Would You Rather: Quantifying Traumatic Brain Injury Survivor Perceptions of Functional Status Through Their Surrogates.

OBJECTIVE: To quantify health utilities of the Glasgow Outcome Scale-Extended (GOSE) states after actual traumatic brain injury (TBI). BACKGROUND: Recovery after TBI is measured using the GOSE, a validated clinical trial endpoint. A recent public survey quantified the health utilities of some GOSE states after hypothetical TBI as worse than death. However, no health utilities exist for disability after actual TBI. METHODS: This national computer-adaptive survey followed Enhancing the Quality and Transparency of Health Research-Checklist for Reporting Results of Internet E-Surveys guidelines and recruited adult TBI survivors (injury >1 year prior) through their available surrogates. Using a standard gamble approach in randomized order, participants gave preferences for post-TBI categorical health states ranging from GOSE 2 to GOSE 8. We calculated median (interquartile range) health utilities for each GOSE state, from -1 (worse than death) to 1 (full health), with 0 as reference (death, GOSE 1). RESULTS: Of 515 eligible, 298 surrogates (58%) consented and completed the scenarios on TBI survivors' behalf. TBI survivors had a current median GOSE 5 (3-7). GOSE 2, GOSE 3, and GOSE 4 were rated worse than death by 89%, 64%, and 38%, respectively. The relationship was nonlinear, and intervals were unequal between states, with a bimodal distribution for GOSE 4. CONCLUSIONS: In this index study of actual post-TBI disability, poor neurological outcomes represented by GOSE 2 to GOSE 4 were perceived as worse than death by at least one in 3 survivors. Similar to previously reported public perceptions after a hypothetical TBI, these long-term perceptions may inform earlier post-TBI shared decision-making, as well as help shape value-based research and quality of care. LEVEL OF EVIDENCE: Level II-economic and value-based evaluations.

In-hospital catatonia, delirium, and coma and mortality: Results from the delirium and catatonia prospective cohort investigation.

BACKGROUND: Catatonia, a form of acute brain dysfunction typically linked with severe affective and psychotic disorders, occurs in critical illness with delirium and coma. Delirium and coma are associated with mortality, though catatonia's relationship with mortality is unclear. We aim to describe whether catatonia, delirium, and coma are associated with mortality. METHODS: We enrolled a convenience cohort of critically ill adults (N = 378) at an academic medical center. We assessed catatonia, delirium, and coma using the Bush-Francis Catatonia Rating Scale, the Confusion Assessment Method for the Intensive Care Unit and the Richmond Agitation-Sedation Scale, respectively. We tested the associations between previous day brain dysfunction state occurrence with in-hospital and one-year mortality using multivariable time-dependent risk models. Additionally, we tested the association between brain dysfunction duration and one-year mortality. RESULTS: Catatonia was not associated with death on the day after diagnosis during hospitalization, and neither previous catatonia occurrence nor duration was associated with one-year mortality. Delirium was not associated with death on any day following diagnosis during hospitalization, and neither previous delirium occurrence nor duration was associated with one-year mortality. The occurrence of coma was associated with death on any day after diagnosis during hospitalization (HR 2.30,CI 1.19-4.44,p = 0.014), as well as through one year following hospital discharge (HR 1.68,CI 1.09-2.59,p = 0.02). CONCLUSIONS: Coma, but neither catatonia nor delirium, was associated with future day in-hospital and one-year mortality. More research is needed to understand catatonia's clinical impact. Delirium results differ from existing literature likely due to cohort demographics and size. Coma results highlight the prognostic significance of suppressed arousal while critically ill.

Dynamic predictors of in-hospital and 3-year mortality after traumatic brain injury: A retrospective cohort study.

BACKGROUND: Mortality risks after Traumatic Brain Injury (TBI) are understudied in critical illness. We sought to identify risks of mortality in critically ill patients with TBI using time-varying covariates. METHODS: This single-center, six-year (2006-2012), retrospective cohort study measured demographics, injury characteristics, and daily data of acute TBI patients in the Intensive Care Unit (ICU). Time-varying Cox proportional hazards models assessed in-hospital and 3-year mortality. RESULTS: Post-TBI ICU patients (n = 2664) experienced 20% in-hospital mortality (n = 529) and 27% (n = 706) 3-year mortality. Glasgow Coma Scale motor subscore (hazard ratio (HR) 0.58, p < 0.001), pupil reactivity (HR 3.17, p < 0.001), minimum glucose (HR 1.44, p < 0.001), mSOFA score (HR 1.81, p < 0.001), coma (HR 2.26, p < 0.001), and benzodiazepines (HR 1.38, p < 0.001) were associated with in-hospital mortality. At three years, public insurance (HR 1.78, p = 0.011) and discharge disposition (HR 4.48, p < 0.001) were associated with death. CONCLUSIONS: Time-varying characteristics influenced in-hospital mortality post-TBI. Socioeconomic factors primarily affect three-year mortality.

