Faculty Bibliography

BACKGROUND:Myocardial injury after non-cardiac surgery (MINS) is a common post-operative cardiovascular complication and is associated with short and long-term mortality. The objective of this study was to describe the contemporary management of patients with and without MINS after total joint and spine orthopedic surgery at a large urban health system in the United States. METHODS:Adults admitted for total joint and major spine surgery from January 2013 through December 2015 with ≥1 cardiac troponin (cTn) measurement during their hospitalization were identified. MINS was defined by a peak cTn above the 99th percentile of the upper reference limit. Demographics, medical comorbidities, and admission and discharge medications were reviewed for all patients. RESULTS:A total of 2561 patients underwent 2798 orthopedic surgeries, and 236 cases of MINS were identified. Patients with MINS were older (71.9 ± 10.9 vs. 67.0 ± 10.0, p < 0.001) and more likely to have cardiovascular risk factors, including hypertension, chronic kidney disease, prior stroke, coronary artery disease, prior MI, and a history of heart failure. Among patients with MINS, only 112 (47.5%) were discharged on a combination of aspirin and statin. Patients with MINS were more likely to be prescribed a statin (154 [65.3%] vs. 1463 [57.1%], p = 0.018), beta-blocker (147 [62.3%] vs. 1194 [46.6%], p < 0.001), and oral anticoagulation (65 [27.5%] vs. 436 [17.0%], p < 0.001) than patients without MINS. CONCLUSIONS:The proportion of patients with MINS who were prescribed medical therapy for atherosclerotic cardiovascular disease was low. Additional efforts to determine optimal management of MINS are warranted.

BACKGROUND:Patients on antidepressant or antianxiety medications often have complex perioperative courses due to difficult pain management, altered coping mechanisms, or medication-related issues. This study examined the relationship between preoperative antidepressants and antianxiety medications on postoperative hospital length of stay while controlling for confounding variables. METHODS:From an administrative database of 48,435 adult patients who underwent noncardiac surgery from 2011 to 2014 at a single, large urban academic institution, multivariable zero-truncated negative binomial regression analyses controlling for age, sex, medical comorbidities, and surgical type were performed to assess whether preoperative exposure to antidepressant or antianxiety medication use was associated with postoperative hospital length of stay. RESULTS:There were 5111 (10.5%) patients on antidepressants and 4912 (10.1%) patients on antianxiety medications. The median length of stay was 3 days (interquartile range = 2-6). After controlling for confounding variables, preoperative antidepressant medication was associated with increased length of stay with an incidence rate ratio of 1.04 (99% confidence interval, 1.0-1.08, P < .001) and antianxiety medication with an incidence rate ratio of 1.1 (99% confidence interval, 1.06-1.14; P < .001). CONCLUSIONS:The association between antidepressants or antianxiety medications and increased postoperative length of stay suggests that these patients may require greater attention in the perioperative period to hasten recovery, which may involve integrating preoperative counseling, postoperative psychiatric consults, or holistic recovery approaches into enhanced recovery protocols.

WHAT WE ALREADY KNOW ABOUT THIS TOPIC/UNASSIGNED:WHAT THIS ARTICLE TELLS US THAT IS NEW: BACKGROUND:: Hypotension is a risk factor for adverse perioperative outcomes. Machine learning methods allow large amounts of data for development of robust predictive analytics. The authors hypothesized that machine learning methods can provide prediction for the risk of postinduction hypotension METHODS:: Data was extracted from the electronic health record of a single quaternary care center from November 2015 to May 2016 for patients over age 12 that underwent general anesthesia, without procedure exclusions. Multiple supervised machine learning classification techniques were attempted, with postinduction hypotension (mean arterial pressure less than 55 mmHg within 10 min of induction by any measurement) as primary outcome, and preoperative medications, medical comorbidities, induction medications, and intraoperative vital signs as features. Discrimination was assessed using cross-validated area under the receiver operating characteristic curve. The best performing model was tuned and final performance assessed using split-set validation. RESULTS:Out of 13,323 cases, 1,185 (8.9%) experienced postinduction hypotension. Area under the receiver operating characteristic curve using logistic regression was 0.71 (95% CI, 0.70 to 0.72), support vector machines was 0.63 (95% CI, 0.58 to 0.60), naive Bayes was 0.69 (95% CI, 0.67 to 0.69), k-nearest neighbor was 0.64 (95% CI, 0.63 to 0.65), linear discriminant analysis was 0.72 (95% CI, 0.71 to 0.73), random forest was 0.74 (95% CI, 0.73 to 0.75), neural nets 0.71 (95% CI, 0.69 to 0.71), and gradient boosting machine 0.76 (95% CI, 0.75 to 0.77). Test set area for the gradient boosting machine was 0.74 (95% CI, 0.72 to 0.77). CONCLUSIONS:The success of this technique in predicting postinduction hypotension demonstrates feasibility of machine learning models for predictive analytics in the field of anesthesiology, with performance dependent on model selection and appropriate tuning.

