Studies on epidural anaesthesia in goats

Abstract

The present study was under taken with the object of finding out the effects of epidural administration of varying doses of lidocaine hydrocaine hydrochloride two per cent solution with and without the addition of hyaluronidase in goates. Epidural injection was given at the lumbosacral site using the Brooks’ epidural needle directed perpendicularly downwards. Thirty – six apparently healthy Alpine – Malabari crossbred bucks aged six to fifteen months and weighing seven to twenty – two kilograms were used for the study. The animals were divided into two groups viz., Group 1 and Group 11, each consisting of 18 animals. In Group 1, lidocaine hydrochloride at the rate of 4 mg, 8 mg and 16 mg/kg body – weight was administered as two per cent solution in three Subgroups each consisting of six animals. Similarly in Group 11, lidocaine hydrochloride was administered as two per cent solution along with hyaluronidase (150 I.U./100 ml of lidocaine hydrochloride solution) in three Subgroup each consisting of six animals. Significant positive correlation was noticed between the depth of insertion of the epidural needle and body – weight of the animals. When the dose of lidocaine hydrochloride was increased, there was proportionate decrease in the time of onset and increase in the duration of anaesthesia. In the same dose level when hyaluronidase was added there was further reduction in the time of onset, but the duration of anaesthesia was decreased. On statistical analysis of the data, no significant difference could be seen between 1) the time of onset of flaccidity of tail and relaxation of anal sphincter 2) the duration of flaccidity of tail and relaxation of anal sphincter and 3) the time taken for assuming sternal recumbency and complete relaxation of the muscles of hind – limbs. At a dose of 4 mg/kg body – weight in both the groups, the extent of analgesia was found to be the same, irrespective of addition of hyaluronidase. At higher doses (8 mg and 16 mg/kg body – weight), the extent of analgesia was found to be more. But when hyaluronidase was added, the extent of analgesia was still further increased. ‘Dog sitting posture’ was observed during the onset of anaesthesia only at a dose of 4 mg/kg body – weight. The animals got up only when flaccidity of tail and relaxation of anal sphincter disappeared. At the dose of 4 mg and 8 mg/kg body – weight there were no untoward reactions. But at the dose of 16 mg/kg body – weight lacrimation, salivation, protrusion of tongue, locked jaw, stiffness of head and neck, pedalling movements with the fore – limbs, opisthotonos and dyspnoea were observed in some of the animals during the onset of anaesthesia. Recovery phase was uneventful in all the animals, at all the dose levels. Transient unilateral or bilateral hind – leg lameness, dullness and anorexia were noticed in some of the animals as a post – anaesthetic complication. Epidural injection of lidocaine hydrochloride, two per cent solution at the rate of 4 mg/kg body – weight is recommended for surgical operations of the hind – quarters and inguinal region, while 8 mg/kg body – weight is recommended for operations on the flank region. Hyaluronidase may be added for getting quicker onset and greater extent of analgesia.