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.
Evaluation of Gastric pH and Gastrin Concentrations in Horses Subjected to General Inhalation Anesthesia in Dorsal Recumbency. The prevalence of gastric disorders in high-performance horses, especially gastric ulceration, ranges from 50 to 90%. These pathological conditions have negative impacts on athletic performance and health. This study was designed to evaluate changes in gastric pH during a 24 h period and to compare gastrin concentrations at different time points in horses undergoing general inhalation anesthesia and dorsal recumbency. Twenty-two mixed-breed mares weighing 400 ± 50 kg and aged 8 ± 2 years were used. Of these, eight were fasted for 8 h and submitted to 90 min of general inhalation anesthesia i...
Severe orbital hematoma with third eyelid swelling and prolapse following a blind maxillary nerve block in a horse. A 20-year-old quarter horse gelding was presented for routine dental examination. Periodontal disease and luxation of tooth 108 was diagnosed and oral extraction was planned. After an unsuccessful blind maxillary nerve block, it was elected to perform the procedure under total intravenous anesthesia. Following recovery, a focal superficial corneal ulcer, severe retrobulbar swelling, mild exophthalmos, and marked swelling and prolapse of the third eyelid (nictitating membrane) were observed. Clinical signs persisted beyond 48 h despite the use of systemic anti-inflammatories and topical ocular ...
A newly developed recovery-enhancing device improves recovery scores during emergence from general anesthesia in horses: a randomized trial. To compare the quality of recovery in horses emerging from general anesthesia with or without the assistance of a novel device (recovery-enhancing device [RED]) designed to minimize high-energy falls. Methods: 20 mixed-breed horses, between July 1, 2023, and January 24, 2024. Methods: A computer-controlled belay system designed to slow the acceleration of a horse during a fall was evaluated in this study. Horses were randomly assigned to 1 of 2 treatment groups: RED (belay, assisted) or FREE (unassisted). An inertia-measuring unit was fitted to all horses and data were live streamed and record...
A transmandibular lateral transsphenoidal navigated surgical approach to access a pituitary macroadenoma in a warmblood mare. A 16-year-old warmblood mare was referred with a progressive history of behavioral changes and left-sided blindness. Following neuroanatomical localization to the forebrain, magnetic resonance imaging of the head revealed a well-delineated, 4.5 cm in diameter, round pituitary mass causing marked compression of the midbrain and optic chiasm. Euthanasia was recommended but declined by the owners. Veterinary specialists and a human neurosurgeon collaboratively prepared for surgical case management. A novel navigated transmandibular lateral transsphenoidal approach was developed to access the re...
Treatment of lidocaine-refractory ventricular tachycardia using procainamide in an anesthetized horse. To highlight the use of procainamide as a potential alternative treatment modality in cases of ventricular tachycardia that are refractory to lidocaine and magnesium sulfate. Methods: 1 adult horse weighing 380 kg. Unassigned: A 25-year-old Arabian gelding presented with severe colic signs. Due to persistent pain, it was elected to carry out an exploratory laparotomy. During the procedure a diagnosis of severe, unstable ventricular tachycardia was made based on the ECG findings, with an initial heart rate of 195 beats per minute and severe hypotension. Results: Initial treatment consisted of d...
Investigation of integrated time nanosecond pulse irreversible electroporation against spontaneous equine melanoma. Integrated time nanosecond pulse irreversible electroporation (INSPIRE) is a novel tumor ablation modality that employs high voltage, alternating polarity waveforms to induce cell death in a well-defined volume while sparing the underlying tissue. This study aimed to demonstrate the in vivo efficacy of INSPIRE against spontaneous melanoma in standing, awake horses. Unassigned: A custom applicator and a pulse generation system were utilized in a pilot study to treat horses presenting with spontaneous melanoma. INSPIRE treatments were administered to 32 tumors across 6 horses and an additional 1...
One-stage surgical case management of a two-year-old Arabian horse affected by male-pseudo hermaphroditism. A two-year-old Arabian horse presented for abnormal external genitalia and dangerous stallion-like behavior was diagnosed with disorder of sexual development (DSD), also known as intersex/hermaphroditism. Standing 1-stage surgical procedure performed under sedation, and local anesthesia to concurrently eliminate stallion-like behavior, risk of neoplastic transformation of intraabdominal gonads, and to replace ambiguous external genital with a functional, and cosmetically more acceptable anatomy. Step-1) Laparoscopic abdominal exploration and gonadectomy; Step-2) Rudimentary penis resection and...
