A novel epidural delivery regimen was developed: Variable volume automated mandatory bolus (AMB) (VVAMB) will advance individualisation of labour epidural analgesia, by which a larger volume of bolus may contribute to better spread of the local anaesthetics within brief period and thereby reduces the chances of motor blockade that could reduce instrumental deliveries.
Healthy (American Society of Anesthesiologists (ASA) physical status 1 and 2) primiparous parturient at term (≥36 weeks gestation);
Singleton fetus;
In early labor stage (cervical dilation ≤5cm);
Request labor epidural analgesia and able to administer combined spinal epidural analgesia (CSEA) according to protocol.
Non-cephalic fetal presentation;
Obstetric (e.g. pre-eclampsia, premature rupture of amniotic membranes for more than 48 hours, gestational diabetes on insulin, pregnancy-induced hypertension on medication) and uncontrolled medical (e.g. cardiac disease) complications;
Have contraindications to neuraxial blockade or have received parenteral opioids within last 2 hours;
Dural puncture/ suspected dural puncture at initiation of CSEA.