Mazzeffi, Michael A

Background. Patients having hip fracture surgery are at high risk for postoperative delirium. Red blood cell (RBC) transfusion may increase postoperative delirium risk by causing neuroinflammation. We hypothesized that RBC transfusion would be associated with postoperative delirium in patients having hip fracture surgery. Methods. An observational cohort study was performed using the United States National Surgical Quality Improvement Program (NSQIP) participant use files for hip fracture from 2016 to 2018. Propensity score analysis and inverse probability of treatment weighting (IPTW) were used to reduce bias from confounding. An IPTW adjusted odds ratio for developing postoperative delirium was calculated for patients who received RBC transfusion during surgery or in the 72 hours after. Results. There were 20,838 patients who had eligible current procedural terminology (CPT) codes for primary hip fracture surgery and complete study data. After employing strict exclusions to balance covariates and reduce bias, 3,715 patients remained in the IPTW cohort. Of these, 626 patients (16.9%) received RBC transfusion and 665 patients (17.9%) developed postoperative delirium. IPTW adjustment led to good covariate balance between patients who received RBC transfusion and those who did not. Patients who received RBC transfusion had significantly higher odds of postoperative delirium, IPTW adjusted odds ratio = 1.21, 95% CI = 1.03 to 1.43, andP = 0.02. Discharge location also differed significantly between patients who received RBC transfusion and those who did not (P < 0.001) with in-hospital mortality or referral to hospice occurring in 1.6% of patients who received RBC transfusion and 1.3% of patients who were not transfused. Conclusion. RBC transfusion is associated with increased odds of postoperative delirium after hip fracture surgery and may be associated with worse clinical outcome.

AbstractPurposeThe purpose of the study was to investigate factors associated with early discontinuation of low‐dose ketamine infusions due to adverse drug events (ADEs).MethodsA retrospective, matched case‐control study of surgical patients who received low‐dose ketamine infusions for postoperative pain over 6 years was conducted. Forty‐seven study patients, who required early discontinuation of their infusion due to ADEs, were included and matched 1:1 with 47 controls, who did not experience ADEs, for a total of 94 patients. The two groups were compared based on surgery type, American Society of Anesthesiologists (ASA) classification, administration of specific perioperative anxiolytic, anesthetic, and analgesic medications, and use of regional anesthesia.ResultsOf the study patients, 44.7% underwent spine procedures (vs. 34% of controls), 27.6% underwent abdominal procedures (vs. 8.5% of controls), 19.2% underwent orthopedic procedures (vs. 46.8% of controls), and 8.5% underwent thoracic procedures (vs. 6.4% of controls). There were no statistically significant differences in ASA classification, pre‐operative gabapentinoid and antidepressant use, average ketamine infusion dose, or postoperative use of peripheral nerve catheters, nonsteroidal anti‐inflammatory drugs (NSAIDs), acetaminophen, muscle relaxants, and nonbenzodiazepine sleep aides. Study patients had higher rates of intra‐operative volatile anesthetic use (78.7% vs. 57.7%, p = 0.03) and more postoperative opioid patient‐controlled analgesia (PCA) use (53.2% vs. 29.8%, p = 0.02) than controls. Control patients had higher rates of preoperative opioid use (76.7% vs. 53.2%, p = 0.02) and premedication with midazolam (89.4% vs. 70.2%, p = 0.02) than study patients.ConclusionPatients who required discontinuation of their low‐dose ketamine infusion due to ADEs were more likely to be opioid naïve, received less pre‐operative benzodiazepines, and had greater postoperative opioid PCA requirements. Control patients, on the other hand, had higher rates of pre‐operative opioid use and experienced fewer ADEs despite greater total ketamine doses.