Postoperative delirium following transcatheter aortic valve implantation: a historical cohort study.

PURPOSE: Transcatheter aortic valve implantation (TAVI) techniques show favourable survival outcomes in high-risk patients, but the incidence of postoperative delirium is unknown. We conducted a historical cohort study to compare postoperative delirium in retrograde transfemoral (TF) versus anterograde transapical (TA) TAVI procedures. We also sought to identify independent predictors of delirium following TAVI. METHODS: We performed a retrospective chart review on all patients who underwent TF (n = 77) or TA (n = 45) TAVI during 2008 and 2009 at St. Paul's Hospital (Vancouver, BC, Canada), the pioneering centre for these procedures. The primary outcome was a documented physician diagnosis of delirium. Abstracted data included information on demographics, medical history, surgical procedure, anesthesia, and postoperative care. We employed a multivariable logistic regression to identify independent predictors of delirium. RESULTS: Delirium occurred in 12% of TF patients vs 53% of TA patients (P < 0.001). Preoperatively, the groups differed significantly in the rates of hypertension, pulmonary hypertension, dyslipidemia, peripheral vascular disease, congestive heart failure, previous myocardial infarction, and memory impairment. Differences in anesthetic management were also observed between the TF vs TA groups regarding inhalational anesthetics, opioids, neuromuscular blockers, antihemorrhagic drugs, and antibiotics. Independent predictors for delirium after TAVI included coronary artery disease (odds ratio [OR] 12.7; 95% confidence interval [CI] 1.0 to 154.9), cognitive impairment (OR 6.5; 95% CI 1.8 to 23.2), and cardiac arrhythmia (OR 3.5; 95% CI 1.1 to 11.6). Compared to the TF approach, TA-TAVI independently increased the risk of delirium (OR 13.8; 95% CI 3.3 to 59.0). CONCLUSIONS: Patients undergoing TA-TAVI had a markedly increased incidence of postoperative delirium compared with patients undergoing TF-TAVI.

Incidence of and Risk Factors for Delirium After Cardiac Surgery at a Quaternary Care Center: A Retrospective Cohort Study.

OBJECTIVE: Delirium after cardiac surgery is associated with persistent cognitive deficits and increased mortality. The authors' objective was to determine the incidence of and risk factors for delirium in a mixed cohort of patients undergoing on-pump and off-pump cardiac surgery and transcatheter aortic valve implantations (TAVI) in a Canadian quaternary care center. This study followed a pilot from the same center on patients treated in 2007. DESIGN: A retrospective cohort study. SETTING: A quaternary care center in Vancouver, B.C., Canada. PARTICIPANTS: Patients undergoing cardiopulmonary bypass grafts (CABG), conventional valve replacements, combined CABG-valve replacements, transfemoral TAVI, or transapical TAVI in 2008. INTERVENTIONS: Data from 679 charts on demographics, medical history, medications, laboratory results, surgical procedure, and anesthesia were abstracted and analyzed using univariate and multivariate analyses. Nurses screened for delirium using the Confusion Assessment Method, and the final diagnoses were made clinically by physicians. Risk factors were identified using logistic regression and bootstrapping. MEASUREMENTS AND MAIN RESULTS: Delirium occurred in 28% of patients. Delirium was most common in transapical TAVI (47%), and least common in transfemoral TAVI (17%). Delirious patients were older and had greater preoperative cardiac and neurologic burdens than nondelirious patients. Age≥64 years, history of delirium, history of stroke/transient ischemic attack, cognitive impairment, depression, and preoperative use of beta-blocker(s) were associated independently with delirium. CONCLUSIONS: The incidence of delirium varied greatly with the type of procedure. The authors' logistic regression model showed that age and certain pre-existing neurologic conditions could predict delirium after cardiac surgery.

Pharmacological risk factors for delirium after cardiac surgery: a review.

PURPOSE: The objective of this review is to evaluate the literature on medications associated with delirium after cardiac surgery and potential prophylactic agents for preventing it. SOURCE: Articles were searched in MEDLINE, Cumulative Index to Nursing and Allied Health, and EMBASE with the MeSH headings: delirium, cardiac surgical procedures, and risk factors, and the keywords: delirium, cardiac surgery, risk factors, and drugs. Principle inclusion criteria include having patient samples receiving cardiac procedures on cardiopulmonary bypass, and using DSM-IV-TR criteria or a standardized tool for the diagnosis of delirium. PRINCIPAL FINDINGS: Fifteen studies were reviewed. Two single drugs (intraoperative fentanyl and ketamine), and two classes of drugs (preoperative antipsychotics and postoperative inotropes) were identified in the literature as being independently associated with delirium after cardiac surgery. Another seven classes of drugs (preoperative antihypertensives, anticholinergics, antidepressants, benzodiazepines, opioids, and statins, and postoperative opioids) and three single drugs (intraoperative diazepam, and postoperative dexmedetomidine and rivastigmine) have mixed findings. One drug (risperidone) has been shown to prevent delirium when taken immediately upon awakening from cardiac surgery. None of these findings was replicated in the studies reviewed. CONCLUSION: These studies have shown that drugs taken perioperatively by cardiac surgery patients need to be considered in delirium risk management strategies. While medications with direct neurological actions are clearly important, this review has shown that specific cardiovascular drugs may also require attention. Future studies that are methodologically consistent are required to further validate these findings and improve their utility.

