Therapeutic Hypothermia Utilization Research Articles

A Survey on the Management of Patients with Severe Traumatic Brain Injury During Pregnancy: The MAMA Study.

Trauma, including traumatic brain injury (TBI), is the leading cause of nonobstetric maternal mortality during pregnancy. Few data are available regarding the optimal management of pregnant patients with TBI, leading to a lack of dedicated guidelines. We performed an international survey to examine the management of severe TBI in pregnant patients, focusing on monitoring, therapy, and intensive care practices. This survey, endorsed by the World Society of Emergency Surgery, was composed of a questionnaire with 79 items divided into four sections: (1) general information (items 1-7), (2) management of the maternal-fetal unit (items 8-43), (3) management of intracranial hypertension (items 44-76), and (4) specific considerations (items 77-79). One hundred and twenty-two physicians from 110 centers in 35 countries responded. The main findings related to TBI care in pregnant patients included the following: (1) a lack of availability of a specific TBI protocol in pregnancy; (2) an increase in the utilization of magnetic resonance imaging as the primary neuroimaging tool; (3) higher hemoglobin thresholds for transfusion; and (4) a lower utilization of therapeutic hypothermia, neuromuscular blocking agents, and barbiturate coma. We also report large variability in the timing of cesarean section in pregnant patients with TBI (≥ 23weeks of gestation) needing an emergency craniotomy (simultaneously 23% vs. later cesarean section 50.8%). Great variability in the management of pregnant patients with severe TBI was identified worldwide from the results of our survey. These findings, highlighting the lack of robust evidence on this topic, will be helpful to stimulate future investigations and to promote educational efforts on this difficult scenario.

Post Cardiac Arrest Care in the Cardiac Intensive Care Unit.

Cardiac arrests constitute a leading cause of mortality in the adult population and cardiologists are often tasked with the management of patients following cardiac arrest either as a consultant or primary provider in the cardiac intensive care unit. Familiarity with evidence-based practice for post-cardiac arrest care is a requisite for optimizing outcomes in this highly morbid group. This review will highlight important concepts necessary to managing these patients. Emerging evidence has further elucidated optimal care of post-arrest patients including timing for routine coronary angiography, utility of therapeutic hypothermia, permissive hypercapnia, and empiric aspiration pneumonia treatment. The complicated state of multi-organ failure following cardiac arrest needs to be carefully optimized by the clinician to prevent further neurologic injury and promote systemic recovery. Future studies should be aimed at understanding if these findings extend to specific patient populations, especially those at the highest risk for poor outcomes.

Therapeutic Hypothermia for Neonatal Encephalopathy in Low- and Middle-Income Countries: A Meta-Analysis

Background: Perinatal asphyxia and hypoxic-ischemic encephalopathy (HIE) represent substantial sources of neonatal morbidity and mortality in low- and middle-income countries (LMICs), leading to high rates of adverse long-term neurological outcomes. Methods: A systematic review with meta-analysis of randomized controlled trials in LMICs was conducted. PubMed, Scopus, Web of Science, CENTRAL, ClinicalTrials.gov, and Google Scholar were searched from inception to August 20, 2021. The population of the study consisted of neonates with gestational age ≥34 weeks and HIE. The main endpoints were overall mortality and the composite outcome of death or severe disability. The certainty of evidence was evaluated with the GRADE approach. Results: Ten studies were included comprising 1,293 neonates. Some concerns of bias were raised due to the nonblinded nature of the intervention. The risk of death was similar between the two groups (risk ratio [RR]: 0.78, 95% confidence interval [CI]: 0.52–1.18). No significant differences were observed in the composite outcome of death or severe disability between the two groups (RR: 0.78, 95% CI: 0.56–1.10, very low quality of evidence). Furthermore, no significant differences were observed in the endpoints of sepsis, shock, acute kidney injury, major arrhythmia, and length of hospital stay. Therapeutic hypothermia was associated with significantly higher risk of thrombocytopenia (RR: 2.13, 95% CI: 1.34–3.38) and clinically significant hemorrhage (RR: 1.57, 95% CI: 1.25–1.97). Conclusion: Therapeutic hypothermia probably results in little to no difference in clinical outcomes among neonates with HIE in LMICs. Further large-scale research targeting proper patient selection is needed to elucidate the utility of therapeutic hypothermia in resource-limited settings. Protocol Registration: The protocol of the study has been prospectively registered by Prospero, CRD42021272284.

