Biomedical subjects

R D Yusen

Publications and source records attributed to R D Yusen.

29 records · Page 2Linked to original sources

PubMed1997

Recent advances in surgery for emphysema.

Volume reduction surgery is based on the removal of volume-occupying but nonfunctioning emphysematous lung, which is thought to improve pulmonary elastic recoil. The reduction in thoracic volume may also improve thoracic cage and inspiratory muscle function. In addition, dyspnea is lessened, exercise tolerance is increased, and measured pulmonary function is improved. Alveolar gas exchange may also be improved. Selection criteria include marked airway obstruction secondary to emphysema, marked hyperinflation of the chest wall, and regional heterogeneity in the distribution of the emphysema. The best results are obtained with a bilateral procedure utilizing stapling resection. The two surgical approaches are median sternotomy and video-assisted thoracic surgery.

Endoscopy↗

PubMed1997

Patients with emphysema: quantitative CT analysis before and after lung volume reduction surgery. Work in progress.

PURPOSE: To quantitatively assess the morphologic changes in the lungs after lung volume reduction surgery and determine whether changes at quantitative computed tomography (CT) reflect changes in lung function. MATERIALS AND METHODS: In 10 patients, chest CT images were obtained at full inspiration and expiration before and after surgery. A semiautomated segmentation method was developed to isolate the lung regions and calculate the lung volumes and frequency distribution of attenuation values. The changes in lung volume and attenuation after surgery were compared with clinical findings, and an exploratory evaluation of outcome predictors was conducted. RESULTS: Semiautomated segmentation and quantitative analysis compared favorably with manual techniques, and there was good correlation between the emphysema indexes and percentage predicted forced expiratory volume in 1 second, forced expiratory volume in 1 second/forced vital capacity, and diffusing capacity. The emphysema index decreased from 60% to 38% at inspiration and from 60% to 27% at expiration after surgery. The average CT lung volume decreased from 7.5 to 5.6 L at inspiration (25%) and from 6.4 to 3.8 L (41%) at expiration after surgery and correlated well with measurements at plethysmography. CONCLUSION: Substantial decreases in the lung volumes and emphysema index, increased airflow, possible reexpansion of some remaining lung, and the relation between preoperative quantitative CT indexes and clinical outcome suggest a multifactorial mechanism for improvement seen after surgery.

Adult↗

PubMed1997

Lung volume reduction surgery: comparison of preoperative radiologic features and clinical outcome.

PURPOSE: To examine the relationship between preoperative radiologic findings and clinical outcome after lung volume reduction surgery. MATERIALS AND METHODS: In 50 consecutive patients, preoperative chest radiographs and computed tomographic (CT) scans were scored by four radiologists for features related to the severity and distribution of emphysema and compared with clinical improvement in forced expiratory volume in 1 second (FEV1), arterial partial pressure of oxygen, and exercise tolerance 6 months after surgery. RESULTS: In the 47 surviving patients, follow-up data showed greater postoperative improvement in function in patients with a global pattern of predominantly upper-lobe emphysema (P < .05) and in patients with a more heterogeneous distribution of emphysema, compressed lung, and a larger percentage of normal and mildly emphysematous lung (P < .05 for improvement in FEV1). Radiographic scores for individual features were more strongly correlated with outcome than CT scores. The combination of upper-lobe severity and percentage of normal and mildly emphysematous lung at CT were the strongest predictors of improvement in FEV1 (r2 = .49). The three patients who died were older (P = .05) and had more severe, diffuse emphysema compared with other patients. CONCLUSION: Imaging studies may help predict the degree of improvement and therefore should be considered an integral part of an objective patient selection process. Radiography alone may be adequate for initial screening.

Adult↗

PubMed1997

Pulmonary emphysema: comparison of preoperative quantitative CT and physiologic index values with clinical outcome after lung-volume reduction surgery.

PURPOSE: To compare quantitative computed tomographic (CT) and preoperative physiologic values in emphysema with outcome after lung-volume reduction surgery. MATERIALS AND METHODS: In 46 patients, emphysema was quantified by measuring lung attenuation on preoperative CT scans. Quantitative CT and preoperative physiologic values and postoperative outcomes (1-second forced expiratory volume, PaO2, and 6-minute walk distance) were compared. RESULTS: Moderately strong correlations were found between several quantitative CT and preoperative physiologic values (magnitude of r = .29-.58, P < .05) and several quantitative CT and outcome measures (magnitude of r = .31-.47, P < .05). With stratification, postoperative outcome was better with mean lung attenuation greater than -900 HU; 75% or greater of upper lung below -900 HU (emphysema index); greater than 25% of lung below -960 HU (severe emphysema index); ratio of upper- and lower-lung emphysema indexes 1.5 or greater; volume of normally attenuated lung (-850 to -701 HU) greater than 1 L; and full width at half maximum of attenuation-frequency distribution 80 HU or less. Differences in outcome measures between groups stratified with quantitative CT values were often two- to threefold; patients with greater numbers of favorable quantitative CT values had better outcome. Correlations between preoperative physiologic measures and outcome were few. CONCLUSION: In emphysema, quantitative CT values correlate with outcome. Quantitative assessment of emphysema in candidates for lung-volume reduction surgery is potentially useful.

