Extracorporeal life-support in patients requiring CPR.

In today’s Lancet, Yih-Sharng Chen and colleagues show the possible benefi ts of extracorporeal life-support in adults receiving cardiopulmonary resuscitation (CPR) in hospital for more than 10 min for problems of cardiac origin. Irrespective of the advancements made in con ventional CPR, median survivals to discharge after involvement of emergency medical services are only 6·4% for out-of-hospital cardiac arrest and 13·4–17·0% for in-hospital arrest. The probable causes of high mortality in cardiac arrest are: a lack of return to spontaneous circulation; re-arrest after such a lack of return because of haemodynamic instability; and late death because of multiple organ dysfunction, including hypoxic brain injury due to ischaemic or reperfusion injury. Extracorporeal life-support in cardiac arrest uses a percutaneous system that incorporates the rapid initiation of femoral-femoral venoarterial cardio pulmonary bypass by a trained vascular-access team, followed by the extracorporeal maintenance of cir culation until an eff ective cardiac output has been achieved (fi gure). Extracorporeal circulation enhances coronary blood fl ow and preserves myocardial viability, and thus reduces time to the return of spontaneous circulation. Also, extracorporeal life-support supplies oxygenated blood to multiple organs, prevents organ dysfunctions, and increases the likelihood of late survival after cardiac arrest. Moreover, during extracorporeal life-support, causes of arrest can be diagnosed and defi nitive treatments that target underlying causes can be started. Additionally, hypothermia can be easily induced to reduce hypoxic brain injury. Extracorporeal life-support in cardiac arrest has been described as a means to improve survival and as an extension of conventional CPR. However, no criteria are available to identify appropriate candidates for the procedure, and the upper limit for continuing CPR before extracorporeal life-support has not been established in terms of neurological outcomes. The 2005 American Heart Association guidelines for CPR and emergency cardiovascular care recommend that extracorporeal life-support should be considered for patients in hospital who have a cardiac arrest when the duration of no-fl ow arrest is brief and the condition leading to the arrest is reversible (class IIb). Moreover, protracted CPR decreases survival rates both during extracorporeal life-support and conventional CPR. Thus extracorporeal life-support is probably better used as soon as possible to keep ischaemic times to a minimum and improve outcomes. Chen and colleagues conclude that extracorporeal life-support benefi ts patients who have in-hospital cardiac arrest of cardiac origin and receive conventional CPR for more than 10 min. Furthermore, available results indicate that the application of extracorporeal life-support in cardiac arrest improves survival and the likelihood of a satisfactory neurological outcome. However, no study has provided clear evidence of the merits of extracorporeal life-support in patients with out-of-hospital cardiac arrest, although many case reports and case series have concluded about its eff ectiveness. Cardiotoxicity, severe accidental hypo thermia, and recurrent ventricular fi brillation are three widely accepted indications for emergency cardiopulmonary bypass support in patients with protracted cardiopulmonary arrest outside the catheter laboratory. Shin and colleagues reported a successful resuscitation after out-of-hospital arrest in a patient with recurrent ventricular fi brillation who was unresponsive to conventional CPR. Thus we hope that extracorporeal life-support will be extended to Published Online July 7, 2008 DOI:10.1016/S01406736(08)60959-9