CRPU-NET: a deep learning model based semantic segmentation for the detection of colorectal polyp in lower gastrointestinal tract

Purpose. The objectives of the proposed work are twofold. Firstly, to develop a specialized light weight CRPU-Net for the segmentation of polyps in colonoscopy images. Secondly, to conduct a comparative analysis of the performance of CRPU-Net with implemented state-of-the-art models.Methods. We have utilized two distinct colonoscopy image datasets such as CVC-ColonDB and CVC-ClinicDB. This paper introduces the CRPU-Net, a novel approach for the automated segmentation of polyps in colorectal regions. A comprehensive series of experiments was conducted using the CRPU-Net, and its performance was compared with that of state-of-the-art models such as VGG16, VGG19, U-Net and ResUnet++. Additional analysis such as ablation study, generalizability test and 5-fold cross validation were performed.Results. The CRPU-Net achieved the segmentation accuracy of 96.42% compared to state-of-the-art model like ResUnet++ (90.91%). The Jaccard coefficient of 93.96% and Dice coefficient of 95.77% was obtained by comparing the segmentation performance of the CRPU-Net with ground truth.Conclusion. The CRPU-Net exhibits outstanding performance in Segmentation of polyp and holds promise for integration into colonoscopy devices enabling efficient operation.

A phase 2 study of interleukin-22 and systemic corticosteroids as initial treatment for acute GVHD of the lower GI tract

Graft-versus-host disease (GVHD) is a major cause of morbidity and mortality following allogeneic hematopoietic transplantation. In experimental models, interleukin-22 promotes epithelial regeneration and induces innate antimicrobial molecules. We conducted a multicenter single-arm phase 2 study evaluating the safety and efficacy of a novel recombinant human interleukin-22 dimer, F-652, used in combination with systemic corticosteroids for treatment of newly diagnosed lower gastrointestinal acute GVHD. The most common adverse events were cytopenias and electrolyte abnormalities, and there were no dose-limiting toxicities. Out of 27 patients, 19 (70%; 80% confidence interval, 56%-79%) achieved a day-28 treatment response, meeting the prespecified primary endpoint. Responders exhibited a distinct fecal microbiota composition characterized by expansion of commensal anaerobes, which correlated with increased overall microbial α-diversity, suggesting improvement of GVHD-associated dysbiosis. This work demonstrates a potential approach for combining immunosuppression with tissue-supportive strategies to enhance recovery of damaged mucosa and promote microbial health in patients with gastrointestinal GVHD. This trial was registered at www.clinicaltrials.gov as NCT02406651.

Incidence and impact of new-onset postoperative arrhythmia after surgery of the lower gastrointestinal tract

Postoperative arrhythmias (PAs) are common events and have been widely investigated in cardiothoracic surgery. Within visceral surgery, a recent study revealed a significant occurrence of PA in esophageal resections. In contrast, PA in lower gastrointestinal surgery is rarely investigated and has been rudimentary described in the medical literature. The present work is a retrospective cohort study of 1171 patients who underwent surgery of lower gastrointestinal tract between 2012 and 2018. All included patients were treated and monitored in the intensive care unit (ICU) or intermediate care unit (IMC) after surgery. Follow-up, performed between January and May 2021, was obtained for the patients with PA investigating the possible persistence of PA and complications such as permanent arrhythmia or thromboembolic events after discharge. In total, n = 1171 patients (559 female, 612 male) without any history of prior arrhythmia were analyzed. Overall, PA occurred in n = 56 (4.8%) patients after surgery of the lower GI. The highest incidence of PA was seen in patients undergoing bowel surgery after mesenteric ischaemia (26.92%), followed by cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC; 16.67%). PA was significantly associated with higher age (72 years (IQR 63-78 years) vs. 64 years (IQR 55-73.5 years), p < 0.001) and longer length of stay in the ICU (median 15 days (IQR 5-25 days) vs. median 2 days (IQR 1-5 days), p < 0.001). PA was independently associated with organ failure (OR = 4.62, 95% CI 2.11-10.11, p < 0.001) and higher in-house mortality (OR = 3.37, 95% CI 1.23-9.28, p < 0.001). In median, PA occurred 66.5 h after surgery. In follow-up, 31% of all the patients with PA showed development of permanent arrhythmia. The incidence of PA after lower GI surgery is comparatively low. Its occurrence, however, seems to have severe implications since it is significantly associated with higher rates of organ failure and in-house mortality. Also, compared to the general population, the development of permanent arrhythmia is significantly higher in patients who developed new-onset PA.

