Height Versus Height and Weight Based Spinal Bupivacaine on Maternal Haemodynamics for Elective Cesarean in Short Stature Patients
Condition: Maternal Hypotension After Spinal Anesthesia
MeSH terms: Dwarfism; Hypotension
Study type: Interventional
Phase: Phase 4

Summary: 
      Doses of intrathecal bupivacaine based on patients either height or height and weight has
      shown to lower the risk of maternal hypotension with similar quality of anesthesia compared
      to conventional doses.

      In clinical practice there is a tendency of reducing the dose of bupivacaine as either low
      fixed dose or using the doses based on either height and weight or height (0.06mg/cm) alone
      in parturient with short stature. However, there is lack of evidence regarding the
      appropriate dose required in this group of patients. Therefore, our aim is to compare the
      height versus height and weight based intrathecal bupivacaine dose for elective caesarean on
      maternal haemodynamics in short stature patients.
    

Detailed description: 
      Spinal induced hypotension in women undergoing caesarean section (CS) is the most common
      unwanted effect. The dose of intrathecal local anesthetic is the main determining factor that
      balances between successful block and an incidence of maternal hypotension. Although lowering
      the doses of intrathecal bupivacaine provides better maternal hemodynamic stability it
      compromises the quality of anesthesia. Moreover, there is no consensus regarding the cut-off
      at which the dose can be defined as low. Doses based on patients either height or height and
      weight has shown to lower the risk of maternal hypotension with similar quality of anesthesia
      compared to conventional doses.

      In clinical practice there is a tendency of reducing the dose of bupivacaine as either low
      fixed dose or using the doses based on either height and weight or height (0.06mg/cm) alone
      in parturient with short stature. However, there is lack of evidence regarding the
      appropriate dose required in this group of patients.

      Our aim is to compare the height versus height and weight based intrathecal bupivacaine dose
      for elective caesarean on maternal haemodynamics in short stature patients.

      Doses of intrathecal bupivacaine for elective caesarean section based on Harten chart is
      available from the following reference- Harten JM, Boyne I, Hannah P, Varveris D, Brown A.
      Effects of a height and weight adjusted dose of local anaesthetic for spinal anaesthesia for
      elective Caesarean section. Anaesthesia 2005; 60: 348-53.

      Consent for the participation in the study will be obtained during pre-anaesthetic assessment
      visits in the evening before surgery. The investigator will also educate the patients
      regarding the use of numeric rating scale scores. Preoperative anxiety will be recorded in
      numerical rating scale scores where 0 is no anxiety and 10 is maximum anxiety patient
      reported. The enrolled subjects will be randomly assigned to 2 equal groups (allocation
      ratio, 1:1) according to the codes generated from the website (www.sealedenvleop.com) using
      the variable block size of 4, 6 and 8. The group allocation will be concealed in sequentially
      numbered, sealed opaque envelopes that will be opened by the anaesthesia assistant not
      involved in the study only after the patient arrives in the operating room. The patient will
      be fasted for at least eight hours and will receive antibiotics, ranitidine 50 mg and
      metoclopramide 10 mg intravenously via 18-gauge cannula before transfer to the operation
      room. In the operating table patient will be laid supine with a wedge under right buttock and
      standard monitors (electrocardiography, pulse oximetry, and noninvasive BP) will be applied.
      Thereafter, successive three readings of heart rate (HR) and systolic blood pressure (SBP)
      will be taken at 2 minutes interval with difference not exceeding 10%. The average of these
      recordings will be documented by the investigators as baseline parameters. To maintain
      blinding, the investigator will leave the operating room and will return immediately once the
      spinal injection is initiated. Subarachnoid block will be performed by the attending
      anesthesiologist not involved in the study in the sitting position at the L3-L4 or L4-L5
      vertebral interspace using a 25-gauge spinal needle via midline approach. The study solution
      will be administered according to the group allocated. In Group A the dose of heavy
      bupivacaine will be based on height and weight and in group B the dose will be based on
      patient's height (0.06 mg/cm). 10 microgram fentanyl will be added to bupivacaine in both
      groups.
    

Intervention name(s): Hyperbaric bupivacaine spinal; Hyperbaric bupivacaine spinal
Intervention type(s): Drug; Drug
Intervention description(s): In this group patient will receive intrathecal hyperbaric bupivacaine based on patients height and weight according to Harten chart with 10 μg of fentanyl (0.1 ml); In this group will receive intrathecal hyperbaric bupivacaine based on patients height (0.06mg/cm) with 10 μg of fentanyl (0.1 ml)
Intervention MeSH terms: Bupivacaine
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Triple (Participant, Investigator, Outcomes Assessor)
Primary purpose: Treatment