Therapeutic hypothermia after cardiac arrest

PURPOSE OF REVIEW: Patients who are successfully resuscitated following cardiac arrest often have a significant medical condition termed postresuscitation disease. This includes myocardial stunning, metabolic abnormalities and neurologic injury from global ischemia. There are no clinical signs or diagnostic tests for 24-72 h to distinguish patients who will and will not recover neurologic function. RECENT FINDINGS: Therapeutic hypothermia had been advocated for decades as a treatment to improve neurologic outcome after cardiac arrest. The early studies focused on moderate hypothermia, which was associated with complications and was not clearly beneficial. Over the past decade, studies have focused on mild hypothermia with target temperatures of 32-34 degrees C. Two recent multicentered, randomized, controlled trials have demonstrated improved neurologic outcome with mild therapeutic hypothermia applied to comatose survivors after cardiac arrest compared with a normothermic control group. SUMMARY: As a result of these studies the International Liaison Committee on Resuscitation recommends that 'Unconscious adult patients with spontaneous circulation after out-of-hospital cardiac arrest should be cooled to 32 degrees C to 34 degrees C for 12 to 24 hours when the initial rhythm was ventricular fibrillation'. Mild therapeutic hypothermia should also be considered for patients with in-hospital arrest and asystole and pulseless electrical activity who are comatose after return of spontaneous circulation.     

Therapeutic hypothermia for a comatose survivor of near-hanging

Therapeutic hypothermia is recommended for comatose survivors of cardiac arrest. Therapeutic hypothermia ameliorates multiple pathophysiologic mechanisms involved in ischemia-reperfusion injury, which may occur after cardiac arrest and near-hanging. Therapeutic hypothermia has not been prospectively studied in near-hanging. Victims of near-hanging suffer from strangulation with cerebral ischemia and resultant reperfusion injury rather than a fatal cervical spine injury. We report a case where therapeutic hypothermia was applied to a comatose survivor of near-hanging. A 41-year-old man presented with coma following attempted suicide by hanging. The patient underwent 24 hours of mild therapeutic hypothermia. The patient was discharged without neurologic sequelae and a Modified Rankin Scale of 0 (back to his baseline status). We present a case where therapeutic hypothermia was used safely and successfully in a patient without cardiac arrest but still in coma after attempted suicide by hanging. No randomized controlled trials on therapeutic hypothermia for comatose survivors of near-hanging victims have been published. However, in the absence of better evidence, it seems reasonable to consider hypothermia treatment in comatose near-hanging victims until more evidence can be obtained.     

Therapeutic hypothermia for comatose survivors after near-hanging—A retrospective analysis

Background

Patients who survive after suicidal hanging attempts suffer from transient brain ischaemia. Morbidity and mortality is high, and no specific therapy is available. Hypothermia attenuates ischaemic brain damage and has become standard care in comatose survivors of cardiac arrest; therapeutic hypothermia may thus be useful for near-hanging victims as well.

Objectives

To perform a literature review on outcome and outcome predictors after near-hanging. To make a retrospective chart review on treatment and outcome of near-hanging victims in two Swedish intensive care units during a 4-year period (2003–2006).

Methods

The literature review was conducted as a Medline search. Study patients were identified and data retrieved from the intensive care units’ medical records. The primary outcome measure was neurological function at discharge.

Results

No randomised, controlled trials were found in the Medline search. Thirteen patients could be identified and were included in the study, all were in coma and three had suffered cardiac arrest. Outcome was good in six of eight patients treated with hypothermia, as compared to three of five patients who were not. All three patients with cardiac arrest received hypothermia treatment and outcome was good in one.

Conclusion

No randomised, controlled trial for treatment of near-hanging victims has been published. No conclusions could be drawn regarding treatment effects of hypothermia in this survey, but in the absence of better evidence, it seems reasonable to consider hypothermia treatment in all comatose near-hanging victims.     

