Abstract:Objective To evaluate the correlation between microstream partial pressure of end-tidal carbon dioxide (P_ETCO₂) and arterial partial pressure of carbon dioxide (PaCO₂) in patients with general anesthesia after tracheal catheter removal. Methods A total of 120 patients in Jiangsu Cancer Hospital undergoing abdominal operation under general anesthesia were selected and randomly divided into 3 groups, with 40 patients in each group. Each group received oxygen through nasal catheter at different flow rates: group L (2 L/min), group M (4 L/min) and group H (6 L/min). After 30 min of tracheal catheter removal, the value of P_ETCO₂ was recorded and arterial blood was drawn to measure PaCO₂, and the correlation between P_ETCO₂ and PaCO₂ was analyzed by Pearson. Results At 30 min of extubation, the differences in P_ETCO₂, PaCO₂, and RR among the three groups were not statistically significant (P>0.05); PaO₂ and SpO₂ in group L were significantly lower than those in groups M and H (P<0.05). There was a high correlation between microstream P_ETCO₂ and PaCO₂ in group L, M and H (r =0.931, 0.878 and 0.838, P＜0.01), and the correlation coefficients decreased with the increase of oxygen flow. Conclusion When microstream P_ETCO₂ is used to monitor patients under general anesthesia in PACU after tracheal catheter removal, there is a high correlation between P_ETCO₂ and PaCO₂ at 2-6 L/min oxygen flow, which can be used as an important reference for the evaluation of PaCO₂.