Subarachnoid Bupivacaine in Obese Patients Undergoing Cesarean Delivery

Study Overview
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Brief Summary
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This study evaluates the effect of subarachnoid hyperbaric bupivacaine on mean arterial blood pressure (MAP) of pregnant patients with obesity undergoing cesarean section half of the patients will receive subarachnoid hyperbaric bupivacaine at a dose of 5 mg while the other half will receive a dose of 10 mg

Detailed Description
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Once the patients were admitted to the toco-surgery work area, patients over 18 years of age were captured, with pregnancy ≥37 weeks of gestation, which, based on weight and height prior to pregnancy, obesity is diagnosed with a BMI ≥30 kg / m2 and that had an indication of termination of pregnancy via abdominal caesarean section without compromising fetal well-being. Specifically, the objectives of the study protocol, benefits and risks were given and it was given to choose an envelope containing the consent letter under information, the data collection sheet and the group to which it was assigned. He was granted the consent letter under information to sign; the same procedure was performed with the husband or relative responsible for the patient They underwent pre-anesthetic evaluation, background check and review of laboratory tests, as well as taking vital signs such as non-invasive blood pressure, mean blood pressure (PAM), O2 saturation and heart rate, Fetal heart rate was taken with adult stethoscope. The administration of Hartmann solution at 10ml /kg pregestational weight and premedication with ranitidine 50 mg and metoclopramide 10 mg was informed prior to admission to the operating room In the operating room, room preparation was carried out with material for anesthesiology corresponding laryngoscope, intubation cannulas, oropharyngeal cannulas, verification of operation of anesthesia machine, verification of material of blocking equipment, needles, syringes, alcohol and iodo povidone; Verify hyperbaric bupivacaine drugs, ephedrine and atropine. In case of requiring a change in anesthetic technique, general anesthesia have necessary fentanyl opioid drugs, propofol inducer and rocuronium muscle relaxant. Preparation of emergency drugs atropine and ephedrine dilution of 1 ampoule in 10 ml of diluent solution. The patient was transferred to the operating room, baseline vital signs were taken, non-invasive blood pressure, MAP, O2 saturation and heart rate with the monitor team Simultaneously fetal heart rate was taken Permeability of peripheral pathways was verified The patient was placed in a sitting position and started with mixed technique neuraxial anesthetic anesthetic technique (placement of peridural catheter + subarachnoid block with brand blocking equipment) The anatomical reference of the intervertebral space L2-L3, L3-L4 was located in a seated position. Aseptic and antiseptic technique was performed with iodo povidone, and subsequently removed with alcohol Sterile fields were placed Skin and subcutaneous tissue were infiltrated with 2% lidocaine 5 ml of the selected intervertebral space Tuohy needle No. 17 was introduced with the Gout of Gutierrez technique, until the location was found, it was corroborated with the resistance loss technique. Through the Tuohy needle, the spinal needle whitacre pencil No. 27 was introduced until cerebrospinal fluid (CSF) was obtained. The dose of hyperbaric bupivacaine blockade of 10 mg (2 ml) or mg (1 ml) was administered agreement with the assigned group, in approximately 20 seconds; the spinal needle pencil tip whitacre and an epidural catheter was introduced with cephalic direction and left 5 cm inside the epidural space, left inert. Catheter was attached to the back with adhesive tape The patient was placed in a dorsal recumbent position with a shifting wedge placement on the right hip approximately 15 degrees to the left. Vital signs monitoring was started every 3 minutes for the first 15 minutes and then every 5 minutes until the end of the anesthetic procedure When obtaining PAM record of less than 20% at baseline, ephedrine 10 mg is administered and total doses required were recorded until PAM records were recovered above 20% of baseline. Together with the record of the first taking of vital signs, the fetal heart rate was taken again After the second vital signs were taken, (3 minutes), a sensory block evaluation was started with a puncture technique from the dermatome where the block was placed and the ascending dermatome was registered where the patient reported pain. This assessment was performed every 3 minutes for the first 15 minutes, and then every 15 minutes until the end of the surgery. The blocking level was considered adequate to initiate the surgical procedure when the loss of sensitivity in the T4 dermatome was reached. After the second vital signs were taken (3 minutes), a motor block assessment with a Bromage scale was initiated, in which the patient was instructed to make movements with her legs to assess the capacity of movement that still remains. This assessment was performed every 3 minutes for the first 15 minutes, and then every 15 minutes until the end of the surgery After the second vital signs were taken (3 minutes), the patient was asked if she had a feeling of nausea or the presence of vomiting and was registered. At the extraction of the fetus, the Apgar assessment granted by the attached neonatology doctor at one minute and at 5 minutes of extrauterine life was recorded. Once the placenta was illuminated, a sample was taken for gasometry with a heparinized syringe of the umbilical artery and sent to the laboratory for processing. A dose of local anesthetic was administered via a 5% lidocaine 2% peridural catheter if necessary, when the patient reported discomfort or pain (referred to the decrease in sensory block) and the surgical procedure has not been completed. The time at which subsequent doses are administered is recorded The information collected was recorded on the data collection sheet. The presence of adverse reactions to drugs or the anesthetic technique were recorded in the adverse event sheets. The sample size was calculated with a formula for comparison of two means with finite population. No results are found in previous publications with a statistically significant P, so a pilot test is carried out based on the specified criteria, which includes 30 patients, 15 patients in the group administered 5 mg of Subarachnoid hyperbaric bupivacaine and 15 patients in the group who were administered 10 mg of the same drug, and a standard deviation of 14.46 was obtained for the maximum blood hypotension variable recorded. For the development of the finite population formula, the total of anesthesiology procedures is quantified, the total of cesarean surgeries performed in the operating rooms of the toco-surgery of the Civil Hospital of Guadalajara Fray Antonio Alcalde in 2015; where a total of 1,218 caesarean sections are obtained y Calculated losses 25% pregnant women with obesity per group N = 40 patients. The statistical analysis was carried out once both study groups were completed. The groups were divided with the assignment codes to group 5 or 10. The database was formed in the Microsoft Office Excel 2013 program, which was exported to the statistical program Statistics Product and Service Solution (SPSS) version 22 in order to carry out the data analysis. All patients were included in the statistical analysis. The data obtained are expressed through measures of central tendency and dispersion, mean and standard deviation for quantitative variables, and frequencies and percentages in the case of qualitative variables. Due to the sample size, it is decided to use non-parametric tests for data analysis. The intra-group differences for the quantitative variables were determined by the Wilcoxon rank test, while the differences between the groups were determined with the Mann Whitney U test. Qualitative variables were analyzed through the Chi Square test. A value of p≤0.05 was considered statistically significant.

