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Biomedical subjects

U Stammberger

Publications and source records attributed to U Stammberger.

At least 37 records · Page 2Linked to original sources
PubMed1999

Lung volume reduction surgery combined with cardiac interventions.

OBJECTIVE: Postoperative course and functional outcome were evaluated in patients who underwent lung volume reduction surgery (LVRS) or in combination with valve replacement (VR), percutaneous transluminal coronary angioplasty (PTCA), placement of a stent, or coronary artery bypass grafting (CABG). METHODS: Patients with severe bronchial obstruction and hyperinflation due to pulmonary emphysema were evaluated for lung volume reduction surgery. Cardiac disorders were screened by history and physical examination and assessed by coronary angiography. Nine patients were accepted for LVRS in combination with an intervention for coronary artery disease (CAD). In addition, three patients with valve disease and severe emphysema were accepted for valve replacement (two aortic-, one mitral valve) only in combination with LVRS. Functional results over the first 6 months were analysed. RESULTS: Pulmonary function testing demonstrates a significant improvement in postoperative FEV1 in patients who underwent LVRS combined with an intervention for CAD. This was reflected in reduction of overinflation (residual volume/total lung capacity (RV/TLC)), and improvement in the 12-min walking distance and dyspnea. Median hospital stay was 15 days (10-33). One patient in the CAD group died due to pulmonary edema on day 2 postoperatively. One of the three patients who underwent valve replacement and LVRS died on day 14 postoperatively following intestinal infarction. Both survivors improved in pulmonary function, dyspnea score and exercise capacity. Complications in all 12 patients included pneumothorax (n = 2), hematothorax (n = 1) and urosepsis (n = 1). CONCLUSION: Functional improvement after LVRS in patients with CAD is equal to patients without CAD. Mortality in patients who underwent LVRS after PTCA or CABG was comparable to patients without CAD. LVRS enables valve replacement in selected patients with severe emphysema otherwise inoperable.

Aged↗
PubMed1999

Combined treatment with endothelin- and PAF-antagonists reduces posttransplant lung ischemia/reperfusion injury.

BACKGROUND: Pathophysiologic changes of posttransplant lung ischemia/reperfusion injury are mediated by redundant cellular and humoral mechanisms. We investigated the protective effect of combined administration of platelet activating factor (PAF) and endothelin (ET) antagonists after prolonged ischemia in a small animal lung transplantation model. METHODS: Orthotopic left lung transplantation was performed after 20 hours cold ischemia in male Fischer (F344) rats weighing 200-250 g. Group I served as control. In Group II, donors received 1 mg/kg body weight of the endothelin antagonist TAK-044, and recipients 2 mg/kg. Group III was treated with the PAF antagonist TCV-309 (donor: 50 microg/kg; recipient: 100 microg/kg) (Takeda Chemicals Ltd.). Group IV received a combined treatment with both substances at the same dosage. Twenty-four hours after reperfusion, the native contralateral lung was occluded to assess gas exchange of the graft only, and 5 minutes later the thoracic aorta was punctured for arterial blood gas analysis (n = 5). In other animals (n = 5), lung tissue was frozen 24 hours after reperfusion and assessed for myeloperoxidase activity (MPO) and thiobarbituric acid reactive substances. RESULTS: Combined inhibition of PAF and ET-1 at the receptor level resulted in significantly improved graft function as compared to controls (Group I), and to groups treated with either TAK-044 or TCV-309. This was determined by a higher arterial oxygen content (112 +/- 9 mmHg, p = .00061 vs control, 48 +/- 5 mmHg), reduced MPO activity (0.35 +/- 0.02 deltaOD/mg/min, p = .000002 vs control, 1.1 +/- 0.1 deltaOD/mg/min) and reduced lipid peroxidation (59.5 +/- 2.5 pmol/g, p = .011 vs control, 78.5 +/- 4.1 pmol/g). The improvement of arterial oxygen (Group II 77 +/- 10 mmHg, p = .027 vs control; Group III 84 +/- 8 mmHg, p = .0081 vs control) and reduction of MPO activity (Group II 0.85 +/- 0.061 deltaOD/mg/min, p = .017; Group III 0.92 +/- 0.079 deltaOD/mg/min, p = .058) in groups treated with either a PAF antagonist or an ET antagonist was significantly less than in Group IV. CONCLUSIONS: Combined donor and recipient treatment with an ET antagonist and a PAF antagonist results in superior posttransplant graft function 24 hours after reperfusion, suggesting a synergistic role of ET-1 and PAF in the mediation of reperfusion injury in this model. Single treatment with either of the antagonists revealed only a slight improvement compared to untreated controls.

