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

BACKGROUND: 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. METHODS: 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. RESULTS: 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). CONCLUSIONS: 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. TRIAL REGISTRATION: ClinicalTrials.gov, NCT02984657.

Gene expression in slipped capital femoral epiphysis. Evaluation with laser capture microdissection and quantitative reverse transcription-polymerase chain reaction.

BACKGROUND: Slipped capital femoral epiphysis is a poorly understood condition affecting adolescents. Prior studies have suggested that the etiology may be related to abnormal collagen in the growth plate cartilage, but we are not aware of any investigations analyzing collagen or other structural proteins on a molecular level in the affected tissue. This study was performed to evaluate expression of mRNA for key structural molecules in growth plate chondrocytes of patients with slipped capital femoral epiphysis. METHODS: A core biopsy of the proximal femoral physis was performed in nine patients with slipped capital femoral epiphysis, and the specimens were compared with five specimens from the normal distal femoral and proximal tibial and fibular physes of age-matched patients treated surgically for a limb-length inequality. We utilized laser capture microdissection techniques followed by quantitative reverse transcription-polymerase chain reaction analysis to determine if a change or abnormality in type-II-collagen and/or aggrecan gene expression may be associated with slipped capital femoral epiphysis. With these techniques, we correlated chondrocyte spatial location and gene expression to provide greater insight into this pathological condition and a more complete understanding of growth plate biology in general. RESULTS: Downregulation of both type-II collagen and aggrecan was found in the growth plates of the subjects with slipped capital femoral epiphysis when compared with the levels in the age-matched controls. In eight specimens from affected patients, the level of expression of type-II-collagen mRNA was, on the average (and standard error of the mean), 13.7% +/- 0.2% of that in four control specimens and the aggrecan level averaged only 26% +/- 0.2% of the control aggrecan level. CONCLUSIONS: The decreases that we identified in type-II-collagen and aggrecan expression would affect the quantity, distribution, and organization of both components in a growth plate, but these changes could be associated with either the cause or the result of a slipped capital femoral epiphysis.