Refractory asystole and death following the prehospital administration of adenosine

Adenosine and the Cardiovascular System: The Good and the Bad

Adenosine is a nucleoside that impacts the cardiovascular system via the activation of its membrane receptors, named A₁R, A_2AR, A_2BR and A₃R. Adenosine is released during hypoxia, ischemia, beta-adrenergic stimulation or inflammation and impacts heart rhythm and produces strong vasodilation in the systemic, coronary or pulmonary vascular system. This review summarizes the main role of adenosine on the cardiovascular system in several diseases and conditions. Adenosine release participates directly in the pathophysiology of atrial fibrillation and neurohumoral syncope. Adenosine has a key role in the adaptive response in pulmonary hypertension and heart failure, with the most relevant effects being slowing of heart rhythm, coronary vasodilation and decreasing blood pressure. In other conditions, such as altitude or apnea-induced hypoxia, obstructive sleep apnea, or systemic hypertension, the adenosinergic system activation appears in a context of an adaptive response. Due to its short half-life, adenosine allows very rapid adaptation of the cardiovascular system. Finally, the effects of adenosine on the cardiovascular system are sometimes beneficial and other times harmful. Future research should aim to develop modulating agents of adenosine receptors to slow down or conversely amplify the adenosinergic response according to the occurrence of different pathologic conditions.

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.

Proarrhythmic effects of adenosine: a review of the literature

Adenosine is widely used as an antiarrhythmic agent for the investigation and management of both narrow complex and, less often, broad complex tachycardias. Over the past 10 years or so, reports of severe bradycardias and tachyarrhythmias being induced by this agent have appeared in the literature. As adenosine is increasingly used in emergency departments and indeed outside the hospital setting, a greater awareness of these potential problems is important. In this paper the evidence for such effects is summarised, and the mechanisms involved discussed.

Disaster preparation and management for the intensive care unit

The purpose of this report is to provide information regarding preparation for disaster management from the perspective of ICU physicians. Both a framework toward ICU preparation for disaster management and a guide to the relevant literature are presented. Our objective is to show that the understanding of disaster preparedness on multiple levels, including government, hospital, ICU, and clinician, may lead to optimal management in a disaster.