Schulte, Phillip J.

BACKGROUND: We evaluated the hypothesis that the rate of postoperative decline in global cognition is greater in older adults exposed to general anesthesia with nitrous oxide (N 2 O) compared to general anesthesia without N 2 O. METHODS: Longitudinal measures of cognitive function were analyzed in nondemented adults, 70–91 years of age, enrolled in the Mayo Clinic Study of Aging. Linear mixed-effects models with time-varying covariates assessed the relationship between exposure to surgery with general anesthesia (surgery/GA) with or without N 2 O and the rate of long-term cognitive changes. Global cognition and domain-specific cognitive outcomes were defined using z scores, which measure how far an observation is, in standard deviations, from the unimpaired population mean. RESULTS: The analysis included 1819 participants: 280 exposed to GA without N 2 O following enrollment and before censoring during follow-up (median [interquartile range {IQR}] follow-up of 5.4 [3.9–7.9] years); 256 exposed to GA with N 2 O (follow-up 5.6 [4.0–7.9] years); and 1283 not exposed to surgery/GA (follow-up 4.1 [2.5–6.4] years). The slope of the global cognitive z score was significantly more negative following exposure to surgery/GA after enrollment (change in slope of −0.062 [95% confidence interval {CI}, −0.085 to −0.039] for GA without N 2 O, and −0.058 [95% CI, −0.080 to −0.035] for GA with N 2 O, both P < .001). The change in slope following exposure to surgery/GA did not differ between those exposed to anesthesia without versus with N 2 O (estimated difference −0.004 [95% CI, −0.035 to 0.026], P = .783). CONCLUSIONS: Exposure to surgery/GA is associated with a small, but statistically significant decline in cognitive z scores. Cognitive decline did not differ between anesthetics with and without N 2 O. This finding provides evidence that the use of N 2 O in older adults does not need to be avoided because of concerns related to decline in cognition.

AbstractIntroductionOur aim was to examine whether surgery with regional anesthesia (RA) is associated with accelerated long‐term cognitive decline comparable with that previously reported after general anesthesia (GA).MethodsLongitudinal cognitive function was analyzed in a cohort of 1819 older adults. Models assessed the rate of change in global and domain‐specific cognition over time in participants exposed to RA or GA.ResultsWhen compared with those unexposed to anesthesia, the postoperative rate of change of the cognitive global z‐score was greater in those exposed to both RA (difference in annual decline of −0.041, P = .011) and GA (−0.061, P < .001); these rates did not differ. In analysis of the domain‐specific scores, an accelerated decline in memory was observed after GA (−0.065, P < .001) but not RA (−0.011, P = .565).ConclusionsOlder adults undergoing surgery with RA experience decline of global cognition similar to those receiving GA; however, memory was not affected.

Objectives: Patients requiring admission to an ICU may subsequently experience cognitive decline. Our objective was to investigate longitudinal cognitive trajectories in older adults hospitalized in ICUs. We hypothesized that individuals hospitalized for critical illness develop greater cognitive decline compared with those who do not require ICU admission. Design: A retrospective cohort study using prospectively collected cognitive scores of participants enrolled in the Mayo Clinic Study of Aging and ICU admissions retrospectively ascertained from electronic medical records. A covariate-adjusted linear mixed effects model with random intercepts and slopes assessed the relationship between ICU admissions and the slope of global cognitive z scores and domains scores (memory, attention/executive, visuospatial, and language). Setting: ICU admissions and cognitive scores in the Mayo Clinic Study of Aging from October 1, 2004, to September 11, 2017. Patients: Nondemented participants age 50 through 91 at enrollment in the Mayo Clinic Study of Aging with an initial cognitive assessment and at least one follow-up visit. Interventions: None. Measurements and Main Results: Of 3,673 participants, 372 had at least one ICU admission with median (25–75th percentile) follow-up after first ICU admission of 2.5 years (1.2–4.4 yr). For global cognitive z score, admission to an ICU was associated with greater decline in scores over time compared with participants not requiring ICU admission (difference in annual slope = –0.028; 95% CI, –0.044 to –0.012; p < 0.001). ICU admission was associated with greater declines in memory (–0.029; 95% CI, –0.047 to –0.011; p = 0.002), attention/executive (–0.020; 95% CI, –0.037 to –0.004; p = 0.016), and visuospatial (–0.013; 95% CI, –0.026 to –0.001; p = 0.041) domains. ICU admissions with delirium were associated with greater declines in memory (interaction p = 0.006) and language (interaction p = 0.002) domains than ICU admissions without delirium. Conclusions: In older adults, ICU admission was associated with greater long-term cognitive decline compared with patients without ICU admission. These findings were more pronounced in those who develop delirium while in the ICU.

