During the post cardiac arrest phase, an emphasis is placed on improving perfusion by optimizing myocardial function.
Myocardial function and systemic perfusion can be optimized by providing interventions that alter the components of cardiac output which include heart rate, and stroke volume (preload, afterload (SVR), and contractility).
Remember: Heart Rate x Stroke Volume (preload, afterload, contractility) = Cardiac Output
The interventions for each component of cardiac output are provided below.
There are several methods for increasing or decreasing the heart rate to improve systemic perfusion. If poor perfusion is a result of a slow heart rate, the administration of chronotropic medications such as epinephrine can be used to increase the heart rate.
If poor perfusion caused by bradycardia is the result of hypoxia then correcting the hypoxic condition can significantly improve the heart rate.
Transcutaneous pacing can also be used to regulate the heart rate and improve systemic perfusion.
If poor systemic perfusion is the result of tachyarrhythmias, antiarrhythmics can be used to improve systemic perfusion.
Poor perfusion can result when preload is decreased. Decreased preload can have a significant effect on the cardiac output. The primary method used to improve preload is the administration of fluid boluses as discussed in the section on hypovolemic shock.
Afterload (systemic vascular resistance):
Afterload may need to be increased or decreased depending on the cause of poor perfusion after ROSC.
Vasoconstrictors can be used to increase afterload (systemic vascular resistance) and vasodilators can be used to decrease systemic vascular resistance.
During the post-arrest phase, contractility of the heart can be compromised due to a number of factors. Major factors that may need to be corrected include hypoxia, electrolyte imbalances, hypoglycemia, and hypocalcemia.
Also, inotropes and inodilators can be used to temporarily improve cardiac contractility through the acute post arrest phase.
Some types of poisoning can also result in decreased cardiac contractility and administration of antidotes should be considered when necessary.
See Management of Post Arrest Shock Algorithm for a summary of the above information.