Utilization of Therapeutic Hypothermia and Neurological Injury in Neonates with Mild Hypoxic-Ischemic Encephalopathy: A Report from Children's Hospital Neonatal Consortium.

This study was aimed to describe utilization of therapeutic hypothermia (TH) in neonates presenting with mild hypoxic-ischemic encephalopathy (HIE) and associated neurological injury on magnetic resonance imaging (MRI) scans in these infants. Neonates ≥ 36 weeks' gestation with mild HIE and available MRI scans were identified. Mild HIE status was assigned to hyper alert infants with an exaggerated response to arousal and mild HIE as the highest grade of encephalopathy recorded. MRI scans were dichotomized as "injury" versus "no injury." A total of 94.5% (257/272) neonates with mild HIE, referred for evaluation, received TH. MRI injury occurred in 38.2% (104/272) neonates and affected predominantly the white matter (49.0%, n = 51). Injury to the deep nuclear gray matter was identified in (10.1%) 20 infants, and to the cortex in 13.4% (n = 14 infants). In regression analyses (odds ratio [OR]; 95% confidence interval [CI]), history of fetal distress (OR = 0.52; 95% CI: 0.28-0.99) and delivery by caesarian section (OR = 0.54; 95% CI: 0.31-0.92) were associated with lower odds, whereas medical comorbidities during and after cooling were associated with higher odds of brain injury (OR = 2.31; 95% CI: 1.37-3.89). Majority of neonates with mild HIE referred for evaluation are being treated with TH. Odds of neurological injury are over two-fold higher in those with comorbidities during and after cooling. Brain injury predominantly involved the white matter. · Increasingly, neonates with mild HIE are being referred for consideration for hypothermia therapy.. · Drift in clinical practice shows growing number of neonates treated with hypothermia as having mild HIE.. · MRI data show that 38% of neonates with mild HIE have brain injury, predominantly in the white matter..

Outcomes and Utilization of Therapeutic Hypothermia in Post-Cardiac Arrest Patients in Teaching Versus Non-Teaching Hospitals: Retrospective Study of the Nationwide Inpatient Sample Database (2016).

