Usefulness of bowel sound auscultation: a prospective evaluation

A Nomogram for Predicting Surgical Timing in Neonates with Necrotizing Enterocolitis

OBJECTIVE

To explore the surgical risk variables in patients with necrotizing enterocolitis (NEC) and develop a nomogram model for predicting the surgical intervention timing of NEC.

METHODS

Infants diagnosed with NEC were enrolled in our study. We gathered information from clinical data, laboratory examinations, and radiological manifestations. Using LASSO (least absolute shrinkage and selection operator) regression analysis and multivariate logistic regression analysis, a clinical prediction model based on the logistic nomogram was developed. The performance of the nomogram model was evaluated using the receiver operating characteristic (ROC) curve, calibration curves, and decision curve analysis (DCA).

RESULTS

A surgical intervention risk nomogram based on hypothermia, absent bowel sounds, WBC > 20 × 10⁹/L or < 5 × 10⁹/L, CRP > 50 mg/L, pneumatosis intestinalis, and ascites was practical, had a moderate predictive value (AUC > 0.8), improved calibration, and enhanced clinical benefit.

CONCLUSIONS

This simple and reliable clinical prediction nomogram model can help physicians evaluate children with NEC in a fast and effective manner, enabling the early identification and diagnosis of children at risk for surgery. It offers clinical revolutionary value for the development of medical or surgical treatment plans for children with NEC.

Practicing Digital Gastroenterology through Phonoenterography Leveraging Artificial Intelligence: Future Perspectives Using Microwave Systems

Production of bowel sounds, established in the 1900s, has limited application in existing patient-care regimes and diagnostic modalities. We review the physiology of bowel sound production, the developments in recording technologies and the clinical application in various scenarios, to understand the potential of a bowel sound recording and analysis device-the phonoenterogram in future gastroenterological practice. Bowel sound production depends on but is not entirely limited to the type of food consumed, amount of air ingested and the type of intestinal contractions. Recording technologies for extraction and analysis of these include the wavelet-based filtering, autoregressive moving average model, multivariate empirical mode decompression, radial basis function network, two-dimensional positional mapping, neural network model and acoustic biosensor technique. Prior studies evaluate the application of bowel sounds in conditions such as intestinal obstruction, acute appendicitis, large bowel disorders such as inflammatory bowel disease and bowel polyps, ascites, post-operative ileus, sepsis, irritable bowel syndrome, diabetes mellitus, neurodegenerative disorders such as Parkinson's disease and neonatal conditions such as hypertrophic pyloric stenosis. Recording and analysis of bowel sounds using artificial intelligence is crucial for creating an accessible, inexpensive and safe device with a broad range of clinical applications. Microwave-based digital phonoenterography has huge potential for impacting GI practice and patient care.

Graphene-based strain sensor with sandwich structure and its application in bowel sounds monitoring

Surgery is one of the primary treatment modalities for gastrointestinal tumors but can lead to postoperative ileus (POI), which can aggravate pain and increase costs. The incidence of POI can be effectively reduced by monitoring bowel sounds to assist doctors in deciding the timing of transoral feeding. In this study, we prepared a flexible strain sensor based on a graphene composite material and tested the feasibility of sensor monitoring of bowel sounds using simultaneous stethoscope and sensor monitoring. We found that the time of hearing the bowel sounds (12.0–12.1 s) corresponded to the time of waveform change monitored by the sensor (12.036 s), and the sound tone magnitude corresponded to the waveform amplitude. This proves that the application of sensors to monitor bowel sounds is feasible, which opens up a new field for the application of graphene sensors and provides a new way for clinicians to judge the condition of the intestine.

Combining medicine and materials science. First application of graphene strain sensors for monitoring bowel sounds

Systematic Review of Definitions and Outcome Measures for Postoperative Ileus and Return of Bowel Function after Abdominal Surgery in Children

This review aims to objectify which definitions and outcome measures are used for the return of bowel function and postoperative ileus in children. PubMed and Embase were systematically searched from inception to December 17, 2020. Prospective studies conducted in children (aged 0-18 years) undergoing gastrointestinal surgery which reported on definitions and/or outcome measures for post-operative ileus or return of bowel function were evaluated. Definitions and outcome measures were extracted. From 4,027 references, 71 articles were included. From the 17 articles mentioning postoperative ileus, 8 (47%) provided a definition. In total, 34 outcome measures were used and 12 were unique. "Abdominal distension" was the most reported (41%) measure. In 41%, the outcome measures only described the return of gastric motility, while 18% described the return of intestinal motility. The return of bowel function was mentioned in 67 articles, none provided a definition. In total, 133 outcome measures were used and 37 were unique. Time to oral intake was the most reported (14%) measure. In 49%, the outcome measures only described the return of gastric motility, while 10% described the return of intestinal motility. High variation in definitions and outcome measures has limited the generalizability of research into postoperative bowel function in children. Without standardization, it will be impossible to compare research results and evaluate treatments. In children, the return of gastric motility seemingly should get more focus compared to adults. Therefore, we believe that a definition of postoperative ileus with an accompanying core outcome set, developed by a multidisciplinary team, specifically for children is required.

