Search Results

You are looking at 1 - 7 of 7 items for

  • Author or Editor: Kazuto Yamashita x
  • Refine by Access: All Content x
Clear All Modify Search

Abstract

Objective—To evaluate the cardiovascular effects of total IV anesthesia with propofol (P-TIVA) or ketamine-medetomidine-propofol (KMP-TIVA) in horses.

Animals—5 Thoroughbreds.

Procedures—Horses were anesthetized twice for 4 hours, once with P-TIVA and once with KMP-TIVA. Horses were medicated with medetomidine (0.005 mg/kg, IV) and anesthetized with ketamine (2.5 mg/kg, IV) and midazolam (0.04 mg/kg, IV). After receiving a loading dose of propofol (0.5 mg/kg, IV), anesthesia was maintained with a constant rate infusion of propofol (0.22 mg/kg/min) for P-TIVA or with a constant rate infusion of propofol (0.14 mg/kg/min), ketamine (1 mg/kg/h), and medetomidine (0.00125 mg/kg/h) for KMP-TIVA. Ventilation was artificially controlled throughout anesthesia. Cardiovascular measurements were determined before medication and every 30 minutes during anesthesia, and recovery from anesthesia was scored.

Results—Cardiovascular function was maintained within acceptable limits during P-TIVA and KMP-TIVA. Heart rate ranged from 30 to 40 beats/min, and mean arterial blood pressure was > 90 mm Hg in all horses during anesthesia. Heart rate was lower in horses anesthetized with KMP-TIVA, compared with P-TIVA. Cardiac index decreased significantly, reaching minimum values (65% of baseline values) at 90 minutes during KMP-TIVA, whereas cardiac index was maintained between 80% and 90% of baseline values during P-TIVA. Stroke volume and systemic vascular resistance were similarly maintained during both methods of anesthesia. With P-TIVA, some spontaneous limb movements occurred, whereas with KMP-TIVA, no movements were observed.

Conclusions and Clinical Relevance—Cardiovascular measurements remained within acceptable values in artificially ventilated horses during P-TIVA or KMP-TIVA. Decreased cardiac output associated with KMP-TIVA was primarily the result of decreases in heart rate.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To compare the anesthetic and cardiorespiratory effects of total IV anesthesia with propofol (P-TIVA) or a ketamine-medetomidine-propofol combination (KMP-TIVA) in horses.

Design—Randomized experimental trial.

Animals—12 horses.

Procedure—Horses received medetomidine (0.005 mg/kg [0.002 mg/lb], IV). Anesthesia was induced with midazolam (0.04 mg/kg [0.018 mg/lb], IV) and ketamine (2.5 mg/kg [1.14 mg/lb], IV). All horses received a loading dose of propofol (0.5 mg/kg [0.23 mg/lb], IV), and 6 horses underwent P-TIVA (propofol infusion). Six horses underwent KMP-TIVA (ketamine [1 mg/kg/h {0.45 mg/lb/h}] and medetomidine [0.00125 mg/kg/h {0.0006 mg/lb/h}] infusion; the rate of propofol infusion was adjusted to maintain anesthesia). Arterial blood pressure and heart rate were monitored. Qualities of anesthetic induction, transition to TIVA, and maintenance of and recovery from anesthesia were evaluated.

Results—Administration of KMP IV provided satisfactory anesthesia in horses. Compared with the P-TIVA group, the propofol infusion rate was significantly less in horses undergoing KMP-TIVA (0.14 ± 0.02 mg/kg/min [0.064 ± 0.009 mg/lb/min] vs 0.22 ± 0.03 mg/kg/min [0.1 ± 0.014 mg/lb/min]). In the KMP-TIVA and P-TIVA groups, anesthesia time was 115 ± 17 minutes and 112 ± 11 minutes, respectively, and heart rate and arterial blood pressure were maintained within acceptable limits. There was no significant difference in time to standing after cessation of anesthesia between groups. Recovery from KMP-TIVA and P-TIVA was considered good and satisfactory, respectively.

Conclusions and Clinical Relevance—In horses, KMP-TIVA and P-TIVA provided clinically useful anesthesia; the ketamine-medetomidine infusion provided a sparing effect on propofol requirement for maintaining anesthesia.

Full access
in Journal of the American Veterinary Medical Association

SUMMARY

Ceruloplasmin (Cp) was isolated from fresh equine plasma by precipitation, cellulose chromatography, and improved ion-exchange chromatography. Purified equine Cp is a glycoprotein having a molecular weight of approximately 115,000. In electrophoresis, equine Cp migrated to the α1-globulin region, its isoelectric point was about 4.15 and consisted of about 890 amino acid residues.

Serum Cp concentration was measured by use of the single radial immunodiffusion method. In clinically normal horses, the mean (± sd) serum Cp concentration of newborn foals was 2.87 ± 0.40 mg/ml and that of 3-month-old foals was 5.02 ± 0.92 mg/ml, which was similar to the adult value. It reached a peak of 6.06 ± 0.74 mg/ml in 2-year-old horses. The Cp concentration in mares was not statistically different for the perinatal period, but it decreased immediately before and after delivery.

Concentration of Cp increased at 6 days after im administration of turpentine oil, castration, or jejunojejunostomy in adult horses, and increased to peak values twice as high as baseline values at 7 to 14 days, returning to baseline values at 28 days after treatment.

We concluded that equine serum Cp is an acute-phase reactive protein increased in the intermediary or later phase of acute inflammation.

Free access
in American Journal of Veterinary Research

Abstract

Objective—To evaluate effects of infusion of guaifenesin, ketamine, and medetomidine in combination with inhalation of sevoflurane versus inhalation of sevoflurane alone for anesthesia of horses.

