Evaluation of Arterial to End-tidal Carbon Dioxide Pressure Differences during Laparoscopic Renal Surgery in the Lateral Decubitus Position

Shalvi Mahajan; Rajeev Chauhan; Ankur Luthra; Indu Bala; Neerja Bharti; Ashish Sharma

doi:10.4103/aer.AER_88_19

Evaluation of Arterial to End-tidal Carbon Dioxide Pressure Differences during Laparoscopic Renal Surgery in the Lateral Decubitus Position

Anesth Essays Res. 2019 Jul-Sep;13(3):583-588. doi: 10.4103/aer.AER_88_19.

Authors

Shalvi Mahajan¹, Rajeev Chauhan², Ankur Luthra², Indu Bala², Neerja Bharti², Ashish Sharma³

Affiliations

¹ Department of Anaesthesia and Intensive Care, Fortis Hospital Mohali, Chandigarh, India.
² Department of Anaesthesia and Intensive Care, PGIMER, Chandigarh, India.
³ Department of Renal Transplant Surgery, PGIMER, Chandigarh, India.

Abstract

Background: End-tidal carbon dioxide (PEtCO₂) is a noninvasive reliable technique to measure arterial partial pressure of carbon dioxide (PaCO2) in the body under general anesthesia. However, gradient between PaCO₂ and PEtCO₂ (P[a-Et] CO₂) is influenced by many factors.

Aims: In the present study, we evaluated the changes in P (a-Et) CO₂ for laparoscopic donor nephrectomy in lateral decubitus position (LDP).

Settings and design: This was an observational, double-blinded, tertiary care center-based study.

Methods: Thirty-one American Society of Anesthesiologists Class I and Class II patients of either sex undergoing laparoscopic donor nephrectomy in LDP under general anesthesia were included. An arterial cannula was inserted, PaCO₂ was measured at eight predesignated time intervals, and PEtCO₂ was also noted at the corresponding time period.

Statistical analysis: Data were analyzed using a two-way analysis of variance for repeated measurements using one dependent variable and one within-subject factor (time). Quantitative data were presented as mean ± standard deviation or median and interquartile range, as appropriate.

Results: The mean P (a-Et) CO₂ gradient was 5.67 ± 1.36 mmHg 10 min after induction of anesthesia in the supine position (T1a). Ten minutes after LDP, P (a-Et) CO₂ gradient was 7.38 ± 1.45 mmHg (T1b) and was higher than T1a. The P (a-Et) CO₂ values 10 min after release of pneumoperitoneum and 10 min after making the patient supine were significantly higher than the T1a value. The highest value of P (a-Et) CO₂ gradient was at 30 min after creation of pneumoperitoneum (T30), i.e., 9.99 ± 1.70 mmHg. Pearson's correlation coefficient showed that the degree of correlation varied considerably during surgery due to interindividual variability (R ² T1a vs. T60 was 0.61 vs. 0.17).

Conclusions: PEtCO₂ does not reliably predict PaCO₂ in healthy patients scheduled for laparoscopic renal surgery in LDP.

Keywords: Carbon dioxide; laparoscopic surgery; lateral decubitus position; partial pressure; pneumoperitoneum.