BackgroundUsing therapeutic hypothermia (TH) reduces the core body temperature of survivors of cardiac arrest to minimize the neurological damage caused by severe hypoxia. The TH protocol is initiated following return of spontaneous circulation (ROSC) in non-responsive patients. Clinical trials examining this technique have shown significant improvement in neurological function among survivors of cardiac arrests. Though there is strong evidence to support TH use to improve the neurologic outcomes in shockable and nonshockable rhythms, predictors of TH utilization are not well-characterized. Our study tried to evaluate TH utilization, as well as the effect of the teaching status of hospitals, on outcomes, including mortality, length of stay, and total hospitalization charges.MethodWe conducted a retrospective analysis of the Healthcare Cost and Utilization Project - Nationwide Inpatient Sample (HCUP-NIS) database. Patients with an admitting diagnosis of cardiac arrest, as identified by the corresponding International Classification of Disease, 10th Revision (ICD-10) code for the year 2016 were analyzed. In addition, we identified TH using the ICD-10 procedure code. A weighted descriptive analysis was performed to generate national estimates. Groups of patients admitted to teaching hospitals were compared to those admitted in non-teaching hospitals. Patients were stratified by age, sex, race, and demographic and clinical data, including the Charlson Comorbidity Index (CCI), for these two groups, and statistical analysis was done for the primary outcome, in-hospital mortality, as well as the secondary outcomes, including length of stay (LOS) and total hospitalization charges. Fisher’s exact test was used to compare proportions and student’s t-test for continuous variables. Statistical analysis was completed by linear regression analysis.ResultsA total of 13,780 patients met the inclusion criteria for cardiac arrest admission. The number of patients with cardiac arrest admitted to a teaching hospital was 9285. A total of 670 patients received TH, with 495 admissions to teaching hospitals. The population of females in the hypothermia group was 270. The mean age of patients received TH was 59.4 years. In patients who received TH, 65% were Caucasians followed by Hispanics (16%), with no significant statistical racial differences in groups (p=0.30). The majority of patients with TH in both groups (teaching vs. non-teaching admissions) had Medicare (58.8% vs 49.5%; p=0.75). Hospitals in the southern region had the most admissions in both groups (45.7% and 31.3%), with the northeast region having the least non-teaching hospital admissions (8.5%) and approximately similar teaching hospital admissions in other regions (~22%) (p=0.27). The total number of deaths in this group was 510, out of which 370 were in a teaching hospital. After adjusting for age, sex, race, income, the CCI, hospital location, and bed size, mortality was not significantly different between these two groups (p=0.797). We found increased LOS in patients admitted to teaching hospitals (p=0.021). With a p-value of 0.097, there were no differences in total hospitalization charges in both groups.ConclusionThere were no significant differences in mortality or total hospitalization charge between patients admitted with cardiac arrest to a teaching hospital and received TH as compared to a non-teaching hospital although patients admitted to teaching hospitals stayed longer.

The impact of therapeutic hypothermia in elderly out-of-hospital cardiac arrest: A multicenter retrospective observational propensity-matched study

Background: The therapeutic hypothermia protocol for out of hospital cardiac arrest is not standardized and the decision to apply therapeutic hypothermia relies on a physician’s judgment. Elderly patients who rely on this judgment are less likely to receive therapeutic hypothermia. Objectives: This study aimed to provide an analysis of the impact and utility of therapeutic hypothermia on elderly out of hospital cardiac arrest. Methods: This was a multicenter, retrospective, observational, registry-based study from 2007 to 2012. Adults who suffered out-of-hospital cardiac arrest and were treated with therapeutic hypothermia were included. We divided the patients into a group of elderly patients 65 years or older and a group of young adults under 65 years old and compared the neurologic outcomes and adverse events after one-to-one matching by propensity score. Results: In total, 930 patients were enrolled in the study. Among these patients, 343 were ⩾65 years, while 587 were <65 years. Of the adverse events in therapeutic hypothermia, hyperglycemia (51.31%), hypotension (41.98%) during cooling was more frequent in aged ⩾65 years and rebound hyperthermia (7.14%) and hypotension (29.93%) during rewarming. After propensity score matching was applied to all subjects of the study, 247 matched pairs of patients were available. The two groups showed no statistically significant difference in the adverse events during therapeutic hypothermia. Conclusion: Elderly patients exhibited a decreased survival to hospital discharge and good neurologic outcomes. The two groups showed no differences in the frequency of adverse events during therapeutic hypothermia, when comparing in a propensity score matching cohort analysis.

