Systemic and Coronary Haemodynamic Effects of Ketamine in Intact Anaesthetized and Un Anaesthetized Dogs

Abstract

Ten intact anaesthetized dogs breathing room air spontaneously (Group A) were compared with ten artificially ventilated dogs (Group B). All were given a bolus of ketamine 2 mg/kg followed by a 20-min infusion of ketamine 0.1 mg/kg/min. In Group A, coronary sinus blood flow, measured with a thermodilution flowmeter, increased by 90% while coronary vascular resistance decreased by 28% and coronary sinus oxygen content decreased by 27%. Heart rate increased by 47%, and arterial pressure by 9%. Cardiac output, calculated by the dye dilution method, increased by 29%, while the left ventricular work index decreased by 50%. Minute ventilation rate decreased by 55%. The Group B dogs were studied as described above, except that they were artificially ventilated. The haemodynamic ahanges were less in Group B, possibly because of improved arterial oxygenation. Heart rate increased by 24%, cardiac output by 21% and arterial pressure by 2%. The coronary sinus blood flow increased by 12% while coronary vascular resistance decreased by 11%. Coronary sinus oxygen concentration decreased by 15%. Five unanaesthetized dogs with electromagnetic flowmeter probes chronically implanted on the aorta and circumflex coronary artery, and an indwelling arterial catheter were studied before, during and after the intravenous administration of ketamine 2, 4, and 8 mg/kg. A dose of 8 mg/kg produced increases in cardiac output, heart rate and arterial pressure of 21%, 44% and 24%, respectively, while coronary blood flow increased 47%. We conclude that, in healthy dogs, ketamine produces an increase in heart rate and cardiac work. A significant increase in coronary blood flow appears to be insufficient to meet the metabolic demands of the myocardium, as the coronary sinus oxygen content decreased.

Clinical practice guideline for emergency department ketamine dissociative sedation in children

“…It is unclear whether the increased coronary perfusion associated with this hyperdynamic state parallels increases in oxygen demand. 2,51,[68][69][70] Although ketamine has been widely administered to elderly patients in the developing world, 57,71 the baseline incidence of coronary artery disease in these populations is substantially lower than that in developed countries, and safety in this setting cannot be extrapolated.…”

Early Hemodynamic Changes during Uncontrolled Intra-Abdominal Bleeding

“…Ketamine was chosen to reduce the depressive effect of general anesthesia on the hemodynamic results [4]. In experimental animals, ketamine increases heart rate and cardiac work [5] which might result in larger blood losses compared to the use of other types of general anesthesia in uncontrolled bleeding [6].…”

Effects of xylazine/ketamine on cardiac function and serum ionised calcium in horses

“…Alveolar ventilation decreases, however, and respiratory acidosis may result (Folts et al 1975). This did not occur in our study and was minor and short-lived in a previous study assessing xylazineketamine effects in horses .…”