Ultrasonographic Assessment of Gastric Residual Volume
Condition: Critically Ill; Enteral Feeding Intolerance
MeSH terms: Critical Illness
Study type: Observational [Patient Registry]

Summary: 
      A recent systematic review reported that the prevalence of enteral nutrition intolerance in
      critically ill patients ranged from 2% to 75%, and the pooled rate was 38.3%.Many randomized
      controlled trials have reported that the incidence of pneumonia, regurgitation and aspiration
      do not correlate well with gastric residual volume (GRV) monitoring. In addition, it was
      reported that GRV monitoring may cause more frequent obstructions in the enteral tube access,
      leading to greater loss of time for intensive care unit nurses and patients receiving less
      than the prescribed daily intake due to enteral nutrition interruptions. The most recent
      SCCM/ASPEN guidelines in 2016 recommended that GRV monitoring not be included in the daily
      care protocol, but many institutions still use it to determine whether to continue enteral
      nutrition or to detect enteral tube-feeding intolerance. This study aimed to evaluate the
      relationship between ultrasonographic gastric antral measurements and aspirated gastric
      residual volume GRV in mechanically ventilated critically ill patients receiving enteral tube
      feeding via nasogastric, orogastric, or percutaneous gastrostomy tubes.
    

Detailed description: 
      Data collection and measurements:

      The following clinical parameters of included patients will be recorded: age, sex, body
      weight, height, body mass index, Acute Physiology and Chronic Health Evaluation II (APACHE
      II) score on the day of admission,the Charlson Comorbidity Index score, any comorbid
      diseases, the total amount of EN product during the last 24 hours before ultrasonographic
      assessment, vasopressor therapy during imaging, and the dose of the vasopressors.

      Ultrasonographic gastric antrum imaging procedure:

      Ultrasonographic gastric antrum imaging will be carried out by the same intensivist on each
      patient just before routine tube-feed aspiration. Gastric antrum images will be obtained with
      a 2.5-6 MHz curvilinear probe placed in the sagittal plane of the epigastric region. All
      imaging attempts will be carried out in a 30-degree head-elevation supine position as
      described previously. Reference points will be used to obtain images of the gastric
      antrum-left anterior lobe of the liver, head of pancreas and abdominal aorta.The
      anteroposterior and craniocaudal diameters of the gastric antrum will be measured three times
      for each ultrasonographic assessment. The mean value of the three will be recorded. The
      universally accepted Two-Diameter Method defined by Bolondi et al. will be used for the
      measurement of antral cross-sectional area.

      Tube-feeding aspiration (GRV measurement) procedure:

      Routine gastric residual volume aspirations will be performed by the nursing staff blinded to
      the ultrasonographic measurements. The time between gastric antrum imaging and the beginning
      of GRV aspiration will be recorded in minutes. Gastric contents will slowly aspirated with 50
      ml syringes for at least 10 minutes until stomach contents could no longer be aspirated.
      Patients will be reassessed with ultrasonography after the aspiration to ensure that the
      stomach is completely emptied with aspiration.
    

Observational model: Cohort
Time perspective: Prospective
Sampling method: Probability Sample
Study population: 
        Mechanically ventilated critically ill patients receiving enteral feeding via nasogastric,
        orogastric, or percutaneous gastrostomy tubes who admitted to ICU in a one year period
      
Keywords: critical care; ultrasonography; enteral feeding; enteral nutrition; feeding intolerance; gastric volume