Animals↗
PubMed1999

Role of lung perfusion scintigraphy in relation to chest computed tomography and pulmonary function in the evaluation of candidates for lung volume reduction surgery.

Lung perfusion scintigraphy is employed to evaluate patients with severe emphysema who are candidates for lung volume reduction surgery (LVRS). Our purpose was to investigate the role of scintigraphy in relation to chest computed tomography (CT) and lung function in this setting. Six observers blinded to clinical data retrospectively scored preoperative scintigrams of 70 patients undergoing bilateral video-assisted LVRS according to the distribution of lung perfusion as homogeneous, intermediately heterogeneous, or markedly heterogeneous. Heterogeneity of emphysema distribution was also assessed by chest CT. Dyspnea and pulmonary function were measured preoperatively and 3 mo postoperatively. In 42 patients with markedly heterogeneous, in 18 with intermediately heterogeneous, and in 10 with homogeneous perfusion, mean (+/- SE) FEV1 increased by 57 +/- 8% (p < 0.0001), 38 +/- 9% (p < 0.001), and 23 +/- 9% (p = NS) (p = NS for intergroup comparisons). In a multiple regression analysis, functional improvement after LVRS was more closely correlated with preoperative hyperinflation and the degree of emphysema heterogeneity estimated by chest CT than with the degree of perfusion heterogeneity assessed by scintigraphy. In 16 of 22 patients with homogeneous emphysema distribution in the chest CT scintigraphy revealed intermediately or markedly heterogeneous perfusion. We conclude that lung perfusion scintigraphy has a limited role in prediction of outcome, but it may help to identify target areas for resection in LVRS candidates with homogeneous CT morphology.

Adult↗
PubMed1998

Effect of lung volume reduction surgery on pulmonary hemodynamics in severe pulmonary emphysema.

OBJECTIVE: The presence of pulmonary hypertension in severe pulmonary emphysema has been considered a relative contraindication to lung volume reduction surgery (LVRS). There was concern that resection of lung tissue might further increase pulmonary artery pressure. To address this point, the prevalence of pulmonary hypertension in candidates for LVRS was investigated. The changes in pulmonary artery pressures after bilateral videoassisted thoracoscopic resection was studied in patients with homo- and heterogeneously destroyed emphysematous lungs. DESIGN: The pulmonary arterial pressures by right heart catheterization were prospectively assessed, before and 6 months after LVRS in 21 consecutive patients (15 males, six females, mean (+/- S.E.) age: 62 +/- 1.9, range 42-74 years). All were former smokers and three had ZZ-AT1 deficiency. The inclusion criteria were: (a) severe bronchial obstruction (FEV1 < 35% predicted); (b) pulmonary hyperinflation (RV/TLC > 0.60); and (c) absence of hypercapnia (PaCO2 < 50 mmHg). RESULTS: The FEV1 had increased from 28 +/- 2% to 35 +/- 3% of the predicted value (P < 0.05) 6 months after surgery. The RV/TLC had declined from 0.65 +/- 0.02 to 0.55 +/- 0.02; PaO2 increased (66 +/- 1 versus 71 +/- 2 mmHg, P = 0.04), PaCO2 (38 +/- 2 versus 36 +/- 1 mmHg, P = 0.26) did not change. The pulmonary artery mean pressure (PAPmean) remained unchanged (18 +/- 1 versus 19 +/- 1 mmHg, P = 0.26). In six patients PAPmean was > or = 20 mmHg (up to 24 mmHg) preoperatively. After 6 months, six patients had a PAPmean > or = 20 mmHg (up to 31 mmHg). CONCLUSIONS: In patients with severe emphysema who are candidates for LVRS (but have only mild to moderate hypoxemia and a PaCO2 < 50 mmHg) we found no relevant pulmonary hypertension and pulmonary artery pressure did not change significantly after surgery. Therefore, routine right heart catheterization is not mandatory for preoperative evaluation.

