Cardiopulmonary arrest in spinal anesthesia

Spinal anesthesia is an integral part of the daily routine of countless anesthesiologists. It is considered to be a safe procedure, although some complications related to this technique, among them the most feared is cardiopulmonary arrest (cardiac arrest, CA), do exist. The real incidence of CA related to spinal anesthesia, as well as its etiology, is not known and has motivated this review article.

Articles published in the last twenty years in Medline indexed journals and in a textbook were reviewed. The objective of the present review was to identify the incidence of spinal block anesthesia-related CA and the etiology of those cases. We also tried to identify possible risk factors. Finally, treatment strategies described in the literature were reviewed in order to determine the best conduct when facing a case of CA during spinal anesthesia.

The incidence of spinal anesthesia-related CA varies, and it seems to be lower when compared to that of general anesthesia. In the past, it was believed that CA was due to hypoxemia related especially to excessive sedation. However, nowadays, it is known that the etiology of CA during spinal block anesthesia is related to cardiocirculatory factors, mainly a reduction of preload resulting from sympathetic blockade. Other factors that increase the risk of developing CA also exist. Among those factors, the following should be mentioned: changes in patient positioning and hypovolemia. It is very important to institute treatment as soon as possible. Besides a vagolytic agent, early use of a sympathomimetic drug, especially adrenaline, is also recommended to minimize damage to the patient.