Michael Holzer

Mild Resuscitative Hypothermia to Improve Neurological Outcome After Cardiac Arrest A Clinical Feasibility Trial

BACKGROUND AND PURPOSEnRecent animal studies showed that mild resuscitative hypothermia improves neurological outcome when applied after cardiac arrest. In a 3-year randomized, prospective, multicenter clinical trial, we hypothesized that mild resuscitative cerebral hypothermia (32 degrees C to 34 degrees C core temperature) would improve neurological outcome after cardiac arrest.nnnMETHODSnWe lowered patients temperature after admission to the emergency department and continued cooling for at least 24 hours after arrest in conjunction with advanced cardiac life support. The cooling technique chosen was external head and total body cooling with a cooling device in conjunction with a blanket and a mattress. Infrared tympanic thermometry was monitored before a central pulmonary artery thermistor probe was inserted.nnnRESULTSnIn 27 patients (age 58 [interquartile range [IQR] 52 to 64] years; 7 women; estimated no-flow duration 6 [IQR 1 to 11] minutes and low-flow duration 15 [IQR 9 to 23] minutes; admitted to the emergency department 36 [IQR 24 to 43] minutes after return of spontaneous circulation), we could initiate cooling within 62 (IQR 41 to 75) minutes and achieve a pulmonary artery temperature of 33+/-1 degrees C 287 (IQR 42 to 401) minutes after cardiac arrest. During 24 hours of mild resuscitative hypothermia, no major complications occurred. Passive rewarming >35 degrees C was accomplished within 7 hours.nnnCONCLUSIONSnMild resuscitative hypothermia in patients is feasible and safe. A clinical multicenter trial might prove that mild hypothermia is a useful method of cerebral resuscitation after global ischemic states.

Time Course of Serum Neuron-Specific Enolase A Predictor of Neurological Outcome in Patients Resuscitated From Cardiac Arrest

BACKGROUND AND PURPOSEnThe prediction of neurological outcome in comatose cardiac arrest survivors has enormous ethical and socioeconomic implications. The purpose of the present study was to investigate the prognostic relevance of the time course of serum neuron-specific enolase (NSE) as a biochemical marker of hypoxic brain damage.nnnMETHODSnSerial analysis of serum NSE levels was performed in 56 patients resuscitated from witnessed, nontraumatic, normothermic, in- or out-of-hospital cardiac arrest. The neurological outcome was evaluated with the use of the cerebral performance category (CPC) within 6 months after restoration of spontaneous circulation (ROSC). The Mann-Whitney U test was used to compare patients with good (CPC 1 to 2) and bad (CPC 3 to 4) neurological outcome. The diagnostic performance at different time points after ROSC was described in terms of areas under receiver operating characteristic curves according to standard methods.nnnRESULTSnPatients with a bad neurological outcome (CPC 3 to 4) had significantly higher NSE levels than those with a good neurological outcome at 12 (P=0.004), 24 (P=0.04), 48 (P<0.001), and 72 hours (P<0.001) after ROSC. The maximum NSE level measured within 72 hours after ROSC was also significantly higher in patients with a bad neurological outcome (P<0.001). The NSE value at 72 hours after ROSC was the best predictor of neurological outcome (area under the curve=0.92+/-0.04). In addition, we also found a significant difference in the time course of NSE concentrations during the first 3 days after ROSC.nnnCONCLUSIONSnSerum NSE levels are valuable adjunctive parameters for assessing neurological outcome after cardiac arrest.

Evaluating arrhythmias in ECG signals using wavelet transforms

Recent work has attempted to utilize wavelet techniques in the analysis of biomedical signals including ECGs. Here, the authors present an energy-based method of interrogating the ECG in VF using high-resolution, log-scale continuous wavelet plots. With this method, underlying structures within the VF waveform are made visible in the wavelet time-scale half space.

Major bleeding complications in cardiopulmonary resuscitation: the place of thrombolytic therapy in cardiac arrest due to massive pulmonary embolism.

