Accuracy of a battery-powered portable capnometer in premature infants

Carbon dioxide measurement is useful for confirmation of successful tracheal intubation and ensuring adequate ventilation. There are two types of CO(2) detectors, i.e., single-use-only colorimetric devices and capnometers. Although portable capnometers are widely used for resuscitation, there have been no reports regarding their clinical utility in neonates. The correspondence between end-tidal CO(2) (PetCO(2)) level determined using a battery-powered portable capnometer and arterial CO(2) (PaCO(2)) was investigated using paired data obtained simultaneously from 26 neonates weighing 1262 ± 589 g at examination on mechanical ventilation. PetCO(2) level and PaCO(2) showed a strong correlation (r = 0.839, P < 0.001), and the correlation equation was: PetCO(2) = 0.8 × PaCO(2) + 1.1. Therefore, PetCO(2) readings obtained with a battery-powered portable capnometer were likely to be underestimated. This became more pronounced with decreasing infant body weight at examination as the net difference in measurements of PaCO(2) and PetCO(2) was significantly positively correlated with infant body weight at examination (r = 0.451, P < 0.001). The observations presented here may be helpful in the use of battery-powered portable capnometers in neonates requiring controlled ventilation with tracheal intubation.