Topic:Anesthesia
Anesthesia in horses involves the administration of drugs to induce a temporary loss of sensation or consciousness, facilitating surgical procedures and other medical interventions. This complex process requires a deep understanding of equine physiology and pharmacology to ensure the safety and well-being of the animal. Anesthesia in horses can be challenging due to their size, temperament, and unique anatomical and physiological characteristics. Common anesthetic agents used in equine practice include inhalants like isoflurane and sevoflurane, as well as injectable drugs such as ketamine and xylazine. The management of anesthesia in horses also involves careful monitoring of vital signs and the use of supportive measures to prevent complications such as hypotension, hypoventilation, and post-anesthetic myopathy. This page compiles peer-reviewed research studies and scholarly articles that explore the techniques, advancements, and clinical outcomes associated with anesthesia in equine medicine.
Succinylcholine infusion associated with hyperthermia in ponies anesthetized with halothane. Succinylcholine was administered by infusion to halothane-anesthetized ponies to determine dosage requirements for surgical relaxation up to 3 hours' duration. This was not possible to do, since 4 of 6 ponies studied developed severe reactions characterized by prolonged muscle fasciculations after the initial succinylcholine dose, muscle rigidity, hyperthermia, hypercapnia, tachycardia, increasing pulse pressure, and metabolic acidosis. The reactions resembled those associated with malignant hyperthermia, a disease recognized in persons and swine. Two ponies showed signs of the phase II or des...
Continuous caudal epidural and subarachnoid anesthesia in mares: a comparative study. A new technique for producing continuous caudal epidural analgesia (CEA) and caudal subarachnoid analgesia (CSA) in adult horses (mares) without causing loss of pelvic limb function is described. A modified 17-gauge Huber-point directional needle was used to place a catheter with stylet into either the epidural or subarachnoid space at the lumbosacral intervertebral junction. The catheter was positioned at either the midsacral (S2-3) subarachnoid space or caudal portion of the sacral (S-3 to S-5) epidural space in 7 mares. The position of the catheter was confirmed radiographically. A 2% solut...
Segmental epidural and subarachnoid analgesia in conscious horses: a comparative study. Six adult horses were used to compare the effects of segmental epidural analgesia (SEA) and segmental subarachnoid analgesia (SSA). A 17-gauge Huber point directional needle was used to place a catheter with stylet into the epidural space or the subarachnoid space at the lumbosacral intervertebral junction and to catheterize the thoracolumbar epidural or subarachnoid space. The position of the catheter was confirmed radiographically. A 2% solution of mepivacaine hydrochloride was used at average doses of 80 mg (4 ml) to produce SEA and 30 mg (1.5 ml) to produce SSA. Onset of analgesia in respo...
[An inventory of the castration of stallions based on a survey among Dutch veterinarians]. To gain an insight into the procedures adopted in castrating stallions in the Netherlands, a questionnaire was sent to 670 Dutch veterinary practitioners. The 176 veterinary practitioners who replied performed 1850 castrations. Castration of the recumbent horse was preferred by 88 per cent of the veterinary surgeons. Fifty per cent preferred the open method of castration and 44 per cent the half-closed technique. A local anaesthetic was given by 65 per cent of the practitioners; 84 per cent administered antibiotics in an attempt to prevent wound infection. Postoperative complications were obse...
A new analgesic drug combination in the horse. A xylazine and butorphanol drug combination produced minimal and transient hemodynamic effects and no significant respiratory depression when administered to 6 healthy horses. Combining xylazine and butorphanol produced a synergistic analgesic effect and provided good chemical restraint for a standing surgical procedure.
Cytology of equine cerebrospinal fluid. The cytology of cerebrospinal fluid samples from horses is described. The samples were obtained from 24 normal horses, 35 horses with axonal degeneration and/or spinal cord compression, 29 horses with encephalomyelitis, 14 horses with other lesions of the nervous system, and eight horses with signs of neurologic dysfunction of undetermined origin. (Three of the latter were suspected botulinum intoxications.) Fluid was aspirated from the atlanto-occipital space following general anesthesia or immediately after a lethal dose of barbiturate. In two horses, fluid also was aspirated from the lumbos...
