What is the Bezold-Jarisch reflex?
Mechanoreceptors in the left ventricle activate inhibitory vagal afferents to increase sympathetic tone and guard the body against hypotension. This protective physiologic response occurs during times of severe stress, such as hemorrhage. The Bezold-Jarisch reflex is a para-doxical activation of these left ventricular receptors by a decrease in venous return, causing a decrease in sympa-thetic tone with an increase in vagal outflow. This pro-duces severe bradycardia and hypotension, which can lead to asystole.
Patients undergoing shoulder repair are at risk for acti-vating this reflex. The “beach chair” position causing pool-ing of blood in the lower extremities, patient anxiety and the addition of epinephrine to the arthroscopy infusate are all factors contributing to this phenomenon.
Ephedrine is the treatment of choice because it has a direct action on the heart and peripheral activation of cat-echolamines. Fluid resuscitation is important to prevent further stimulation of these receptors. If progression to asystole occurs, epinephrine is essential. Atropine will not adequately treat this event, should it occur.