with arterial carbon dioxide (PaCO 2 ) values in infants < 28 weeks gestational age. STUDY DESIGN: In all, 27 ventilated preterm infants were prospectively studied. PaCO 2 was compared with TcPCO 2 and PetCO 2 measured at three similar time points within first 24 hours after birth. RESULTS: The Intraclass correlation coefficients for TcPCO 2 and PaCO 2 were 0.45, 0.73 and 0.53; and for PetCO 2 and PaCO 2 were 0.61, 0.56 and 0.57 at 4, 12 and 24 hours after birth, respectively. CONCLUSION: A moderate agreement with a wide variation in individual values was observed between noninvasive methods and PaCO 2 in preterm infants in the first 24 hours. Noninvasive monitoring methods cannot be substituted for PaCO 2 analyses in preterm infants during this critical period.