Nutrition, defecation, and the lower gastrointestinal tract during critical illness

PURPOSE OF REVIEW

The goal of this report is to delineate the correlation between constipation as a manifestation of impaired gastrointestinal transit with adverse clinical outcomes, to identify risk factors, which predispose to this condition, and outline a management scheme for prophylactic treatment.

RECENT FINDINGS

Constipation is common in the ICU, affecting upwards of 60-85% of critically ill patients. As suggested by case series and observational studies, constipation may be an independent prognostic factor identifying patients with greater disease severity, higher likelihood of organ dysfunction, longer duration of mechanical ventilation, prolonged hospital length of stay, and possibly reduced survival. Treating constipation is a low priority for intensivists often relegated to the nursing service, and few ICUs have well designed protocols in place for a bowel regimen. Small randomized controlled trials show improvement in certain outcome parameters in response to a daily lactulose therapy; hospital length of stay, sequential organ failure assessment scores, and duration of mechanical ventilation. However, aggregating the data from these studies in two separate meta-analyses showed that the effect of a bowel regimen on these three endpoints were not statistically different.

SUMMARY

No causal relationship can be determined between constipation and adverse outcomes. Nonetheless, a clinical correlation seems to exist. Whether constipation is an epiphenomenon or simply a reflection of greater severity of critical illness, at some point it may contribute to worsening morbidity in the ICU. A graded prophylactic bowel regimen should help reverse impairment of the gastrointestinal transit and aid in reducing its deleterious impact on the hospital course of the critically ill patient.

Diagnostic utility of nasogastric tube aspiration and the ratio of blood urea nitrogen to creatinine for distinguishing upper and lower gastrointestinal tract bleeding

OBJECTIVES

The American College of Gastroenterology's 2016 clinical guidelines for treating lower gastrointestinal (GI) tract bleeding recommends evaluating of nasogastric tube aspiration and the ratio of blood urea nitrogen (BUN) to creatinine to differentiate upper from lower GI bleeds. However, the evidence base to support recommending these 2 diagnostic variables is low. This study aimed to evaluate the diagnostic utility of nasogastric tube aspiration and the BUN-to-creatinine ratio for distinguishing between upper and lower GI bleeding.

MATERIAL AND METHODS

We conducted a systematic review of the literature to find studies reporting the diagnostic precision of the BUN-to-creatinine ratio and nasogastric aspiration in patients with GI bleeding without hematemesis.

RESULTS

The sensitivity of both methods is low for detecting upper GI bleeding. Both blood in the aspirate and an elevated BUN-to-creatinine ratio significantly increase the probability of finding an upper GI source. The positive likelihood ratio varies from positive 2 to 11. However, the sensitivity of both tests for a diagnosis of upper GI bleeding is very low (negative likelihood ratio of 0.6).

CONCLUSION

A negative result on either of the 2 diagnostic tests provides little useful information and does not firmly rule out an upper GI bleed. Nasogastric tube aspiration cannot be recommended for distinguishing between upper and lower GI bleeding. If the diagnosis is in doubt, endoscopic exploration of the upper GI tract is necessary.

[Anesthetic Management of Laparoscopic Lower Gastrointestinal Tract Surgery]

This article reviews anesthetic management of lapa- roscopic lower gastrointestinal tract surgery. The recommended anesthetic method is general anesthesia, and tracheal intubation is an appropriate airway control method. It is important to understand hemodynamics and respiratory changes with pneumoperitoneum and Trendelenburg position during operation, especially in a patient with compromised cardiopulmonary functions. It is necessary to consider postoperative analge- sic method. An'enhanced recovery after surgery program may be useful to laparoscopic lower gastrointestinal tract surgery.

Localization and definitive control of lower gastrointestinal bleeding with angiography and embolization

Angiography has long been a mainstay of lower gastrointestinal bleeding localization. More recently, angioembolism has been used therapeutically for bleeding control, but there are limited data on its efficacy. This study was designed to evaluate the efficacy of angiography and embolization for localizing and treating lower gastrointestinal bleeding as well evaluate the occurrence of bowel ischemia after embolization. This study is a retrospective descriptive review of all patients undergoing mesenteric angiography at a tertiary hospital over an eight-year period. Clinical data were recorded including patient demographics, causes of bleeding, procedures, and outcomes. Patients were excluded if the cause of bleeding was upper gastrointestinal bleeding or the medical record was missing data. Localization and definitive control of bleeding was the primary end point. One hundred fifty-nine angiograms were performed on 152 patients. Mean age was 72 years. Angiographic localization was successful in 23.7 per cent of patients. Although embolization after angiographic localization achieved definitive control of bleeding in 50 per cent of patients, the success rate was only 8.6 per cent of all patients who had angiography. One patient developed postembolization ischemia requiring laparotomy. Angiographic localization of lower gastrointestinal bleeding is successful in only 23.7 per cent of patients. Definitive hemostasis through embolization was successful in only 8.6 per cent of patients who underwent angiography for lower gastrointestinal bleeding.

