Effect of meloxicam coadministration on the anaesthetic potency of thiopental sodium in a chick model

Few studies have dealt with thiopental sodium-induced anaesthetic action and the effect of combining meloxicam (a high plasma protein-bound) in 10–15 day old chicks. First, the analgesic median effective dose (ED50) was determined as 35.85 mg/kg, IM by up-and-down routine, while the hypnotic ED50 value was 34.40 mg/kg, IM in the chick model. A thiopental sodium injection (18, 36 and 72 mg/kg, IM) produces a significant dose-responsive hypnotic effect in chicks, determined by the beginning of the lack of a righting reflex, duration and recovery time. Thiopental sodium and meloxicam (72 and 1 mg/kg, IM) in combination shortened the beginning of hypnosis, and significantly extended its duration, with a significant increase in recovery time from the hypnotic effect when compared to the group receiving only thiopental sodium. The same combination also elicited a significant increase in the analgesic percentage and efficacy, and significant increase in the voltage current estimated via using electrical stimulation to induce the ache feeling. No significant changes were found in the concentrations of serum glutamate pyruvate trans-aminase (GPT), glutamate oxalo-acetate trans-aminase (GOT) with body temperature between the two groups, with the exception of a significant change in respiratory rate. The outcomes of this study support the prospect of using thiopental sodium as an anaesthetic agent for veterinary surgical procedures in the chicks, in combination with meloxicam, to produce worthy, consistent, and proficient anaesthesia.

Levobupivacaine versus racemic bupivacaine: a comparative study on spinal anaesthesia in lower limb surgeries

Background: This study aims to compare the anaesthetic potency of intrathecally administered levobupivacaine with racemic bupivacaine in lower limb surgeries.Methods: 60 adult cases ranging in age from 18 to 60 years with ASA Grade I and II, presenting for elective lower limb surgery were randomly allocated into two groups containing 30 cases each. Cases in Group L received 3ml of 0.5% levobupivacaine and those in Group R received 3ml of 0.5% levobupivacaine.Results: Cases in both groups showed similarity and no statistically significant differences were observed. Cardiovascular parameters were stable and similar between both groups.Conclusions: Levobupivacaine and racemic bupivacaine show equally effective potencies for spinal anaesthesia in lower limb surgeries.

Labour analgesia: choice of local anaesthetics

In this chapter, the rationale for the choice of commonly used local anaesthetics—racemic bupivacaine, ropivacaine, and levobupivacaine—is reviewed, particularly with respect to their potency and differential block. Epidural and spinal dosing for labour analgesia and the role of ‘up–down’ studies to determine the minimum local anaesthetic concentration (MLAC) for labour analgesia is explained. Applying the MLAC model has enabled clinical comparisons at equipotent concentrations and doses. It has also quantified what contribution opioids have on the overall effectiveness of the analgesic mixture, provided a means of optimizing combinations of local anaesthetic–opioid solutions, examined the effect of inter-individual and obstetric variables on local anaesthetic potency, and provided a pharmacological-based rationale for analgesia solutions used for labour analgesia.

Anaesthetic potency and physiological effects of refrigerated solution of thiopentone sodium in rabbits

Several in vitro studies have justified the use of thiopentone solutions beyond the period recommended by the manufacturer. We conducted this in vivo study to investigate the anaesthetic potency and physiological effect of refrigerated thiopentone solution. Rabbits in four groups designated A, B, C and D were anaesthetized using 25 mg/kg thiopentone solution stored for 0 (fresh solution), 3, 7 and 14 days in the refrigerator. Anaesthetic potency of the thiopentone solution was determined by monitoring the durations of anaesthesia and recovery time while its physiological effect was assessed by evaluating the changes in the heart and respiratory rates, packed cell volume and blood glucose post injections. The durations of anaesthesia and recovery time in group A were significantly (P < 0.05) longer than those obtained in groups B, C, and D. At 20 min during anaesthesia, heart rates of rabbits in group A and B were significantly (P < 0.05) lower than heart rates of rabbits in group C. Respiratory rates decreased significantly (P<0.05) in the four groups post induction of anaesthesia. Packed cell volumes (PCV) in all groups decreased significantly (P<0.05) by 10 min post induction while PCV of the groups increased at 30 and 60 min. In the four groups, no significant increase (P>0.05) in blood glucose occurred at 10 min post induction while blood glucose decreased significantly (P<0.05) at 60 min post induction. Our findings showed that the potency of thiopentone solution decreased with refrigeration. Also significant drop in blood glucose of rabbits occurred post thiopentone injection. Based on these findings, we discourage the use of refrigerated solutions of thiopentoneKeywords: Glucose, Rabbits, Refrigeration, Respiratory rate, Thiopentone sodium