Standing hand-assisted laparoscopic ovariohysterectomy to treat chronic pyometra in a mare. To describe a standing hand-assisted laparoscopic ovariohysterectomy in a mare. Methods: A 15-year-old maiden Oldenburg mare. Unassigned: The mare was presented for evaluation of bucking under saddle and uncharacteristic aggressive behavior. Evaluation of a 24-hour video of the mare in a stall showed behavior consistent with caudal visceral abdominal discomfort. Reproductive evaluation revealed a pyometra secondary to complete transluminal cervical adhesions. The mare was initially managed medically with disruption of the adhesions and uterine lavage, but the adhesions reformed within 6 weeks ...
Dural and deep cervical musculature anesthetic blockade for atlantoaxial collection of cerebrospinal fluid in horses. The analysis of cerebrospinal fluid has diagnostic, prognostic, and therapeutic value in neurological illnesses in horses. There are different methods for obtaining cerebrospinal fluid, with the collection between the C1 and C2 vertebrae being a more recent methodology, which allows the procedure to be performed in standing patients, without the limitations of general anesthesia and with a low contamination of the sample with blood, presenting itself as a practical alternative. This study evaluated the efficacy and safety of a local dural blockade in healthy horses submitted to cerebrospinal f...
Lower airway ultrasonographic, endoscopic, and cytological changes in horses undergoing inhalation anesthesia with controlled ventilation for minor elective surgeries. Effects of general anesthesia with controlled ventilation on the respiratory system have had limited evaluation in horses. A prospective observational study was performed with eleven client-owned horses undergoing elective surgery. Physical examination, auscultation with a rebreathing bag, complete blood cell count, lung ultrasound imaging, tracheal endoscopy imaging and transendoscopic tracheal wash were conducted before and 24 hours after anesthesia. Lung ultrasound imaging was also repeated just after recovery. A significant increase in blood neutrophil count between pre- and post-anesthesi...
Transient Horner’s syndrome in horses following cervical plexus local anesthesia. To report the development of transient Horner's syndrome in horses following local anesthesia of the cervical plexus. Methods: A total of 37 horses. Methods: Observational retrospective short case series. Methods: Medical records of cases undergoing ultrasound-guided cervical plexus anesthesia for standing prosthetic laryngoplasty at a single referral institution were evaluated (2019-2020). Results: Five of 37 horses (14%) developed transient signs of Horner's syndrome postoperatively. Obvious clinical signs began 2 to 5 h following local anesthesia and persisted for two to 4 h. Profuse un...
Effect of isolation protocols and cryoprotectants on freezing of stallion epididymal spermatozoa. The recovery of spermatozoa from the cauda epididymis may be the only option to obtain genetic material from elite stallions that had undergone castration or sudden death due to colic or severe injury. Objective: To evaluate two different protocols for retrieval of stallion epididymal spermatozoa and to evaluate different cryoprotectants on the freezability of the epididymal spermatozoa. Methods: Six epididymides from three stallions were collected immediately after routine castration under general anesthesia. In the first experiment, each epididymis (of two testes) of the same stallion were p...
Standing gustatory papillae biopsy procedure for antemortem diagnosis of equine grass sickness. Diagnosing equine grass sickness (EGS) requires histopathological evidence of chromatolysis and/or neuronal loss in peripheral autonomic ganglia. Previous investigators performed postmortem biopsies of gustatory papillae located on the tongue and found chromatolytic subgemmal neurons in all 13 EGS horses. The present study aimed to design a standardized lingual biopsy sampling method through a transbuccal approach in healthy standing horses and assess the quality of the obtained samples, to allow antemortem diagnosis of EGS in clinical cases. Methods: 6 healthy horses. Methods: A transbuccal a...
Large animal ventilator-integrated volumetric capnography generates clinically acceptable values of physiologic dead space in anesthetized healthy adult horses. To evaluate the agreement between the Tafonius large animal ventilator-integrated volumetric capnography (vCap) software and the Respironics NICO noninvasive cardiac output monitor reference system. Methods: Data were collected from 56 healthy adult horses undergoing general anesthesia. Methods: Animals were placed under general anesthesia and connected to the Tafonius large animal ventilator circle system. A flow partitioning device with CO2 and flow sensors was utilized to couple the endotracheal tube to the NICO monitor. Tafonius CO2 and flow sensors are incorporated into the Y-piece of the...
Dose effect and duration of action of liposomal bupivacaine administered as a perineural analgesic in a reversible and adjustable frog-pressure model of equine lameness. To determine the dose effect of peri-neural liposomal bupivacaine (LB) in an induced forelimb lameness model. Methods: 12 clinically normal adult horses. Methods: A randomized cross-over design was performed with 1 limb receiving saline and the other LB: low dose (6), high dose (6). Lameness was induced in 1 forelimb using a frog-pressure model. In the lame limb, peri-neural injection of the palmar nerves at the proximal sesamoid bones was performed using saline, low dose LB (0.25 mg/kg) (LDLB), or high dose LB (0.5mg/kg) (HDLB) in random order with a 1-week washout period between treatments. ...
