The impact of vatinoxan on medetomidine-ketamine-midazolam immobilization in Patagonian maras (Dolichotis patagonum)

CARDIORESPIRATORY EFFECTS OF VATINOXAN IN BLESBOK (DAMALISCUS PYGARGUS PHILLIPSI) IMMOBILIZED WITH THIAFENTANIL-MEDETOMIDINE

Combinations of a low dose of opioid, such as thiafentanil, and a high dose of medetomidine, are increasingly being used for immobilization of African ungulates. Both drugs can have undesirable cardiorespiratory effects. In this study we assessed whether vatinoxan, a peripherally acting alpha2-adrenergic receptor antagonist, can be used to alleviate some of these effects without affecting the immobilization quality. Eight healthy, female, boma-confined blesbok (Damaliscus pygargus phillipsi), weighing a mean (SDtion) of 56.8 (4.4) kg, were immobilized twice in a randomized cross-over study with a 2-wk washout period using (1) 0.5 mg thiafentanil + 1.5 mg medetomidine (TM), (2) TM + vatinoxan: 0.5 mg thiafentanil + 1.5 mg medetomidine + 15 mg vatinoxan per milligram medetomidine (total of 22.5 mg, administered intramuscularly at 10 min post recumbency). Heart rate, respiratory rate, rectal temperature, oxygen saturation (SpO2), arterial blood pressure, and sedation scores from 1 to 5 (1 = limited effect; 5 = excessively deep) were measured every 5 min. Arterial blood gases (PaO2 and PaCO2) were measured at 10, 15, 25, and 35 min postrecumbency and the alveolar--arterial oxygen gradient (P[A-a]O2) was calculated. Induction times and immobilization quality did not differ between groups. The heart rate was significantly higher and the mean arterial pressure significantly lower in blesbok after receiving vatinoxan. All animals were hypoxemic and there were no significant differences in the respiratory rates, PaO2, PaCO2, SpO2, or P(A-a)O2 gradients at any time point. Although vatinoxan did not improve respiratory variables and blood oxygenation in these animals, the change in cardiovascular variables may suggest that it improves tissue perfusion, a positive outcome that requires further investigation.

EFFICACY OF TOLAZOLINE AND VATINOXAN IN REDUCING ADVERSE EFFECTS OF BUTORPHANOL-AZAPERONE-MEDETOMIDINE IMMOBILIZATION IN ROCKY MOUNTAIN ELK (CERVUS CANADENSIS)

A mixture of butorphanol, azaperone, and medetomidine (BAM) is frequently used for immobilization of North American hoofstock. Common adverse effects include respiratory depression, hypoxemia, and bradycardia. In this nonblinded crossover study the efficacy of two a-2 adrenergic antagonists, tolazoline and vatinoxan, were evaluated in alleviating adverse effects of BAM in Rocky Mountain elk (Cervus canadensis). Early administration of these antagonists was hypothesized to cause an increase in heart rate, respiratory rate, partial pressure of oxygen (PaO2) and hemoglobin oxygen saturation (SpO2), as well as reduction in mean arterial blood pressure without affecting sedation levels. Eight captive adult female elk were immobilized on three separate occasions at least 14 d apart with 0.15 mg/kg butorphanol, 0.05 mg/kg azaperone, and 0.06 mg/kg medetomidine. Tolazoline (2 mg/kg IM), vatinoxan (3 mg/mg medetomidine IV) or sterile saline (2 ml IM) were administered 20 min postinduction. The BAM caused hypoxemia, bradycardia, and moderate hypertension, and because of the severe hypoxemia observed, all animals received intratracheal oxygen throughout immobilization. Heart rate, respiratory rate, rectal temperature, SpO2, PaO2, and systolic, diastolic, and mean arterial blood pressure were monitored every 5 min throughout the immobilization. Intramuscular tolazoline caused a brief but significant drop in mean arterial pressure compared with controls and a brief but nonsignificant increase in heart rate. Vatinoxan caused a significant drop in blood pressure and a brief significant increase in heart rate. Changes in respiratory rates and PaO2 were not observed with either antagonist; however, all animals received oxygen, which may have influenced this result. The depth of sedation was unchanged after administration of either drug.

Clinical-haemostasis assessment of anaesthesia regimens in dogs with visceral and somatic types of pain response

The article investigates the influence of visceral (surgical treatment of abdominal pathologies) and somatic pain syndrome (osteosynthesis) on dogs’ clinical parameters and haemostasis. It was found, that the best variant for abdominal operations in dogs is acepromazine-ketamine-propofol anaesthesia and for osteosynthesis – acepromazine-butorphanol-ketamine. The use of neuroleptics (acepromazine, xylazine) with general anaesthetics (ketamine, propofol, sodium thiopental) in abdominal operations ensured rapid entry into anaesthesia (< 2 min) and duration 19–23 min. The use of acepromazine-ketamine-propofol provided well-managed anaesthesia during 11.1 ± 0.5 min, rapid recovery (17.3 ± 2.4 min), without significant changes in heart rate (HR), respiratory rate (RR), blood pressure (BP), haemoglobin saturation (SpO2). Unbalanced anaesthesia and insufficient analgesia under xylazine-ketamine caused a sharp decrease in HR, BP, RR with their increase due to visceral pain, led to hypoxia (SpO2 < 92%). During the osteosynthesis, acepromazine-butorphanol-propofol-ketamine anaesthesia provided complete analgesia with twice the rapid recovery of dogs without significant changes in HR, RR, BP, SpO2 during surgery. Acepromazine-ketamine-thiopental anaesthesia accompanied by pronounced analgesia with a decrease in HR and BP. Xylazine-ketamine-thiopental anaesthesia, under apparent analgesia, led to hypotension (decreased HR, BP) and hypoxia (decreased RR, SpO2). The data obtained will optimize the selection of drugs' combinations for dogs' anaesthesia, taking into account the type of pain response.