Association between Use of Angiotensin-converting Enzyme Inhibitors or Angiotensin Receptor Blockers and Postoperative Delirium.

BACKGROUND: Angiotensin-converting enzyme inhibitors and angiotensin receptor blockers improve cognitive function. The authors therefore tested the primary hypothesis that preoperative use of angiotensin inhibitors is associated with less delirium in critical care patients. Post hoc, the association between postoperative use of angiotensin system inhibitors and delirium was assessed. METHODS: The authors conducted a single-site cohort study of adults admitted to Cleveland Clinic critical care units after noncardiac procedures between 2013 and 2018 who had at least one Confusion Assessment Method delirium assessment. Patients with preexisting dementia, Alzheimer's disease or other cognitive decline, and patients who had neurosurgical procedures were excluded. For the primary analysis, the confounder-adjusted association between preoperative angiotensin inhibitor use and the incidence of postoperative delirium was assessed. Post hoc, the confounder-adjusted association between postoperative angiotensin system inhibitor use and the incidence of delirium was assessed. RESULTS: The incidence of delirium was 39% (551 of 1,396) among patients who were treated preoperatively with angiotensin system inhibitors and 39% (1,344 of 3,468) in patients who were not. The adjusted odds ratio of experiencing delirium during critical care was 0.98 (95% CI, 0.86 to 1.10; P = 0.700) for preoperative use of angiotensin system inhibitors versus control. Delirium was observed in 23% (100 of 440) of patients who used angiotensin system inhibitors postoperatively before intensive care discharge, and in 41% (1,795 of 4,424) of patients who did not (unadjusted P < 0.001). The confounder-adjusted odds ratio for experiencing delirium in patients who used angiotensin system inhibitors postoperatively was 0.55 (95% CI, 0.43 to 0.72; P < 0.001). CONCLUSIONS: Preoperative use of angiotensin system inhibitors is not associated with reduced postoperative delirium. In contrast, treatment during intensive care was associated with lower odds of delirium. Randomized trials of postoperative angiotensin-converting enzymes inhibitors and angiotensin receptor blockers seem justified.

Association of Testosterone Replacement Therapy and the Incidence of a Composite of Postoperative In-Hospital Mortality and Cardiovascular Events in Men Undergoing Cardiac Surgery.

BACKGROUND: Data on testosterone replacement therapy and cardiovascular outcomes are conflicting, with the Food and Drug Administration requiring prescription testosterone preparations to indicate a possible increased cardiovascular risk. Whether patients on testosterone replacement therapy undergoing cardiac surgery have an increased risk of postoperative in-hospital mortality and cardiovascular events remains unknown. We therefore sought to identify the impact of testosterone replacement on the incidence of a composite of postoperative in-hospital mortality and cardiovascular events in men undergoing cardiac surgery. METHODS: After institutional review board approval, data from male American Society of Anesthesiologists III/IV patients ≥40 years of age who underwent cardiac surgery between May 2005 and March 2017 at the Cleveland Clinic (Cleveland, OH) main campus were included. The primary exposure was preoperative testosterone use. The primary outcome was a collapsed composite of postoperative in-hospital mortality and cardiovascular events, including myocardial infarction, stroke, and pulmonary embolism. The secondary outcome was a collapsed composite of minor cardiovascular events, including postoperative rhythm disturbance requiring permanent device, atrial fibrillation, and deep venous thrombosis. We compared patients who received testosterone and those who did not, using propensity score matching within surgical procedure matches. Moreover, as a sensitivity analysis, we used a multivariable logistic regression model to assess the association between testosterone replacement therapy and major or minor cardiovascular events adjusted for potential baseline and intraoperative confounders by including all eligible patients. RESULTS: Among 20,604 patients who met inclusion and exclusion criteria, 301 patients who used testosterone routinely within 1 month before the surgery were matched to 1505 of 20,303 patients who did not use testosterone. Among the matched cohort, 8 (2.7%) patients in the testosterone group and 45 (3.0%) in the nontestosterone group had ≥1 major cardiovascular adverse event after surgery. The adjusted odds ratio was 0.89 (95% CI, 0.41-1.90; P = .756), comparing testosterone to nontestosterone patients. As for the secondary outcomes, 89 (30%) patients in the testosterone group and 525 (35%) patients in the nontestosterone group had ≥1 minor cardiovascular event. The odds of minor events were not significantly different, with an odds ratio of 0.78 (95% CI, 0.60-1.02; P = .074) comparing testosterone to nontestosterone patients. CONCLUSIONS: Preoperative testosterone is not associated with a statistically significant increased incidence of a composite of postoperative in-hospital mortality and cardiovascular events after cardiac surgery.

Association of Intraoperative Tidal Volumes and Acute Kidney Injury After Noncardiac Surgery.

