Calcium: A Drug of Abuse in Cardiac Arrest?

Calcium is commonly administered during in-hospital cardiac arrest (IHCA) to improve contractility and vascular tone, and as a myocardial protection agent and anti-dysrhythmia adjunct for patients with suspected hyperkalemia (Moskowitz, 2019). Advanced Cardiac Life Support (ACLS) guidelines do not support its routine use. Recent work has suggested worse outcomes for out-of-hospital cardiac arrest (OHCA) when calcium was used early in the arrest, and for IHCA when calcium was used in pediatric patients and adults (Dhillon, 2022; Vallentin, 2022; Messias, 2022; Gill, 2021). Calcium use is not, however, consistent throughout the code and we suspect data is skewed by “Immortality Bias,” where patients who achieve early ROSC were at little “risk” of calcium receipt, and patients who are not responding to therapies and at high risk of poor outcome are given “last-ditch” therapies, including calcium.  Additionally, IHCA and OHCA occur due to distinct etiologies, with IHCA being more likely to occur related to hyperkalemia and hypotension, both of which may be responsive to calcium administration. 

The physiology of calcium use and prior work in cardiac arrest and ischemia reperfusion states will be reviewed, as well as data obtained by the speaker assessing the use of calcium during IHCA in a time-stratified way in hopes of resolving the immortality bias.