CTRI

Spinal anaesthesia(SA) is most preferred and followed mode of anaesthesia for Caesarean section because it has immediate onset, good muscle relaxation, reduce the bleeding, protection of airway reflex and avoidance of airway intervention , postoperative analgesia and early maternal baby bonding. However, SA is associated with maternal hypotension in 80â€“83 % of parturients. Hemodynamic control during Caesarean section under SA is therefore very important for the well-being of both the mother and the fetus. Among the non pharmacological methods, wrapping lower limbs with elastic crepe bandage showed positive results with minimal requirement of pharmacological intervention for hypotension. Pharmacological methods to treat hypotension include parentral vasopressors administration. Boluses of Ephedrine and Phenylephrine have been used through time. Norepinephrine acts on alpha 1 and alpha 2 adrenergic receptors and causes peripheral vasoconstriction. It is also a weak agonist at the beta adrenergic receptors. Hence there is a recent shift to prophylactic Nor-epinephrine infusion over the use of Phenylephrine and Ephedrine in prevention and treatment of spinal induced hypotension in caesarean section. This is a randomized, double â€“ blinded triple arm trial that will be conducted in Mahatma Gandhi Medical College and Hospital between January 2018- May 2019. Parturient who are posted for elective caesarean section during this period will form the study population.Inclusion criteria will be as follows: Elective Caesarean delivery under spinal anaesthesia, American Society of Anaesthesiologists physical status 2, normotensive, term singleton pregnancy, baseline systolic BP 90-130 mm Hg, aged 18 yrs and older ,weighing between 60-90 kgs . Exclusion criteria includes patient refusal, contraindications to spinal anaesthesia, hypertension, cardiovascular or cerebrovascular disease , fetal abnormalities and diabetes(excluding gestational diabetes) and difficult venous access. Written informed consent will be obtained from all the parturients. All partuients will receive oral premedication with Tab. Ranitidine 150 mg and tab. metaclopromide 10mg on the morning of surgery. In preoperative area 15 minutes before shifting to operation theatre peripheral intravenous access will be obtained with 18G cannula and 10ml/kg ringer lactate will be infused. On arrival to the operation theatre standard monitoring will be started which include non- invasive blood pressure , ECG and pulseâ€“oximetry. Three blood pressure readings and heart rate will be measured at 3 minute interval with parturient in supine position with left lateral tilt achieved with the standard wedge under the right hip. The mean of the three recordings will be recorded as the baseline value for maternal systolic blood pressure and heart rate. A wide bore 18 G Intravenous catheter will be inserted on the other hand and kept flushed. Randomization is done by sealed envelope technique.One of the investigators who is not managing the case will prepare the study solution for infusion which will be either norepinephrine 250mcg in 50 ml at a dilution of (5mcg/ml) in 50 ml syringe or syringe containing 50 ml saline. The syringes will be labelled as study solution and will be handed over to the attending anaesthesiologist. Leg wrapping will be done in all parturients with leg elevated to 45 degree. To maintain blinding of all staff involved in patient care, after visual shielding between the head of the bed and the lower extremities leg wrapping will be performed by operational technical assistants who is trained to do this procedure. In the leg wrapping group ( Group LW), elastic bandages (12 cm Ã— 7m) will be applied tightly from the metatarsus to groin with overlap by one third between layers. In the Control group(Group C) and in the Norepinephrine group (Group NE ) , the bandage will be slackly laid around the legs. A chart containing infusion rates of the study drug according to body weight will be provided in the operating theatre and the infusion rate will be set and kept ready for infusion.Subarachnoid block (SAB) will be performed with all patients in the left lateral position. After skin infiltration with 2% xylocaine, 25 G Quinckeâ€™s needle will be inserted at L2-3/L3-4 vertebral inter-space and once free flow of cerebrospinal fluid is obtained hyperbaric bupivacaine 0.5%, 9mg (1.8 ml) will be injected intrathecally. Patients will then immediately be turned supine with left lateral tilt with wedge under right hip. Immediately following SAB, study drug infusion will be started according to body weight using a syringe infusion pump ( BBraun). Group NE will receive Norepinephrine infusion at the rate of 0.05 mcg/kg/min and the control(C) group and the leg wrapping(LW) group will receive saline infusion as per chart. The block height will be assessed by response to cold sensation using alcohol swab every minute until maximum block height was achieved. The block height of T6 will be considered appropriate. If sensory block is not achieved to T6 in five minutes the study will be terminated. Oxygen 6 L/min will be administered through polymask until delivery of the child. Blood Pressure(BP) will measured at 1 min intervals beginning immediately after spinal injection till baby delivery and at 5 minutes interval after baby delivery. Intravenous fluid will be infused at rate of 10ml/kg/hr throughout the procedure by means of volumetric pump.The study infusion rate will be maintained till the delivery of the baby according to the following protocol . If the SBP increases 25% above the baseline, the infusion will be stopped. If the blood pressure drops 20% below the baseline, 1 ml bolus of the rescue drug (inj. Norepinephrine 5mcg ) will be administered and will be repeated after every BP recording till the blood pressure improves to baseline value. If maternal HR is <50/min Inj. atropine 0.6 mg IV will given to treat bradycardia. Nausea and vomiting will be scored on a scale of 0-2 (0 =none, 1 = nausea without vomiting, 2 = vomiting). The maximum nausea and vomiting score before delivery of baby will be noted. As soon as baby is delivered,. Umbilical arterial blood sample from a segment of clamped cord will be collected with 2ml heparinised syringe and APGAR scores at 1 and 5 minutes will be noted and the study will be terminated. The data will be recorded by the anaesthetist who is conducting the anaesthesia on the preformed proforma sheet. After baby delivery Inj. Oxytocin 10 units will be infused. Study infusion will be stopped and crepe bandage will be removed at the end of the surgery. Shivering if present will be noted.