Physiologic responses to exercise in survivors of critical illness: an exploratory pilot study.

BACKGROUND: ICU survivors suffer from impaired physical function and reduced exercise capacity, yet the underlying mechanisms are poorly understood. The goal of this exploratory pilot study was to investigate potential mechanisms of exercise limitation using cardiopulmonary exercise testing (CPET) and 6-min walk testing (6MWT). METHODS: We enrolled adults aged 18 years or older who were treated for respiratory failure or shock in medical, surgical, or trauma ICUs at Vanderbilt University Medical Center (Nashville, TN, United States). We excluded patients with pre-existing cardiac dysfunction, a contraindication to CPET, or the need for supplemental oxygen at rest. We performed CPET and 6MWT 6 months after ICU discharge. We measured standard CPET parameters in addition to two measures of oxygen utilization during exercise (VO2-work rate slope and VO2 recovery half-time). RESULTS: We recruited 14 participants. Low exercise capacity (i.e., VO2Peak < 80% predicted) was present in 11 out of 14 (79%) with a median VO2Peak of 12.6 ml/kg/min [9.6-15.1] and 6MWT distance of 294 m [240-433]. In addition to low VO2Peak, CPET findings in survivors included low oxygen uptake efficiency slope, low oxygen pulse, elevated chronotropic index, low VO2-work rate slope, and prolonged VO2 recovery half-time, indicating impaired oxygen utilization with a hyperdynamic heart rate and ventilatory response, a pattern seen in non-critically ill patients with mitochondrial myopathies. Worse VO2-work rate slope and VO2 recovery half-time were strongly correlated with worse VO2Peak and 6MWT distance, suggesting that exercise capacity was potentially limited by impaired muscle oxygen utilization. CONCLUSIONS: These exploratory data suggest ICU survivors may suffer from impaired muscular oxygen metabolism due to mitochondrial dysfunction that impairs exercise capacity long-term. These findings should be further characterized in future studies that include direct assessments of muscle mitochondrial function in ICU survivors.

Prior Antibiotic Exposure Is Associated With Reoperation After Elective Non-colorectal Surgery.

BACKGROUND: Recent antibiotic exposure has previously been associated with poor outcomes following elective surgery. The purpose of this study is to evaluate the impact of prior recent antibiotic exposure in a multicenter cohort of Veterans Affairs patients undergoing elective non-colorectal surgery. METHODS: This is a retrospective cohort study of the Veterans Affairs Surgical Quality Improvement Program, including elective, non-cardiovascular, non-colorectal surgery from 2013 to 2017. Outpatient antibiotic exposure within 90 days prior to surgery was identified from the Veterans Affairs outpatient pharmacy database and matched with each case. Primary outcomes included serious complication, any complication, any infection, or surgical site infection. Secondary outcomes included 30-day mortality, length of stay, and Clostridioides difficile infection. RESULTS: Of 21,112 eligible patients, 2885 (13.7%) were exposed to antibiotics within 90 days prior to surgery with a duration of 7 (IQR: 5-10) days and prescribed 42 (IQR: 21-64) days prior to surgical intervention. Compared to non-exposed patients, exposed patients had higher unadjusted complication rates, increased length of stay, and rates of return to the operating. Exposure was independently associated with return to the operating room (OR: 1.39; 99% CI: 1.05-1.84). CONCLUSIONS: Among Veterans, recent antibiotic exposure within 90 days of elective surgery was associated with a 39% increase in the odds of return to the operating room. Further work is needed to evaluate the effects of antibiotic exposure and dysbiosis on surgical outcomes.

Higher Grade Glioma Increases the Risk of Postoperative Delirium: Deficient Brain Compensation Might Be a Potential Mechanism of Postoperative Delirium.

