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.
Cardiopulmonary effects of oral trazodone administration prior to isoflurane anesthesia in healthy horses. To determine the cardiopulmonary effects of oral trazodone before isoflurane anesthesia in systemically healthy horses. Unassigned: 12 horses donated for euthanasia (from August 2022 through June 2023) due to conditions unrelated to the cardiovascular system were included in this prospective, randomized, controlled trial. Horses were assigned to receive oral trazodone (6 mg/kg; n = 7) or corn syrup (n = 5) 1 hour before xylazine (1 mg/kg, IV) sedation, ketamine (2.2 mg/kg, IV) and propofol (0.7 mg/kg, IV) induction, and anesthetic maintenance with inhaled isoflurane (target 1.6% expired) for 7...
A Retrospective Study on Pre- and Intraoperative Predictors on the Recovery Quality of Horses After General Anesthesia. Equine anesthesia is related to high morbidity and mortality rates and recent studies suggested that the period of recovery remains the phase associated with the greatest risk of mortality in horses. Intraoperative hypotension, hypoxemia, and hypercapnia are recognized as potential determinants of recovery quality. This study, conducted at the Equine University Hospital of Liege, aimed to explore how these factors influence recovery outcomes and compare complications between non-emergency and emergency procedures. We analyzed data from 1057 horses, with a mean weight of 498 kg (ranging from 15...
Intranasal Dental Repulsion of a Displaced Cheek Tooth in an Arabian Filly. This case report documents an unusual cheek tooth (CT) displacement in a 3-year-old Arabian filly. The horse was referred to the clinic for loss of appetite and right-sided facial deformity. At admission, an oral inspection was performed, followed by a dental radiographic examination. The radiographs showed a very oblique vertical angulation (135°) of the CT 106 compared to the other premolars (107 and 108 CTs) (40°). In consideration of the clinical and radiographic findings, surgical extraction of the 106 CT was indicated. Due to the unique positioning of the displaced tooth, traditional e...
Dobutamine improves haemodynamics and oxygen delivery in standing and isoflurane-anaesthetised horses. Dobutamine is a first-line therapy for hypotension in anaesthetised horses, but the effects on haemodynamic parameters in standing and anaesthetised horses are not well studied. Objective: To investigate the effects of dobutamine in escalating dosages on haemodynamic performance in awake and anaesthetised horses. Methods: Randomised cross-over experimental study. Methods: Six healthy adult horses were enrolled, including both standing and isoflurane-anaesthetised experiments with 1-week washout. Heart rate, mean arterial pressure (MAP), central venous pressure, pulmonary arterial pressure, and...
Return of spontaneous circulation after cardiopulmonary arrest in an adult horse recovering from anaesthesia. This report describes successful cardiopulmonary resuscitation of a healthy, 525 kg, 8 years 9 months-old Quarter horse gelding. After successful pelvic limb orthopaedic surgery to excise a metatarsal bone under general anaesthesia, with the horse in left lateral recumbency, the horse was hoisted into recovery. After the horse was positioned in recovery, a routine cardiac check by thoracic auscultation was performed. Cardiopulmonary arrest (CPA) was identified by absence of cardiac sounds and pulse, as evaluated by digital palpation of the facial artery, absence of the right palpebral reflex, ...
Systemic, hemodynamic and neurological effects of caudal epidural administration of Neosaxitoxin in horses. The present study was conducted to evaluate the safety and the long-lasting anesthetic properties of Neosaxitoxin (NeoSTX) when injected into the intercoccygeal space in standing horses. A group of eighteen (n = 18) healthy client-owned mature crossbreed horses were enrolled in this study. Caudal epidural injection was ascertained by two methods, the "hanging drop" technique and radiographs. Horses were allocated into three groups (n = 6) each group receiving different dosages of NeoSTX. To assess the onset of action and duration of anesthesia, six horses received 20 μg in 2 mL, six 20Â...
