The role of ultrasound in the management of intestinal obstruction

Point of Care Abdominal Ultrasound

Abdominal pain is a common emergency department complaint, and point-of-care ultrasound (POCUS) of the abdomen is increasingly being utilized to evaluate clinical manifestations. It aids in accurate diagnoses and assists in procedures, particularly in emergency and critical care settings. Imaging is often required to confirm the etiology of abdominal pain. POCUS provides the benefit of avoiding radiation exposure and enables quicker diagnosis compared to computed tomography scans. There is growing evidence of the diagnostic accuracy for numerous abdominal POCUS applications, including appendicitis, intussusception, diverticulitis, gastric ultrasound and contrast-enhanced ultrasound.

Role of point-of-care ultrasound in critical care and emergency medicine: update and future perspective

Point-of-care ultrasound (POCUS) is a rapidly developing technology that has the potential to revolutionize emergency and critical care medicine. The use of POCUS can improve patient care by providing real-time clinical information. However, appropriate usage and proper training are crucial to ensure patient safety and reliability. This article discusses the various applications of POCUS in emergency and critical care medicine, the importance of training and education, and the future of POCUS in medicine.

Imaging of Gastrointestinal Tract Ailments

Gastrointestinal (GI) disorders comprise a diverse range of conditions that can significantly reduce the quality of life and can even be life-threatening in serious cases. The development of accurate and rapid detection approaches is of essential importance for early diagnosis and timely management of GI diseases. This review mainly focuses on the imaging of several representative gastrointestinal ailments, such as inflammatory bowel disease, tumors, appendicitis, Meckel's diverticulum, and others. Various imaging modalities commonly used for the gastrointestinal tract, including magnetic resonance imaging (MRI), positron emission tomography (PET) and single photon emission computed tomography (SPECT), and photoacoustic tomography (PAT) and multimodal imaging with mode overlap are summarized. These achievements in single and multimodal imaging provide useful guidance for improved diagnosis, staging, and treatment of the corresponding gastrointestinal diseases. The review evaluates the strengths and weaknesses of different imaging techniques and summarizes the development of imaging techniques used for diagnosing gastrointestinal ailments.

Progress in diagnosis and treatment of surgery-related adhesive small intestinal obstruction

Adhesive small bowel obstruction is a relatively common surgical acute abdomen, which is caused by various factors that result in the contents of the small bowel failing to pass smoothly. The clinical symptoms include abdominal pain, distension, nausea and vomiting, and defecation disorder. The chance of adhesive small bowel obstruction to develop in patients with a history of abdominal surgery is around 2.4%. This paper discusses the most recent developments in the conservative and surgical management of adhesive small bowel obstruction based on clinical manifestation, laboratory analysis, and imaging examination.

Point-of-Care Abdominal Ultrasonography (POCUS) on the Way to the Right and Rapid Diagnosis

Point-of-Care ultrasound (POCUS) is based on target ultrasound that is performed wherever a patient is being treated, and by a non-radiologist directly involved in the patient’s care. It is used either for quick diagnosis or procedural guidance. Abdominal pain is one of the most common complaints in emergency departments, and POCUS can help in the differentiation of patients who need additional diagnostic tests or hospital treatment, which eventually reduces the overall costs of health care. POCUS has high sensitivity and specificity in abdominal pathology, it can be helpful in the evaluation of biliary, intestinal, and urinary tract, and it is especially used in trauma. Additionally, the gold standard for abdominal aortic aneurysm detection, follow up and screening is precisely this diagnostic procedure. Unfortunately, the quality of ultrasound examination can be affected by the experience of the physician performing it and the patient’s body weight. There is no doubt that POCUS is being increasingly recognized, but all motivated physicians should be provided with dedicated tutors and enough time for learning. This would certainly help to implement this diagnostic method as a routine in emergency and critical care departments, and significantly shorten the time until definitive diagnosis.

Point-of-care ultrasound-first for the evaluation of small bowel obstruction: National cost savings, length of stay reduction, and preventable radiation exposure

OBJECTIVES

Computed tomography (CT) has long been the gold standard in diagnosing patients with suspected small bowel obstruction (SBO). Recently, point-of-care ultrasound (POCUS) has demonstrated comparable test characteristics to CT imaging for the diagnosis of SBO. Our primary objective was to estimate the annual national cost saving impact of a POCUS-first approach for the evaluation of SBO. Our secondary objectives were to estimate the reduction in radiation exposure and emergency department (ED) length of stay (LOS).