BACKGROUND: Patients with acute lung injury who received lower tidal volume (VT) ventilation had significantly fewer days with acute kidney injury (AKI) when compared to those receiving higher VTs. There is a paucity of studies on the relationship between intraoperative VTs and postoperative AKI in patients undergoing noncardiac surgery. We therefore sought to assess the association of mean delivered intraoperative VT per kilogram based on predicted body weight (PBW) and postoperative AKI. METHODS: This retrospective cohort study was conducted in a large tertiary multispecialty academic medical center. Adult patients who underwent noncardiac surgery between January 2005 and July 2016 under general anesthesia with endotracheal intubation and mechanical ventilation were included. A total of 41,224 patients were included in the study.The relationship between mean intraoperative VT per PBW and AKI was assessed using logistic regression, adjusting for prespecified potential confounding variables. The secondary outcomes were postoperative major pulmonary complications, myocardial injury after noncardiac surgery (MINS), and in-hospital mortality. RESULTS: The incidence of AKI was 10.9% in the study population. Postoperative renal replacement therapy was required in 0.1% of patients. Higher delivered mean intraoperative VT per PBW was significantly associated with increased odds of AKI. The estimated odds ratio for each 1 mL increase in VT per kilogram of PBW (1 unit) was 1.05 (95% confidence interval [CI], 1.02-1.08; P = .001), after adjusting for potential confounding variables. A higher delivered mean intraoperative VT per PBW was significantly associated with increased odds of postoperative myocardial injury and was not significantly associated with major postoperative pulmonary complications or in-hospital mortality after noncardiac surgery. CONCLUSIONS: In adult patients undergoing noncardiac surgery, higher delivered mean intraoperative VTs per PBW are associated with an increased odds of developing AKI.

Association of Body Mass Index and Postoperative Acute Kidney Injury in Patients Undergoing Laparoscopic Surgery.

BACKGROUND: Whether the deleterious effects of carbon dioxide pneumoperitoneum on the kidneys are exacerbated in the obese population remains unknown. We hypothesized that increased body mass index (BMI) is associated with an increased incidence of postoperative acute kidney injury (AKI) in patients undergoing noncardiac laparoscopic surgery. METHODS: Following institutional review board approval, we analyzed data on 8,543 adult patients with American Society of Anesthesiologists physical status scores of I-IV who had inpatient noncardiac laparoscopic surgery from 2005-2014. Because the exposure (current BMI) is a chronic condition, we a priori assumed that diabetes mellitus, hypertension, coronary artery disease, and chronic obstructive pulmonary disease might mediate the effect of obesity on outcome. Our primary analysis was a proportional odds logistic regression model with current BMI as a predictor and AKI as an ordinal outcome. RESULTS: After controlling for potential confounding variables, the odds of developing a more serious level of AKI was 7% (95% CI 0%, 15%) greater with a 5-unit increase in BMI (P=0.05). When the analysis was adjusted for the a priori mediators in an attempt to estimate the pure effect of BMI on AKI, the result was no longer significant (Wald test P=0.35), with the residual effect of BMI of 3% (95% CI -4%, 11%). CONCLUSION: We found a marginal association between BMI and an increased risk of developing AKI in adult patients after having noncardiac laparoscopic surgery. The BMI effect became insignificant when potential mediator variables were considered. The association of BMI and AKI after noncardiac laparoscopic surgery is likely mediated through components of the metabolic syndrome.

Association of Testosterone Replacement Therapy and the Incidence of a Composite of Postoperative In-hospital Mortality and Cardiovascular Events in Men Undergoing Noncardiac Surgery.

BACKGROUND: Whether patients on testosterone replacement therapy undergoing noncardiac surgery have an increased risk of postoperative in-hospital mortality and cardiovascular events remains unknown. We therefore sought to identify the impact of testosterone replacement on the incidence of a composite of postoperative in-hospital mortality and cardiovascular events in men undergoing noncardiac surgery. METHODS: Data from male American Society of Anesthesiologists I through IV patients 40 yr or older who underwent noncardiac surgery between May 2005 and December 2015 at the Cleveland Clinic (Cleveland, Ohio) main campus were included. The primary exposure was preoperative testosterone use. The primary outcome was a composite of postoperative in-hospital mortality and cardiovascular events. We compared patients who received testosterone and those who did not using propensity score matching within surgical procedure matches. RESULTS: Among 49,273 patients who met inclusion and exclusion criteria, 947 patients on testosterone were matched to 4,598 nontestosterone patients. The incidence of in-hospital mortality was 1.3% in the testosterone group and 1.1% in the nontestosterone group, giving an odds ratio of 1.17 (99% CI, 0.51 to 2.68; P = 0.63). The incidence of myocardial infarction was 0.2% in the testosterone group and 0.6% in the nontestosterone group (odds ratio = 0.34; 99% CI, 0.05 to 2.28; P = 0.15). Similarly, no significant difference was found in stroke (testosterone vs. nontestosterone: 2.0% vs. 2.1%), pulmonary embolism (0.5% vs. 0.7%), or deep venous thrombosis (2.0% vs. 1.7%). CONCLUSIONS: Preoperative testosterone is not associated with an increased incidence of a composite of postoperative in-hospital mortality and cardiovascular events.