From evidence to clinical practice: effective implementation of therapeutic hypothermia to improve patient outcome after cardiac arrest

OBJECTIVES: Therapeutic hypothermia has been recommended for postcardiac arrest coma due to ventricular fibrillation. However, no studies have evaluated whether therapeutic hypothermia could be effectively implemented in intensive care practice and whether it would improve the outcome of all comatose patients with cardiac arrest, including those with shock or with cardiac arrest due to nonventricular fibrillation rhythms. DESIGN: Retrospective study. SETTING: Fourteen-bed medical intensive care unit in a university hospital. PATIENTS: Patients were 109 comatose patients with out-of-hospital cardiac arrest due to ventricular fibrillation and nonventricular fibrillation rhythms (asystole/pulseless electrical activity). INTERVENTIONS: We analyzed 55 consecutive patients (June 2002 to December 2004) treated with therapeutic hypothermia (to a central target temperature of 33 degrees C, using external cooling). Fifty-four consecutive patients (June 1999 to May 2002) treated with standard resuscitation served as controls. Efficacy, safety, and outcome at hospital discharge were assessed. Good outcome was defined as Glasgow-Pittsburgh Cerebral Performance category 1 or 2. MEASUREMENTS AND MAIN RESULTS: In patients treated with therapeutic hypothermia, the median time to reach the target temperature was 5 hrs, with a progressive reduction over the 18 months of data collection. Therapeutic hypothermia had a major positive impact on the outcome of patients with cardiac arrest due to ventricular fibrillation (good outcome in 24 of 43 patients [55.8%] of the therapeutic hypothermia group vs. 11 of 43 patients [25.6%] of the standard resuscitation group, p = .004). The benefit of therapeutic hypothermia was also maintained in patients with shock (good outcome in five of 17 patients of the therapeutic hypothermia group vs. zero of 14 of the standard resuscitation group, p = .027). The outcome after cardiac arrest due to nonventricular fibrillation rhythms was poor and did not differ significantly between the two groups. Therapeutic hypothermia was of particular benefit in patients with short duration of cardiac arrest (<30 mins). CONCLUSIONS: Therapeutic hypothermia for the treatment of postcardiac arrest coma can be successfully implemented in intensive care practice with a major benefit on patient outcome, which appeared to be related to the type and the duration of initial cardiac arrest and seemed maintained in patients with shock.     

History of diabetes mellitus as a neurologic predictor in comatose survivors of cardiac arrest of cardiac origin treated with mild hypothermia

AimTo investigate the impact of a history of diabetes mellitus on the neurologic outcome in comatose survivors of cardiac arrest of cardiac origin treated with mild hypothermia.MethodsA prospective observational study was performed between September 2003 and July 2008. Eighty comatose survivors of cardiac arrest of cardiac origin were treated with mild hypothermia. Neurologic outcome at the time of hospital discharge, 30-day survival, and complications were assessed.ResultsTwenty-four of the 80 patients (30%) had a history of diabetes. The rate of favorable neurologic outcome was significantly lower in diabetic (17%) than in nondiabetic patients (46%) (p = 0.01). The rate of 30-day survival was lower in diabetic (33%) than in nondiabetic patients (54%), but the difference was not significant (p = 0.10). Multivariate analysis suggested that a history of diabetes was an independent predictor of unfavorable neurologic outcome (odds ratio 7.00, 95% confidence interval 1.42–46.19, p = 0.03), but not for 30-day survival. There was no significant difference in the prevalence of complications.ConclusionA history of diabetes is associated with poor neurologic outcome in comatose survivors of cardiac arrest treated with mild hypothermia.     

Mild therapeutic hypothermia shortens intensive care unit stay of survivors after out-of-hospital cardiac arrest compared to historical controls

Introduction

Persistent coma is a common finding after cardiac arrest and has profound ethical and economic implications. Evidence suggests that therapeutic hypothermia improves neurological outcome in these patients. In this analysis, we investigate whether therapeutic hypothermia influences the length of intensive care unit (ICU) stay and ventilator time in patients surviving out-of-hospital cardiac arrest.

Methods

A prospective observational study with historical controls was conducted at our medical ICU. Fifty-two consecutive patients (median age 62.6 years, 43 males, 34 ventricular fibrillation) submitted to therapeutic hypothermia after out-of-hospital cardiac arrest were included. They were compared with a historical cohort (n = 74, median age 63.8 years, 53 males, 43 ventricular fibrillation) treated in the era prior to hypothermia treatment. All patients received the same standard of care. Neurological outcome was assessed using the Pittsburgh cerebral performance category (CPC) score. Univariate analyses and multiple regression models were used.