METHODS

We created and ran 1000 trials of a Monte Carlo simulation. The study population included all patients presenting to the ED with abdominal pain who were diagnosed with SBO. Using this simulation, we modeled the national annual cost savings in averted advanced imaging from a POCUS-first approach for SBO. The model assumes that all patients who require surgery or have non-diagnostic POCUS exams undergo CT imaging. The model also conservatively assumes that a subset of patients with diagnostic POCUS exams undergo additional confirmatory CT imaging. We used the same Monte Carlo model to estimate the reduction in radiation exposure and total ED bed hours saved.

RESULTS

A POCUS-first approach for diagnosing SBO was estimated to save a mean (±SD) of $30.1 million (±8.9 million) by avoiding 143,000 (±31,000) CT scans. This resulted in a national cumulative decrease of 507,000 bed hours (±268,000) in ED LOS. The reduction in radiation exposure to patients could potentially prevent 195 (±56) excess annual cancer cases and 98 (±28) excess annual cancer deaths.

CONCLUSIONS

If adopted widely and used consistently, a POCUS-first algorithm for SBO could yield substantial national cost savings by averting advanced imaging, decreasing ED LOS, and reducing unnecessary radiation exposure in patients. Clinical decision tools are needed to better identify which patients would most benefit from CT imaging for SBO in the ED.

Future developments in the imaging of the gastrointestinal tract: the role of ultrasound

PURPOSE OF REVIEW

The purpose of this review is to summarize the utilization and most recent developments with regard to the use of ultrasound when imaging the abdomen and gastrointestinal tract.

RECENT FINDINGS

Although the use of ultrasound to assess the anatomy of the various abdominal organs is well established within radiology and critical care, its use as part of functional and physiological assessment is still evolving. Recent developments have extended the use of ultrasound beyond standard B-mode/2D imaging techniques to incorporate more functional and haemodynamic assessment. These include the use of contrast-enhanced ultrasound (CEUS), elastography, and colour Doppler techniques.

SUMMARY

Whilst Doppler techniques are reasonably well established within critical care ultrasound (CCUS), especially in echocardiography, CEUS and elastography are less well known. CEUS utilizes a purely intravascular contrast agent whilst elastography measures the degree of deformation or stiffness in various organs. Whilst their use individually may be limited; they may play a role in a multiparametric assessment. Mirroring the overall trends in critical care ultrasound development, abdominal ultrasound assessment is best integrated in a holistic approach and adapted to the individual patient.

Diagnostic accuracy of ultrasound for small bowel obstruction: A systematic review and meta-analysis

PURPOSE

Accurate diagnosis of small bowel obstruction (SBO) remains challenging. The evidence of the diagnostic accuracy of ultrasound varies among studies, with reporting sensitivity ranging from 82 % to 100 % and specificity ranging from 54 % to 100 %. The aim of our study is to perform a systematic review and meta-analysis to investigate the accuracy of ultrasound for diagnosing SBO.

METHOD

The PubMed, EMBASE, Cochrane Library, Web of Science, and Scopus databases were searched from database inception to March 2020. Randomized controlled trials, quasi randomized studies, and prospective or retrospective cohort studies that evaluated the diagnostic performance of ultrasound for the diagnosis of bowel obstruction in adult patients (age ≥ 16 years) were eligible. The QUADAS-2 tool was used to assess the quality of the included studies. The pooled sensitivities, specificities were analyzed using a bivariate random-effects model. (PROSPERO ID: CRD42020170010).

RESULTS

Fifteen studies, with most rating as a moderate risk of bias, met the inclusion criteria. The pooled sensitivity and specificity were 92 % (95 % CI: 89%-95%) and 93 % (95 % CI: 85%-97%), respectively. Subgroup analysis revealed no significant differences in sensitivity when ultrasound was performed on different continents, in different settings, and under different reference standards. However, the specificity was significantly lower when ultrasound was performed in the North America, in the emergency department, and when computed tomography was used as the only reference standard.

