Multimodal Analgesic Therapy With Gabapentin and Its Association With Postoperative Respiratory Depression

Isoflurane and postoperative respiratory depression following laparoscopic surgery: A retrospective propensity-matched analysis

Episodes of respiratory depression during the immediate postoperative recovery period (Phase I post-anesthesia recovery) have been associated with respiratory complications during Phase II recovery. Using multivariable analyses in several surgical cohorts, we previously identified potential associations between patient and perioperative factors and increased risk for Phase I respiratory depression. The aim of this study is to use the propensity-matched analysis to specifically assess for a potential association between the use of isoflurane and episodes of Phase I respiratory depression after laparoscopic operations. The electronic medical records of 8567 patients who underwent laparoscopic operations between January 1, 2010 and July 31, 2014, lasting ≥90 minutes, were retrospectively analyzed. Propensity-matched patients anesthetized without isoflurane were identified for 3403 patients anesthetized with isoflurane. Compared to the use of desflurane, sevoflurane or propofol infusion, maintenance of anesthesia with isoflurane was associated with an increased likelihood of Phase I respiratory depression (OR 95% CI, 1.32, 1.15-1.50, p < 0.001) and longer Phase I recovery (126 vs. 110 minutes, p < 0.001). The use of isoflurane was associated with increased rates of postoperative respiratory depression and postoperative recovery when compared to sevoflurane, desflurane, or propofol infusion.

Low minute ventilation episodes during anesthesia recovery following intraperitoneal surgery as detected by a non-invasive respiratory volume monitor

An electrical impedance-based noninvasive respiratory volume monitor (RVM) accurately reports minute volume, tidal volume and respiratory rate. Here we used the RVM to quantify the occurrence of and evaluate the ability of clinical factors to predict respiratory depression in the post-anesthesia care unit (PACU). RVM generated respiratory data were collected from spontaneously breathing patients following intraperitoneal surgeries under general anesthesia admitted to the PACU. Respiratory depression was defined as low minute ventilation episode (LMVe, < 40% predicted minute ventilation for at least 2 min). We evaluated for associations between clinical variables including minute ventilation prior to opioid administration and LMVe following the first PACU administration of opioid. Also assessed was a low respiratory rate (< 8 breaths per minute) as a proxy for LMVe. Of 107 patients, 38 (36%) had LMVe. Affected patients had greater intraoperative opioid dose, P = 0.05. PACU opioids were administered to 45 (42.1%) subjects, of which 27 (25.2%) had LMVe (P = 0.42) within 30 min following opioid. Pre-opioid minute ventilation < 70% of predicted normal value was associated with LMVe, P < 0.01, (sensitivity = 100%, specificity = 81%).Low respiratory rate was a poor predictor of LMVe (sensitivity = 11.8%). Other clinical variables (e.g., obstructive sleep apnea) were not found to be predictors of LMVe. Using RVM we identified that mild, clinically nondetectable, respiratory depression prior to opioid administration in the PACU was associated with the development of substantial subsequent respiratory depression during the PACU stay.