Detection of exhaled carbon dioxide following intubation during resuscitation at delivery

Objectives: End tidal carbon dioxide (ETCO₂) monitoring can facilitate identification of successful intubation. The aims of this study were to determine the time to detect ETCO₂ following intubation during resuscitation of infants born prematurely and whether it differed according to maturity at birth or the Apgar scores (as a measure of the infant's condition after birth).

Design: Analysis of recordings of respiratory function monitoring.

Setting: Two tertiary perinatal centres.

Patients: Sixty-four infants, with median gestational age of 27 (range 23-34)weeks.

Interventions: Respiratory function monitoring during resuscitation in the delivery suite.

Main outcome measures: The time following intubation for ETCO₂ levels to be initially detected and to reach 4 mm Hg and 15 mm Hg.

Results: The median time for initial detection of ETCO₂ following intubation was 3.7 (range 0-44) s, which was significantly shorter than the median time for ETCO₂ to reach 4 mm Hg (5.3 (range 0-727) s) and to reach 15 mm Hg (8.1 (range 0-827) s) (both P<0.001). There were significant correlations between the time for ETCO₂ to reach 4 mm Hg (r=-0.44, P>0.001) and 15 mm Hg (r=-0.48, P<0.001) and gestational age but not with the Apgar scores.

Conclusions: The time for ETCO₂ to be detected following intubation in the delivery suite is variable emphasising the importance of using clinical indicators to assess correct endotracheal tube position in addition to ETCO₂ monitoring. Capnography is likely to detect ETCO₂ faster than colorimetric devices.