Reusable biopsy forceps: a prospective evaluation of cleaning, function, adequacy of tissue specimen, and durability.

BACKGROUND: Recent studies have indicated that reusable biopsy forceps remain contaminated after reprocessing and can only be used a mean of 12 to 25 times without malfunction. Because this contradicts traditional endoscopic practice, our study investigated the ability to sterilize a type of commercially available biopsy forceps and prospectively evaluated their function in vivo until malfunction and/or breakage. METHODS: Thirty reusable biopsy forceps were studied, 15 of which were contaminated for 5 trials each with 10(6) Bacillus stearothermophilus, and 15 of which were prospectively evaluated clinically over an 18-month period (9/98-3/00). Contaminated forceps were reprocessed by using a standard protocol and placed in a sterile bag containing soy broth. The latter was passed through a 0.2 micron filter and was subsequently cultured. In vivo data included biopsy site, size, adequacy, problems obtaining a biopsy specimen, and reasons for ultimate forceps failure. RESULTS: After contamination, all biopsy forceps yielded a heavy growth of B stearothermophilus. No forceps, including 5 that were piecemeal dismantled with a wire cutter, had residual bacteria after reprocessing. In the in vivo study, 1507 biopsy sessions were undertaken in 1339 procedures. Forceps were categorized as new or like-new in 1259 of 1339 (94%) procedures, some loss of function but usable in 72 of 1339 (5.4%), and inadequate function or broken at use in 8 of 1339 (0.6%). Histologically, 1501 specimen sets were adequate (99.6%) and mean specimen size was 2.7 +/- 0.1 mm. Mechanical problems were noted in only 38 of 1507 (3%) sessions to include such things as sticky forceps, and the mean number of uses to malfunction or breakage was 91 +/- 15 (SEM) (range 19-132). CONCLUSIONS: This reusable biopsy forceps can be sterilized and used a mean of 91 times with adequate tissue sampling. Mechanical problems were minor to time of breakage. Contingent on acquisition and reprocessing costs as well as the number of procedures performed, this reusable forceps has the potential for significant cost savings.

A cost-effective approach to the patient with peptic ulcer bleeding.

The average hospital cost to manage patients hospitalized at Virginia Mason Hospital who bleed from a peptic ulcer is approximately $5000 per patient in our series of 30 patients. Because there are 150,000 admissions per year in the United States for peptic ulcer bleeding, the total hospital cost can be estimated to be $750 million. The actual cost may be higher because our 30 patients had minimal complications and were discharged on average in less than 4 days. The majority of hospital cost is incurred by the intensive care unit or the hospital nursing floor. There is a close to linear relation between the length of stay and the total hospital cost. Upper gastrointestinal endoscopy is a major advance in the treatment of peptic ulcer bleeding. It can provide significant cost savings by identifying some patients with bleeding peptic ulcers who have clean bases on endoscopy who are then eligible for prompt discharge from the hospital. In addition, endoscopic thermal therapy (with multipolar electrocautery or heater probe) and injection therapy cost less than $50 in incremental cost and can reduce further bleeding by 43%, reduce the need for urgent surgery by 63%, and reduce the mortality rate by 60%. Some patients still require urgent surgical intervention, which is substantially more costly than endoscopic hemostasis but is highly effective. Preliminary studies show promise in predicting further bleeding, with clinical scoring systems such as the Baylor Bleeding Score and with the use of Doppler ultrasonography. Better prediction of further bleeding should guide the choice of durable hemostasis early in the hospitalization. Additional studies should clarify the role of NSAID avoidance and H. pylori eradication in the long-term prevention of recurrent peptic ulcer bleeding.

Endoscopic treatment of pancreatic ascites.

Pancreatic ascites, etiologically related to a leaking pseudocyst or ductal disruption, has been treated medically with hyperalimentation, somatostatin analog, and large-volume paracentesis. Surgery is ultimately required in more than 50% of such patients. Mortality figures in patients with pancreatic ascites approximate 15% to 25% with either treatment modality. We describe 4 patients who were found to have ductal disruptions in conjunction with pancreatic ascites who responded to transpapillary pancreatic duct endoprosthesis placement. There has been no recurrence of ascites in these patients at a mean follow-up of 12 months following stent-retrieval. Further evaluation of endoscopic therapy for pancreatic ascites appears warranted.

Experimental use of high-frequency ultrasound to image bowel wall after porcine intestinal transplantation.

A means to monitor intestinal allografts will be crucial for the future success of small bowel transplantation. We have previously demonstrated the ability of high-frequency ultrasound (US) to diagnose porcine intestinal ischemia in vitro. The aim of this study was to compare the histologic appearance of normal porcine small bowel versus bowel undergoing acute rejection, using 8.5-MHz US images. We allowed porcine heterotopic small bowel allograft transplants to reject and then removed, at scheduled intervals from postoperative day 0 to 12, specimens of both the transplanted bowel and the native bowel. We examined the tissues in vitro with an 8.5-MHz linear array US system then studied them histologically. Histologically, the earliest changes of rejection occurred at days 4 to 5, with mild submucosal edema, endotheliitis, and vasculitis affecting the small vessels; the mucosa remained normal. By days 7 to 8, the submucosal endotheliitis became more prominent, with focal thrombosed small vessels; the mucosa now appeared abnormal with flattened villi, erosions, and necrosis. By days 10 to 12, marked submucosal edema, vasculitis, endotheliitis, and necrotic mucosa were present. Ultrasonically, normal intestinal wall has five wall layers, corresponding to mucosa, submucosa, muscularis propria, and subserosal fat. The US criteria for abnormality were loss of folds, decreased numbers of echo layers, discontinuity of layers, and a homogeneous appearance. Using these US criteria, blinded observers differentiated normal from abnormal bowel wall after transplantation with a sensitivity of 84% and a specificity of 81%. Most of the errors occurred with the day 4 and 5 specimens, which appeared nearly normal on US.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of a 20-MHz ultrasound transducer used in diagnosing porcine small bowl ischemia.

