Maternal Microcirculation & SDF Imaging

Study Overview
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Brief Summary
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This is a study of pregnant women undergoing a cesarean delivery. It will compare their microcirculation before and after the anesthetic. Microcirculation means blood flow to the extremely small blood vessels in the body. It will also look at the differences in microcirculation of participants who receive an infusion of phenylephrine compared to participants who don't. The investigators hypothesize that spinal anesthesia will reduce the vascular density and proportion of perfused vessels.

Official Title
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Maternal Microcirculation & SDF Imaging: A Novel Assessment of the Microcirculation During Cesarean Delivery With Spinal Anesthesia and the Impact of Phenylephrine Prophylaxis to Prevent Spinal Anesthesia-induced Hypotension.

Conditions
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Pregnancy

Intervention / Treatment
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* Device: Initial MicroScan® (Microvision Medical) SDF Measurement
* Drug: Spinal Anesthesia- Bupivacaine
* Device: Comparative MicroScan® (Microvision Medical) SDF Measurement
* Drug: Bolus Phenylephrine/Ephedrine Treatment
* Drug: Phenylephrine Infusion


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: American Society of Anesthesiologists (ASA) Physical Status I-II (ASA I - Healthy, ASA II - mild and controlled systemic disease) Singleton pregnancies 36-42 weeks gestation Non-labouring Scheduled cesarean delivery English speaking Age 18-45 years Exclusion Criteria: Cardiovascular disease Hypertensive disease of pregnancy (i.e. mild & severe preeclampsia) Allergy to phenylephrine, or any other standardized medication Obesity (BMI > 35 kg/m2) Diabetes Mellitus type 1 Smoker Coffee/Caffeine intake within 6 hours of SDF measurement

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 45 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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No

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: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Bolus Phenylephrine/Ephedrine Treatment'<br>Initial MicroScan® (Microvision Medical) SDF measurement are recorded in the obstetric preoperative area within two hours prior to administration of spinal anesthesia. In the operating room participants will receive a standard spinal anesthetic (hyperbaric bupivacaine, fentanyl and preservative free morphine) followed by a second comparative MicroScan® (Microvision Medical) SDF measurement within 10 minutes of initiation of spinal anesthetic. Participants who experience hypotension will receive bolus phenylephrine and/or ephedrine treatment as needed. | Device: Initial MicroScan® (Microvision Medical) SDF Measurement<br>* Initial SDF measurements are recorded in the obstetric preoperative area within two hours prior to administration of spinal anesthesia.<br>Drug: Spinal Anesthesia- Bupivacaine<br>* The spinal anesthetic technique is standardized. In the operating room spinal anesthesia will be administered with the L2-L5 interspaces in the sitting position using 12 mg of hyperbaric bupivacaine with 15 mcg of fentanyl and 150 mcg of preservative free morphine.<br>Device: Comparative MicroScan® (Microvision Medical) SDF Measurement<br>* A second comparative SDF measurement be recorded within 10 minutes after induction of spinal anesthesia.<br>Drug: Bolus Phenylephrine/Ephedrine Treatment<br>* Participants who experience hypotension following induction of spinal anesthesia will be treated with a bolus of phenylephrine and/or ephedrine as needed.<br>|
| Experimental: Phenylephrine Infusion Group<br>Initial MicroScan® (Microvision Medical) SDF measurement are recorded in the obstetric preoperative area within two hours prior to administration of spinal anesthesia. In the operating room participants will receive a standard spinal anesthetic (hyperbaric bupivacaine, fentanyl and preservative free morphine) followed by a second comparative MicroScan® (Microvision Medical) SDF measurement within 10 minutes of initiation of spinal anesthetic. Participants will have an infusion of phenylephrine started immediately following the induction of spinal anesthesia for prevention of hypotension. | Device: Initial MicroScan® (Microvision Medical) SDF Measurement<br>* Initial SDF measurements are recorded in the obstetric preoperative area within two hours prior to administration of spinal anesthesia.<br>Drug: Spinal Anesthesia- Bupivacaine<br>* The spinal anesthetic technique is standardized. In the operating room spinal anesthesia will be administered with the L2-L5 interspaces in the sitting position using 12 mg of hyperbaric bupivacaine with 15 mcg of fentanyl and 150 mcg of preservative free morphine.<br>Device: Comparative MicroScan® (Microvision Medical) SDF Measurement<br>* A second comparative SDF measurement be recorded within 10 minutes after induction of spinal anesthesia.<br>Drug: Phenylephrine Infusion<br>* Participants will have an infusion of phenylephrine started immediately following the induction of spinal anesthesia for prevention of hypotension.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Microvascular Flow Index (MFI) | The change in MFI of participants; measured immediately prior to, and within 10 minutes following the induction of spinal anesthesia | Immediately prior to, and within 10 minutes of induction of spinal anesthesia | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Microvascular Flow Index (MFI) | The difference between the MFI measured within 10 minutes following the induction of spinal anesthesia in participants who receive phenylephrine via a continuous infusion for the prevention of spinal anesthesia-induced hypotension compared to those who may receive phenylephrine boluses for treatment of spinal anesthesia-induced hypotension. | Immediately prior to, and within 10 minutes of induction of spinal anesthesia | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Microcirculation, Sidestream Dark Field (SDF) Imaging, Spinal Anesthesia, Phenylephrine