title: Quantitative evaluation of gastric contents using ultrasound.
abstract: OBJECTIVE
  To describe a method of the authors' design for estimating gastric volume quantitatively using ultrasound and to evaluate the usefulness of this method in the clinical setting.
  
  
  METHODS
  Prospective, two-phase clinical study.
  
  
  METHODS
  University hospital. PATIENTS AND VOLUNTEERS: Phase 1 study: 31 patients who were undergoing general anesthesia and had no gastrointestinal disorder. Phase 2 study: 8 healthy volunteers.
  
  
  METHODS
  With each subject in the sitting position, a cross-sectional view of the stomach was obtained via ultrasound along the median line of the epigastric region. The cross-sectional area of the stomach (CSA) was measured by the analysis unit on the basis of the trace-enclosure method, and a mean value was obtained from triplicate measurements.
  
  
  RESULTS
  In the phase 1 study, CSA was measured after the patient had fasted for 1 hour, 4 hours, and more than 8 hours. CSA (cm2) was 19.2 +/- 0.9 cm2 at 1 hour, 11.0 +/- 0.7 cm2 at 4 hours, and 5.5 +/- 0.4 cm2 at more than 8 hours. That is, CSA significantly decreased as fasting time was prolonged (p < 0.001 for 1 hour vs. more than 8 hours and 4 hours vs. more than 8 hours). Most of the patients (87%) who fasted for more than 8 hours had a CSA less than 8.0 cm2. In the phase 2 study, after patients had fasted for more than 8 hours, CSA was measured both before and 5 minutes after the patient drank 50 ml of milk. CSA was 5.0 +/- 0.5 cm2 before and 8.5 +/- 0.9 cm2 after ingestion of the milk (p < 0.001). All subjects had a CSA less than 8.0 cm2 before drinking the milk, whereas only 2 of 8 patients had a CSA less than 8.0 cm2 after.
  
  
  CONCLUSIONS
  This method would be useful to estimate gastric contents quantitatively, and a CSA of 8.0 cm2 might be a valid indicator of an empty stomach.
authors.affiliation: Department of Anesthesiology, Nagasaki University School of Medicine, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Fujigaki
authors.forename: M
authors.initials: M
authors.lastname: Fukusaki
authors.forename: H
authors.initials: H
authors.lastname: Nakamura
authors.forename: O
authors.initials: O
authors.lastname: Shibata
authors.forename: K
authors.initials: K
authors.lastname: Sumikawa
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D005069:Evaluation Studies as Topic; D005215:Fasting / Q000502:physiology; D005260:Female; D005740:Gases; D005766:Gastrointestinal Contents / Q000187:drug effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D008892:Milk; D011446:Prospective Studies; D015203:Reproducibility of Results; D013270:Stomach / Q000000981:diagnostic imaging* / Q000187:drug effects / Q000502:physiology; D013997:Time Factors; D014463:Ultrasonography
chemical_list: D005740:Gases; D001285:Atropine