PubMed Health⌕ Search

Biomedical subjects

O W Cass

Publications and source records attributed to O W Cass.

At least 19 recordsLinked to original sources
PubMed2001

Dilation of high-grade pancreatic and biliary ductal strictures with small-caliber angioplasty balloons.

BACKGROUND: Pancreatic and bile duct strictures may be too stenotic to allow passage of conventional endoscopic dilators. METHODS: Four patients with strictures (3 pancreatic, 1 biliary) that could not be traversed with conventional endoscopic dilating devices, or in 1 case by a Soehendra stent extractor, underwent stricture dilation with a 3.3F peripheral angioplasty balloon to a maximum diameter of 6 mm. OBSERVATIONS: All strictures in the 4 patients were successfully traversed and dilated and stents were placed with resolution of the presenting clinical problem. CONCLUSIONS: Small-caliber angioplasty balloons are useful for dilation with subsequent stent placement of pancreatic and biliary strictures that are refractory to standard endoscopic approaches.

Adult↗
PubMed2001

A randomized, controlled trial of interactive, multimedia software for patient colonoscopy education.

The purpose of our study was to assess the effectiveness of computer-assisted instruction (CAI) in patients having colonoscopies. We conducted a randomized, controlled trial in large, multispecialty clinic. Eighty-six patients were referred for colonoscopies. The interventions were standard education versus standard education plus CAI, and the outcome measures were anxiety, comprehension, and satisfaction. Computer-assisted instruction had no effect on patients' anxiety. The group receiving CAI demonstrated better overall comprehension (p < 0.001). However, Comprehension of certain aspects of serious complications and appropriate postsedation behavior were unaffected by educational method. Patients in the CAI group were more likely to indicate satisfaction with the amount of information provided when compared with the standard education counterparts (p = 0.001). Overall satisfaction was unaffected by educational method. Computer-assisted instruction for colonoscopy provided better comprehension and greater satisfaction with the adequacy of education than standard education. Computer-assisted instruction helps physicians meet their educational responsibilities with no decrement to the interpersonal aspects of the patient-physician relationship.

Adult↗
PubMed2000

A randomized, controlled trial of transcutaneous carbon dioxide monitoring during ERCP.

BACKGROUND: Pulse oximetry, used to monitor oxygen saturation during endoscopy, does not directly measure hypoventilation. Study goals were to determine whether transcutaneous carbon dioxide (PtcCO(2)) monitoring during endoscopic retrograde cholangiopancreatography (ERCP) prevents severe hypoventilation and to assess the accuracy of clinical observation and pulse oximetry in detecting hypoventilation. METHODS: All patients received intensive clinical and electronic monitoring including pulse oximetry. Supplemental oxygen was administered for pulse oximetry < 90%. Patients were randomized to a treatment arm (group 1) where PtcCO(2) monitoring guided sedation or a control arm (group 2) where PtcCO(2) was recorded but unavailable for guiding sedation. RESULTS: Group 1 had significantly fewer episodes of severe carbon dioxide retention (rise in PtcCO(2) >/=40 mm Hg above baseline) than group 2 (0 of 199 versus 5 of 196, respectively, p = 0.03), as well a shorter mean duration of procedure discomfort (8.3% of procedure duration rated as "uncomfortable" versus 11.5%, p = 0.04). Correlations between clinical observation and objective measures of ventilation were poor: level of sedation versus PtcCO(2) (R = 0.3) or pulse oximetry (R = 0.06); slowest respiratory rate versus PtcCO(2) (R = 0.4) or pulse oximetry (R = -0.4). PtcCO(2) rises of greater than 20 mm Hg occurred without oxygen desaturation in 10.7% of patients receiving supplemental oxygen. CONCLUSIONS: Carbon dioxide retention during ERCP is not reliably detected by clinical observation or by pulse oximetry in patients receiving supplemental oxygen. The addition of PtcCO(2) monitoring prevents severe carbon dioxide retention more effectively than intensive clinical monitoring and pulse oximetry alone. The clinical relevancy of this observation needs to be determined in an appropriately designed outcome study.

