Evaluation of operating room reverse Trendelenburg positioning and its effect on postoperative hypoxemia, aspiration, and length of stay: a retrospective study of consecutive patients

C. Michael Dunham, Barbara M. Hileman, Amy E. Hutchinson, Tamara Antonaccio, Elisha A. Chance, Gregory S. Huang, Gregory Szmaj, Kristen Calabro, Cynthia Bishop, Tyson T. Schrickel

In 2014, this group published an investigation of surgical patients from 2012 who had substantial rates of postoperative hypoxemia (POH) and perioperative pulmonary aspiration (POPA). Therefore, we investigated whether intraoperative reverse Trendelenburg positioning (RTP) decreases POH and POPA rates. Consecutive ASA I-IV surgical patients who had preoperative pulmonary stability requiring general anesthesia with endotracheal intubation were evaluated. Using pulse oximetry, hypoxemia was documented intraoperatively and during the 48 h following PACU discharge. POPA was the presence of a pulmonary infiltrate with hypoxemia. In early 2015, a multifaceted effort was undertaken to enhance anesthesiologist and operating nurse awareness of RTP to potentially decrease POH and POPA rates. Analyses included (1) combining 2012 and 2015 cohorts to assess risk conditions, (2) comparing post-campaign 2015 (increased RTP) and 2012 cohorts, and (3) comparing 2015 patients with audit-documented RTP during surgery to the other 2015 patients. Combining the 500 patients in 2012 with the 1000 in 2015 showed that POH had increased mortality (2.3%), compared to no POH (0.2%; p = 0.0004). POH had increased postoperative length of stay (LOS) (4.6 days), compared to no POH (2.0 days; p < 0.0001). POPA had increased mortality (7.7%) and LOS (8.8 days), compared to no POPA (0.4%; p = 0.0004; 2.3 days; p < 0.0001). Open aortic, cranial, laparotomy, and neck procedures had greater POH (41.3%) and LOS (4.0 days), compared to other procedures (16.3%; p < 0.0001; 2.2 days; p < 0.0001). Glycopyrrolate on induction had lower POH (17.4%) and LOS (1.9 days), compared to no glycopyrrolate (21.6%; p = 0.0849; 2.7 days; p < 0.0001). POH was lower (18.1%) in 2015, than in 2012 (25.6%; p = 0.0007). POPA was lower with RTP in 2015 (0.6%), than in 2012 (4.8%; p = 0.0088). For the 2015 patients, LOS was lower with audit-documented RTP (2.2 days), compared to other patients (2.7 days; p = 0.0246). These findings are only hypothesis-generating. A randomized clinical trial is needed to confirm whether RTP has an inverse association with POH and POPA, and if RTP and glycopyrrolate are associated with improved outcomes. ClinicalTrials.gov, NCT02984657.