Adult↗
PubMed1998

Effect of a short period of warm ischemia after cold preservation on reperfusion injury in lung allotransplantation.

OBJECTIVE: A short period of warm ischemia during lung allograft implantation is inevitable. We studied the effect of 2 h of warm ischemia before implantation after 18 h of cold preservation on reperfusion edema and pulmonary hemodynamics in a large animal model. METHODS: Left lung transplantation was performed in ten weight-matched pigs (25-31 kg). Donor lungs were flushed with 1.5 l cold (1 degree C) LPD solution and preserved for 20 h. In Group I (n = 5) the grafts were preserved for 20 h at 1 degree C and topically cooled with ice slush during implantation until reperfusion. In Group II (n = 5) lungs were stored at 1 degree C for 18 h followed by 2 h preservation at room temperature (20 degrees C). Topical cooling was not used during implantation. At 1 h after reperfusion the recipient contralateral right pulmonary artery and bronchus were ligated to assess graft function only. Extravascular lung water index (EVLWI), intrathoracic blood volume (ITBV), mean pulmonary artery pressure (PAP) and cardiac output (CO) were assessed during a 4 h observation period. Quantitative myeloperoxidase (MPO) activity and thiobarbituric acid-reactive substance (TBARS) levels as an indicator for lipid peroxidation were determined in allograft tissue samples taken 5 h after reperfusion. RESULTS: In Group II a tendency to improved pulmonary vascular resistance and cardiac output was noted. Surprisingly, lung edema, assessed by EVLWI, did not increase in animals with warm ischemia. Even a tendency to a reduced EVLWI was noted. However, differences between groups did not reach statistical significance. Gas exchange did not differ statistically significant between groups. CONCLUSION: Our results indicate that a short period of warm ischemia before reperfusion does not lead to increased pulmonary edema. In animals with a short period of warm ischemia before reperfusion, even a tendency to reduced posttransplant lung reperfusion injury was noted. In this model, topical graft cooling during lung implantation did not improve posttransplant graft function.

Animals↗
PubMed1998

Bronchial manifestation of acute febrile neutrophilic dermatosis (Sweet's syndrome).

We describe a 62 yr old female with acute febrile neutrophilic dermatosis (AFND) or Sweet's syndrome, involving the bronchial mucosa. The patient presented with classical skin manifestations of AFND accompanied by bilateral pneumonia, pleural effusions and lesions of the oral mucosa. The diagnosis was confirmed by skin and mucosal biopsies. Bronchoscopy revealed raised pustules, similar to the lesions of the skin, suggesting bronchial involvement of AFND. The patient responded to systemic corticosteroids only for a short period and died as a result of multiorgan failure. Postmortem findings confirmed dense, focal neutrophilic infiltrates of the bronchi and bronchioles. No underlying disease was found.

Bronchial Diseases↗
PubMed1998

Exercise performance and gas exchange after bilateral video-assisted thoracoscopic lung volume reduction for severe emphysema.

Lung volume reduction surgery (LVRS) improves dyspnoea and pulmonary function in selected patients with severe emphysema. The purpose of this study was to assess the effects of LVRS on exercise performance and gas exchange in relation to changes in pulmonary function. In 40 patients (63.2+/-1.4 yrs, mean+/-SE) with severe emphysema (forced expiratory volume in one second (FEV1) 29+/-1% predicted, residual volume/total lung capacity (RV/TLC) ratio: 0.63+/-0.01) we assessed dyspnoea, pulmonary function and exercise performance before and 3 months after bilateral video-assisted thoracoscopic LVRS. The Medical Research Council dyspnoea score fell from 3.5+/-0.1 to 1.4+/-0.1 (p<0.0005); FEV1 increased by 55+/-9% to 44+/-2% pred (p<0.0005), RV/TLC decreased from 0.63+/-0.01 to 0.51+/-0.02 (p<0.0005). The diffusing capacity remained unchanged. Maximal work load during bicycle ergometry increased from 34.3+/-2.0 to 48.9+/-2.4 W (p< 0.0005), maximal oxygen uptake (V'O2max) from 10.0+/-0.4 to 12.8+/-0.3 mL x kg(-1) x min(-1) (p<0.0005). The increase in maximal ventilation during exercise (V'Emax) from 29.5+/-1.5 to 38.6+/-1.8 L x min(-1) (p<0.0005) was associated with increases in tidal volumes at isowatt and maximal exercise while corresponding breathing frequencies remained unaltered. The increases in V'O2max and V'Emax correlated with the increases in FEV1 and the decreases in RV/TLC. We conclude that the improvement in pulmonary hyperinflation and airflow obstruction after bilateral thoracoscopic lung volume reduction surgery may reduce ventilatory limitation, thereby increasing exercise capacity.

