Accuracy of abdominal auscultation for bowel obstruction

Sonographic Evaluation of Gastric Residual Volume during Enteral Nutrition in Critically Ill Patients Using a Miniaturized Ultrasound Device

Background: To assess the risk of aspiration, nutrient tolerance, and gastric emptying of patients in ICUs, gastric ultrasound can provide information about the gastric contents. Using established formulas, the gastric residual volume (GRV) can be calculated in a standardized way by measuring the gastric antrum. The purpose of this study was to determine the GRV in a cohort of enterally fed patients using a miniaturized ultrasound device to achieve knowledge about feasibility and the GRV over time during the ICU stay. The findings could contribute to the optimization of enteral nutrition (EN) therapy. Methods: A total of 217 ultrasound examinations with 3 measurements each (651 measurements in total) were performed twice daily (morning and evening) in a longitudinal observational study on 18 patients with EN in the interdisciplinary surgical ICU of Saarland University Medical Center. The measured values of the GRV were analyzed in relation to the clinical course, the nutrition, and other parameters. Results: Measurements could be performed without interrupting the flow of clinical care and without pausing EN. The GRV was significantly larger with sparsely auscultated bowel sounds than with normal and excited bowel sounds (p < 0.01). Furthermore, a significantly larger GRV was present when using a high-caloric/low-protein nutritional product compared to an isocaloric product (p = 0.02). The GRV at the morning and evening measurements showed no circadian rhythm. When comparing the first and last ultrasound examination of each patient, there was a tendency towards an increased GRV (p = 0.07). Conclusion: The GRV measured by miniaturized ultrasound devices can provide important information about ICU patients without restricting treatment procedures in the ICU. Measurements are possible while EN therapy is ongoing. Further studies are needed to establish gastric ultrasound as a management tool in nutrition therapy.

Automated Bowel Sound Analysis: An Overview

Despite technological progress, we lack a consensus on the method of conducting automated bowel sound (BS) analysis and, consequently, BS tools have not become available to doctors. We aimed to briefly review the literature on BS recording and analysis, with an emphasis on the broad range of analytical approaches. Scientific journals and conference materials were researched with a specific set of terms (Scopus, MEDLINE, IEEE) to find reports on BS. The research articles identified were analyzed in the context of main research directions at a number of centers globally. Automated BS analysis methods were already well developed by the early 2000s. Accuracy of 90% and higher had been achieved with various analytical approaches, including wavelet transformations, multi-layer perceptrons, independent component analysis and autoregressive-moving-average models. Clinical research on BS has exposed their important potential in the non-invasive diagnosis of irritable bowel syndrome, in surgery, and for the investigation of gastrointestinal motility. The most recent advances are linked to the application of artificial intelligence and the development of dedicated BS devices. BS research is technologically mature, but lacks uniform methodology, an international forum for discussion and an open platform for data exchange. A common ground is needed as a starting point. The next key development will be the release of freely available benchmark datasets with labels confirmed by human experts.

Imaging Modalities for Evaluation of Intestinal Obstruction

It is essential for the colon and rectal surgeon to understand the evaluation and management of patients with both small and large bowel obstructions. Computed tomography is usually the most appropriate and accurate diagnostic imaging modality for most suspected bowel obstructions. Additional commonly used imaging modalities include plain radiographs and contrast imaging/fluoroscopy, while less commonly utilized imaging modalities include ultrasonography and magnetic resonance imaging. Regardless of the imaging modality used, interpretation of imaging should involve a systematic, methodological approach to ensure diagnostic accuracy.

Point-of-care ultrasound (POCUS) for hospitalists and general internists

Point-of-care ultrasound (POCUS) is currently implemented in various medical fields by clinicians for the bedside examination of patients. Evidence supports the fact that adding an ultrasound technology in daily practice (hand-held ultrasound device), called by some 'stethoscope of the future', improves patient care and allows an earlier diagnosis in a hospital setting. In this article, we reviewed the historical evolution of the use of ultrasound in medicine and the possibilities of using POCUS for hospitalists and general internists based on the existing scientific literature.