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.

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.

Evaluation of Perioperative Intestinal Motility Using a Newly Developed Real-Time Monitoring System During Surgery

BACKGROUND

This study aimed to investigate perioperative intestinal motility using a novel bowel sound monitoring system in patients undergoing breast and neck surgery.

MATERIALS AND METHODS

This study enrolled 52 patients who underwent surgery for breast cancer, thyroid tumor, and parathyroid tumor at Kochi Medical School from May 2019 to June 2020. Perioperative bowel sound counts (BSCs) were recorded using a newly developed real-time analysis system in the operating theater. Clinical information and BSC per minute (cpm) data during the preanesthetic, preoperative, operative, postoperative periods, and period in recovery room were obtained to compare between each period. The Mann-Whitney U and Pearson Chi-square tests were used in data analysis.

RESULTS

The BSCs during the intraoperative period and postoperative period were significantly decreased compared to those during the preanesthetic period (0.07 cpm versus [vs.]. 1.4 cpm, P = 0.002 and 0.1 cpm vs. 1.4 cpm, P = 0.025, respectively). The preoperative BSC with a preanesthetic BSC < 1.4 was significantly lower than that with a preanesthetic BSC ≥ 1.4 (0.40 cpm vs. 1.78 cpm, P = 0.006). The preanesthetic, preoperative, and postoperative BSCs with an intraoperative BSC < 0.07 were significantly lower than those with an intraoperative BSC ≥ 0.07 (0.48 cpm vs. 2.83 cpm, P = 0.007; 0.40 cpm vs. 1.81 cpm, P = 0.008; and 0.07 cpm vs. 0.42 cpm, P = 0.006, respectively).

CONCLUSION

The real-time bowel sound analysis system demonstrated an inhibitory effect associated with anesthetic and surgical stress on intestinal motility as the BSC sequentially.

Abdominal palpation and percussion maneuvers do not affect bowel sounds

Objectives

Medical textbooks suggest that the frequency of bowel sounds may be altered by performing auscultation after palpation or percussion. We hypothesize that the frequency of bowel sounds is not affected by the order of abdominal examination.

Material and Methods

Both healthy volunteers (n= 80) and patients (n= 100) were enrolled in this crossover randomized study. Two different examination orders, one as inspection, palpation, percussion, auscultation (IPPA) and the other order as inspection, auscultation, palpation, percussion (IAPP) were used by two observers, one of which was blinded to the order of the physical examination and only performed auscultation. Bowel motilities of 40 participants were analyzed with duplex Doppler USG by a radiologist. The effects of changing the order of abdominal examination and palpation-percussion maneuvers on the frequency of bowel sounds were evaluated.

Results

Gender distribution was similar between the healthy patients and controls, and mean age of the entire study population was 47 (18-60) years. Differences between the mean bowel sound frequencies for abdominal examinations in order IPPA-IAPP versus IAPP-IPPA were evaluated for both healthy subjects and the patients. There were no differences between the first and second listening, nor were there differences between examinations performed in either order. Duplex Doppler Ultrasonographic (USG) assessments were performed on 20 healthy subjects and 20 patients before and after palpation and percussion; there were no statistically significant differences between the two listenings (p= 0.694).

Conclusion

According to both abdominal examinations and Doppler USG, the order of auscultation, whether performed before or after palpation or percussion, did not change the frequency of bowel sounds in this subject population.

The Role of Ultrasonography in Patients Referring to the Emergency Department with Acute Abdominal Pain

CONTEXT

Acute abdominal pain is a common clinical problem in emergency and non-emergency cases accounting for 5 to 10% of all referrals to the emergency department. Studies have indicated that these widely differentiated diagnoses are common to these complaints. Considering the high prevalence of this complaint in the patients and the wide range of its differential diagnosis, this review study was designed and evaluated aiming at investigating the causes of acute abdominal pain with a focus on assessing the position of ultrasound as a diagnostic tool in the emergency department.

EVIDENCE ACQUISITION

This article was conducted as a narrative review of selected articles from 2005 through 2019. By comparing them, a comprehensive review of ultrasound role was conducted in patients with acute abdominal pain referring to the emergency department.

