Ultrasound assessment of gastrointestinal luminal contents: a narrative review

Gastro-intestinal ultrasound (GIUS) is a non-invasive and cost-effective tool, widely used as a first-line diagnostic method in patients presenting with abdominal complaints, especially in patients affected by inflammatory bowel disease (IBD), such as Crohn's disease and ulcerative colitis. In this setting, gastro-intestinal ultrasound has been especially used to evaluate the bowel wall features (thickening, stratification, vascularization) and complications related to IBD (fistulas, abscesses). Nevertheless, gastro-intestinal ultrasound can be also used to detect and evaluate the content of several segments of the gut. In fact, there is a growing interest in utilizing GIUS for suspected functional disorders, where assessing intestinal content may play a significant diagnostic role, as well as directing therapy. In our review, we provided a sonographic description of GIUS appearances of bowel content in various pathological and physiological conditions, offering potential applications in clinical practice and providing insights for further research.

In Vitro and In Vivo Test Methods for the Evaluation of Gastroretentive Dosage Forms

More than 50 years ago, the first concepts for gastroretentive drug delivery systems were developed. Despite extensive research in this field, there is no single formulation concept for which reliable gastroretention has been demonstrated under different prandial conditions. Thus, gastroretention remains the holy grail of oral drug delivery. One of the major reasons for the various setbacks in this field is the lack of predictive in vitro and in vivo test methods used during preclinical development. In most cases, human gastrointestinal physiology is not properly considered, which leads to the application of inappropriate in vitro and animal models. Moreover, conditions in the stomach are often not fully understood. Important aspects such as the kinetics of fluid volumes, gastric pH or mechanical stresses have to be considered in a realistic manner, otherwise, the gastroretentive potential as well as drug release of novel formulations cannot be assessed correctly in preclinical studies. This review, therefore, highlights the most important aspects of human gastrointestinal physiology and discusses their potential implications for the evaluation of gastroretentive drug delivery systems.

Accuracy of trans-abdominal ultrasound in a simulated massive acute overdose

INTRODUCTION

Toxic ingestions are a common cause of morbidity and mortality in the United States. In 2013, there were nearly 2 million reported ingestions and nearly 1000 deaths from poisonings. There is no well-validated imaging study for confirming the presence of pills in the stomach of an overdose patient. There are case reports of ultrasound used for confirmation of pills in the stomach, and we are aware of one prospective trial to evaluate sonography for this application.

OBJECTIVE

To determine the sensitivity and specificity of transabdominal ultrasound for visualization of ingested pills.

METHODS

Randomized, blinded, placebo-controlled study. Twenty Subjects were randomized to one of two groups. The experimental group ingested 50 enteric-coated placebo capsules with 1 liter of fluid. The control group ingested only 1 liter of fluid. At time 0, 60, and 90 minutes after ingestion, expert sonographers performed transabdominal ultrasound in an attempt to visualize pills in the stomach.

RESULTS

At time 0, 60, and 90 minutes post-ingestion, ultrasound had a sensitivity of 62.5% (41.1%, 81.9%), 20.8% (4.6%, 37.1%), and 25% (7.7%, 42.3%) respectively. The specificity at time 0, 60, and 90 minutes post-ingestion were 58.3% (21.9%, 61.4%), 79.1% (62.9%, 95.5%), and 70.8% (52.6%, 89.0%) respectively.

CONCLUSION

There is poor sensitivity and specificity for ultrasound detection of pills in the stomach at time 0; these values fell substantially at 60 and 90 minutes post-ingestion. In this pilot study, we did not find ultrasound to be a useful screening tool for detecting pills in the stomach.

Impact of decontamination therapy on ultrasound visualization of ingested pills

Introduction

Acute toxic ingestion is a common cause of morbidity and mortality. Emergency physicians (EP) caring for overdose (OD) patients are often required to make critical decisions with incomplete information. Point of care ultrasound (POCUS) may have a role in assisting EPs manage OD patients. We evaluated the impact of different liquid adjuncts used for gastric decontamination on examiners’ ability to identify the presence of tablets using POCUS, and assessed examiners’ ability to quantify the numbers of tablets in a simulated massive OD.

Methods

This prospective, blinded, pilot study was performed at an academic emergency department. Study participants were volunteer resident and staff EPs trained in POCUS. Five nontransparent, sealed bags were prepared with the following contents: 1 liter (L) of water, 1 L of water with 50 regular aspirin (ASA) tablets, 1 L of water with 50 enteric-coated aspirin tablets (ECA), 1 L of polyethylene glycol (PEG) with 50 ECA, and 1 L of activated charcoal (AC) with 50 ECA. After performing POCUS on each of the bags using a 10-5 MHz linear array transducer, participants completed a standardized questionnaire composed of the following questions: (1) Were pills present? YES/NO; (2) If tablets were identified, estimate the number (1–10, 11–25, >25). We used a single test on proportions using the binomial distribution to determine if the number of EPs who identified tablets differed from 50% chance. For those tablets identified in the different solutions, another test on proportions was used to determine whether the type of solution made a difference. Since 3 options were available, we used a probability of 33.3%.

Results

Thirty-seven EPs completed the study. All (37/37) EP’s correctly identified the absence of tablets in the bag containing only water, and the presence of ECA in the bags containing water and PEG. For Part 2 of the study, most participants - 25/37 (67.5%) using water, 23/37 (62.1%) using PEG, and all 37 (100%) using AC - underestimated the number of ECA pills in solution by at least 50%.

Conclusion

There may be a potential role for POCUS in the evaluation of patients suspected of acute, massive ingested OD. EPs accurately identified the presence of ECA in water and PEG, but underestimated the number of tablets in all tested solutions.