Results

In survivors, therapeutic hypothermia and baseline disease severity (Acute Physiology and Chronic Health Evaluation II [APACHE II] score) were both found to significantly influence ICU stay and ventilator time (all P < 0.01). ICU stay was shorter in survivors receiving therapeutic hypothermia (median 14 days [interquartile range (IQR) 8 to 26] versus 21 days [IQR 15 to 30] in the control group; P = 0.017). ICU length of stay and time on ventilator were prolonged in patients with CPC 3 or 4 compared with patients with CPC 1 or 2 (P = 0.003 and P = 0.034, respectively). Kaplan-Meier analysis showed improved probability for 1-year survival in the hypothermia group compared with the controls (log-rank test P = 0.013).

Conclusion

Therapeutic hypothermia was found to significantly shorten ICU stay and time of mechanical ventilation in survivors after out-of-hospital cardiac arrest. Moreover, profound improvements in both neurological outcome and 1-year survival were observed.     

Neurologic recovery after therapeutic hypothermia in patients with post-cardiac arrest myoclonus

Early myoclonus in comatose survivors of cardiac arrest, even when it is not myoclonic status epilepticus (MSE), is considered a sign of severe global brain ischemia and has been associated with high rates of mortality and poor neurologic outcomes. We report on three survivors of primary circulatory cardiac arrests who had good neurologic outcomes (two patients with a CPC score = 1 and one patient with a CPC score = 2) after mild therapeutic hypothermia, despite exhibiting massive myoclonus within the first 4 h after return of spontaneous circulation. The concept that early myoclonus heralds a uniformly poor prognosis may need to be reconsidered in the era of post-cardiac arrest mild therapeutic hypothermia.     

The pituitary-adrenal axis is activated more in non-survivors than in survivors of cardiac arrest, irrespective of therapeutic hypothermia

OBJECTIVE: To investigate the effect of therapeutic hypothermia in the prognostic value of the pituitary-adrenal axis in comatose patients after cardiac arrest. DESIGN: Prospective observational study in intensive care units (ICU) of a university and an affiliated regional hospital. PATIENTS: Twenty-nine consecutive patients, in coma after cardiac arrest, admitted to the ICU and treated by hypothermia. MEASUREMENTS: On ICU-admission (T=1), at reaching the target of 32-33 degrees C during therapeutic hypothermia (T=2), at the end of hypothermia (T=3) and 48h later (T=4), plasma adrenocorticotrophic hormone (ACTH), serum cortisol, albumin and corticosteroid-binding globulin (CBG) were measured. A short 250mug ACTH test was performed at each time-point, except at T=1. The free cortisol index (FCI) and free cortisol calculated by Coolens method were also evaluated. RESULTS: The ICU mortality was 59%, including withdrawal of life-sustaining treatment in 45% because of negative somatosensory evoked potentials. ACTH and (free) cortisol levels (mean 13.1pmol/L vs. 6.0pmol/L and 1250nmol/L vs. 596nmol/L, respectively) were higher in non-survivors than in survivors. Levels decreased in time, but the relative difference between outcome groups was maintained until T=4. The cortisol response to ACTH was lower in non-survivors at T=3 (P=0.047) only. CONCLUSIONS: In comatose patients resuscitated from cardiac arrest, the pituitary-adrenal axis is activated particularly in those dying in the ICU, irrespective of therapeutic hypothermia. Hence, activation of the axis may be a marker of fatal cerebral damage. There is no firm evidence for relative adrenal insufficiency associated with death and a transiently blunted cortisol response to ACTH in non-survivors may be attributed to higher baseline values.     