Sperm Quality Assessment in Stallions: How to Choose Relevant Assays to Answer Clinical Questions. Stallion sperm analysis is indicated for infertility diagnosis, pre-sale expertise, production of fresh or frozen doses, and frozen straw quality control. Various collection methods are described, and numerous assays can be performed on semen. Determining an approach for each of these cases is challenging. This review aims to discuss how to obtain relevant clinical results, answering stallion owners' concerns. Semen can be collected with an artificial vagina on a phantom or a mare, by electro-ejaculation under anesthesia, or after pharmacological induction. The collection method influences the...
Long-term outcome after colic surgery: retrospective study of 106 horses in the USA (2014-2021). To determine long-term survival rate, defined as survival to 1 year after discharge from the hospital, and rate of return to prior athletic, breeding, or other function in horses undergoing colic surgery at the first presentation at one referral hospital in the Pacific northwest region of the United States. Unassigned: Records were reviewed for all horses that underwent colic surgery between October 2014 and October 2021. Owners of horses that survived to discharge were contacted to obtain follow-up information via internet-based questionnaire or telephone interview. The percentage of horses...
Successful total hip arthroplasty in a miniature horse. To describe the surgical treatment, postoperative management, and outcome of a miniature horse undergoing total hip arthroplasty (THA). Methods: Case report. Methods: A 4-year-old miniature horse stallion weighing 85 kg. Methods: The horse presented with left coxofemoral luxation of ~6 weeks duration. Computed tomography confirmed craniodorsal luxation with marked degenerative changes to the femoral head. The horse underwent THA using cementless press fit implants, including an interlocking lateral bolt for the femoral stem. Results: The horse recovered well from anesthesia but suffered a ...
A comparison of rectal versus fetlock temperatures in dorsally recumbent horses during general anesthesia. To investigate the effect of isoflurane anesthesia on thermoregulation and peripheral heat loss in dorsally recumbent horses. Methods: Prospective, clinical study. Methods: Seven adult horses (2.6 ± 1.5 years old, 455 ± 70.2 kg). Methods: Horses underwent elective surgical procedures in dorsal recumbency under general anesthesia (GA) maintained with isoflurane in oxygen. Rectal (TR), intranasal (TN) and fetlock surface temperatures (TF) were measured every 10 minutes for the first 80 minutes following induction of GA. Room temperature (TRO) was monitored during the study. Statistical analysi...
Xylazine Infusion during Equine Colic Anesthesia with Isoflurane and Lidocaine: A Retrospective Study. This retrospective study investigated the effect of a xylazine infusion on heart rate; mean arterial pressure; blood gases; anesthetic and dobutamine requirements; recovery quality and duration; percentage of death/survival; and days to die/discharge in horses after colic surgery under partial intravenous anesthesia with isoflurane and lidocaine infusion. Anesthetic records of equine colic surgery were reviewed from similar periods in 2020-2021 and 2021-2022. In both groups, after sedation with xylazine 0.7 mg/kg intravenously (IV) and induction with ketamine 2.2 mg/kg and midazolam 0.06 mg/kg...
Endoscope-assisted three-wire technique for extensive nasal septum resection in horses. To describe a 3-wire method with endoscopic guidance for extensive nasal septum resection. Methods: Retrospective study. Methods: Thirteen horses with nasal septum diseases. Methods: In anesthetized horses in left lateral recumbency, endoscopic guidance was used to place obstetrical wires for the ventral and caudal incisions in the nasal septum and a trephine opening was used to place the dorsal wire. The rostral aspect of the septum was incised with a scalpel, followed by incisions with the preplaced wires, and the nasal passages were packed with gauze. Horses were recovered with a temporary ...
Treatment of a Paroxysmal Atrioventricular Block by Implantation of a Bipolar, Single-Chamber Cardiac Pacemaker in a Donkey. A two-year-old donkey presented with recurrent syncope. Electrocardiography revealed periods without any atrioventricular conduction and without any ventricular escape rhythm with a duration of up to one minute. Finally, atrioventricular conduction resumed spontaneously with a preceding ventricular escape beat. Laboratory tests and echocardiography identified no reversible cause. The diagnosis of a paroxysmal atrioventricular block (PAVB) was made. Therefore, a single-chamber cardiac pacemaker was implanted under general anesthesia. The device was programmed in the VVI mode to prevent further ...
Topical ropivacaine hydrochloride 0.5% and lidocaine hydrochloride 2% significantly reduce corneal sensitivity without short-term negative side effects in horses. To evaluate corneal sensitivity and acute side effects following application of ropivacaine hydrochloride 0.5% and lidocaine hydrochloride 2% on the healthy equine cornea. Ropivacaine and lidocaine similarly decreased corneal sensitivity when applied topically without clinically evident short-term ocular side effects. Lidocaine may be preferable in clinical settings due to its large, multi-use vials and similar effects to ropivacaine.
