Daniel L. Helsten

Postoperative Delirium in a Substudy of Cardiothoracic Surgical Patients in the BAG-RECALL Clinical Trial

BACKGROUND:Postoperative delirium in the intensive care unit (ICU) is a frequent complication after cardiac or thoracic surgery and is associated with increased morbidity and mortality. METHODS:In this single-center substudy of the BAG-RECALL trial (NCT00682825), we screened patients after cardiac or thoracic surgery in the ICU twice daily for delirium using the Confusion Assessment Method for the ICU. The primary outcome was the incidence of delirium in patients who had been randomized to intraoperative Bispectral Index (BIS)-guided and end-tidal anesthetic concentration-guided depth of anesthesia protocols. As a secondary analysis, a Bayesian stochastic search variable selection strategy was used to rank a field of candidate risk factors for delirium, followed by binary logistic regression. RESULTS:Of 310 patients assessed, 28 of 149 (18.8%) in the BIS group and 45 of 161 (28.0%) in the end-tidal anesthetic concentration group developed postoperative delirium in the ICU (odds ratio 0.60, 95% confidence interval, 0.35–1.02, P= 0.058). Low average volatile anesthetic dose, intraoperative transfusion, ASA physical status, and European System for Cardiac Operative Risk Evaluation were identified as independent predictors of delirium. CONCLUSIONS:A larger randomized study should determine whether brain monitoring with BIS or an alternative method decreases delirium after cardiac or thoracic surgery. The association between low anesthetic concentration and delirium is a surprising finding and could reflect that patients with poor health are both more sensitive to the effects of volatile anesthetic drugs and are also more likely to develop postoperative delirium. Investigation of candidate methods to prevent delirium should be prioritized in view of the established association between postoperative delirium and adverse patient outcomes.

Increased Risk of Intraoperative Awareness in Patients with a History of Awareness

Background:Patients with a history of intraoperative awareness with explicit recall (AWR) are hypothesized to be at higher risk for AWR than the general surgical population. In this study, the authors assessed whether patients with a history of AWR (1) are actually at higher risk for AWR; (2) receive different anesthetic management; and (3) are relatively resistant to the hypnotic actions of volatile anesthetics. Methods:Patients with a history of AWR and matched controls from three randomized clinical trials investigating prevention of AWR were compared for relative risk of AWR. Anesthetic management was compared with the use of the Hotelling’s T2 statistic. A linear mixed model, including previously identified covariates, assessed the effects of a history of AWR on the relationship between end-tidal anesthetic concentration and bispectral index. Results:The incidence of AWR was 1.7% (4 of 241) in patients with a history of AWR and 0.3% (4 of 1,205) in control patients (relative risk = 5.0; 95% CI, 1.3–19.9). Anesthetic management did not differ between cohorts, but there was a significant effect of a history of AWR on the end-tidal anesthetic concentration versus bispectral index relationship. Conclusions:Surgical patients with a history of AWR are five times more likely to experience AWR than similar patients without a history of AWR. Further consideration should be given to modifying perioperative care and postoperative evaluation of patients with a history of AWR.

Association between intraoperative electroencephalographic suppression and postoperative mortality

BACKGROUND Low bispectral index values frequently reflect EEG suppression and have been associated with postoperative mortality. This study investigated whether intraoperative EEG suppression was an independent predictor of 90 day postoperative mortality and explored risk factors for EEG suppression. METHODS This observational study included 2662 adults enrolled in the B-Unaware or BAG-RECALL trials. A cohort was defined with >5 cumulative minutes of EEG suppression, and 1:2 propensity-matched to a non-suppressed cohort (≤5 min suppression). We evaluated the association between EEG suppression and mortality using multivariable logistic regression, and examined risk factors for EEG suppression using zero-inflated mixed effects analysis. RESULTS Ninety day postoperative mortality was 3.9% overall, 6.3% in the suppressed cohort, and 3.0% in the non-suppressed cohort {odds ratio (OR) [95% confidence interval (CI)]=2.19 (1.48-3.26)}. After matching and multivariable adjustment, EEG suppression was not associated with mortality [OR (95% CI)=0.83 (0.55-1.25)]; however, the interaction between EEG suppression and mean arterial pressure (MAP) <55 mm Hg was [OR (95% CI)=2.96 (1.34-6.52)]. Risk factors for EEG suppression were older age, number of comorbidities, chronic obstructive pulmonary disease, and higher intraoperative doses of benzodiazepines, opioids, or volatile anaesthetics. EEG suppression was less likely in patients with cancer, preoperative alcohol, opioid or benzodiazepine consumption, and intraoperative nitrous oxide exposure. CONCLUSIONS Although EEG suppression was associated with increasing anaesthetic administration and comorbidities, the hypothesis that intraoperative EEG suppression is a predictor of postoperative mortality was only supported if it was coincident with low MAP. CLINICAL TRIAL REGISTRATION NCT00281489 and NCT00682825.

