POCUS Analysis of the Gastric Emptying Time of Orange Juice With and Without Pulp
Condition: Preoperative Period; Anesthesia
Study type: Interventional

Summary: 
      Preoperative fasting guidelines for anesthesia recommend waiting two hours after ingesting a
      clear liquid and six hours after ingesting a light meal. Due to the presence of pulp, orange
      juice is considered a light meal by current guidelines which means a patient must wait six
      hours before undergoing general anesthesia. This study will use ultrasound of stomach of
      healthy volunteers to determine if the presence of pulp actually increases the transit time
      for orange juice.
    

Detailed description: 
      Healthy volunteers will be solicited (medical students and attending anesthesiologists) to
      participate in the study. Volunteers will participate in two sessions, one for orange juice
      without pulp and one for orange juice with pulp. Participants will be NPO after midnight and
      will be asked to arrive at approximately 8 am. Upon arrival for females of child bearing age,
      a urine pregnancy test will be performed and they will be discreetly informed of the results
      of the test. After, all patients will have their gastric volume assessed using point-of-care
      ultrasound to ensure the study team is able to adequately identify their stomach as well as
      to ensure the stomach is empty. After measurements are made, participants will drink 12 oz
      (approximately 350 mL) of either orange juice with or without pulp. Two hours after finishing
      the juice they will again undergo point-of-care gastric ultrasound scanning. Images will be
      saved and will be examined by a blinded independent anesthesiologist. The study will entail
      two visits each lasting for approximately 3 hours.

      Point-of-care gastric ultrasound will be performed using a low-frequency curvilinear
      ultrasound probe. The exam will be performed on a stretcher with the participant in both the
      supine and right lateral decubitus (RLD) position. The goal of point-of-care gastric
      ultrasound is to obtain an image of the gastric antrum. The low-frequency large curvilinear
      probe is placed in the epigastric area in a sagittal or parasagittal plane immediately
      inferior to the patient's xiphisternum with the orientation marker directed cephalad. Image
      optimization requires scanning in an anterior and cephalad direction toward the liver by
      tilting the tail of the probe toward the feet. A qualitative analysis will occur first to
      rule out solid contents in the stomach. Once confirmed, the gastric antral cross-sectional
      area (CSA) will be measured in the RLD position. Correlation has been shown between CSA and
      total gastric fluid volume. A gastric volume less than 1.5 mL/kg is considered consistent
      with fasting.

      The study will be repeated for both orange juice with and without pulp.
    

Intervention name(s): Point of care gastric ultrasound
Intervention type(s): Other
Intervention description(s): Point-of-care gastric ultrasound will be performed using a low-frequency curvilinear ultrasound probe to assess stomach contents (empty vs. not empty, liquid vs. solid, gastric volume).
Allocation: Non-Randomized
Intervention model: Crossover Assignment
Masking: Single (Outcomes Assessor)
Primary purpose: Diagnostic