Closed-loop Double-vasopressor Automated System to Treat Hypotension During Spinal Anaesthesia for Caesarean Section

Study Overview
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Brief Summary
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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
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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.

Official Title
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Closed-loop Double-vasopressor Automated System vs Manual Bolus Vasopressor to Treat Hypotension During Spinal Anaesthesia for Caesarean Section

Conditions
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Hypotension

Intervention / Treatment
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* Device: Vasopressor automated delivery system
* Drug: Phenylephrine
* Drug: Ephedrine
* Device: Manual vasopressor delivery system


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: age 21-45 years old, weight 40-90 kg, height 145-170 cm Exclusion Criteria: contraindications to spinal anaesthesia, allergy to drugs used in the study, and those with uncontrolled medical conditions such as hypertension, diabetes mellitus, and cardiovascular disease

Ages Eligible for Study
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Minimum Age: 21 Years
Maximum Age: 45 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: vasopressor delivery automated system<br>vasopressor delivery automated system that administered phenylephrine and ephedrine based on data from continuous non-invasive hemodynamic monitor | Device: Vasopressor automated delivery system<br>* 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.<br>* Other names: CNAP;Drug: Phenylephrine<br>* 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.<br>Drug: Ephedrine<br>* 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.<br>|
| Active Comparator: manual vasopressor delivery<br>manual bolus that delivered phenylephrine and ephedrine based on data from non-invasive intermitted blood pressure monitor | Drug: Phenylephrine<br>* 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.<br>Drug: Ephedrine<br>* 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.<br>Device: Manual vasopressor delivery system<br>* 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.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Hypotension | Incidence of systolic blood pressure less than 80% of baseline systolic blood pressure | 1 day | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Hypertension | Incidence of systolic blood pressure more than 120% of baseline systolic blood pressure | 1 day | 
| Nausea and vomiting | Incidence of nausea and vomiting during cesarean section | 1 day | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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hypotension, spinal anesthesia, cesarean section, phenylephrine, ephedrine, closed-loop system, continuous non-invasive monitor