Adult↗

PubMed1997

Perfusion scintigraphy in the evaluation for lung volume reduction surgery: correlation with clinical outcome.

PURPOSE: To identify preoperative pulmonary perfusion scintigraphic findings that might be associated with clinical outcomes after lung volume reduction surgery. MATERIALS AND METHODS: Preoperative perfusion scintigrams in 103 patients (56 men, 47 women; age range, 41-76 years; mean age, 61 years +/- 9) were reviewed and graded for emphysematous heterogeneity (from isolated areas to diffuse distribution), extent of maximally perfused lung, and lobar predominance (upper-lobe vs lower-lobe asymmetry). These findings were correlated with clinical outcome on the basis of pulmonary function, arterial blood gas levels, and exercise test results before and 6 months after surgery. RESULTS: Among the 96 patients who survived surgery, there was an average improvement of 47% in the forced expiratory volume in 1 second (FEV1), of 20% in arterial oxygen tension, and of 20% in the 6-minute walking distance. Scintigraphic markers correlated best with FEV1 improvement. The strongest scintigraphic predictor of increase in FEV1 was upper-lobe predominance (r = .38, P < .001), which was followed by heterogeneity (r = .31, P = .002). The seven patients who died had a significantly lower percentage of maximally perfused lung than the survivors (25% vs 34%, P = .004). CONCLUSION: Perfusion scintigraphy can provide modest prognostic information in patients who undergo evaluation for lung volume reduction surgery.

Adult↗

PubMed1996

Results of 150 consecutive bilateral lung volume reduction procedures in patients with severe emphysema.

Between January 1993 and February 1996, we performed 150 bilateral lung volume reduction procedures for patients with severe emphysema. Patients were selected on the basis of severe dyspnea, increased lung capacity, and a pattern of emphysema that included regions of severe destruction, hyperinflation, and poor perfusion. Twenty percent to 30% of the volume of each lung was excised with the use of a linear stapler and bovine pericardial strips attached to buttress the staple line. Patients were between 36 and 77 years old, with an average 1-second forced expiratory volume of 25% of predicted, total lung capacity of 142% of predicted, and residual volume of 283% of predicted. Ninety-three percent of patients required supplemental oxygen, continuously or with exertion. All patients but one were extubated at the end of the procedure. The 90-day mortality was 4%. Hospital stay progressively decreased with experience, and for the last 50 patients the median hospital stay was 7 days. Prolonged air leakage was the major complication. Results at 6 months show a 51% increase in the 1-second forced expiratory volume and a 28% reduction in the residual volume. The Pao2 increased by an average of 8 mm Hg, and 70% of the patients who had previously required continuous supplemental oxygen no longer had this requirement. The improvements in measured pulmonary function were paralleled by a significant reduction in dyspnea and an improvement in the quality of life. Reevaluation at 1 year and 2 years after operation showed the benefit to be well maintained. We conclude that lung volume reduction offers benefits not achievable by any means other than lung transplantation for highly selected patients with severe emphysema.

Adult↗

PubMed1996

Evaluation of patients with emphysema for lung volume reduction surgery. Washington University Emphysema Surgery Group.

Lung volume reduction surgery (LVRS) is performed to alleviate the dyspnea of patients with emphysema and improve performance in the activities of daily living. Removing diseased and functionless lung may improve the function of remaining, less diseased lung by (1) increasing elastic recoil pressure, thereby increasing expiratory airflow rates, (2) decreasing the degree of hyperinflation resulting in improved diaphragm and chest wall mechanics, and (3) decreasing inhomogeneity resulting in decreased work of breathing and improved alveolar gas exchange. The guidelines used for patient assessment were (1) airflow limitation with a forced expiratory volume in 1 second (FEV1) less than 35%, (2) hyperinflation and air trapping with total lung capacity more than 125% and respiratory volume more than 250% predicted, and (3) regional heterogeneity of the emphysematous process providing target areas for resection. We sought to exclude patients with the following: (1) obliteration of the pleural space by previous disease or surgery, (2) severe structural abnormalities of the thoracic cage, (3) PaCo2 greater than 55 mm Hg. (4) mean pulmonary artery pressure greater than 35 mm Hg. (5) predominant airway disease such as asthma, bronchiectasis, or chronic bronchitis with persistent excessive purulent secretions, (6) significant coexisting disease, and (7) maintenance corticosteroid therapy in excess of 10 mg prednisone per day. The assessment process continues to be evaluated by analysis of patient outcome.