Objective: The brain compensation mechanism in postoperative delirium (POD) has not been reported. We uncovered the mechanism by exploring the association between POD and glioma grades, and the relationship between preoperative brain structural and functional compensation with POD in patients with frontal glioma. Methods: A total of 335 adult patients with glioma were included. The multivariable analysis examined the association between tumor grade and POD. Then, 20 patients with left frontal lobe glioma who had presurgical structural and functional MRI data and Montreal Cognitive Assessment (MoCA) in this cohort were analyzed. We measured the gray matter volume (GMV) and functional connectivity (FC) in patients with (n = 8) and without (n = 12) POD and healthy controls (HCs, n = 29) to detect the correlation between the structural and functional alteration and POD. Results: The incidence of POD was 37.3%. Multivariable regression revealed that high-grade glioma had approximately six times the odds of POD. Neuroimaging data showed that compared with HC, the patients with left frontal lobe glioma showed significantly increased GMV of the right dorsal lateral prefrontal cortex (DLPFC) in the non-POD group and decreased GMV of right DLPFC in the POD group, and the POD group exhibited significantly decreased FC of right DLPFC, and the non-POD group showed the increasing tendency. Partial correlation analysis showed that GMV in contralesional DLPFC were positively correlated with preoperative neurocognition, and the GMV and FC in contralesional DLPFC were negatively correlated with POD. Conclusions: Our findings suggested that insufficient compensation for injured brain regions involving cognition might be more vulnerable to suffering from POD.

The choices we make: Ethical challenges in trauma surgery.

BACKGROUND: Ethical issues in trauma surgery are commonplace but scarcely studied. We aim to characterize the ethical dilemmas trauma surgeons encounter in clinical practice and describe perceptions about the ability to manage these dilemmas and strategies they use to address them. METHODS: Members of a U.S. trauma society were electronically surveyed on handling ethically challenging scenarios. The survey instrument was developed using published ethics literature and iterative cognitive interviews. Domains included perceived frequency of encountering and self-efficacy of managing ethical situations in trauma surgery. Common situations were defined as those encountered monthly or weekly. Ethical problems were categorized within 7 larger categories: general ethics, autonomy, communication, justice, end-of-life, conflict, and other. Descriptive analyses were performed; group comparisons were analyzed using analysis of variance. RESULTS: Of 1,748 surveyed, 548 responded (30.6%) and 154 (28%) were female. Most were White, under 55 years age, had completed fellowship training, and were practicing at a level I or II trauma center. The most encountered ethical categories were generic ethics and communication (79%). Issues involving conflict were least frequent (21%). Respondents felt most uncomfortable with autonomy topics. Respondents with high self-efficacy in handling ethical situations were older, in practice ≥15 years, served on an ethics committee, and/or frequently experienced ethical challenges. CONCLUSION: Most trauma surgeons regularly encounter ethical challenges, especially those related to communication. Trauma surgeons encounter ethical issues involving conflict least often, and lowest self-efficacy scores with issues involving autonomy. Experienced trauma surgeons reported higher self-efficacy scores in managing ethical issues. Future work should examine how self-efficacy translates to observed behavior, and how trauma surgeons build and enhance their ethical skillsets in the care of the injured patient.

Developing a National Trauma Research Action Plan: Results from the Neurotrauma Research Panel Delphi Survey.

BACKGROUND: In 2016, the National Academies of Science, Engineering and Medicine called for the development of a National Trauma Research Action Plan. The Department of Defense funded the Coalition for National Trauma Research to generate a comprehensive research agenda spanning the continuum of trauma and burn care. Given the public health burden of injuries to the central nervous system, neurotrauma was one of 11 panels formed to address this recommendation with a gap analysis and generation of high-priority research questions. METHODS: We recruited interdisciplinary experts to identify gaps in the neurotrauma literature, generate research questions, and prioritize those questions using a consensus-driven Delphi survey approach. We conducted four Delphi rounds in which participants generated key research questions and then prioritized the importance of the questions on a 9-point Likert scale. Consensus was defined as 60% or greater of panelists agreeing on the priority category. We then coded research questions using an National Trauma Research Action Plan taxonomy of 118 research concepts, which were consistent across all 11 panels. RESULTS: Twenty-eight neurotrauma experts generated 675 research questions. Of these, 364 (53.9%) reached consensus, and 56 were determined to be high priority (15.4%), 303 were deemed to be medium priority (83.2%), and 5 were low priority (1.4%). The research topics were stratified into three groups-severe traumatic brain injury (TBI), mild TBI (mTBI), and spinal cord injury. The number of high-priority questions for each subtopic was 46 for severe TBI (19.7%), 3 for mTBI (4.3%) and 7 for SCI (11.7%). CONCLUSION: This Delphi gap analysis of neurotrauma research identified 56 high-priority research questions. There are clear areas of focus for severe TBI, mTBI, and spinal cord injury that will help guide investigators in future neurotrauma research. Funding agencies should consider these gaps when they prioritize future research. LEVEL OF EVIDENCE: Diagnostic Test or Criteria, Level IV.

