Evaluation of intranasal oxygen supplementation in mules anesthetized with the combination of ketamine, butorphanol, and guaifenesin

Abstract

Evaluation of intranasal oxygen supplementation in mules anesthetized ABSTRACTHypoxemia is a major complication of field anesthesia and no studies regarding this occurrence in mules has been done. Thus, the aim of this study was to evaluate intranasal oxygen supplementation (IOS) in mules (Equus caballus x Equus asinus) anesthetized with ketamine/butorphanol/guaifenesin combination. For this, we used six male, adult mules (322±29kg) which underwent premedication (MPA) with 0.2mg/kg of midazolam intramuscularly after 15 minutes, 0.02mg/kg detomidine IV 5 minutes after, induction IV with combination of ketamine (2mg/mL), butorphanol (22.5mg/mL), and guaifenesin (50mg/mL) (K/B/G) until lateral decumbency. Maintenance was done with the same anesthetic combination. The animals were submitted twice to the protocol described above, 20 days apart, forming two groups. CG: MPA, induction (0.92±0.24mL/kg (mean±SD)), and maintenance (2.2±0.2mL/kg/h) without SIO; TG: MPA, induction (0.98±0.17mL/kg), and maintenance (2.3±0.4mL/kg/h) with IOS flow 40mL/kg/h. During anesthesia arterial blood was collected every 20 minutes (T0, T20, T40, and T60) for blood gas analysis. Data analyzed by ANOVA followed by the Bonferroni test. P<0.05 was considered significant. Hypoxemia of the animals in the CG in periods (59±5; 55±5; 53±7; 49±8) with lower averages than the TG (160±4, 115±34, 92±25, 81±19) was observed, demonstrating that IOS increases PaO 2 avoiding the occurrence of hypoxemia.

Successful management of hypoxaemia in a mule during general anaesthesia

“…The present case report describes different treatment strategies and their effectiveness. Hypoxaemia is a known and common adverse effect in anesthetised horses 2,3 and has also been shown in other equids 16–18 …”

“…Hypoxaemia is a known and common adverse effect in anesthetised horses 2,3 and has also been shown in other equids. [16][17][18] The development of hypoxaemia in this mule was not expected because the mule was small and positioned in lateral recumbency. Both factors could be anticipated to help maintain arterial oxygenation.…”

“…15 The amount of research is sparse, but it has been shown that these species develop hypoxaemia under general anaesthesia similarly to the horse. [16][17][18][19] However, mules exist in a wide variety of weights and body shapes, which may lead to large variations in the development of hypoxaemia. 15 Perianaesthetic hypoxaemia is a common issue with equine patients, and treatment options are not always efficient.…”

“…Besides differences in drug requirements, no major relevant anatomical or physiological differences in pulmonary function are expected between horses, donkeys and mules 15 . The amount of research is sparse, but it has been shown that these species develop hypoxaemia under general anaesthesia similarly to the horse 16–19 . However, mules exist in a wide variety of weights and body shapes, which may lead to large variations in the development of hypoxaemia 15…”