OBJECTIVEnThrombolytic therapy in patients with massive pulmonary embolism (MPE) and prolonged cardiopulmonary resuscitation (CPR) is subject to debate. This study was performed to determine whether (1) thrombolytic treatment increases the risk of bleeding complications, (2) if the risk of bleeding is influenced by the duration of CPR and if (3) thrombolytic therapy improves outcome.nnnDESIGNnRetrospective cohort study.nnnSETTINGnEmergency department of a tertiary care university hospital.nnnPATIENTS AND METHODSnSixty-six patients with cardiac arrest (CA) due to MPE admitted between July 1993 and December 2001. Thirty-six patients received thrombolysis (TL) and were compared with 30 patients without thrombolytic therapy. Bleeding complications were assessed by clinical evidence or autopsy.nnnRESULTSnMajor bleeding complications appear to occur more frequently in patients treated with thrombolytics (9/36 (25%) vs. 3/30 (10%)) even though the difference was statistically not significant (P=0.15). It appears that CPR duration >10 min has no adverse impact on major bleeding complications. No difference in the rate of major bleeding complications between thrombolyzed patients who had a CPR duration of </=10 or >10 min could be observed (2/8 (25%) vs. 7/28 (25%), P=0.99). In thrombolyzed patients a return of spontaneous circulation could be achieved more frequently (24/36 (67%) vs.13/30 (43%) in controls, P=0.06) and survival after 24 h was higher (19/36 (53%) vs. 7/30 (23%), P=0.01). Survival to discharge was also higher in the TL group (7/36 (19%) vs. 2/30 (7%)), but not statistically significant (P=0.15).nnnCONCLUSIONnAlthough severe bleeding complications tend to occur more frequently in patients undergoing TL, the benefit of this treatment might outweigh the risk of bleeding.

Time-dependency of sensory evoked potentials in comatose cardiac arrest survivors

Abstract.Objective: To assess the validity of early sensory evoked potential (SEP) recording for reliable outcome prediction in comatose cardiac arrest survivors within 48xa0h after restoration of spontaneous circulation (ROSC). Design and setting: Prospective cohort study in a medical intensive care unit of a university hospital. Patients: Twenty-five comatose, mechanically ventilated patients following cardiopulmonary resuscitation Measurements and results: Median nerve short- and long-latency SEP were recorded 4, 12, 24, and 48xa0h after ROSC. Cortical N20 peak latency and cervicomedullary conduction time decreased (improved) significantly between 4, 12, and 24xa0h after resuscitation in 22 of the enrolled patients. There was no further change in short-latency SEP at 48xa0h. The cortical N70 peak was initially detectable in seven patients. The number of patients with increased N70 peak increased to 11 at 12xa0h and 14 at 24xa0h; there was no further change at 48xa0h. Specificity of the N70 peak latency (critical cutoff 130xa0ms) increased from 0.43 at 4xa0h to 1.0 at 24xa0h after ROSC. Sensitivity decreased from 1.0 at 4xa0h to 0.83 at 24xa0h after ROSC. Conclusion: Within 24xa0h after ROSC there was a significant improvement in SEP. Therefore we recommend allowing a period of at least 24xa0h after cardiopulmonary resuscitation for obtaining a reliable prognosis based on SEP.

Apolipoprotein E Polymorphism: Survival and Neurological Outcome After Cardiopulmonary Resuscitation

Background and Purpose The apolipoprotein E 3/3 (apoE 3/3) genotype is associated with a reduced risk of developing Alzheimer’s disease and with a favorable neurological outcome after traumatic head injury. In vitro studies suggest that the most common genotype, apoE 3/3, may be involved in neuroprotective and neuroregenerative mechanisms. The aim of this study was to determine whether the apoE 3/3 genotype has an impact on survival and neurological outcome after cardiopulmonary resuscitation. Methods Eighty patients with cardiac arrest were investigated prospectively for their apoE genotype. Epidemiological data were assessed according to recommended guidelines. Patients were divided into 2 groups, ie, with the apoE 3/3 genotype present or absent, and tested for differences in survival and neurological outcome. Further statistical analysis with respect to survival and neurological outcome was performed by using a stepwise logistic regression analysis. Results Patients with the apoE 3/3 genotype had a significantly higher survival rate (64% versus 33%, P =0.007) and more often a favorable neurological outcome (55% versus 27%, P =0.013) compared with patients with other apoE genotypes. The apoE 3/3 genotype was shown to be a substantial predictive factor for a favorable neurological outcome (odds ratio 3.2) and was, apart from other essential factors, predictive for survival (odds ratio 4.4) after cardiopulmonary resuscitation. Conclusions These data give evidence that patients with the apoE 3/3 genotype have a better chance of recovery after cardiopulmonary resuscitation than do patients with apoE genotypes other than 3/3.

Thrombolytic therapy after cardiac arrest and its effect on neurological outcome.

OBJECTIVEnthe aim of the study is to investigate the effect of thrombolytic therapy on neurological outcome in patients after cardiac arrest due to acute myocardial infarction. Laboratory investigations have demonstrated that thrombolytic therapy after cardiopulmonary resuscitation improves neurological function.nnnMETHODSnfrom July 1991 to June 1996, patients with witnessed ventricular fibrillation cardiac arrest due to acute MI and successful restoration of spontaneous circulation admitted to the emergency department were analyzed retrospectively. A logistic regression model was used to assess the association between thrombolytic therapy and neurological outcome [best cerebral performance category (CPC) within 6 months after cardiac arrest].nnnRESULTSnall 157 patients [median age 57 years (IQR 50-69)] were analyzed. Thrombolytic therapy was applied in 42 patients (27%). With thrombolytic therapy good functional neurological recovery (CPC 1 or 2) was achieved more frequently (69 vs. 50%, P=0.03). After controlling for age, prehospital dosage of epinephrine, and the duration of cardiac arrest we found a non significant trend towards good neurological recovery when thrombolytic therapy was given (OR 1.9, 95% CI 0.8-4.6).nnnCONCLUSIONnthrombolytic therapy after cardiac arrest due to acute myocardial infarction is associated with improved neurological outcome.