Abstract 105: Utilization of Therapeutic Hypothermia Post Cardiac Arrest and Outcomes in Teaching vs Nonteaching Hospital: A Retrospective Study of Nationwide Inpatient Sample (NIS) Database

Introduction: Therapeutic Hypothermia (TH) is a measure to reduce the core body temperature of survivors of cardiac arrest, to further minimize neurological damage caused by severe hypoxia. Clinical trials have shown significant improvement in neurological function among survivors of cardiac arrest received TH. Methods: We conducted a retrospective analysis of the Nationwide Inpatient Sample (HCUP-NIS) 2016 database. Patients admitted with a principal diagnosis of cardiac arrest who underwent TH were identified using the ICD-10 codes. A weighted descriptive analysis was performed to generate national estimates. Group of patients admitted to teaching hospitals were compared to those admitted to non-teaching hospitals. Patients were stratified by age, sex, race, demographic and clinical data including Charlson comorbidity index for these two groups and compared for the primary outcome, in-hospital mortality and secondary outcomes of length of stay (LOS) and total hospitalization charges. Analyses were done using STATA statistical software. Results: In 2016 total 13780 patients met inclusion criteria out of which half were female. Mean age was 64 years. Admissions to teaching hospital were 9285. Total 670 patients received TH, of which 74% were in teaching hospitals. Group who received therapeutic hypothermia, majority were Caucasians (65%) followed by Hispanics (16%) (p=0.30). Patients who received TH were majority Medicare (58.8% vs 49.5%; p=0.75). Southern hospitals had the most admissions in both groups (45.7% and 31.3%); Northeast region had the least non-teaching hospital admissions (8.5%). Total deaths in TH group were 510, 73% were in teaching hospitals. After adjusting for age, sex, race, income, charlson index, hospital location, and bed-size, there was no statistical significant difference in mortality , LOS and total charges between these two groups (p=0.82, p=0.24 and p=0.67 respectively). Interestingly there was 35% increase in adjusted odds for mortality of cardiac arrest patients in teaching hospitals (p=0.005). Conclusions: Among patients admitted with cardiac arrest and undergoing TH there were no significant differences in mortality, LOS or total hospitalization charges between teaching and non-teaching hospitals.

Racial Differences In Hospital Utilization Of Therapeutic Hypothermia Among Cardiac Arrest Patients In United States (P2.9-074)

Racial Differences In Hospital Utilization Of Therapeutic Hypothermia Among Cardiac Arrest Patients In United States (P2.9-074)

National Trends in Utilization of Therapeutic Hypothermia for Cardiac Arrest: National Inpatient Sample Study 2008–2014 (P2.9-070)

National Trends in Utilization of Therapeutic Hypothermia for Cardiac Arrest: National Inpatient Sample Study 2008–2014 (P2.9-070)

A New Vision for Therapeutic Hypothermia in the Era of Targeted Temperature Management: A Speculative Synthesis.

Three decades of animal studies have reproducibly shown that hypothermia is profoundly cerebroprotective during or after a central nervous system (CNS) insult. The success of hypothermia in preclinical acute brain injury has not only fostered continued interest in research on the classic secondary injury mechanisms that are prevented or blunted by hypothermia but has also sparked a surge of new interest in elucidating beneficial signaling molecules that are increased by cooling. Ironically, while research into cold-induced neuroprotection is enjoying newfound interest in chronic neurodegenerative disease, conversely, the scope of the utility of therapeutic hypothermia (TH) across the field of acute brain injury is somewhat controversial and remains to be fully defined. This has led to the era of Targeted Temperature Management, which emphasizes a wider range of temperatures (33–36°C) showing benefit in acute brain injury. In this comprehensive review, we focus on our current understandings of the novel neuroprotective mechanisms activated by TH, and discuss the critical importance of developmental age germane to its clinical efficacy. We review emerging data on four cold stress hormones and three cold shock proteins that have generated new interest in hypothermia in the field of CNS injury, to create a framework for new frontiers in TH research. We make the case that further elucidation of novel cold responsive pathways might lead to major breakthroughs in the treatment of acute brain injury, chronic neurological diseases, and have broad potential implications for medicines of the distant future, including scenarios such as the prevention of adverse effects of long-duration spaceflight, among others. Finally, we introduce several new phrases that readily summarize the essence of the major concepts outlined by this review—namely, Ultramild Hypothermia, the “Responsivity of Cold Stress Pathways,” and “Hypothermia in a Syringe.”