Activities of Daily Living↗

PubMed1996

Results of lung volume reduction surgery in patients with emphysema. The Washington University Emphysema Surgery Group.

Between January 1993 and April 1995, 84 patients with emphysema underwent bilateral lung volume reduction surgery at Barnes Hospital, Fifty-three patients had completed 3 months; 37 patients, 6 months; and 19 patients, 1 year of follow-up. Significant improvement was observed in spirometric parameters, oxygenation, 6-minute walking distance, dyspnea indices, and quality-of-life scores. The average increases in FEV1 were 52%, 51%, and 61%, at 3,6, and 12 months, respectively, after surgery. The most common postoperative complication, prolonged ( > 7 days) chest tube drainage, was present in 63% of the cases, and the mean duration of hospitalization in the survivors was 15 days (range 5 to 49 days). This has been reduced to 11 days (median 7.5 days) for the subsequent 40 patients. Five postoperative deaths occurred, 2 in the first, 2 in the third, and 1 in the fifth postoperative month, respectively. The overall mortality in the 84 patients was 6%, and the actuarial survival at 1 year was 93%. Volume reduction surgery is a promising therapeutic option for patients with an appropriate pattern of emphysema. Improvement has been sustained for more than 1 year, and long-term follow-up is planned to ascertain the duration of the benefits.

Activities of Daily Living↗

PubMed1996

[Lung volume reduction surgery in advanced emphysema--results of the Washington University, St. Louis].

The aim of lung volume reduction surgery is to alleviate the symptoms of severe emphysema and to improve the life quality of the patient. The appropriate candidates (approximately 20% of all emphysematic patients examined in our clinic) had considerable dyspnea, an increased lung capacity, and a heterogenous dissemination of the emphysema with regional destruction of the parenchyma, hyperinflation and poor perfusion. After preoperative physiotherapie with a specified rehabilitation aim, a resection of 20 to 30% of the total lung volume was performed via sternotomy. From January 1993 to February 1996, 150 patients underwent bilateral lung volume reduction (age range = 36 to 77 years). The mean forced expiratory volume in 1 s (FEV1) was preoperatively 25% of the predicted value, the total lung capacity (TLC) 142% and the residual volume (RV) 283%, 94% of these patients necessitated oxygen supply at rest or during exercise. The 90-day mortality was 4%. All patients except 1 were extubated immediately after operation. The median hospital stay was 10 days in the first 100 patients and 7 days in the last 50. An increase of the FEV1 by 51% and a decrease of the RV by 28% was observed 6 months after operation. The mean PaO2 was improved by 8 mm Hg while the percentage of oxygen dependent patients went down from 50 to 16%. In addition a raise of the perseverance capacity, a clear decrease of dyspnea and an improvement of the life quality were achieved. These results persist after 1 (n = 56) and 2 (n = 20) years after operation. Lung volume reduction leads to an improvement of the lung function, symptoms and the quality of life, which is superior to that achieved by maximal clinical intervention.

Adult↗

PubMed1995

Acute respiratory failure due to extramedullary hematopoiesis.

Extramedullary hematopoiesis (EMH) associated with myelofibrosis uncommonly occurs within the thorax. We describe the first reported case of acute and rapidly fatal respiratory failure due to pulmonary interstitial EMH associated with myelofibrosis. Interstitial EMH should be considered in the differential diagnosis of patients with interstitial pulmonary infiltrates and respiratory failure accompanying a disease process known to predispose to the development of EMH.

Acute Disease↗

PubMed1989

The efficacy of blood cardioplegia is not due to oxygen delivery.

Twenty-seven canine hearts instrumented with ultrasonic dimension crystals underwent simultaneous determination of stroke work and myocardial oxygen consumption during incremental volume loading on right heart bypass before and 30 minutes after 2 hours of cardioplegic arrest at 10 degrees C. Three cardioplegic solutions were used: Hematocrit values were 17.0% (group I), 8.2% (group II), and 0% (group III). In all groups the slope of the linear stroke work versus end-diastolic volume relationship, a measure of contractility, was unchanged after ischemic arrest. However, the myocardial oxygen consumption for basal metabolism was increased an average of 25.5% after arrest with plasma (group III). Since the plasma concentration in all three groups was identical, and the oxygen available to the hearts during ischemia was the same in groups II and III, the efficacy of blood-based cardioplegic solutions cannot be attributed to a plasma component or to the greater oxygen-carrying capacity of the red blood cell. Future studies should attempt to identify the salutory entity of the red cell responsible for preservation of myocardial oxygen consumption efficiency.

Animals↗