Reversal of arterial oxygen desaturation with the use of an oxygen concentrator during injectable anaesthesia in feral cats positioned in the Trendelenburg, dorsal or lateral surgical position

INTRODUCTION

This study observed the effects of oxygen supplementation, via an oxygen concentrator, on peripheral arterial blood oxygenation (SpO2) measured by pulse oximetry in anaesthetised cats undergoing spay in three different surgical positions. A total of 192 female feral cats were investigated for a large-scale trap-neuter-release program. Cats were anaesthetised with an intramuscular combination of butorphanol (0,4 mg / kg), ketamine (7-10 mg / kg) and medetomidine (0,03-0,05 mg / kg). Cats were randomly allocated to undergo spay in either Trendelenburg (TR) (70° downward head tilt), lateral (LR) or dorsal (DR) recumbency. Cats were breathing spontaneously either room air or 2 L/minute oxygen via a tight-fitting face mask. Pulse rate (in beats per minute), respiratory rate (in breaths per minute) and SpO2 (in percentage) were measured at baseline in left lateral recumbency and afterwards continuously after being positioned in allocated surgical position. At the end of surgery, cats were placed again in left recumbency, and all parameters were re-evaluated after five minutes. Overall, 33 % of cats showed severe arterial oxygen desaturation (SpO2 < 90 %) at baseline when breathing room air. When oxygen was supplemented during the procedure, arterial oxygen desaturation resolved in all cats. At the end of the procedure, 29 % of cats were hypoxaemic when oxygen was not supplemented, with an overall higher percentage of hypoxaemic cats in TR as compared to DR and LR recumbencies. All cats recovered well from surgery and were released within 24 hours post-anaesthesia. Arterial oxygen desaturation is frequent in cats anaesthetised with injectable anaesthesia for spay under field conditions. Oxygen supplementation administered via a tight-fitting mask resolved arterial oxygen desaturation in this feral cat population regardless of the surgical position and therefore oxygen supplementation is recommended in any case.

Analgesic Efficacy of Non-Steroidal Anti-Inflammatory Drug Therapy in Horses with Abdominal Pain: A Systematic Review

This systematic review aimed to identify the evidence concerning the analgesic efficacy of non-steroidal anti-inflammatory drugs to treat abdominal pain in horses, and to establish whether one non-steroidal anti-inflammatory drug could provide better analgesia compared to others. This systematic review was conducted following the "Systematic Review Protocol for Animal Intervention Studies". Research published between 1985 and the end of May 2023 was searched, using three databases, namely, PubMed, Embase, and Scopus, using the words equine OR horse AND colic OR abdominal pain AND non-steroidal anti-inflammatory drug AND meloxicam OR flunixin meglumine OR phenylbutazone OR firocoxib OR ketoprofen. Risk of bias was assessed with the SYRCLE risk of bias tool, and level of evidence scored according to the Oxford Centre for Evidence-based Medicine. A total of 10 studies met the inclusion criteria. From those only one study judged pain with a validated pain score, and a high risk of bias was identified due to the presence of selection, performance, and "other" types of bias. Therefore, caution is required in the interpretation of results from individual studies. To date, the evidence on analgesic efficacy to determine whether one drug is more potent than another regarding the treatment of abdominal pain in horses is sparse.

Cross-Reactivity and Functionality of Approved Human Immune Checkpoint Blockers in Dogs

BACKGROUND

Rodent cancer models have limitations in predicting efficacy, tolerability and accompanying biomarkers of ICIs in humans. Companion dogs suffering from neoplastic diseases have gained attention as a highly relevant translational disease model. Despite successful reports of PD-1/PD-L1 blockade in dogs, no compounds are available for veterinary medicine.

