How often should adrenaline be administered during CPR for asystole or PEA?

The correct interval for administering adrenaline during CPR for asystole or pulseless electrical activity (PEA) is every 3-5 minutes. This timing is based on guidelines that aim to maximize the effectiveness of adrenaline in cases of cardiac arrest. Frequent administration of adrenaline is crucial as it helps to increase coronary perfusion pressure, which can improve the chances of successful resuscitation.

In the setting of cardiac arrest, particularly in asystole or PEA, the heart is not effectively circulating blood. Therefore, the mechanism of action of adrenaline is important. It acts primarily as a vasoconstrictor, which enhances blood flow to the heart and brain during the critical moments of CPR. Administering adrenaline every 3-5 minutes ensures that there is a continuous supply of the drug acting on the cardiovascular system, improving the likelihood of restoring a spontaneous heartbeat.

The other options either suggest too frequent administration, may cause confusion about the timing without a need for immediate physiological feedback, or imply that adrenaline is only given under specific conditions, which does not align with resuscitation protocols. Thus, adhering to the 3-5 minute window is essential for achieving the best possible outcomes during advanced resuscitation efforts.