CONCLUSIONS

Overall, ultrasound is a highly sensitive and specific tool for the diagnosis of SBO. Using ultrasound to rule in patients with SBO should be used with caution, as variations in the specificity were observed in different study setting, operators from different continents and reference standards used.

The role of point of care ultrasound in radiology department: update and prospective. A statement of Italian college ultrasound

Ultrasound, in its new point-of-care conception, has been called the stethoscope of the future. Goal-directed bedside ultrasound examination, performed by a healthcare provider to answer a specific diagnostic question or guide an invasive procedure, is currently revolutionizing medical practice. It is used by various specialties in multiple clinical contexts for procedural, diagnostic, and screening applications. Point-of-care ultrasound is also a strategic technique in clinical radiology; it brings the radiologist closer to the patient (in interaction and understanding) like interventional and angiography procedures and, as an integrative imaging modality, is a vital radiological tool for decision-making in many situations. In this commentary, we present our observations on the use of ultrasound, in a sincere appeal to refrain from omitting ultrasound as a diagnostic technique in this era of deep professional change, in which radiologists must return to being a true clinical semiologist.

Adhesive Small Bowel Obstruction: Predictive Radiology to Improve Patient Management

Adhesive small bowel obstruction (SBO) remains one of the leading causes of emergency room visits and is still associated with high morbidity and mortality rates. Because the management of adhesive SBO has shifted from immediate surgery to nonoperative treatment in the absence of ischemia, it is crucial to rapidly detect or predict strangulation, which requires emergent surgery. CT is now established as the best imaging technique for the initial assessment of patients suspected of having adhesive SBO. CT helps confirm the diagnosis of mechanical SBO, locate the site of obstruction, establish the cause, and detect complications. This article is a review of the role of imaging in answering specific questions to help predict the management needs of each individual patient. It includes (a) an update on the best CT signs for predicting ischemia and a need for bowel resection; (b) a discussion of the CT features that help differentiate open-loop from closed-loop obstruction and a single adhesive band from matted adhesions and how these differences can influence the management; and (c) a review of the main CT predictors of the success or failure of nonoperative management in adhesive SBO.

Rolling in the Deep: Imaging Findings and Diagnostic Pearls in Gallstone Ileus

Gallstone ileus is a dramatic complication of gallstone disease, uncommon but not exceptional in a busy emergency department. It represents a cause of mechanical intestinal obstruction, which predominantly occurs in elderly and frail patients; this contributes to the high morbidity and mortality rates associated with this condition. The modern radiologist is frequently asked to determine the cause of bowel obstruction and should be aware of the most pictorial features of this unusual disease. Broadly speaking, abdominal radiography and ultrasonography alone are limited in detecting the cause of bowel obstruction, but the sensitivity for the preoperative diagnosis of gallstone ileus may be improved by combining the findings obtained by both techniques. Computed tomography is the modality of choice for the diagnosis of this disease: it may accurately describe the number, size, and location of migrated gallstones and the exact site of bowel obstruction, providing a detailed preoperative planning. Magnetic resonance imaging may be used in selected cases for an exquisite anatomic definition of the fistulous communication.

Nongynecologic Causes of Pelvic Pain: Ultrasound First

Ultrasonography (US) is often the first-line imaging study used to evaluate women who present with acute or chronic pelvic pain. Detection of nongynecologic causes of pelvic pain is critical, because delay in diagnosis can cause significant morbidity and mortality. Evaluation of these entities requires a variety of transducers to achieve optimal imaging depth and changes in patient positioning. Specific imaging techniques (such as graded compression) may be required if bowel pathology is suspected. Contrast-enhanced ultrasonography is increasingly used to improve detection of certain entities. The US appearance of common gastrointestinal and urinary tract-related causes of pelvic pain is reviewed.

Diagnostic Accuracy of Ultrasound in the Diagnosis of Small Bowel Obstruction

INTRODUCTION

Small bowel obstruction (SBO) is a common presentation to the Emergency Department (ED). This study aimed to analyze the accuracy of ultrasound (US) in diagnosing and staging SBO.

OBJECTIVES

The main object of this study was to analyze the accuracy of ultrasound in diagnosing and staging SBO compared to CT.

