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Alerting thresholds for the prevention of intraoperative awareness with explicit recall: a secondary analysis of the Michigan Awareness Control Study.

ABSTRACT: Intraoperative awareness with explicit recall is a potentially devastating complication of surgery that has been attributed to low anaesthetic concentrations in the vast majority of cases. Past studies have proposed the determination of an adequate dose for general anaesthetics that could be used to alert providers of potentially insufficient anaesthesia. However, there have been no systematic analyses of appropriate thresholds to develop population-based alerting algorithms for preventing intraoperative awareness.To identify a threshold for intraoperative alerting that could be applied for the prevention of awareness with explicit recall.Secondary analysis of a randomised controlled trial (Michigan Awareness Control Study).Three hospitals at a tertiary care centre in the USA.Unselected patients presenting for surgery under general anaesthesia.Alerts based on end-tidal anaesthetic concentration or bispectral index values.Using case and outcomes data from the primary study, end-tidal anaesthetic concentration and bispectral index values were analysed using Youden's index and c-statistics derived from a receiver operating characteristic curve to determine a specific alerting threshold for the prevention of awareness.No single population-based threshold that maximises sensitivity and specificity could be identified for the prevention of intraoperative awareness, using either anaesthetic concentration or bispectral index values. The c-statistic for anaesthetic concentration was 0.431?±?0.046, and 0.491?±?0.056 for bispectral index values.We could not derive a single population-based alerting threshold for the prevention of intraoperative awareness using either anaesthetic concentration or bispectral index values. These data indicate a need to move towards individualised alerting strategies in the prevention of intraoperative awareness.Primary trial registration (Michigan Awareness Control Study) ClinicalTrials.gov identifier: NCT00689091.

SUBMITTER: Shanks AM

PROVIDER: S-EPMC4737525 | biostudies-literature | 2015 May

REPOSITORIES: biostudies-literature

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Alerting thresholds for the prevention of intraoperative awareness with explicit recall: a secondary analysis of the Michigan Awareness Control Study.

Shanks Amy M AM Avidan Michael S MS Kheterpal Sachin S Tremper Kevin K KK Vandervest John C JC Cavanaugh John M JM Mashour George A GA

European journal of anaesthesiology 20150501 5

<h4>Background</h4>Intraoperative awareness with explicit recall is a potentially devastating complication of surgery that has been attributed to low anaesthetic concentrations in the vast majority of cases. Past studies have proposed the determination of an adequate dose for general anaesthetics that could be used to alert providers of potentially insufficient anaesthesia. However, there have been no systematic analyses of appropriate thresholds to develop population-based alerting algorithms f ...[more]

PMID: 25010744

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Project description:BackgroundThe incidence of intraoperative awareness with explicit recall is 1-2/1000 cases in the United States. The Bispectral Index monitor is an electroencephalographic method of assessing anesthetic depth that has been shown in one prospective study to reduce the incidence of awareness in the high-risk population. In the B-Aware trial, the number needed to treat in order to prevent one case of awareness in the high-risk population was 138. Since the number needed to treat and the associated cost of treatment would be much higher in the general population, the efficacy of the Bispectral Index monitor in preventing awareness in all anesthetized patients needs to be clearly established. This is especially true given the findings of the B-Unaware trial, which demonstrated no significant difference between protocols based on the Bispectral Index monitor or minimum alveolar concentration for the reduction of awareness in high risk patients.Methods/designTo evaluate efficacy in the general population, we are conducting a prospective, randomized, controlled trial comparing the Bispectral Index monitor to a non-electroencephalographic gauge of anesthetic depth. The total recruitment for the study is targeted for 30,000 patients at both low and high risk for awareness. We have developed a novel algorithm that is capable of real-time analysis of our electronic perioperative information system. In one arm of the study, anesthesia providers will receive an electronic page if the Bispectral Index value is >60. In the other arm of the study, anesthesia providers will receive a page if the age-adjusted minimum alveolar concentration is <0.5. Our minimum alveolar concentration algorithm is sensitive to both inhalational anesthetics and intravenous sedative-hypnotic agents.DiscussionAwareness during general anesthesia is a persistent problem and the role of the Bispectral Index monitor in its prevention is still unclear. The Michigan Awareness Control Study is the largest prospective trial of awareness prevention ever conducted.Trial registrationClinical Trial NCT00689091.

