Peter Stratil

Causes of in-hospital cardiac arrest and influence on outcome.

AIM OF THE STUDY To evaluate the relationship between cause and outcome of in-hospital cardiac arrest. METHODS Retrospective analysis of resuscitation data, causes of cardiac arrest and outcome with a follow-up to 6 months of a cardiac arrest registry in an emergency department of a tertiary care hospital, covering a 17.5-year period. RESULTS Of 1041 patients, 653 were male (63%), the median age was 64 years (IQR 53-73), 51% suffered cardiac arrest in the emergency department. The first recorded rhythm showed PEA in 432 (41%), ventricular fibrillation in 404 (39%) and asystole in 205 (20%) patients. Cardiac arrest of cardiac origin occurred in 63% of all patients, with 35% of them due to acute myocardial infarction. Non-cardiac causes were mostly due to pulmonary causes (15% of all patients). Aortic dissection/rupture, exsanguination, intoxication and adverse drug reactions, metabolic, cerebral, sepsis and accidental hypothermia each ranged between 1 and 4% of the cohort. Of all patients, 376 (36%) were discharged in good neurologic condition. Overall, patients with cardiac causes had a significantly better outcome than those with non-cardiac causes (44% vs. 23%, p<0.01). Patients with pulmonary causes survived in 24%. The other subgroups showed widely divergent survival results (3-65%). Patients who had suffered cardiac arrest in the emergency department had a better outcome then patients of the regular ward or radiology department. CONCLUSION In hospital cardiac arrest is caused mainly by cardiac and pulmonary causes, outcome depends on the cause, with a big variability.

Age-specific prognostication after out-of-hospital cardiac arrest – The ethical dilemma between ‘life-sustaining treatment’ and ‘the right to die’ in the elderly:

Background: While prognostic values on survival after out-of-hospital cardiac arrest have been well investigated, less attention has been paid to their age-specific relevance. Therefore, we aimed to identify suitable age-specific early prognostication in elderly patients suffering out-of-hospital cardiac arrest in order to reduce the burden of unnecessary treatment and harm. Methods: In a prospective population-based observational trial on individuals suffering out-of-hospital cardiac arrest, a total of 2223 patients receiving resuscitation attempts by the local emergency medical service in Vienna, Austria, were enrolled. Patients were stratified according to age as follows: young and middle-aged individuals (<65 years), young old individuals (65–74 years), old individuals (75–84 years) and very old individuals (>85 years). Results: There was an increasing rate of 30-day mortality (+21.8%, p < 0.001) and unfavourable neurological outcome (+18.8%, p < 0.001) with increasing age among age groups. Established predictive variables lost their prognostic potential with increasing age, even after adjusting for potential confounders. Independently, an initially shockable electrocardiogram proved to be directly associated with survival, with an adjusted hazard ratio (HR) of 2.04 (95% confidence interval (CI) 1.89–2.38, p = 0.003) for >85-year-olds. Frailty was directly associated with mortality (HR 1.22, 95% CI 1.01–1.51, p = 0.049), showing a 30-day survival of 5.6% and a favourable neurological outcome of 1.1% among elderly individuals. Conclusion: An initially shockable electrocardiogram proved to be a suitable tool for risk assessment and decision making in order to predict a successful outcome in elderly victims of out-of-hospital cardiac arrest. However, the outcomes of elderly patients seemed to be exceptionally poor in frail individuals and need to be considered in order to reduce unnecessary treatment decisions.

