Accuracy of a battery-powered portable capnometer in neonates

Abstract End-tidal CO 2 measurement (EtCO 2 ) is useful for confirmation of successful tracheal intubation and ensuring adequate ventilation. There are two types of EtCO 2 detector, i.e., single-use-only devices and capnometers. Although portable capnometers are widely used for resuscitation, there have been no reports regarding their clinical utility in neonates. Here, the correspondence between EtCO 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. EtCO 2 level and PaCO 2 showed a strong correlation (r = 0.839, P < 0.001), and the correlation equation was: EtCO 2 = 0.8 × PaCO 2 + 1.1. Therefore, EtCO 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 EtCO 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.