The accuracy of polyp size estimations in clinical studies is not known. This study was designed to evaluate how well endoscopists can estimate the size of objects at endoscopy. Observations were made by six attending gastroenterologists, six gastroenterology fellows, and seven untrained medical residents. Ball bearings ranging in size from 3 mm to 19 mm were randomly inserted into a latex colon model, and size was estimated while being viewed with a video colonoscope with and without the aid of an open biopsy forceps. Estimated size correlated well to actual size (R ranged from 0.78 to 0.93), although the mean estimates were consistently lower (13% to 29%) than the actual size for all groups, with and without forceps. The use of forceps did not improve the estimates. Exactly correct estimates occurred in 8%; errors of as much as 110% were recorded. The 12 mm bearing was estimated to be less than 10 mm half of the time. We conclude that endoscopists frequently underestimate the size of objects viewed at the time of endoscopy. There was no difference in the performance of experienced gastroenterologists, fellows in training, or untrained residents. This study indicates that better methods of training and for determining size are needed. Research that depends on endoscopic estimates of polyp size may be biased.

Analysis of Variance↗

PubMedDate not supplied

Enteroscopy in patients with gastrointestinal bleeding of obscure origin.

Approximately 5% of all patients with gastrointestinal hemorrhage will not have a bleeding site found after standard evaluation with upper endoscopy and colonoscopy. The source of bleeding in these patients is often the small intestine. In the past 2 decades, our ability to examine the small bowel endoscopically has been enhanced by the use of intraoperative enteroscopy and the development of push and sonde enteroscopes. In a stepwise evaluation of the patient with obscure gastrointestinal bleeding using enteroscopy, the identification of a bleeding source has been reported in 70-100% of patients, usually leading to palliative, if not definitive, therapy. In this review we discuss the indications, methods and yields of each of these procedures, and propose a diagnostic algorithm with which to approach these patients.

Algorithms↗

PubMedDate not supplied

Alteration of in vivo zoxazolamine metabolism by carbon monoxide in normal and polycyclic hydrocarbon-treated immature male rats.

The effect of carbon monoxide exposure on the in vivo metabolism of zoxazolamine in normal (corn oil-treated) and 3,4-benzpyrene- and 3-methylcholanthrene-treated, immature, male rats was examined. Pre-exposure of the animals for 90 min followed by determination of the duration of drug action while the animals were maintained in the experimental atmosphere resulted in a qualitative difference in response between normal and polycyclic hydrocarbon-treated animals over the concentration range of 150-450 ppm CO. Corn oil-treated animals demonstrated a decreased duration of drug action when exposed to CO, indicating an increase in the bioavailability of drug for metabolism which may be a result of an increase in liver perfusion rates. In contrast, polycyclic hydrocarbon-treated animals demonstrated an increased duration of drug action on exposure to CO. The qualitative difference in response to CO exposure in the two groups of animals may be due to differences in the sensitivity of cytochrome P-450 and cytochrome P-448 with respect to complexing with CO or to lowered intracellular PO2; or to differences in the dependency on blood flow of the rate of in vivo metabolism of zoxazolamine.

Animals↗