Multicenter International Cohort Validation of a Modified Sequential Organ Failure Assessment Score Using the Richmond Agitation-sedation Scale.

OBJECTIVE: In a multicenter, international cohort, we aimed to validate a modified Sequential Organ Failure Assessment (mSOFA) using the Richmond Agitation-Sedation Scale, hypothesized as comparable to the Glasgow Coma Scale (GCS)-based Sequential Organ Failure Assessment (SOFA). SUMMARY BACKGROUND DATA: The SOFA score, whose neurologic component is based on the GCS, can predict intensive care unit (ICU) mortality. But, GCS is often missing in lieu of other assessments, such as the also reliable and validated Richmond Agitation Sedation Scale (RASS). Single-center data suggested an RASS-based SOFA (mSOFA) predicted ICU mortality. METHODS: Our nested cohort within the prospective 2016 Fourth International Study of Mechanical Ventilation contains 4120 ventilated patients with daily RASS and GCS assessments (20,023 patient-days, 32 countries). We estimated GCS from RASS via a proportional odds model without adjustment. ICU mortality logistic regression models and c-statistics were constructed using SOFA (measured GCS) and mSOFA (measured RASS-estimated GCS), adjusted for age, sex, body-mass index, region (Europe, USA-Canada, Latin America, Africa, Asia, Australia-New Zealand), and postoperative status (medical/surgical). RESULTS: Cohort-wide, the mean SOFA=9.4+/-2.8 and mean mSOFA = 10.0+/-2.3, with ICU mortality = 31%. Mean SOFA and mSOFA similarly predicted ICU mortality (SOFA: AUC = 0.784, 95% CI = 0.769-0.799; mSOFA: AUC = 0.778, 95% CI = 0.763-0.793, P = 0.139). Across models, other predictors of mortality included higher age, female sex, medical patient, and African region (all P < 0.001). CONCLUSIONS: We present the first SOFA modification with RASS in a "real-world" international cohort. Estimating GCS from RASS preserves predictive validity of SOFA to predict ICU mortality. Alternative neurologic measurements like RASS can be viably integrated into severity of illness scoring systems like SOFA.

Association of postoperative delirium with cognitive outcomes: A meta-analysis.

STUDY OBJECTIVE: To determine the association between postoperative delirium (POD) and cognitive outcomes at least 1 month after surgery in elderly patients, and synthesize the dynamic risk trajectory of cognition impairment after POD. DESIGN: Meta-analysis searching PubMed, Cochrane and EMBASE from inception to November 1, 2020. The terms postoperative delirium, delirium after surgery, postsurgical delirium, postoperative cogniti*, postoperative cognitive dysfunction, postoperative cognition decline, cognitive decline, cognitive impair* and dement* were searched alone or in combination. MEASUREMENTS: Inclusion criteria were prospective cohort studies investigating the association between POD and cognitive outcomes in patients aged ≥60 years underwent surgery. The primary outcome was the association between POD and cognitive outcomes at 1 or more months after surgery. We considered cognitive outcomes measured up to 12 months after surgery as short-term and beyond 12 months as long-term. Two authors performed the study screening, data extraction and quality assessments. Effect sizes were calculated as Hedges g or Odds ratio (OR) based on random- and fixed-effects models. Meta-regression was conducted to analyze the role of potential contributors to heterogeneity. MAIN RESULTS: Eighteen studies were included. Our result showed a significant and medium association between POD and cognitive outcomes after at least 1 month postoperatively (g = 0.61 95% CI 0.43-0.79; I2 = 65.1%), indicating that patients with POD were associated with worse cognitive outcomes. The association of POD with short- and long-term cognitive impairment were also both significant (short-term: g = 0.46 95% CI 0.24-0.68; I2 = 53.1%; and long-term: g = 0.82 95% CI 0.57-1.06; I2 = 57.1%). A multivariate meta-regression suggested that age and measure of delirium were significant sources of heterogeneity. POD was also associated with the significant risk for dementia (OR = 6.08 95% CI 3.80-9.72; I2 = 0) as well as attention (OR = 1.74 95% CI 1.13-2.68; I2 = 0), executive (OR = 1.33 95% CI 1.00-1.80; I2 = 0) and memory impairment (OR = 1.59 95% CI 1.20-2.10; I2 = 43.0%). Additionally, our results showed that the risk trajectory for cognitive decline associated with POD within five years after surgery revealed exponential growth. CONCLUSIONS: This is the first meta-analysis quantifying the association between POD and cognitive outcomes. Our results showed that POD was significantly associated with worse cognitive outcomes, including short- and long-term cognitive outcomes following surgery.