Cardiac arrest survivors with moderate elevated body mass index may have a better neurological outcome: A cohort study

AIM Body mass index (BMI) may influence the quality of cardiopulmonary resuscitation and may influence prognosis after cardiac arrest. To review the direct effect of obesity on outcome after cardiac arrest, the following cohort study was conducted. METHODS This study based on a cardiac arrest registry comprising all adult patients with cardiac arrest of non-traumatic origin and restoration of spontaneous circulation (ROSC) admitted to the department of emergency medicine of a tertiary-care facility. Data were collected between January 1992 and December 2007 according to the Utstein criteria. We assessed the association between BMI according to the WHO classification (underweight, BMI<18.5; normal weight, 18.5-24.9; overweight, 25.0-29.9; obese ≥ 30), six-month survival and neurological recovery. RESULTS Analysis was carried out on a total of 1915 adult patients (32% female). Patients had a median age of 59 years (interquartile range [IQR] 49-70) and a median BMI of 26.0 (IQR 23.9-29.1). Survival to six months was 50%. There was no significant difference in survival between the BMI groups (underweight 46%, normal weight 47%, overweight 52%, obese 51%). In a multivariate analysis neurological outcome was better in overweight patients as compared to subjects with normal BMI (odds ratio 1.35; 95% confidence interval 1.02-1.79). CONCLUSION Body mass index may have no direct influence on six-month survival after cardiac arrest, but patients with moderately elevated BMI may have a better neurological prognosis.

The effect of percutaneous coronary intervention in patients suffering from ST-segment elevation myocardial infarction complicated by out-of-hospital cardiac arrest on 30 days survival.

AIM OF THE STUDY To question the beneficial effects of the recommended early percutaneous coronary intervention (PCI) after out-of-hospital cardiac arrest on 30-day survival with favourable neurological outcome. METHODS Prospectively collected data of 1277 out of hospital cardiac arrest patients between 2005 and 2010 from a registry at a tertiary care university hospital were used for a cohort study. RESULTS In 494 (39%) arrest patients ST-segment elevation was identified in 249 (19%). Within 12h after restoration of spontaneous circulation catheter laboratory investigations were initiated in 197 (79%) and PCI in 183 (93%) (78% got PCI in less than 180 min). Adjustment for a cumulative time without chest compressions <2 min, initial shockable rhythm, cardiac arrest witnessed by healthcare professionals, and a higher core temperature at time of hospitalization reduced the effect of PCI on favourable neurological outcome at 30 days (OR 1.40; 95% CI, 0.53-3.7) compared to the univariate analysis (OR 2.52; 95% CI, 1.42-4.48). CONCLUSION This cohort study failed to demonstrate the beneficial effects of PCI as part of post-resuscitation care on 30-day survival with a favourable neurological outcome.

Femoro-iliacal artery versus pulmonary artery core temperature measurement during therapeutic hypothermia: An observational study

AIM OF THE STUDY Therapeutic hypothermia after cardiac arrest improves neurologic outcome. The temperature measured in the pulmonary artery is considered to best reflect core temperature, yet is limited by invasiveness. Recently a femoro-arterial thermodilution catheter (PiCCO-Pulse Contour Cardiac Output) has been introduced in clinical practice as a safe and accurate haemodynamic monitoring system, which is also able to measure blood temperature. The aim of the study was to investigate, if the temperature measured with the PiCCO catheter reflects pulmonary artery temperature better than other sites during therapeutic hypothermia. METHODS In this observational study twenty patients after cardiac arrest and successful resuscitation were cooled with various cooling methods to 33 ± 1°C for 24h, followed by rewarming. Temperatures were recorded continuously in the pulmonary artery (Tpa), femoro-iliacal artery (Tpicco), ear canal (Tear), oesophagus (Toeso) and urinary bladder (Tbla). We assessed agreement of methods using the Bland Altman approach including bias and limits of agreement (LA). RESULTS All other sites differed significantly from Tpa with the bias varying from 0.4°C (Tbla) to -0.6°C (Tear). Standard deviations varied from 0.1°C (Tpicco, Toeso) to 0.5°C (Tear). For all sites bias was closer to zero with increasing average temperatures. Bias tended to be larger in the cooling phase compared to overall measurements. CONCLUSIONS Temperature measurement in the femoro-iliacal artery (Tpicco) reflects the gold standard of pulmonary artery temperature most accurately, especially during the cooling phase. Tpicco is easily accessible and might be used for monitoring core temperature without the need for additional temperature probes.