Evaluation of Spectral Entropy Monitor with Different Concentrations of Isoflurane in Horses. Spectral entropy and bispectral index (BIS) can differentiate between conscious and unconscious levels in horses. This study aimed to determine whether spectral entropy and BIS parameters can distinguish between different end-tidal isoflurane concentrations (EtIso, %), and whether these parameters change when a nociceptive stimulus is applied. Ten clinically healthy horses were anaesthetized using xylazine, diazepam, ketamine, and isoflurane. The following parameters were monitored: EtIso, response entropy (RE), state entropy (SE), RE-SE difference, BIS, and electromyography (EMG). Three EtIso...
Prevalence and degree of orotracheal intubation-related tracheal lesions in horses. Orotracheal intubation is commonly performed for inhalation anaesthesia in horses to ensure safe and reliable administration of volatile anaesthetics and to secure the airways. In human and equine medicine, the occurrence of intubation-associated complications has been described, which can range from mild mucosal irritation to severe necrosis. However, there are only sparse descriptions of mucosal alterations and the course of healing after elective surgery in horses. Objective: To investigate the prevalence and severity of tracheal lesions following endotracheal intubation associated with gen...
Analgesic and Gastrointestinal Effects of Morphine in Equines. Morphine has significant clinical and analgesic effects in horses, but its impact on the gastrointestinal tract requires further understanding. This study assessed the analgesic and gastrointestinal effects of morphine in horses undergoing elective orchiectomy in the quadrupedal position. Thirty uncastrated male horses were randomly assigned to three groups: orchiectomy without morphine and sedation protocol (OSM), orchiectomy with morphine and sedation protocol (OM), and administration of morphine alone in the absence of orchiectomy (M). The anesthetic protocol involved acepromazine (0.05 mg/...
The Use of an Air-Inflated Pillow for Assisted Recovery After General Anaesthesia in Horses: A Preliminary Study. Different assisted recovery techniques have been developed to enhance the safety and quality of equine recoveries. This case series evaluates the recovery of horses using an air-inflated pillow (Equi-lift®). With owner consent, the following data were collected from 19 horses undergoing open castration and 21 horses where a difficult recovery was anticipated: age, bodyweight, procedure, anaesthetic protocol, time required for proper positioning in the Equi-lift®, time to extubation, time to standing, number of attempts to stand, number of stimuli, behaviour during recumbency/first attempts, ...
Evaluation of the Effect of Intravenous Mannitol and Hypertonic Saline on Intraocular Pressure and Biometry Parameters in Anesthetized Horses With Experimentally Increased Intracranial Pressure. To evaluate the effect of intravenous mannitol and hypertonic saline (HS) on intraocular pressure (IOP) and biometry parameters of horses with elevated intracranial pressure (ICP). Methods: Seven horses with normal ophthalmic exams were anesthetized and placed in lateral recumbency. A subarachnoid transducer was placed, and the head was lowered until ICP measured 40 mmHg +/- 2 mmHg. Five intravenous boluses of mannitol 20% (0.4 g/kg) or HS 7.2% (1 mL/kg) were administered, each 15 min apart. A 2-day washout period ensued, and the procedure was repeated with the other hyperosmotic age...
Effect of an adjustable ceiling to prevent premature rising attempts after general anesthesia in healthy ponies and horses: A pilot study. This study aimed to assess and compare the recovery of ponies and horses following general anesthesia in two different settings: a recovery box with an inflexible, adjustable ceiling, and free recovery without restraints. Our primary objective was to evaluate the effect of adjustable ceilings on the prevention of premature attempts to rise during recovery. The secondary aim was to compare the physiological stress indicators during recovery. Methods: Prospective, randomized, experimental study. Methods: Six healthy ponies and 10 healthy horses. Methods: This study used a crossover design with t...
