A patient posted for vaginal hysterectomy was administered subarachnoid block, which failed, so was repeated in one space above. The block failed again, after waiting for 30 min. Patient gave a history of scorpion bite twice, once at the age of 17 years on her right foot and again about 8 months back. Thereafter, balanced general anaesthesia was given. On eighth post-operative day, after explaining about her possible special condition (?Resistance to local anaesthetic agents), the patient was given left median, ulnar and radial nerve blocks at the wrist and local infiltration near the anatomical snuff box. There was neither sensory nor motor block. The scorpion venom is known to affect the pumping mechanism of sodium channels in the nerve fibres, which are involved in the mechanism of action of local anaesthetic drugs, it may be responsible for the development of ‘resistance’ to the action of local anaesthetic agents.

Background:During the routine practice in the institution, it was observed that there were persistent incidents of inadequate/failed spinal anaesthesia in patients with a history of single or multiple scorpion bite/s. To test any possible correlation between scorpion bite and the altered response to spinal anaesthesia, a case control study was conducted involving patients with a history of scorpion bite/s and without such a history.Methods:Randomly selected 70 (n=70) patients of either sex and age range of 18-80 years, were divided into two equal groups, giving past history of one or multiple scorpion bites and giving no such a history. The anaesthetic management was identical inclusive of subarachnoid block with 3.5 ml. 0.5% bupivacaine heavy. The onsets of sensory, motor and peaks of sensory and motor blocks were observed with the pin-prick method and Bromage scale. After waiting for 20 min, if the block was inadequate, then balanced general anaesthesia was administered. The analysis of the data and application of various statistical tests was carried out using Chi-square test, percentages, independent sample t-test and paired t-test.Results:Demographically both groups were comparable. In scorpion bite group, the time of onsets of both sensory and motor blocks and time for the peak of sensory and motor blocks were significantly prolonged, 4 patients had failed/inadequate sensory block and 5 patients had failed/inadequate motor block while all the patients in non-bite group had adequate intra-operative block.Conclusion:We conclude that there appears to be a direct correlation between the histories of old, single or multiple scorpion bites and development of resistance to effect of local anaesthetics administered intra-thecally.

Background and Objectives:The purposes of this study were to evaluate the onset, quality and duration of sensory and motor blockade between hyperbaric bupivacaine and clonidine combination with bupivacaine alone when administered intrathecally for unilateral spinal anesthesia in below-knee orthopedic surgery, efficacy of clonidine for post-operative analgesia and side-effects of clonidine, if any.Methods:Sixty ASA I and ASA II patients scheduled for elective surgery with time duration up to 90 min were studied. Patients were randomised in two equal groups by the lottery method. Group A (control group) was given Inj. bupivacaine (hyperbaric) 0.5% - 12.5 mg (2.5 ml) + 0.5 ml of normal saline intrathecally. Group B (clonidine group) was given Inj. bupivacaine (hyperbaric) 0.5% - 12.5 mg (2.5 ml) + 50 mcg clonidine in 0.5 ml volume intrathecally.Results:The mean peak sensory block was earlier in Group B (4.7±1.23 min) as compared with Group A (6.27±1.51 min). The mean peak motor block was earlier in Group B (6.17±1.20 min) as compared with Group A (8.63±1.71 min). The two-segment regression of sensory block was longer in Group B (106.23±9.17 min) as compared with Group A (104.43±17.75 min), which is clinically significant. Requirement of rescue analgesia was considerably prolonged in Group B (450.33±95.10 min) as compared with Group A (220±36.36 min), which was also clinically highly significant.Conclusion:Intrathecal clonidine potentiates bupivacaine induced spinal sensory block and, motor block and reduces the analgesic requirement in the early post-operative period in unilateral spinal anesthesia for lower limb below knee surgery.

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