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Training Level

Resident PGY 3


Henry Ford Hospital


Background: Current evidence suggests that a low tidal volume (TV) intraoperative ventilation strategy reduces the risk of postoperative pulmonary complications (PPCs). Morbidly obese patients have not only been underrepresented in these trials, but low-tidal volumes have not been formally tested in this population. The aim of this study was to explore the relationship between TV adjusted for ideal body weight (IBW) and the occurrence PPCs in morbidly obese patients undergoing abdominal surgery. Methods: Single-center retrospective study. We included patients with a BMI of at least 40 kg/m2, undergoing open or laparoscopic abdominal surgery lasting for at least 120 minutes. We obtained clinical variables to estimate the preoperative pulmonary risk, as well as intraoperative ventilator data to perform associations. PPCs were graded on severity and a composite score was developed. Outcomes were defined by ICD-10 diagnoses. All data was collected electronically using structured query language. Results: 859 patients were included in the analysis. Overall, patients were ventilated at a TV/IBW of 9.47 mL/Kg IBW and PPCs occurred in 8.3% of the sample. The occurrence of PPCs was correlated with the preoperative risk as defined by the ARISCAT score, where PPCs occurred in 6.3%, 9% and 30% for patients at low, intermediate and high risk, respectively. There is no association between TV/IBW and PPC score. This finding remained present after stratifying by ARISCAT categories (low, intermediate or high). In conclusion, tidal volume was not correlated to an increased frequency or severity of postoperative pulmonary complications in morbidly obese patients undergoing prolonged abdominal surgery. Future studies exploring ventilation strategies for the morbidly obese should pursue clinically relevant outcomes and optimal PEEP titration to support clinical practice recommendations.

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Lack of Association Between Tidal Volume and Postoperative Pulmonary Complications in Morbidly Obese Patients