Prognostic factors associated with hospital survival in comatose survivors of cardiac arrest

AIM: To identify patient, cardiac arrest and management factors associated with hospital survival in comatose survivors of cardiac arrest.METHODS: A retrospective, single centre study of comatose patients admitted to our intensive care unit (ICU) following cardiac arrest during the twenty year period between 1993 and 2012. This study was deemed by the Human Research Ethics Committee (HREC) of Monash Health to be a quality assurance exercise, and thus did not require submission to the Monash Health HREC (Research Project Application, No. 13290Q). The study population included all patients admitted to our ICU between 1993 and 2012, with a discharge diagnosis including “cardiac arrest”. Patients were excluded if they did not have a cardiac arrest prior to ICU admission (i.e., if their primary arrest was during their admission to ICU), or were not comatose on arrival to ICU. Our primary outcome measure was survival to hospital discharge. Secondary outcome measures were ICU and hospital length of stay (LOS), and factors associated with survival to hospital discharge.RESULTS: Five hundred and eighty-two comatose patients were admitted to our ICU following cardiac arrest, with 35% surviving to hospital discharge. The median ICU and hospital LOS was 3 and 5 d respectively. There was no survival difference between in-hospital and out-of-hospital cardiac arrests. Males made up 62% of our cardiac arrest population, were more likely to have a shockable rhythm (56% vs 37%, P < 0.001), and were more likely to survive to hospital discharge (40% vs 28%, P = 0.006). On univariate analysis, therapeutic hypothermia, regardless of method used (e.g., rapid infusion of ice cold fluids, topical ice, “Arctic Sun”, passive rewarming, “Bair Hugger”) and location initiated (e.g., pre-hospital, emergency department, intensive care) was associated with increased survival. There was however no difference in survival associated with target temperature, time at target temperature, location of initial cooling, method of initiating cooling, method of maintaining cooling or method of rewarming. Patients that survived were more likely to have a shockable rhythm (P < 0.001), shorter time to return of spontaneous circulation (P < 0.001), receive therapeutic hypothermia (P = 0.03), be of male gender (P = 0.006) and have a lower APACHE II score (P < 0.001). After multivariate analysis, only a shockable initial rhythm (OR = 6.4, 95%CI: 3.95-10.4; P < 0.01) and a shorter time to return of spontaneous circulation (OR = 0.95, 95%CI: 0.93-0.97; P < 0.01) was found to be independently associated with survival to hospital discharge.CONCLUSION: In comatose survivors of cardiac arrest, shockable rhythm and shorter time to return of spontaneous circulation were independently associated with increased survival to hospital discharge.     

Induced hypothermia using large volume,ice-cold intravenous fluid in comatose survivors of out-of-hospital cardiac arrest: a preliminary report

STUDY HYPOTHESIS: Recent studies have shown that induced hypothermia for twelve to twenty four hours improves outcome in patients who are resuscitated from out-of-hospital cardiac arrest. These studies used surface cooling, but this technique provided for relatively slow decreases in core temperature. Results from animal models suggest that further improvements in outcome may be possible if hypothermia is induced earlier after resuscitation from cardiac arrest. We hypothesized that a rapid infusion of large volume (30 ml/kg), ice-cold (4 degrees C) intravenous fluid would be a safe, rapid and inexpensive technique to induce mild hypothermia in comatose survivors of out-of-hospital cardiac arrest. METHODS: We enrolled 22 patients who were comatose following resuscitation from out-of-hospital cardiac arrest. After initial evaluation in the Emergency Department (ED), a large volume (30 ml/kg) of ice-cold (4 degrees C) lactated Ringers solution was infused intravenously over 30 min. Data on vital signs, arterial blood gas, electrolyte and hematological was collected immediately before and after the infusion. RESULTS: The rapid infusion of large volume, ice-cold crystalloid fluid resulted in a significant decrease in median core temperature from 35.5 to 33.8 degrees C. There were also significant improvements in mean arterial blood pressure, renal function and acid-base analysis. No patient developed pulmonary odema. CONCLUSION: A rapid infusion of large volume, ice-cold crystalloid fluid is an inexpensive and effective method of inducing mild hypothermia in comatose survivors of out-of-hospital cardiac arrest, and is associated with beneficial haemodynamic, renal and acid-base effects. Further studies of this technique are warranted.     

Clinically induced hypothermia: why chill your patient?

Clinically induced hypothermia is an evidence-based intervention strategy that can improve the neurological outcome of unconscious patients after sudden cardiac arrest. Until recently, clinically induced hypothermia has been primarily used during surgery as a mechanism of preserving cardiovascular and neurologic stability of patients. Current evidence suggests that early use of mild hypothermia therapy in select populations of patients improves survival and neurologic outcome postdischarge. While clinically induced hypothermia is beneficial as a treatment to preserve neurologic function, it is not without complications. The purpose of this article is to review current literature and evidence-based nursing practice implications for managing the induction of a hypothermic state in adult patients who remain comatose after initial resuscitation from sudden cardiac arrest. Physiologic benefits of hypothermia, complications, and nursing care considerations will be presented.     

