Anaesthesia for laparoscopic nephrectomy: Does end-tidal carbon dioxide measurement correlate with arterial carbon dioxide measurement?

Abstract

Background and Aims: Not many studies have explored the correlation between arterial carbon dioxide tension (PaCO2) and end-tidal carbon dioxide tension (ETCO2) in surgeries requiring pneumoperitoneum of more than 1 hour duration with the patient in non-supine position. The aim of our study was to evaluate the correlation of ETCO2with PaCO2in patients undergoing laparoscopic nephrectomy under general anaesthesia. Methods: A descriptive study was performed in thirty patients undergoing laparoscopic nephrectomy from September 2014 to August 2015. The haemodynamic parameters, minute ventilation, PaCO2and ETCO2measured at three predetermined points during the procedure were analysed. Correlation was checked using Pearson's Correlation Coefficient Test. P <0.05 was considered statistically significant. Results: Statistical analysis of the values showed a positive correlation between ETCO2and PaCO2(P < 0.05). Following carbon dioxide insufflation, both ETCO2and PaCO2increased by 5.4 and 6.63 mmHg, respectively, at the end of the 1st hour. The PaCO2-ETCO2gradient was found to increase during the 1st hour following insufflation (4.07 ± 2.05 mmHg); it returned to the pre-insufflation values in another hour (2.93 ± 1.43 mmHg). Conclusion: Continuous ETCO2monitoring is a reliable indicator of the trend in arterial CO2fluctuations in the American Society of Anesthesiologists Grades 1 and 2 patients undergoing laparoscopic nephrectomy under general anaesthesia.

Keywords

• Blood gas monitoring
• capnography
• carbon dioxide partial pressure determination
• pneumoperitoneum