Lower gastrointestinal disorders in patients with irritable bowel syndrome

Irritable bowel syndrome (IBS) is a functional disorder of the gastrointestinal system characterized by abdominal pain related to bowel emptying, defecation impairment and abdominal distention. The aim of the study was to objectify lower gastrointestinal system disturbances in IBS patients. Thirty IBS patients and 30 healthy subjects were included in the study. IBS patients were divided into two subgroups: IBS with predominant diarrhea (IBSd) and IBS with predominant constipation (IBSc). All study subjects underwent physical examination (including digitorectal examination), standard laboratory testing and anorectal manometry. Endoscopy was performed only in group of IBS patients. A statistically significant difference was recorded in most manometric parameters between healthy subjects and IBS patients, which was even more pronounced in IBSd patients. Study results showed that the intestinal motility disorder underlying IBS could be objectified by use of anorectal manometry.

Management of lower gastrointestinal tract bleeding

Acute bleeding from the colon and rectum is less frequent and less dramatic than haemorrhage from the upper gastrointestinal tract. In most cases, bleeding from the colon and rectum is self-limiting and requires no specific therapy. Diverticula and angiectasias are the most frequent sources of bleeding. Malignancy, colitis (inflammatory bowel disease, non-steroidal anti-inflammatory drugs, and infectious colitis), ischaemia, anorectal disorders, postpolypectomy bleeding, and HIV-related problems are less frequent causes. The recurrence rate, especially in diverticular bleeding, is high. Resuscitation and haemodynamic stabilisation of the patient is the first step in the management of colonic bleeding. Urgent colonoscopy is the method of choice for diagnosis and therapy. By analogy with peptic ulcer bleeding, risk stratification using stigmata of haemorrhage is gaining more importance. Modern endoscopic techniques such as injection therapy, thermocoagulation and mechanical devices seem to be effective in achieving haemostasis and avoiding precarious surgery. Angiography and nuclear scintigraphy are reserved for those patients in whom colonoscopy is not possible or has repeatedly failed to localise the bleeding site.

Limited efficacy of gastrointestinal decontamination in severe slow-release carbamazepine overdose

OBJECTIVE

To report the limited efficacy of both multiple doses of activated charcoal (MDAC) and whole bowel irrigation (WBI) in a patient with severe overdose of slow-release carbamazepine.

CASE SUMMARY

A 25-year-old man was admitted in a comatose state with seizures after a suicide attempt with slow-release carbamazepine. Serum carbamazepine concentration on admission (16 h postingestion) was 52.08 microg/mL. The patient was mechanically ventilated and treated with MDAC and a 4 hour charcoal hemoperfusion. Carbamazepine concentration at the end of hemoperfusion was 27.16 microg/mL. Despite continuous treatment with MDAC, a rebound in carbamazepine concentration to 36 microg/mL was observed 32 hours after hemoperfusion (58 h postingestion). WBI was performed over a 10 hour period. The carbamazepine concentration continued to increase to 38.55 microg/mL and seizures recurred. After WBI was performed, MDAC was reinstituted; 33 hours later (102 h postingestion), the carbamazepine concentration began to decline. The hospitalization course was complicated by pneumonia, which necessitated continuation of mechanical ventilation and administration of antibiotics. The patient recovered completely and was discharged without sequelae 15 days after admission.

DISCUSSION

Serum carbamazepine concentration and toxicity were effectively reduced by hemoperfusion. The role of MDAC coadministered during hemoperfusion cannot be ruled out. However, a rebound in carbamazepine concentration with recurrent seizures was observed despite MDAC and WBI. The most likely explanation for this rebound (65 h postingestion, 39 h posthemoperfusion) is prolonged absorption, possibly from a pharmacobezoar. Redistribution cannot be excluded, but this is not supported by the concentration-time course and previous reports.

CONCLUSIONS

Both MDAC and WBI may be ineffective in reducing absorption and enhancing elimination in overdose of slow-release carbamazepine. Repeated hemoperfusion or other elimination enhancement techniques should be considered when the clinical and toxicokinetic course suggests the presence of a refractory pharmacobezoar.

