Differential Effects of Intraoperative Positive End-expiratory Pressure (PEEP) on Respiratory Outcome in Major Abdominal Surgery Versus Craniotomy

Abstract

Objectives In this study, we examined whether (1) positive end-expiratory pressure (PEEP) has a protective effect on the risk of major postoperative respiratory complications in a cohort of patients undergoing major abdominal surgeries and craniotomies, and (2) the effect of PEEP is differed by surgery type. Background Protective mechanical ventilation with lower tidal volumes and PEEP reduces compounded postoperative complications after abdominal surgery. However, data regarding the use of intraoperative PEEP is conflicting. Methods In this observational study, we included 5915 major abdominal surgery patients and 5063 craniotomy patients. Analysis was performed using multivariable logistic regression. The primary outcome was a composite of major postoperative respiratory complications (respiratory failure, reintubation, pulmonary edema, and pneumonia) within 3 days of surgery. Results Within the entire study population (major abdominal surgeries and craniotomies), we found an association between application of PEEP ≥5cmH2O and a decreased risk of postoperative respiratory complications compared with PEEP <5cmH2O. Application of PEEP >5cmH2O was associated with a significant lower odds of respiratory complications in patients undergoing major abdominal surgery (odds ratio 0.53, 95% confidence interval 0.39 – 0.72), effects that translated to deceased hospital length of stay [median hospital length of stay : 6 days (4–9 days), incidence rate ratios for each additional day: 0.91 (0.84 - 0.98)], whereas PEEP >5cmH2O was not significantly associated with reduced odds of respiratory complications or hospital length of stay in patients undergoing craniotomy. Conclusions The protective effects of PEEP are procedure specific with meaningful effects observed in patients undergoing major abdominal surgery. Our data suggest that default mechanical ventilator settings should include PEEP of 5–10cmH2O during major abdominal surgery.

Migraine and risk of perioperative ischemic stroke and hospital readmission: hospital based registry study

“…We used patient data from all sources to form one de-identified database, as previously reported by our group. [23][24][25] Patient involvement No patients were involved in setting the research question or the outcome measures, nor were they involved in developing plans for recruitment, design, or implementation of the study. No patients were asked advice on interpretation or writing up of results.…”

Perioperative lung protective ventilation

“…Two small RCTs have found that 10 cm H 2 O PEEP may confer additional physiologic benefit 6061. With regard to PPCs, a large retrospective study of more than 11 000 abdominal and intracranial operations showed an association between the use of at least 5 cm H 2 O PEEP and a significantly decreased odds of PPCs compared with less than 5 cm H 2 O PEEP (odds ratio 0.72, 0.61 to 0.85) 62. Of note, secondary analysis did not show a benefit for craniotomy patients, suggesting that PEEP’s protective effect may not extend to patients at lower risk for atelectasis.…”

Mechanical ventilation mode and postoperative pulmonary complications

“…Our study was conducted in the operating theatre setting and not in an intensive care unit where patients' lungs are more likely to be difficult to ventilate due to reduced compliance. Since controlling for compliance did not influence our outcomes, we believe that our findings are valid across the spectrum of compliance studied [3].…”

“…Existing data suggest the presence of wide variability in peri-operative ventilation practices that are not driven by patient comorbidities or procedural characteristics [4]. We conclude, based on our own data, that in a majority of patients, volume-controlled ventilation with low driving pressure and optimal, procedure-specific PEEP [3,4]…”

“…Are the authors confident about their findings, despite the potential confounding influence of these? I would argue that it is not the mode of mechanical ventilation that is important [3], but rather intraoperative vigilance of the driving pressures, particularly when respiratory compliance changes frequently, and use of appropriate ventilator alarms and pressure limits. Considering the long-term detrimental consequences of PPCs [4], would the authors agree there is now sufficient equipoise for a randomised controlled trial to determine if any single mode of mechanical ventilation is superior to the others in preventing PPCs?…”