In orthopedic surgery providing optimal analgesia throughout the perioperative period decreases physiologic stress, optimizes tissue healing and reduces reconvalescence and overloading of the contra-lateral limb. We hypothesized that continuous peripheral nerve block (CPNB) of the median and ulnar nerve provides a valuable method of sustained analgesia in horses experiencing pain in their lower forelimbs. Therefore we developed an ultrasound-guided technique for continuous ulnar and median nerve blockade and determined the antinociceptive effects of local anesthetic infusion. Feasibility and efficacy of CPNB was tested in 12 standing, sedated horses after prior technique development in 37 forelimb specimens. Six horses were instrumented bilaterally and received 5-15 mL boluses of drug solution per catheter site followed by 0.5-2 mL/hr CRI over a 6-day period. One forelimb received bupivacaine 0.5% [BUP], while the contra-lateral NaCl 0.9% [SAL], serving as a control. Solutions contained epinephrine 5 microliter/mL. Anatomical landmarks, needle insertion and catheter suitability (polymer, stainless steel coil-armored, 19 G), and skin fixation satisfactoriness were established. Infusion of BUP but not SAL increased significantly the thresholds of electrically or mechanically evoked hoof withdrawal responses (HWR) and prolonged HWR latencies (P< 0.05). Catheters were well tolerated for 6-10 days. Microbial contamination was detected in 8/22 CPNB catheters after their removal, with primarily environmental bacteria. This new technique can be successfully applied under ambulatory conditions in the standing horse without major complications but additional studies are warranted to prove its superiority over other analgesic treatments.
Ultrasound-guided technique for continuous ulnar and median nerve blockade in the horse
ZARUCCO, Laura;
2008-01-01
Abstract
In orthopedic surgery providing optimal analgesia throughout the perioperative period decreases physiologic stress, optimizes tissue healing and reduces reconvalescence and overloading of the contra-lateral limb. We hypothesized that continuous peripheral nerve block (CPNB) of the median and ulnar nerve provides a valuable method of sustained analgesia in horses experiencing pain in their lower forelimbs. Therefore we developed an ultrasound-guided technique for continuous ulnar and median nerve blockade and determined the antinociceptive effects of local anesthetic infusion. Feasibility and efficacy of CPNB was tested in 12 standing, sedated horses after prior technique development in 37 forelimb specimens. Six horses were instrumented bilaterally and received 5-15 mL boluses of drug solution per catheter site followed by 0.5-2 mL/hr CRI over a 6-day period. One forelimb received bupivacaine 0.5% [BUP], while the contra-lateral NaCl 0.9% [SAL], serving as a control. Solutions contained epinephrine 5 microliter/mL. Anatomical landmarks, needle insertion and catheter suitability (polymer, stainless steel coil-armored, 19 G), and skin fixation satisfactoriness were established. Infusion of BUP but not SAL increased significantly the thresholds of electrically or mechanically evoked hoof withdrawal responses (HWR) and prolonged HWR latencies (P< 0.05). Catheters were well tolerated for 6-10 days. Microbial contamination was detected in 8/22 CPNB catheters after their removal, with primarily environmental bacteria. This new technique can be successfully applied under ambulatory conditions in the standing horse without major complications but additional studies are warranted to prove its superiority over other analgesic treatments.
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