Rapid induction of mild therapeutic hypothermia by extracorporeal veno-venous blood cooling in humans

AIM Mild therapeutic hypothermia is beneficial in patients successfully resuscitated from non-traumatic out-of-hospital cardiac arrest. The effect of fast induction of hypothermia in these patients remains to be investigated. The aim of this study was to evaluate the efficacy and safety of extracorporeal veno-venous blood cooling in humans successfully resuscitated from cardiac arrest. METHODS We performed an interventional study in patients after successful resuscitation from cardiac arrest admitted to the emergency department of a tertiary care centre. The extracorporeal veno-venous circulation was established via a percutaneously introduced double lumen dialysis catheter in the femoral vein, and a tubing circuit and heat exchanger. A paediatric cardiopulmonary bypass roller pump and a heater-cooler system were used to circulate the blood. Main outcome measures were feasibility, efficacy, and safety. RESULTS We included eight consecutive cardiac arrest patients with a median oesophageal temperature of 35.9°C (interquartile range 34.9-37.0). A median time of 8 min elapsed (interquartile range 5-15 min) to reach oesophageal temperatures below 34°C, which reflects a cooling rate of 12.2°C/h (interquartile range 10.8°C/h to 14.1°C/h). The predefined target temperature of 33.0°C was reached after 14 min (interquartile range 8-21 min). No device or method related adverse events were reported. CONCLUSION Extracorporeal veno-venous blood cooling is a feasible, safe, and very fast approach for induction of mild therapeutic hypothermia in patients successfully resuscitated from cardiac arrest.

Temperature monitored on the cuff surface of an endotracheal tube reflects body temperature

Objective:When treating patients with cardiac arrest with mild therapeutic hypothermia, a reliable and easy-to-use temperature probe is desirable. This study was conducted to investigate the accuracy and safety of tracheal temperature as a measurement of body temperature. Design:Observational cohort study. Setting:Emergency department of a tertiary care university hospital. Patients:Patients successfully resuscitated from cardiac arrest intended for mild hypothermia therapy. Interventions:Intubation was performed with a newly developed endotracheal tube that contains a temperature sensor inside the cuff surface. During the cooling, mild hypothermia maintenance, and rewarming phases, the temperature was recorded minute by minute. These data were compared with the temperature assessed by esophageal and blood temperature probes. Thereafter, tracheoscopy was performed to evaluate the condition of the tracheal mucosa. Measurements and Main Results:Approximately 2000 measurements per temperature sensor per patient were recorded in 21 patients. The mean bias between the blood temperature and the tracheal temperature was −0.16°C (limits of agreement: −0.36°C to 0.04°C). The mean bias between the esophageal and tracheal temperatures was −0.22°C (limits of agreement: −0.49°C to 0.07°C). Agreement between temperature probes investigated by the Bland-Altman method showed a mean bias of less than −¼°C, and time lags assessed graphically by hysteresis plots were negligible. No clinically relevant injury to the tracheal mucosa was detected. Conclusion:Temperature monitoring at the cuff surface of an endotracheal tube is safe and provides accurate and reliable data in all phases of therapeutically induced mild hypothermia after cardiac arrest.

Strategic target temperature management in myocardial infarction—a feasibility trial

Objective The purpose of this study was to demonstrate the feasibility of a combined cooling strategy started out of hospital as an adjunctive to percutaneous coronary intervention (PCI) in the treatment of ST-elevation acute coronary syndrome (STE-ACS). Design Non-randomised, single-centre feasibility trial. Setting Department of emergency medicine of a tertiary-care facility, Medical University of Vienna, Vienna, Austria. In cooperation with the Municipal ambulance service of the city of Vienna. Patients Consecutive patients with STE-ACS presenting to the emergency medical service within 6 h after symptom onset. Interventions Cooling was initiated with surface cooling pads in the out-of-hospital setting, followed by the administration of 1000–2000 mL of cold saline at hospital arrival and completed by endovascular cooling in the catheterisation laboratory. Main outcome measures Feasibility of lowering core temperature below 35.0°C prior to immediately performed revascularisation. Safety and tolerability of the cooling procedure. Results In enrolled 19 patients (one woman, median age 51 years (IQR 45–59)), symptom onset to first medical contact (FMC) was 45 min (IQR 31–85). A core temperature below 35.0°C at reperfusion of the culprit lesion was achieved in 11 patients (78%) within 100 min (IQR 90–111) after FMC without any cooling-related serious adverse event. Temperature could be lowered from baseline 36.4°C (IQR 36.2–36.5°C) to 34.4°C (IQR 34.1–35.0°C) at the time of reperfusion. Conclusions With limitations an immediate out-of-hospital therapeutic hypothermia strategy was feasible and safe in patients with STE-ACS undergoing primary PCI. Clinical trial registration http://www.clinicaltrials.gov/ct2/show/NCT01864343; clinical trials unique identifier: NCT01864343