Backround: Intracranial surgery is high risk for postoperative nausea and vomiting. Despite routine prophylaxis with conventional antiemetics, about 50% of patients having this type of surgery will experience PONV. This is distressing and uncomfortable for patients, but it also runs the risk of precipitating intracranial bleeding. Recent retrospective reviews and randomized, placebo controlled trials have found that preoperative midazolam is associated with a decreased incidence of PONV. The mechanism for this effect is uncertain. If this intervention is effective it could become part of a multimodal approach for preventing PONV in patients having craniotomies. Currently intravenous midazolam 2 mg is used with other medications for induction of general anesthesia. Some craniotomy patients receive it and others do not, based on anesthesia provider preference and patient anxiety level. Comparing patients who received midazolam with those that did not could offer insight into the effectiveness of this treatment. Methods: Our group conducted a retrospective chart review of patients receiving craniotomies over a 1-year period. There were 463 craniotomies over the time range (June 1, 2016 to May 31, 2017). Indications for craniotomy included tumors, arteriovenous malformations, aneurysms and seizures. Patients were separated into 2 groups; those that received midazolam 2mg at induction and those that did not receive midazolam. Demographic data and other medications administered were extracted from the anesthesia record. Administration of rescue antiemetics for the first 24 hours, was used to indicate the presence of postoperative nausea and vomiting. A statistical analysis was performed. Results: Administration of IV midazolam 2mg was not associated with reduced PONV (odds ratio [OR] = 1.2; 95% confidence interval [CI], 0.1-2.7; P = 0.43) within 24 hours. Variables accounted for included age, sex, BMI, smoking status, history of PONV, and other anesthetic drugs administered. Conclusions: Administration of midazolam 2mg intravenously at induction was not effective in reducing overall PONV in craniotomy patients. It is possible the midazolam dose was too small, or the operation was too long for midazolam at induction to make a statistical difference. Of note, the overall incidence of PONV was 31% which is considerably lower than expected after this surgery. This may be due to the high percentage of patients who received a propofol based anesthetic along with dexamethasone and ondansetron. The low overall incidence of PONV may have diminished the chance of detecting the antiemetic effect of midazolam. (Table Presented)

PURPOSE/OBJECTIVE:Obstructive sleep apnea (OSA) is a risk factor for complications with postoperative opioid use, and in those patients with known or suspected OSA, minimization of postoperative opioids is recommended. We hypothesize that despite these recommendations, surgical patients with known or suspected OSA are prescribed postoperative opioids at hospital discharge at similar doses to those without OSA. METHODS:This was a retrospective analysis of the electronic health records of surgical patients from 1 November 2016 to 30 April 2017 at a single academic institution. Patients with a known diagnosis of OSA or a STOP-Bang score ≥ 5 were compared with those without OSA for the amount of postoperative discharge opioid medication using multivariable linear regression. RESULTS:Of the 17,671 patients analyzed, 1,692 (9.6%) had known or suspected OSA with 1,450 (86%) of these patients discharged on opioid medications. Of the 15,979 patients without OSA, 12,273 (77%) were discharged on opioid medications. The total median [interquartile range (IQR)] oral morphine equivalents (OME) for all patients was 150 [0-338] mg and for patients with known or suspected OSA was 160 [0-450] mg, an unadjusted comparison showing an 18% difference in OME (95% confidence interval [CI], 3% to 35%; P = 0.02). The analysis, after adjusting for confounders, showed no significant difference in the amount of opioids prescribed to OSA or non-OSA patients (8% difference in total OME; 95% CI, -6% to 25%; P = 0.26). CONCLUSION/CONCLUSIONS:This study shows that surgical patients at risk for OSA or confirmed OSA are prescribed opioids at similar rates and doses upon discharge despite guidelines that recommend minimizing opioid use in OSA patients. These findings indicate a need to implement different strategies to reduce the prescription of opioids to patients with OSA.