Application of end-tidal carbon dioxide monitoring via distal gas samples in ventilated neonates

Previous research has suggested correlations between the end-tidal partial pressure of carbon dioxide (P_ETCO₂) and the partial pressure of arterial carbon dioxide (PaCO₂) in mechanically ventilated patients, but both the relationship between P_ETCO₂ and PaCO₂ and whether P_ETCO₂ accurately reflects PaCO₂ in neonates and infants are still controversial. This study evaluated remote sampling of P_ETCO₂ via an epidural catheter within an endotracheal tube to determine the procedure's clinical safety and efficacy in the perioperative management of neonates.

Abdominal surgery was performed under general anesthesia in 86 full-term newborns (age 1-30 days, weight 2.55-4.0 kg, American Society of Anesthesiologists class I or II). The infants were divided into 2 groups (n = 43 each), and carbon dioxide (CO₂) gas samples were collected either from the conventional position (the proximal end) or a modified position (the distal end) of the epidural catheter.

The P_ETCO₂ measured with the new method was significantly higher than that measured with the traditional method, and the difference between P_ETCO₂ and PaCO₂ was also reduced. The accuracy of P_ETCO₂ measured increased from 78.7% to 91.5% when the modified sampling method was used. The moderate correlation between P_ETCO₂ and PaCO₂ by traditional measurement was 0.596, which significantly increased to 0.960 in the modified sampling group. Thus, the P_ETCO₂ value was closer to that of PaCO₂.

P_ETCO₂ detected via modified carbon dioxide monitoring had a better accuracy and correlation with PaCO₂ in neonates.