Regional ethics of surgeon resuscitation for organ transplantation after lethal injury.

BACKGROUND: Trauma patients may present with nonsurvivable injuries, which could be resuscitated for future organ transplantation. Trauma surgeons face an ethical dilemma of deciding whether, when, and how to resuscitate a patient who will not directly benefit from it. As there are no established guidelines to follow, we aimed to describe resuscitation practices for organ transplantation; we hypothesized that resuscitation practices vary regionally. METHOD: Over a 3-month period, we surveyed trauma surgeons practicing in Levels I and II trauma centers within a single state using an instrument to measure resuscitation attitudes and practices for organ preservation. Descriptive statistics were calculated for practice patterns. RESULTS: The survey response rate was 51% (31/60). Many (81%) had experience with resuscitations where the primary goal was to preserve potential for organ transplantation. Many (90%) said they encountered this dilemma at least monthly. All respondents were willing to intubate; most were willing to start vasopressors (94%) and to transfuse blood (84%) (range, 1 unit to >10 units). Of respondents, 29% would resuscitate for ≥24 hours, and 6% would perform a resuscitative thoracotomy. Respect for patients' dying process and future organ quality were the factors most frequently considered very important or important when deciding to stop or forgo resuscitation, followed closely by concerns about excessive resource use. CONCLUSION: Trauma surgeons' regional resuscitation practices vary widely for this patient population. This variation implies a lack of professional consensus regarding initiation and extent of resuscitations in this setting. These data suggest this is a common clinical challenge, which would benefit from further study to determine national variability, areas of equipoise, and features amenable to practice guidelines.

Worse Than Death: Survey of Public Perceptions of Disability Outcomes After Hypothetical Traumatic Brain Injury.

OBJECTIVE: The aim of this study was to determine the health utility states of the most commonly used traumatic brain injury (TBI) clinical trial endpoint, the Extended Glasgow Outcome Scale (GOSE). SUMMARY BACKGROUND DATA: Health utilities represent the strength of one's preferences under conditions of uncertainty. There are insufficient data to indicate how an individual would value levels of disability after a TBI. METHODS: This was a cross-sectional web-based online convenience sampling adaptive survey. Using a standard gamble approach, participants evaluated their preferences for GOSE health states 1 year after a hypothetical TBI. The categorical GOSE was studied from vegetative state (GOSE2) to upper good recovery (GOSE8). Median (25th percentile, 75th percentile) health utility values for different GOSE states after TBI, ranging from -1 (worse than death) to 1 (full health), with 0 as reference (death). RESULTS: Of 3508 eligible participants, 3235 (92.22%) completed the survey. Participants rated lower GOSE states as having lower utility, with some states rated as worse than death, though the relationship was nonlinear and intervals were unequal between health states. Over 75% of participants rated a vegetative state (GOSE2, absence of awareness and bedridden) and about 50% rated lower severe disability (GOSE3, housebound needing all-day assistance) as conditions worse than death. CONCLUSIONS: In the largest investigation of public perceptions about post-TBI disability, we demonstrate unequally rated health states, with some states perceived as worse than death. Although limited by selection bias, these results may guide future comparative-effectiveness research and shared medical decision-making after neurologic injury.

Socioeconomic Factors and Intensive Care Unit-Related Cognitive Impairment.