Telomere length (TL) is associated with cardiovascular disease (CVD) and cancer. Obstructive sleep apnea (OSA) is also linked to higher risk of CVD and cancer, and to TL. We investigated the association between TL and risk of major adverse cardiac events (MACE) and cancer in OSA patients. We studied 210 individuals undergoing sleep-related studies between 2000 and 2007. Baseline characteristics and follow-up data (available in 164 subjects) were obtained from clinic records. Incidence rates were calculated for the entire group and by OSA status. Hazard ratios were calculated to estimate effects of OSA and TL on risk of MACE and cancer. In total, 32 individuals (20%) developed MACE and/or cancer during 12.7-year follow-up. The OSA group had a higher likelihood of cancer (16.0 vs. 4.9 events per 1000 person-years, P = 0.044) but no clear evidence of an elevated incidence of MACE (10.8 vs. 4.8 events per 1000 person-years, P = 0.293) compared to the non-OSA group. There was no association between TL and MACE- (HR = 1.01, 95% CI 0.78–1.28), or cancer-risk (HR = 1.18, 95% CI 0.96–1.43). Our study warrants further investigation of any modulating effect of OSA on TL and the risk of MACE and cancer.

Background and objectives Buprenorphine is a partial µ-receptor agonist resistant to displacement from receptors by conventional opioids, which can block the effect of conventional opioids and may interfere with postoperative pain management. We aimed to quantify perioperative opioid use in patients receiving transdermal buprenorphine (TdBUP). Methods We identified patients receiving TdBUP who underwent surgery between 2004 and 2016. To compare opioid requirements (intravenous morphine equivalents (IV-MEq)), we constructed a matched study, matching each TdBUP patient with two opioid-naive patients by sex, age, and type of anesthesia and procedure. Results Nineteen unique patients underwent 22 procedures while receiving TdBUP. Total (IQR) amounts of IV-MEq (intraoperative, recovery room, and 24 hours after recovery-room discharge) were 98 (63, 145) and 46 (30, 65) mg IV-MEq for TdBUP and opioid-naive patients, respectively (p<0.001). Postoperative IV-MEq requirements were 54 (38, 90) and 15 (3, 35) mg for TdBUP and opioid-naive patients, respectively (p<0.001). Among TdBUP patients, higher preoperative doses of TdBUP were associated with greater postoperative opioid requirements (p=0.02). Specifically, patients with a 20 µg/hour TdBUP patch required 133.8 mg IV-MEq more postoperatively than patients with a 5 µg/hour patch (p=0.002). Following discharge from the recovery room, 17 (77%) TdBUP patients and 15 (34%) opioid-naive patients reported severe pain (OR 6.6 (95% CI 2.0 to 21.3); p<0.001; adjusting for baseline pain score, 5.0 (95% CI, 1.4 to 17.8); p=0.01). Conclusions Analgesic management for patients receiving TdBUP therapy must account for increased opioid needs, and greater preoperative doses of TdBUP were associated with greater postoperative opioid requirements.