Examining the arrhythmogenicity of dobutamine when used in conjunction with isoflurane in horses: A retrospective study at a single university teaching hospital. Dobutamine is used to treat hypotension in isoflurane-anaesthetised horses but may produce arrhythmias. Halothane is a volatile anaesthetic that was, historically, widely used in horses, but in one study, 56 of 200 halothane-anaesthetised horses (28%) developed arrhythmias after dobutamine administration. Although isoflurane has largely replaced halothane, it is unknown how isoflurane and dobutamine interact in the development of arrhythmias. Methods: The medical records of horses undergoing general anaesthesia at the University of Georgia Veterinary Teaching Hospital in 2015 were reviewed ret...
Changes in microcirculation variables in an acute endotoxaemic equine model. Microcirculation is the essential link between macrocirculation and cellular metabolism. Objective: To test our hypotheses that microcirculation variables will show a heterogeneous flow pattern during experimental endotoxaemia, and that fluid therapy and noradrenaline (NA) infusion will normalise altered microcirculation variables. Methods: In vivo experiments. Methods: Six healthy adult horses were anaesthetised with dexmedetomidine, ketamine, and diazepam and were mechanically ventilated under isoflurane anaesthesia. Endotoxaemia was induced with 30 ng kg Escherichia coli lipopolysacchar...
Retrospective evaluation of the effect of xylazine infusion on survival to discharge in horses undergoing exploratory laparotomy for colic. To determine the influence of xylazine infusion on survival to discharge and describe the associated intraoperative requirement for isoflurane, use of positive inotropes and vasopressors, and recovery time in horses undergoing exploratory laparotomy. Methods: Retrospective cohort study. Methods: A total of 352 horses. Methods: Medical records of horses undergoing anesthesia for exploratory laparotomy from January 2018 to December 2023 were reviewed. Data collected included survival to discharge, results of diagnostic tests, end tidal isoflurane concentration (FE'Iso), use of vasopressors/inotr...
Evaluation of equine perineural anesthesia simulators with integrated success control for veterinary education. The skills necessary to perform diagnostic perineural anesthesia in equids belongs to one of the Day One Competences of a veterinarian, so every veterinary graduate should be able to perform them correctly. For logistical, hygienic and ethical reasons, practical exercises on cadaver limbs are not accessible to all students. Two equine distal limb simulators were developed and evaluated as an additional instructional tool to train the required skills. Both simulators were designed and built with an integrated success control, with Simulator I (S1) designed to be a simplified anatomical model an...
Effect of rapid and slow intravenous injection of sodium penicillin on arterial blood pressure in isoflurane-anesthetized horses during surgery. To determine the effects of rapid (1 minute) and slow (10 minutes) intravenous (IV) injection of sodium penicillin on arterial blood pressure in anesthetized horses. Methods: Prospective randomized clinical trial. Methods: A group of 29 client-owned horses of various breeds, 1-20 years old, with body masses of 360-710 kg. Methods: General anesthesia was induced with a variety of anesthetic protocols and maintained with isoflurane under mechanical ventilation, with hourly doses of IV lidocaine and an infusion of dexmedetomidine. Horses were administered IV intraoperative penicillin every 2 hour...
Effects of anesthetic protocol, procedure, and recovery stall and interval on the quality of recovery in repeatedly anesthetized horses. The objective of this prospective study was to investigate whether repeated consecutive general anesthesia in horses undergoing 2 different anesthetic protocols could lead to improved recovery scores. Six healthy female Standardbred horses (453 ± 57 kg; 6.5 ± 4.2 y old) underwent 4 anesthetic protocols over 12 to 13 wk. Procedures 1 and 4 were arthroscopic surgeries [induction: xylazine, diazepam, and ketamine; and maintenance: Fe'Isoflurane (1.1%), lidocaine (2 mg/kg body weight [BW], 50 to 100 μg/min per kg BW), dexmedetomidine (2.5 μg/h per kg BW)]. Procedures 2 and 3 were preparation f...