Response to Letter Regarding Article, “The Utility of Therapeutic Hypothermia for Post–Cardiac Arrest Syndrome Patients With an Initial Nonshockable Rhythm”

Thank you for the opportunity to respond to Dr Chan’s insightful comments regarding our article, “The Utility of Therapeutic Hypothermia for Post–Cardiac Arrest Syndrome Patients With an Initial Nonshockable Rhythm.”1 In this article, we used propensity score matching in a quasi-experimental design to mimic a randomized, controlled trial. Propensity score analyses have been both promoted and criticized in the literature, with a known limitation being the impact of unmeasured variables; however, there have been no published randomized trials of targeted temperature management versus no temperature management for patients with initial nonshockable rhythms because of various barriers. Our analysis, which included 519 patients with an initial nonshockable rhythm from the Penn Alliance for Therapeutic Hypothermia (PATH) Registry between 2000 and 2013, was …

The Utility of Therapeutic Hypothermia for Post-Cardiac Arrest Syndrome Patients With an Initial Nonshockable Rhythm.

Therapeutic hypothermia (TH) attenuates reperfusion injury in comatose survivors of cardiac arrest. The utility of TH in patients with nonshockable initial rhythms has not been widely accepted. We sought to determine whether TH improved neurological outcome and survival in postarrest patients with nonshockable rhythms. We identified 519 patients after in- and out-of-hospital cardiac arrest with nonshockable initial rhythms from the Penn Alliance for Therapeutic Hypothermia (PATH) registry between 2000 and 2013. Propensity score matching was used. Patient and arrest characteristics used to estimate the propensity to receive TH were age, sex, location of arrest, witnessed arrest, and duration of arrest. To determine the association between TH and outcomes, we created 2 multivariable logistic models controlling for confounders. Of 201 propensity score-matched pairs, mean age was 63 ± 17 years, 51% were male, and 60% had an initial rhythm of pulseless electric activity. Survival to hospital discharge was greater in patients who received TH (17.6% versus 28.9%; P < 0.01), as was a discharge Cerebral Performance Category of 1 to 2 (13.7% versus 21.4%; P = 0.04). In adjusted analyses, patients who received TH were more likely to survive (odds ratio, 2.8; 95% confidence interval, 1.6-4.7) and to have better neurological outcome (odds ratio, 3.5; 95% confidence interval, 1.8-6.6) than those that did not receive TH. Using propensity score matching, we found that patients with nonshockable initial rhythms treated with TH had better survival and neurological outcome at hospital discharge than those who did not receive TH. Our findings further support the use of TH in patients with initial nonshockable arrest rhythms.

The emergency cardiac arrest response team (eCART): A novel strategy for improving therapeutic hypothermia utilization following out-of-hospital cardiac arrest

BackgroundOut-of hospital cardiac arrest (OHCA) is associated with significant mortality. Therapeutic hypothermia is one of the few interventions that have been shown to increase post-arrest survival as well as enhance neurologic recovery. Despite clinical guidelines recommending the use of therapeutic hypothermia (TH) following cardiac arrest, utilization rates by physicians remain low. We hypothesized that the development of a multi-disciplinary emergency cardiac arrest response team (eCART) would enhance therapeutic hypothermia utilization in the emergency department for OHCA. Methods and resultsAn eCART (emergency department cardiac arrest response team) was created at a single site academic urban emergency department. The eCART team consisted of a physician hypothermia consultant, a cardiologist, a clinical pharmacist, a respiratory therapist and a chaplain. These providers were notified by page prior to the arrival of an OHCA patient and responded to the ED in person or by phone to support the resuscitation. Analysis of pre- and post-intervention data demonstrated a significant increase in the rate of TH utilization (64% to 96%). There was a non-significant decrease in the time to target temperature. ConclusionsThe creation of a coordinated, multi-disciplinary care team, providing real-time support for OHCA patients increased TH utilization in an emergency department.

