By GI Motility - distal (small and large intestine)Leave a Comment on Ultrasound (Peristaltis)

Ultrasound (US) can be used for assessment of several aspects of GI function: estimate dimensions and characteristics of different structures (diameter of different parts of GI tract, thickness of intestinal wall, presence and amount of free fluid), estimate presence and quality of motility and estimate perfusion.

Feasibility/Equipment: Ultrasound is a common bedside tool in the ICU. Competence is different between ICU providers.

Scoring information: Cut-offs are available for estimation of gastric emptying by measuring cross-sectional area (CSA) of the gastric antrum and for bowel dilatation/distension. A standardized protocol for GI ultrasound (GIUS) is not available.

Cost: Costs are low (providing that US-machine is available), but specific training is necessary.

Evidence: While the role of point-of-care ultrasound in cardiovascular and respiratory assessment is well established, GIUS is less so. Even though GIUS has been suggested for routine monitoring, no standardized protocol nor scoring is currently available [1]. Perez-Calatayud et al. proposed using GUTS protocol (gastrointestinal and urinary tract sonography) to assess GI dysfunction in critically ill [2], but this empirically developed protocol has not been validated.

Ultrasound could complete or replace several currently used clinical assessments included in the gastrointestinal dysfunction score (GIDS) [3]. A prospective observational study demonstrated that ultrasonographic measurement of antral cross-sectional can reliably estimate gastric residual volume (GRV) [4]. Studies have demonstrated that auscultation of bowel sounds is not accurate in differentiating between patients with normal and pathologic bowel sounds [5], whereas a sonographic assessment of dilated bowel loops and peristalsis had a sensitivity of 92% and specificity of 94% compared to a CT scan in the diagnosis of small bowel obstruction [6]. GIUS may assist in prediction of enteral feeding intolerance [7,8].

Ultrasound can be used to assess bowel wall thickening (occurring due to inflammation/edema) with reported high accuracy for patients with inflammatory bowel disease [9].

Presence of intraperitoneal free fluid can be reliably detected with ultrasound, whereas there is less data on trustworthy identification of the type of fluid [10].

Duplex ultrasound can be used to estimate blood flow in splanchnic arteries [11,12]. Assessment of the venous excess with US (VExUS) [13] is gaining attention in critical care, cardiology and nephrology. Color Doppler sonography additionally allows assessment of GI mural blood flow, but data are limited to patients with proven ischemic colitis [14].

Accuracy/Measurement properties

Ultrasound assessment is observer-dependent and GIUS is currently not included in training programs for intensivists. Assessment of presence of intraperitoneal free fluid is widely used as a part of FAST (Focused Assessment with Sonography for Trauma) with accuracy of 80% in an earlier study [15], improved to >90% with recently developed digital algorithms in trauma patients [16]. Small studies in selected patient populations have shown high accuracy of ultrasound in assessment of bowel dilatation, bowel wall thickness, blood flow etc, but studies on unselected ICU population assessing variety of aspects of GI (dys)function are lacking.

References:

  1. Reintam Blaser A, Preiser JC, Fruhwald S, et al. Gastrointestinal dysfunction in the critically ill: a systematic scoping review and research agenda proposed by the Section of Metabolism, Endocrinology and Nutrition of the European Society of Intensive Care Medicine. Crit Care. 2020 May 15;24(1):224..
  2. Perez-Calatayud AA, Carrillo-Esper R, Anica-Malagon ED, et al. Point-of-care gastrointestinal and urinary tract sonography in daily evaluation of gastrointestinal dysfunction in critically ill patients (GUTS Protocol). Anaesthesiol Intensive Ther. 2018;50(1):40-48.
  3. Reintam Blaser A, Padar M, Mändul M, et al. Development of the Gastrointestinal Dysfunction Score (GIDS) for critically ill patients – A prospective multicenter observational study (iSOFA study). Clin Nutr. 2021 Aug;40(8):4932-4940. 
  4. Taskin G, Inal V, Yamanel L. Does ultrasonographic assessment of gastric antrum correlate with gastric residual volume in critically ill patients? A prospective observational study. J Clin Monit Comput. 2021 Aug;35(4):923-929
  5. Felder S, Margel D, Murrell Z, Fleshner P. Usefulness of bowel sound auscultation: a prospective evaluation. J Surg Educ. 2014 Sep-Oct;71(5):768-73.
  6. Tamburrini S, Lugarà M, Iaselli F, et al. Diagnostic Accuracy of Ultrasound in the Diagnosis of Small Bowel Obstruction. Diagnostics (Basel). 2019 Aug 6;9(3):88.
  7. Gao T, Cheng MH, Xi FC, et al. Predictive value of transabdominal intestinal sonography in critically ill patients: a prospective observational study. Crit Care. 2019 Nov 27;23(1):378.
  8. Yu G, Jin S, Wang R, et al. Transabdominal gastro-intestinal ultrasonography (TGIU) for predicting feeding intolerance in critically ill patients: A prospective observational study. Clin Nutr ESPEN. 2023 Jun;55:76-82.
  9. Lim KY, Raja Ali RA, Wong Z, et al. Evaluation of intestinal ultrasound for disease activity assessment in patients with inflammatory bowel disease: A cross-sectional study at a tertiary centre in Malaysia. Saudi J Gastroenterol. 2023 Mar 3.
  10. Getnet W, Kebede T, Atinafu A, Sultan A. The Value of Ultrasound in Characterizing and Determining the Etiology of Ascites. Ethiop J Health Sci. 2019 May;29(3):383-390.
  11. Nylund K, Gjengstø AJ, von Volkmann HL, Gilja OH. Assessment of Small Bowel Motility and SMA Blood Flow Studied with Transabdominal Ultrasound. Ultrasound Int Open. 2022 Sep 23;8(1):E15-E21.
  12. AbuRahma AF, Stone PA, Srivastava M, et al. Mesenteric/celiac duplex ultrasound interpretation criteria revisited. J Vasc Surg. 2012 Feb;55(2):428-436.e6
  13. Beaubien-Souligny W, Rola P, Haycock K, et al. Quantifying systemic congestion with Point-Of-Care ultrasound: development of the venous excess ultrasound grading system. Ultrasound J. 2020 Apr 9;12(1):16.
  14. Danse EM, Van Beers BE, Jamart J, et al. Prognosis of ischemic colitis: comparison of color doppler sonography with early clinical and laboratory findings. AJR Am J Roentgenol. 2000 Oct;175(4):1151-4
  15. Kumar S, Bansal VK, et al. Accuracy of Focused Assessment with Sonography for Trauma (FAST) in Blunt Trauma Abdomen-A Prospective Study. Indian J Surg. 2015 Dec;77(Suppl 2):393-7.
  16. Leo MM, Potter IY, Zahiri M, et al. Using Deep Learning to Detect the Presence and Location of Hemoperitoneum on the Focused Assessment with Sonography in Trauma (FAST) Examination in Adults. J Digit Imaging. 2023 Jun 7.

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