Project description:BackgroundAwareness with explicit recall of intra-operative events is a rare and distressing complication that may lead to severe psychological symptoms. Candidate depth of anesthesia monitors have been developed, partly with the aim of preventing this complication. Despite conflicting results from clinical trials and the lack of incisive validation, such monitors have enjoyed widespread clinical adoption, in particular the bispectral index. The American Society of Anesthesiologists has called for adequately powered and rigorously designed clinical trials to determine whether the use of such monitors decreases the incidence of awareness in various settings. The aim of this study is to determine with increased precision whether incorporating the bispectral index into a structured general anesthesia protocol decreases the incidence of awareness with explicit recall among a subset of surgical patients at increased risk for awareness and scheduled to receive an inhalation gas-based general anesthetic.Methods/designBAG-RECALL is a multi-center, randomized, controlled clinical trial, in which 6,000 patients are being assigned to bispectral index-guided anesthesia (target range, 40 to 60) or end-tidal anesthetic gas-guided anesthesia (target range, 0.7 to 1.3 age-adjusted minimum alveolar concentration). Postoperatively, patients are being assessed for explicit recall at two intervals (0 to 72 hours, and 30 days after extubation). The primary outcome of the trial is awareness with explicit recall. Secondary outcomes include postoperative mortality, psychological symptoms, intensive care and hospital length of stay, average anesthetic gas administration, postoperative pain and nausea and vomiting, duration of stay in the recovery area, intra-operative dreaming, and postoperative delirium.DiscussionThis trial has been designed to complement two other clinical trials: B-Unaware and MACS (ClinicalTrials.gov numbers, NCT00281489 and NCT00689091). With the large patient numbers and complementary rigorous designs, it is envisaged that pre-specified meta-analyses will address some of the outstanding controversies and questions relating to processed electroencephalography monitoring.Trial registrationClinicalTrials.gov Identifier: NCT00682825.

Project description:BackgroundElective surgery can have long-term psychological sequelae, especially for patients who experience intraoperative awareness. However, risk factors, other than awareness, for symptoms of posttraumatic stress disorder (PTSD) after surgery are poorly defined, and practical screening methods have not been applied to a broad population of surgical patients.MethodsThe Psychological Sequelae of Surgery study was a prospective cohort study of patients previously enrolled in the United States and Canada in 3 trials for the prevention of intraoperative awareness. The 68 patients who experienced definite or possible awareness were matched with 418 patients who denied awareness based on age, sex, surgery type, and awareness risk. Participants completed the PTSD Checklist-Specific (PCL-S) and/or a modified Mini-International Neuropsychiatric Interview telephone assessment to identify symptoms of PTSD and symptom complexes consistent with a PTSD diagnosis. We then used structural equation modeling to produce a composite PTSD score and examined potential risk factors.ResultsOne hundred forty patients were unreachable; of those contacted, 303 (88%) participated a median of 2 years postoperatively. Forty-four of the 219 patients (20.1%) who completed the PCL-S exceeded the civilian screening cutoff score for PTSD symptoms resulting from their surgery (15 of 35 [43%] with awareness and 29 of 184 [16%] without). Nineteen patients (8.7%; 5 of 35 [14%] with awareness and 14 of 184 [7.6%] without) both exceeded the cutoff and endorsed a breadth of symptoms consistent with the Diagnostic and Statistical Manual Fourth Edition diagnosis of PTSD attributable to their surgery. Factors independently associated with PTSD symptoms were poor social support, previous PTSD symptoms, previous mental health treatment, dissociation related to surgery, perceiving that one's life was threatened during surgery, and intraoperative awareness (all P ≤ 0.017). Perioperative dissociation was identified as a potential mediator for perioperative PTSD symptoms.ConclusionsEvents in the perioperative period can precipitate psychological symptoms consistent with subsyndromal and syndromal PTSD. We not only confirmed the high rate of postoperative PTSD in awareness patients but also identified a significant rate in matched nonawareness controls. Screening surgical patients, especially those with potentially mediating risk factors such as intraoperative awareness or perioperative dissociation, for postoperative PTSD symptoms with the PCL-S is practical and could promote early referral, evaluation, and treatment.