RESULTS

In this review study, we attempted to use the articles of the clinical approach, the required laboratory tests, the disadvantages and advantages of each imaging technique, the differential diagnosis for acute abdominal pain according to the location of the pain, and the position of ultrasound as a diagnostic aid tool. Eventually, the proposed protrusion will be considered in dealing with a patient with acute abdominal pain.

CONCLUSION

Regarding the wide range of causes providing multiple differential diagnosis, as well as the limited time of the health team in the emergency department for diagnostic and therapeutic measures, particularly in time-sensitive clinical conditions, ultrasound offered by emergency medicine specialists as a diagnostic aid is considered to improve the overall diagnosis and treatment of patients, thereby reducing complications.

Gastrointestinal failure affects outcome of intensive care

PURPOSE

Goal of this study was to describe incidence and outcome of gastrointestinal failure (GIF) in ICU patients, evaluate its additive role to SOFA score in mortality prediction and describe GIF according to etiology.

MATERIALS AND METHODS

A retrospective study with prospective data collection was conducted in mixed adult ICU patients admitted 2004-2015. GIF was considered present if ≥3 of following 6 symptoms occurred in 1 day: maximum gastric residual volume ≥ 500 mL; absent bowel sounds; vomiting or regurgitation; diarrhea; suspected or radiologically confirmed bowel distension; gastrointestinal bleeding. Division into primary (gastrointestinal pathology causing GIF) and secondary (due to other conditions) GIF was made based on origin of syndrome.

RESULTS

GIF developed in 413 (10.4%) of 3959 patients. Primary GIF occurred in 61.3% and secondary GIF in 38.7% of patients. Development of GIF was associated with longer mechanical ventilation, ICU stay and higher ICU, 30-day and 90-day mortality. Outcomes of patients with primary and secondary GIF were similar. All SOFA sub-scores and number of gastrointestinal symptoms on admission day independently predicted 90-day mortality.

CONCLUSIONS

Gastrointestinal failure, independent of origin, is associated with worse ICU outcome. Similar to other organ failures included in SOFA score, GIF independently predicts mortality.

Data driven filtering of bowel sounds using multivariate empirical mode decomposition

Background

The analysis of abdominal sounds can help to diagnose gastro-intestinal diseases. Sounds originating from the stomach and the intestine, the so-called bowel sounds, occur in various forms. They are described as loose successions or clusters of rather sudden bursts. Realistic recordings of abdominal sounds are contaminated with noise and artifacts from which the bowel sounds must be differentiated.

Methods

The proposed intrinsic mode function-fractal dimension (IMF-FD) filtering utilizes the property of the multivariate empirical mode decomposition (MEMD) to behave as a series of band pass filters. The MEMD decomposes the abdominal signal into its different frequency components. The resulting intrinsic mode functions (IMFs) are modulated in amplitude and frequency where transient sonic events occur. Based on the complexity of the IMFs, measured by their fractal dimension (FD) in sliding windows, the information-carrying IMFs are selected. The filtered signal is formed as the superposition of all selected IMFs. The IMF-FD filter not only enhances the non-linear components of the original signal but also segments them from the rest. Another important aspect of this work is that typical artifacts that occur in the same frequency range as bowel sounds can be subsequently eliminated by heuristic rules.

Conclusions

The method is tested on a realistic, contaminated data set with promising performance: close to 100% of the manually labeled bowel sounds are identified.

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/ .

Secondary peritonitis: principles of diagnosis and intervention

Secondary peritonitis accounts for 1% of urgent or emergent hospital admissions and is the second leading cause of sepsis in patients in intensive care units globally. Overall mortality is 6%, but mortality rises to 35% in patients who develop severe sepsis. Despite the dramatic growth in the availability and use of imaging and laboratory tests, the rapid diagnosis and early management of peritonitis remains a challenge for physicians in emergency medicine, surgery, and critical care. In this article, we review the pathophysiology of peritonitis and its potential progression to sepsis, discuss the utility and limitations of the physical examination and laboratory and radiographic tests, and present a paradigm for the management of secondary peritonitis.

Bowel Sounds Are Not Associated With Flatus, Bowel Movement, or Tolerance of Oral Intake in Patients After Major Abdominal Surgery

BACKGROUND

Auscultation for bowel sounds has been advocated by some clinicians as a method to determine the resolution of postoperative ileus.

OBJECTIVE

Our primary aim was to prospectively evaluate the relationships between bowel sounds and the ability to tolerate oral intake in patients after major abdominal surgery. Secondarily we aimed to evaluate relationships among bowel sounds, flatus and bowel movement, and oral intake.