An evaluation of a novel software tool for detecting changes in physiological monitoring.

BACKGROUND: We have developed a software tool (iAssist) to assist clinicians as they monitor the physiological data that guide their actions during anesthesia. The system tracks the statistical properties of multiple dynamic physiological processes and identifies new trend patterns. We report our initial evaluation of this tool (in pseudo real-time) and compare the detection of trend changes to a post hoc visual review of the full trend. We suggest a combination of criteria by which to evaluate the performance of monitoring devices that aim to enhance trend detection. METHODS: Nineteen children and 28 adults consented to be included in the study, encompassing more than 68 h of anesthesia. In each surgical case, an anesthesiologist reported all perceived clinical changes in monitoring in real-time. A trained observer simultaneously documented the verbally reported changes and every anesthesiologist action. The same cases were subsequently evaluated offline (in pseudo real-time) by a novel software tool (iAssist). Heart rate, end-tidal carbon dioxide, exhaled minute ventilation, and respiratory rate were modeled using a dynamic linear growth model whose noise distribution was estimated by an adaptive Kalman filter based on a recursive expectation-maximization method. Changes were detected by adaptive local Cumulative Sum testing. Changes in the mean arterial noninvasive blood pressures and oxygen saturation were detected using adaptive Cumulative Sum testing on a filtered residual from an exponentially weighted moving averaging filter. In post hoc analysis, each change detected by iAssist was graded independently by two clinicians using a graphical display of the whole case. Missed changes were recorded. RESULTS: The iAssist software tool detected 869 true positive changes (at an average of 12.76/h) with a sensitivity of 0.91 and positive predictive value of 0.87. The post hoc review identified 91 missed changes (at an average of 1.34/h), resulting in an overall ratio of true positive rates to false-negative rates of 9.55. The clinicians in real-time reported 209 changes in trend (at an average of 3.07/h). CONCLUSION: The algorithms perform favorably compared with a visual inspection of the complete trend. Further research is needed to identify when and how to draw the clinician's attention to these changes.

Incidence and risk factors for impaired mobility in older cardiac surgery patients during the early postoperative period.

AIM: Mobility issues in the early postoperative period result in poor functional outcomes and diminished quality of life for patients of advanced age. We determined the incidence of and risk factors for mobility issues in the early postoperative period in patients receiving open heart cardiac surgery. METHODS: A retrospective chart review was carried out on 396 patients receiving open heart coronary artery bypass grafts (CABG), valve replacements and combination CABG-valve replacements in a tertiary care hospital. Data on demographics, comorbidities, laboratory values, medications, anesthesia and postoperative care were abstracted. Mobility issues were considered present if they were documented in the medical chart. All pre- and intraoperative variables were entered into logistic regression. RESULTS: The mean age was 66.4 ± 11.9 years. In a subset of patients aged 75 years and older, the mean age was 79.8 ± 3.7 years. Mobility issues affected 36.9% of individuals from the total sample, and 47.6% of older patients. Increased age was a weak predictor in the total sample (OR 1.03), but was the only predictor in older adults (OR 1.1). The strongest predictors in the total sample were preoperative COPD (OR 2.7), congestive heart failure (CHF; OR 2.1), renal disease (OR 1.9), and pre-existing physical impairment (OR 1.8). Older patients with mobility issues were more likely to be discharged to acute care facilities, and had higher rates of mortality 3 years after surgery. CONCLUSIONS: Over one-third of cardiac surgery patients experienced early postoperative mobility issues. Older patients and those with COPD, CHF, renal disease or pre-existing physical impairments might benefit from preoperative consultation with physical therapists.

Case series: anesthesia for retrograde percutaneous aortic valve replacement--experience with the first 40 patients.

PURPOSE: To describe both the evolution and the main associated complications in the anesthetic management of the initial 40 patients at our centre who underwent percutaneous retrograde aortic valve replacement, a novel technique utilizing a catheter-guided femoral artery approach. CLINICAL FEATURES: With institutional Research Ethics Board approval, we retrospectively reviewed the medical records of the first 40 patients who underwent percutaneous retrograde aortic valve replacement between January 2005 and March 2006. Information obtained included patient characteristics, anesthetic management, details of the procedure, and complications. All procedures were scheduled to be performed in the cardiac catheterization laboratory. The first four patients received monitored anesthesia care, and the subsequent 36 underwent general anesthesia. There were no anesthesia-related adverse events. The prosthetic valve was placed successfully in 33/40 patients (83%). Median anesthetic time was 3.5 hr (range, 1.25-7.25 hr). Thirty-two/40 patients required vasopressor support. The most common, serious procedural complications were myocardial ischemia and arrhythmia following rapid ventricular pacing, hemorrhage from vascular injury secondary to the placement and removal of the large-bore sheath in the ilio-femoral artery, aortic rupture, and prosthetic valve maldeployment; 30-day mortality was 13% (n = 5/40). CONCLUSIONS: Percutaneous retrograde aortic valve replacement is a novel procedure that presents the anesthesiologist with unique challenges. Careful preoperative assessment, intraoperative monitoring appropriate for a major vascular procedure, and meticulous management of hemodynamics are imperative for a successful outcome. Serious complications, including major hemorrhage from vascular injury as well as arrhythmia and myocardial ischemia following rapid ventricular pacing, must be anticipated and managed in an expeditious fashion.