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Biomedical subjects

Douglas B Nelson

Publications and source records attributed to Douglas B Nelson.

At least 19 recordsLinked to original sources
PubMed2006

Endoscopic ultrasound and positron emission tomography for lung cancer staging.

BACKGROUND AND AIMS: Accurate assessment of mediastinal lymph nodes is vital for optimum treatment allocation in lung cancer patients. Currently available strategies fail to identify many patients with advanced mediastinal disease, resulting in unnecessary surgery. We prospectively compared 2 promising new modalities, positron emission tomography (PET) and endoscopic ultrasound (EUS), for staging mediastinal lymph nodes. METHODS: Consenting patients with lung cancer who also were suitable candidates for surgery were enrolled in the study. Patients underwent both PET and EUS. Outcomes were analyzed by surgery results or follow-up with serial imaging. RESULTS: Seventy-two eligible patients were enrolled, and adequate data were available for 65 patients. The final diagnosis was based on tissue analysis in 59 patients and 1-year radiologic follow-up evaluation in 6 patients. PET correctly diagnosed mediastinal lymph node status in 77% of patients, and EUS fine-needle aspiration was correct in 94% of patients (P = .012). The overall sensitivity, specificity, and accuracy of PET were 61%, 91%, and 77% compared with 87%, 100%, and 94% for EUS. We estimated that EUS obviated a surgical procedure in 55% (95% confidence interval, 40%-69%) of patients with radiologic evidence of mediastinal metastasis, and in 22% (95% confidence interval, 10%-41%) of patients without radiologic evidence of mediastinal metastasis. CONCLUSIONS: EUS fine-needle aspiration was more accurate than PET in staging mediastinal lymph nodes in lung cancer patients, and resulted in a substantial reduction in mediastinoscopy and thoracotomy.

Aged↗
PubMed2005

Recent advances in epidemiology and prevention of gastrointestinal endoscopy related infections.

PURPOSE OF REVIEW: This article reviews recent publications relevant to endoscope reprocessing and the potential for transmission of infection during gastrointestinal endoscopy. RECENT FINDINGS: There have been a number of established reprocessing failures of gastrointestinal endoscopes at various healthcare facilities across the US resulting in patient notifications. These episodes have been associated with user errors and reprocessing equipment failures, highlighting the need for increased compliance with established guidelines. Surveillance cultures may be useful to monitor the outcome of reprocessing, although their use is controversial. New technology to allow point-of-use monitoring is promising. Biofilm accumulation may be an issue when reprocessing gastrointestinal endoscopes. Although peracetic acid has been promoted as superior to aldehyde-type liquid chemical germicides with regard to soil fixation, it may only be a modest improvement. Electrolyzed acid water is an emerging liquid chemical germicide that may be equivalent to currently accepted disinfectants. There appears to be no benefit to an additional reprocessing cycle before use for endoscopes that have been appropriately cleaned, disinfected, and stored. SUMMARY: With the recent media attention on gastrointestinal endoscope reprocessing failures, despite the absence of documented transmission of infection, increased compliance with existing guidelines and new initiatives to enhance endoscope reprocessing are increasingly important to maintain public confidence.

Biofilms↗
PubMed2003

Infection control during gastrointestinal endoscopy.

Infection-control issues during gastrointestinal endoscopy, which are becoming increasingly important, can generally be divided into three major areas: (1) infectious complications resulting from a patient's own microbial flora (autologous), (2) infections transmitted from patient to patient by way of the endoscope (exogenous), and (3) infections transmitted between the patient and the health-care provider. The mean frequency of postprocedure bacteremia ranges from 0.5% for flexible sigmoidoscopy to 2.2% for colonoscopy, 4.2% for esophagogastroduodenoscopy, 8.9% for variceal ligation, 11% for endoscopic retrograde cholangiopancreatography, 15.4% for variceal sclerotherapy, and 22.8% for esophageal dilation. Although postprocedure bacteremia is not uncommon, it seldom results in infectious complications. Exogenous infections transmitted during endoscopy, which are extremely rare, generally result from failure to follow accepted guidelines for the cleaning and disinfection of gastrointestinal endoscopes, underscoring the importance of meticulous attention to endoscope reprocessing. Finally, although the risk of patient-staff transmission of infection is also rare, standard infection-control recommendations are important in protecting both patients and health-care providers.

Antibiotic Prophylaxis↗
PubMed2003

Multi-society guideline for reprocessing flexible gastrointestinal endoscopes. Society for Healthcare Epidemiology of America.

