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Biomedical subjects

B S Lewis

Publications and source records attributed to B S Lewis.

At least 271 records · Page 15Linked to original sources
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Diazepam versus midazolam (versed) in outpatient colonoscopy: a double-blind randomized study.

Midazolam is a new parenteral benzodiazepine premedication for endoscopy. Consecutive patients were randomized to receive either intravenous midazolam or diazepam as premedication for outpatient total colonoscopy by one endoscopist. Fifty-five patients received diazepam (0.15 mg/kg) and 50 received midazolam (0.07 mg/kg). Both patient and endoscopist were blind to the study drug used. The two groups were similar with respect to age, sex, and indication for colonoscopy. Patients were rated by the endoscopist for degree of cooperation, sedation, and pain during examination. There was significantly more oversedation in the midazolam group than in the diazepam group (p less than 0.05). Immediate procedure recall was less in midazolam patients (p less than 0.005), but on repeat interview the next day there was no difference between the two groups concerning recall of the endoscopy. There was no significant difference between the two groups in the incidence of arm pain. We conclude that in a clinical setting, midazolam does not appear to offer any significant advantage over diazepam, except for cost. Midazolam carries an increased risk of oversedation when it is administered on a milligram per kilogram basis and should instead be titrated individually.

Ambulatory Care↗
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Perform PEJ, not PED.

Explore the source record for details and available documents.

Duodenogastric Reflux↗
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The technique of abdominal pressure in total colonoscopy.

Total colonoscopy can be difficult. It is recognized that abdominal pressure can be helpful in the performance of colonoscopy by externally splinting the endoscope to prevent loop formation. Properly applied abdominal pressure can limit patient discomfort and shorten examination time. Various techniques for abdominal pressure were studied in 201 consecutive patients who had total colonoscopy to the cecum. Abdominal pressure or change of body position was used 619 times in 165 patients (82%), with an average of 3.75 pressure applications per colonoscopy, most lasting less than 30 sec. Pressure was most commonly used when the endoscope tip was at the splenic flexure. Non-specific pressure to a region of the abdomen where looping developed, endoscopically observed specific pressure near the tip, and position change were used in a stepwise manner. Non-specific pressure was more successful in the left (78%) than in the right (47%) colon (p less than 0.0005). As intubation progressed left to right, specific pressure became more useful. When abdominal pressure was not useful, a change in patient position from left lateral to supine was successful in advancing the endoscope tip in 68% of patients.

Abdomen↗
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Colonoscopy and endoscopic therapy for delayed post-polypectomy hemorrhage.

Nine consecutive patients in whom endoscopic management of delayed post-polypectomy hemorrhage was attempted are described. Each patient presented with active rectal bleeding 12 hours to 12 days after snare resection of a colon polyp. In each patient, repeat colonoscopy identified the bleeding site and various combinations of injection therapy, electrocautery, or thermal injury led to cessation of hemorrhage. No complications resulted from repeat colonoscopy and endoscopic therapy. Colonoscopy and endoscopic therapy is feasible, effective, and safe in selected patients with active delayed post-polypectomy hemorrhage.

Colonic Polyps↗
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Control of inspiratory timing in newborn infants.

In order to determine if inspiratory time in preterm infants was influenced by lung volume, two studies were carried out. In the first investigation, carbon dioxide was used to stimulate tidal volume to a level three to six times normal. The anticipated decrease in inspiratory time at increased tidal volumes was not found. These preterm infants behaved in a similar fashion to vagotomized animals studied in the same way by Clark and von Euler. In the second investigation, Hering-Breuer activity was measured in relation to lung volume changes occurring with growth, measured in a body plethysmograph. Although thoracic gas volume correlated well with age and weight, inspiratory slowing with airway occlusion was found to be independent of both age and lung volume. These investigations suggest that neurologic factors have a significant influence on the inspiratory time in newborn human infants.

Airway Obstruction↗
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Determinants of improvement in exercise capacity in patients undergoing cardiac rehabilitation.

In order to identify patients who benefit most from a cardiac rehabilitation program, we studied retrospectively all patients who completed a 3-month comprehensive cardiac rehabilitation program during a 2-year period. Questionnaires regarding physical exercise habits were sent to 122 patients and returned by 117 (96%) of them (53 post-acute myocardial infarction, 50 post-coronary artery bypass surgery, 14 post-infarction and surgery, 2 post-angioplasty). Exercise capacity (subset of 66 patients) improved by 19% after rehabilitation (7.8 +/- 3.1 to 9.3 +/- 2.7 METs, p < 0.0001). Univariate and multivariate analysis identified initial exercise capacity as the only independent variable predicting improvement in exercise performance (inverse relationship) (r2 = 0.24, p < 0.0001). The improvement was not related to age, sex, left ventricular function or time from cardiac event to rehabilitation. Patients recovering from both infarction and coronary artery bypass surgery showed a greater improvement (delta exercise capacity 2.8 +/- 1.4 METs) than patients after myocardial infarction alone (delta exercise capacity 0.8 +/- 2 METs, p < 0.02). Improvement was sustained for up to 2 years after completion of the program.