Therapeutic hypothermia in cerebral air embolism: a case report

BackgroundCerebral air embolism is a life-threatening complication of various diagnostic and therapeutic procedures. Hyperbaric oxygenation is considered to be the cornerstone of its treatment.Case descriptionWe report a patient with cerebral air embolism after endoscopy of a perineal abscess. Immediate CT imaging confirmed the diagnosis and MRI showed cortically localized areas of restricted diffusion along the gyri. Since hyperbaric oxygenation was not available, moderate hypothermia was applied for neuroprotection.ConclusionThis case illustrates a rare complication of endoscopic interventions, and imaging characteristics of cerebral air embolism were described. Furthermore, we discuss the potential utility of therapeutic hypothermia in cerebral air embolism.

Clinical examination for prognostication in comatose cardiac arrest patients

ObjectiveTo build new algorithms for prognostication of comatose cardiac arrest patients using clinical examination, and investigate whether therapeutic hypothermia influences the value of the clinical examination. MethodsFrom 2000 to 2007, 500 consecutive patients in non-traumatic coma were prospectively enrolled, 200 of whom were post-cardiac arrest. Outcome was determined by modified Rankin Scale (mRS) score at 6 months, with mRS≤3 indicating good outcome. The clinical examination was performed on days 0, 1, 3 and 7 post-arrest, and clinical variables analyzed for importance in prognostication of outcome. A classification and regression tree analysis (CART) was used to develop a predictive algorithm. ResultsGood outcome was achieved in 9.9% of patients. In CART analysis, motor response was often chosen as a root node, and spontaneous eye movements, pupillary reflexes, eye opening and corneal reflexes were often chosen as splitting nodes. Over 8% of patients with absent or extensor motor response on day 3 achieved a good outcome, as did 2 patients with myoclonic status epilepticus. The odds of achieving a good outcome were lower in patients who suffered asystole (OR 0.187, 95% CI: 0.039–0.875, p=0.033) compared with ventricular fibrillation or non-perfusing ventricular tachycardia, but some still achieved good outcome. The absence of pupillary and corneal reflexes on day 3 remained highly reliable for predicting poor outcome, regardless of therapeutic hypothermia utilization. ConclusionThe clinical examination remains central to prognostication in comatose cardiac arrest patients in the modern area. Future studies should incorporate the clinical examination along with modern technology for accurate prognostication.

Abstract 222: Does Gender Matter for Postarrest Care?

Introduction: Studies have shown that after cardiac arrest women have lower survival to discharge rates than men. These differences are surprising, considering that women are more often successfully resuscitated in the prehospital setting. Differences in survival to discharge rates might be partially attributed to disparity in post arrest care, similar to what is seen in myocardial infarction (MI). Hypothesis: There is gender disparity in the provision of targeted post arrest care interventions. Methods: This prospective study explores gender disparity in a prospective Canadian data set of non-traumatic, EMS treated, out of hospital cardiac arrest (OHCA) patients presenting to hospitals in the Strategies for Post Arrest Care (SPARC) network between March 16, 2010 and March 31, 2012. All patients with sustained return of spontaneous circulation (palpable pulse for &gt;20 mins) were included in the analysis. Unadjusted chi square tests and logistic regression models were employed to examine the relationship between gender, and provision of post arrest care interventions (coronary angiography, percutaneous coronary intervention (PCI), therapeutic hypothermia, electrical physiology consultation and internal cardiac defibrillator (ICD) placement and two or more neuroprognostic testing ≥ 72 hours). Results: From a total of 2,199 OHCA patients (1,447 men, 752 women), 992 had sustained return of spontaneous circulation (36.6% women, mean age 68.2 years; 63.4% men, mean age 63.9). There were gender differences in utilization of coronary angiography (12.1% in women vs. 20.8% in men, adjusted OR 0.53, 95% CI 0.36 to 0.77, p=0.013) and PCI (3.7% in women vs. 5.8% in men, adjusted OR 0.63, 95% CI 0.41 to 0.98, p=0.042). ICD was less utilized in women, but differences were not significantly different (4.9% in women vs. 8.1% in men, adjusted OR 0.59, 95% CI 0.33 to 1.02 p=0.062). There were no gender differences in utilization of therapeutic hypothermia and neuroprognostic testing ≥ 72 hours. Conclusion: The observed gender differences in utilization of coronary angiography and PCI intervention may be due to disparity in care and/or differences in underlying pathophysiology of cardiac arrest between men and women contributing to women’s unfavorable outcomes.