Malignant hyperthermia-like reactions in three anesthetized horses. Problems encountered during halothane anesthesia in 3 horses included increasing rectal temperature, muscle rigidity or movement during anesthesia, irregular breathing patterns, and difficulty in stabilizing blood pressure. One horse had prolonged muscle fasciculations and failure to relax after administration of succinylcholine in addition to halothane. That horse developed severe, bilateral myositis of the triceps, lumbar, and gluteal muscles. Problems encountered were similar to those caused by the disease known as malignant hyperthermia.
Decreased tear production associated with general anesthesia in the horse. Schirmer I tear tests were conducted on 14 horses. The test was performed before and after IV administration of xylazine hydrochloride, during maintenance anesthesia with halothane in oxygen, and 3 hours after discontinuation of anesthesia. Xylazine hydrochloride did not decrease tear production from the mean base-line value of 23.94 +/- 5.23 mm/min after its IV administration. Tear production was decreased to mean values of 15.57 +/- 4.29 mm/min at 30 minutes and 13.84 +/- 4.25 mm/min at 60 minutes during the maintenance of halothane anesthesia. Three hours after anesthesia was discontinued, ...
Segmental thoracolumbar spinal (subarachnoid) analgesia in conscious horses. A new technique for producing segmental subarachnoid analgesia in adult horses without causing complete loss of locomotor control is described. A 17-gauge Huber point (Tuohy) needle was used to place a catheter with a stylet into the subarachnoid space at the lumbosacral intervertebral space in 13 adult horses (weighing 500 +/- 60 kg, representing both sexes) and to advance the catheter craniad to the thoracolumbar area. The position of the catheter was confirmed radiographically. A 2% mepivacaine hydrochloride solution (1.5 ml, 30 mg) was injected through the catheter at a rate of 0.5 ml/60 s...
Use of a demand valve for postoperative administration of oxygen to horses. The study examines the efficiency of a demand valve in administering oxygen to horses post-anesthesia. It finds that the use of the demand valve corrects potentially dangerous levels of low […]
Radiographic characterization of diaphragmatic excursion in halothane-anesthetized ponies: spontaneous and controlled ventilation systems. A radiograph technique for identification of diaphragmatic segments and quantitation of their contribution to total diaphragmatic function was developed. five anesthetized ponies were studied on 3 separate occasions. Studies were made of the ponies in left lateral recumbency at 2 anesthetic levels (1 and 2 minimal alveolar anesthetic concentrations; halothane) and under spontaneous and controlled ventilation systems. General pattern of diaphragmatic displacement was unchanged by increased depth of anesthesia. Controlled ventilation altered the pattern of diaphragmatic displacement. Diaphragmat...
Effects of dexamethasone on endotoxin shock in the anesthetized pony: hematologic, blood gas, and coagulation changes. The effects of dexamethasone (1 mg/kg of body weight) on hematologic, blood gas, and blood coagulation values in anesthetized ponies during endotoxin-induced shock were evaluated. Fifteen ponies were assigned to 3 groups of 5 ponies each: group 1, anesthetized nontreated and dexamethasone-treated controls; group 2, endotoxin, nontreated; group 3, endotoxin, dexamethasone treated. The hematologic changes in this endotoxin shock model included leukopenia and hemoconcentration. Significant hematologic effects were not seen in ponies after administration of dexamethasone. However, dexamethasone tr...
Forelimb tic in a horse. An 18-month-old male Quarter Horse was referred for evaluation of a tic that had started after injury to the right forelimb 4 weeks earlier. The right forelimb appeared paretic and had constant regular twitches of variable intensity that were usually sufficiently forceful to move the trunk, neck, and head. The horse frequently threw the limb forward. The twitch persisted during sleep but disappeared during general anesthesia and following sedation with xylazine. It was unaffected by acetylpromazine, diphenylhydantoin, diazepam, carbamazepine, trimethadione, procainamide, quinidine, propranolol...
Radiographic examination of the equine stifle. A radiographic technique is described for the equine stifle joint with the horse in the standing position or under general anaesthesia. The method with the animal anaesthetised in the dorsal recumbency and the leg extended was preferred because it gave greater flexibility with a better range of views and greatly reduced the safety hazards. In the standing position a useful practical tip for the lateral view was to raise and extent the limb caudally. This provides some flexion and ventral movement of the stifle allowing improved access for the cassette, a more accurate lateral view of the joint...