Effects of xylazine, lignocaine and their combination for lumber epidural analgesia in water buffalo calves (Bubalus bubalis).
The study was conducted to evaluate the effects of xylazine alone (0.05 mg/kg), lignocaine alone (2.0 mg/kg) and a combination of xylazine and lignocaine (0.05 mg/kg and 2.0 mg/kg, respectively) after lumbar epidural administration in water buffalo calves. Fifteen nondescript, male water buffalo calves of 6-8 months of age and weighing between 55 and 75 kg were randomly placed in 3 groups (A, B and C). The agents were administered at the 1st lumbar epidural space. Clinico-physiological parameters such as analgesia, ataxia, sedation, salivation, heart rate, respiratory rate and rectal temperature were studied. Other haematological and biochemical parameters monitored were haemoglobin, packed cell volume, total leukocyte count, plasma glucose, cortisol, protein albumin, globulin, blood urea nitrogen, creatinine, ALT, sodium, potassium and chloride. The onset of analgesia was faster in group C (3.0 +/- 0.44 min) compared with that of group B (4.4 +/- 0.40 min) and group A (34.0 +/- 1.86 min). Analgesia of the thorax, flank, inguinal region, hind limbs, perineum and tail was complete in group C, but mild to moderate in groups A and B. Ataxia was severe in groups B and C and mild in group A. Mild to deep sedation were produced by groups A and C animals. Longer duration and greater depth of analgesia was produced in animals in group C. Heart rate, respiratory rate and rectal temperature decreased in groups A and C. The haematological parameters decreased in all the groups. The biochemical parameters like glucose, cortisol, blood urea nitrogen, creatinine, ALT increased in all the animals. However, total proteins and albumin decreased in the 3 groups. The plasma electrolytes sodium, potassium and chloride did not show any significant change. The results of this study indicated a possible additive analgesic interaction between epidurally administered xylazine and lignocaine, without causing any marked systemic effects in water buffalo calves.
Uptake and Elimination of Local Anesthetics during Spinal Anesthesia
The pharmacokinetics of spinal anesthesia involves three phenomena: distribution of local anesthetics within cerebrospinal fluid (CSF); uptake of local anesthetics into tissues within the subarachnoid space; and elimination of local anesthetics from the subarachnoid space. The present review considers only uptake and elimination. The object is provision of neither an encyclopedic review nor an annotated bibliography, but rather, selective analysis of published materials for the development of principles and concepts important in clinical anesthesia.
Blood concentration of lidocaine after spinal anaesthesia using lidocaine and lidocaine with adrenaline.
In 32 patients undergoing spinal anaesthesia with lidocaine or lidocaine plus adrenaline, the concentration of lidocaine base was measured in repeated venous blood samples. Half of the patients were given 100 mg lidocaine alone and the other half 100 mg lidocaine with the addition of 0.2 mg adrenaline. The blood concentration of lidocaine was significantly higher in the lidocaine group than in the group that received lidocaine with adrenaline. The mean maximal concentrations in these two groups lay between 0.2 and 0.3 and between 0.1 and 0.2 micrograms/ml, respectively (P less than 0.01). The time required for the individual maximal concentration to be reached was independent of whether the anaesthetic contained adrenaline or not. The blood concentration showed no correlation to body weight, height, or body surface area. In the first 60 min after the spinal injection the extent of the sensory block was the same in the two groups, but at 120 min this extent was significantly greater in the lidocaine-adrenaline group (P less than 0.01). The results show that the blood concentration of lidocaine is low in spinal anaesthesia compared with other types of regional anaesthesia.