Lower gastrointestinal bleeding

Lower gastrointestinal (GI) hemorrhage is a significant cause of morbidity and mortality, particularly in elderly patients. Lower endoscopic evaluation is established as the diagnostic procedure of choice in the setting of acute lower GI hemorrhage.

Systematic review: the lower gastrointestinal adverse effects of non-steroidal anti-inflammatory drugs

BACKGROUND

Lower gastrointestinal effects of non-steroidal anti-inflammatory drugs (NSAIDs) are much more poorly characterized than upper gastrointestinal effects.

AIM

To determine if NSAIDs increase lower gastrointestinal adverse effects and if the risk with non-selective NSAIDs is greater than with cyclooxygenase-2-selective inhibitors (coxibs).

METHODS

Computerized databases were searched to identify studies of NSAID use reporting on lower gastrointestinal integrity (e.g. permeability), visualization (e.g. erosions, ulcers) and clinical events.

RESULTS

Designs in 47 studies were randomized (18), case-control (14), cohort (eight) and before-after (seven). Non-selective-NSAIDs had significantly more adverse effects vs. no NSAIDs in 20 of 22 lower gastrointestinal integrity studies, five of seven visualization studies, seven of 11 bleeding studies (OR: 1.9-18.4 in case-control studies), two of two perforation studies (OR: 2.5-8.1) and five of seven diverticular disease studies (OR: 1.5-11.2). Coxibs had significantly less effect vs. non-selective-NSAIDs in three of four integrity studies, one endoscopic study (RR mucosal breaks: 0.3), and two randomized studies (RR lower gastrointestinal clinical events: 0.5; haematochezia: 0.4).

CONCLUSIONS

An increase in lower gastrointestinal injury and clinical events with non-selective-NSAIDs appears relatively consistent across the heterogeneous collection of trials. Coxibs are associated with lower rates of lower gastrointestinal injury than non-selective-NSAIDs. More high-quality trials are warranted to more precisely estimate the effects of non-selective-NSAIDs and coxibs on the lower gastrointestinal tract.

Validation of a clinical prediction rule for severe acute lower intestinal bleeding

OBJECTIVES

Acute lower intestinal bleeding is a heterogeneous disorder and identification of high-risk patients is challenging. We previously retrospectively identified predictors of severity in patients with acute lower intestinal bleeding. The aim of this study was to prospectively validate a clinical prediction rule for severe acute lower intestinal bleeding.

METHODS

This was a prospective, observational cohort study of consecutive patients admitted to an academic, tertiary care or a community-based teaching hospital for management of acute lower intestinal bleeding. Data were collected on seven previously identified predictors of severe bleeding: heart rate > or = 100/min, systolic blood pressure < or = 115 mmHg, syncope, nontender abdominal exam, rectal bleeding in the first 4 h of evaluation, aspirin use, and >2 comorbid conditions. Severe bleeding was defined as transfusion of > or =2 units of red blood cells, and/or a decrease in hematocrit of > or =20% in the first 24 h, and/or recurrent rectal bleeding after 24 h of stability (accompanied by a further decrease in hematocrit of > or =20%, and/or additional blood transfusions, and/or readmission for acute lower intestinal bleeding within 1 wk of discharge). Patients were stratified into 3 risk groups according to the previously developed prediction rule: low (no risk factors), moderate (1-3 risk factors), and high (>3 risk factors).

RESULTS

A total of 275 patients with acute lower intestinal bleeding were identified. The risk of severe bleeding in each risk category was similar in the validation and derivation cohorts (p values >0.05): low risk 6%versus 9%, moderate risk 43%versus 43%, and high risk 79%versus 84%. The area under the receiver operating characteristic curve was 0.754 for the validation cohort and 0.761 for the derivation cohort. The magnitude of the risk score was significantly correlated with major clinical outcomes including surgery, death, blood transfusions, and length of stay.

CONCLUSION

We have developed and prospectively validated a clinical prediction rule for acute severe lower intestinal bleeding. This prediction rule could improve the triage of patients to appropriate levels of care and interventions, and guide a more standardized approach to acute lower intestinal bleeding.