The authors have previously demonstrated the ability of an 8.5-MHz linear array to detect moderate or severe intestinal ischemia in a porcine model. This study compares the ability of the 8.5-MHz linear array with a prototype miniature 20-MHz ultrasound (US) imaging probe in detecting small bowel ischemia. Five piglets were studied in which vascular clamps were applied to isolated jejunal pedicles, then released sequentially at hourly intervals to induce ischemia from 0 to 6 hours. After 24 hours of reperfusion, the tissue was removed and examined with both the 8.5-MHz linear array and the 20-MHz probe. A histologic examination also was done. The acoustical criteria used for interpretation were presence or absence of folds, number of echo layers, relative thickness of layers and homogeneity and continuity of layers. The 8.5-MHz system predicted the duration of ischemia with a kappa value of 0.66 +/- 0.03, whereas the 20-MHz system had a kappa value of 0.49 +/- 0.03. Both systems were able to distinguish normal or mild ischemia from moderate or severe ischemia with sensitivity and specificity rates of at least 94%. Both 8.5- and 20-MHz US systems detected intestinal ischemia in vitro. Further studies are indicated to determine the ideal frequency and design for a US system that can be used clinically.

Use of ultrasound to detect intestinal wall ischemia in piglets.

To evaluate the use of ultrasound (US) to detect intestinal wall ischemia, we isolated segments of jejunum on single vascular pedicles in five piglets. We sequentially clamped these segments in intervals of 0 to 6 h, reperfused them for 24 h, and then examined them in vitro histologically and with an 8.5 MHz US scan. All segments were grossly viable except those with 6 h of ischemia. Histologically, mild submucosal edema developed after 1 to 2 h of ischemia; after 3 to 4 h, mucosal necrosis, loss of folds, worsening submucosal edema, and prominent neutrophilic infiltration occurred; after 5 to 6 h, severe mucosal necrosis with hemorrhage and submucosal edema was present. Ultrasonically, we saw five wall layers in the control group corresponding to mucosa, submucosa, muscularis propria, and subserosal fat. After mild (1 to 2 h) ischemia, all layers were present except for a discontinuity in layer 3. After moderate (3 to 4 h) ischemia, the five layers persisted but with a markedly thickened submucosal layer, reduced echogenicity, and flattened mucosal folds. With severe (5 to 6 h) ischemia, we observed a loss of all normal layers with no discernible architecture. Using these US criteria, blinded observers were able to differentiate normal/mild from moderate/severe ischemia with a sensitivity and specificity of 100%. These data suggest that US can differentiate, in vitro, normal from moderate and severe degrees of intestinal wall ischemia that correlates well with the histological appearance. Endoscopic US or surgically implantable US probes can potentially help diagnose clinical intestinal wall ischemia.

Experimental evaluation of an endoscopic ultrasound probe: in vitro and in vivo canine studies.

We developed an endoscopic echo probe that can be passed via the biopsy channel of a flexible fiberoptic or video endoscope with a 3.5-mm channel. The probe moves along the gastrointestinal wall under direct endoscopic vision. The translational scanning action is sensed by a position potentiometer and combines with the ultrasonic B-mode echoes to produce a cross-sectional image of the wall. The system uses an ultrasound frequency of 20 MHz to produce high-resolution images. The device was used to image canine gastrointestinal tissue in vitro and in vivo during endoscopy. Ultrasound images of the gut wall correlate with histologic structure. This probe overcomes some of the problems associated with the combined ultrasound endoscopes now in use. Use of the probe with video endoscopy allows the endoscopic and ultrasound images to be displayed side by side, simplifying coordination of application of the two techniques.

Misoprostol reduces gastroduodenal injury from one week of aspirin: an endoscopic study.

Misoprostol is a synthetic prostaglandin E1 analogue that inhibits gastric acid production and may augment mucosal defense. A double-blind trial examined the effect of misoprostol on the endoscopic appearance of gastroduodenum at the end of 1 wk of aspirin ingestion. One hundred thirty healthy subjects were randomized to take either 50, 100, or 200 micrograms of misoprostol, or placebo along with 975 mg of aspirin four times daily. Fewer subjects developed acute endoscopic gastric ulcers in the group taking any dose of misoprostol compared with the placebo group (1% vs. 43%). No subject taking the 100- or 200-micrograms dose of misoprostol developed an acute endoscopic duodenal ulcer compared with 13% of subjects taking placebo (p less than 0.05). Significantly fewer subjects developed gastric erosions and significantly fewer subjects developed duodenal erosions in each of the three groups taking misoprostol compared with the placebo group (p less than 0.01). There were fewer subjects with a gastric erosion (p less than 0.05) and fewer subjects with a duodenal erosion (p less than 0.05) in the group taking the 200-micrograms dose compared with the group taking the 50-micrograms dose of misoprostol. Gastrointestinal symptoms causing a modification in usual activities were infrequent but there was significantly more diarrhea in the 200-micrograms misoprostol group. There was no correlation between endoscopic scores and symptoms in any group. We conclude that misoprostol can protect the normal gastroduodenum from acute ulceration and reduce the chance of erosion after 1 wk of aspirin ingestion.