Effects of Prone Positioning on Venous Return in Patients With Acute Respiratory Distress Syndrome*. Issue 5 (15th February 2021)

• Record Type: Journal Article
• Authors: Lai, Christopher; Adda, Imane; Teboul, Jean-Louis; Persichini, Romain; Gavelli, Francesco; Guérin, Laurent; Monnet, Xavier
• Is Part Of: Critical care medicine. Volume 49:Issue 5(2021)
• Page Start: 781
• Page End: 789
• Publication Date: 2021-02-15
• Subjects: fluid responsiveness -- heart-lung interactions -- intra-abdominal pressure -- mean systemic pressure -- venous return resistance; Critical care medicine -- Periodicals; Soins intensifs -- Périodiques; 616.028
• DOI: 10.1097/CCM.0000000000004849
• Languages: English
• ISSNs: 0090-3493

Abstract

Abstract : Supplemental Digital Content is available in the text. Abstract : OBJECTIVES: To examine the effects of prone positioning on venous return and its determinants such as mean systemic pressure and venous return resistance in patients with acute respiratory distress syndrome. DESIGN: Prospective monocentric study. SETTINGS: A 25-bed medical ICU. PATIENTS: About 22 patients with mild-to-severe acute respiratory distress syndrome in whom prone positioning was decided. INTERVENTIONS: We obtained cardiac index, mean systemic pressure, and venous return resistance (the latter two estimated through the heart-lung interactions method) before and during prone positioning. Preload responsiveness was assessed at baseline using an end-expiratory occlusion test. MEASUREMENTS AND MAIN RESULTS: Prone positioning significantly increased mean systemic pressure (from 24 mm Hg [19–34 mm Hg] to 35 mm Hg [32–46 mm Hg]). This was partly due to the trunk lowering performed before prone positioning. In seven patients, prone positioning increased cardiac index greater than or equal to 15%. All were preload responsive. In these patients, prone positioning increased mean systemic pressure by 82% (76–95%), central venous pressure by 33% (21–59%), (mean systemic pressure – central venous pressure) gradient by 144% (83–215)%, while it increased venous return resistance by 71% (60–154%). In 15 patients, prone positioning did not increase cardiac index greater than or equal to 15%. In these patients, prone positioning increased mean systemic pressure by 28% (18–56%) ( p < 0.05 vs. patients with significant increase in cardiac index), central venous pressure by 21% (7–54%), (mean systemic pressure – central venous pressure) gradient by 28% (23–86%), and venous return resistance by 37% (17–77%). Eleven of these 15 patients were preload unresponsive. CONCLUSIONS: Prone positioning increased mean systemic pressure in all patients. The resulting change in cardiac index depended on the extent of increase in (mean systemic pressure – central venous pressure) gradient, of preload responsiveness, and of the increase in venous return resistance. Cardiac index increased only in preload-responsive patients if the increase in venous return resistance was lower than the increase in the (mean systemic pressure –central venous pressure) gradient.