Relationship between ETCO 2 and PaCO 2 under Changing Capnogram in Ventilated Infants with NAVA: An Observational Study

This observational study evaluated the validity of end-tidal CO 2 (ETCO 2 ) as a surrogate for arterial PCO 2 (PaCO 2 ) in infants on neurally adjusted ventilatory assist (NAVA), particularly considering the influence of variable spontaneous breathing on capnography waveforms. The study involved 16 infants, analyzing 50 paired ETCO 2 and PaCO 2 values. Deming regression analysis highlighted a notably stronger correlation for maximum ETCO 2 (r 2 = 0.6783, p <0.0001) compared to mean ETCO 2 (r 2 = 0.5686, p <0.0001) and demonstrated a significantly weaker association for minimum ETCO 2 (r 2 = 0.1838). These findings emphasize the superior predictive value of maximum ETCO 2 in estimating PaCO 2 , advocating its reliable use in clinical monitoring, especially given the dynamic capnography associated with NAVA's variable pressures. The results suggest ETCO 2 's potential to enhance noninvasive respiratory management, reduce the frequency of blood sampling, and improve overall care for infants requiring mechanical ventilation.