| dc.description.abstract | Epidural anaesthesia is one of the method of administering drugs in close proximity to their site
of action either at the receptors in the dorsal horn of the spinal cord or at the nerves as they leave
the spinal cord. The technique is part of the emerging trends in pain management in small
animals, especially for surgical conditions caudal to the umbilicus. Different drug protocols have
been used to provide epidural anaesthesia in dogs. The objectives of this study were: to carry out
a survey of surgical procedures carried out caudal to the umbilicus in dogs, the anesthetic and
analgesic drugs and techniques employed for these procedures in small animal veterinary
practices in Nairobi County, Kenya; to evaluate the hematological, cardiopulmonary, rectal
temperature changes, and anaesthesia and analgesia produced following lumbosacral epidural
administration of lidocaine, xylazine, ketamine and their combinations in dogs.
A questionnaire was used to carry out the survey on anaesthesia practices in phase one of the
study. Phase two constituted the experimental study, where fifteen dogs were randomly divided
into three groups (A, B and C) of five dogs each. Every animal in each group received two
treatments one week apart. Each dog was premedicated with acepromazine (0.1mg/kg)
intramuscularly prior to injection of the experimental drugs. Dogs in group A were injected with
lidocaine epidurally (4 mg/kg) and after one week, the drug combination lidocaine-xylazine (2
mg/kg and 0.3 mg/kg, respectively). Dogs in group B were injected with xylazine epidurally (0.6
mg/kg) and one week later, with xylazine-ketamine (0.3 mg/kg and 1 mg/kg, respectively). Dogs
in group C were injected with ketamine epidurally (2 mg/kg) followed one week later with the
combination of lidocaine-ketamine (2 mg/kg and 1 mg/kg, respectively).
Blood samples were collected at 0, 15, 30, 60, 120, 180 and 240 minutes after drug injection and
the following blood parameters analyzed: hemoglobin concentration, packed cell volume, total
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leukocyte count, total erythrocyte count, and total platelet count. Heart rate, respiratory rate and
rectal temperature were assessed at 0, 5, 10, 15, 30, 45, 60, 75, 90, 120, 150, 180, 210 and 240
minutes after drug injection. Analgesia was evaluated in a 4-point rating scale at five body parts
namely the last rib, mid-flank, perineum, mid-thigh and the toe and the onset and duration of
analgesia calculated. Motor response was also evaluated in a 4-point rating scale at regular
intervals and motor blockade indices (time to recumbency and duration of recumbency)
computed.
The response rate for the survey was 74.3%. The number of dogs and cats anaesthetized per
week by veterinarians in Nairobi County were 5±3.53 and 2±1.39 respectively. Castration,
orthopedic procedures and ovariohysterectomy were the most common surgeries carried out
caudal to the umbilicus. Xylazine, ketamine and lidocaine were the most popular premedication,
induction/maintenance and local anaesthetic agents respectively. Only 17.40% of the respondents
reported to have used lumbosacral epidural anaesthesia in dogs. NSAIDs were the most preferred
analgesic agents in dogs at 50% followed by corticosteroids 25%, opioids, anxiolytics and local
anaesthetic agents each at 8.3%. Unavailability and high cost of anaesthetic and analgesic agents
as well as lack of knowledge on some drugs and anaesthesia techniques were mentioned as the
major constraints to the practice of optimal anaesthesia and analgesia in small animal practices.
Significant (P< 0.05) decrease in total erythrocyte count, total leucocyte count, packed cell
volume and hemoglobin concentration were observed following epidural injection of the six drug
regimes. Xylazine, lidocaine-xylazine, lidocaine-ketamine and xylazine-ketamine significantly
(P< 0.05) lowered heart rate in dogs. Lidocaine, xylazine, lidocaine-xylazine, lidocaineketamine
and xylazine-ketamine significantly (P< 0.05) depressed respiratory rate in dogs. | en |