Auscultation of Bowel Sounds and Ultrasound of Peristalsis Are Neither Compartmentalized Nor Correlated

Objective  Auscultation of bowel sounds has been taught as a component of the physical examination since the beginning of the 20th century. However, there has been little research or consensus on the significance of listening in different quadrants. Some textbooks indicate that bowel sounds are the result of peristalsis in that region, while others state that bowel sounds can be generalized over the entire abdominal wall. With ultrasonography, peristalsis can be visualized in a dynamic and non-invasive manner. The purpose of this study was to determine the relationship between auscultation of bowel sounds and visualization of peristalsis with ultrasound, to understand whether or not bowel sounds and peristalsis are compartmentalized. Methods  Study participants quietly lay supine, while one investigator positioned an ultrasound probe on the abdomen visualizing the small intestine, and a second investigator placed an EKO Digital Stethoscope (Eko Devices, Inc., Oakland, CA) directly adjacent to the probe auscultate for bowel sounds. During a two-minute interval, a third investigator noted every time a bowel sound was heard (A+), peristalsis was seen (U+), or a combined event (C+) occurred, recording the total number of events. Measurements were recorded from four quadrants (right upper quadrant {RUQ}, left upper quadrant {LUQ}, right lower quadrant {RLQ}, left lower quadrant {LLQ}) and the periumbilical region (PUR). Fisher Exact test was used to determine whether there were significant differences between the number of bowel sounds heard but not seen (A+) and those seen but not heard (U+) with sounds that were both seen and heard (C+). Significance was determined with p < 0.05. Results  A total of 16 participants were included, with a combined 973 discrete bowel events, both auscultated and visualized. No quadrant showed a significant correlation between an isolated sound (A+) or peristalsis (U+) and a combined event (C+), indicating there were many events where an auscultated sound failed to correlate with observed peristalsis, and vice versa. The average p-value was 0.544, with a range of 0.052-1.00. Conclusion  This study showed that there is no significant correlation between auscultated bowel sounds and peristalsis within a given region. This study calls into question whether auscultation of all four quadrants provides more meaningful information than auscultation of one central point of the abdomen.

Real-time bowel sound analysis using newly developed device in patients undergoing gastric surgery for gastric tumor

Background and Aim

Objective measurements are not available for determining bowel sounds. The present study sought to evaluate the efficacy of a novel bowel sound monitoring system for perioperative use in patients undergoing gastric surgery.

Methods

The study enrolled 14 patients who underwent surgery for gastric cancer at Kochi Medical School from 2017 to 2018. Preoperative and postoperative bowel sounds were recorded using a newly developed real‐time analysis system in the operating theater and recovery room. Clinical information and bowel sound count data were obtained to compare preoperative and postoperative measures.

Results

The median preoperative and postoperative bowel sound counts across all patients were 1.4 and 2.5 counts per minute (cpm), respectively. In patients who underwent laparoscopic gastrectomy, the postoperative bowel sound count was significantly higher than that recorded preoperatively (2.3 vs. 1.6 cpm, P = 0.005). The findings also revealed a significant negative correlation between postoperative bowel sound count and operation time (r = −0.714, P = 0.003).

Conclusions

The real‐time bowel sound analysis system tested herein presents a promising diagnostic tool to quantitatively evaluate bowel movements associated with surgery. Our results suggested a need for shorter operation times for gastric procedures with respect to peristalsis recovery and supported the use of minimally invasive surgery.

Are Classic Bedside Exam Findings Required to Initiate Enteral Nutrition in Critically Ill Patients: Emphasis on Bowel Sounds and Abdominal Distension

The general physical examination of a patient is an axiom of critical care medicine, but evidence to support this practice remains sparse. Given the lack of evidence for a comprehensive physical examination of the entire patient on admission to the intensive care unit, which most clinicians consider an essential part of care, should clinicians continue the practice of a specialized gastrointestinal system physical examination when commencing enteral nutrition in critically ill patients? In this review of literature related to gastrointestinal system examination in critically ill patients, the focus is on gastrointestinal sounds and abdominal distension. There is a summary of what these physical features represent, an evaluation of the evidence regarding use of these physical features in patients after abdominal surgery, exploration of the rationale for and against using the physical findings in routine practice, and detail regarding what is known about each feature in critically ill patients. Based on the available evidence, it is recommended that an isolated symptom, sign, or bedside test does not provide meaningful information. However, it is submitted that a comprehensive physical assessment of the gastrointestinal system still has a role when initiating or administering enteral nutrition: specifically, when multiple features are present, clinicians should consider further investigation or intervention.

Changes in bowel sounds of inpatients undergoing general anesthesia

BACKGROUND

General anesthesia can affect intestinal function, but there is no objective, practical and effective indicator to evaluate the inhibition and recovery of intestinal function. The main objectives of this study were to assess whether bowel sounds (BSs) changed before, immediately after and 3 h after general anesthesia, and whether these changes in BSs are an effective indicator of intestinal function and an accurate guide for postoperative feeding.

METHODS

We randomly selected 26 inpatients and collected three sets of 5-min continuous BS data before the operation (Pre-op), immediately after the operation (Pro-op) and 3 h after the operation (3 h-Pro-op) for each patient. Then, the linear and nonlinear characteristic values (CVs) of each effective bowel sound were extracted and paired t tests and rank-sum tests were used to evaluate the changes in the BSs.

