Hypertonic sodium bicarbonate for Taxus media-induced cardiac toxicity in swine.
OBJECTIVE
To determine whether intravenous (IV) hypertonic sodium bicarbonate is effective in the reversal of QRS widening associated with severe Taxus intoxication.


METHODS
Seventeen anesthetized and instrumented swine were poisoned with an IV extract of Taxus media until doubling of the QRS interval on electrocardiography was achieved. After poisoning (time zero), the animals received either 4 mL/kg IV 8.4% sodium bicarbonate (experimental group; 6 animals), a similar volume of 0.7% NaCl in 10% mannitol (mannitol group; 6 animals), or nothing (control group; 5 animals). The main outcome parameter was QRS duration. Secondary outcome parameters were mean arterial pressure (MAP), heart rate (HR), and cardiac index (CI = cardiac output/kg). Additionally, arterial pH, partial pressure of carbon dioxide (pCO(2)), and plasma-ionized calcium, sodium, and potassium were monitored.


RESULTS
Taxus toxicity, defined as a 100% increase in QRS duration, was produced in all animals. The animals were similar in regard to baseline and time 0 physiologic parameters as well as amount of Taxus media extract administered. From times 5 through 30 minutes, following assigned treatment, significant increases in QRS duration were detected in the experimental and mannitol groups compared with the control group. A significant lowering of MAP was found in the experimental group compared with the control group. No significant difference between groups was noted in HR or CI. The swine treated with hypertonic sodium bicarbonate had a statistically significant increase in pH, plasma sodium concentration, and base excess compared with the other groups.


CONCLUSIONS
Hypertonic sodium bicarbonate was ineffective in reversing the widening of QRS interval associated with Taxus poisoning in this swine model.
Ruha
Anne-Michelle
AM
Department of Medical Toxicology, Good Samaritan Regional Medical Center, Phoenix, AZ 85006, USA. michelle.ruha@bannerhealth.com
Tanen
David A
DA
Graeme
Kimberlie A
KA
Curry
Steven C
SC
Miller
Mary Beth
MB
Gerkin
Richard
R
Reagan
Christine G
CG
Brandon
Tedd A
TA
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002118:Calcium / Q000097:blood; D004195:Disease Models, Animal; D004562:Electrocardiography / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects*; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D006982:Hypertonic Solutions / Q000008:administration & dosage; D007262:Infusions, Intravenous; D008297:Male; D008353:Mannitol / Q000494:pharmacology; D011041:Poisoning / Q000188:drug therapy*; D011188:Potassium / Q000097:blood; D012964:Sodium / Q000097:blood; D017693:Sodium Bicarbonate / Q000008:administration & dosage*; D013552:Swine; D020946:Taxus / Q000506:poisoning*
D006982:Hypertonic Solutions; D008353:Mannitol; D017693:Sodium Bicarbonate; D012964:Sodium; D011188:Potassium; D002118:Calcium