Related Experiment Video
Updated: Jun 18, 2026
Monitoring Lung Function with Electrical Impedance Tomography in the Intensive Care Unit
Published on: September 6, 2024
Impact of BMI on optimal PEEP titrated by electrical impedance tomography in ARDS patients: A retrospective study
Yutong Zhao1, Yi Chi2, Siyi Yuan2
1State Key Laboratory of Complex Severe and Rare Diseases, Department of Critical Care Medicine, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China; Department of Critical Care Medicine, First Hospital of Shanxi Medical University, Taiyuan, China.
Introduction:
Obese patients with acute respiratory distress syndrome (ARDS) may require higher positive end-expiratory pressure (PEEP), but the dose-response relationship between body mass index (BMI) and PEEP remained undetermined. This study aimed to investigate the relationship between BMI and the optimal PEEP titrated by electrical impedance tomography (EIT) in ARDS patients.
Methods:
ARDS patients who underwent EIT-guided PEEP titration were analyzed retrospectively. Patients were classified as obese (BMI ≥28 kg/m2) and non-obese (BMI <28 kg/m2). All patients received a decremental PEEP trial from 18 to 3 cmH2O, and the optimal PEEP was determined by the lowest sum of EIT-based regional overdistension and collapse.
Results:
Among 115 ARDS patients reviewed, average BMI was 25.1 (22.4-28.0) kg/m2, with 29 (25.2%) patients being obese and a mortality rate of 13.9%. Compared to non-obese patients, the titrated PEEP was higher in obese patients (12 [12-15] cmH2O vs 9 [6-12] cmH2O, p < 0.001). At the PEEP level of 18 cmH2O, overdistension was lower in the obese group (18.0 [14.0-26.6] % vs 25.4 [18.0-35.0] %, p = 0.023). A positive linear correlation was found between BMI and EIT-derived best PEEP (Spearman R = 0.46, p < 0.001). For detecting the optimal PEEP ≥12 cmH2O, a cutoff of BMI >30 kg/m2 would provide a specificity of 96.4% and a positive predictive value of 88.2%.
Conclusion:
A lower PEEP resulted in more collapse and a higher PEEP resulted in less overdistension in obese ARDS patients. The findings provided evidence to consider BMI in setting PEEP for this patient group.