Emergency extracorporeal life support and ongoing resuscitation: a retrospective comparison for refractory out-of-hospital cardiac arrest.

BACKGROUND: In refractory cardiac arrest, with cardiopulmonary resuscitation (CPR) for more than 30 min, chances of survival are small. Extracorporeal cardiopulmonary resuscitation (ECPR) is an option for certain patients with cardiac arrest. The aim of this study was to evaluate characteristics of patients selected for ECPR. METHODS: Anonymised data of adult patients suffering refractory cardiac arrest, transported with ongoing CPR to an ED of a tertiary care centre between 2002 and 2012 were analysed. Outcome measure was the selection for ECPR. Secondary outcome was 180 days survival in good neurological condition. RESULTS: Overall, 239 patients fulfilled the inclusion criteria. ECPR was initiated in seven patients. Patients treated with ECPR were younger (46 vs 60 years; p=0.04), had shorter intervals before CPR was started (0 vs 1 min; p=0.013), faster admissions at the ED (38 vs 56 min; p=0.31) and lower blood glucose levels on admission (14 vs 21 mmol/L; p=0.018). Survival to discharge in good neurological condition was achieved in 14 (6%) of all patients. One patient in the ECPR group survived in excellent neurological condition. Age was independently associated with the selection for ECPR (OR 0.07; 95% CI 0.01 to 0.85; p=0.037). CONCLUSIONS: Emergency extracorporeal life support was used for a highly selected group of patients in refractory cardiac arrest. Several parameters were associated with the decision, but only age was independently associated with the selection for ECPR. The patient selection resulting in a survival of one patient out of seven treated seems reasonable. Randomised controlled trials evaluating the age limit as selection criteria are urgently needed to confirm these findings.

Cerebral and Peripheral Metabolism to Predict Successful Reperfusion After Cardiac Arrest in Rats: A Microdialysis Study.

BACKGROUND: In clinical practice, monitoring of the efficacy of resuscitation can be challenging. The prediction of cerebral and overall outcome in particular is an unmet medical need. Microdialysis is a minimally invasive technique for the continuous determination of metabolic parameters in vivo. Using this technique, we set out to establish a model allowing for concomitant determination of cerebral and peripheral metabolism in a cardiac arrest setting in rodents. METHODS: Microdialysis settings were optimized in vitro and then used in male Sprague-Dawley rats. Probes were implanted into the CA1 region of the right hippocampus and the right femoral vein. With a time interval of 8 min, glucose, lactate, pyruvate, and glutamate levels were determined during baseline conditions, untreated ventricular fibrillation cardiac arrest, cardiopulmonary resuscitation (CPR), reperfusion, and death. RESULTS: In 16 rodents, restoration of spontaneous circulation was achieved in seven animals. Characteristic metabolic changes were evident during cardiac arrest and reperfusion with both probes. Ischemic patterns in peripheral compartments were delayed and more variable compared to the changes in cerebral metabolism highlighting the importance of cerebral metabolic monitoring. Microdialysis allowed distinguishing between survivors and non-survivors 8 min after termination of CPR. Cerebral glutamate showed a trend toward higher levels in non-survivors during CPR. CONCLUSIONS: We established a new rodent model for research in hypoxic ischemic encephalopathy. This setting allows to investigate the impact of resuscitation methods on cerebral and peripheral metabolism simultaneously. The present model may be used to evaluate different resuscitation strategies in order to optimize brain survival in future studies.

Cardiac arrest due to accidental hypothermia--a 20 year review of a rare condition in an urban area.

