Combined Spinal Epidural Anesthesia in Obese Patients Undergoing Cesarean Surgery
Condition: Obesity; Pregnancy Related; Cesarean Section Complications; Spinal Anaesthetic Poisoning of Undetermined Intent; Hypotension
MeSH terms: Hypotension; Poisoning
Study type: Interventional

Summary: 
      This study investigated the maternal and fetal effects during performance of CSEA in the left
      lateral decubitus and sitting positions in obese pregnant women undergoing elective cesarean
      section.
    

Detailed description: 
      The study population comprised 100 pregnant women diagnosed with obese aged between 18-45
      years, American society of anesthesiologist I and II with full-term gestation undergoing
      elective cesarean section under combined spinal - epidural anesthesia (CSEA). Women with
      psychiatric diseases, preeclampsia, pregnancy-induced hypertension or chronic hypertension,
      diabetes, multiple pregnancies, fetal anomaly and allergy to study drugs were excluded from
      the study. Also, patients requiring general anesthesia and patients with an average blood
      pressure below 90 and heart rate less than 50 were excluded. Before performance of CSEA, two
      groups were formed by randomization. A computer-generated table of random numbers was used
      for randomization. The CESA was performed in left lateral position in Group I (n=50) and in
      sitting position in Group II (n=50).

      Premedication was not performed in any patient. Before entering the operating room, 10 mL/kg
      lactated Ringer's solution was given to all patients via IV cannula over 20 minutes. Standard
      monitoring was performed in the operating room. Before the operation; patients' age, weight,
      height, ASA physical status and basal hemodynamic parameters were recorded. The CSEA was
      planned for all patients. All interventions were performed by an experienced
      anesthesiologist. Patients were appropriately positioned in accordance with the group in
      which they were included. Group I (n=50) consisted of patients performing CSEA in the left
      lateral decubitus position. The patient was laid on her left side, the legs were flexed on
      the abdomen and the chin on the chest. Group II (n=50) consisted of patients performing CSEA
      in the sitting position. The patient was seated on the edge of the operating table with his
      feet hanging down, the feet supported by a chair, a pillow was given on her lap, and the
      patient clung to the pillow. After the skin was sterilized and local infiltration was
      performed with 2% lidocaine, 18 gauge Tuohy needle (Set for CSEA, Braun®, Melsungen, Germany)
      was advanced through the midline L2-3 or L3-4 intervertebral spaces with loss of resistance
      technique. Intrathecally, a 27-gauge pencil point needle was inserted using the
      needle-through-needle technique. When free cerebrospinal fluid flow was seen, 1.8 ml 0.5%
      isobaric bupivacaine (9 mg) was administered over 30 seconds. The epidural catheter was
      advanced 3 cm into the epidural space following the spinal needle was removed. After the
      catheter was checked with negative pressure, it was secured in place. At the end of the
      procedure patients were placed in the supine position for operation and the operating table
      was tilted 20° to the left. Sensory block level was evaluated via pinprick test and it was
      recorded bilaterally every two minutes. Surgery was initiated following the sensory block
      reached at the upper level of T6 dermatome. If signs of analgesia were not observed within
      the first 20 min following the spinal injection, spinal anesthesia was evaluated as failed.
      In case of failure, additional 5 ml solution of 2% lidocaine was performed via the epidural
      catheter (5-min intervals, the total dose of 15 mg) until a T6 level of the sensory block was
      provided. Motor block level was evaluated with Modified Bromage scale (scale 0 = motor block
      is not available; scale 1 = The patient can do the full flexion of foot and knee, she is
      unable to hip flexion; scale 2 = The patient can do the full flexion of foot, she is unable
      to knee and hip flexion; scale 3 = Total motor block is available). General anaesthesia
      protocol was applied in case of three unsuccessful attempts to reach to intrathecal space.
      Oxygen was delivered during surgery. Intravenous ephedrine (6 mg) was used to treat
      hypotension (a 30% decrease in systolic blood pressure compared to preoperative values)
      during surgery. Intra-venous atropine (1 mg) was given in case of bradycardia (the heart rate
      < 45 beats/minute) during surgery. When nausea and vomiting were observed, intravenous
      metoclopramide (10 mg) was administered. The application time of the CSEA, the time from the
      spinal injection to the development of sensory blockade up to T6 dermatome, operation time
      (the time from the start of the surgical incision until the end of surgery), highest sensory
      block level, anesthetic complications and the number of patients required epidural medication
      during surgery were recorded. Following drug administration to the intrathecal space,
      intraoperative hemodynamic changes were recorded every 2 min. After surgery was initiated,
      hemodynamic changes were recorded in 5-minute intervals until the end of the operation. Side
      effects such as pruritus and nausea, the number of patients requiring ephedrine, atropine or
      analgesic were recorded. After delivery, 30 IU oxytocin in 500 mL Ringer's lactate solution
      was given intravenously. Neonatal Apgar scores obtained at 1 and 5 min after delivery and
      umbilical artery blood gas values were recorded.

      After surgery, patients were followed in the recovery room for 120 min. In the recovery room,
      Visual analogue scale (VAS, 0 cm= no pain, 10 cm= worst pain) scores for pain severity,
      anesthesia-related side effects (e.g., nausea, vomiting and headache), sensory block time
      (from the spinal injection to the recovery of T10 dermatome), and the time requiring
      supplemental analgesics was recorded by an independent observer blinded to the group
      assignment at 30 min and 1st and 2nd hours post-operatively. In the case of VAS > 3 in a
      patient, 5 ml solution of 2% lidocaine was given through the epidural catheter. When the
      motor block had regressed to the T10 level, patients were sent to the clinics.Sample size was
      calculated as minimum 40 patients in each group, based on data obtained in previous studies,
      to detect a minimum difference in the requirement of 10 mg ephedrine between the two groups
      with a power of 90%, a of 0.05. Accordingly, 50 pregnant women were recruited in each group
      to compensate for potential dropouts.

      Data were expressed as mean values ± standard deviation (SD) or number and percentage values.
      Whether the data has normal distribution was tested using Kolmogorov-Smirnov test.
      Comparisons were performed using the Mann-Whitney U-test, when data was not normally
      distributed. Comparisons were performed using the Independent T test in the presence of
      normally distributed data. The percentage values were compared using chi-square, P<0.05 was
      considered significant statistically.
    

Intervention name(s): left lateral decubitus position; sitting position; The use of intravenous ephedrine.; The use of intravenous atropine.; The use of intravenous metoclopramide
Intervention type(s): Other; Other; Drug; Drug; Drug
Intervention description(s): Comparator group consisted of patients performing CSEA in the left lateral decubitus position.; Active control group consisted of patients performing CSEA in the sitting position.; Intravenous ephedrine (6 mg) was used to treat hypotension (a 30% decrease in systolic blood pressure compared to preoperative values) during surgery.; Intravenous atropine (1 mg) was given in case of bradycardia (the heart rate < 45 beats/minute) during surgery.; When nausea and vomiting were observed, intravenous metoclopramide (10 mg) was administered.
Intervention MeSH terms: Atropine; Ephedrine; Metoclopramide
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: Comparator group consisted of patients performing CSEA in the left lateral decubitus position. Active control group consisted of patients performing CSEA in the sitting position.
Masking: Single (Outcomes Assessor)
Primary purpose: Prevention
Keywords: Combined spinal epidural anesthesia; obesity; cesarean section; lateral decubitus position; sitting position; hypotension