Effects of Different Levels of Positive End-Expiratory Pressure on Respiratory and Hemodynamic Changes in Laparoscopic Abdominal Surgeries

Background: Laparoscopic abdominal surgeries require carbon dioxide pneumoperitoneum for better visibility. However, it alters respiratory mechanics and may influence hemodynamic stability. Positive end-expiratory pressure (PEEP) is commonly used during mechanical ventilation to improve oxygenation by preventing alveolar collapse; however, the optimal PEEP level during laparoscopic procedures remains uncertain. This study was designed to compare the effects of 5 cmH₂O and 10 cmH₂O PEEP on respiratory and hemodynamic parameters during laparoscopic abdominal surgeries. Material and Methods: This prospective comparative study included 70 adult patients undergoing elective laparoscopic abdominal surgeries under general anesthesia. Patients were divided into two equal groups of n=35 each, the 5 PEEP group and the 10 PEEP group, based on a computer-generated random number. Hemodynamic parameters recorded were heart rate, systolic blood pressure, diastolic blood pressure, and mean arterial pressure. The recordings were done at defined time points throughout the anesthesia. The respiratory parameters recorded were peak airway pressure (P peak), plateau pressure (P plat), mean airway pressure (P mean), end-tidal carbon dioxide (ETCO₂), and arterial blood gas parameters (PaO₂ and PaCO₂). The results of the groups were compared with appropriate statistical analysis. Results: Both groups had similar Baseline demographic and anthropometric parameters. There were no significant differences in heart rate, peak airway pressure, plateau pressure, and ETCO₂ over the course of the study. The mean airway pressure was significantly elevated in the 10 PEEP group at both intraoperative time points (p≤0.001). During pneumoperitoneum, arterial oxygenation was significantly better with 10 cm H₂O PEEP (PaO₂: 177.37 ± 38.64 mmHg vs. 136.31 ± 37.84 mmHg and p<0.001), while arterial carbon dioxide levels were significantly lower at T2 and T3 (p<0.01). In the final observation, SBP, DBP, and MAP were significantly reduced in the 10 PEEP group (p≤0.001), while HR was not significantly different between groups. Conclusion: The study found that application of 10cm H₂O PEEP during laparoscopic abdominal surgeries significantly improves intraoperative oxygenation and carbon dioxide elimination without causing clinically significant changes in heart rate. Arterial blood pressure decreased slightly in this group, but haemodynamics remained stable. The results confirm that 10 cm H₂O PEEP is a successful lung-protective ventilation strategy for use during laparoscopic abdominal surgery.

Keywords: Positive End-Expiratory Pressure, Laparoscopy, Pneumoperitoneum, Mechanical Ventilation, Hemodynamics.