Those patients who received subarachnoid block under strict aseptic precautions through midline approach at L3-L4 interspinous space with 25 gauge Quincke-Babcock spinal needle using 3 ml of 0.75% heavy Ropivacaine administered at the rate of 0.2 ml/sec will be taken up for the study. The time of intrathecal drug injection will be noted as time “0” The patients who are made to lie down immediately after giving spinal anaesthesia will be considered as group A. The patients who are made to sit for 1 minute before positioning them supine after giving spinal anaesthesia will be considered as group B. The decision to position the patient after injection of the spinal drug will be of the consultant anaesthesiologist in charge. Sedation will be given as per the institutional protocol.

Following parameters will be assessed:

1. Onset of anaesthesia will be considered when loss of sensation is achieved at L1 dermatome level. Sensory block will be assessed by cold spirit swab method along midclavicular line bilaterally every 2 minutes until 10 minutes, there after every 5 minutes until 30 minutes. The highest dermatome showing sensory analgesia will be taken as the upper segmental level of the block when it remained the same even after 5 minutes. Sensory blockade at the time of shifting from operation theatre will be noted. Duration of sensory block will be considered as from the onset of the block till the patient complains of pain.

2. The motor block of both lower limbs will be assessed using the Modified Bromage Scale every 2 minutes before the onset of the surgery. Onset of motor blockade will be considered when the patient is not able to move feet or knees (modified Bromage grade 3 score). The duration of motor block will be taken as the time from full intensity motor blockade until a Modified Bromage grade 0 score is achieved. 

3. Hemodynamic changes - The changes in heart rate, systolic and diastolic blood pressure and blood oxygen saturation will be recorded

a) every 2 min for first 20 min

b) there after every 5 min for 60 min

c) at 30 min intervals up to 300 min after subarachnoid block

● Hypotension will be defined as a decrease to MAP< 65 mmHg, treated with IV bolus of 6 mg Inj. Ephedrine and 100 ml of Ringer lactate.

● Bradycardia will be defined as HR < 40 beats/min and treated with Inj. Atropine 0.6 mg IV bolus.

● Desaturation is defined as SpO2< 92% and treated with 6 L oxygen per minute.

4. Duration of anaesthesia will be assessed from the time of onset of the anaesthesia till the patient complains of pain postoperatively.

5. Any complications during the procedure will be noted.

(1) Inadequate spinal anaesthesia requiring either repeating the intrathecal drug, or converting to general anaesthesia

(2) Inadequate duration of anaesthesia requiring supplementation of analgesia

(3) Bradycardia and hypotension due to other reasons like blood loss.

(4) Nausea and vomiting

6. Number of times vasopressors, Inj. Ephedrine 6mg IV bolus and Inj. Atropine 0.6mg IV bolus given will be noted.