Category: Critical Care
Keywords: Calcium, Cardiac Arrest, ACLS, Code Blue (PubMed Search)
There are several well known medications that we tend to give by default during cardiac arrests. It seems like for each of them, every few years someone does an RCT to see if they really help anybody, and we're all disappointed by what they find. Well... prepare to be disappointed again, I'm afraid.
These Danish authors randomized 391 patients in cardiac arrest to either calcium or saline (given IV or IO). They gave 2 doses of either calcium chloride or saline, with the first dose being along with the first epi dose. Primary outcome was ROSC. They also looked at modified Rankin at 30 and 90 days.
The trial was stopped early for harm. Now, we all know the dangers of interpreting studies that were stopped early, but this doesn't look great for calcium. 19% of the calcium group had ROSC compared to 27% of the saline group (p = 0.09). Percentage of patients alive, and with favorable mRS at 30 days also both favored the saline group (although also not statistically significantly). By the way, of the patients who had calcium levels sent, 74% in the calcium group, vs 2% in the saline group, were hypercalcemic. Whether that had anything to do with the outcome, we may never know.
Bottom Line: Is this saying that calcium hurts patients in cardiac arrest? Maybe... but I don't think this is high quality enough data to draw that conclusion. At the very least, however, just giving everyone in arrest calcium is probably not terribly helpful. If you have a reason to give it (known severe hypocalcemia, recent parathyroid surgery, suspected hyperkalemia, etc) then go for it, otherwise you can probably focus your resus on more important things.
Vallentin MF, Granfeldt A, Meilandt C, et al. Effect of Intravenous or Intraosseous Calcium vs Saline on Return of Spontaneous Circulation in Adults With Out-of-Hospital Cardiac Arrest: A Randomized Clinical Trial. JAMA. 2021;326(22):2268–2276. doi:10.1001/jama.2021.20929