Adult↗
PubMed1998

[Functional results after bilateral thoracoscopic lung volume reduction surgery in emphysema].

We investigated functional results, complications and survival of patients undergoing bilateral video-assisted thoracoscopic (VAT) lung volume reduction surgery (VRS) for severe, diffuse pulmonary emphysema [FEV1 28 +/- 0.8 (% pred.), RV/TLC 0.65 +/- 0.01, 12' walking distance 499 +/- 21 (m)]. From January 1994 to March 1998, 106 of 286 candidates were operated, 85 patients (mean age 64, range 38-78 years, 30 females) fulfilled the study criteria and were included in the prospective study. Hyperinflation decreased to an RV/TLC ratio of 0.51 +/- 0.01 after 3 months and 0.55 +/- 0.02 after 24 months, FEV1 increased to 43 +/- 1.6 (% pred.) after 3 months and 35 +/- 2.3 (% pred.) after 24 months, and the 12' walking distance was 687 +/- 29 (m) 3 months postoperative and 626 +/- 44 (m) after 24 months.

Adult↗
PubMed1997

Radiologic emphysema morphology is associated with outcome after surgical lung volume reduction.

BACKGROUND: Lung volume reduction surgery is known to alleviate dyspnea and to improve pulmonary function, performance in daily activity, and quality of life in selected patients with severe pulmonary emphysema. We investigated the role of radiologically assessed emphysema morphology on functional outcome after a lung volume reduction operation. METHODS: The preoperative chest computed tomograms in 50 consecutive patients who had undergone surgical lung volume reduction were retrospectively reviewed by 6 physicians blinded to the clinical outcome. Emphysema morphology was determined according to a simplified classification (ie, homogeneous, moderately heterogeneous, and markedly heterogeneous; lobe predominance). We studied the impact of these morphologic aspects on functional outcome at 3 months. RESULTS: We found a fair interobserver agreement applying our classification system. Functional improvement after surgical lung volume reduction was best in markedly heterogeneous emphysema with an increase in forced expiratory volume in 1 second of 81% +/- 17% (mean +/- standard error, n = 17) compared with 44% +/- 10% (n = 16) for intermediately heterogeneous emphysema. But also in patients with homogeneous emphysema clinical relevant improvement of function could be observed (increase in forced expiratory volume in 1 second = 34% +/- 6%; n = 17). CONCLUSIONS: The morphologic type of emphysema, assessed by a simplified surgically oriented classification, is an important predictor of surgical outcome. Lung volume reduction surgery may also improve dyspnea and lung function in homogeneous emphysema.

Adult↗
PubMed1997

Thoracoscopic bilateral lung volume reduction for diffuse pulmonary emphysema.

