Anesthesia and Analgesia for Standing Equine Surgery

Sedation with dexmedetomidine-butorphanol or xylazine-butorphanol continuous intravenous infusions during unilateral ovariectomy in standing donkeys

BACKGROUND

Intravenous infusions of alpha-2 adrenoceptor sedatives and opioids can potentially facilitate surgery in donkeys while standing. Literature on this subject matter is scant.

OBJECTIVES

Evaluation of efficacy of sedation from α2 -adrenoceptors (dexmedetomidine or xylazine) and butorphanol during ovariectomy in standing donkeys.

STUDY DESIGN

Randomised, masked in vivo experiment.

METHODS

Thirteen female donkeys were sedated with butorphanol (0.05 mg/kg bwt followed by 0.05 mg/kg bwt/h) IV. Concomitantly, 6 of the 13 jennies were sedated with dexmedetomidine 2.5 mcg/kg bwt followed by 2.5 mcg/kg bwt/h (Dex-B group), while seven jennies were sedated with xylazine 0.5 mg/kg bwt followed by 0.5 mg/kg bwt/h (Xyl-B group). A line block of the left flank and an infiltration block around uterine ligament were performed with lidocaine. While the jennies underwent ovariectomies standing, sedation scores and head height above ground were assessed at 2 and 10 min after sedative boluses and every 10 min thereafter. If sedation was too light or too deep, the dose of dexmedetomidine or xylazine was increased or decreased by 25% of the original infusion rate, while butorphanol infusion rate was constant. Physiological parameters were measured. Normally distributed data were compared using the two-sample t test while repeatedly measured data were tested for differences between and within groups using repeated measures analysis of variance (ANOVA) by ranks followed by a Wilcoxon test with Tukey Honest Significant Difference for multiple testing. Statistical significance was set at p < 0.05.

RESULTS

Both Dex-B and Xyl-B caused moderate to marked sedation adequate for ovariectomy in donkeys. Evident sedation was absent by 60 min of termination of infusions. No adverse physiological effects were observed.

MAIN LIMITATIONS

Study on ovariectomy cases only, no pharmacokinetic profiling.

CONCLUSIONS

Dexmedetomidine or xylazine and butorphanol sedation is feasible for ovariectomy in standing donkeys.

Standing surgery among equine board certified surgeons: Survey regarding current use and trends

BACKGROUND

Publications about equine standing surgery are flourishing, however, information regarding its use and prevalence among surgeons is still limited.

OBJECTIVES

To determine the current use and recent trends for equine standing surgery among board certified surgeons and to identify the main reasons and limitations for performing a procedure standing.

STUDY DESIGN

Cross-sectional survey.

METHODS

A 139-item questionnaire was sent by email to 733 large animal surgery Diplomates (ACVS and ECVS) from November 2020 to February 2021. The survey collected demographic information and general data regarding standing surgery before being divided into seven identical sections for each body system, involving 36 standing procedures.

RESULTS

The survey response rate was 29.7% (218/733). Most respondents (58.9%, 126/214) had performed standing surgery for <10 years regardless of length of time they were board certified (48.2% board certified <10 years and 51.8% >10 years). Most respondents (range: 50.0%-92.9%, mean 69.5%) changed from performing 14/36 surgeries under general anaesthesia (GA) to standing within the previous 10 years and had always performed 8/36 surgeries standing (51.6%-73.9%, mean 61.4%) regardless of board certification time. Surgeons board certified <10 years ago performed more often 3/36 listed procedures standing than those board certified >10 years ago (p < 0.05). Avoiding GA (179/218) and/or reducing procedure cost (111/218) were the two main reasons to perform standing surgeries whereas the horse's behaviour (183/218) and/or the patient size/age (94/218) were the two main limiting factors.

MAIN LIMITATIONS

Low response rate. Results biased towards the opinion of a subgroup of surgeons, those performing standing surgery. Some standing procedures were not included in the survey.

CONCLUSIONS

The use of standing surgery is well established among board certified surgeons and progressively increasing, especially in the last 10 years and among recent Diplomates. With increased training and awareness, more Diplomates may be encouraged towards performing standing surgeries.