Design—Randomized clinical trial.

Animals—40 horses.

Procedure—Horses were premedicated with xylazine and anesthetized with diazepam and ketamine. Anesthesia was maintained by infusion of guaifenesin, ketamine, and medetomidine and inhalation of sevoflurane (20 horses) or by inhalation of sevoflurane (20 horses). A surgical plane of anesthesia was maintained by controlling the inhaled concentration of sevoflurane. Sodium pentothal was administered as necessary to prevent movement in response to surgical stimulation. Hypotension was treated with dobutamine; hypoxemia and hypercarbia were treated with intermittent positive- pressure ventilation. The quality of anesthetic induction, maintenance, and recovery and the quality of the transition to inhalation anesthesia were scored.

Results—The delivered concentration of sevoflurane (ie, the vaporizer dial setting) was significantly lower and the quality of transition to inhalation anesthesia and of anesthetic maintenance were significantly better in horses that received the guaifenesin-ketamine-medetomidine infusion than in horses that did not. Five horses, all of which received sevoflurane alone, required administration of pentothal. Recovery time and quality of recovery were not significantly different between groups, but horses that received the guaifenesin-ketamine-medetomidine infusion required fewer attempts to stand.

Conclusions and Clinical Relevance—Results suggest that in horses, the combination of a guaifenesin-ketamine- medetomidine infusion and inhalation of sevoflurane resulted in better transition and maintenance phases while improving cardiovascular function and reducing the number of attempts needed to stand after the completion of anesthesia, compared with inhalation of sevoflurane. (J Am Vet Med Assoc 2002;221:1150–1155)

Full access
in Journal of the American Veterinary Medical Association

SUMMARY

Marked differences in bone marrow cellularity were observed between cattle affected with leukocyte adhesion deficiency (lad) and control cattle. The number of nucleated cells in bone marrow was 2.9 to 8.8 times higher in cattle affected with lad, compared with controls. The myeloid-to-erythroid ratio of bone marrow from 3 cattle affected with lad ranged from 2.4 to 12. Deficient CD18 expression on neutrophils isolated from bone marrow of cattle with lad was clearly detected by flow cytometric analysis. Neutrophils from bone marrow of cattle affected with lad appeared round and not flat, after adherence to plastic wells under agarose, whereas neutrophils from bone marrow of clinically normal cattle were firmly spread on the surface of plastic wells. In the chemotaxis under-agarose assay, many pseudopodia were detected on bone marrow neutrophils from clinically normal cattle, but were not detected on bone marrow neutrophils from cattle with lad. Activities of chemotactic movements and phagocytosis of neutrophils isolated from bone marrow of cattle affected with lad were documented to be severely impaired.

Free access
in American Journal of Veterinary Research

Summary

Equine α1-acid glycoprotein (α1 ag) was isolated from equine serum by successive ammonium precipitation, anion- and cation-exchange chromatographies, and gel filtration. Purified equine α1 ag had a molecular weight of 46,000 ± 1,000, and contained 31.4% carbohydrate. Gel isoelectric focusing revealed an isoelectric point range of 2.8 to 3.7. With immunoelectrophoresis, it was found that α1 ag migrated to the α1-globulin region.

Single radial immunodiffusion was used for quantitative measurement of α1 ag in equine serum. In clinically normal foals, serum α1 ag was undetectable (≤ 20 ng/ml) in ≤ 7-day-old foals, but was detected by 14 days. The α1 ag concentration (mean ± sd) increased to reach mean adult values of 99.23 ± 26.90 μg/ml by 1 year of age. The α1 ag concentration in pregnant mares decreased at 2 to 3 months before parturition, then gradually increased until 1 day after parturition, when a brief decrease was observed. The concentration increased again at 2 weeks after foaling, then a decrease was observed, after which the α1 ag concentration increased again by 2 to 4 months after parturition.

The concentration of serum α1 ag quickly rose to peak values 2 to 3 days after castration and jejunojejunostomy in adult horses, returning to baseline values by 14 to 28 days after surgery. The α1 ag was concluded to be an acute-phase reactive protein in horses.

Free access
in American Journal of Veterinary Research

Abstract

Objective—To compare the analgesic and cardiopulmonary effects of medetomidine and xylazine when used for premedication of horses undergoing general anesthesia.

Design—Randomized clinical trial.

Animals—40 horses.

Procedure—Twenty horses were premedicated with medetomidine (10 µg/kg [4.5 µg/lb], IM) and the other 20 were premedicated with xylazine (2 mg/kg [0.9 mg/kg], IM). Horses were then anesthetized with a combination of guaifenesin and ketamine; anesthesia was maintained with halothane. Additional doses of medetomidine or xylazine were given if horses were not sufficiently sedated at the time of anesthetic induction. After induction of anesthesia, sodium pentothal was administered as necessary to prevent limb movements. Hypotension was treated with dobutamine; hypoventilation and hypoxemia were treated with intermittent positive-pressure ventilation. The quality of anesthetic induction, maintenance, and recovery and the quality of the transition to inhalation anesthesia were scored.

Results—Scores for the quality of the transition to inhalation anesthesia were significantly higher for horses premedicated with medetomidine than for horses premedicated with xylazine. However, other scores, recovery times, and numbers of attempts needed to achieve sternal recumbency and to stand were not significantly different between groups.

Conclusions and Clinical Relevance—Results suggest that medetomidine is suitable for premedication of horses undergoing general anesthesia. Analgesic and cardiopulmonary effects of medetomidine were similar to those of xylazine, except that the transition to inhalation anesthesia was smoother when horses were premedicated with medetomidine, rather than xylazine. (J Am Vet Med Assoc 2002;221:1144–1149)

Full access
in Journal of the American Veterinary Medical Association