Background and Purpose— Kidney dysfunction is common among patients hospitalized for ischemic stroke. Understanding the association of kidney disease with poststroke outcomes is important to properly adjust for case mix in outcome studies, payment models and risk-standardized hospital readmission rates. Methods— In this cohort study of fee-for-service Medicare patients admitted with ischemic stroke to 1579 Get With The Guidelines-Stroke participating hospitals between 2009 and 2014, adjusted multivariable Cox proportional hazards models were used to determine the independent associations of estimated glomerular filtration rate (eGFR) and dialysis status with 30-day and 1-year postdischarge mortality and rehospitalizations. Results— Of 204 652 patients discharged alive (median age [25th–75th percentile] 80 years [73.0–86.0], 57.6% women, 79.8% white), 48.8% had an eGFR ≥60, 26.5% an eGFR 45 to 59, 16.3% an eGFR 30 to 44, 5.1% an eGFR 15 to 29, 0.6% an eGFR <15 without dialysis, and 2.8% were receiving dialysis. Compared with eGFR ≥60, and after adjusting for relevant variables, eGFR <45 was associated with increased 30-day mortality with the risk highest among those with eGFR <15 without dialysis (hazard ratio [HR], 2.09; 95% CI, 1.66–2.63). An eGFR <60 was associated with increased 1-year poststroke mortality that was highest among patients on dialysis (HR, 2.65; 95% CI, 2.49–2.81). Dialysis was also associated with the highest 30-day and 1-year rehospitalization rates (HR, 2.10; 95% CI, 1.95–2.26 and HR, 2.55; 95% CI, 2.44–2.66, respectively) and 30-day and 1-year composite of mortality and rehospitalization (HR, 2.04; 95% CI, 1.90–2.18 and HR, 2.46; 95% CI, 2.36–2.56, respectively). Conclusions— Within the first year after index hospitalization for ischemic stroke, eGFR and dialysis status on admission are associated with poststroke mortality and hospital readmissions. Kidney function should be included in risk-stratification models for poststroke outcomes.

The lack of reliable, noninvasive methods to diagnose early nonalcoholic steatohepatitis (NASH) is a major unmet need. We aimed to determine the diagnostic accuracy of three‐dimensional magnetic resonance elastography (3D‐MRE), with shear stiffness measured at 60 Hz, damping ratio at 40 Hz, and magnetic resonance imaging proton density fat fraction (MRI‐PDFF) in the detection of NASH in individuals undergoing bariatric surgery. Obese adults at risk for NASH were enrolled between 2015 and 2017 (prospective cohort, n = 88) and 2010 and 2013 (retrospective cohort, n = 87). The imaging protocol consisted of multifrequency 3D‐MRE (mf3D‐MRE) with shear waves delivered at different frequencies to explore parameters that best correlated with histologic NASH, and MRI‐PDFF to estimate steatosis. The prospective cohort was used to establish the optimal mf3D‐MRE technical parameters for NASH detection. The two cohorts were then combined to derive predictive models of NASH and disease activity by nonalcoholic fatty liver disease activity score (NAS) using the three imaging parameters that correlated with NASH. A total of 175 patients (median age 45, 81% women, and 81 [46%] with histologic NASH) were used for model derivation. From the complex shear modulus output generated by mf3D‐MRE, the damping ratio at 40 Hz and shear stiffness at 60 Hz best correlated with NASH. The fat fraction obtained from MRI‐PDFF correlated with steatosis ( P < 0.05 for all). These three parameters were fit into a logistic regression model that predicted NASH with cross‐validated area under the receiver operating characteristic curve (AUROC) = 0.73, sensitivity = 0.67, specificity = 0.80, positive predictive value = 0.73 and negative predictive value = 0.74, and disease activity by NAS with cross‐validated AUROC = 0.82. Conclusion: The mf3D‐MRE allows identification of imaging parameters that predict early NASH and disease activity. This imaging biomarker represents a promising alternative to liver biopsy for NASH diagnosis and monitoring. The results provide motivation for further studies in nonbariatric cohorts.