Blood Gas Monitoring, Transcutaneous↗
PubMed1999

Insertion, efficacy, and removal of a nonendoscopically removable percutaneous endoscopic gastrostomy (PEG) tube.

BACKGROUND: Externally removable PEG tubes require an internal bumper that can collapse to a size that is small enough to allow for its removal through the abdominal wall by external traction. Adequate force must be maintained to avoid accidental dislodgement of the tube prior to its desired removal. METHODS: A nonendoscopically removable PEG (Inverta-PEG, Ross Products Division, Abbott Laboratories, Columbus, OH, USA) was evaluated in a nonmasked, prospective clinical study involving 131 patients enrolled by 25 physicians. The over-the-wire (Sacks-Vine) technique was used for all placements. After insertion, patients were followed weekly for 8 weeks. During week 9, the PEGs were removed percutaneously (nonendoscopically). Insertion, efficacy, and removal performance were evaluated. RESULTS: Complication rate during insertion was 1.5% and removal was 1.2%. Qualitatively, investigators rated ease of insertion and removal as very easy, easy, average, difficult, or very difficult. Investigators rated 98.5% of insertions as very easy, easy, or average; 95.4% of removals were rated as very easy, easy, or average. Some patients exited the study prematurely due to leakage around the stoma (2.3%) and inadvertent tube removal (5.3%). These complication rates were consistent with earlier reports of other PEG studies. CONCLUSIONS: These results demonstrate that Inverta-PEG is a safe and effective tube that can be removed nonendoscopically with ease in 95% of the cases.

Adult↗
PubMed1997

Group I: choosing the appropriate method of placement of an enteral feeding tube in the high-risk population.

The traditional nasogastric/nasoenteric feeding tube is the preferred access device for short-term feeding (< 30 days), with delivery into the stomach suggested unless aspiration or motility abnormalities are present. Preference for a long-term access device is operator- and facility-dependent. Endoscopic or fluoroscopic placement is preferred as first choices over laparoscopic placement because of considerations of cost, need for general anesthesia, and need for operating room time. Gastrostomy is preferred over intestinal placement for long-term access unless problems with aspiration or motility abnormalities exist.

Critical Illness↗
PubMed1995

Objective evaluation of competence: technical skills in gastrointestinal endoscopy.

Documentation of an individual trainee's competence in gastrointestinal endoscopy has relied on the opinion of supervisors. Recommendations about the minimum number of procedures required to attain technical competence has relied on expert opinion. Recently, objective data about procedural competence have been collected. These data suggest that the mean number of procedures required to approach technical competence is higher than that recommended by experts. The data can be used to give a more accurate and objective evaluation of each trainee, as well as to develop objective guidelines about the minimum number of procedures to be accomplished during training. In addition, objective grading systems can be applied to other surgical and nonsurgical procedures.

Clinical Competence↗
PubMed1993

Objective evaluation of endoscopy skills during training.

OBJECTIVE: To evaluate the number of supervised gastrointestinal endoscopic procedures required to achieve initial competency using a simple objective grading system. DESIGN: Prospective, cross-sectional study. SETTING: A gastroenterology and surgical training program at a large, university-affiliated county hospital. PARTICIPANTS: Seven gastroenterology fellows and five fourth-year surgery residents. INTERVENTIONS: Trainees were graded postprocedure using a microcomputer program. Grading criteria for esophagogastroduodenoscopy included entering the esophagus (esophageal intubation), traversing the pylorus into the duodenum, and recognizing whether the upper gastrointestinal tract was abnormal. Criteria for colonoscopy were traversing the splenic flexure, intubating the cecum, and recognizing whether the colon was abnormal. RESULTS: When presented with a case mix representative of practice, esophageal intubation did not reach 90% until more than 100 procedures had been done. Cecal intubation remained at only 84% after 100 procedures. CONCLUSIONS: More than 100 supervised upper gastrointestinal endoscopies or colonoscopies are necessary to achieve technical competence in gastrointestinal endoscopy.