Antimicrobial prophylaxis is not indicated for horses undergoing general anaesthesia for elective orthopaedic MRI. Post-anaesthetic fever is a known complication of general anaesthesia, however, its incidence in horses undergoing elective magnetic resonance imaging (MRI) is unknown. Objective: To determine the incidence of post-anaesthetic fever in horses undergoing elective orthopaedic MRI and determine whether prophylactic antimicrobial therapy would be associated with a reduction in the incidence of post-anaesthetic fever. We hypothesised that prophylactic antimicrobials would be associated with a reduction in the incidence of post-anaesthetic fever. Methods: Retrospective cross-sectional study. Methods...
Evaluation of frontal and infratrochlear nerve blocks for standing sedated frontonasal sinusotomy in horses. To determine if targeted blocking of frontal and infratrochlear nerves provided anesthesia for the approach to a frontonasal sinusotomy. Methods: Two part study: Part 1 randomized crossover design; Part 2 proof of concept. Methods: N = 12; six each in Parts 1 and 2. Methods: Part 1: Each horse had either frontal and infratrochlear nerve blocks or a line block performed with 2% mepivacaine hydrochloride. Mechanical nociceptive thresholds (MNT) were obtained at five sites along a proposed frontonasal sinusotomy prior to injection, and at 10, 60, and 120 min after blocking. After a 4 day ...
Laparoscopic cryptorchidectomy using a resorbable self-locking loop device in dorsally recumbent horses. To report the use and feasibility of a self-locking resorbable loop device for cryptorchidectomy. Methods: Clinical prospective study. Methods: Twenty horses. Methods: Horses suspected to have an abdominal testicle/s after admission work-up were enrolled. Horses were anesthetized in dorsal recumbency and a standard laparoscopic technique was performed. The looped device was inserted into the abdomen, glided around the testis/cord and tightened. Then, the spermatic cord was transected prior testis removal. Surgical procedure details and remarks, perioperative complications and total surgical ti...
Post-anesthetic CPS and EQUUS-FAP scores in surgical and non-surgical equine patients: an observational study. Equine pain scoring may be affected by the residual effect of anesthetic drugs. Unassigned: To compare pain scores in the hours immediately following anesthetic recovery to baseline pre-anesthetic scores in equine patients undergoing surgical and non-surgical procedures. Unassigned: Clinical observational study. Unassigned: Fifty adult horses undergoing anesthesia for surgical or non-surgical procedures were enrolled. Horses underwent pain scoring using the Composite Pain Score (CPS) and Equine Utrecht University Scale for Facial Assessment of Pain (EQUUS-FAP) prior to anesthesia (T0) and foll...
Pyelonephritic end-stage kidney and ureterocutaneous fistula in a Shetland pony. A 12-y-old Shetland Pony was presented with a mucus-secreting fistula in the right paralumbar fossa. Surgery was performed to unravel the origin of the fistula. The horse died under anesthesia and was forwarded to autopsy. The right kidney was markedly atrophic and fibrotic, consistent with unilateral end-stage kidney. The right ureter was markedly thickened, but with luminal continuity leading into the urinary bladder where a partial obstruction caused by nodular para-ureteral fat necrosis was evident. The lumen of the cutaneous fistula was continuous with the right ureter; therefore, we diag...
Restoration of function following traumatic superior eyelid avulsion in a horse treated with advancement flap blepharoplasty (H-plasty) and subdermal hyaluronic acid filler. To describe the successful restoration of superior eyelid function in a horse following traumatic avulsion using an advancement flap blepharoplasty and subdermal hyaluronic acid filler. Methods: A 21-year-old American Paint Horse stallion who was attacked by a fellow stallion resulting in numerous traumatic injuries including avulsion of approximately 75% of the left superior eyelid. Methods: With standing sedation and locoregional anesthesia, the superior eyelid wound was debrided and an advancement flap blepharoplasty (H-plasty) and temporary tarsorrhaphy were performed. Routine healing of t...
Effects of subconjunctival ropivacaine, liposomal bupivacaine, and mepivacaine on corneal sensitivity in healthy horses. To evaluate corneal sensitivity and adverse events following subconjunctival administration of three local anesthetics in horses. Methods: Randomized, masked, crossover study. Methods: Twelve healthy adult mares. Methods: The subconjunctival space of the treated eye was injected with 0.2 mL of liposomal bupivacaine (1.3%), ropivacaine (0.5%), or mepivacaine (2%). All horses received each medication once and the contralateral eye received saline (control). Corneal touch threshold (CTT) was measured using a Cochet-Bonnet esthesiometer before sedation, after sedation, and at specified intervals...