The effect of calcium chloride in treating hyperkalemia due to acute digoxin toxicity in a porcine model.
BACKGROUND
The administration of intravenous (IV) calcium to treat hyperkalemia resulting from digoxin poisoning is considered potentially dangerous, based on a body of older literature which, in sum, reported increased cardiac glycoside toxicity with calcium administration (increased arrhythmias, higher rate of death).


OBJECTIVE
This pilot study sought to determine if the administration of calcium chloride when compared to normal saline would affect time to death when given to hyperkalemic, digoxin toxic swine.


METHODS
Digoxin IV at 0.25 mg/kg was determined to be appropriately toxic for this study. When arrhythmias consistent with hyperkalemia developed, animals were given either IV calcium chloride (CaCl) bolus (10 mg/kg, Group 1, n=6) or normal saline volume equivalent (Group 2, n=6). Three intervals were observed: Interval 1: time interval from digoxin administration (T0) to when ECG changes consistent with hyperkalemia developed (at which point calcium chloride or normal saline was administered); Interval 2: time interval from the development of ECG changes consistent with hyperkalemia to asystole; Interval 3: time interval from digoxin administration to asystole. Both groups were monitored for changes in heart rhythms, serum potassium levels, and time to asystole.


RESULTS
The intravenous digoxin dose of 0.25 mg/kg induced hyperkalemia, arrhythmias, and death approximately 1 h after administration in all animals studied. Group 1: Interval 1 averaged 18.75 (S.D. +/-7.96) min, Interval 2 averaged 16.75 (S.D. +/-17.17) min, and Interval 3 averaged 35.5 (S.D. +/-14.49) min range; Group 2: average Interval 1 24.8 (S.D. +/-4.71) min, Interval 2 averaged 19.5 (S.D.+/-15.92), Interval 3 averaged 44.3 (S.D. +/-13.80) minutes. There was no statistically significant difference between the groups at any time interval, Interval 1 (p=0.43), Interval 2 (p=0.65), Interval 3 (p=0.40). There was no difference in serum potassium throughout the study period.


CONCLUSIONS
The administration of intravenous CaCl in the setting of hyperkalemia from acute digoxin toxicity did not affect mortality or time to death at the dose administered.
Hack
Jason B
JB
Division of Toxicology, Department of Emergency Medicine, The Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA. hackj@mail.ecu.edu
Woody
Jonathan H
JH
Lewis
Daniel E
DE
Brewer
Kori
K
Meggs
William J
WJ
D000818:Animals; D002122:Calcium Chloride / Q000008:administration & dosage*; D002316:Cardiotonic Agents / Q000506:poisoning*; D004077:Digoxin / Q000506:poisoning*; D004195:Disease Models, Animal; D004562:Electrocardiography / Q000187:drug effects; D006947:Hyperkalemia / Q000097:blood / Q000139:chemically induced / Q000188:drug therapy* / Q000401:mortality; D007275:Injections, Intravenous; D010865:Pilot Projects; D011041:Poisoning / Q000188:drug therapy; D011188:Potassium / Q000097:blood; D011897:Random Allocation; D013552:Swine
D002316:Cardiotonic Agents; D004077:Digoxin; D002122:Calcium Chloride; D011188:Potassium