RESULTS

The differences in CVs, between Pre-op and Pro-op, as well as between Pro-op and 3 h-Pro-op, were statistically significant (p < 0.05). However, there are no statistically significant differences between all the CVs between Pre-op and 3 h-Pro-op (p > 0.05).

CONCLUSION

BSs change before and after general anesthesia. Furthermore, the BSs are weakened due to general anesthesia and recover to the pre-op state 3 h later. Therefore, the BSs can be an indicator of intestinal function under general anesthesia, so as to provide guidance for postoperative feeding, which is of considerable clinical significance.

Adhesive small bowel obstruction - an update

Small bowel obstruction (SBO) accounts for 12-16% of emergency surgical admissions and 20% of emergency surgical procedures. Even with the advent of laparoscopic surgery, intra-abdominal adhesions remain a significant cause of SBO, accounting for 65% of cases. History and physical examination are essential to identify signs of bowel ischemia as this indicates a need for urgent surgical exploration. Another critical aspect of evaluation includes establishing the underlying cause for obstruction and distinguishing between adhesive and non-adhesive etiologies as adhesive SBO (ASBO) can be managed non-operatively in 70-90% of patients. A patient with a history of abdominopelvic surgery along with one or more cardinal features of obstruction should be suspected to have ASBO until proven otherwise. Triad of severe pain, pain out of proportion to the clinical findings, and presence of an abdominal scar suggest possible closed-loop obstruction. Computed tomography has higher sensitivity and specificity compared to plain films and is recommended by the Bologna guidelines. Correcting fluid and electrolyte imbalance is an initial crucial step to mitigate severe hypovolemia. Patients should proceed with surgery if symptoms of bowel compromise are present, or if symptoms do not resolve or have worsened. Surgery is indicated in patients with ischemia, strangulation, perforation, peritonitis, or failure of non-operative treatment. With advances in minimal access technology and increasing experience, laparoscopic adhesiolysis is recommended. Mechanical adhesion barriers are an effective measure to prevent adhesion formation.

The potential of computerised analysis of bowel sounds for diagnosis of gastrointestinal conditions: a systematic review

BACKGROUND

Gastrointestinal (GI) conditions are highly prevalent, and their standard diagnostic tests are costly and carry risks. There is a need for new, cost-effective, non-invasive tests. Our main objective was to assess the potential for use of bowel sounds computerised analysis in the diagnosis of GI conditions.

METHODS

The systematic review followed the PRISMA requirements. Searches were made of four databases (PubMed, MEDLINE, Embase, and IEEE Xplore) and the references of included papers. Studies of all types were included. The titles and abstracts were screened by one author. Full articles were reviewed and data collected by two authors independently. A third reviewer decided on inclusion in the event of disagreement. Bias and applicability were assessed via a QUADAS tool adapted to accommodate studies of multiple types.

RESULTS

Two thousand eight hundred eighty-four studies were retrieved; however, only 14 studies were included. Most of these simply assessed associations between a bowel sound feature and a condition. Four studies also included assessments of diagnostic accuracy. We found many significant associations between a bowel sound feature and a GI condition. Receiver operating characteristic curve analyses revealed high sensitivity and specificity for an irritable bowel syndrome test, and a high negative predictive value for a test for post-operative ileus. Assessment of methodological quality identified weaknesses in all studies. We particularly noted a high risk of bias in patient selection. Because of the limited number of trials included and the variety in conditions, technology, and statistics, we were unable to conduct pooled analyses.

CONCLUSIONS

Due to concerns over quality and small sample sizes, we cannot yet recommend an existing BSCA diagnostic test without additional studies. However, the preliminary results found in the included studies and the technological advances described in excluded studies indicate excellent future potential. Research combining sophistical clinical and engineering skills is likely to be fruitful.

SYSTEMATIC REVIEW REGISTRATION

The review protocol (review ID number 42016054028) was developed by three authors (AI, KMW, and JM) and was published in the PROSPERO International prospective register of systematic reviews. It can be accessed from https://www.crd.york.ac.uk/PROSPERO/ .

Adhesive Closed-loop Small Bowel Obstruction

Complete small bowel obstruction (SBO) is a common surgical emergency often resulting from adhesive bands that form following iatrogenic peritoneal injury. Rarely, adhesive SBO may arise without previous intra-abdominal surgery through other modes of peritoneal trauma. We present the case of a male evaluated in the emergency department for a closed-loop small bowel obstruction due to an adhesive band that likely formed after blunt abdominal trauma over two decades earlier. We review the epidemiology, pathophysiology, and treatment options for similar cases of adhesive SBO.