The Journal of veterinary medical science
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Comparative Study
Rapid inhalation induction of anesthesia by halothane, enflurane, isoflurane and sevoflurane and their cardiopulmonary effects in dogs.
The rapid inhalation induction of anesthesia (RII) by mask inhalation of halothane, enflurane, isoflurane and sevoflurane at an equianesthetic concentration (2.5 MAC) was evaluated in 24 beagle dogs. The differences in movements, induction and intubation time between anesthetics were mainly associated with the differences in each blood/gas solubility. The most rapid and smoothest induction was observed by sevoflurane inhalation (209.0 +/- 44.2 sec), followed by isoflurane inhalation (285.8 +/- 34.1 sec). ⋯ These changes exceeded the physiological level just after the beginning of inhalation, however, rapidly reversed to the maintenance level (1.5 MAC) approximately 10 min after intubation. Consequently, sevoflurane seemed to be the best inhalational anesthetic for RII in dogs without significant problems in respiratory and/or cardiac functions. Isoflurane also induced rapid induction with some degree of the movements.
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Comparative Study
Clinical application of rapid inhalation induction of anesthesia using isoflurane and sevoflurane with nitrous oxide in dogs.
Clinical usefulness of rapid inhalation induction of anesthesia (RII) using 5.0 vol.% isoflurane (GOI) and sevoflurane (GOS) with N2O was evaluated in 124 canine patients. Induction times, loss of various reflexes and movement times were significantly faster in GOI group than in GOS group. ⋯ Positive correlation between body weight and degree of movements was observed in both induction groups. Thus, RII using GOI is a practically useful and safe induction modality in small- to medium-sized dogs.
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Comparative Study
Studies on the factors affecting the recording of somatosensory evoked potentials induced by tibial nerve stimulation in dogs.
Since spinal cord abnormalities are often associated with lesion in the thoracic or lumber vertebrae, examination of Somatosensory evoked potential (SEP) induced by hind limb nerve stimulation will be useful. In the experiment, scalp recorded SEP in dogs by tibial nerve stimulation was studied on the distribution, the change of latency by body size and the influence of experimental compression to the spinal cord. ⋯ In the experimental study of compression to spinal cord, dorsal compression tended to be sensitive compared to the ventral compression. This study suggested that not only increase of latency but also reduction of amplitude could occur as a result of spinal cord disorders.
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Liver blood flow was investigated in hypovolemic shock using a modified right heart bypass technique which can obtain accurate portal blood flow. Findings were similar to those previously reported: hepatic blood flow accounted for 34% of cardiac output in this study; 76% of hepatic blood flow was delivered from the portal vein and 24% from the hepatic artery. Hypovolemic shock markedly decreased total liver blood flow by a reduction in portal venous blood flow. ⋯ Development of a hepatic arterial buffer response during hypovolemic shock was confirmed by an increased ratio of hepatic arterial flow to cardiac output. Reduced total hepatic blood flow during hypovolemic shock returned to control flow by an increase in hepatic arterial flow after reperfusion. The results of this study demonstrate that compensated reactions for maintaining liver blood flow mainly due to the hepatic arterial buffer response were functioned both during hypovolemic shock and after elimination of shock.
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The selective effects od dopamine and dobutamine in various doses on liver circulation were studied in 12 mongrel dogs. Dopamine increased portal flow but decreased hepatic arterial flow markedly as infusion rate of dopamine increased. Dopamine 3 micrograms/kg/min infusion rate produced vasodilation in mesenteric vascular bed and the portal flow ratio to cardiac output was significantly increased. ⋯ These findings suggest that congestive hyperemia was not occurred in intrahepatic portal vascular system when portal flows were increased during dopamine and dobutamine infusion. The results of this study demonstrate that both dopamine and dobutamine did not produce selective increases in total liver blood flow. In addition, both agents should be safe to use to the normal liver patient; total liver blood flow did not decrease and intrahepatic congestive hyperemia was not occurred when portal flow was increased.