Amplitude-integrated EEG (aEEG) predicts outcome after cardiac arrest and induced hypothermia

Objective To evaluate the use of continuous amplitude-integrated EEG (aEEG) as a prognostic tool for survival and neurological outcome in cardiac arrest patients treated with hypothermia.Design Prospective, observational study.Setting Multidisciplinary intensive care unit in a university hospital.Intervention Comatose survivors of cardiac arrest were treated with induced hypothermia for 24 h. An aEEG recording was initiated upon arrival at the ICU and continued until the patient regained consciousness or, if the patient remained in coma, no longer than 120 h. The aEEG recording was not available to the ICU physician, and the aEEG tracings were interpreted by a neurophysiologist with no knowledge of the patient's clinical status. Only clinically visible seizures were treated. Measurements and results Thirty-four consecutive hypothermia-treated cardiac arrest survivors were included. At normothermia (mean 37 h after cardiac arrest), the aEEG pattern was discriminative for outcome. All 20 patients with a continuous aEEG at this time regained consciousness, whereas 14 patients with pathological aEEG patterns (flat, suppression-burst or status epilepticus) did not regain consciousness and died in hospital. Patients were evaluated neurologically upon discharge from the ICU and after 6 months, using the Cerebral Performance Category (CPC) scale. Eighteen patients were alive with a good cerebral outcome (CPC 1--2) at 6-month follow-up. Conclusion A continuous aEEG pattern at the time of normothermia was discriminative for regaining consciousness. aEEG is an easily applied method in the ICU setting.     

Bispectral index (BIS) helps predicting bad neurological outcome in comatose survivors after cardiac arrest and induced therapeutic hypothermia

Aim of the studyDetermine the use of bispectral index (BIS) as prognostic tool in therapeutic hypothermia (TH) treated comatose survivors after cardiac arrest (CA), regardless of initial rhythm, location or cause.MethodsProspective, single-centre, unblinded, observational cohort study in an 18 bed general ICU in a tertiary teaching hospital. 45 consecutive comatose patients admitted after CA and treated with TH were included. All patients were sedated with a standardised protocol including neuromuscular blockade. Induced TH was started as soon as possible after arrival in the hospital and continued for 24 h before slow rewarming. Sedation was stopped after reaching normothermia (36 °C). All patients benefited from maximal supportive intensive care and no therapeutic withdrawal or withholding was done unless bad neurological status was confirmed. Continuous BIS monitoring was performed over 72 h in all patients.Results14 patients presented BIS values of zero (0) during their ICU stay. At 6 months 11 patients were dead, 1 remained comatose and 2 had severe neurological sequelae (CPC3). No patient of this group had good neurological outcome or improved his neurological outcome between ICU and 6-month follow-up. 31 patients had BIS values higher than 0. At 6 months of those, 11 died, none remained comatose, 3 had bad neurological outcome (CPC3) and 17 had no or minor neurological sequelae (CPC1-2). Thus no correlation between good outcome and BIS values higher than 0 is possible.ConclusionsBIS values of 0 help predict bad neurological outcome after CA and induced hypothermia.     

Somatosensory and brainstem auditory evoked potentials in cardiac arrest patients treated with hypothermia