Delirium after surgical and transcatheter aortic valve replacement is associated with increased mortality.

OBJECTIVE The purpose of this study was to determine the incidence and clinical significance of postoperative delirium (PD) in patients with aortic stenosis undergoing surgical aortic valve replacement (SAVR) or transcatheter aortic valve replacement (TAVR). METHOD Between 2010 and 2013, 427 patients underwent TAVR (n = 168) or SAVR (n = 259) and were screened for PD using the Confusion Assessment Method for the Intensive Care Unit. The incidence of PD in both treatment groups was determined and its association with morbidity and mortality was retrospectively compared. RESULTS PD occurred in 135 patients (32%) with a similar incidence between SAVR (33% [86 out of 259]) and TAVR (29% [49 out of 168]) (P = .40). TAVR by transfemoral approach had the lowest incidence of PD compared with SAVR (18% vs 33%; P = .025) or TAVR when performed by alternative access techniques (18% vs 35%; P = .02). Delirium was associated with longer initial intensive care unit stay (70 vs 27 hours), intensive care unit readmission (10% [14 out of 135] vs 2% [6 out of 292]), and longer hospital stay (8 vs 6 days) (P < .001 for all). PD was associated with increased mortality at 30 days (7% vs 1%; P < .001) and 1 year (21% vs 8%; P < .001). After multivariable adjustment, PD remained associated with increased 1-year mortality (hazard ratio, 3.02; 95% confidence interval, 1.75-5.23; P < .001). There was no interaction between PD and aortic valve replacement approach with respect to 1-year mortality (P = .12). Among propensity-matched patients (n = 170), SAVR-treated patients had a higher incidence of PD than TAVR-treated patients (51% vs 29%; P = .004). CONCLUSIONS PD occurs commonly after SAVR and TAVR and is associated with increased morbidity and mortality. Given the high incidence of PD and its associated adverse outcomes, further studies are needed to minimize PD and potentially improve patient outcomes.

Methodologic Considerations for Collecting Patient-reported Outcomes from Unselected Surgical Patients

Background:The impact of surgery on health is only appreciated long after hospital discharge. Furthermore, patients’ perceptions of postoperative health are not routinely ascertained. The authors instituted the Systematic Assessment and Targeted Improvement of Services Following Yearlong Surgical Outcomes Surveys (SATISFY-SOS) registry to evaluate patients’ postoperative health based on patient-reported outcomes (PROs). Methods:This article describes the methods of establishing the SATISFY-SOS registry from an unselected surgical population, combining perioperative PROs with information from electronic medical records. Patients enrolled during their preoperative visit were surveyed at enrollment, 30 days, and 1-yr postoperatively. Information on PROs, including quality of life, return to work, pain, functional status, medical complications, and cognition, was obtained from online, mail, or telephone surveys. Results:Using structured query language, 44,081 patients were identified in the electronic medical records as having visited the Center for Preoperative Assessment and Planning for preoperative assessment between July 16, 2012, and June 15, 2014, and 20,719 patients (47%) consented to participate in SATISFY-SOS. Baseline characteristics and health status were similar between enrolled and not enrolled patients. The response rate for the 30-day survey was 62% (8% e-mail, 73% mail, and 19% telephone) and for the 1-yr survey was 71% (13% e-mail, 78% mail, and 8% telephone). Conclusions:SATISFY-SOS demonstrates the feasibility of establishing a PRO registry reflective of a busy preoperative assessment center population, without disrupting clinical workflow. Our experience suggests that patient engagement, including informed consent and multiple survey modalities, enhances PROs collection from a large cohort of unselected surgical patients. Initiatives like SATISFY-SOS could promote quality improvement, enable efficient perioperative research, and facilitate outcomes that matter to surgical patients.

