Antinociceptive, sedative and cardiopulmonary effects of subarachnoid and epidural xylazine-lidocaine in xylazine-sedated calves

Antinociceptive, Sedative and Excitatory Effects of Intravenous Butorphanol Administered Alone or in Combination with Detomidine in Calves: A Prospective, Randomized, Blinded Cross-Over Study

(1) Background: The diagnostic and therapeutic procedures performed under sedation or general anesthesia in bovines are numerous. The analgesic drugs that can be legally used are few, making perioperative analgesia challenging. (2) Methods: Calves were administered butorphanol 0.1 mg kg^-1 alone (SB) or combined with 0.02 mg kg^-1 of a detomidine (DB) IV. The antinociceptive effect (trigeminocervical reflex threshold (TCRt)), as well as the behavioral (sedation and excitation) and physiological (heart and respiratory rate) changes were investigated. Five time windows were defined: BL (30 min pre-injection), T1 (0-30 min post-injection (PI)), T2 (31-60 min PI), T3 (61-90 min PI) and T4 (91-120 min PI). (3) Results: Both groups had a significative increase in TCRt at T1-T4 compared to the BL. The TCRt was significatively higher in DB than in SB at T1, T2 and T4. Heart rate decreased significatively in DB compared to that in BL. Calves were significantly more sedated in the DB group, and significantly more excited in the SB group compared to the BL. (4) Conclusions: Butorphanol alone has a statistically significant antinociceptive effect, but it elicits marked excitation, limiting its clinical applicability under this dosing regimen. The co-administration of detomidine eliminated the excitatory effect and induced consistent sedation and a significantly more pronounced antinociceptive effect.

Intrathecal adenosine enhances the antinociception of Xylazine in goats

Background

The role of adenosine (AD) in neuromodulation of nociceptive signaling at the level of the spinal cord has been established in both preclinical and clinical models. Recently, the signaling pathway that involves adenosine 5-monophosphate activated protein kinase has been reported to mediate the antinociceptive effects of xylazine (XYL). The objective of this study was to investigate the antinociceptive, cardiorespiratory and hematological effects of intrathecal administration of combined XYL-AD in goats as compared to XYL alone. Six clinically healthy adult goats weighing 25 ± 2 kg were randomly assigned to one of three groups in a cross-over design. Goats were sedated with XYL (0.05 mg/kg, IM) in all groups. Ten min later, 0.9% saline solution [SAL group], XYL (0.05 mg/kg) [XYL group] or a combination of XYL (0.05 mg/kg) and AD (2000 µg) [XYL-AD group] was injected intrathecally. Antinociception scores and both cardiorespiratory and hematological parameters were measured before XYL sedation and intrathecal injection (baseline), and at 5, 10, 15, 30, 60, 90, 120 and 150 min thereafter.

Results

The XYL-AD group showed significantly earlier onset of antinociception [5 (5–7) min] than XYL [13 (12–14.25] min (P = 0.031). The duration of complete antinociception in goats that received XYL-AD was significantly longer (P = 0.031) than that received XYL alone [65 (58.75–66.25) and 47.5 (43.75–51.25) min, respectively]. In both XYL and XYL-AD groups, heart rate (HR), arterial blood pressure (SAP, MAP and DAP) were significantly decreased (P < 0.05) compared to the baseline. Compared to the SAL group, a statistically significant reduction in HR from 10 to 150 min (P < 0.05) was detected in the XYL group contrary to the XYL-AD group. Differences in the hematological parameters among different groups were insignificant.

Conclusions

AD injected intrathecally interacts synergistically with XYL to promote antinociception in goats. This discovery supports the use of AD in combination with XYL in clinical trials.

Efficacy and cardiorespiratory effects of lumbosacral intrathecal 2% procaine and 2% xylazine with or without sedation in calves undergoing umbilical surgery

