The Effect of Positive End-expiratory pressure (PEEP) on Postoperative Pulmonary Complications and Mortality in Major Abdominal Cancer Surgery

INTRODUCTION: Postoperative pulmonary complications (PPCs) significantly contribute to morbidity and mortality, particularly in patients undergoing major abdominal cancer surgery. Bronchospasm, atelectasis, pneumonia, and respiratory failure occur more frequently in cancer patients due to immunosuppression, reduced physiological reserves, and surgical complexity. Positive end-expiratory pressure (PEEP) is used during mechanical ventilation to reduce atelectasis and improve lung compliance; however, its effect on PPCs and mortality remains unclear. This study aims to investigate the relationship between PEEP levels, PPC occurrence, and their impact on mortality rates.
METHODS: In this retrospective study, 410 patients who underwent major abdominal cancer surgery between January 2019 and December 2020 were analyzed. Patients were divided into two groups based on intraoperative PEEP levels: Group 1 (0-5 cm H2O PEEP) and Group 2 (6 cm H2O and above). Patient demographics, including age, sex, ASA scores, duration of surgery, body mass index (BMI), administered PEEP values, ARISCAT scores, as well as preoperative SpO2 and hemoglobin levels were documented, and their association with PPC was analyzed using appropriate statistical methods.
RESULTS: The overall PPC rate was found to be 12%, with a significantly higher incidence in Group 2 (23%) compared to Group 1 (9%) (p<0.05). However, no significant difference in 30-day mortality was observed between the two groups (p>0.05). Additionally, co morbidities and preoperative pulmonary dysfunction were strongly associated with an increased risk of PPCs.
DISCUSSION AND CONCLUSION: Although lung-protective strategies like low tidal volume and PEEP are commonly recommended, the findings indicate that higher PEEP levels might be linked to a higher incidence of PPCs, possibly due to hemodynamic instability. However, no definitive correlation between PEEP levels and mortality was observed. Individualized PEEP settings may be critical in minimizing the risk of PPCs and improving outcomes in major abdominal cancer surgeries.