patients will be divided randomly into three groups (A, B, C) of 25 each, according to computer generated table of random numbers.
- Patients in group A will receive 3 mg/kg of lidocaine 2% diluted with saline to a total volume of 40 ml.
- Patients in group B receive 3 mg/kg of lidocaine 2% + 2 mg atracurium diluted with saline to a total volume of 40 ml.
- Patients in group C will receive 3 mg/kg of lidocaine 2% + 2 mg atracurium mixed with 10 mg /kg magnesium sulphate diluted with saline to a total volume of 40 ml.
Onset of sensory block will be assessed by a pin prick performed at 1 minute interval in the dermatomal sensory distribution of the medial and lateral ante brachial cutaneous, ulnar, median and radial nerves. Sensory block onset time will be recorded as time elapsed from injection of drug to sensory block achieved in all dermatomes.Onset of motor block will be assessed by asking the subject to flex and extend his/her wrist and fingers. Monitoring of motor block will be assessed by Modified Bromage Score . Complete motor block will be recorded when no voluntary movement will be possible.
At the end of surgery, the tourniquet will be deflated by a cyclic deflation technique and recording this :
- Sensory block recovery time
- Motor block recovery time
- Mean arterial pressure (MAP),
- heart rate (HR)
- visual analogue scale (VAS) will be recorded at 0, 15 min , 1, 6, 12, and 24 h.
- The time to first analgesic requirement will be recorded (the time elapsed from tourniquet release until first patient request for analgesic).
Patient and surgeon satisfaction