OBJECTIVE: To evaluate the prognostic value of short-latency median nerve somatosensory evoked potentials and brainstem auditory evoked potentials in outcome prediction for comatose cardiac arrest patients treated with hypothermia. DESIGN: Prospective, randomized, controlled trial of mild hypothermia after out-of-hospital cardiac arrest; a substudy of the European Hypothermia After Cardiac Arrest study. SETTING: Intensive care unit of a tertiary referral hospital (Helsinki University Central Hospital). PATIENTS: Sixty consecutive patients (aged 18-75 yrs) resuscitated from out-of-hospital ventricular fibrillation and comatose at 24 hrs after cardiac arrest; all patients were randomly assigned either to therapeutic hypothermia of 33 degrees C or normothermia. INTERVENTIONS: All patients received standard intensive care for at least 2 days. Patients randomized to hypothermia were cooled with an external cooling device for 24 hrs and then allowed to rewarm slowly for 12 hrs. In the normothermia group, the core temperature was kept below 38 degrees C with antipyretics and by physical means. The clinical outcome was assessed 6 months after cardiac arrest. MEASUREMENTS AND MAIN RESULTS: Somatosensory evoked potentials and brainstem auditory evoked potentials were recorded 24-28 hrs after cardiac arrest. All wave latencies were significantly prolonged in the hypothermia group. Bilaterally absent N20 waves predicted permanent coma with a specificity of 100% in both treatment groups. Brainstem auditory evoked potential recordings did not correlate with the outcome in either treatment group. CONCLUSIONS: The prognostic ability of median nerve short-latency somatosensory evoked potentials does not seem to be affected by therapeutic hypothermia. Brainstem auditory evoked potentials had no additional value in outcome prediction.     

Avis de la CE-SRLF sur la démarche de prise de décision de limitation ou d’arrêt des thérapeutiques chez l’adulte en coma postanoxique après un arrêt cardiaque

Since early evaluation of middle to long-term prognosis of patients remaining in coma after resuscitation following cardiac arrest has become a major concern for critical care physicians in terms of patient care as well as for ethical reasons, it appears necessary for the ethics committee (EC) of the Société de réanimation de langue fran?aise (SRLF) to issue recommendations regarding the decision making process to be respected in all deliberations for limitation or discontinuation of life support in patients; the aim is to avoid decisions based only on decision making algorithms such as those recommended by the American Society of Neurology. Additionally, since clinicians must document prognoses of patients remaining in coma after cardiac arrest, the CE-SRLF considers important to underline that there is always some worry and uncertainty in predicting patient??s outcome and that decision to limit or discontinue life support is difficult and cannot merely be based on a recommended flowchart. Due to these concerns, the CE-SRLF recognizes several clearly identified prognostic signs, each associated with a poor neurological outcome in patients remaining comatose after cardiac arrest. Nevertheless, an approach based on the detection of several among these signs should be a priority in order to help clinicians getting an opinion on the most likely outcome of a patient remaining comatose after cardiac arrest, allowing them to inform patient??s family members and friends with sincerity. It should be emphasized that each of such decisions is unique and should always result from a decision-making process among peers and conform to the current SRLF recommendations (2009) on limitation and discontinuation of life support in adult patients in the critical care unit.     

Rôle de l’équipe paramédicale dans la réalisation du contrôle ciblé de la température après un arrêt cardiaque récupéré

Therapeutic hypothermia, also called targeted temperature management, is increasingly used in the intensive care unit (ICU), based on its assessed neuroprotective effects against ischemia-reperfusion-induced brain damage. Targeted temperature management is indicated in comatose adult patients after cardiac arrest if successfully resuscitated from a witnessed out-of-hospital cardiac arrest of presumed cardiac cause with an initial rhythm of ventricular fibrillation or non-perfusing ventricular tachycardia and in a stable hemodynamic condition. Patients after in-hospital cardiac arrest or with other initial rhythms may also benefit. When indicated, therapeutic hypothermia should be quickly performed and tightly controlled. Both surface and core cooling methods target a body temperature of 32 to 34 °C. Thus, it is mandatory to know how to simply manage the routinely available techniques in order to perform hypopthermia as soon as possible, being aware of all side-effects that may alter the expected benefits. Therefore, implementing hypothermia in the ICU involve the whole medical and paramedical staff.     

Impact of urgent coronary angiography on mid-term clinical outcome of comatose out-of-hospital cardiac arrest survivors presenting without ST-segment elevation

