Methods
loss of sensation, premature rupture of amniotic membranes, cardiac disease, diabetes
HYPERTENSIVE DISORDER, COLD, CARDIAC DISEASE, DIABETES
This randomized controlled study was conducted from January 2020 to September 2021 at KK Women’s and Children’s Hospital, Singapore, after approval by the SingHealth Centralized Institutional Review Board (Ref: 2018/2213) on 06/04/2018 and registration on clinicaltrials.gov (NCT03620942) on 08/08/2018. Written informed consent was obtained from all participants in accordance with the Declaration of Helsinki, and this manuscript adhered to the relevant Consolidated Standards of Reporting Trials (CONSORT) guidelines.We included parturients aged 21 to 45 years old, weighing 40 to 100 kg, 145 to 170 cm in height, American Society of Anesthesiologists (ASA) physical status 2, with singleton full term pregnancies undergoing spinal anesthesia for elective cesarean delivery. Parturients with contraindication to spinal anesthesia, hypertensive disorders requiring medication, premature rupture of amniotic membranes for > 48 h, diabetes requiring insulin, and uncontrolled medical conditions such as cardiac disease were excluded.Parturients were randomized (1:1 ratio) to receive ADIVA or DIVA using a computer-generated random number generator. The allocation sequence was created by the study statistician and concealed using sequentially numbered opaque sealed envelopes. Prior to spinal anesthesia, the study investigator opened the envelope containing the group allocation. Parturients, obstetricians, nurses, and anesthesiologists involved in anesthesia management and data collection were blinded to the group allocation.Baseline SBP was measured in the ward as the mean of three consecutive readings taken at one-minute intervals using an oscillometric device on the right arm with the patient supine and left uterine displacement. Intravenous access was obtained using an 18-gauge cannula, pulse oximeter and electrocardiogram were applied, and the Nexfin finger cuff was attached to the right second or middle finger. Spinal anesthesia was performed in the sitting flexed position with a 27-gauge Whitacre needle (BD Medical, New Jersey, USA), 11 mg hyperbaric bupivacaine 0.5%, 15 μg fentanyl, and 100 μg morphine. The parturient was then positioned supine with left uterine displacement, free flowing infusion of lactated ringers solution was commenced, and the ADIVA system was initiated by the study investigator.SBP and heart rate measurements by Nexfin were uploaded continuously to a laptop computer which integrated the data every 10 s to form a moving average value (LabVIEW running on Windows XP, Microsoft Corporation, Washington, USA). The drug delivery system consisted of two syringe driver pumps (B.Braun, Melsungen, Germany) with one 50 ml syringe filled with 100 μg.mlSchematic diagram of the algorithm used in (Five minutes after spinal anesthesia, sensory block was assessed using loss of sensation to cold while motor block was measured using the modified Bromage scale [