Effect of Height Versus Height and Weight Based Intrathecal Bupivacaine Dose on Maternal Haemodynamics for Elective Caesarean Section in Short Stature Patients: A Randomized Trial
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.
Condition:
Maternal Hypotension After Spinal Anesthesia
Treatment:
Hyperbaric bupivacaine spinal
Start Date:
November 30, 2019
Sponsor:
B.P. Koirala Institute of Health Sciences
For More Information:
https://clinicaltrials.gov/show/NCT04082676