BackgroundTiming of coronary angiography (CAG) is still controversial in the out-of-hospital cardiac arrest survivors who present without ST-segment elevation.Methods and resultsWe analysed a prospective registry of 158 comatose survivors of out-of-hospital cardiac arrest. For further analysis, we included 99 patients without ST-segment elevation on the initial electrocardiogram. All patients underwent temperature management. Urgent CAG (<2 h from admission) was performed in 25% of the patients. A definite cause of the cardiac arrest could be identified during the index hospitalization in 82 patients: 36 had a non-ST-segment elevation acute coronary syndrome (NSTE-ACS) and 46 had a non-ACS diagnosis. Eighty-seven patients (88%) survived the index hospitalization and 65 (66%) were alive at six months. A favourable neurological status (cerebral performance category ≤2) was observed in 56% of the patients at discharge and in 56% after six months of follow-up. Neither the survival nor the neurological outcome differed between the patients in whom the CAG was performed urgently upon the admission and the patients in whom the CAG was initially not performed, regardless of the aetiology of the cardiac arrest. On the other hand, performing an urgent CAG was safe and it did not prolong the average time to achieve an effective hypothermia.ConclusionsPerforming an urgent CAG in comatose cardiac arrest survivors without ST-segment elevation was not associated with better clinical and neurological outcome as compared to the initially conservative approach.     

Prognostic values of gray matter to white matter ratios on early brain computed tomography in adult comatose patients after out-of-hospital cardiac arrest of cardiac etiology

Aim of the studyPrevious studies found that the gray matter to white matter ratio (GWR) on brain computed tomography (CT) could be used to predict poor outcomes in cardiac arrest survivors. However, these studies have included cardiac arrests of both cardiac and non-cardiac etiologies. We sought to evaluate if the GWR on brain CT can help to predict poor outcomes after out-of-hospital cardiac arrest (OHCA) of cardiac etiology.MethodsUsing a multicenter retrospective registry of adult cardiac arrest survivors treated with therapeutic hypothermia, we identified survivors of OHCA of cardiac etiology who underwent brain CT within 24 h after successful resuscitation. Gray and white matter attenuations were measured, and the GWRs were calculated as in previous studies. The prognostic values of the GWRs were analyzed, and a logistic regression analysis was performed to determine the contribution of the GWR in predicting poor outcomes (Cerebral Performance Category 3–5).Resultsof 283 included patients, 140 had good outcomes and 143 had poor outcomes. Although the GWRs could predict poor outcomes with statistical significance, the sensitivities were remarkably low (3.5% to 5.6%) at cutoff values with 100% specificity. No significant difference in predictive performance was found between the primary predictive model, containing independent poor outcome predictors, and the primary predictive model combined with the GWR.ConclusionIn a cohort of comatose adults after OHCA of cardiac etiology, the GWR demonstrated poor predictive performance and was not helpful in predicting poor outcomes.     

The role of hypothermia in post-cardiac arrest patients with return of spontaneous circulation: a systematic review

ObjectivesTo update a comprehensive systematic review of the use of therapeutic hypothermia after cardiac arrest that was undertaken initially as part of the 2010 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science. The specific question addressed was: ‘in post-cardiac arrest patients with a return of spontaneous circulation, does the induction of mild hypothermia improve morbidity or mortality when compared with usual care?’MethodsPubmed was searched using (“heart arrest” or “cardiopulmonary resuscitation”) AND “hypothermia, induced” using ‘Clinical Queries’ search strategy; EmBASE was searched using (heart arrest) OR (cardiopulmonary resuscitation) AND hypothermia; The Cochrane database of systematic reviews; ECC EndNote Library for “hypothermia” in abstract OR title. Excluded were animal studies, reviews and editorials, surveys of implementation, analytical models, reports of single cases, pre-arrest or during arrest cooling and group where the intervention was not hypothermia alone.Results77 studies met the criteria for further review. Of these, four were meta-analyses (LOE 1); seven were randomised controlled trials (LOE 1), although six of these were from the same set of patients; nine were non-randomised, concurrent controls (LOE 2); 15 were trials with retrospective controls (LOE 3); 40 had no controls (LOE 4); and one was extrapolated from a non-cardiac arrest group (LOE 5).ConclusionThere is evidence supporting the use of mild therapeutic hypothermia to improve neurological outcome in patients who remain comatose following the return of spontaneous circulation after a cardiac arrest; however, much of the evidence is from low-level, observational studies. Of seven randomised controlled trials, six use data from the same patients.     

Early diffusion-weighted imaging and outcome prediction of comatose survivors after suicidal hanging

Purpose

Early outcome prediction after suicidal hanging is challenging in comatose survivors. We analysed the early patterns of brain diffusion-weighted magnetic resonance imaging (DWI) abnormalities in comatose survivors after suicidal hanging.