Leg Wrapping and Norepinephrine for Prevention of Post Spinal Hypotension in C.S

Overview

Maternal hypotension after subarachnoid block is considered one of the most common complications that occurs during cesarean delivery, with an incidence of up to 70-80%. Maternal hypotension has adverse effects on both the mother and the fetus such as maternal nausea, vomiting, dizziness, cardiovascular collapse, fetal acidosis, and low Apgar scores).Hence, the prevention of spinal anesthesia-induced hypotension became a topic of great interest for clinicians as well as in literature aiming to improve maternal and neonatal safety. The main etiologies of spinal anesthesia-induced hypotension are aortocaval compression caused by a gravid uterus before delivery of the baby, blood pooling in the lower limbs, and loss of vascular tone as a result of sympatholysis during spinal anesthesia. Based on those mechanisms, Various prophylactic methods have been suggested and tried, including intravenous fluid loading, vasopressors, and physical interventions such as left lateral tilt, leg elevation, and wrapping with crepe bandage (CB). Fluid co-loading with Crystalloids is considered superior to crystalloid preloading and equivalent to colloid preloading. Despite that fluid loading decreased the incidence of hypotension, more interest was directed to vasopressors such as ephedrine, phenylephrine, and norepinephrine. Different regimens have been investigated including continuous infusion or boluses of those vasopressors with promising results reaching lower incidences of hypotension after intrathecal anesthesia but those incidences are still considerable and efforts are made to reach the optimum doses and least hypotension incidences. Lower limb wrapping with crepe bandages is a simple, non-invasive, nonpharmacological, cost-effective tool that stops blood from pooling in the lower limbs and escaping the central circulation. This method was found to decrease intrathecal-induced hypotension in cesarean delivery to incidences down to 10% in some studies. We hypothesize that the combination of a pharmacological agent as norepinephrine infusion and a nonpharmacological method as leg wrapping with crepe bandages may help in the prevention of spinal-induced hypotension during Cesarean delivery more than using only one of them.

After the local institutional ethics committee approval, all parturients scheduled for elective Cesarean section at Fayoum University Hospital starting from August 2024 will be enrolled in this prospective randomized study until the completion of the sample size. A detailed written consent will be signed by the eligible parturients before recruitment Parturients will be divided into two groups: (1) Norepinephrine Group (N), 0.05 mg/kg/min, and (2) Norepinephrine \& Leg Wrapping Group (NW) Randomization will be done using an online random number generator using a 1:1 ratio. Sequentially numbered sealed opaque envelopes will be opened with each case by an anesthesia resident not involved in patient management. Each envelope contains a code for the group to which this case belongs. The anesthesia resident will follow the instructions within each envelope, cover the lower limbs of the mother, and prepare norepinephrine infusion without further involvement in the study. Pregnant women aged more than 18 years old with a single full-term fetus, scheduled for elective cesarean delivery, will be enrolled in the study. parturients with cardiac Co-morbidities, baseline hypotension with Systolic Blood pressure (SBP) less than 100 mmHg, hypertensive disorders of pregnancy, peripartum bleeding (preoperative placenta Previa or placental abruption), and Body mass index of more than 40 kg/m2, will be excluded. Parturients with Failed intrathecal anesthesia or intraoperative bleeding of more than 500 ml of blood will be excluded from the study. All parturients will be preoperatively assessed and investigated by complete blood count, coagulation profile, Liver and kidney functions. Other investigations as serum electrolytes, ECG, Echocardiography, etc. may be ordered if needed upon case-by case assessment. Pulse oximetry, electrocardiography, and a noninvasive blood pressure cuff will be applied after arrival in the operating room. An 18-gauge cannula will be inserted peripherally, with a stopcock three-way for fluid administration and study infusion. Intravenous 20 mg of Famotidine and 1 mg of Granisetron will be given as a premedication. With the Parturient in the left-lateral tilt position, Baseline SBP will be obtained as the mean of -2-min interval- three consecutive readings. According to each envelope's instructions, the resident will use a crepe bandage (CB) to wrap both legs of the patient from the ankle up to mid-thigh. This CB will be applied with legs raised 45° either (1) loosely in group N, or (2) tightly enough that the patient feels the tightness but is still comfortable with intact capillary pulsation in the toes in group NW. Both lower limbs are then covered from midthigh downwards with surgical drapes. The resident will also prepare the study infusion: 0.5 mg norepinephrine added to 50 ml normal saline and set it to run with 0.05 mg/kg/min. Parturients will then receive intrathecal 11 mg heavy bupivacaine (2.2 ml of 0.5% w/v) with 15 µg of fentanyl by 25-G Quincke spinal needle at L3-4 or L4-5 interspace in the sitting position with rapid crystalloid co-load of 15 ml/kg. After the block, parturients will be positioned in the supine position with left lateral tilt. Pinpricks will be used to assess block success if the sensory level is at T4. The prepared infusion will be started at the same time cerebrospinal fluid is obtained by giving 1 ml bolus followed by the previously calculated rate. This infusion will be continued until five minutes after the delivery of the fetus then it will be stopped gradually over 10 minutes with a decrement decrease of 0.01 mg/kg/min every two minutes. Intraoperative hypertension (defined as an increase in SBP by more than 20% of the baseline) will be managed by temporarily stopping the infusion until systolic blood pressure returns to its normal value. Post-spinal hypotension (defined as a decrease in SBP by more than 20% of the baseline reading during the period from intrathecal injection to delivery) will be managed by 9 mg of IV ephedrine. Severe post-spinal hypotension (defined as a decrease in SBP by more than 40% of the baseline reading) will be managed by 15 mg of IV ephedrine. After two minutes another ephedrine bolus will be given if SBP is not corrected. Intraoperative bradycardia (defined as a heart rate less than 55 beats per minute during the period from intrathecal injection to delivery) associated with hypotension will be managed by 9 mg of IV ephedrine with subsequent 0.5 mg of IV Atropine if bradycardia persists while bradycardia not associated with hypotension will be managed by 0.5 mg of IV Atropine and temporary stopping study infusion until bradycardia resolves. Maternal heart rate will be monitored all through the operation while a noninvasive blood pressure reading will be taken every two minutes starting from intrathecal anesthesia until the end of the operation Co-hydration will be continued up to a maximum of 1.5 l. After delivery oxytocin will be given as a bolus of 0.5 IU over 5 seconds followed by 2.5 IU/h. Our primary outcome is the incidence of post-spinal hypotension. Secondary outcomes include the incidence of severe post-spinal hypotension, hemodynamic data including heart rate and systolic blood pressure at baseline reading and the following 15 readings, time to first hypotensive reading, number of hypotensive episodes, the total dose of ephedrine used, the incidence of hypertension, the incidence of post-delivery hypotension (defined as a decrease in SBP by more than 20% of baseline after delivery of the fetus to the end of the surgery), the incidence of tachycardia, incidence of intraoperative nausea and vomiting, Surgical time (between skin incision and delivery of the fetus), umbilical artery blood gases, and Apgar score for the neonate at 5 min after delivery.