OBJECTIVE: In a prospective study, we investigated the functional results, complications and survival of bilateral video-assisted thoracoscopic (VAT) lung volume reduction (LVR) in a selected group of patients with severe, nonbullous pulmonary emphysema. From January 1994 to September 1996, 42 of 143 candidates (13 female, 29 male, 42-78 years) were operated. They were short of breath on minimal exertion due to severe airflow obstruction and hyperinflation (FEV1 < 30%) pred., TLC > 130% pred., RV > 200% pred.). METHODS: LVR was performed bilaterally by VAT using endoscopic staplers without buttressing the staple lines. Pulmonary function test (PFT), MRC dyspnea score and 12 min walking distance were assessed preoperatively, at 3, 6 and 12 months. In addition lung function was measured at hospital discharge. RESULTS: The patients reported a marked relief of dyspnea, which persisted at all follow-up visits (P<0.001). FEV1 increased from 0.80 +/- 0.24 (L) to 1.14 +/- 0.41 (L) postoperatively, a 43% gain (P < 0.001). A relevant increase of FEV1 persisted for at least 1 year. The residual volume to total lung capacity ratio decreased from 0.64 to 0.56 at hospital discharge. The mean 12 min walking distance increased from 500 +/- 195 (m) to 770 +/- 222 (m) after 1 year (P < 0.001). The mean hospital stay was 13 +/- 5.5 days (median 12.0), drainage time was 9 +/- 4.3 (median 8.0) days. There was no 30 day mortality. Three patients died between 2 and 15 months postoperatively by non surgery related reasons. One patient underwent lung transplantation 5 months after surgical lung volume reduction. CONCLUSIONS: In a selected group of patients with severe, nonbullous pulmonary emphysema, bilateral LVR by VAT results in instantaneous postoperative improvement in pulmonary function and dyspnea. These favorable effects, including an amelioriation in exercise performance, lasted for at least 1 year.

Adult↗
PubMed1997

Video-assisted thoracoscopic volume reduction surgery in patients with diffuse pulmonary emphysema: gas exchange and anesthesiological management.

Arterial blood gases were studied prospectively using continuous intraarterial blood gas monitoring during thoracoscopic volume reduction surgery (VRS) in 24 patients with advanced diffuse pulmonary emphysema. Additionally, the early postoperative course (48 h) of arterial blood gases was studied retrospectively. Twenty-six operations were performed using a combination of thoracic epidural and general anesthesia with left-sided double-lumen intubation for one-lung ventilation (OLV). Arterial blood gases were determined awake, during two-lung ventilation prior to surgery, during OLV (extreme values), and after tracheal extubation. Additionally, the extremes during the whole procedure were determined: avoiding excessive peak inspiratory pressures (26.4 +/- 7.0 cm H2O), minimum PaO2 was 77 +/- 39 mm Hg (mean +/- SD), maximum PaCO2 65 +/- 14 mm Hg (P < 0.0001 versus preoperative values), and minimum pHa 7.22 +/- 0.08 (P < 0.0001). One tension pneumothorax occurred during OLV. Immediate postoperative extubation was performed in 25 of 26 cases, reintubation was necessary in two cases. One patient with coronary artery disease died 36 h after surgery. Hypercapnia (maximum PaCO2 49 +/- 8 mm Hg, minimum pHa 7.37 +/- 0.04, P < 0.01) was still observed 48 h after surgery. These results demonstrate that adequate oxygenation can be preserved during OLV for VRS, but CO2 elimination is impaired. However, intraoperative hypercapnia and immediate postoperative tracheal extubation are well tolerated.

Adult↗
PubMed1997

Lung volume reduction surgery for emphysema.

Lung volume reduction surgery (LVRS) is performed to alleviate dyspnoea of selected patients with severe pulmonary emphysema and to improve their pulmonary function, performance in daily activity and quality of life. By resection of destroyed lung areas the achievable improvements in function may consist of: 1) a reduction in hyperinflation resulting in amelioration of diaphragm and chest wall mechanics; 2) an increase of elastic recoil pressure, thereby augmenting expiratory flow rates; and 3) possibly an improvement in gas exchange. Meticulous selection of suitable patients, refinements in operative techniques, anaesthesiological and postoperative management has lowered perioperative mortality to less than 5% in groups who are experienced with this type of procedure. The best functional results are achieved by bilateral resection, which can either be performed by median sternotomy or by video-assisted thoracoscopy (VAT). The average increase in forced expiratory volume in one second (FEV1), obtained by bilateral resection in patients already receiving optimal medical therapy ranges 32-93%, and the reduction in hyperinflation, assessed by a decrease in total lung capacity ranges 15-20%. These favourable improvements have been reported to last in most of the patients for at least one year.

Activities of Daily Living↗
PubMed1997

Coronary artery disease in patients undergoing lung volume reduction surgery for emphysema.