Official Title
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Effectiveness of Subarachnoid Hyperbaric Bupivacaine on Mean Arterial Blood Pressure in Pregnant Patients With Obesity Operated by Cesarean Section

Conditions
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Anesthesia, Obstetrical

Intervention / Treatment
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* Drug: Bupivacaine 5 mg
* Drug: Bupivacaine 10 mg


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients with single fetus pregnancy ≥37 weeks gestation 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: Patients with a known allergy to local anesthetics Patients with psychiatric treatment (antidepressants, anxiolytics, antipsychotics) Patients with addiction to any type of drug Patients with a history of liver disease Patients with a history of renal pathology Patients with a history of pulmonary pathology Patients with a history of cardiac pathology Patients with a history of high blood pressure Patient with a history of type I, II and gestational diabetes Non-calming fetal state Patients who refuse the anesthetic technique of neuraxial block

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 45 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Supportive Care
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Clinical trial open controlled parallel randomized simple
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Bupivacaine 5 mg<br>Receive subarachnoid hyperbaric bupivacaine at a dose of 5 mg | Drug: Bupivacaine 5 mg<br>* Receive subarachnoid hyperbaric bupivacaine at a dose of 5 mg<br>* Other names: bupivacaine/Dextrose 1ml;|
| Experimental: Bupivacaine 10 mg<br>Receive subarachnoid hyperbaric bupivacaine at a dose of 10 mg | Drug: Bupivacaine 10 mg<br>* Receive subarachnoid hyperbaric bupivacaine at a dose of 10 mg<br>* Other names: bupivacaine/Dextrose 1 ml;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Assess the mean blood pressure | Number of participants with a decrease in mean arterial blood pressure after administration of subarachnoid hyperbaric bupivacaine at a dose of 5 mg and 10 mg to preserve the mean blood pressure in pregnant patients with obesity undergoing caesarean section | 2 hours | 
| Determine the effects on the heart rate | Number of participants presenting changes in heart rate such as bradycardia (heart rate less than 60 beats minute) or tachycardia (heart rate greater than 120 beats minute) after administration of subarachnoid hyperbaric bupivacaine in the pregnant patients with obesity, after subarachnoid block | 2 hour | 
| Determine the effects on the respiratory rate | Number of participants presenting changes in respiratory rate such as bradypnea (respiratory rate less than 12 minute breaths) after administration of subarachnoid hyperbaric bupivacaine in the pregnant patient with obesity, after subarachnoid block | 2 hour | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Describe the adverse effects | Number of participants with side effects such as nausea or vomiting after administration of subarachnoid hyperbaric bupivacaine in the pregnant patient with obesity, after subarachnoid block. | 2 hours | 
| Identify the level of sensory blockade | The number of participants with adequate sensory block (thoracic dermatome 4 is defined as adequate to begin the surgical technique), the level of sensory block reached after the subarachnoid block; The sensory block was evaluated using pinprick. Every 3 minutes the first 15 minutes after the subarcnoid block. | 15 minutes | 
| Identify the intensity of motor blockade | The number of participants with adequate intensity of motor blockade achieved after subarachnoid block, the intensity of the motor block was evaluated with the bromage scale (I Free movement of legs and feet. II Just able to flex Knees with free movement of feet, III Unable to flex knees, but with free movement of feet. IV Unable to move legs or feet) Level IV was considered adequate motor block. Every 3 minutes the first 15 minutes after the subarachnoid block. | 15 minutes | 
| Measure the duration of the block | Measure the duration of the block with a dose of 5 mg and 10 mg of hyperbaric bupivacaine via subarachnoid route in pregnant patients with obesity | 2 hour | 
| Describe the adverse effects on the fetus | The number of patients with any side effect associated with the fetal bradycardia anesthetic technique (Fetal heart rate less than 120 beats minute) cardiac arrest (Fetal heart rate less than 100 beats minute) And in the newborn fetal acidosis (umbilical vein gasometry with Hydrogen Potential (pH) <7.0 or excess bases >-12 mmol/L) | 1 hour | 
| Document the Apgar score | Document the Apgar score in the newborn. (Apgar Score evaluate five sign: color, heart rate, reflex irritability, muscle tone and respiration) The score ranges from 0 to 2 per sign according to the criteria of the neonatologist, to grant a maximum score of 10 points. A grade of less than 7 points is considered low Apgar scores. This scores is registered t minute and five minutes of life. | 5 minutes | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Bupivacaine, Obesity, Pregnant, Subarachnoid, Cesarean, Subdural