Is there a role for remote ischaemic postconditioning in cardiopulmonary resuscitation?

Ischemia reperfusion injury as a modifiable therapeutic target for cardioprotection or neuroprotection in patients undergoing cardiopulmonary resuscitation

AIMS

We sought to review cellular changes that occur with reperfusion to try to understand whether ischemia-reperfusion injury (RI) is a potentially modifiable therapeutic target for cardioprotection or neuroprotection in patients undergoing cardiopulmonary resuscitation.

DATA SOURCES

Articles written in English and published in PubMed.

RESULTS

Remote ischemic conditioning (RIC) involves brief episodes of non-lethal ischemia and reperfusion applied to an organ or limb distal to the heart and brain. Induction of hypothermia involves cooling an ischemic organ or body. Both have pluripotent effects that reduce the potential harm associated with RI in the heart and brain by reduced opening of the mitochondrial permeability transition pore. Recent trials of RIC and induced hypothermia did not demonstrate these treatments to be effective. Assessment of the effect of these interventions in humans to date may have been modified by use of concurrent medications including propofol.

CONCLUSIONS

Ongoing research is necessary to assess whether reduction of RI improves patient outcomes.

Evaluation of remote ischaemic post-conditioning in a pig model of cardiac arrest: A pilot study

BACKGROUND

Remote ischaemic post-conditioning (RIPoC) in which transient episodes of ischaemia (e.g. by inflation and deflation of a blood pressure cuff) are applied after a prolonged ischaemia/reperfusion injury, may have the potential to improve patient outcome and survival following cardiac arrest. In this study we employed a pig model of cardiac arrest and successful cardiopulmonary resuscitation to evaluate the effects of RIPoC on haemodynamics, cardiac tissue damage and neurologic deficit.

MATERIALS AND METHODS

A total of 22 pigs were subjected to ventricular fibrillation, cardiopulmonary resuscitation and randomly assigned to Control or RIPoC treatment consisting of 4 cycles of 5 min femoral artery occlusion followed by 5 min of reperfusion starting 10min after return of spontaneous circulation (ROSC). Post-resuscitation was evaluated by haemodynamics using left ventricular conductance catheters, quantification of cardiac troponin T (cTnT), lactate dehydrogenase (LDH) and creatine kinase (CK). Neurological testing was performed 24h after return of spontaneous circulation (ROSC).

RESULTS

RIPoC resulted in a statistically significant reduction of serum cTnT levels 4h after ROSC (P ≤ 0.01). LDH and CK concentrations were significantly lower in RIPoC treated pigs 24h after ROSC (P ≤ 0.001), suggesting tissue and/or cardioprotective effects of RIPoC. End-systolic pressure volume relationship was significantly increased in RIPoC treated animals 4h after ROSC (P ≤ 0.05). Neurological testing revealed a trend towards an improved outcome in RIPoC treated animals.

CONCLUSIONS

We propose that RIPoC applied immediately after ROSC reduces serum concentrations of markers for cell damage and improves end-systolic pressure volume relationship 4h after ROSC.

Improving bystander cardiopulmonary resuscitation

PURPOSE OF REVIEW

Summary estimates indicate that bystander cardiopulmonary resuscitation (CPR) can improve the chances of out-of-hospital cardiac arrest survival two-fold to three-fold. And yet, only a minority of arrest victims receive bystander CPR. This summary will review the challenges and approaches to achieve early and effective bystander CPR.

RECENT FINDINGS

Given the host of barriers, a successful strategy to improve bystander CPR must enable more timely and comprehensive arrest identification, encourage and empower bystanders to act, and help assure effective CPR. Arrest identification can be simplified so that bystanders should start CPR when a person is unconscious and not breathing normally. Evidence from observational studies and interventional trials supports the effectiveness of chest compression-only CPR for bystanders. As a consequence, the emphasis of bystander CPR training has been modified to feature and assure chest compressions. Bystanders should initiate CPR with compressions and consider the addition of rescue breathing based on their CPR training and skills as well as special circumstances of the victim. Bystander CPR training has evolved to incorporate this emphasis. Although general community-level CPR training remains a cornerstone strategy, training directed to those most likely to witness an arrest also has a useful role. In particular, 'just-in-time' dispatcher-assisted CPR instruction can increase bystander CPR and improve the likelihood of survival.

SUMMARY

Recent developments in bystander CPR have simplified arrest recognition and improved CPR training, while retaining CPR effectiveness. The goal of these developments is to increase and improve bystander CPR and in turn improve resuscitation.