Acute lower gastrointestinal hemorrhages in geriatric patients

Age is a risk factor in acute lower gastrointestinal hemorrhages (LGIH). The objectives here were to analyze: (1) diagnostic and therapeutic handling, (2) related morbidity and mortality, (3) the indications for surgery, and (4) the evolution of acute LGIH in patients > or =80 years. Forty-three patients >80 years with acute LGIH were reviewed retrospectively. In 86% (n = 37) related comorbidities were found, in 9% (n = 4) there had been prior colorectal surgery, 19% (n = 8) were antiaggregated, and 7% (n = 3) were anticoagulated. One hundred thirty-two cases of acute LGIH in patients <80 years were used as a control group. Student's t test and the chi-square test were applied. On arrival at the emergency ward 11 cases (26%) had hemodynamic instability and 8 of these were stabilized using conservative measures. In 39 cases an endoscopy was performed, allowing for an etiological diagnosis in 59% (n = 23) of cases, above all in those carried out in an urgent or semiurgent way. The arteriography permitted an etiological diagnosis in two of the four cases in which it was carried out. In seven patients (16%) urgent surgery was indicated: three were hemorrhoidectomies, three were subtotal colectomies, and one was a resection of the small intestine. The morbidity rate was 10% (n = 4) in the patients who were not treated and 14% (n = 1) in those treated, with a mortality rate of 8% (n = 3) and 14% (n = 1), respectively. The rate of relapse of bleeding after discharge from hospital was 42% (n = 18), with nine of these needing to be readmitted into hospital. In comparison with the control group, they present a different bleeding etiology (diverticulosis as opposed to the benign anal-rectal and small intestinal pathology in the younger population; P = 0.017), surgery is indicated with less frequency (9 versus 33%; P = 0.007), and there is a higher relapse rate (42 versus 26%; P = 0.045). Acute LGIH in geriatric patients relents in most cases with the use of conservative measures, although there is a high percentage of related morbidity and mortality, and of relapse of bleeding.

Predictors of utilization of early colonoscopy vs. radiography for severe lower intestinal bleeding

BACKGROUND

The management of acute lower intestinal bleeding is not standardized. This study assessed factors associated with early (within 24 hours of presentation) colonoscopy vs. radiographic evaluation of patients with severe acute lower intestinal bleeding in routine practice.

METHODS

A cohort of 252 patients admitted with acute lower intestinal bleeding to a teaching hospital (August 1996 to June 1999) was studied retrospectively. Severe bleeding was defined as transfusion of two units of packed red blood cells and/or a greater than 20% decrease in hematocrit within 24 hours of presentation. If both colonoscopy and radiography were performed, the initial procedure was analyzed. Multivariable regression was used to identify independent factors related to each of the two initial interventions.

RESULTS

A total of 118 patients met criteria for severe bleeding; 33 (28%) underwent an initial, early colonoscopy and 20 (17%) underwent an initial, early radiographic procedure (17 radionuclide scintigraphy, 3 angiography). Independent factors related to early colonoscopy were post-polypectomy bleeding (OR 6.3: 95% CI[1.4, 28.0]), admission on a weekday (OR 3.0: 95% CI[1.0, 8.6]), and admission late in the day (OR 2.7: 95% CI[1.0, 7.0]). Independent factors related to early radiography were tachycardia (OR 5.1: 95% CI[1.7, 14.9]), syncope (OR 3.8: 95% CI[1.1, 13.2]) and bleeding during the first 4 hours after admission (OR 3.1: 95% CI[1.0, 9.0]). Colonoscopy was associated with shorter hospital stay (p=0.025), increased diagnostic yield (p=0.005), and fewer red blood cell transfusions (p=0.024). Rates of therapeutic intervention, surgery, and death did not differ significantly between the two strategies.

CONCLUSIONS

Logistical factors and the likelihood of a localized source of bleeding influence the performance of early colonoscopy for the evaluation of acute lower intestinal bleeding, whereas patients with clinical indicators of severe bleeding often undergo radiographic procedures. Because early colonoscopy may improve outcomes, further studies are needed to compare available strategies and to standardize the management of acute lower intestinal bleeding.

Microcatheter embolization of lower gastrointestinal hemorrhage: an old idea whose time has come

Early attempts of using embolization for lower gastrointestinal hemorrhage were fraught with complications, most notably ischemic colitis or bowel infarction. Embolotherapy was eventually abandoned in favor of catheter-directed vasoconstriction (i.e., vasopressin infusion). This latter therapy is time and labor intensive. With the advent of microcatheter technology, superselective embolization emerged and is rapidly becoming the endovascular therapy of choice for patients with severe lower gastrointestinal hemorrhage refractory to medical management. Numerous studies on the subject have consistently reported high clinical success with low ischemic complications. This article will review the current status of co-axial microcatheter embolization with an emphasis on the technical aspects of the procedure.