Extracorporeal cardiopulmonary resuscitation, selection and candidacy

Extracorporeal cardiopulmonary resuscitation (ECPR) is an exclusive treatment using extracorporeal membrane oxygenation (ECMO) in refractory cardiac arrest (CA). Treatment is associated with risk of serious complications, including neurologic impairment and renal failure. Success of treatment is dependent on appropriate selection of candidates. The aim of this thesis was to investigate the role of end-tidal carbon dioxide (ETCO2), as a selection criterion for ECPR. Moreover, to define and describe the potential ECPR-cohort in Sweden and investigate conditions for a national ECPR-program. Experimental porcine models of CA were used in studies I and II. CA was induced, and cardiopulmonary resuscitation (CPR) was performed. Physiological parameters, biochemical markers and histology were evaluated in relation to ETCO2. In study I, ECMO was started at a predetermined time of CPR. Levels of ETCO2 during CPR was found to be associated with the extent of cerebral and renal injury following ECPR. In study II, the same model was used. However, start of ECMO was triggered by a predetermined threshold of ETCO2 during CPR. Results suggest that ETCO2 could be used as a marker for brain injury following ECPR. Extract from The Swedish Cardiac Arrest Registry formed the data basis for studies III and IV. Internationally proposed selection criterion for ECPR was applied to the data. ECPR-eligible cohorts were defined and described. In study III, data on in-hospital cardiac arrests was assessed. Results showed low numbers of ECPR-eligible patients annually. Estimates of gain of ECPR suggested a limited benefit in survival and neurological outcome, if ECMO was started within 60 min. In study IV, data on out-of hospital cardiac arrests was assessed. Low numbers of candidates suggested that only a minority of ECPR-capable hospitals in Sweden have a population base large enough to justify an ECPR-program. In conclusion, this thesis has demonstrated a correlation between ETCO2 during CPR and the resulting injury in brain and kidney ...