Aims: To compare the effects of intrathecal anaesthesia using procaine and xylazine, with and without sedation with I/V xylazine and butorphanol, on sedation and cardiorespiratory measures in calves undergoing umbilical surgery. Methods: Male dairy calves, aged <3 months, were recruited that had enlargement of the umbilical stalk which was abnormal when palpated. They were assigned to receive either intrathecal injection between the sixth lumbar and first sacral vertebrae of 4 mg/kg of 2% procaine and 0.2 mg/kg 2% xylazine, with I/V injection of 0.02 mg/kg xylazine and 0.1 mg/kg of butorphanol (IT + SED group; n = 6), or the same intrathecal injection and I/V injection of 0.9% saline (IT group; n = 7). Surgery to correct abnormalities was carried out with calves positioned in dorsal recumbency. Rescue analgesia with injections of 2% procaine around the surgical wound was administered when movements triggered by surgery were observed. Post-operative analgesia was provided using I/V 0.5 mg/kg meloxicam. Duration of surgery was recorded, as well as degree of sedation, heart rate, systolic (SAP), diastolic (DAP) and mean (MAP) arterial blood pressure during surgery. Results: All anaesthetic and surgical procedures were successfully performed. Mean total duration of surgery was similar for the IT + SED and the IT groups (30.33 (SD 10.09) and 31.00 (SD 10.21) minutes, respectively) (p = 0.92). All calves were at least mildly sedated from 5 minutes after injections to the end of the surgery. One calf in the IT + SED group and three calves in the IT group required rescue analgesia when the umbilicus was manipulated. Between 0 and 10-15 minutes after injection, decreases in mean heart rate, SAP, MAP and DAP were observed in both groups. Mean SAP was lower in the IT + SED than the IT group. Hypotension (MAP<60 mm Hg) was present in four calves from the IT + SED group and in one from the IT group. Conclusions and clinical relevance: Intrathecal administration of 2% procaine and 2% xylazine allowed the successful completion of umbilical surgery, but 30% of calves needed rescue analgesia during surgery. Clinically, the addition of I/V sedation seemed to provide better analgesia than intrathecal block alone but resulted in greater hypotension.

Clinical effects of epidurally administered dexmedetomidine with or without lidocaine in sheep

BACKGROUND

The aims of this study were evaluate cardiopulmonary, sedative and antinociceptive effects of dexmedetomidine-lidocaine combination via lumbosacral epidural injection in sheep.

METHODS

Six Santa Inês breed sheep, 16±6 months old and weighing 42.2 ± 5.7 kg were used. Sheep were subjected to epidural anaesthesia with three treatments: L, lidocaine (1.2 mg/kg), D, dexmedetomidine (2.5 μg/kg) or DL, dexmedetomidine plus lidocaine (2.5 μg/kg + 1.2 mg/kg). Drugs were injected via pre-placed lumbosacral epidural catheters. Cardiopulmonary, arterial blood gases, electrolytes, degree of sedation and antinociceptive aspects were measured before drug administration (T0) and then at 15, 30, 60 and 120 min after drug injection (T15-T120) in all treatments and at T0 to T240 in DL.

RESULTS

There were significantly increases in PaCO₂ at times T60 and T120 in D, and at T30-T120 in DL, compared to baseline. The antinociceptive effects were observed up to 240 min in DL and 60 min in L, and were more intense in DL. Treatment D provided analgesia only in the perineal region, and only at T15.

CONCLUSION

The combination of DEX with lidocaine produced similar cardiopulmonary changes compared with either drug alone, but with greater and more prolonged antinociceptive effects.

The effects of adding epinephrine or xylazine to lidocaine solution for lumbosacral epidural analgesia in fat-tailed sheep

This blinded, randomised experimental study was designed to compare the analgesic effects of lumbosacral epidural administration of lidocaine-epinephrine or lidocaine-xylazine combinations in fat-tailed sheep. Nine healthy fat-tailed male lambs (mean ± s.d. age, 4.6 ± 0.4 months; weight, 24.6 kg ± 2.5 kg) were randomly allocated into four groups of six sheep: lidocaine 2% (LID), lidocaine-epinephrine 5 µg/mL (LIDEP), lidocaine-xylazine 0.05 mg/kg (LIDXY) or bupivacaine 0.5% (BUP). The onset and duration of flank, perineum and hindlimb anaesthesia and the onset and duration of hindlimb paralysis were recorded. Epidural administration of LID, LIDEP, LIDXY or BUP produced anaesthesia within 6.6 min, 7.6 min, 3.4 min and 8.4 min, respectively. The mean onset of anaesthesia in the LIDXY group was significantly shorter compared with the BUP group (p = 0.02). The mean duration of anaesthesia was 107.9 min, 190.4 min, 147.6 min and 169.7 min for LID, LIDEP, LIDXY and BUP, respectively. The onset of hindlimb paralysis was faster in the LIDXY group than in the BUP group; however, the duration of hindlimb paralysis was shorter in LIDXY compared with LIDEP. Epidural administration of LIDEP or LIDXY provides a comparable duration of local anaesthesia without any adverse effects in fat-tailed sheep. Epidural LIDXY did not appear to be advantageous over epidural LIDEP.