Effect of Subarachnoid Hyperbaric Bupivacaine in Obese Pregnant Patients Undergoing Cesarean Section

Effect of Subarachnoid Hyperbaric Bupivacaine on Mean Arterial Pressure in Obese Pregnant Patients Undergoing Cesarean Section

Evaluates the effect of hyperbaric subarachnoid bupivacaine at doses of 5 mg vs 10 mg on mean arterial pressure in obese pregnant patients undergoing cesarean section

Patients over 18 years of age, with a pregnancy of ≥37 weeks of gestation and adequate fetal well-being, with obesity with a BMI ≥30 kg/m2 presented for cesarean surgery will be included in the study. The objectives of the study protocol, benefits, and benefits will be explained to them. and risks and by election by sealed envelope will be assigned to one of the two study groups, they will be given to sign the consent letter under information. They underwent pre-anesthetic evaluation, baseline vital signs: non-invasive blood pressure, mean arterial pressure (MAP), O2 saturation and heart rate, fetal heart rate will be recorded from the fetal monitor. A preload of Hartmann's solution fluids at 10ml/kg of pre-pregnancy weight and premedication with omeprazole 40mg and metoclopramide 10mg will be administered. Once inside the operating room, baseline vital signs will be recorded and the placement of anesthesia with mixed technique neuraxial block (epidural catheter placement + subarachnoid block) will begin in a sitting position, the anatomical reference of the intervertebral space L2-L3, L3- will be located. L4. The aseptic and antiseptic technique with povidone-iodine and alcohol will be performed on the skin, sterile fields will be placed, the skin and subcutaneous tissue will be infiltrated with 5 ml of 2% lidocaine, a Tuohy No. 17 needle is inserted with the "hanging Drop" technique, to locate the epidural space, it was corroborated with the "loss of resistance" technique. Through the "Tuohy needle", the "spinal needle" No. 27 spinal needle is inserted until cerebrospinal fluid (CSF) is obtained. The blocking dose of hyperbaric bupivacaine of 10 mg (2 ml) or mg (1 ml) will be administered according to the assigned group; The "spinal needle" was withdrawn and the epidural catheter was inserted in a cephalic direction, leaving 5 cm inside the epidural space. The catheter was fixed to the skin with adhesive tape for later use. The patient will be placed in the supine position and a position is given with the surgical table 30 degrees to the left. Vital sign monitoring was started every 3 minutes for the first 15 minutes and then every 5 minutes until the end of the procedure. When a MAP record of less than 20% is obtained at the beginning, 10 mg ephedrine will be administered, an evaluation of the sensory block will begin 6 minutes after administering the block dose, with the prick technique, this evaluation will be It will be performed every 3 minutes during the first 15 minutes and then every 15 minutes until the end of the surgery. Simultaneously, an assessment of motor blockade will begin with a Bromage scale. After taking the second vital signs (3 minutes), the patient will be asked if she feels nauseated or if she vomits and it will be recorded. At the time of the extraction of the fetus, the Apgar score given by the neonatologist at one minute and at 5 minutes of extrauterine life will be recorded. Once the placenta has been delivered, a sample for gasometry will be taken with a heparinized syringe from the umbilical artery and sent to the laboratory for processing. A dose of local anesthetic will be administered through a 5% to 2% lidocaine epidural catheter if the patient reports discomfort or pain and the surgical procedure has not been completed. The information collected will be recorded in the data collection sheet. The sample size was calculated with a formula for comparing two means with a finite population.A pilot test was carried out with the specified criteria, which included 40 patients, 20 patients received 5 mg of subarachnoid hyperbaric bupivacaine and 20 patients received 10 mg, for the maximum arterial hypotension variable registered a standard deviation of 16.87 was obtained. The finite population was obtained by registering the total cesarean sections of the Civil Hospital of Guadalajara performed during the year 2022, which were 1,256 cesarean sections and losses of 20% are calculated, obtaining a total of 53 patients per group with a total of 106 patients. Once the sample is completed, the database will be started in the Microsoft Office Excel program, which will be exported to the statistical program Statistics Product and Service Solution (SPSS) for statistical analysis. The data obtained will be expressed through measures of central tendency and dispersion, mean, minimum, maximum, median and standard deviation for quantitative variables, and frequencies and percentages in the case of qualitative variables. The intragroup differences for the quantitative variables were performed using the Student's T test, differences between the groups were determined with the U Mann Whitney test. Qualitative variables will be analyzed with the Chi Square test. A value of p≤0.05 is considered statistically significant.

Inclusion Criteria:

• Pregnancy ≥37 weeks gestation with single fetus
• Body mass index (BMI) ≥ 30 kg/m2
• Indication of termination of pregnancy via abdominal caesarean section
• Indication of subarachnoid neuraxial block under mixed technique
• Signing of consent under information

Exclusion Criteria:

• Allergy to local anesthetics
• Psychiatric treatment (antidepressants, anxiolytics, antipsychotics)
• Addiction to any type of drug
• Liver, renal, pulmonary or cardiac disease
• High blood pressure
• Type I, II and gestational diabetes
• Diagnostic of non-calming fetal state