Is There a Relation Between Unilateral Epidural Block and Repeated Epidural Anesthesia?
Condition: Incidence; Unilateral; Epidural Block
Study type: Interventional
Phase: Phase 4

Summary: 
      epidural block is today the most common method of pain relief during labor. With increased
      use of epidural analgesia, many women are found in the second or third pregnancy and require
      repeated epidural analgesia. But there was a higher incidence of unilateral blockade among
      women receiving their repeated epidural which causes patient unsatisfaction.

      Objectives: Examination of the performance and outcome of women receiving their first versus
      repeated epidural block.

      Patients and methods: The study included 140 American Society of Anesthesiologists (ASA)
      Physical Status II patients (age range 20 to 40 years) and scheduled for normal vaginal
      delivery. The patients were divided randomly into two equal groups. Group (A) in which 70
      women primipara subjected to their first epidural block while group (B) in which 70 women
      multipara subjected to their repeated epidural block. For each patient, the following data
      were collected: demographic data, details of labor (gestation, cervical dilatation), visual
      analogue scale (VAS) before the epidural and 30 minutes after injection of local anesthetic
      and incidence of unilateral block.
    

Detailed description: 
      This study was performed after obtaining approval from the ethical committee of the Ain Shams
      University. Sample of 140 healthy ASA II female patients, 20-40 years of age, scheduled for
      normal vaginal delivery. Patients were randomly allocated by computer-generated random number
      list into two study groups of 70 patients each.

      Group (A) in which 70 primipara women subjected to their first epidural block while group (B)
      in which 70 multipara women subjected to their repeated epidural block. The study was carried
      out between January 2018 and March 2018.

      Patients were excluded for:

        -  Any physical reason for difficult epidural performance e.g.: morbid obesity, or
           scoliosis,

        -  Severe hypertension,

        -  Congestive heart failure,

        -  Coagulopathy,

        -  Significant hepatic or renal disease,

        -  Or withdrawal of consent. All patients in this study were subjected to a detailed
           pre-anesthetic evaluation. All basic investigations according to the hospital protocol
           (e.g. serum hemoglobin, platelet count, coagulation profile) were checked.

      The patient's demographic data, details of labor (gestation, cervical dilatation), details of
      epidural insertion were recorded by the anesthetist performing the epidural.

      The patient was asked to mark a visual analogue scale (VAS) (figure 1) before the epidural
      and 30 minutes after injection of local anesthetic. Also incidence of unilateral epidural
      block is reported 30 minutes after injection of local anesthetic.

      Figure (1): Visual analog scale 2.2 Anesthetic technique On arrival to operation room; 18 g
      cannula was inserted then 500 ml of Ringer solution was infused while performing the
      epidural.

      Basic monitors including automatic blood pressure measurements, five lead ECG monitor, and
      finger pulse oximetry were applied to all patients.

      A standard procedure was followed for epidural insertion and establishment of block. With the
      patient in the sitting position the midline approach was used using 16-g Tuohy needle and the
      epidural space was identified by loss of resistance to air, as is our routine practice.

      Once the epidural space was reached, Bupivacaine 0.25% plain, was given in three 5 ml
      increments at five-minute intervals, the first administered through the needle while the
      patient is in sitting position, and then through the catheter with the patient in supine
      position.

      Multi-orifice catheters were inserted and fixed to a standard 4 cm extra to the distance
      between the skin and epidural space. At the time of insertion of the catheter the patient was
      asked to report any pain or tingling experienced.

      The operator recorded the ease of insertion of the catheter (difficult or easy) and the
      occurrence of blood in needle or catheter. Epidurals were performed by the same anesthetists.

      At 30 min after injection of bupivacaine, the second VAS was completed and the level of
      blockade checked by cold sensation test. If an inadequate level was noted (less than T10),
      the pain score remained high or increased, or the patient complained of poor pain relief she
      was asked to describe the site and type of pain experienced.

      A unilateral block was defined as the description by the patient of worse pain on one side
      than the other, or pain on one side only, combined with either a 30-min pain score minimally
      changed or increased from time zero or a low level of blockade on the painful side, or both.
      If unilateral or inadequate block occurred the catheter was withdrawn 0.5-1 cm and a further
      5 ml bupivacaine 0.25% was administered with the patient lying on the unblocked side. If the
      block was still inadequate, epidural fentanyl 50 microgram was given and if still inadequate
      the catheter was removed and a second epidural catheter inserted in another interspace.

      The number of repeat injections of bupivacaine and length of time between epidural insertion
      and delivery were noted, as well details of previous epidurals in the multiparous women.

      Sample size estimation:

      To show a difference in the incidence of unilateral block between the two groups with p-value
      < 0.05 and power 80%, we needed at least 60 patients per group.

      Statistical analysis:

      Analysis of data was done by IBM computer using SPSS (statistical program for social science,
      version 16) as follows:

        -  Description of quantitative variables as mean ± SD.

        -  Description of quantitative variables as number and percentage. Statistical analysis was
           performed using statistical tests included Student's t-test, Chi square test and table
           analysis. P value <0.05 is considered significant.
    

Intervention name(s): marcaine
Intervention type(s): Drug
Intervention description(s): epidural block
Intervention MeSH terms: Bupivacaine
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: double blinded randomized
Masking: Double (Participant, Investigator)
Primary purpose: Diagnostic
Keywords: unilateral, ,; epidural block; repeated epidural