STUDIES ON SONOLOCATION GUIDED BRACHIAL PLEXUS AND FEMORAL NERVE BLOCK IN CLINICAL ORTHOPAEDIC CASES
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Date
2013
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AAU, Anand
Abstract
Key words: Bupivacaine HCl (0.5%), Hyperbaric Bupivacaine HCl (0.5%), Axillary Brachial Plexus Block (ABPB) and Femoral Nerve Block (FNB). The present clinical study is carried out to evaluate the efficacy of bupivacaine HCl (0.5%) and hyperbaric bupivacaine HCl (0.5%) for axillary brachial plexus block (ABPB) and femoral nerve block (FNB) in twelve dogs and twelve goats under ultrasonographic guidance with aid of peripheral nerve stimulator (PNS) at 3.0 mg/kg b.wt. Prior to clinical study, two goats were dissected for precise anatomic location of the axillary brachial plexus and femoral nerve to augment the scrupulous result of the study and these two goats were died reason not related to this study and were brought from the department of Veterinary Pathology. The dogs and goats were sedated using butorphanol HCl at 0.1 mg/kg b.wt. and diazepam at 0.2 mg/kg b.wt. respectively prior to go for nerve blockade procedure. For convenient access, total twenty four animals were categorised into eight groups and so three in each group. For ABPB, the animals were positioned in dorsal or lateral recumbency and the axillary region was scanned by ultrasonography machine using high frequency (7.5-12 MHz) linear array transducer. The ultrasound windows produced images of axillary blood vessels and hypoechoic structures surrounded by hyperechoic rim just dorsal to the vessels and those were presumed as the nerve roots of the brachial plexus. The axillary artery as pulsatile hypoechoic structure was kept as landmark. The maximum muscle twitching at 0.4 mA current with aid of PNS made the confirmation that the needle placed was at the nearest position to the nerves of brachial plexus in all the animals and exactly at this site the local anaesthetic solution was injected at 3.0 mg/kg b.wt. and resuhed into complete blockade i.e., ptosis. The onset of the complete sensory and motor blockade in two dogs was observed at 100 minutes and in one dog at 60 minutes using bupivacaine HCl (0.5%). Similarly, the onset of the complete sensory and motor blockade in two goats was observed at 100 minutes and in one goat at 40 minutes using bupivacaine HCl (0.5%). Where using hyperbaric bupivacaine HCl (0.5%), complete sensory and motor blockade was observed at 140, 60 and 100 minutes respectively in each dog. Similarly, the onset of complete sensory and motor blockade in two goats was observed at 100 minutes and in one goat at 60 minutes. Similarly, for FNB, the animals were positioned in lateral recumbency and the inguinal region was scarmed by ultrasonography machine using high frequency (7.5- 12 MHz) linear array transducer with in-plane technique. The ultrasound windows produced images of femoral artery and vein and osseous structure was kept as landmark. Hypoechoic sti-ucture surrounded by hyperechoic rim cranial to the femoral artery was presumed as the femoral nerve. The maximum muscle twitching at 0.4 mA cuiTent with aid of PNS made the confirmation that the needle placed was at the near most position to the femoral nerve in all the animals and exactly at this location the local anaesthetic solution was injected at 3.0 mg/kg b.wt. and resulted into complete blockade. The onset of the complete sensory and motor blockade in two dogs was observed at 60 minutes and in one dog at 100 minutes using bupivacaine HCl (0.5%). Similarly, the onset of the complete sensory and motor blockade in all three goats was observed at 60 minutes using bupivacaine HCl (0.5%). Where using hyperbaric bupivacaine HCl (0.5%), onset of complete sensory and motor blockade was observed in two dogs at 100 minutes and in one dog at 60 minutes. Similarly, the onset of complete sensory and motor blockade in two goats was observed at 50 minutes and in one goat at 100 minutes. The study concluded that axillary approach for brachial plexus block and inguinal approach for femoral nerve block using ultrasonography machine along with PNS are iimovative techniques for thoracic and hind limbs to provide safe, swift and successful regional anaesthesia in dogs and goats without any complication. Bupivacaine HCl (0.5%) has more pronounced post-operative analgesia than hyperbaric bupivacaine HCl (0.5%). Hyperbaric bupivacame HCl (0.5%) takes shorter time for onset of axillary BPB and FNB as compared to bupivacaine HCL (0.5%) which was reported through assessment of sensory and motor block at specific interval in dogs and goats.
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VETERINARY SURGERY AND RADIOLOGY, A STUDY