Flexible gastrointestinal endoscopy is a valuable diagnostic and therapeutic tool for the care of patients with gastrointestinal and pancreaticobiliary disorders. Compliance with accepted guidelines for the reprocessing of gastrointestinal endoscopes between patients is critical to the safety and success of their use. When these guidelines are followed, pathogen transmission can be effectively prevented. Increased efforts and resources should be directed to improve compliance with these guidelines. Further research in the area of gastrointestinal endoscope reprocessing should be encouraged. The organizations that endorsed this guideline are committed to assisting the FDA and manufacturers in addressing critical infection control issues in gastrointestinal device reprocessing.

Cross Infection↗
PubMed2003

Acute GI bleeding in the setting of supratherapeutic international normalized ratio in patients taking warfarin: endoscopic diagnosis, clinical management, and outcomes.

BACKGROUND: Acute GI bleeding is a life-threatening complication of warfarin therapy. Acute GI bleeding in patients with an international normalized ratio of 4.0 or greater (supratherapeutic) is often attributed to trivial mucosal lesions. The aim of the study was to determine the frequency of potentially significant lesions that would warrant endoscopy in this setting. METHODS: A retrospective review was conducted of patients treated with warfarin who were admitted to a single Veterans Affairs hospital from 1996 to 2000 with acute GI bleeding. Endoscopic findings, clinical management, and outcomes are reviewed for patients with a supratherapeutic international normalized ratio (>or=4.0) and compared with patients with an international normalized ratio in the therapeutic range (2.0-3.9). RESULTS: Fifty-five patients with an international normalized ratio of 4.0 or greater (mean 8.4 [3.9]) and 43 patients with an international normalized ratio between 2.0 and 3.9 (mean 2.9 [0.6]) were hospitalized with acute GI bleeding. Thirty-seven patients (67%) with a supratherapeutic international normalized ratio and GI bleeding underwent upper endoscopy. Of these, 81.1% had positive findings, 18.9% had peptic ulcer disease, and 7.2% required endoscopic treatment. Thirty-eight percent of the patients with a supratherapeutic international normalized ratio underwent lower endoscopy; of these, 57.1% had abnormal findings and 9.5% required endoscopic treatment. Four patients (7.3%) in the supratherapeutic international normalized ratio group died during the index hospitalization. When patients with GI bleeding and a therapeutic international normalized ratio were compared with those with a supratherapeutic international normalized ratio, there were no significant differences between the two groups with regard to days of hospitalization, units of blood transfused, frequency of recurrent bleeding, need for surgery, or in-hospital deaths. CONCLUSIONS: The high frequency of clinically significant lesions in patients taking warfarin with an international normalized ratio in the supratherapeutic range and acute GI bleeding supports a role for endoscopic evaluation.

Acute Disease↗
PubMed2002

Mucosal plasma cell repertoire during HIV-1 infection.

Impaired development of local Ab responses may predispose HIV-1-infected patients to an increased rate, severity, and duration of mucosal infections. We characterized the repertoire of Ig-producing cells in the intestinal effector compartment (the lamina propria) of HIV-1-infected (n = 29) and seronegative control (n = 27) subjects. The density of Ig-producing cells per area was similar in both groups. However, the proportions of IgA-producing cells were lower in both the duodenum and colon from HIV-1-infected patients compared with those of control subjects (p < 0.05), with compensatory increases in IgG-producing cells in the colon and IgM-producing cells in the duodenum. Similarly, among Abs in the lumen the proportions of IgA were also decreased and the proportions of IgG were increased among HIV-1-infected patients. On a molecular level, V(H) gene repertoire analyses by RT-PCR revealed comparable proportions of the V(H)3 family among duodenal IgA transcripts (50-53%) from both groups. V(H)3 expression was decreased only for IgM among patients with advanced HIV-1 disease (n = 6) compared with that of control subjects (n = 8) (48 +/- 8 vs 62 +/- 13%; p < 0.01). Moreover, the frequencies of individual IgM and IgA V(H)3 genes were comparable in each group, including rates of putative HIV-1 gp120-binding V(H)3 genes (V3-23, V3-30, V3-30/3-30.5). We conclude that, despite a decrement in local IgA producing cells, the density and molecular V(H) repertoire of mucosal plasma cells are relatively intact among patients with HIV-1 infection. These data suggest that HIV-1-infected patients use functional regulatory mechanisms to provide sufficient V(H) diversity and effective induction and differentiation of mucosal B cells.

Adult↗
PubMed2002

New technology in the endoscopy center.

The boundaries of endoscopy will continue to expand. Imaging modalities, such as high-resolution and high magnification endoscopy, tissue spectroscopy, optical coherence tomography, and wireless endoscopy, will continue to evolve. New therapeutic modalities, such as endoscopic antireflux procedures, are making endoscopic surgery a reality. In the increasingly restrictive reimbursement environment, however, it is critical to establish the cost-effectiveness of these new technologies to integrate them into daily practice.

Ambulatory Care Facilities↗