Successful automatic external defibrillator operation by people trained only in basic life support in a simulated cardiac arrest situation

OBJECTIVEnTo show whether in an in-hospital cardiac arrest, early defibrillation can also be performed by hospital staff trained only in basic life support.nnnBACKGROUNDnThe International Liaison Committee on Resuscitation (ILCOR) endorses the concept that in many settings non-medical individuals should be allowed and encouraged to use defibrillators.nnnMETHODSnFive different groups of hospital staff were evaluated whether they were able to correctly operate an automatic external defibrillator in a simulated sudden cardiac arrest situation without any prior instruction. The participants were assigned either to the basic life support-trained group (BLS, n = 40, or to the advanced life support-trained group (ALS, n = 40).nnnRESULTSnAll persons of the only BLS-trained group delivered the three sequential (stacked) shocks with the automatic external defibrillator when persistent ventricular fibrillation was simulated. The ALS-trained persons successfully delivered the three shocks with the automatic external defibrillator in 98% of the cases. When this group used a conventional defibrillator, only 88% were able to deliver the three shocks, however they were able to do it significantly more quickly.nnnCONCLUSIONnUsing an automatic defibrillator without any prior instruction, even persons trained only in BLS were able to deliver three sequential shocks in a simulated persistent ventricular fibrillation cardiac arrest.

Percutaneous cardiopulmonary bypass for therapy resistant cardiac arrest from digoxin overdose

A 79-year 65 kg male called the ambulance service 4 h after ingestion of 100 tablets of digoxin 0.1 mg complaining of nausea and vomiting. The ECG showed an idioventricular escape rhythm with a heart rate of 30/min. After 0.5 mg atropine, heart rate increased to 80/min. Soon after admission to the emergency department, the patient developed electromechanical dissociation. Due to persistent cardiac arrest, percutaneous cardiopulmonary bypass was started, and the ECG rhythm changed to ventricular fibrillation. Several attempts to terminate ventricular fibrillation by electrical defibrillation failed. Fifty-eight minutes after cardiac arrest, antidigoxin-Fab was administered and 1 h 25 min after cardiac arrest, ventricular fibrillation was terminated by the tenth electrical defibrillation attempt. Initially, the patients overall status improved over the next 2 days, but then he developed a severe adult respiratory distress syndrome and died of unresponsive septic shock 12 days after ingestion of digoxin. This case demonstrates that percutaneous cardiopulmonary bypass may provide support in patients with cardiac arrest due to massive digoxin overdose. This temporary support can maintain adequate tissue perfusion during the time required for drug neutralization in order to achieve successful defibrillation. Percutaneous cardiopulmonary bypass should be considered in patients with severe, but temporary cardiac dysfunction due to a life-threatening drug overdose.

Effect of cooling after human cardiac arrest on myocardial infarct size

AIMSnThe Hypothermia after Cardiac Arrest (HACA) trial assessed whether mild therapeutic hypothermia improved the rate of good neurological recovery in patients after ventricular fibrillation cardiac arrest of presumed cardiac origin. We evaluated the impact of hypothermia on myocardial injury.nnnMETHODSnRe-analysis of a HACA trial subset for our department (cooling, n=55; controls, n=56). Plasma levels of CK, CKMB and ST-scores were used as a measure of infarct size.nnnRESULTSnArea under the curve (AUC) for CK was 28,786U/l x 24 h (IQR 5646-44,998) in the cooling group and 20,373U/l x 24 h (IQR 8211-30,801) for controls (p=0.40), for CKMB AUC was 1691U/l x 24 h (IQR 724-3330) and 1187U/l x 24 h (IQR 490-2469), respectively (p=0.18). The ST score was -40% (IQR [-55]-[+16]) in the cooling group (n=23) and -22% (IQR [-84]-[+33]) for controls (n=24) (p=0.76). When the cooling group was stratified into early (< or =8h) and longer (>8h) time to target temperature, the early group displayed a significantly lower CK 7340U/l x 24 h (IQR 3921-33,753) vs. 38,986U/l x 24 h (IQR 23,945-57,514, p=0.007) and a lower CKMB.nnnCONCLUSIONnCooling after successful resuscitation for ventricular fibrillation cardiac arrest did not influence infarct size. Cautious interpretation of the subgroup analysis may indicate a favourable trend for early cooling.