Hematologic and chemical changes observed during and after cardiac arrest in a canine model--a pilot study.

STUDY OBJECTIVE To evaluate the effect of cardiac arrest and cardiopulmonary resuscitation (CPR) on blood chemistry in a canine model. DESIGN Evaluative canine animal study. SETTING Animal laboratory accredited by the Association for Assessment and Accreditation of Laboratory Animals. SUBJECTS Twenty-six adult mongrel dogs. INTERVENTION The dogs underwent an episode of induced fibrillatory cardiac arrest for 3 minutes followed by 10 minutes of standard CPR. Blood samples were taken at baseline (before cardiac arrest), after 10 minutes of ventricular fibrillation, and 10 minutes after successful resuscitation for determination of blood chemistries and hematologic parameters. MEASUREMENTS AND MAIN RESULTS Glucose, blood urea nitrogen, serum creatinine, sodium, potassium, chloride, calcium, phosphorus, uric acid, alkaline phosphatase, lactate dehydrogenase, aspartate aminotransferase, alanine aminotransferase, protein, albumin, cholesterol, triglycerides, iron, white blood cell count, red blood cell count, and hematocrit were measured. Significant changes (p<0.05) in values obtained during CPR versus baseline values were noted for all laboratory parameters except blood urea nitrogen, chloride, and alkaline phosphatase. Eighteen dogs achieved return of spontaneous circulation (ROSC); their laboratory values were obtained after CPR. Significant changes (p<0.05) after ROSC compared with baseline were noted for all laboratory values except chloride, blood urea nitrogen, uric acid, alkaline phosphatase, glucose, potassium, calcium, triglycerides, iron, red blood cell count, and hematocrit. CONCLUSION Results indicate that significant changes in blood chemistries and hematologic parameters occur during and after CPR. Clinicians should note these normal laboratory parameter changes when interpreting laboratory data in patients who experience cardiac arrest.