Application value of monitoring of percutaneous partial pressure of carbon dioxide/oxygen for patients in ICU after general anesthesia

Abstract

For patients in ICU under mechanical ventilation, monitoring of percutaneous partial pressure of CO2 and O2 after general anesthesia is crucial as excessive or insufficient ventilation may prove to be fatal. However, the correlation between percutaneous monitoring and arterial blood gas analysis still remains unclear. Here, we studied the application value of monitoring of PtcCO2/PtcO2 for patients in ICU after general anesthesia for better management of patients in ICU on ventilation. A total of 195 eligible patients were selected. After transfer, when PtcCO2 and PtcO2 were stable (10-15 min), they were recorded as transfer-in values. Partial pressure of carbon dioxide (PaCO2), partial pressure of oxygen (PaO2), lactate, PtcO2 and PtcCO2 were recorded. Vital signs and hemodynamics data were also recorded. There were significant positive correlations between PtcCO2 and PtcO2 (r = 0.876), and between PtcO2 and PaCO2 (r = 0.817) (P <0.01). PaO2 was higher than PtcO2 (P <0.01). There were significant positive correlations between PtcCO2/PtcO2 and PaCO2/PaO2 at different time points (T0: upon transfer-in; T1: before extubation; T2: upon transfer-out, P <0.01). At different oxygen inhalation concentrations (21, 40 and 50%), PtcCO2 and PtcO2 were all well linearly correlated. The overall PtcO2/PaO2 was (0.75±0.12). When FIO2 values were 21, 40 and 50%, PtcO2/PaO2 values were similar (P >0.05). PtcCO2 and PtcO2 or PtcO2 and PaCO2 are significantly positively correlated, without significant differences between different time periods or oxygen concentrations. PtcCO2 and PtcO2 can predict the changes of PtcO2 and PaCO2, which is of great significance to the early observation of oxygenation changes, adjustment of ventilator parameters and improvement of prognosis. PtcCO2/PaO2 values are similar at different oxygen concentrations, as an eligible index for the postoperative evaluation of tissue perfusion status and hemodynamic level.