BackgroundHeart rate and systolic blood pressure (SBP) are prognostic markers in heart failure (HF) with reduced ejection fraction (HFrEF). Their combination in rate pressure product (RPP) as well as their role in heart failure with preserved ejection fraction (HFpEF) remains unclear.HypothesisRPP and its components are associated with HFpEF outcomes.MethodsWe performed an analysis of Acute Study of Clinical Effectiveness of Nesiritide in Subjects With Decompensated Heart Failure (ASCEND‐HF; http://www.clinicaltrials.gov NCT00475852), which studied 7141 patients with acute HF. HFpEF was defined as left ventricular ejection fraction ≥40%. Outcomes were assessed by baseline heart rate, SBP, and RPP, as well as the change of these variables using adjusted Cox models.ResultsAfter multivariable adjustment, in‐hospital change but not baseline heart rate, SBP, and RPP were associated with 30‐day mortality/HF hospitalization (hazard ratio [HR]: 1.17 per 5‐bpm heart rate, HR: 1.20 per 10‐mm Hg SBP, and HR: 1.02 per 100 bpm × mm Hg RPP; all P < 0.05). Baseline SBP was associated with 180‐day mortality (HR: 0.88 per 10‐mm Hg, P = 0.028). Though change in RPP was associated with 30‐day mortality/HF hospitalization, the RPP baseline variable did not provide additional associative information with regard to outcomes when compared with assessment of baseline heart rate and SBP variables alone.ConclusionsAn increase in heart rate and SBP from baseline to discharge was associated with increased 30‐day mortality/HF hospitalization in HFpEF patients with acute exacerbation. These findings suggest value in monitoring the trend of vital signs during HFpEF hospitalization.

Observational data are often readily available or less costly to obtain than conducting a randomized controlled trial. With observational data, investigators may statistically evaluate the relationship between a treatment or therapy and outcomes. However, inherent in observational data is the potential for confounding arising from the nonrandom assignment of treatment. In this statistical grand rounds, we describe the use of propensity score methods (ie, using the probability of receiving treatment given covariates) to reduce bias due to measured confounders in anesthesia and perioperative medicine research. We provide a description of the theory and background appropriate for the anesthesia researcher and describe statistical assumptions that should be assessed in the course of a research study using the propensity score. We further describe 2 propensity score methods for evaluating the association of treatment or therapy with outcomes, propensity score matching and inverse probability of treatment weighting, and compare to covariate-adjusted regression analysis. We distinguish several estimators of treatment effect available with propensity score methods, including the average treatment effect, the average treatment effect for the treated, and average treatment effect for the controls or untreated, and compare to the conditional treatment effect in covariate-adjusted regression. We highlight the relative advantages of the various methods and estimators, describe analysis assumptions and how to critically evaluate them, and demonstrate methods in an analysis of thoracic epidural analgesia and new-onset atrial arrhythmias after pulmonary resection.

Abstract Background Few studies of how exposure of children to anesthesia may affect neurodevelopment employ comprehensive neuropsychological assessments. This study tested the hypothesis that exposure to multiple, but not single, procedures requiring anesthesia before age 3 yr is associated with adverse neurodevelopmental outcomes. Methods Unexposed, singly exposed, and multiply exposed children born in Olmsted County, Minnesota, from 1994 to 2007 were sampled using a propensity-guided approach and underwent neuropsychological testing at ages 8 to 12 or 15 to 20 yr. The primary outcome was the Full-Scale intelligence quotient standard score of the Wechsler Abbreviated Scale of Intelligence. Secondary outcomes included individual domains from a comprehensive neuropsychological assessment and parent reports. Results In total, 997 children completed testing (411, 380, and 206 unexposed, singly exposed, and multiply exposed, respectively). The primary outcome of intelligence quotient did not differ significantly according to exposure status; multiply exposed and singly exposed children scoring 1.3 points (95% CI, −3.8 to 1.2; P = 0.32) and 0.5 points (95% CI, −2.8 to 1.9; P = 0.70) lower than unexposed children, respectively. For secondary outcomes, processing speed and fine motor abilities were decreased in multiply but not singly exposed children; other domains did not differ. The parents of multiply exposed children reported increased problems related to executive function, behavior, and reading. Conclusions Anesthesia exposure before age 3 yr was not associated with deficits in the primary outcome of general intelligence. Although secondary outcomes must be interpreted cautiously, they suggest the hypothesis that multiple, but not single, exposures are associated with a pattern of changes in specific neuropsychological domains that is associated with behavioral and learning difficulties.