Is Elective Caesarean Sections for Predicting Post-spinal Hypotension Role of Overactive Bladder?
Condition: 18-45 Range of Age; Cesarean Section; Primigravid
MeSH terms: Urinary Bladder, Overactive; Hypotension
Study type: Interventional

Summary: 
      It is to predict postspinal hypotension that may develop in patients diagnosed with
      overactive bladder who will undergo elective cesarean section under spinal-epidural
      anesthesia.
    

Detailed description: 
      INTRODUCTION

      Spinal anesthesia is the most preferred standard anesthesia technique in caesarean sections.
      After a C-section, hypotension develops in approximately 70% of pregnant women and 33% of
      nonpregnant women and this situation is generally more severe and sudden in pregnant women.
      Aortocaval compression and low basal vasomotor tone caused by the Gravid Uterus and
      sympathetic blockade associated with spinal anesthesia contribute to this sudden onset and
      deep hypotension. Serious post-spinal hypotension that is not properly treated can increase
      the risks of maternal and fetal complications. It is important to identify patients at high
      risk of developing hypotension. Because it will enable us to manage the process more
      proactively.

      Many predictive methods such as thoracic electrical bioimpedance, heart rate (HR)
      variability, pupillary light reflex analysis, and perfusion index (PI) were used to predict
      the onset of hypotension. In some studies, it has been shown that hypotension may develop
      with disruption of the balance between sympathetic and parasympathetic nervous systems in the
      autonomic nervous system.

      The bladder is an organ in which the sympathetic and parasympathetic system works in
      coordination. For a normal micturition, the balance between the sympathetic and
      parasympathetic systems should not be disturbed. Overactive bladder (OAB) is a syndrome that
      includes symptoms such as sudden and severe urination, urge to urinate suddenly, incontinence
      before reaching the toilet, and frequent urination (≥8 per day). Overactive bladder can be
      diagnosed based on subjective symptoms instead of urodynamic tests. In our country, the rate
      is 20% for males, 35.7% for females and 29.3% for both sexes. The main problem here is the
      balance disturbed between the sympathetic and parasympathetic systems.

      Our primary goal in the study is to predict post-spinal hypotension that may develop in
      patients with a diagnosis of the overactive bladder who will undergo elective cesarean under
      combined spinal epidural anesthesia.

      MATERIALS AND METHODS

      These randomized triple-blind prospective studies will be performed on the primiparous
      pregnant woman in ASA I-II, 2nd and 3rd trimester, who will undergo an elective caesarean
      under combined spinal epidural anesthesia after obtaining informed written consent from
      patients and the ethics office of Medicine Research Hospital of Atatürk University. Exclusion
      criteria: ≤18 or ≥45 years of age, emergency obstetric surgery, pregnancy-induced
      hypertension, significant systemic disease, multiple pregnancy, fetal or placental
      abnormality, hypersensitivity or allergy history to drugs to be used in the study, morbid
      obesity (BMI≥40), autonomic neuropathy, diabetes, patients with contraindications to
      neuraxial anesthesia, multigravida, urinary tract infection, and Cre≥1.2, who are unable or
      unwilling to participate in the study will be excluded. Patients diagnosed with OAB will be
      classified as Group I and other patients will be classified as Group II. Patients will be
      randomly assigned to Group I and Group II. For this, a random number table will be used.

      ANESTHESIC MANAGEMENT

      After patients have transferred to the operation room, an intravenous (iv) access is obtained
      with an applicator size of 20, and routine monitorization consisting of electrocardiogram
      (ECG), peripheral oxygen saturation (SpO2), and non-invasive blood pressure is performed.
      While the patient is in the supine and lateral tilt positions, blood pressure and heart rate
      will be measured 2 times consecutively and the average of these values will be recorded as a
      baseline value. From the beginning of spinal anesthesia to the end of surgery Isolyte S will
      be infused at room temperature with 10 mL/kg / h speed to patients. According to our
      institutional protocol, intravenous (iv) hydration will not be given as preload, and
      afterload and vasopressor infusion will not be initiated before spinal anesthesia. After the
      skin is prepared sterile and local infiltration with 2% lidocaine is done, from L3-L4 OR
      L4-L5 range on midline with the 16 gauge Tuohy needle, and the loss of resistance technique
      epidural space is identified and then 26 gauge pencil point needle is passed trough the Touhy
      and the dura will be drilled. After the cerebrospinal fluid (CSF) is seen the fluid
      containing 5mg isobaric bupivacaine and 15µg fentanyl will be given in 30 seconds to
      patients. After the spinal needle is removed, the epidural catheter is placed 3-5 cm in the
      epidural space through Tuohy, and after the catheter is fixated, the patients will be placed
      in the supine position by placing a height under their right hip with a 15 ° angle. Blankets
      will be used to maintain the body temperature of patients and all fluids used during surgery
      will be delivered at 24 ° C. Oxygen will be given to patients at 4l / min with a face mask
      throughout the operation.

