Blood pressure and pulse rate responses to extubation with and without prior topical tracheal anaesthesia.

The results of this study demonstrate that 60 mg of lidocaine sprayed down the tracheal tube before extubation and 40 mg sprayed down the tracheal tube before extubation and 40 mg sprayed down during tracheal tube removal prevents increases in blood pressure and pulse rate during and after extubation. The data suggest that this manoeuvre should be of advantage to patients with coronary artery disease who may not be able to tolerate the increased cardiac dynamics which usually accompany extubation.

The cardiovascular effects of diazepam and of diazepam and pancuronium during fentanyl and oxygen anaesthesia.

The cardiovascular effects of diazepam 0.5 and 1.0 mg/kg and diazepam with pancuronium 0.1 mg/kg after fentanyl 0.5 mg/kg were determined in thirteen dogs premedicated with atropine. Fentanyl produced significant reductions in heart rate, cardiac ouptut and arterial blood pressure. Administration of 0.5 mg/kg of diazepam after fentanyl did not significantly alter stroke volume, arterial blood pressure or peripheral vascular resistance but did increase heart rate and cardiac output. Additional diazepam did not further change the heart rate, but did reduce stroke volume, cardiac output, arterial blood pressure and peripheral vascular resistance. Administration of pancuronium after fentanyl and diazepam produced marked elevations in heart rate, cardiac output and arterial blood pressure. There was no difference in mean heart rate and cardiac output when values prior to fentanyl and those obtained three minutes following pancuronium were compared. These data demonstrate that large doses of fentanyl decrease heart rate, cardiac these changes can be partially reversed with diazepam 0.5 mg/kg and completely antagonized with pancuronium 0.1 mg/kg.

Cardiovascular dynamics after large doses of fentanyl and fentanyl plus N2O in the dog.

The effects of large doses of fentanyl (0.05 to 2 mg/kg) and fentanyl plus N2O on cardiovascular dynamics were determined in 10 unpremedicated dogs breathing 100% O2. Using computer analysis of the central aortic pulsepressure curve, stroke volume (SV), cardiac output, heart rate (HR), peripheral vascular resistance (PVR), and systolic, diastolic, and mean arterial blood pressures (BP) were determined while fentanyl was being given at a rate of 0.3 to 0.44 mg/min. Fentanyl caused a dose-related decrease in HR, which was significant at 0.05 mg/kg. Cardiac output, PVR, and systolic, diastolic, and mean arterial BP were also decreased and SV increased. The latter changes became significant at 0.1 mg/kg for diastolic BP; 0.15 mg/kg for cardiac output and mean BP; 0.25 mg/kg for sv and systolic BP; and at 1.25 mg/kg for peripheral vascular resistance. Addition of N2O after fentanyl did not significantly change any parameter, although SV, cardiac output, and HR were usually increased and PVR decreased. These data demonstrate that, while large doses of fentanyl or fentanyl plus N2O do alter cardiovascular dynamics in dogs, the changes appear to be less profound than those produced by equianalgesic doses of morphine. Our findings suggest that large doses of fentanyl-O2 may be an attractive alternative to morphine-O2 anethesia in critically ill patients.

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.

Effects of anesthetic doses of morphine on renal function in the dog.

Renal effects of anesthetic doses of morphine (2 mg./kg.) administered intravenously (I.V.) were determined in 15 mongrel dogs before and after addition of 50 percent nitrous oxide (N2O). Morphine significantly increased urine osmolarity and decreased urine output, free-water clearance, and arterial blood pressure, but did not affect inulin or para-aminohippurate (PAH) clearances. Addition of N2O did not significantly change arterial blood pressure and inulin clearance but did decrease urine osmolarity and osmolar and PAH clearances. These data demonstrate that, in contrast to man, anesthetic doses of morphine have significant antidiuretic properties in the dog.