METHODS

Here, we assessed suitability of seven FDA-approved human ICIs to target CTLA-4 or PD-1/PD-L1 in dogs. Cross-reactivity and blocking potential was assessed using ELISA and flow cytometry. Functional responses were assessed on peripheral blood mononuclear cells (PBMCs) derived from healthy donors (n = 12) and cancer patient dogs (n = 27) as cytokine production after stimulation. Immune composition and target expression of healthy donors and cancer patients was assessed via flow cytometry.

RESULTS

Four candidates showed cross-reactivity and two blocked the interaction of canine PD-1 and PD-L1. Of those, only atezolizumab significantly increased cytokine production of healthy and patient derived PBMCs in vitro. Especially lymphoma patient PBMCs responded with increased cytokine production. In other types of cancer, response to atezolizumab appeared to correlate with a lower frequency of CD8 T cells.

CONCLUSIONS

Cross-functionality of atezolizumab encourages reverse translational efforts using (combination) immunotherapies in companion dog tumor patients to benefit both veterinary and human medicine.

Cats undergoing spay with medetomidine, ketamine and butorphanol develop arterial oxygen desaturation independent of surgical positioning and increased intraocular pressure in Trendelenburg position

INTRODUCTION

This study observed the effects of three different surgical positions on arterial blood oxygenation measured noninvasively by pulse oximetry (SpO2) and on intraocular pressure (IOP) in anaesthetised cats undergoing spay. A total of 222 female feral cats were anaesthetised for a large-scale trap-neuter-return program with an intramuscular combination of medetomidine (0.03 - 0.05 mg/kg), ketamine (7 - 10 mg/kg) and butorphanol (0.4 mg/kg). Cats were randomly allocated to undergo spay in either Trendelenburg (70° downward head tilt), lateral or dorsal recumbency. SpO2 and pulse rate were measured at baseline, prior to surgical positioning, after one minute in surgical position and in one-minute intervals after surgical incision. Intraocular pressure was measured before positioning and at the end of surgery. At the end of surgery, all cats were placed into left lateral recumbency and all parameters were revaluated after five minutes. No significant differences between the three positions were found regarding SpO2, but an increase over time was observed. In total, 52 ± 10% (mean ± SD) of cats were hypoxaemic (SpO2 < 90%) at baseline. SpO2 improved over time, but 27 ± 3% (mean ± SD) of the cats remained hypoxaemic at the end of surgery. Trendelenburg position increased IOP during surgery (mean 31 ± 6 mmHg, individual max. 48 mmHg, versus 17 ± 4 mmHg in dorsal/lateral recumbency) but normalised after 5 mins in lateral recumbence. All cats recovered well from surgery and were released within 24 hours post-anaesthesia. Surgical position was shown to have no notable influence on SpO2 during anaesthesia in cats not receiving oxygen supplementation, whereas Trendelenburg position led to increased IOP. Oxygen supplementation is recommended with this anaesthetic protocol, as hypoxaemia is frequently observed.

OMIP-065: Dog Immunophenotyping and T-Cell Activity Evaluation with a 14-Color Panel

Companion dogs are increasingly recognized as large-animal models of diseases such as cancer, infectious-, inflammatory-, or autoimmune diseases. At the same time, compared to human clinics, veterinarians have only a fraction of the treatment options available. To study the immunological aspects of canine diseases and ultimately develop or adapt human treatments for the dog, the methodology also needs to be in place. Such tools include robust and reliable flow cytometric panels. The purpose of the panel described here is to assess the immune cell composition and their functionality in the peripheral blood mononuclear cells (PBMCs) of dogs. Moreover, its "plug and play" composition allows for an in-depth analysis of T-cell responses in ex vivo assays (Table 1). Initially, this panel has been designed for the analysis of cryopreserved PBMCs to allow batched analysis and to reduce interexperimental variation. Withers and colleagues published a comparable and-to our knowledge-currently the most extensive canine panel to date (1). While their study focused on the aging and activation status of T cells in dogs, our panel is designed to look at a broader range of cells with a higher number of markers. This allows a more in-depth analysis of functional extracellular and intracellular markers. In addition, all antibodies in our proposed panel are directly labeled. In combination with suitable lymphocyte isolation protocols, this panel could potentially also be adapted to analyze tissue biopsies from various different organs. © 2020 International Society for Advancement of Cytometry.

