Relationship between Arterial and End-Tidal Carbon Dioxide Pressure during Controlled Ventilation in Porcine Neonates

Abstract

To investigate the validity of ETCO2 in porcine neonates, which have been frequently used as an experimental model for human neonates, the relationship between arterial (PaCO2) and end-tidal PCO2 (ETCO2) in porcine neonates was examined under different respiratory conditions by regulating both inspiratory flow and positive end expiratory pressure (PEEP). The difference between PaCO2 and ETCO2 widened significantly, according to the significant decrease in tidal volume/body weight ratio (TV/BW) caused by the increase of PEEP. A lower correlation between PaCO2 and ETCO2 was observed in <6 ml/kg than in ≥6 ml/kg TV/BW. It therefore seems reasonable to conclude that, in porcine neonates, the valid ETCO2 measurements corresponding to PaCO2 would be obtained at ≥6 ml/kg TV/BW.