Does Calcium Work for PEA in Suspected Hyperkalemia?
December 29, 2022
Written by Alex Clark
Spoon Feed
Empiric calcium administration in PEA arrest not only failed to improve ROSC, but also had no impact when ECG features of hyperkalemia and acute myocardial ischemia were present.
Why does this matter?
Many EM providers utilize calcium universally in PEA arrest. In fact, one trial in 1985 demonstrated increased ROSC in PEA arrest given calcium with widened QRS-complexes, peaked T-waves, or ST-elevations. However, recent studies have called calcium into question for both out-of-hospital cardiac arrest (OHCA) and in-hospital cardiac arrest, and current guidelines recommend it only when there is strong clinical suspicion for hyperkalemia.
Strong bones, strong heart?
This was a preplanned substudy of the recently published Calcium for Out-of-hospital Cardiac Arrest (COCA) Trial: a randomized, placebo-controlled, double-blind trial conducted across the Central Denmark Region. It included 104 patients who presented with PEA. Outcomes were compared between patients who received 10 mL of 0.5 mmol/mL calcium chloride (n = 45) versus 9 mg/mL sodium chloride (n = 59) after their first dose of epinephrine. The primary outcome was ROSC. Changes in electrocardiographic characteristics after the intervention drug were also reviewed including hyperkalemic (ie. loss of P-waves, QRS-widening, and positive T-wave amplitude above the median) and acute myocardial ischemic (ST-segment elevations and depressions, T-wave inversions) features.
Overall, there was no statistically significant difference in ROSC between the calcium (n = 9; 20%) intervention compared to placebo (n = 23; 39%; risk ratio 0.51; 95% CI 0.26, 1.00). Additionally, there was a non-statistically significant trend toward decreased 30-day survival in the calcium group, risk ratio 0.16 (95%CI 0.02-1.26). Subgroup analyses regarding ECG characteristics also showed no effect modification.
Although a small sample size in an OHCA population very different from where many of us practice (85% bystander CPR!!!), this is a reminder that calcium is a medication, and like most medications, one with its own set of side effects. In the anuric, AV-fistula patient with sinusoidal PEA arrest after missing dialysis – sure, let’s try calcium. But if I need to squint to see mildly peaked T-waves… I will stick to CPR, epinephrine, and identifying other reversible causes for now.
Source
Effect of Calcium in Patients with Pulseless Electrical Activity and Electrocardiographic Characteristics Potentially Associated with Hyperkalemia and Ischemia-Sub-study of the Calcium for Out-of-hospital Cardiac Arrest (COCA) trial. Resuscitation. 2022 Nov 17;S0300-9572(22)00712-2. doi: 10.1016/j.resuscitation.2022.11.006. Online ahead of print.