OBJECTIVES: Most patients with severe pulmonary emphysema referred for lung volume reduction surgery (LVRS) have a long-standing history of cigarette smoking. Coronary artery disease (CAD) predisposes to perioperative cardiac complications. Since symptoms and signs of myocardial ischemia are often absent in patients with severe ventilatory impairment even during exercise, we investigated the prevalence of CAD in candidates for LVRS by angiography. DESIGN: We prospectively studied the prevalence of CAD by angiography and assessed the CAD risk factor profile in 41 candidates for LVRS (26 men, 15 women; mean age, 66+/-6.8 years; range, 52 to 76 years), who had no current symptoms or a history of myocardial ischemia. RESULTS: In six patients (15%), asymptomatic but significant coronary lesions (> 70% stenosis) were detected. In five patients, these findings altered the clinical management. Patients with CAD had significant higher cholesterol levels, tended to have smoked more, and had more often additional vascular risk factors. CONCLUSIONS: We found a high prevalence of angiographically significant but clinically silent CAD in this particular population of heavy smokers with advanced emphysema.

Aged↗
PubMed1997

[Bilateral video-assisted thoracoscopic volume reduction surgery for treatment of advanced pulmonary emphysema].

In a prospective study, we investigated the functional results, complications, and survival of patients who underwent bilateral video-assisted thoracoscopic (VAT) lung volume reduction surgery (VRS) for severe, diffuse pulmonary emphysema (FEV1 0.77 +/- 0.03 [1], RV/TLC 0.65, 12' walking distance 482 +/- 26 [m]). From January 94 to March 97, 67 of 179 candidates underwent the operation, and 58 patients (mean age 64 +/- 1.1, range 42-78 years; 17 women) fulfilled the study criteria. There was no 30-day mortality; hyperinflation decreased to an RV/TLC ratio of 0.52 +/- 0.01 after 3 months; FEV1 increased to 1.2 +/- 0.08 [1]; and the 12' walking distance was 687 +/- 29 [m].

Adult↗
PubMed1994

Spatial measurement and transformation of muscular attachments at the lower extremity.

A large number of spatial coordinates were directly measured on two wet anatomical muscle specimens with a measuring device specifically designed to collect cylindrical coordinates. Three-dimensional coordinates of muscle attachment circumferences, joint centres and bone landmarks were collected. All the measured points of a segment, including the adjacent joint centres, were referred to a reference system defined by three marked screw heads at the femur and tibia. The points of the pelvic segment were referred to three marks on a lumbar mounting plate. This approach allows one to define and to transform the data to any reference frame.

Aged↗
PubMed1994

[Predicting load bearing of the hip joint. Computerized analysis with a 3-D multibody model of the human].

Multibody analysis was applied to construct an advanced model of the human body, where the large joints and complete mass and inertial properties were implemented. The model represents the 50th-percentile rank of a male adult. The hip joint is controlled by three muscle forces. The muscle coordinates were taken from a data source, previously collected by our group. The model enables one to analyze 3D hip joint forces with respect to various joint angles and represents conceptually an improvement of the classical method of graphical statics, which was established by Pauwels [15]. A hip joint load of three times body weight was found in the single leg stance. A load of 3.7 times body weight was calculated when simulating a knee flexion angle of 90 degrees, and a ventral inclination of the resultant hip joint force was seen. A constant amount of gluteus medius muscle force was observed during flexion. An increasing flecting moment at the hip joint, however, had to be balanced by a significantly increased gluteus maximus muscle force. As a consequence, torsional forces can be studied by the system presented here and should also be considered when testing stems of hip prostheses. External muscle and joint forces are provided and can be used as input data for stress analyses.

Adult↗
PubMed1993

[Experimental determination of muscle coordination of the lower extremity].

In order to describe the lines of action of muscles acting on joints, data on the geometrical position of insertions and origins are needed. These are of fundamental relevance for the biomechanical analysis, in particular for the calculation of joint loading. A measuring device with an accuracy of 0.1 mm was designed and constructed for the collection of three-dimensional experimental data from wet anatomical specimens. The main design features of the device include a vertically adjustable stand on wheels and a rotatable scale ring with a radial pointer. After setting the reading, the apparatus permits the measurement of cylindrical coordinates The margins of the attachments of muscles acting on the hip and knee joints were measured in two specimens. Two extensive sets of morphological data are now available and can be used to create complex biomechanical computer models.

Biomechanical Phenomena↗