Abstract 34: National Trends in Therapeutic Hypothermia, Mortality and Resource Utilization After Cardiac Arrest

Background: In 2002, the Advanced Life Support Task Force of the International Liaison Committee on Resuscitation recommended the use of hypothermia in unconscious adult patients with out-of-hospital cardiac arrest. Since then, various retrospective and prospective studies have shown to improve outcomes with therapeutic hypothermia in select cases of cardiac arrest. Despite the evidence of benefit, it is a widely underutilized in US hospitals. We aimed to study 5-year trend in the use of therapeutic hypothermia in the US hospitals. We also studied trends in the outcome and resource utilization in cardiac arrest over the study period. Methods: We analyzed data for years 2005-2009 from the United States Nationwide Inpatient Sample which is a 20% stratified clustered sample of all non-federal hospital discharges. Using International Classification of Diseases-9 (ICD-9) codes, we identified cases with cardiac arrest (427.5) who underwent therapeutic hypothermia (99.81). Population estimates were obtained by complex sample analysis used for NIS design. Comparisons were made by using χ2 and student-t tests. Trend analysis was performed by univariate regression using the year as a predictor variable. Results: We included a total of 687211 cases of cardiac arrest, of which 3420 (0.498%) underwent therapeutic hypothermia. Patients with therapeutic hypothermia were less likely of female gender (36.7% vs. 45.6%, p&lt;0.001) and were more likely to be younger (mean age: 59.9 vs. 65.8 years, p&lt;0.001). Compared to White (0.59%), African-American (0.34%) and Hispanic (0.25%) patients had lower use of hypothermia (p&lt;0.001). Patient who underwent hypothermia incurred higher inflation adjusted hospital charges (117119 vs. 90511 USD, p&lt;0.001). The discharge survival rate was also higher in patients with hypothermia treatment (41.8% vs. 37.2%, p=0.015). There was a significant upward trend in utilization of therapeutic hypothermia and downward trend in inpatient mortality during the 5-year study period (figure). Conclusions: With accumulating evidence of benefits of therapeutic hypothermia after cardiac arrest, its utilization rate in US has gradually improved over last few years. Though this finding is encouraging, a substantial proportion of eligible patients do not receive this treatment. Downward trend of post-arrest mortality found in this study may be an indicator of improvements in advanced life support protocols over the years.

Therapeutic Hypothermia After Cardiac Arrest is Underutilized in the United States

