Hypertonic saline treatment of severe hyperkalemia in nonnephrectomized dogs.
OBJECTIVE
To determine whether a hypertonic saline bolus improves cardiac conduction or plasma potassium levels more than normal saline infusion within 15 minutes of treatment for severe hyperkalemia. Previously with this model, 8.4% sodium chloride (NaCl) and 8.4% sodium bicarbonate (NaHCO(3)) lowered plasma potassium equally effectively.


METHODS
This was a crossover study using ten conditioned dogs (14-20 kg) that received, in random order, each of three intravenous (IV) treatments in separate experiments at least one week apart: 1) 2 mmol/kg of 8.4% NaCl over 5 minutes (bolus); 2) 2 mmol/kg of 0.9% NaCl over one hour (infusion); or 3) no treatment (control). Using isoflurane anesthesia and ventilation (pCO(2) = 35-40 torr), 2 mmol/kg/hr of IV potassium chloride (KCl) was infused until conduction delays (both absent p-waves and >/=20% decrease in ventricular rate in </=5 minutes) were sustained for 15 minutes. The KCl was then decreased to 1 mmol/kg/hr (maintenance) for 2 hours and 45 minutes. Treatment (0 minutes) began after 45 minutes of maintenance KCl.


RESULTS
From 0 to 15 minutes, mean heart rate increased 29.6 (95% CI = 12.2 to 46; p < 0.005) beats/min more with bolus than infusion and 23.4 (95% CI = 2.6 to 43.5; p < 0.03) beats/min more with bolus than control. No clinically or statistically significant difference was seen in heart rate changes from 0 to 30 minutes. Decreases in potassium from 0 to 15 minutes were similar with bolus, infusion, and control.


CONCLUSIONS
In this model, 8.4% NaCl bolus reversed cardiac conduction abnormalities within the first 15 minutes after treatment, more rapidly than did the 0.9% NaCl infusion or control. This reversal occurred despite similar reductions in potassium levels.
Kaplan
J L
JL
Department of Emergency Medicine, Office for Research and Technology Development, Albert Einstein Medical Center, Philadelphia, PA, USA. kaplanj@aehn2.einstein.edu
Eynon
C A
CA
Dalsey
W C
WC
Braitman
L E
LE
Clas
D
D
De Garavilla
L
L
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D018592:Cross-Over Studies; D004285:Dogs; D006329:Heart Conduction System / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects; D006947:Hyperkalemia / Q000188:drug therapy*; D023421:Models, Animal; D011188:Potassium / Q000097:blood; D011897:Random Allocation; D012462:Saline Solution, Hypertonic / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use*
D012462:Saline Solution, Hypertonic; D011188:Potassium