METHODS

Retrospectively, stable patients with an ultrasonographic diagnosis of SBO who underwent abdominal CT immediately after US and before receiving naso-intestinal decompression, were included. US criteria for the diagnosis of SBO were related to morphological and functional findings. US diagnosis of obstruction was made if fluid-filled dilated small bowel loops were detected, peristalsis was abnormal and parietal abnormalities were present. Morphologic and functional sonographic findings were assigned to three categories: simple SBO, compensated SBO and decompensated SBO. US findings were compared with the results of CT examinations: Morphologic CT findings (divided into loop, vascular, mesenteric and peritoneal signs) allowed the classification of SBO in simple, decompensated and complicated.

RESULTS

US diagnostic accuracy rates in relation to CT results were calculated: ultrasound compared to CT imaging, had a sensitivity of 92.31% (95% CI, 74.87% to 99.05%) and a specificity of 94.12% (95% CI, 71.31% to 99.85%) in the diagnosis of SBO.

CONCLUSIONS

This study, similarly to the existing literature, suggests that ultrasound is highly accurate in the diagnosis of SBO, and that the most valuable sonographic signs are the presence of dilated bowel loops ad abnormal peristalsis.

Diagnostic point-of-care ultrasound (POCUS) for gastrointestinal pathology: state of the art from basics to advanced

The use of point-of-care ultrasound (POCUS) by non-radiologists has dramatically increased. POCUS is completely different from the routine radiological studies. POCUS is a Physiological, On spot, extension of the Clinical examination, that is Unique, and Safe. This review aims to lay the basic principles of using POCUS in diagnosing intestinal pathologies so as to encourage acute care physicians to learn and master this important tool. It will be a useful primer for clinicians who want to introduce POCUS into their clinical practice. It will cover the basic physics, technical aspects, and simple applications including detection of free fluid, free intraperitoneal air, and bowel obstruction followed by specific POCUS findings of the most common intestinal pathologies encountered by acute care physicians including acute appendicitis, epiploic appendagitis, acute diverticulitis, pseudomembranous colitis, intestinal tuberculosis, Crohn’s disease, and colonic tumours. Deep understanding of the basic physics of ultrasound and its artefacts is the first step in mastering POCUS. This helps reaching an accurate POCUS diagnosis and avoiding its pitfalls. With increased skills, detailed and accurate POCUS findings of specific intestinal pathologies can be achieved and properly correlated with the clinical picture. We have personally experienced and enjoyed this approach to a stage that an ultrasound machine is always accompanying us in our clinical on calls and rounds.

Bologna guidelines for diagnosis and management of adhesive small bowel obstruction (ASBO): 2017 update of the evidence-based guidelines from the world society of emergency surgery ASBO working group

Background

Adhesive small bowel obstruction (ASBO) is a common surgical emergency, causing high morbidity and even some mortality. The adhesions causing such bowel obstructions are typically the footprints of previous abdominal surgical procedures. The present paper presents a revised version of the Bologna guidelines to evidence-based diagnosis and treatment of ASBO. The working group has added paragraphs on prevention of ASBO and special patient groups.

Methods

The guideline was written under the auspices of the World Society of Emergency Surgery by the ASBO working group. A systematic literature search was performed prior to the update of the guidelines to identify relevant new papers on epidemiology, diagnosis, and treatment of ASBO. Literature was critically appraised according to an evidence-based guideline development method. Final recommendations were approved by the workgroup, taking into account the level of evidence of the conclusion.

Recommendations

Adhesion formation might be reduced by minimally invasive surgical techniques and the use of adhesion barriers. Non-operative treatment is effective in most patients with ASBO. Contraindications for non-operative treatment include peritonitis, strangulation, and ischemia. When the adhesive etiology of obstruction is unsure, or when contraindications for non-operative management might be present, CT is the diagnostic technique of choice. The principles of non-operative treatment are nil per os, naso-gastric, or long-tube decompression, and intravenous supplementation with fluids and electrolytes. When operative treatment is required, a laparoscopic approach may be beneficial for selected cases of simple ASBO.Younger patients have a higher lifetime risk for recurrent ASBO and might therefore benefit from application of adhesion barriers as both primary and secondary prevention.