The Influence of Anaesthetic Drugs on the Laryngeal Motion in Dogs: A Systematic Review

Simple Summary

Laryngeal paralysis is secondary to a loss of normal function of the larynx. Older dogs are particularly affected, with normal breathing becoming difficult. A successful diagnosis typically relies on the visualisation of either, complete, or partially absent, laryngeal movements. The use of anaesthesia drugs to provide sedation and stress relief is most commonly necessary during the diagnosis of laryngeal paralysis. While, the excessive administration of anaesthesia drugs may result in absent movements, the ideal anaesthesia regime remains unknown, and the use of sedation is questionable, given the potential for absent laryngeal movements, even in healthy dogs. In this systematic review, we found a potential benefit from using sedation during the evaluation of laryngeal function when compared to injectable anaesthetics only. The respiratory stimulant doxapram was effective in differentiating normal dogs from dogs with laryngeal paralysis but has associated safety hazards.

Abstract

Anaesthetic drugs are commonly used during the evaluation of laryngeal function in dogs. The aim of this review was to systematically analyse the literature describing the effects of anaesthetic drugs and doxapram on laryngeal motion in dogs and to determine which drug regime provides the best conditions for laryngeal examination. PubMed, Google Scholar, and EMBASE databases were used for the literature search up to November 2019. Relevant search terms included laryngeal motion, anaesthetic drugs and dogs. Studies were scored based on their level of evidence (LoE), according to the Oxford Centre for Evidence-based Medicine, and the quality was assessed using the risk-of-bias tool and SIGN-checklist. In healthy dogs, premedication before laryngeal examination provided better examination conditions and maintained overall adequate laryngeal motion in 83% of the studies. No difference in laryngeal motion between induction drugs was found in 73% of the studies but the effects in dogs with laryngeal paralysis remain largely unknown. Doxapram increased laryngeal motion in healthy dogs without serious side effects, but intubation was necessary for some dogs with laryngeal paralysis. Methodological characteristics varied considerably between studies, including the technique and timing of evaluation, number of assessors, study design, drug dose, combinations, route and speed of administration.

Outcome of Ventral Fusion of Two or Three Cervical Vertebrae with a Locking Compression Plate for the Treatment of Cervical Stenotic Myelopathy in Eight Horses

Objectives It was recently shown that biomechanical stability achieved with a locking compression plate (LCP) for ventral cervical fusion in horses is similar to the commonly used Kerf cut cylinder. The advantages of the LCP system render it an interesting implant for this indication. The goal of this report was to describe surgical technique, complications and outcome of horses that underwent ventral fusion of two or three cervical vertebrae with an LCP.

Methods Medical records of eight horses were reviewed for patient data, history, preoperative grade of ataxia, diagnostic imaging, surgical technique and complications. Follow-up information was obtained including clinical re-examination and radiographs whenever possible.

Results Two (n = 5) or 3 (n = 3) cervical vertebrae were fused in a mixed population with a median age of 9 months, median weight of 330 kg and median grade of ataxia of 3/5. A narrow 4.5/5.0 LCP (n = 6), a broad 4.5/5.0 LCP (n = 1) and a human femur 4.5/5.0 LCP (n = 1) were applied. Two horses were re-operated due to implant loosening. Six patients developed a seroma. Long-term complications included ventral screw migration in four, spinal cord injury in one and plate breakage in two horses at 720 to 1116 days after surgery. Outcome was excellent in three, good in four, poor in one patient.

Clinical Significance The use of an LCP for ventral cervical vertebral fusion is associated with good clinical results. However, a careful surgical technique is required to further reduce the complication rate.