Adult↗
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Use and limitations of immediate postprocedural intracoronary Doppler blood flow measurements for predicting late result after coronary balloon angioplasty. Results of a pilot study.

BACKGROUND AND AIMS: Physiologic measurement of myocardial perfusion in the immediate postangioplasty period may complement the angiographic assessment of the outcome of the procedure and improve our ability to identify patients at increased risk for a suboptimal late result. Immediate in-lab identification of patients at risk for late coronary restenosis would allow the interventionalist to implement alternate interventional and/or pharmacologic strategies aimed at improving the long-term outcome of angioplasty. The present single-center pilot study was undertaken to examine prospectively the value of intracoronary Doppler flow measurements immediately postangioplasty for predicting long-term patency of the dilated coronary artery. PATIENTS AND METHODS: Coronary average peak flow velocity (APV) at rest and during hyperemia (6-18 micrograms intracoronary adenosine) and coronary flow reserve in the distal coronary segment were measured in 24 consecutive patients 10-15 min after successful elective coronary angioplasty. Volume flow (Q) was calculated as APV/2 coronary cross-sectional area heart rate. Coronary arterial vessels and narrowings were measured by quantitative angiography using a geometric based method and automated edge detection. The present study reports the findings in the 16 patients undergoing conventional balloon angioplasty for whom hard endpoint angiographic data were available 4.9 +/- 1.5 months after angioplasty. RESULTS: A linear relation was present between angiographically measured minimal luminal dimension immediately postangioplasty and the late angiographic result of the procedure (r = 0.71, p = 0.0005). A greater acute gain during angioplasty was predictive of a larger luminal dimension at late angiographic follow-up (p = 0.006). There was no relation between the immediate postangioplasty Doppler flow measurements and the late angiographic result of the procedure. Late luminal dimension was not related to immediate postangioplasty basal or hyperemia APV, nor to immediate postangioplasty basal or hyperemic volume flow or to coronary flow reserve (all NS). CONCLUSIONS: In this single-center study, intracoronary blood flow and Doppler-derived coronary flow reserve immediately postpercutaneous transluminal coronary angioplasty were not predictive of long-term vessel patency or late coronary restenosis. The immediate angiographic result of angioplasty did correlate with the late result of the procedure.

Adult↗
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Exercise testing in patients with chest pain and normal coronary arteries: improving test specificity by use of a simple logistic model.

Despite an exercise electrocardiogram (ECG) positive for ischemia by established criteria, many patients referred for coronary angiography to evaluate chest pain are found to have angiographically normal coronary arteries (NCA). Exercise ECG were analyzed from 27 patients with chest pain and angiographically NCA and 28 patients with chest pain and coronary artery disease (CAD) using univariate and multivariate logistic regression analysis. We derived the following logistic model for the logit probability of CAD: 3 + SEX x 4 - METs x 0.7 + STDV5 x 0.8, where SEX = 0 for female and SEX = 1 for male, METs = maximal estimated work load (metabolic equivalents) and STDV5 = horizontal or downsloping ST depression (mm) in V5. A logit probability > or = 0 identified CAD with a sensitivity of 79% and a specificity of 89%. The model correctly identified 28/36 (78%) patients with CAD, and 7/10 (70%) patients with NCA (correct diagnosis 76%; p < 0.02) in a separate random group of 46 unselected patients with positive exercise tests undergoing diagnostic coronary angiography.

Adult↗
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Qualitative and quantitative methods for the assessment of clinical preceptors.

The improvement of clinical teaching skills has consistently been an important focus of faculty development in family medicine. Successful faculty development programs depend on an understanding of the components of clinical teaching and a profile of the strengths and weaknesses of each faculty member with respect to these components. In this study a system was developed to identify and measure specific faculty characteristics of inpatient preceptors. Complementary quantitative and qualitative approaches were employed. An analysis and comparison of the two approaches suggest that the measures result in a similar ranking of faculty, but that the qualitative approach identifies individual faculty strengths and weaknesses, which are more useful for providing feedback to stimulate and guide change.

Analysis of Variance↗