Local anaesthesia infiltration to predict failure of spinal anaesthesia in patients with history of scorpion sting-A Prospective Observational study

Work plan:

After obtaining IRC and IEC approval patients with history of scorpion sting meeting the inclusion criteria will be enrolled into the study with patients consent. Testing for resistance to local anaesthesia infiltration will be performed 30-45 mins in advance in the preoperative room. IV access will be obtained, electrocardiogram, pulse oximeter and non-invasive blood pressure will be monitored.

All patients will be pre-operatively assessed and patients with history of scorpion sting scheduled to undergo various types of elective surgeries under spinal will be given subcutaneous infiltration of local anaesthetic 0.5 ml of 0.5% Bupivacaine and the area will be marked. Resistance to local anaesthetics will be assessed by sensation to pin prick in the infiltrated area after 5 minutes. If resistance to local anaestheic is present pinprick sensation will be assessed at 10 and 15 minutes.  Patients will then be divided into 2 groups: Group R-those who have sensation to pin prick or resistance to local anaesthetics and Group L - those who have loss of sensation to pin prick.  Patients will then be shifted to Operation Theatre and preloaded with 1000 ml of RL solution, placed in lateral position and space between 3rd and 4th lumbar spine identified and marked. After taking all aseptic measures lumbar puncture will be done with 25-gauge Quincke’s spinal needle and 15mg of hyperbaric Bupivacaine 0.5% will be administered by an experienced Anaesthesiologist. Immediately, after injection of Bupivacaine patient will be placed in supine position. Electrocardiography, SpO2, heart rate and non-invasive blood pressure monitoring will be done continuously. Sensory block was assessed by pin prick with a 26 gauge hypodermic needle at 1 minute interval. The onset of sensory block was defined as the time when the patient could not feel the pain. Motor block was assessed with Bromage scale.The time for onset, level of sensory, motor block and the efficacy of sub arachnoid block will be assessed in both the groups

Those patients in whom there is partial or incomplete effect 20 minutes after subarachnoid block will be given general anaesthesia and will proceed with the surgery

Inadequate block can be partial/ unilateral/ insufficient block height or density/ inadequate duration

Those patients in whom there is partial or incomplete effect 20 minutes after subarachnoid block will be given general anaesthesia and will proceed with the surgery