Clinical Competence↗
PubMed1993

Carbon dioxide retention and oxygen desaturation during gastrointestinal endoscopy.

BACKGROUND: Pulse oximetry measures arterial oxygen saturation (SpO2), not hypoventilation, which is directly reflected by increases in carbon dioxide tension. METHODS: In the present study, transcutaneous carbon dioxide tension (PtcCO2) and SpO2 were measured during 101 endoscopic procedures selected for long duration or comorbid illnesses, and relationships between hypercapnia and hypoxemia were evaluated. Nasal oxygen was administered only for sustained desaturation (SpO2 < 90%). RESULTS: Mean peak increase in PtcCO2 was significantly higher in patients requiring oxygen for sustained desaturation (16.3 mm Hg; range, 4-52) than in patients breathing room air who had transient or no desaturation (10.2 mm Hg [range, 3-19] and 5.1 mm Hg [range, 0-15]). If nasal oxygen corrected desaturation, even transient recurrence of desaturation indicated worsening CO2 retention, which preceded respiratory arrest in one patient. Independent predictors of hypercapnia were fentanyl and midazolam doses, oxygen requirement, and dementia. CONCLUSIONS: Severe hypoventilation may occur during endoscopy, undetected by clinical observation or pulse oximetry, but only in sedated patients who require supplemental oxygen to maintain SpO2 above 90%. After oxygen supplementation corrects desaturation, recurrence of desaturation implies severe hypoventilation and warrants limitation of further sedation.

Adult↗
PubMed1986

Modern imaging and endoscopic biopsy techniques in Egyptian mummies.

Egyptian mummies have been popular subjects of radiographic investigation since 1896. Computed tomography (CT) and magnetic resonance imaging (MRI) have recently been added to the growing list of modern techniques used to study these relics. The Minnesota Mummy Project was organized to examine four well preserved Egyptian mummies dating from the XVIIIth (1575-1308 B.C.) and XXVth (715-663 B.C.) Dynasties. Plain radiographs and CT scans were obtained on all specimens. One individual was selected for additional endoscopic and microscopic correlation with CT findings in the thoracic cavity. The collapsed heart was identified by CT. A percutaneous biopsy of the heart was then performed with a flexible fiberoptic endoscope, passed through a small hole drilled into the chest wall. Microscopy of prepared ventricular specimens revealed striated muscle fibers consistent with myocardium. These results emphasize the utility of CT as a noninvasive paleoradiologic tool. Another mummy was examined by MRI to search for minute quantities of residual moisture possibly trapped within the desiccated tissues. Only a free-induction-decay signal could be obtained, but this was insufficient to generate an image. Thus, it appears that present MRI is not suitable for the paleopathologic investigation of dehydrated structures.

Biopsy↗
PubMed1980

Competitive inhibition of side chain oxidation of 3 alpha, 7 alpha-dihydroxy-5 beta-cholestan-26-oic acid by 3 alpha, 7 alpha, 12 alpha-trihydroxy-5 beta-cholestan-26-oic acid in the hamster.

3 alpha,7 alpha-dihydroxy-5 beta-cholestan-26-oic acid (DHCA) and 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestan-26-oic acid (THCA) are metabolized into chenodeoxycholic acid and cholic acid, respectively, through oxidation and cleavage of the terminal three carbons of the side chain. The present study was designed to determine if the same or different side chain oxidation systems are used by these compounds in the bile fistula hamster model. Although a single injection of [3H]THCA is nearly completely metabolized into cholic acid, only about 50% is converted into cholic acid when THCA is infused at a rate of 0.083 mumol/min. The remainder is excreted in the bile unchanged indicating saturation of the side chain oxidation system. Fifty-nine +/- 1.1% (+/- 1SEM) of a single injection of [3H]DHCA is metabolized into chenodeoxycholic acid in bile fistula hamsters infused with either saline or cholic acid at a rate of 0.083 mumol/min. The remainder was excreted as several other metabolic products including cholic acid. However, when [3H]DHCA was administered during an 0.083 mumol/min infusion of THCA, only 39.0 +/- 4.5% of the radioactivity in bile was identified as chenodeoxycholic acid. Thus, this study indicates that DHCA and THCA share at least one of the enzymes involved in side chain oxidation.

