Gastric Voume Assessment for Aspiration Risk in OB ERAS Patients

Pre-Operative Gastric Volume Assessment Following Carbohydrate-Loading in Obstetrical Patients Undergoing Elective Cesarean Section: A Randomized Clinical Pilot Study

In recent years, human and animal studies have found that carbohydrate-loading prior to surgery leads to improved response to surgical stress and improved postoperative well-being when compared to traditional fasting guidelines. Such positive findings have lead to the increased use of preoperative intake of carbohydrate rich drinks prior to elective surgeries.

However, one of the biggest risks during surgery when a patient is asleep is having stomach contents come up into the lungs. For this reason, a stomach that is empty or has minimal amount of contents is safest. Historically, patients have been instructed not to eat or drink for 8 hours before surgery because it was thought to lower the risk of having fluid or contents in the stomach. This is the current practice patients are asked to follow before undergoing a C-section. However, non-pregnant patients undergoing other surgeries are instructed to have carbohydrate-rich drinks because of the potential benefits. Using ultrasound, the abdomen can be simply scanned to see if there are stomach contents present before surgery. This can allow for the potential determination of what the aspiration risk may be.

What the investigators want to do is look at the safety of using carbohydrate-loading in patients having a C-section. The investigators want to make sure that patients who follow carbohydrate-loading by having a clear, sugary drink 3 hours before a C-section are not at greater risk of having a large amount of stomach contents and be at higher risk of aspirating. This will be done by taking an ultrasound scan of the stomach that will tell the investigators if there are contents in the stomach and whether there is a risk of aspiration.

Patients having an elective C-section will be randomized into two groups. The first group will follow carbohydrate-loading by having a drink of apple juice or cranberry juice cocktail the night before (800mL) and 3 hours before (400mL) the C-section. The second group will follow standard practice of not eating or drinking less than 8 hours prior to surgery. An anesthesiologist will ultrasound the stomach 1 hour before the scheduled procedure time. The first ultrasound will be completed in the supine position (lying on back). The second will be done in the right lateral decubitus position (lying on right side). This should not take more than 5-10 minutes total.

Inclusion Criteria:

• Non-laboring pregnant women
• ≥36 weeks gestational age
• scheduled elective cesarean delivery
• ≥18 years of age
• ASA physical status I to III
• weight 50 to 120 kg
• height ≥150 cm
• Ability to understand the rationale of the study assessments

Exclusion Criteria:

• multiple gestation
• abnormal anatomy of the upper gastrointestinal tract
• gestational diabetes or pre-existing diabetes mellitus
• previous surgical procedures on the esophagus, stomach, or upper abdomen