The effect of controlled respiratory rate on end-tidal co₂, arterial blood gases, and hemodynamic parameters during elective laparoscopic surgery: a comparative observational study

Background Laparoscopic surgery requires CO₂ insufflation to create pneumoperitoneum, which may lead to significant physiological changes, particularly in respiratory parameters such as end-tidal CO₂ (ETCO₂) and arterial blood gases (ABG). Intraoperative ventilation strategies, particularly respiratory rate, can influence CO₂ retention and acid-base balance. However, comparative evidence regarding optimal respiratory rates during laparoscopy remains limited. Aim To compare the effects of two controlled respiratory rates (14 vs. 20 breaths per minute) on ETCO₂ and ABG parameters in adult patients undergoing elective laparoscopic surgery. Methods This prospective comparative study included 60 adult patients scheduled for elective laparoscopic surgeries at Darwish Nazzal Governmental Hospital, Palestine, between June 2023 and January 2024. Patients were assigned to either the RR14 or RR20 group (30 patients each). ETCO₂, ABG parameters, vital signs, and peak airway pressure were measured at baseline, 15 minutes after insufflation, and post-disinflation. Data were analyzed using SPSS v23 with independent t-tests, repeated measures ANOVA, and Pearson correlation tests. Results The RR14 group showed significantly higher ETCO₂ levels than the RR20 group at all time points (p < 0.001). During insufflation, the RR14 group had higher PaCO₂ (44.08 vs. 41.28 mmHg; p = 0.004) and lower pH (7.36 vs. 7.37; p = 0.008). Longer procedure duration and higher intra-abdominal pressure were positively correlated with elevated ETCO₂ and PaCO₂ and negatively with pH. Smoking history was associated with impaired baseline respiratory values (p < 0.001). Conclusion Lower respiratory rates during laparoscopic surgery are associated with increased CO₂ retention and mild respiratory acidosis. Tailoring respiratory rate settings based on patient characteristics and intraoperative conditions may enhance physiological stability and safety.