Little is known about the frequency of therapeutic hypothermia use after cardiac arrest in the United States. We, therefore, analyzed the Nationwide Inpatient Sample (NIS) to determine the prevalence of hypothermia use after cardiac arrest and patient and hospital factors associated with its use. Using 2007 NIS data, we identified adult patients with cardiac arrest using the ICD-9 diagnosis code, 427.5, while the use of therapeutic hypothermia was based on the ICD-9 procedure code, 99.81. Among 26,519 adult patients with cardiac arrest, only 92 (0.35%) were coded as having received therapeutic hypothermia. In a multivariable logistic regression model, independent factors associated with the use of therapeutic hypothermia included age as a continuous variable ([odds ratios] OR 0.97, 95% CI 0.963-0.989, p<0.001), comorbidity adjusted mortality score (OR 1.06, 95% CI 1.04-1.08, p<0.001), admission from the emergency room (OR 2.17, 95% CI 1.191-3.949, p=0.011), teaching hospital status (OR 2.68, 95% CI 1.36-5.29, p=0.005), acute myocardial infarction (OR 1.96, 95% CI 1.14-3.36, p=0.015), hospital location in the western United States (OR 2.21, 95% CI 1.16-3.14, p=0.011), and >97% registered nurse hospital staffing (OR 2.64, 95% CI 1.62-4.30, p<0.001). Therapeutic hypothermia may be utilized in <1% of cardiac arrest patients in U.S. hospitals. We identified important patient and hospital factors associated with therapeutic hypothermia utilization. Efforts to increase generalized utilization of this effective resuscitation strategy are warranted.

Abstract 260: The Changing Pattern of Utilization of Therapeutic Hypothermia Post Cardiac Arrest: A Single-Center Experience

Background: In 2005, the AHA/ILCOR Guidelines recommended hypothermia as a class I therapy post VF/VT arrest. The benefit of this therapy in patients with non-VF rhythms remains disputed. Hence, the 2010 AHA guidelines encourage but do not list hypothermia as a class 1 therapy in patients with a non-VF rhythm. We evaluated the changing patterns of utilization of therapeutic hypothermia from 2004-2010. Methods: In 123 survivors of non-traumatic out-of-hospital cardiac arrest, data were collected utilizing the Utstein guidelines. Outcomes were examined for 3 time periods: all patients from 2004-2005, 2006-2007, and 2008-2010. Data are presented as mean ± SD, median and 25th, 75th percentiles, or as percentages for dichotomous variables. Analysis was by ANOVA. Results: There was no substantial change in the clinical profile of the patients resuscitated from 2004-2010. The use of hypothermia increased in VF/VT survivors to near 90% in 2010. However, the use of hypothermia in non-VF rhythm patients also increased from 21 % to 65.7 % (p&lt;0.01) with no improvement in survival or neurological status (all p ns). Conclusion: Over 6 years the use of hypothermia for VF/VT patients has increased. However, with no data of proven benefit, the use of hypothermia in patients with non-VF rhythms has tripled. The appropriateness of such aggressive therapy in Non-VF/VT patients warrants reconsideration.

Therapeutic hypothermia for acute ischemic stroke

Intravenous recombinant tissue plasminogen activator remains the only US FDA-approved treatment for acute ischemic stroke. However, the very limited time window for its administration restricts its usefulness. Furthermore, it is becoming increasingly clear that, given the numerous pathways via which cerebral ischemia causes cell death, the capacity to inhibit multiple mechanisms simultaneously may provide additive or synergistic beneficial clinical effects for stroke patients. Although no clinical trials have yet investigated the efficacy of therapeutic hypothermia in focal cerebral ischemia, its pleiotropic neuroprotective actions, positive results in preclinical studies, as well as proven enhancement of neurologic outcomes in survivors of cardiac arrest and newborns with hypoxic-ischemic encephalopathy, make this neuroprotective strategy highly promising. This review presents an overview of the potential role of hypothermia in the treatment of acute ischemic stroke and discusses ischemic cell death pathophysiology, neuroprotective mechanisms of hypothermia, methodologies employed for the induction of hypothermia, results from animal models of cerebral ischemia, and finally, currently available clinical trial data. Two valuable lessons learned thus far are that first, rapid induction of hypothermia is key and is best accomplished with a combination of ice-cold saline infusion and the use of endovascular cooling devices, and second, that shivering can be overcome with aggressive anti-shivering protocols including meperidine, buspirone and surface warming. We await the results of clinical trials to determine the utility of therapeutic hypothermia in acute ischemic stroke. If proven efficacious, hypothermia would be a welcome complement to established reperfusion therapies for ischemic stroke patients.