The association of preoperative statin use and acute kidney injury after noncardiac surgery.

BACKGROUND: Our objective was to examine the association between preoperative statin therapy and the incidence of postoperative acute kidney injury (AKI) in patients undergoing elective noncardiac surgery. METHODS: We analyzed the electronic records of 57,246 patients who had elective noncardiac surgery at the Cleveland Clinic Main Campus between December 2004 and March 2010. Patients were divided into 2 groups depending on preoperative therapy with statin drugs. Our primary outcome was AKI, defined as "risk," "injury," or "failure" using the RIFLE (Risk, Injury, Failure, Loss, and End-stage Kidney) criteria. Secondary outcomes included postoperative dialysis and all-cause hospital mortality. Each statin user was matched to a nonuser based on propensity scores. The propensity scores were estimated using a multivariable logistic regression model, incorporating all available baseline potential confounders. After the propensity-matching procedure, we performed final analyses for the primary and secondary outcomes. For the primary analysis, we used a univariable logistic regression model to estimate the odds ratio (OR) (and 95% confidence intervals) for AKI, postoperative dialysis, and hospital mortality between matched statin users and nonusers. RESULTS: Of the total group, 23,745 records were unusable because of missing data. Among the remaining 28,508 patients analyzed, the overall incidence of AKI was 6.1%. Three hundred sixty-one of 4805 statin users (7.5%) and 1377 of 23,703 nonusers (5.8%) experienced AKI. The incidence of postoperative dialysis was 0.05%. Six statin users (0.12%) and 8 nonusers (0.03%) required dialysis postoperatively. The incidence of hospital mortality was 0.62%. Mortality was observed for 47 patients (1.0%) and 130 patients (0.5%), respectively. Among 4172 matched pairs, the incidence (95% confidence interval) of AKI was 7.1% (6.2%, 8.1%) in the matched statin users and 8.0% (7.1%, 9.0%) in the nonusers, corresponding to an OR of 0.88 (0.75, 1.03), which was not statistically significant (P = 0.12, χ(2) test). The secondary outcomes were also not significantly different in matched statin users and nonusers. Postoperative dialysis was required for 0.10% (0.02%, 0.33%) and 0.12% (0.04%, 0.37%) of patients in the respective groups (OR = 0.80 [0.16, 3.70]; P = 0.74). Hospital mortality occurred in 1.0% (0.7%, 1.5%) and 1.3% (0.9%, 1.8%) of patients, respectively (OR = 0.76 [0.47, 1.20]; P = 0.18). CONCLUSIONS: Our data did not support the hypothesis that preoperative statin therapy in doses routinely used to treat hypercholesterolemia is associated with a change in the incidence of AKI, postoperative dialysis, or hospital mortality in patients undergoing noncardiac surgery.

Colloid update.

This update aims to provide an evidence based review of natural and synthetic colloids with a special emphasis on the various generations of the synthetic colloid hydroxyethyl starch. The effect of 1(st), 2(nd) and 3(rd) generation hetastarches on bleeding, coagulopathy, acute kidney injury and mortality will be discussed. The results of randomised controlled trials addressing morbidity and mortality outcomes of colloid versus crystalloid resuscitation in critically ill patients will be described. In addition, the rationale and evidence behind early goal directed fluid therapy (EGDFT) including a practical approach to assessment of dynamic measures of fluid responsiveness will be presented.

Association of red blood cell transfusion and postoperative outcomes after endovascular aortic repair.

BACKGROUND: Several studies have documented worse postoperative outcomes in patients who received red blood cell (RBC) transfusion perioperatively during cardiac surgery or in critical care settings. These findings were attributed to activation of the inflammatory response with the release of cytokines and immune suppression. The aim of this study was to evaluate the association of RBC transfusion on the day of surgery and postoperative outcomes following endovascular aortic repair (EVAR). METHODS: A total of 510 patients who underwent EVAR from April 2005 to March 2007 were considered for analysis. The exposure of interest was whether or not patients receive RBC transfusion on the day of surgery. The primary outcome was a composite in-hospital morbidity/mortality outcome. The authors assessed the association between RBC transfusion and our composite outcome using logistic regression after adjusting for the available potential confounders using propensity score matching. RESULTS: Propensity scores were estimated for 418 out of the 510 patients; 92 patients were not included because of missing data. Propensity matching resulted in 42 successfully matched pairs. Median (quartiles) propensity score was 0.46 (0.28, 0.66) for the matched patients with transfusion and 0.46 (0.29, 0.61) for the matched patients without transfusion (P = .75, Wilcoxon rank sum test). Results of the multivariable model developed after propensity score matching suggest that RBC transfusion was not significantly associated with experiencing a postoperative complication; estimated odds ratio (95% confidence interval) of 2.7 (0.8, 9.0), P = .11. CONCLUSION: In this study, RBC transfusion was not independently associated with an increased incidence of in-hospital morbidity and mortality after EVAR.