Evaluation of intravenous regional anaesthesia and four-point nerve block efficacy in the distal hind limb of dairy cows

Abstract

BackgroundIntravenous regional anaesthesia (IVRA) and hindfoot four-point nerve block anaesthesia (NBA) are recommended for local anaesthesia (LA) in the distal limb of dairy cows. Two studies were conducted to compare the efficacy, time until onset and stress responses to IVRA and NBA in dairy cows. In the first cross-over designed study, eight healthy unsedated German Holstein cows, restrained in lateral recumbency (LR) on a surgical tipping table, were treated with IVRA and NBA using procaine 2% as a local anaesthetic. Distal limb desensitization was tested by electrical (e-), mechanical (m-) and thermal (t-) nociceptive stimulation 10 min before and 15 and 30 min after LA. Hormonal-metabolic (blood concentrations of cortisol, lactate, non-esterified fatty acids, and glucose) and cardio-respiratory (heart and respiratory rate, mean arterial blood pressure) stress responses to treatment were assessed at predetermined intervals. In the second study, six healthy, unsedated German Holstein cows in LR were treated (crossover design) with IVRA and NBA. Short-interval e-stimulation was measured by the time until complete distal limb desensitization.ResultsIn the first study, four of eight cows responded to e-stimulation 15 min after IVRA, while none of the cows treated with NBA responded until the safety cut-off level was reached. E-stimulation revealed complete desensitization of the distal limb 30 min after LA in all cows. Half of the cows did not respond to m- and t-stimulation before LA, so no further evaluation was performed. Stress reactions to IVRA and NBA treatment were similar, but differences may have been masked by stress response to LR restraint. In the second study, complete desensitization was achieved 12.5 min after NBA, while one of the six cows still responded to e-stimulation 20 min after IVRA.ConclusionHindfoot nerve block anaesthesia and intravenous regional anaesthesia induced complete desensitization of the distal hind limb in dairy cows. However, the anaesthesia onset after NBA was significantly faster than that of IVRA, which may be clinically relevant in the field, particularly when distal limb anaesthesia is required for major claw surgeries under time constraints.

Distal Intravenous Regional Anaesthesia for Claw Diseases in Bovines

“…However, no significant change in respiration rate was observed in group II animals. A significant decrease in respiration rate over time after removal of tourniquet from IVRA using 2% procaine was also observed by Yavari et al (2017). No significant change in respiration rate in group II animals might be due to decreased dose used for modified IVRA.…”

“…Significant increase in heart rate in group I animals might be due to tourniquet pain. A significant (P < 0.05) increase in heart rate was also noted after IVRA (Yavari et al, 2017). Increase in heart rate may be due to restraining of animals in lateral recumbency.…”

“…Significantly low peripheral oxygen saturation might be due to lateral recumbency as rumen pressed the lungs and diaphragm. Lateral recumbency also impairs respiration in cows leading to a moderate increase in arterial pCO 2 and a decrease in pO 2 (Yavari et al, 2017).…”

“…The site was prepared aseptically and the area was painted with antiseptic solution. Intravenous regional anesthesia was induced as per the standard technique in group I animals (Yavari et al, 2017). Briefly, tourniquet was placed circumferentially in the middle of the metacarpus (Fig 1).…”

“…Distal Intravenous Regional Anaesthesia for Claw Diseases in Bovines significant increase in mean arterial pressure (MAP) was also noted after IVRA (Yavari et al, 2017). No significant change in diastolic pressure was noted in both the groups at different time intervals.…”