Electronic medical record interventions and recurrent perioperative antibiotic administration: a before-and-after study

PurposePerioperative antibiotics decrease rates of surgical-site infections. Numerous interventions have improved administration of the first antibiotic dose; however, failures in the administration of subsequent doses frequently occur. We hypothesized that modifications to the electronic medical record (EMR) would improve the administration of the second antibiotic dose and that such improvements would be sustained over time.MethodsThis historical cohort before-and-after study of multipronged alerts in the EMR analyzed 1,348 operations on adult patients. The operations lasted ≥ 240 min, utilized cefazolin as the perioperative antibiotic—constituting 1,348 second and 182 third intraoperative antibiotic doses—and did not involve cardiopulmonary bypass. A decision support intervention provided dosing recommendations when clinicians documented antibiotics. The reminder intervention displayed a continuous bar in the EMR, starting at the time the antibiotics were dosed and ending 15 min before subsequent doses were indicated. The primary endpoints of the study were the change in the proportion of correctly administered second dose of cefazolin, given in accordance with hospital guidelines in the month after implementing the intervention, and whether any improvements declined by three to seven months after implementation.ResultsPre-intervention, 51.4% of second doses of cefazolin were correctly administered. In the immediate post-intervention period, 68.5% were correctly administered, representing a significant absolute improvement of 17.1% (95% confidence interval, 8.1 to 26.1; P < 0.001). Rates did not decline over time; clinicians correctly administered 73.3% of doses in the delayed post-intervention period (P < 0.001 vs pre-intervention).ConclusionsThese inexpensive nonintrusive interventions to the EMR provided modest lasting improvements in proper administration of repeated doses of cefazolin. The fact that only approximately 70% compliance was reached highlights the difficulty in addressing this deficiency.RésuméObjectifLes antibiotiques administrés en période périopératoire réduisent les taux d’infections du site opératoire. De nombreuses interventions ont permis d’améliorer l’administration de la première dose antibiotique; toutefois, l’administration des doses subséquentes pose bien souvent problème. Nous avons émis l’hypothèse que des modifications apportées dans le dossier médical électronique (DME) amélioreraient l’administration de la deuxième dose antibiotique et que de telles améliorations se poursuivraient au fil du temps.MéthodeCette étude de cohorte historique avant-après portait sur l’ajout de messages d’alerte dans le DME et a évalué 1348 opérations réalisées chez des patients adultes. Les opérations ont duré ≥ 240 minutes; la céfazoline a été utilisée en tant qu’antibiotique périopératoire – pour un total de 1348 deuxièmes et de 182 troisièmes doses antibiotiques peropératoires; les opérations évaluées n’ont pas nécessité de circulation extracorporelle. Un message d’aide à la décision a émis des recommandations posologiques lorsque les cliniciens ont documenté l’usage d’antibiotiques. Le message de rappel affichait une barre en continu dans le DME, commençant au moment où les antibiotiques étaient dosés et se terminant 15 minutes avant que l’indication des doses subséquentes apparaisse. Les critères d’évaluation principaux de l’étude était le changement de proportion de deuxièmes doses de céfazoline adéquatement administrées, données selon les directives hospitalières au cours du mois suivant l’introduction de cette intervention, et le déclin – ou l’absence de déclin – de toute amélioration dans les trois à sept mois suivant l’introduction de cette intervention.RésultatsAvant l’intervention, 51,4 % des deuxièmes doses de céfazoline étaient administrées correctement. Dans la période suivant immédiatement l’intervention, 68,5 % des deuxièmes doses ont été correctement administrées, ce qui représente une amélioration absolue considérable de 17,1 % (intervalle de confiance 95 %, 8,1 à 26,1; P < 0,001). Ces taux n’ont pas baissé au fil du temps; les cliniciens ont correctement administré 73,3 % des doses dans la période post-intervention à plus long terme (P < 0,001 vs avant l’intervention).ConclusionCes interventions apportées au DME sont à la fois non intrusives et abordables, et ont procuré des améliorations durables et modestes à l’administration adéquate de doses répétées de céfazoline. Le fait qu’une compliance d’environ 70 % seulement ait été atteinte souligne la difficulté de régler ce manquement dans notre pratique.

Preoperative Falls Predict Postoperative Falls, Functional Decline, and Surgical Complications

Background Falls are common and linked to morbidity. Our objectives were to characterize postoperative falls, and determine whether preoperative falls independently predicted postoperative falls (primary outcome), functional dependence, quality of life, complications, and readmission. Methods This prospective cohort study included 7982 unselected patients undergoing elective surgery. Data were collected from the medical record, a baseline survey, and follow-up surveys approximately 30 days and one year after surgery. Results Fall rates (per 100 person-years) peaked at 175 (hospitalization), declined to 140 (30-day survey), and then to 97 (one-year survey). After controlling for confounders, a history of one, two, and ≥ three preoperative falls predicted postoperative falls at 30 days (adjusted odds ratios [aOR] 2.3, 3.6, 5.5) and one year (aOR 2.3, 3.4, 6.9). One, two, and ≥ three falls predicted functional decline at 30 days (aOR 1.2, 2.4, 2.4) and one year (aOR 1.3, 1.5, 3.2), along with in-hospital complications (aOR 1.2, 1.3, 2.0). Fall history predicted adverse outcomes better than commonly-used metrics, but did not predict quality of life deterioration or readmission. Conclusions Falls are common after surgery, and preoperative falls herald postoperative falls and other adverse outcomes. A history of preoperative falls should be routinely ascertained.

