Maternal Microcirculation & SDF Imaging

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.

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.

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