Anesthesia and Myopathies of Horses. Pre-existing muscle disorders in horses can often be subtle and may only become evident during or after anesthesia. Advancements in veterinary medicine, along with increased knowledge and research in this field, help minimize anesthesia-related problems. Adequate preanesthesia assessment, early disease diagnosis, and proper management are crucial in minimizing risks to the neuromuscular system during general anesthesia.
Pharmacodynamics and pharmacokinetics of rocuronium in sevoflurane-anesthetized Thoroughbred horses. To investigate the pharmacodynamics and pharmacokinetics of rocuronium administered by bolus injection to sevoflurane-anesthetized horses. Methods: Prospective, experimental, crossover study. Methods: Five healthy adult Thoroughbred horses (body mass 368-470 kg, three females and two males). Methods: Each horse was anesthetized twice with sevoflurane and assigned to be administered rocuronium bromide intravenously: 0.2 mg kg (R02) or 0.4 mg kg (R04). There was a minimum 2 week washout period between experiments. During anesthesia, the peroneal nerve was stimulated (train-of-four) and neuromusc...
Comparison of end-to-side versus side-to-side jejunocecostomy in horses. To compare end-to-side (ES) and side-to-side (SS) jejunocecostomy (JC) in healthy horses. Methods: Experimental study in vivo. Methods: A total of 14 healthy adult horses underwent ventral midline celiotomy, a resection, and either an ES (n = 7) or stapled SS (n = 7) JC. Methods: Surgical times and the external lengths of completed anastomoses were measured. Physical examinations and pain scoring were performed every 6 h for 5 days, then once daily until euthanasia and necropsy 28 days postoperatively. Results: The anastomosis was completed more rapidly (p < .002) with the SS...
How to perform a transtracheal aspirate in horses for diagnosis of lower respiratory tract disease. To describe indications for and demonstrate the technique to perform a transtracheal aspirate in horses. Transtracheal aspirate is indicated to collect samples for cytology and bacteriologic culture in cases of suspected pneumonia or other lower respiratory tract disease. Methods: 1 healthy university-owned horse was used for demonstration purposes. Images of clinical case samples from the University of Illinois Veterinary Teaching Hospital are shown. Methods: The horse is restrained and sedated with detomidine or xylazine to facilitate restraint and butorphanol to minimize coughing. The ventr...
Effect of Bio-Electro-Magnetic-Energy-Regulation (BEMER) Horse Therapy on Cardiopulmonary Function and Recovery Quality After Isoflurane Anesthesia in 100 Horses Subjected to Pars-Plana Vitrectomy: An Investigator-Blinded Clinical Study. The use of Bio-Electro-Magnetic-Energy-Regulation (BEMER) therapy during general anesthesia has not previously been reported in horses. This randomized, investigator-blinded, placebo-controlled trial evaluates equine cardiopulmonary function and recovery quality after BEMER therapy application for 15 min in 100 horses during general anesthesia using isoflurane for pars-plana vitrectomy surgery as treatment for recurrent uveitis. Visually identical blankets were used in the two groups (1:1 ratio), one with a functional BEMER module and the other with a placebo module. Arterial blood pressure, b...
Electrochemotherapy with bleomycin for bilateral ocular squamous cell carcinoma in a horse. To describe the procedure and outcome of electrochemotherapy (ECT) with bleomycin as a first-line treatment for bilateral ocular surface squamous neoplasia (OSSN) in the eye of a horse. Methods: A client-owned 5-year-old Haflinger gelding with limbal-conjunctival squamous cell carcinoma. Methods: During general and local anesthesia, injection of bleomycin in the ocular tumor was followed by electroporation, applied with a 15 mm needle electrode, needles held parallel to the ocular surface. Results: Treatment with ECT resulted in therapeutic electric pulses and complete tumor response with no...
