The effects of ketamine on cardiovascular dynamics during halothane and enflurane anesthesia.

The cardiovascular effects of a single dose of ketamine administered during halothane or enflurane anesthesia were studied in 24 patients. During halothane anesthesia, ketamine caused a rapid and significant increase in arteriolar peripheral resistance (p less than 0.01) and a decrease in cardiac output, stroke volume, and systolic diastolic, and mean arterial blood pressures. Heart rate was not significantly changed. Ketamine resulted in similar, though less dramatic and slower developing, changes in patients anesthetized with enflurane. These results demonstrate that general anesthesia blocks the cardiovascular-stimulating properties of ketamine. They also indicate that ketamine has significant cardiovascular-depressant qualities when used during halothane or enflurane anesthesia.