CLINICAL AND BIOMEDICAL PREDICTORS OF BOWEL ISCHEMIA IN PATIENTS WITH ACUTE INTESTINAL OBSTRUCTION

Abstract

Acute intestinal obstruction is a major surgical emergency that may progress to bowel ischemia, necrosis, perforation, sepsis, multiorgan dysfunction, and death. Early recognition of ischemic bowel remains challenging because clinical manifestations may be nonspecific and no individual laboratory or radiological parameter provides adequate diagnostic certainty. Recent evidence supports the use of integrated clinical, biomedical, and computed tomography (CT)-based assessment for identifying patients at increased risk of ischemia. This study aimed to examine clinical, biomedical, and CT-based predictors of bowel ischemia among patients presenting with acute intestinal obstruction in tertiary-care settings represented by Lahore and Islamabad, Pakistan. A hospital-based observational research framework was developed using a simulated dataset of 200 adult patients, including 120 patients representing Lahore and 80 representing Islamabad. The primary outcome was bowel ischemia. Clinical variables included symptom duration, tachycardia, hypotension, abdominal tenderness, and rebound tenderness. Biomedical variables included white blood cell (WBC) count, neutrophil-to-lymphocyte ratio (NLR), serum lactate, C-reactive protein (CRP), lactate dehydrogenase (LDH), and serum sodium. CT variables included free intraperitoneal fluid, reduced bowel-wall enhancement, and closed-loop obstruction. Descriptive statistics, chi-square tests, independent-samples comparisons, multivariable logistic regression, and receiver operating characteristic (ROC) analysis were applied. Of the 200 simulated patients, 38 (19.0%) were classified as having bowel ischemia. Ischemia was associated with tachycardia, prolonged symptom duration, rebound tenderness, elevated WBC, NLR, lactate, CRP, and LDH, as well as free intraperitoneal fluid, reduced bowel-wall enhancement, and closed-loop obstruction. Multivariable logistic regression identified tachycardia (adjusted odds ratio [AOR] = 4.70, 95% CI [2.01, 10.98]), rebound tenderness (AOR = 4.55, 95% CI [2.03, 10.19]), and reduced bowel-wall enhancement (AOR = 3.82, 95% CI [1.72, 8.48]) as the strongest independent predictors. The combined multimodal model demonstrated the highest simulated discriminatory performance (AUC = .92). The findings support a multimodal approach integrating clinical examination, biomedical markers, and CT characteristics for early risk assessment of bowel ischemia in acute intestinal obstruction. Tachycardia, rebound tenderness, and reduced bowel-wall enhancement were the strongest independent predictors in the simulated cohort. However, because the dataset is synthetic, the findings should be considered hypothesis-generating. Prospective studies using real patient data from Lahore and Islamabad are required before the proposed predictors or thresholds can be used clinically.