The accuracy of transcutaneous carbon dioxide monitoring during laparoscopic surgery

BACKGROUND: Laparoscopic procedures are considered relatively low-invasive. However, there exists a small but important risk of developing complications related to carbon dioxide (CO2) insufflation. End-tidal CO2 (PetCO2) monitoring may not be a sufficient guide to adjust pulmonary ventilation during laparoscopic surgery, and arterial CO2 (PaCO2) monitoring is not always indicated. We evaluated the accuracy and feasibility of transcutaneous CO2 (PtcCO2) monitoring during laparoscopic surgery. METHODS: Thirty adult patients undergoing abdominal or gynecological laparoscopic surgery were studied. PtcCO2, PaCO2 and PetCO2 were measured before laparoscopy, and 30 and 60 minutes after beginning of CO2 insufflation. PtcCO2 and PaCO2 were also measured in the recovery room under spontaneous respiration. RESULTS: During operation, the PtcCO2 values demonstrated a high degree of correlation with PaCO2 (r = 0.92), and PetCO2 values also demonstrated generally a good correlation with PaCO2 (r = 0.85). The PtcCO2 PaCO2 gradient was -0.6 +/- 2.2 mmHg, while the PetCO2-PaCO2 gradient was -3.9 +/- 2.7 mmHg. In the recovery room, PtcCO2 values still demonstrated a high correlation with PaCO2 (r = 0.91). CONCLUSIONS: The transcutaneous devices provide an effective method for non-invasive monitoring of PCO2 in situations where continuous monitoring of CO2 levels is desired such as peri-operative period of laparoscopic surgery.