Electrochemotherapy with bleomycin for bilateral ocular squamous cell carcinoma in a horse. To describe the procedure and outcome of electrochemotherapy (ECT) with bleomycin as a first-line treatment for bilateral ocular surface squamous neoplasia (OSSN) in the eye of a horse. Methods: A client-owned 5-year-old Haflinger gelding with limbal-conjunctival squamous cell carcinoma. Methods: During general and local anesthesia, injection of bleomycin in the ocular tumor was followed by electroporation, applied with a 15 mm needle electrode, needles held parallel to the ocular surface. Results: Treatment with ECT resulted in therapeutic electric pulses and complete tumor response with no...
Successful management of two horses with suspected pulmonary haemorrhage in recovery from general anaesthesia. A 24 year old warmblood mare (case 1) and a 12 year old Holsteiner gelding (case 2) were anaesthetized for bursoscopy and phacoemulsification, respectively. Both were premedicated with intramuscular acepromazine (30 μg kg-1). The horses were sedated with intravenous (IV) medetomidine (7-9 μg kg-1 to effect), before anaesthetic induction with ketamine-diazepam. Anaesthesia was maintained with isoflurane in a mixture of oxygen and medical air, alongside a medetomidine constant rate infusion at 3.5 μg kg-1 hour-1. In recovery, 3 and 5 μg kg-1 of medetomidine were administered IV to cases 1 an...
Comparison of Ketamine/Diazepam and Tiletamine/Zolazepam Combinations for Anaesthesia Induction in Horses Undergoing Partial Intravenous Anaesthesia (PIVA): A Retrospective Clinical Study. The aim of this retrospective clinical study was to compare the combinations of ketamine/diazepam (KD group) and tiletamine/zolazepam (TZ group) for the induction of general anaesthesia in horses undergoing elective surgery. The data from the clinical and the anaesthetic records of 138 horses from 2021 to 2023 were evaluated, and the horses were divided in two groups: KD ( = 60) and TZ ( = 72). The horses were premedicated with romifidine and methadone IV; anaesthesia was induced with ketamine/diazepam for the KD group and tiletamine/zolazepam for the TZ group and was maintained with isofluran...
The effect of intramuscular atipamezole on head height and sedation scores in detomidine-sedated horses. To assess the effect of two different doses of intramuscular atipamezole on head height (HH) in horses after sedation with detomidine. Methods: Randomized, blinded, triple crossover study. Methods: Eight healthy adult horses. Methods: Baseline HH was measured before detomidine (40 μg kg) was injected intravenously. HH was measured at 10 and 20 minutes after injection. Then, saline, atipamezole 60 μg kg (AT60) or 120 μg kg (AT120) was injected intramuscularly. HH measurements were repeated at 10 minutes intervals for 100 minutes. HH data were analyzed with a linear mixed model. Significance ...
Anesthesia for non-obstetric surgery during late term pregnancy in mares. Submitting late-term pregnant mares to anesthesia for non-obstetric surgery raises concerns about the survival of the mother and fetus. This study aimed to evaluate and describe transient maternal and fetal hemodynamic changes during general inhalation anesthesia in mares during the last month of gestation. Nine adult mares in the last month of gestation were subjected to general inhalation anesthesia and dorsal recumbency for 90 minutes. Trans-anesthetic vital parameters, arterial hemogasometry, cardiac output, pulmonary arterial pressure, central venous pressure, and fetal heart rates were a...
Evaluation of the Rostral Inferior Alveolar Nerve Block via the Mental Foramen in Equids: In Vivo Efficacy Testing. The use of proper sedative and regional anesthetic protocols is essential when performing equine dental surgical procedures under standing sedation. The efficacy of the rostral inferior alveolar nerve block via the mental foramen has not been previously studied. Aims of this study included determining the efficacy of the block, investigating whether any region (labial mucosa, alveolar mucosa, or teeth) was more reliably anesthetized, and if differences in efficacy existed between bilateral and unilateral blocks. In this blinded trial, 10 horses each were randomly assigned to receive a left uni...