DESIGN

This was a prospective, blinded observational study.

SETTINGS

The study was conducted at Western Pennsylvania Hospital.

PATIENTS

A total of 124 adult patients undergoing major abdominal surgery were included.

MAIN OUTCOME MEASURES

Data were collected by medical students blinded to the purpose of the study for 10 days postoperatively or until discharge, including the presence of bowel sounds (auscultation for 1 minute), flatus, bowel movement, and tolerance of oral intake (defined as ingestion of ≥1000 mL/24 h and each subsequent day without vomiting). Associations between paired variables were determined using ϕ coefficient testing.

RESULTS

The study population consisted of 51 men and 73 women, with a mean age of 64 years (range, 20-92 y). The majority of patients (78/124 (63%)) underwent colorectal resection. The median length of hospital was 6 days. Bowel sounds were not associated with flatus, bowel movement, or tolerance of oral intake throughout the study period. The positive predictive value of bowel sounds in predicting flatus and bowel movement was low in the early postoperative period and remained <25% in predicting tolerance of oral intake throughout the study period. The analysis was repeated, including only those patients undergoing colorectal procedures, and was essentially unchanged. Flatus correlated with bowel movement in the first 6 days postoperation, but neither flatus nor bowel movement was associated with tolerance of oral intake.

LIMITATIONS

The rate of tolerance of oral intake was relatively modest throughout the study period.

CONCLUSIONS

Bowel sounds are not associated with flatus, bowel movement, or tolerance of oral intake after major abdominal surgery.

Use of bedside abdominal ultrasound to confirm intestinal motility in neonates with gastroschisis: A feasibility study

BACKGROUND

Optimal timing to begin feeds in neonates with gastroschisis remains unclear. We examined if bedside abdominal ultrasound for intestinal motility is a feasible tool to detect return of bowel function in neonates with gastroschisis.

METHODS

Neonates born with uncomplicated gastroschisis who underwent closure received daily ultrasound exams. Full motility was defined as peristalsis seen in all quadrants. Average length of time between abdominal wall closure and start of enteral feeds, full ultrasound motility, and clinical characteristics was compared using Student's t-tests.

RESULTS

Seventeen patients were enrolled. No differences were found between motility on ultrasound and bowel movements, gastric residuals, or nonbilious residuals. Mean time to enteral feeds (11.82days) was significantly delayed compared to documentation of full motility on ultrasound (8.94days; p=0.012), consistent bowel movements (8.41days; p=0.006), low gastric residuals (9.47days; p<0.001), and nonbilious residuals (9.18days; p<0.001). In the single subject in which feeds were started before full motility was seen on ultrasound, feeds were subsequently discontinued because of emesis.

CONCLUSION

Bedside abdominal ultrasound provides real-time evidence regarding intestinal motility and is a feasible tool to detect return of bowel function in neonates with gastroschisis. Future studies are needed to determine if abdominal ultrasound can shorten time to start of enteral feeds.

LEVEL OF EVIDENCE

III (diagnosis: nonconsecutive study).

Postoperative Gastrointestinal Telemetry with an Acoustic Biosensor Predicts Ileus vs. Uneventful GI Recovery

BACKGROUND

Postoperative ileus (POI) can worsen outcomes, increase cost, and prolong hospitalization. We previously found that a disposable, non-invasive acoustic gastrointestinal surveillance (AGIS) biosensor distinguishes healthy controls from patients recovering from abdominal surgery. Here, we tested whether AGIS can prospectively predict which patients will develop POI in a multicenter study.

STUDY DESIGN

AGIS is a disposable device embedded with a microphone that adheres to the abdominal wall and connects to a computer that measures acoustic intestinal rate (IR), defined as motility events/minute. We applied AGIS for 60 min before and continuously after abdominal surgery. Clinicians blinded to AGIS recordings clinically separated patients into those with vs. without POI. We used receiver operating characteristic curve analysis to calculate sensitivity, specificity, and negative predictive value (NPV) of AGIS to predict POI.

RESULTS

There were 28 subjects; nine developed POI. Median IR was 3.01/min and 4.46/min between POI and non-POI groups, respectively (P = 0.03). AGIS predicted POI onset with a sensitivity, specificity, and NPV of 63, 72, and 81%, respectively.

CONCLUSION

Non-invasive, abdominal, acoustic monitoring prospectively predicts POI. Surgeons may use AGIS to rule out POI with over 80% certainty; this offers added confidence to advance feeding earlier in those for whom it is safe.