Closed-loop Double-vasopressor Automated System to Treat Hypotension During Spinal Anaesthesia for Caesarean Section
Condition: Hypotension
MeSH terms: Hypotension
Study type: Interventional
Phase: Phase 2/Phase 3

Summary: 
      Hypotension occurs commonly during spinal anesthesia for caesarean section with maternal and
      fetal adverse effects. The investigators developed a double-vasopressor automated system
      incorporating continuous non-invasive arterial pressure monitoring (CNAP, CNSystems,
      Austria).
    

Detailed description: 
      Hypotension occurs commonly during spinal anesthesia for cesarean section with maternal and
      fetal adverse effects. The investigators developed a double-vasopressor automated system
      incorporating continuous non-invasive arterial pressure (CNAP, CNSystems, Austria) monitoring
      feeding hemodynamic data to a laptop computer, which triggers syringe pumps to deliver
      phenylephrine 50mcg or ephedrine 4mg (if heart rate<60 beats.min-1) every 30 seconds when
      systolic blood pressure fell to below 90% of baseline.

      A randomised controlled trial was done to compare with manual bolus technique. With the
      manual bolus technique, phenylephrine 100mcg or ephedrine 8mg (if heart rate<60 beats.min-1)
      was given every 60 seconds by the attending anesthesiologist when systolic blood pressure was
      below 90% of baseline as measured by conventional intermittent non-invasive blood pressure
      monitoring.
    

Intervention name(s): Vasopressor automated delivery system; Phenylephrine; Ephedrine; Manual vasopressor delivery system
Intervention type(s): Device; Drug; Drug; Device
Intervention description(s): Novel closed-loop system incorporating:
Continuous non-invasive arterial pressure (CNAP) monitor that measured and recorded hemodynamic data in real time.
Controller algorithm loaded onto a laptop computer that monitored the hemodynamic data from CNAP and determined if vasopressors should be administered.
Two syringe pumps loaded with phenylephrine and ephedrine that was activated by the controller algorithm.; Phenylephrine is a vasopressor drug that was administered when the participant's systolic blood pressure fell below 90% of baseline systolic blood pressure, with heart rate of at least 60bpm.; Ephedrine is a vasopressor drug that was administered when the participant's systolic blood pressure fell below 90% of baseline systolic blood pressure, with heart rate of less than 60bpm.; Manual dosing system consisting:
Non-invasive intermittent blood pressure monitor that measured and recorded blood pressure at 1-minute intervals.
Attending anesthesiologist that noted the blood pressure readings and manually administered phenylephrine or ephedrine according to the algorithm.
Other intervention name(s): CNAP
Intervention MeSH terms: Phenylephrine; Oxymetazoline; Ephedrine; Vasoconstrictor Agents
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Triple (Participant, Care Provider, Investigator)
Primary purpose: Treatment
Keywords: hypotension; spinal anesthesia; cesarean section; phenylephrine; ephedrine; closed-loop system; continuous non-invasive monitor