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Background: Monitored anesthesia care (MAC) and general anesthesia (GA) with endotracheal intubation are the 2 most used techniques for patients with acute ischemic stroke (AIS) undergoing endovascular thrombectomy. We aimed to test the hypothesis that increased arterial oxygen concentration during reperfusion period is a mechanism underlying the association between use of GA (versus MAC) and increased risk of in-hospital mortality., Methods: In this retrospective cohort study, data were collected at the Cleveland Clinic between 2013 and 2018. To assess the potential mediation effect of time-weighted average oxygen saturation (Spo2) in first postoperative 48 hours between the association between GA versus MAC and in-hospital mortality, we assessed the association between anesthesia type and post-operative Spo2 tertiles (exposure-mediator relationship) through a cumulative logistic regression model and assessed the association between Spo2 and in-hospital mortality (mediator-outcome relationship) using logistic regression models. Confounding factors were adjusted for using propensity score methods. Both significant exposure-mediator and significant mediator-outcome relationships are needed to suggest potential mediation effect., Results: Among 358 patients included in the study, 104 (29%) patients received GA and 254 (71%) received MAC, with respective hospital mortality rate of 19% and 5% (unadjusted P value <.001). GA patients were 1.6 (1.2, 2.1) (P < .001) times more likely to have a higher Spo2 tertile as compared to MAC patients. Patients with higher Spo2 tertile had 3.8 (2.1, 6.9) times higher odds of mortality than patients with middle Spo2 tertile, while patients in the lower Spo2 tertile did not have significant higher odds compared to the middle tertile odds ratio (OR) (1.8 [0.9, 3.4]; overall P < .001). The significant exposure-mediator and mediator-outcome relationships suggest that Spo2 may be a mediator of the relationship between anesthetic method and mortality. However, the estimated direct effect of GA versus MAC on mortality (ie, after adjusting for Spo2; OR [95% confidence interval {CI}] of 2.1 [0.9-4.9]) was close to the estimated association ignoring Spo2 (OR [95% CI] of 2.2 [1.0-5.1]), neither statistically significant, suggesting that Spo2 had at most a modest mediator role., Conclusions: GA was associated with a higher Spo2 compared to MAC among those treated by endovascular thrombectomy for AIS. Spo2 values that were higher than the middle tertile were associated with higher odds of mortality. However, GA was not significantly associated with higher odds of death. Spo2 at most constituted a modest mediator role in explaining the relationship between GA versus MAC and mortality., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2021 International Anesthesia Research Society.)

Background: Various multimodal analgesic approaches have been proposed for spine surgery. The authors evaluated the effect of using a combination of four nonopioid analgesics versus placebo on Quality of Recovery, postoperative opioid consumption, and pain scores., Methods: Adults having multilevel spine surgery who were at high risk for postoperative pain were double-blind randomized to placebos or the combination of single preoperative oral doses of acetaminophen 1,000 mg and gabapentin 600 mg, an infusion of ketamine 5 µg/kg/min throughout surgery, and an infusion of lidocaine 1.5 mg/kg/h intraoperatively and during the initial hour of recovery. Postoperative analgesia included acetaminophen, gabapentin, and opioids. The primary outcome was the Quality of Recovery 15-questionnaire (0 to 150 points, with 15% considered to be a clinically important difference) assessed on the third postoperative day. Secondary outcomes were opioid use in morphine equivalents (with 20% considered to be a clinically important change) and verbal-response pain scores (0 to 10, with a 1-point change considered important) over the initial postoperative 48 h., Results: The trial was stopped early for futility per a priori guidelines. The average duration ± SD of surgery was 5.4 ± 2.1 h. The mean ± SD Quality of Recovery score was 109 ± 25 in the pathway patients (n = 150) versus 109 ± 23 in the placebo group (n = 149); estimated difference in means was 0 (95% CI, -6 to 6, P = 0.920). Pain management within the initial 48 postoperative hours was not superior in analgesic pathway group: 48-h opioid consumption median (Q1, Q3) was 72 (48, 113) mg in the analgesic pathway group and 75 (50, 152) mg in the placebo group, with the difference in medians being -9 (97.5% CI, -23 to 5, P = 0.175) mg. Mean 48-h pain scores were 4.8 ± 1.8 in the analgesic pathway group versus 5.2 ± 1.9 in the placebo group, with the difference in means being -0.4 (97.5% CI; -0.8, 0.1, P = 0.094)., Conclusions: An analgesic pathway based on preoperative acetaminophen and gabapentin, combined with intraoperative infusions of lidocaine and ketamine, did not improve recovery in patients who had multilevel spine surgery.

Background: Perioperative treatment of type 2 diabetes with metformin, an oral hypoglycemic drug, is thought to increase the risk of life-threatening postoperative lactic acidosis. In contrast, metformin improves serum glucose control and has beneficial cardiovascular effects, which may decrease the risk of adverse outcomes. In this investigation we sought to determine the influence of metformin treatment on mortality and morbidity compared with treatment with other oral hypoglycemic drugs in diabetic patients undergoing cardiac surgery., Methods: In this retrospective investigation, 1284 diabetic patients, with recent oral hypoglycemic ingestion (presumed to be 8-24 h preoperatively), underwent cardiac surgery from 1994-2004. Propensity scores were calculated from a logistic model which included baseline characteristics and perioperative variables. Four-hundred-forty-three (85%) of the metformin-treated patients were matched on nearest propensity score using greedy matching techniques with 443 nonmetformin-treated patients. Postoperative outcomes were compared between matched metformin- and nonmetformin-treated patients., Results: In-hospital mortality, cardiac, renal, and neurologic morbidities were similar between groups. Metformin-treated patients had less postoperative prolonged tracheal intubation [OR (95% CI), 0.3 (0.1, 0.7), P = 0.003], infection [0.2 (0.1, 0.7), P = 0.007] and overall morbidities [0.4 (0.2, 0.8), P = 0.005]., Conclusions: These data suggest that recent metformin ingestion is not associated with increased risk of adverse outcome in cardiac surgical patients. Alternatively, metformin treatment may have beneficial effects.