Preoperative Falls and Their Association with Functional Dependence and Quality of Life.

Background:No study has rigorously explored the characteristics of surgical patients with recent preoperative falls. Our objective was to describe the essential features of preoperative falls and determine whether they are associated with preoperative functional dependence and poor quality of life. Methods:This was an observational study involving 15,060 surveys from adult patients undergoing elective surgery. The surveys were collected between January 2014 and August 2015, with a response rate of 92%. Results:In the 6 months before surgery, 26% (99% CI, 25 to 27%) of patients fell at least once, and 12% (99% CI, 11 to 13%) fell at least twice. The proportion of patients who fell was highest among patients presenting for neurosurgery (41%; 99% CI, 36 to 45%). At least one fall-related injury occurred in 58% (99% CI, 56 to 60%) of those who fell. Falls were common in all age groups, but surprisingly, they did not increase monotonically with age. Middle-aged patients (45 to 64 yr) had the highest proportion of fallers (28%), recurrent fallers (13%), and severe fall-related injuries (27%) compared to younger (18 to 44 yr) and older (65+ yr) patients (P < 0.001 for each). A fall within 6 months was independently associated with preoperative functional dependence (odds ratio, 1.94; 99% CI, 1.68 to 2.24) and poor physical quality of life (odds ratio, 2.18; 99% CI, 1.88 to 2.52). Conclusions:Preoperative falls might be common and are possibly often injurious in the presurgical population, across all ages. A history of falls could enhance the assessment of preoperative functional dependence and quality of life.

Using machine learning techniques to develop forecasting algorithms for postoperative complications: Protocol for a retrospective study

Introduction Mortality and morbidity following surgery are pressing public health concerns in the USA. Traditional prediction models for postoperative adverse outcomes demonstrate good discrimination at the population level, but the ability to forecast an individual patient’s trajectory in real time remains poor. We propose to apply machine learning techniques to perioperative time-series data to develop algorithms for predicting adverse perioperative outcomes. Methods and analysis This study will include all adult patients who had surgery at our tertiary care hospital over a 4-year period. Patient history, laboratory values, minute-by-minute intraoperative vital signs and medications administered will be extracted from the electronic medical record. Outcomes will include in-hospital mortality, postoperative acute kidney injury and postoperative respiratory failure. Forecasting algorithms for each of these outcomes will be constructed using density-based logistic regression after employing a Nadaraya-Watson kernel density estimator. Time-series variables will be analysed using first and second-order feature extraction, shapelet methods and convolutional neural networks. The algorithms will be validated through measurement of precision and recall. Ethics and dissemination This study has been approved by the Human Research Protection Office at Washington University in St Louis. The successful development of these forecasting algorithms will allow perioperative healthcare clinicians to predict more accurately an individual patient’s risk for specific adverse perioperative outcomes in real time. Knowledge of a patient’s dynamic risk profile may allow clinicians to make targeted changes in the care plan that will alter the patient’s outcome trajectory. This hypothesis will be tested in a future randomised controlled trial.

Study protocol for the Anesthesiology Control Tower—Feedback Alerts to Supplement Treatments (ACTFAST-3) trial: a pilot randomized controlled trial in intraoperative telemedicine

Background: Each year, over 300 million people undergo surgical procedures worldwide. Despite efforts to improve outcomes, postoperative morbidity and mortality are common. Many patients experience complications as a result of either medical error or failure to adhere to established clinical practice guidelines. This protocol describes a clinical trial comparing a telemedicine-based decision support system, the Anesthesiology Control Tower (ACT), with enhanced standard intraoperative care. Methods: This study is a pragmatic, comparative effectiveness trial that will randomize approximately 12,000 adult surgical patients on an operating room (OR) level to a control or to an intervention group. All OR clinicians will have access to decision support software within the OR as a part of enhanced standard intraoperative care. The ACT will monitor patients in both groups and will provide additional support to the clinicians assigned to intervention ORs. Primary outcomes include blood glucose management and temperature management. Secondary outcomes will include surrogate, clinical, and economic outcomes, such as incidence of intraoperative hypotension, postoperative respiratory compromise, acute kidney injury, delirium, and volatile anesthetic utilization. Ethics and dissemination: The ACTFAST-3 study has been approved by the Human Resource Protection Office (HRPO) at Washington University in St. Louis and is registered at clinicaltrials.gov ( NCT02830126). Recruitment for this protocol began in April 2017 and will end in December 2018. Dissemination of the findings of this study will occur via presentations at academic conferences, journal publications, and educational materials.