Animals↗
PubMed1975

Metabolism of lithocholate in healthy man. II. Enterohepatic circulation.

Studies were carried out in healthy subjects to characterize the enterohepatic circulation of lithocholate and its metabolites. When mixed with bile and infused into the jejunum, radiolabeled lithocholylglycine was absorbed more rapidly and more efficiently than sulfolithocholylglycine, based on recovery from bile. When these metabolites were administered at 1800 hr in a liquid test meal containing radiolabeled taurocholate as an absorbable marker, 60% of lithocholylglycine was conserved, based on recovery of radioactivity in fasting bile the following morning, but only 20% of sulfolithocholylglycine was conserved. Iotope dilution studies in 4 subjects showed that daily input of lithocholate into the bile acid pool averaged 100 mg per day, about one-third to one-half of the chenodeoxycholic acid synthesis, but the t 1/2 was extremely short (0.74 day). The small lithocholate pool (about 100 mg) could be explained by rapid fecal excretion caused by sulfation which decreases passive absorption in the jejunum and active absorption in the ileum. Experiments with [35S]sulfo- [3H]lithocholylglycine indicated little desulfation during enterohepatic cycling but rapid desulfation in the distal intestine, with absorption of 35S (presumably as sulfate) followed by urinary excretion. A decreasing 35S:3H ratio in bile indicated that some steroid moiety was conserved to be resulfated. These studies indicate that considerable lithocholate is absorbed from the distal intestine in healthy subjects but efficient sulfation results in rapid fecal excretion, so that the total lithocholate pool remains small. A multicompartment model, previously used to describe the metabolism of the steroid and amino acid moieties of the major conjugated biliary bile acids, was extended to encompass lithocholyl conjugates and their sulfates.

Chenodeoxycholic Acid↗
PubMed1975

Thin-layer chromatographic separation of sulfated and nonsulfated lithocholic acids and their glycine and taurine conjugates.

A method for superior thin-layer chromatographic separation of lithocholic acid and its N-glycine and N-taurine conjugates, as well as their respective 3alpha-sulfates, is described. A solvent system of chloroform-methanol-acetic acid-water 65:24:15:9 (v/v) is used with air-dried plates of silicic acid containing calcium sulfate (10% by weight) under conditions of chamber saturation.

Cholic Acids↗
PubMed1975

Metabolism of lethocholate in healthy man. I. Biotransformation and biliary excretion of intravenously administered lithocholate, lithocholylglycine, and their sulfates.

The metabolism of intravenously injected radiolabeled lithocholate, lithocholylglycine, and their 3alpha-sulfate esters was characterized in healthy subjects. Lithocholate radioactivity was excreted rapidly and predominantly in bile; the excreted radioactivity had the chromatographic properties of glycine and taurine conjugates of lithocholate, of which 60% were sulfated. Lithocholylglycine also was excreted rapidly and predominantly in bile, and 60% of excreted radioacitvity was sulfated. Sulfolithocholate radioactivity was only partially conjugated (about 60%) in association with biliary excretion. Sulfolithocholylglycine was excreted unchanged in bile. Neither sulfated derivative showed appreciable excretion in urine, although both were excreted more slowly in bile than unsulfated free or conjugated lithocholate. The data suggest that unconjugated lithocholate which is absorbed is completely conjugated and partially sulfated before excretion which occurs exclusively in bile. Since sulfation is not complete, some unsulfated lithocholate is always present in bile. This conjugated but unsulfated lithocholate, if reabsorbed, would be again partially sulfated during its next enterohepatic circulation. Thus, the end result of these biotransformations would be for absorbed lithocholate to be excreted in bile mostly, but not entirely as the sulfated conjugates.

Bile↗