Gastric emptying evaluation by ultrasound prior colonoscopy: an easy tool following bowel preparation

Abstract

Aim: To investigate the gastric emptying after bowel preparation to allow general anaesthesia.

Methods: A prospective, non-comparative, and non-randomized trial was performed and registered on Eudra CT database (2011-002953-80) and on www.trial.gov (NCT01398098). All patients had a validated indication for colonoscopy and a preparation using sodium phosphate (NaP) tablets. The day of the procedure, patients took 4 tablets with 250 mL of water every 15 min, three times. The gastric volume was estimated every 15 min from computed antral surfaces and weight according to the formula of Perlas et al (Anesthesiology, 2009). Colonoscopy was performed within the 6 h following the last intake.

Results: Thirty patients were prospectively included in the study from November 2011 to May 2012. The maximum volume of the antrum was 212 mL, achieved 15 min after the last intake. 24%, 67% and 92% of subjects had an antral volume below 20 mL at 60, 120 and 150 min, respectively. 81% of patients had a Boston score equal to 2 or 3 in each colonic segment. No adverse events leading to treatment discontinuation were reported.

Conclusion: Gastric volume evaluation appeared to be a simple and reliable method for the assessment of gastric emptying. Data allow considering the NaP tablets bowel preparation in the morning of the procedure and confirming that gastric emptying is achieved after two hours, allowing general anaesthesia.

Keywords: Colonoscopy; Gastric emptying; Preparation; Ultrasound.

Figures

Figure 1

Protocol schedule the day of the colonoscopy. NaP: Sodium phosphate bowel preparation.

Figure 2

Measurement of the surface antral by ultrasonography in a patient in right lateral position at baseline. A: Measurement after 12 h of gastric rest; B: Measurement after the ingestion of 750 mL water plus 12 tablets of NaP in 45 min showing a distortion of the antrum. NaP: Sodium phosphate bowel preparation.

Figure 3

Ultrasound method of assessing gastric emptying time based on measurements of gastric antrum. CSA: Cross sectional area.

Figure 4

Evaluation of gastric volume and residual volume using ultrasonography. A: Percent of patients with a residual antral volume above 20 mL at each time. Results are expressed in percent of the overall population (n = 27); B: Modification of the gastric volume. Results are expressed in mean ± SD of the overall population (n = 27).

Figure 5

Evolution of gastric volume. A: Evolution of gastric volume according to gender; B: Evolution of gastric volume according to body mass index; C: Evolution of gastric volume according to or smoking habits; D: Gastric emptying evolution considering the time when gastric volume returns to baseline (after 12 h fasting).