Study outlines Pitfalls and Promises of Positive End-Expiratory Pressure in Prone Position Surgeries Under GA

During general anesthesia, for specific surgeries performed with patients in the prone position, there is often an increase in airway pressures and a decrease in pulmonary and thoracic compliance, leading to limited chest expansion. This can impact cardiac output and venous return, affecting overall hemodynamic stability. Positive end-expiratory pressure (PEEP) is utilized to alleviate these concerns by enhancing lung recruitment and ventilation and minimizing strain on the lungs. Recent study aimed to evaluate the effects of different positive end-expiratory pressure (PEEP) levels (0 cmH2O, 5 cmH2O, and 10 cmH2O) on respiratory parameters in patients undergoing spine surgery in the prone position under general anesthesia.

The study was a randomized, single-blinded, controlled trial that enrolled 90 patients scheduled for elective spine fixation surgeries. Patients were randomly assigned to one of three groups: Group A (PEEP 0), Group B (PEEP 5), and Group C (PEEP 10). Standardized anesthesia protocols were administered, with ventilation set to pressure-controlled mode at the desired PEEP levels. The key findings were: 1. Arterial oxygenation was significantly higher in Groups B (PEEP 5) and C (PEEP 10) compared to Group A (PEEP 0) at both 30 minutes post-intubation and post-extubation. Specifically, at 30 minutes post-intubation, arterial oxygenation was 142.26 ±24.7 in Group B and 154.9 ±29.88 in Group C, compared to 128.18 ±13.3 in Group A (p=0.002). 2. Mean arterial pressure (MAP) decreased significantly in Groups B and C compared to Group A. 3. Dynamic compliance was improved in Groups B and C compared to Group A. 4. Intraoperative blood loss was notably lower in Group C (329.66 ±93.93) and Group B (421.16 ±104.52) compared to Group A (466.66 ±153.76), and these differences were statistically significant.

Conclusion

These findings suggest that higher levels of PEEP (10 and 5 cmH2O) during prone positioning in spine surgery improve arterial oxygenation, dynamic compliance, and hemodynamic stability while reducing intraoperative blood loss. The study emphasizes the importance of optimizing ventilatory support to enhance patient outcomes during prone-position surgeries. Proper titration of PEEP levels is crucial to balance the benefits of improved respiratory function against potential hemodynamic effects.

Key Points

1. Arterial oxygenation was significantly higher in the groups with PEEP of 5 cmH2O (Group B) and 10 cmH2O (Group C) compared to the group with 0 cmH2O PEEP (Group A), both at 30 minutes post-intubation and post-extubation.

2. Mean arterial pressure (MAP) decreased significantly in the groups with PEEP of 5 cmH2O (Group B) and 10 cmH2O (Group C) compared to the group with 0 cmH2O PEEP (Group A).

3. Dynamic compliance was improved in the groups with PEEP of 5 cmH2O (Group B) and 10 cmH2O (Group C) compared to the group with 0 cmH2O PEEP (Group A).

4. Intraoperative blood loss was notably lower in the group with PEEP of 10 cmH2O (Group C) and the group with PEEP of 5 cmH2O (Group B) compared to the group with 0 cmH2O PEEP (Group A), and these differences were statistically significant.

5. The findings suggest that higher levels of PEEP (10 and 5 cmH2O) during prone positioning in spine surgery improve arterial oxygenation, dynamic compliance, and hemodynamic stability while reducing intraoperative blood loss.

6. The study emphasizes the importance of optimizing ventilatory support to enhance patient outcomes during prone-position surgeries, and proper titration of PEEP levels is crucial to balance the benefits of improved respiratory function against potential hemodynamic effects.

Reference -

Shanmugam Y, Venkatraman R, KY A (September 05, 2024) A Comparison of the Effects of Different Positive End-Expiratory Pressure Levels on Respiratory Parameters During Prone Positioning Under General Anaesthesia: A Randomized Controlled Trial. Cureus 16(9): e68693. DOI 10.7759/cureus.68693