Gastric Volume Estimation by Ultrasonography After Glucose Loaded Clear Fluid Ingestion in Fasted Adult
Condition: Healthy Participants
Study type: Interventional

Summary: 
      Introduction; Pre operative gastric ultrasonography is a newly developed tool used to
      evaluate gastric content and volume in assessing perioperative aspiration risk and guide
      anaesthetic management. Gastric antrum is the most amenable and most consistently identified
      region for sonographic examination during assessment even in empty state. Baseline gastric
      secretions and clear fluids i.e: water, apple juice and tea have hypoechoeic or anechoic
      appearance, whilst milk, thick fluids, or suspensions will have increased echogenicity.
      Evaluation with sonographic assessment were found to be accurately reflective of gastric
      content in various studies.

      In this study, healthy volunteers were recruited. They will be required to fast at least 8
      hours prior to baseline gastric antrum ultrasonography assessment. Following that, they will
      require to drink 250ml glucose loaded drinks. Repeated Ultrasound assessment will be done
      after 1 hour of glucose loaded drink ingestion in Group 1 and after 2 hours in Group 2.
      Hypothesis of the study is there will be no significant different between ultrasound
      assessment between this 2 groups.
    

Detailed description: 
      This prospective randomized controlled trial study will be conducted in the Department of
      Anaesthesiology and Intensive Care UKM for eight months period from November 2018 to June
      2019 involving healthy adult volunteers comprising staff members of Department of
      Anaesthesiology and Intensive Care, after obtaining approval from Research Committee of the
      Department of Anaesthesiology & Intensive Care, Hospital Canselor Tuanku Muhriz, Universiti
      Kebangsaan Malaysia Medical Centre (UKMMC) and the Medical Research & Ethics Committee,
      UKMMC. Written informed consent will be obtained from volunteers who fulfill the inclusion
      criteria.

      All volunteers will be fasted, a minimum of 8 hours (duration of fasting will be recorded
      before the study begin) and will undergo baseline ultrasonographic gastric assessment (t0).

      All subjects in Group 1 and group 2 will drink 250 ml of lychee juice (glucose loaded clear
      fluid containing solution with lychee flavor; 145 kcal in 250 ml) after completion of
      baseline gastric assessment.

      Group 1 subjects will then continue fasting for one hour until completion of second
      sonographic antral assessment. Subjects in Group 2 will continue fasting for 2 hours until
      second sonographic antral assessment scan is completed.

      Subjects will be divided into 2 groups via computer randomization which will be allocated by
      anaesthesia trainee that will not be taking part in the analytical and further write up
      phases of the study. Ultrasonographic volume assessment will be conducted by a single
      operator who is an anaesthesia Masters trainee, experienced in diagnostic abdominal
      ultrasound with more than 20 sonographic gastric volume assessments. The images will be
      recorded and validated by a consultant radiologist.

      Ultrasonographic views of antral area will be obtained using a curvilinear array 2- to 5-MHz
      transducer and a Mindray DC-70 (Shanghai, China) with image compounding technologies. Images
      will be obtained with the stomach at rest, and between peristaltic contractions. Sonograms of
      the antral area will be examined in 2 views, cross-section in the supine position, followed
      by the right lateral decubitus position, at each of the two scanning sessions.

      During ultrasonography, the antrum will be imaged in a parasagittal plane in the epigastric
      area using the left lobe of the liver, the inferior vena cava, and the superior mesenteric
      vein as internal landmarks. The two vessels are usually visualized slightly to the right of
      the abdominal midline. Once these vessels were identified, the transducer will be rotated
      slightly clockwise or counterclockwise to best obtain a true cross-sectional view of the
      antrum. The anteroposterior and craniocaudal diameters will be measured in this view.

      CSA of the antral area (a two-dimensional section) will be calculated according to the
      formula previously used by Bolondi18 using two maximum perpendicular diameters.

      This formula essentially represents the surface area of an ellipse, as follows: CSA (AP x CC
      x pie/4), where AP is the anteroposterior diameter and CC is the craniocaudal diameter
      measures in one decimal point.

      Estimation of gastric volume will be obtain using this formula:

      Predicted gastric volume based on right lateral CSA value : 27 + 14.6 * right lat CSA -
      1.28*age (negative volume value indicates and empty state).
    

Intervention name(s): glucose loaded clear fluid
Intervention type(s): Other
Intervention description(s): Ultrasound assessment of gastric antrum is done at different time interval following glucose loaded clear fluid ingestion
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Screening
Keywords: gastric antrum ultrasonography; Gastric volume estimation; aspiration risk