Project description:IntroductionFirearm-related deaths and injuries are ongoing public health issues in the United States. We reviewed a series of gun violence- and firearm-related injuries treated at a multi-campus community healthcare system in West Michigan to better understand the demographic and clinical characteristics of these injuries. We also studied hospital charges, and payers responsible, in an effort to identify stakeholders and opportunities for community- and hospital-based prevention.MethodsWe performed a retrospective review of firearm injuries treated at Mercy Health Muskegon (MHM) between May 1, 2015 and June 30, 2019. Demographic data, injury type, Injury Severity Score (ISS), anatomic location and organ systems involved, length of stay (LOS), mortality, time of year, and ZIP code in which the injury occurred were reviewed, as were hospital charges and payers responsible.ResultsOf those reviewed, 307 firearm-related injuries met inclusion criteria for the study. In 69.4% of cases the injury type was attempted murder or intent to do bodily harm. Accidental and self-inflicted injuries accounted for 25% of cases. There was a statistically significant difference in the mechanism of injury between Black and White patients with a higher proportion of Black men injured due to gun violence (P < 0.001). Median ISS was 8 and the most commonly injured organ system was musculoskeletal. Median LOS was one day. Self-inflicted firearm injuries had the highest rate of mortality (50%) followed by attempted murder (7%) and accidental discharge (3.1%; P < 0.001). Median hospital charge was $8,008. In 68% of cases, Medicaid was the payer. MHM received $4.98 million dollars in reimbursement from Medicaid; however, when direct and indirect costs were taken into account, a loss of $12,648 was observed.ConclusionFindings from this study reveal that young, Black men are the primary victims of gun violence-related injuries in our West Michigan service area. Hospital care of firearm-related injuries at MHM was predominantly paid for by Medicaid. Multiple stakeholders stand to benefit from funding and supporting community- and hospital-based prevention programs designed to reduce gun violence and firearm-related injuries in our service area.

Project description:BackgroundMedicaid expansion in Michigan, known as the Healthy Michigan Plan (HMP), emphasizes primary care and preventive services.ObjectiveEvaluate the impact of enrollment in HMP on access to and receipt of care, particularly primary care and preventive services.DesignTelephone survey conducted during January-November 2016 with stratified random sampling by income and geographic region (response rate = 53.7%). Logistic regression analyses accounted for sampling and nonresponse adjustment.Participants4090 HMP enrollees aged 19-64 with ≥ 12 months of HMP coverage MAIN MEASURES: Surveys assessed demographic factors, health, access to and use of health care before and after HMP enrollment, health behaviors, receipt of counseling for health risks, and knowledge of preventive services' copayments. Utilization of preventive services was assessed using Medicaid claims.Key resultsIn the 12 months prior to HMP enrollment, 33.0% of enrollees reported not getting health care they needed. Three quarters (73.8%) of enrollees reported having a regular source of care (RSOC) before enrollment; 65.1% of those reported a doctor's office/clinic, while 16.2% reported the emergency room. After HMP enrollment, 92.2% of enrollees reported having a RSOC; 91.7% had a doctor's office/clinic and 1.7% the emergency room. One fifth (20.6%) of enrollees reported that, before HMP enrollment, it had been over 5 years since their last primary care visit. Enrollees who reported a visit with their primary care provider after HMP enrollment (79.3%) were significantly more likely than those who did not report a visit to receive counseling about health behaviors, improved access to cancer screening, new diagnoses of chronic conditions, and nearly all preventive services. Enrollee knowledge that some services have no copayments was also associated with greater utilization of most preventive services.ConclusionsAfter enrolling in Michigan's Medicaid expansion program, beneficiaries reported less forgone care and improved access to primary care and preventive services.

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Alerting thresholds for the prevention of intraoperative awareness with explicit recall: a secondary analysis of the Michigan Awareness Control Study.

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Alerting thresholds for the prevention of intraoperative awareness with explicit recall: a secondary analysis of the Michigan Awareness Control Study.

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