Basic Postoperative Care of the Equine Colic Patient

The 3 time periods around colic surgery (preoperative, operative, and postoperative) are all critical to successful outcomes. Although much focus is often paid to the first 2 time periods, the importance of sound clinical judgment and rational decision-making in the postoperative period cannot be overstated. This article will outline the basic principles of monitoring, fluid therapy, antimicrobial therapy, analgesia, nutrition, and other therapeutics routinely used in patients following colic surgery. Discussions of the economics of colic surgery and expectations for normal return to function will also be included.

Current Use of Equine Laparoscopy in Urogenital Disorders: A Scoping Review of the Literature from 2000 to 2021

(1) Background: Laparoscopic surgery replaced traditional invasive techniques for the treatment of common urogenital disorders in equids. The aim of this review is to evaluate applications and the development of urogenital laparoscopy from 2001 to 2021. (2) Methods: A scoping review of literature was undertaken according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines for scoping reviews on three databases (NCBI-PubMed, Web of Science-Thompson Reuters, and SciVerse Scopus). (3) Results: A total of 452 papers were identified. After duplicate removal and title screening, 181 papers underwent abstract screening. Of these, 160 + 10 papers (cited by others) were assessed for eligibility according to the PICOs. A total of 132 papers were considered eligible. Most of the research was focused on ovaries and testes, followed by urinary bladder and general articles about laparoscopy in horses. We identified 43 original studies (33%, RCT, NoRCT, and experimental trials), 39 case series/retrospective studies (29%), 37 case reports (28%), and 13 reviews (10%, narrative or systematic). (4) Conclusions: Gonadal disorders were the most investigated. Hand-Assisted Laparoscopic Surgery (HALS) and laparoscopic-assisted surgery represent valuable options for more challenging conditions (uterine and urinary bladder disorders).

Analgesic and Sedative Effects of Epidural Lidocaine-Xylazine in Elective Bilateral Laparoscopic Ovariectomy in Standing Mule Mares

Simple Summary

Elective bilateral ovariectomy in mule mares is recommended to correct undesirable behaviour effects related to oestrus and also in order to improve work performance. This procedure is usually carried out in a standing position with a combination of sedative and analgesic drugs along with local anaesthesia of the ovarian pedicles. The aim of the study was to evaluate the effects of epidural lidocaine-xylazine in sedated standing mules undergoing elective bilateral laparoscopic ovariectomy. The findings suggest that no significant changes were found in heart rate, respiratory rate, rectal temperature with respect to baseline values. Sedation and analgesia were satisfactory in six out of the eight mules. Epidural analgesia with lidocaine-xylazine may be a good alternative to local anaesthetics infiltration of the ovarian pedicle for elective bilateral laparoscopic ovariectomy in standing mule mares, but further studies should be performed.

Abstract

The purpose of this study was to determine the analgesic efficacy and safety of epidural lidocaine-xylazine administration in standing mules undergoing elective bilateral laparoscopic ovariectomy in order to suppress unwanted behaviour. Eight mule mares were sedated with intramuscular 0.05 mg/kg acepromazine followed by 1.3 mg/kg of xylazine and 0.02 mg/kg of butorphanol intravenously. Sedation was maintained by a constant rate infusion of 0.6 mg/kg/h of xylazine. The paralumbar fossae were infiltrated with 30 mL of 2% lidocaine. Epidural anaesthesia was performed at the first intercoccygeal space with 0.2 mg/kg of lidocaine and 0.17 mg/kg of xylazine. After 15 min, bilateral laparoscopic ovariectomy was performed. Heart rate, respiratory rate, rectal temperature, invasive arterial blood pressure, degree of analgesia, sedation and ataxia were evaluated during surgery. The laparoscopic ovariectomy was successfully completed in all animals. Sedation and analgesia were considered satisfactory in six out of the eight mules. In conclusion, caudal epidural block allowed surgery to be easily completed in six out of eight. The animals did not show any signs of discomfort associated with nociception and were mostly calm during the procedures, however additional studies are needed to establish epidural doses of xylazine and lidocaine that result in reliable abdominal pain control in mules for standing ovariectomy.

Post-operative pain behaviour associated with surgical castration in donkeys (Equus asinus)

Background

Recognising pain in donkeys is challenging because they are stoic.

Objectives

To identify the responses of donkeys before and after surgical pain.

Study design

Prospective, short‐term longitudinal pre‐ and post‐intervention observations.