      OVERACTIVE BLADDER DIAGNOSIS

      The presence of OAB for each patient in the primipara who applied in the second and third
      trimesters will be determined using the Turkish version of OAB-V8, which consists of eight
      questions that can be graded on a 6-point scale ranging from 0 to 5; 0 (not at all), 1 (a
      little bit), 2 (somewhat), 3 (quite a bit), 4 (a great deal) and 5 (a very great deal). The
      lowest total score will be 0, the highest total score will be 40, and those with a higher
      score than 11 will be evaluated in favor of OAB. With the OAB-V8 form, a non-invasive
      uroflowmetry test will be applied to pregnant women, and tower-like diagram will be
      interpreted in favor of OAB.

      STUDY PROTOCOLS

      After the spinal anesthesia has been performed in the following first 10 minutes blood
      pressure and heart rate will be measured in every minute after the first 10 minutes will be
      measured in every 2.5 minutes until the baby is born. Hypotension will be defined as symptom
      complaints compatible with hypotension (ex: paleness, dizziness, shortness of breath, nausea
      or vomiting) without the systolic blood pressure falling below 20% or systolic blood pressure
      below 20% of the basal value. If hypotension occurs, it will be treated with ephedrine until
      blood pressure reaches baseline (initial dose 10 mg, intravenously) and rapid colloid or
      crystalloid infusion. If hypotension persists or recurs, vasopressor treatment will be
      repeated every 1 minute. Bradycardia will be described as having a heart rate of 50 beats/min
      and will be treated with 1mg iv atropine. The spinal anesthesia will be considered as
      unsuccessful if the sensorial block level has not reached the T6 level before surgery or felt
      pain during skin incision. In this case, 10 ml of 15 ml 2% lidocaine + 2 ml bicarbonate + 2
      ml fentanyl + 1ml 1/200000 adrenaline solution will be given via epidural catheter and the
      patient will be excluded from the study. However, if pain felt again, will switch to general
      anesthesia. Post-spinal hypotension will be recorded from the onset of spinal anesthesia to
      the birth of the fetus. After the completion of the C-section, the time until the skin
      incision, uterine incision and time of birth, and the height, weight, BMI, and trimester of
      patients will be recorded. After the birth of the fetus, the study will be terminated and the
      total dose of ephedrine, adrenaline, and atropine used, as well as the amount of crystalloid,
      and colloid administered, and blood loss will be recorded. The study was triple-blind because
      the researchers who detected, recorded, and treated post-spinal hypotension did not know the
      results obtained from urological measurements and did not know about the groups analyzed by
      the statistician.

      STATISTICAL ANALYSIS

      Power analysis : Patients diagnosed with OAB are 15% more likely to develop hypotension than
      patients who do not receive this diagnosis. In order for a difference of 15% to be
      statistically significant, it was calculated by the PAS statistics program, which requires a
      total of 142 patients to be included in the study, where 71 patients should be in each group
      at a 95% confidence level at 80% power.

      The analyzes were done with IBM SPSS 20 statistical analysis program.

      Data were presented as mean, standard deviation, median, minimum, maximum, percentage, and
      number. The normal distribution of continuous variables was evaluated with the Shapiro Wilk-W
      test when the sample size was <50 and the Kolmogorov-Smirnov test when it was> 50.

      In the comparisons between two independent groups, the Independent Samples t test was used
      when the normal distribution condition was met and the Mann Whitney u test was used when it
      was not provided.

      In 2x2 comparisons between categorical variables, the expected value (> 5) was made using the
      Pearson Chi-square test, the expected value (3-5) was made using the chi-square yacht test
      and the expected value (<3) using Fisher's Exact test.

      The statistical significance level was taken as p <0.05.
    

Intervention name(s): bupivacaine,fentanyl
Intervention type(s): Other
Intervention description(s): According to our institution protocol, intravenous (iv) hydration will not be given as preload and afterload and vasopressor infusion will not be initiated before spinal anesthesia. After the skin is prepared sterile and local infiltration with 2% lidocaine is done, from L3-L4 OR L4-L5 range on midline with the 16 gauge Tuohy needle and the loss of resistance technique epidural space is identified and then 26 gauge pencil point needle is passed trough the Touhy and the dura will be drilled. After the cerebrospinal fluid (CSF) is seen the fluid containing 5mg isobaric bupivacaine and 15µg fentanyl will be given in 30 seconds to patients. After the spinal needle is removed, the epidural catheter is placed 3-5 cm in the epidural space through Tuohy, and after the catheter is fixated, the patients will be placed in the supine position by placing a height under their right hip with a 15 ° angle.
Intervention MeSH terms: Fentanyl; Bupivacaine
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Screening
Keywords: cesarean section; spinal-epidural; overactive bladder; post-spinal hypotension