Discussion

This guideline presents recommendations that can be used by surgeons who treat patients with ASBO. Scientific evidence for some aspects of ASBO management is scarce, in particular aspects relating to special patient groups. Results of a randomized trial of laparoscopic versus open surgery for ASBO are awaited.

A Novel Intestine Model Apparatus for Drug Dissolution Capable of Simulating the Peristaltic Action

A novel dissolution apparatus has been proposed as an alternative apparatus for dissolution testing. In this study, we evaluated the performance of the new intestine model for simulating the peristaltic action (IMSPA), generating the movement that closely mimics peristaltic contractions of the small intestine. Two polyethylene oxide matrix tablet formulations, containing a model drug belonging to class III of the Biopharmaceutics Classification System, were tested. Dissolution was also performed in the USP2 apparatus. The release profiles were further compared to the in vivo data to evaluate the in vivo relevance of the new apparatus. The results demonstrated that the novel apparatus showed good discriminatory power between different polyethylene oxide formulations. Moreover, a better relation to the in vivo data was established by the IMSPA as compared to the USP2 apparatus. In conclusion, the model parameters were efficiently controlled to ensure the dissolution conditions crucial for evaluating the in vivo release performance of the tested formulations.

Current Role of Ultrasound in Small Bowel Imaging

Bowel ultrasound is cheap, relatively quick, allows dynamic evaluation of the bowel, has no radiation burden, is well tolerated by patients, and allows repeat imaging. Bowel ultrasound requires a systematic assessment of the entire bowel using high-frequency probes. In addition, hydrosonography and contrast-enhanced ultrasound may be performed. We present the normal sonographic appearances of large and small bowel and the sonographic appearances of acute appendicitis, Crohn's disease, celiac disease, intussusception, infectious enteritis, intestinal tuberculosis, small bowel ileus and obstruction, small bowel ischemia, and malignant tumors.

Magnetic Resonance Imaging of Abdominal and Pelvic Pain in the Pregnant Patient

The utility of MR imaging in evaluating abdominal and pelvic pain in the pregnant patient is discussed. Details regarding the indications, technical aspects, and imaging findings of various common abdominal and pelvic abnormalities in pregnancy are reviewed.

Clinician-performed abdominal sonography

INTRODUCTION

Point-of-care ultrasonography is increasingly utilized across a wide variety of physician specialties. This imaging modality can be used to evaluate patients rapidly and accurately for a wide variety of pathologic conditions.

METHODS

A literature search was performed for articles focused on clinician-performed ultrasonography for the diagnosis of appendicitis, gallbladder disease, small bowel obstruction, intussusception, and several types of renal pathology. The findings of this search were summarized including the imaging techniques utilized in these studies.

CONCLUSION

Clinician performed point-of-care sonography is particularly well suited to abdominal applications. Future investigations may further confirm and extend its utility at the bedside.

Transabdominal ultrasonography of the small bowel

In the era of double balloon enteroscopy, capsule endoscopy, CT, and MRI enterography is transabdominal ultrasonography (TUS) underestimated method for evaluation of small bowel pathology. As often initial imagine method in abdominal complaints, nowadays has TUS much better diagnostic potential than two decades ago. High-resolution ultrasound probes with harmonic imaging significantly improve resolution of bowel wall in real time, with possibility to asses bowel peristalsis. Color flow doppler enables evaluation of intramural bowel vascularisation, pulse wave doppler helps to quantificate flow in coeliac and superior mesenteric arteries. Small intestine contrast ultrasonography with oral contrast fluid, as well as contrast enhanced ultrasonography with intravenous microbubble contrast also improves small bowel imaging. We present a review of small intestine pathology that should be detected during ultrasound examinations, discuss technical requirements, advantages and limitations of TUS, typical ultrasound signs of Crohn's disease, ileus, celiac disease, intussusception, infectious enteritis, tumours, ischemic and haemorrhagic conditions of small bowel. In the hands of experienced investigator, despite some significant limitations(obesity, meteorism), is transabdominal ultrasonography reliable, noninvasive and inexpensive alternative method to computerised tomography (CT) and magnetic resonance imaging (MRI) in small bowel examination.