Methods

Forty adult donkeys underwent surgical castration after sedation with intravenous (IV) xylazine, induction with guaiphenesin/thiopental IV and maintenance of anaesthesia with isoflurane and local anaesthetic blockade. Four hours after recovery from anaesthesia, flunixin meglumine 1.1 mg/kg, dipyrone 10 mg/kg and morphine 0.2 mg/kg IV were administered. Behavioural responses exhibited by the animals housed in individual stalls were recorded in four 30‐min videos: before castration (M0), and 3.5‐4.0 hours (M1), 5.5‐6.0 hours (M2) and 23.5‐24.0 hours after recovery from anaesthesia (M3). To exclude the influence of insects, the behaviour of six apparently pain‐free donkeys was compared with and without the presence of faeces and urine in the stall.

Results

When compared with presurgical baseline behaviours (M0), after surgery (M1) donkeys raised their pelvic limbs more (P = .003). When compared with M1, after analgesia (M2), the median frequencies of ear movements (44 vs 16; P < .001), head shaking (7 vs 1; P < .001), head turning (5 vs 0; P < .001) and lifting of the both limbs (7 vs 0; P = .008) decreased; feeding (0 vs 29; P < .001) and water intake (0 vs 0, range 0‐1 vs 0‐7; P = .05) increased. The dirty stall increased tail (53 vs 80; P = .03), head (16 vs 30; P = .03) and ear movements (50 vs 78; P = .04).

Main limitations

The dirty stall and presence of insects possibly contributed to the expression of behaviours unrelated to pain.

Conclusion

Lifting the pelvic limbs was the only specific pain behaviour after castration in donkeys. Analgesia restored appetite and water intake and reduced the frequency of head shaking and turning, ear movement and lifting the limbs. Tail, head and ear movements are unspecific responses related both to pain and a dirty stall, and are confounding factors when pain is assessed in donkeys in the presence of insects.

Behavioral and Cardiopulmonary Effects of a Constant Rate Infusion of Remifentanil-Xylazine for Sedation in Horses

Xylazine and remifentanil in constant rate infusion (CRI) could be used for sedation in horses without adverse effects. The objective was to evaluate behavioral and cardiopulmonary effects of an intravenous (IV) infusion of xylazine and remifentanil for sedation in horses. Xylazine (0.8 mg/kg IV) followed after 3 minutes by a CRI of xylazine and remifentanil (0.65 mg/kg/h and 6 μg/kg/h, respectively) was administered in 10 healthy horses for 60 minutes. Sedation, ataxia, and cardiopulmonary, hematological, and blood gases variables were evaluated. Heart rate decreased significantly during the first 25 minutes after CRI of xylazine and remifentanil, whereas the respiratory rate showed a significant decrease at 20 minutes and remained significantly low until the endpoint. There were no statistically significant fluctuations in blood arterial pressure, blood pH, partial pressure of arterial carbon dioxide, lactate, creatinine, calcium, chlorine, and sodium, compared with baseline values. Blood partial pressure of arterial oxygen and bicarbonate values were significantly higher compared with baseline values, whereas potassium decreased. Sedation and ataxia developed immediately after the administration of xylazine in all horses. All horses recovered successfully within 10 minutes after interruption of the CRI of xylazine and remifentanil, with no ataxia. No adverse effects were observed. The use of a combination of xylazine and remifentanil as sedation protocol has no adverse effects at the described dosage.

Ceratohyoidectomy in standing sedated horses

OBJECTIVE

To investigate the feasibility and complications associated with ceratohyoidectomy (CHE) in standing sedated horses unaffected (experimental horses) and standing sedated horses affected (clinical cases) with temporohyoid osteoarthropathy (THO).

STUDY DESIGN

Case series.

ANIMALS

Six experimental horses and four clinical cases.

METHODS

Standing CHE was performed in six experimental horses euthanized 30 minutes (n = 3) and 7 days (n = 3) postoperatively. The four clinical cases were presented because of central facial nerve paralysis (n = 3), vestibular ataxia (n = 3), auricular hemorrhage (n = 2), quidding (n = 1), and oesophageal impaction (n = 1). Evolution was assessed by clinical examination during hospitalization and later by telephone interviews for the clinical cases.

RESULTS

The procedure was successfully performed in all horses. Experimental horses did not show any short-term postoperative complications. Hemorrhage was experienced intraoperatively in one of the clinical cases and was successfully managed with placement of hemostatic forceps. Vestibular ataxia and other symptoms of THO improved within days, but facial nerve paralysis did not improve until 9 days to 6 months after surgery. Follow-up ranged from 9 to 24 months. All clinical cases returned to performance, and client satisfaction was excellent.

