Possible effects of acute hypovolemia in dogs anesthetized with isoflurane on the electrocardiography were evaluated. It was observed duration and amplitude of P wave (Ps and PmV), interval between P-R waves (P-R), duration of QRS complex (QRS), amplitude of R wave (RmV), interval between Q-T waves (Q-T) and interval between two R waves (R-R), heart rate (HR), cardiac (CI) and stroke index (SI), and systolic (SAP), diastolic (DAP) and mean arterial pressures (MAP). It was also verified the possible influence of the anesthetic on compensatory mechanism of acute hypovolemia. Twenty adult mongrel dogs, males and females were used. General anesthesia was induced with isoflurane at 2.5% MAC. Thereafter, orotracheal intubation was performed, and the vaporizer was calibrated to 1.5% MAC. To induce hypovolemia, a total amount of 35 mlkg-1 of blood was withdrawn from each dog. The measurements were performed before hypovolemia (M0), immediately after hypovolemia (M1), ten minutes after M1 (M2), thirty minutes after M1 (M3) and sixty minutes after M1 (M4). Numeric data were submitted to variance analysis, followed by Tukey's test, at a 5% (P<0.05) level of significance. There was reduction of electric conduction atrium-ventricular time, heart rate, cardiac and systolic index, the impedance of ventricular musculature increased, without ventricular despolarization alteration, and the isoflurane did not interfere the compensatory mechanism activation on the acute hypovolemia.
electrocardiography; hypovolemia; isoflurane; dogs