BACKGROUND: Accidental hypothermic cardiac arrest is associated with unfortunate prognosis and large studies are rare. We therefore have performed an outcome analysis in patients that were admitted to Vienna University Hospital with the diagnosis of accidental hypothermic cardiac arrest. METHODS: This study employed a retrospective outcome analysis of prospectively collected data in a selected cohort of hypothermic cardiac arrest patients. We screened 3800 cardiac arrest patients, treated at our department between 1991 and 2010, for eligibility. Inclusion criteria were cardiac arrest with a body core temperature ≤28 °C and return of spontaneous circulation. RESULTS: A total of 18 patients who achieved return of spontaneous circulation were analysed. Nine patients (50%) achieved survival in good neurologic condition (defined as cerebral performance category CPC 1 or 2). Accidental hypothermia with consecutive cardiac arrest was caused by intoxication in most cases (67%). These patients had a better outcome than patients with other causes of accidental hypothermic cardiac arrest (OR=28; 95%KI 2-37.9; p<0.01). Hypothermia associated typical ECG changes after return of spontaneous circulation (Osborne waves) were more frequent in the surviving population (OR 16; 95%KI 1.3-19.5; p=0.05). CONCLUSIONS: Accidental hypothermic cardiac arrest in a central European urban area is rare. Prognosis was excellent in patients where hypothermic cardiac arrest was caused by intoxication.

Decreased renal function in hypertensive emergencies.

Data about acute renal function in hypertensive crises are scarce. We hypothesised that acute kidney damage could result from hypertensive emergency (HE), as indicated by the earliest biomarker of kidney injury, neutrophil gelatinase-associated lipocalin (NGAL). Thus, we compared renal function between patients with HE, patients with urgencies and normotensive controls. Sixty emergency department patients were enroled in a prospective, cross-sectional study. Creatinine, blood urea nitrogen (BUN), NGAL and cystatin C were measured and estimated glomerular filtration rate was calculated (eGFR). Creatinine and BUN were significantly higher and eGFR was significantly lower in HE as compared with urgencies or controls (P < 0.01). Similarly, cystatin C and NGAL levels were significantly higher in emergencies compared with the other groups (P < 0.001). All renal function parameters were similar between urgencies and controls. Among HE, NGAL was significantly higher (61%) in patients with pulmonary oedema than in those with cerebral events (P = 0.008), whereas the other parameters were not significantly different. In conclusion, this cross-sectional investigation showed that markers of acute and chronic kidney injury were higher in patients with HE than in urgencies or controls. These results should encourage further studies to better characterise the role of acute kidney damage in hypertensive pulmonary oedema, and HE in general.

Hypertensive emergencies are associated with elevated markers of inflammation, coagulation, platelet activation and fibrinolysis.

Data from in vitro and animal experiments suggest that progressive endothelial damage with subsequent activation of coagulation and inflammation have a key role in hypertensive crisis. However, clinical investigations are scarce. We hypothesized that hypertensive emergencies are associated with enhanced inflammation, endothelial- and coagulation activation. Thus, we enrolled 60 patients admitted to an emergency department in a prospective, cross-sectional study. We compared markers of coagulation, fibrinolysis (prothrombin fragment F(1+2), plasmin-antiplasmin complexes, plasmin-activator inhibitor, tissue plasminogen activator), platelet- and endothelial activation and inflammation (P-selectin, C-reactive protein, leukocyte counts, fibrinogen, soluble vascular adhesion molecule-1, intercellular adhesion molecule-1, myeloperoxidase and asymmetric dimethylarginine) between hypertensive emergencies, urgencies and normotensive patients. In hypertensive emergencies, markers of inflammation and endothelial activation were significantly higher as compared with urgencies and controls (P<0.05). Likewise, plasmin-antiplasmin complexes were 75% higher in emergencies as compared with urgencies (P<0.001), as were tissue plasminogen-activator levels (∼30%; P<0.05) and sP-selectin (∼40%; P<0.05). In contrast, similar levels of all parameters were found between urgencies and controls. We consistently observed elevated markers of thrombogenesis, fibrinolysis and inflammation in hypertensive emergencies as compared with urgencies. Further studies will be needed to clarify if these alterations are cause or consequence of target organ damage.