CONCLUSION

Ceratohyoidectomy was consistently feasible in standing sedated horses. The method did not result in postoperative complications and led to resolution of clinical signs associated with THO.

CLINICAL SIGNIFICANCE

Standing CHE should be considered in horses affected with THO, especially when horses present with marked vestibular deficits and ataxia, to reduce risks associated with recovery from general anesthesia.

Is There Still a Place for Lidocaine in the (Postoperative) Management of Colics?

Intravenous lidocaine is widely used to prevent or treat postoperative ileus in horses. Clinical studies that support this approach are flawed and contradicted by others. Also, physical obstruction could be more important in causing postoperative reflux than postoperative ileus in the horse. The antiinflammatory properties of lidocaine and the role of inflammation from intestinal handling in the genesis of postoperative reflux are questionable. Because of cost and questionable efficacy of lidocaine, a well-designed clinical trial is required to support its continued use. However, lidocaine could be given to provide or enhance analgesia in selected cases with postoperative colic.

Clinical applicability of detomidine and methadone constant rate infusions for surgery in standing horses

OBJECTIVE

To determine the required rate of a detomidine infusion (loading dose 5 μg kg^-1; initial rate 12.5 μg kg^-1 hour^-1) added to a constant infusion of methadone (0.2 mg kg^-1; 0.05 mg kg^-1 hour^-1) for sedation in standing horses and ponies undergoing elective surgeries with appropriate local anaesthetic techniques.

STUDY DESIGN

Prospective, clinical study.

ANIMALS

Adult, healthy, client-owned, non-food-producing horses or ponies sedated for elective standing surgeries longer than 45 minutes.

METHODS

At baseline (in the stables before administration of sedative agents), at 10 minutes after sedation and every 5 minutes thereafter, ataxia, sedation and surgical condition were evaluated; each scored 0-3. These scores were used to adjust the detomidine administration rate using the Ghent Sedation Algorithm. A 10 cm visual analogue scale (VAS) was used by the main surgeon at the end of the procedure to evaluate the surgical conditions. Heart rate, systolic arterial pressure and respiratory frequency were also recorded at each time point. For statistical analysis, anova for normal, Kruskal-Wallis H-test for non-normal variables, and Mann-Whitney U test for VAS were used.

RESULTS

From the 42 horses/ponies included in this study, 28 underwent dental procedures and 14 other types of procedures. Overall, dental procedures required higher mean detomidine rates compared with other types of surgeries (16.9 ± 4.5 versus 9.0 ± 1.9 μg kg^-1 hour^-1) (p < 0.001). Dental procedures were assigned similar VAS scores, median (range), of 7.8 (5.8-10) with other procedures, 8.7 (2.8-10). Cardiovascular changes were not clinically significant. No signs or behavioural changes of abdominal pain were observed postoperatively.

CONCLUSIONS AND CLINICAL RELEVANCE

Satisfactory surgical conditions were achieved using a combination of detomidine and methadone infusions with locoregional anaesthesia, with no adverse effects. Dental procedures required higher detomidine dose rates compared with other surgeries.

Applications of mesenchymal stem cell technology in bovine species

Mesenchymal stem cells (MSCs) have received a great deal of attention over the past 20 years mainly because of the results that showed regeneration potential and plasticity that were much stronger than expected in prior decades. Recent findings in this field have contributed to progress in the establishment of cell differentiation methods, which have made stem cell therapy more clinically attractive. In addition, MSCs are easy to isolate and have anti-inflammatory and angiogenic capabilities. The use of stem cell therapy is currently supported by scientific literature in the treatment of several animal health conditions. MSC may be administered for autologous or allogenic therapy following either a fresh isolation or a thawing of a previously frozen culture. Despite the fact that MSCs have been widely used for the treatment of companion and sport animals, little is known about their clinical and biotechnological potential in the economically relevant livestock industry. This review focuses on describing the key characteristics of potential applications of MSC therapy in livestock production and explores the themes such as the concept, culture, and characterization of mesenchymal stem cells; bovine mesenchymal stem cell isolation; applications and perspectives on commercial interests and farm relevance of MSC in bovine species; and applications in translational research.