OBJECTIVE: We aimed to identify socioeconomic and clinical risk factors for post-intensive care unit (ICU)-related long-term cognitive impairment (LTCI). SUMMARY BACKGROUND DATA: After delirium during ICU stay, LTCI has been increasingly recognized, but without attention to socioeconomic factors. METHODS: We enrolled a prospective, multicenter cohort of ICU survivors with shock or respiratory failure from surgical and medical ICUs across 5 civilian and Veteran Affairs (VA) hospitals from 2010 to 2016. Our primary outcome was LTCI at 3- and 12 months post-hospital discharge defined by the Repeatable Battery for Assessment of Neuropsychological Symptoms (RBANS) global score. Covariates adjusted using multivariable linear regression included age, sex, race, AHRQ socioeconomic index, Charlson comorbidity, Framingham stroke risk, Sequential Organ Failure Assessment, duration of coma, delirium, hypoxemia, sepsis, education level, hospital type, insurance status, discharge disposition, and ICU drug exposures. RESULTS: Of 1040 patients, 71% experienced delirium, and 47% and 41% of survivors had RBANS scores >1 standard deviation below normal at 3- and 12 months, respectively. Adjusted analysis indicated that delirium, non-White race, lower education, and civilian hospitals (as opposed to VA), were associated with at least a half standard deviation lower RBANS scores at 3- and 12 months (P ≤ 0.03). Sex, AHRQ socioeconomic index, insurance status, and discharge disposition were not associated with RBANS scores. CONCLUSIONS: Socioeconomic and clinical risk factors, such as race, education, hospital type, and delirium duration, were linked to worse PICS ICU-related, LTCI. Further efforts may focus on improved identification of higher-risk groups to promote survivorship through emerging improvements in cognitive rehabilitation.

Frailty and Prognostication in Geriatric Surgery and Trauma.

Frailty is a predominant predictor of poor outcomes in older populations. This article presents a review of the concept of frailty and its role for prognostication among geriatric trauma and surgery patients. We discuss models of frailty defined in the scientific literature, emphasizing that frailty is a process of biologic aging. We emphasize the importance of screening, assessment, and inclusion of frailty indices for the development and use of prognostication instruments/tools in the population of interest. Finally, we discuss best practices for the delivery of prognostic information in acute care settings and specific recommendations for trauma and surgical care settings.

EAST Multicenter Trial on targeted temperature management for hanging-induced cardiac arrest.

BACKGROUND: We sought to determine the outcome of suicidal hanging and the impact of targeted temperature management (TTM) on hanging-induced cardiac arrest (CA) through an Eastern Association for the Surgery of Trauma (EAST) multicenter retrospective study. METHODS: We analyzed hanging patient data and TTM variables from January 1992 to December 2015. Cerebral performance category score of 1 or 2 was considered good neurologic outcome, while cerebral performance category score of 3 or 4 was considered poor outcome. Classification and Regression Trees recursive partitioning was used to develop multivariate predictive models for survival and neurologic outcome. RESULTS: A total of 692 hanging patients from 17 centers were analyzed for this study. Their overall survival rate was 77%, and the CA survival rate was 28.6%. The CA patients had significantly higher severity of illness and worse outcome than the non-CA patients. Of the 175 CA patients who survived to hospital admission, 81 patients (46.3%) received post-CA TTM. The unadjusted survival of TTM CA patients (24.7% vs 39.4%, p < 0.05) and good neurologic outcome (19.8% vs 37.2%, p < 0.05) were worse than non-TTM CA patients. However, when subgroup analyses were performed between those with an admission Glasgow Coma Scale score of 3 to 8, the differences between TTM and non-TTM CA survival (23.8% vs 30.0%, p = 0.37) and good neurologic outcome (18.8% vs 28.7%, p = 0.14) were not significant. Targeted temperature management implementation and post-CA management varied between the participating centers. Classification and Regression Trees models identified variables predictive of favorable and poor outcome for hanging and TTM patients with excellent accuracy. CONCLUSION: Cardiac arrest hanging patients had worse outcome than non-CA patients. Targeted temperature management CA patients had worse unadjusted survival and neurologic outcome than non-TTM patients. These findings may be explained by their higher severity of illness, variable TTM implementation, and differences in post-CA management. Future prospective studies are necessary to ascertain the effect of TTM on hanging outcome and to validate our Classification and Regression Trees models. LEVEL OF EVIDENCE: Therapeutic study, level IV; prognostic study, level III.