The levels of recommendation (1-3) and classes of evidence (I-III) are defined at the end of the "Major Recommendations" field.
Diagnosis
- All patients being evaluated for small bowel obstruction (SBO) should have plain films due to the fact that plain films are as sensitive as computed tomography (CT) to differentiate obstruction vs. non-obstruction. Level III
- All patients with inconclusive plain films for complete or high grade SBO should have a CT as CT scan gives incremental information over plain films in regard to differentiating grade of obstruction and etiology of small bowel obstruction leading to changes in planned management. Level I
- Multiple signs on CT suggesting strangulation should suggest a low threshold for operative intervention. Level II
- Magnetic resonance imaging (MRI) and ultrasound are an alternative to CT with similar sensitivity and identification of etiology, but have several logistical limitations. Level III
- There is a variety of literature that contrast studies should be considered in patients who fail to improve after 48 hours of conservative management as a normal contrast study can rule out operative small bowel obstruction. Level II
- Nonionic low osmolar weight contrast is an alternative to barium for contrast studies to evaluate for SBO for diagnostic purposes. Level I
Management
- Patients with plain film finding of small bowel obstruction and clinical markers (fever, leukocytosis, tachycardia, metabolic acidosis and continuous pain) or peritonitis on physical exam warrant exploration. Level I
- Patients without the above mentioned clinical picture, and a partial SBO or a complete SBO can undergo non-operative management safely; although, complete obstruction has a higher level of failure. Level I
- Patients without resolution of their SBO by day 3-5 of non-operative management should undergo water soluble study or surgery. Level III
- There is no significant difference with regard to the decompression achieved, the success of nonoperative treatment, or the morbidity rate after surgical intervention comparing long tube decompression with the use of nasogastric tubes. Level I
- Water soluble contrast (Gastrograffin) given in the setting of partial SBO can improve bowel function (time to bowel movement [BM]), decrease length of stay, and is both therapeutic and diagnostic. Level II
- In a highly selected group of patients the laparoscopic treatment of small bowel obstruction should be considered and leads to a shorter hospital length of stay. Level II
Definitions:
Classes of Evidence
Class I: Prospective, randomized, controlled trial (there were no Class I articles reviewed)
Class II: Clinical studies in which the data was collected prospectively, and retrospective analyses which were based on clearly reliable data. Types of studies so classified include: observational studies, cohort studies, prevalence studies, and case control studies.
Class III: Studies based on retrospectively collected data. Evidence used in this class includes clinical series, database or registry reviews, large series of case reviews, and expert opinion.
Levels of Recommendation
Level 1: This recommendation is convincingly justifiable based on the available scientific information alone. It is usually based on Class I data, however, strong Class II evidence may form the basis for a level 1 recommendation, especially if the issue does not lend itself to testing in a randomized format. Conversely, weak or contradictory Class I data may not be able to support a level 1 recommendation.
Level 2: This recommendation is reasonably justifiable by available scientific evidence and strongly supported by expert critical care opinion. It is usually supported by Class II data or a preponderance of Class III evidence.
Level 3: This recommendation is supported by available data but adequate scientific evidence is lacking. It is generally supported by Class III data. This type of recommendation is useful for educational purposes and in guiding future studies.