Efficacy of level adjusted local anaesthetic dose for subarachnoid block in elective caesarean section -A randomised trial.

All parturients  of category IV will be  pre-medicated with tablet pantoprazole 40mg and  tablet perinorm 10mg night before and morning of surgery. Parturients belonging to category III will receive oral pantoprazole 40 mg two hours prior to surgery. A 18 gauge intravenous cannula will be inserted and standard monitoring such as non-invasive blood pressure ,saturation and ecg will be established. The base line vitals will be recorded. The patient will then be placed in lateral position. Pre-procedural ultrasound scanning will be done to identify the respective interspace. Then subarachnoid blockade will be administered using 25 g quincke’s needle in group A with 2ml of 0.5% hyperbaric bupivacaine in L2-L3 space , group B with 2.2ml of 0.5%bupivacaine in L3-L4 space, in group C 2.4ml of 0.5%bupivacaine in L4-L5 space. Drug will be loaded in 2.5ml syringe and will be administered at the rate of 0.2ml/sec. All the patients will be coloaded with intravenous crystalloids at 15ml/kg after the administration of intrathecal bupivacaine. Then patient will be placed in supine position. Wedge will be placed for all patients. Supplemental oxygen will be given with face mask at 6l/min. Sensory block assessment will be done with pinprick method and motor assessment will be done by bromage assessment. Desired spinal level is T4-T6. Manoeuvres required to achieve the spinal level such at head down(Trendelenburg position) will be noted. Time taken to achieve the desired level will also be noted. Hemodynamic parameters will be measured at 0,1,2 minutes  and  there after every 2 minutes for the first 15minutes. Then after every 5minutes till the end of surgery. 0 minute is defined  as the time of removal of spinal needle. Surgery will be proceeded and after the delivery of the baby 20 international units of oxytocin intravenously will be administered. Delivery time , weight and apgar score of the baby will be noted. Hypotension is defined as 20% decrease in blood pressure from the baseline or systolic blood pressure less than 90mmhg. Bradycardia is defined as 20% decrease in heart rate from baseline or less than 50 beats/minute. Hypotension will be treated with intravenous ephedrine 6mg bolus dose and total dose required will be noted. Bradycardia will be treated with intravenous atropine 0.6mg and will be noted. Incidence of dizziness, nausea and vomiting due to maternal hypotension will also be noted. At the end of surgery blood loss and total intravenous crystalloids used will be noted. All patients will receive 2 mcg/kg of intravenous fentanyl after the delivery of the baby and intravenous paracetamol1g during skin closure. Patients who require more than three attempts for spinal anaesthesia and patients with insufficient sensory blockade at the end of 10mins, general anaesthesia will be administered and patients will be excluded from the study.By using the ultrasound ,the space cannot be identified,then the patient will be excluded from the study.