PHYSIOLOGIC EFFECTS OF THREE DIFFERENT PROTOCOLS OF ISOFLURANE ANESTHESIA IN CAPTIVE BROWN BROCKET DEER (MAZAMA GOUAZOUBIRA)

Abstract

This study evaluates the cardiorespiratory and physiologic effects of three different protocols of chemical restraint using isoflurane in captive brown brocket deer (Mazama gouazoubira). Six adult deer, two males and four females, aged 3-6 yr old and weighing 16.3 +/- 1.5 kg (mean +/- SD), were used. The deer were physically restrained and anesthetized using one of three protocols: protocol 1 (P1), anesthesia was induced directly with isoflurane using a facemask and maintained for 1 hr with isoflurane delivered by endotracheal tube; protocol 2 (P2), oral premedication with midazolam was followed 1 hr later by induction and maintenance of anesthesia with isoflurane, as in P1; and protocol 3 (P3), intravenous anesthesia using a combination of ketamine, xylazine, and atropine was followed by isoflurane anesthesia, as in P1. Cardiorespiratory variables were recorded during physical restraint (TO); 5 min after intubation (T5); and every 10 min during anesthesia (T15-T55). Venous and arterial blood gas analysis was conducted at TO (venous blood only), T15, T35, and T55. Data were analyzed by the appropriate statistical tests. P values < 0.05 were considered significant. Under P1, three deer regurgitated during induction and one of them died because of aspiration pneumonia. The end-tidal isoflurane concentration differed significantly between P1, P2, and P3 (2.6 +/- 0.2, 2.3 +/- 0.5, and 0.9 +/- 0.3%, respectively). Hypotension was observed during anesthesia (T15-T55). Respiratory acidosis occurred at all times and protocols, and pH was significantly lower in P1 compared to P2 and P3. Metabolic acidosis was also observed following physical restraint (T0-T35) in all protocols. The use of isoflurane via facemask for anesthesia induction is not a safe method in deer that are not premedicated. Isoflurane used alone or in combination with midazolam and ketamine-xylazine-atropine combination causes hypotension and dose-dependent respiratory acidosis.

Application of Nonhuman Primate Models in the Studies of Pediatric Anesthesia Neurotoxicity

“…Circulatory and respiratory inhibitions are common predictable adverse effects of general anesthesia using either inhalational or intravenous anesthetic agents. [61][62][63] Small animal models exposed to anesthetic agents need to have vital signs monitored and their normal physiological status maintained. 64 In animal models for anesthesia-induced developmental neurotoxicity, a range of measures have been designated to intensively monitor physiological parameters, including vital signs, blood oxygenation levels, and homeostasis, to assess if any alterations, including hypoxia or hypotension, occur during anesthetic exposure.…”

Anaesthetic management in adult reindeer (Rangifer tarandus tarandus) undergoing exploratory laparotomy for jejuno‐jejunal intussusception surgery resection

“…In addition, ambient temperature at the moment of general anaesthesia and surgical intervention was characteristic of winter conditions, which has been associated with lower dose requirements compared to higher ambient temperature conditions. 7,8 Moreover, butorphanol was chosen among other opioid drugs due to its short duration of action and mild sedative and analgesic effects, 13,14,[19][20][21][22][23][24][25][26][27][28][29][31][32][33] which allowed the animal to become recumbent and to prepare the surgical area without deep sedation nor cardiovascular depression. Several publications have shown that deer can be prone to hypoxaemia, especially when sedated with α2-adrenoreceptor agonists 5,22,34,35 ; for that reason, pre-oxygenation was maintained during the duration of the pre-operative period.…”

“…[15][16][17][18] Nevertheless, while these drug combinations have been reported more often during field anaesthesia, procedures that require longer anaesthesia duration demand a constant control of anaesthetic plane, which can be accomplished with inhalant anaesthetic agents. [19][20][21][22] To the authors' knowledge, the selection of the anaesthetic protocol of wild ungulates undergoing invasive procedures, such as an abdominal surgery, is poorly described in the literature. For this reason, here we report the anaesthetic management in a reindeer with jejuno-jejunal intussusception undergoing exploratory laparotomy and jejuno-jejuno anastomosis.…”

“…The addition of hyaluronidase to different anaesthetic protocols has also been described in wildlife species to facilitate capture 15–18 . Nevertheless, while these drug combinations have been reported more often during field anaesthesia, procedures that require longer anaesthesia duration demand a constant control of anaesthetic plane, which can be accomplished with inhalant anaesthetic agents 19–22 …”

Endotracheal tube obstruction with a blood clot following aspiration of rumen contents in a reindeer

“…Regurgitation is common in anaesthetised ruminants. Although not published in reindeer, it has been described in Tibetan yak, Shiras moose and brown brocket deer 4–6. Active regurgitation due to oesophageal contraction occurs under light planes of anaesthesia, while progressive abolishment of oesophageal muscle tone permits passive regurgitation under deep planes 7 8.…”