Prehospital surface cooling is safe and can reduce time to target temperature after cardiac arrest

PURPOSE Mild therapeutic hypothermia proved to be beneficial when induced after cardiac arrest in humans. Prehospital cooling with i.v. fluids was associated with adverse side effects. Our primary objective was to compare time to target temperature of out-of hospital cardiac arrest patients cooled non-invasively either in the prehospital setting vs. the in-hospital (IH) setting, to assess surface-cooling safety profile and long term outcome. METHODS In this retrospective, single center cohort study, a group of adult patients with restoration of spontaneous circulation (ROSC) after out-of hospital cardiac arrest were cooled with a surface cooling pad beginning either in the prehospital or IH setting for 24h. Time to target temperature (33.9°C), temperature on admission, time to admission after ROSC and outcome were compared. Also, rearrests and pulmonary edema were assessed. Neurologic outcome at 12 months was evaluated (Cerebral Performance Category, CPC 1-2, favorable outcome). RESULTS Between September 2005 and February 2010, 56 prehospital cooled patients and 54 IH-cooled patients were treated. Target temperature was reached in 85 (66-117)min (prehospital) and in 135 (102-192)min (IH) after ROSC (p<0.001). After prehospital cooling, hospital admission temperature was 35.2 (34.2-35.8)°C, and in the IH-cooling patients initial temperature was 35.8 (35.2-36.3)°C (p=0.001). No difference in numbers of rearrests and pulmonary edema between groups was observed. In both groups, no skin lesions were observed. Favorable outcome was reached in 26.8% (prehospital) and in 37.0% (IH) of the patients (p=0.17). CONCLUSIONS Using a non-invasive prehospital surface cooling method after cardiac arrest, target temperature can be reached faster without any major complications than starting cooling IH. The effect of early non-invasive cooling on long-term outcome remains to be determined in larger studies.

Seasonal variability and influence of outdoor temperature on body temperature of cardiac arrest victims

AIM OF THE STUDY Mild therapeutic hypothermia is a major advance in post-resuscitation-care. Some questions remain unclear regarding the time to initiate cooling and the time to achieve target temperature below 34 °C. We examined whether seasonal variability of outside temperature influences the body temperature of cardiac arrest victims, and if this might have an effect on outcome. METHODS Patients with witnessed out-of-hospital cardiac arrests were enrolled retrospectively. Temperature variables from 4 climatic stations in Vienna were provided from the Central Institute for Meteorology and Geodynamics. Depending on the outside temperature at the scene the study participants were assigned to a seasonal group. To compare the seasonal groups a Students t-test or Mann-Whitney U test was performed as appropriate. RESULTS Of 134 patients, 61 suffered their cardiac arrest during winter, with an outside temperature below 10 °C; in 39 patients the event occurred during summer, with an outside temperature above 20 °C. Comparing the tympanic temperature recorded at hospital admission, the median of 36 °C (IQR 35.3-36.3) during summer differed significantly to winter with a median of 34.9 °C (IQR 34-35.6) (p<0.05). This seasonal alterations in core body temperature had no impact on the time-to-target-temperature, survival rate or neurologic recovery. CONCLUSION The seasonal variability of outside temperature influences body temperature of out-of-hospital cardiac arrest victims.