Plus-Hex CLINICAL
Background
Donkeys are increasingly being seen in veterinary practice , and there has been a rise in the number of anaesthetics performed [ 1 ] . Donkeys are not small horses [ 1 ] and their needs during an anaesthetic procedure differ greatly from those of horses [ 2 ] . The handling and dosing requirements of donkeys also differ from those of horses .
The intravenous ( IV ) catheterisation of the jugular vein can be a challenge in donkeys , due to the musculature of their neck and thickened skin . Higher drug doses are often needed , and intubation is performed blindly ( similar to the horse ), which can be complicated due to the donkey ' s elongated head and position of the larynx [ 3 ] .
Regardless of their status under the American Society of Anesthesiologists ' ( ASA ) physical status classification system , donkeys are prone to a variety of complications during anaesthesia , including hypoventilation , hypotension and decreased ratio of arterial partial pressure of oxygen ( PaO 2
) to fraction of inspired oxygen
( FiO 2 ), leading to potential hypoxia / hypoxaemia .
Introduction
This case study provides an insight into a routine anaesthetic procedure on a donkey that was considered a normal healthy patient ( ASA Grade 1 ). Despite the routine nature of the procedure , complications occurred , including hypotension , hypercapnia and a reduced
PaO 2
: FiO 2 ratio , with the potential to progress to hypoxia . The study discusses these complications and how they were resolved .
Blood gas analysis is a vital tool in assessing a patient ' s status , particularly in relation to complications such as hypoventilation / hypercapnia , along with a reduced
PaO 2
: FiO 2 ratio . This report expands on the arterial blood gas results in this case , to develop understanding and improve patient care .
Ethical approval was obtained from the Institutional Animal Care and Use Committee of Ross University School of Veterinary Medicine , St . Kitts ( RUSVM ). The donkey was anaesthetised as part of a student exercise to perform castration . Students were closely supervised by veterinary anaesthesiologists and trained veterinary technicians .
Learning outcomes
• Evaluate the management of anaesthesia in an ASA Grade 1 donkey .
• Recognise common complications
• Identify the advantage of blood gas analysis
• Discuss the management of hypoxia / hypoxaemia
Patient signalment
Species Breed Age Sex Weight
Donkey Nevisian 2 years Male 135 kg
Case presentation
A 2-year-old , intact male Nevisian donkey weighing 135 kg was brought to RUSVM for a routine castration , which was to be performed as part of a teaching exercise . The donkey was a wild animal from the island of Nevis so , at the time of the initial evaluation , it had no known history . The physical examination on the day of surgery did not show any significant abnormalities ( Table 1 ).
Table 1 . Patient examination parameters and results , and normal ranges for a donkey [ 4 ] .
Parameter Result Normal range Heart rate 36 bpm 38 – 48 bpm
Respiratory rate
Rectal temperature
Mucous membranes
Capillary refill time
Lung and heart sounds
Packed cell volume
20 breaths / min 12 – 28 breaths / min
36.7 ° C 36.2 – 37.7 ° C
Pink and moist –
1 – 2 s < 2 s
Unremarkable –
36.1 % 23.67 – 38.08 % [ 4 ]
Total protein 74 g / l 58.4 – 69.3 g / l [ 4 ]
bpm , beats per minute .
Anaesthetic considerations
Hypotension is a common complication during anaesthesia , often due to the reduction in cardiac output caused by reduced cardiac contractility , vasodilation and / or bradycardia . Monitoring arterial blood pressure during anaesthesia provides an indirect assessment of cardiac output and oxygen ( O 2
) delivery . An anaesthetised donkey ' s systolic arterial
Volume 40 ( 2 ) • April 2025
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