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T T Bauer

Publications and source records attributed to T T Bauer.

At least 37 records · Page 2Linked to original sources
PubMed2001

[The impact of different definitions of hypoxemia on the relation between awake pulmonary pressure and hypoxemia during sleep in patients with COPD].

BACKGROUND: Sleep related hypoxemia (SRH) in chronic obstructive pulmonary disease (COPD) can be easily detected by pulse-oximetry and may contribute to the development of pulmonary hypertension (PH). Since several parameters for the quantification of SRH are in use, we investigated which of these parameters has the strongest relation to the awake pulmonary arterial pressure (PAP) and is able to distinguish between patients without and with PH. PATIENTS AND METHODS: 44 COPD-patients (awake PaO2 > or = 60 mm Hg) were investigated. PAP at rest (PAP; pathological threshold > 20 mm Hg) and under physical exercise (PAPB; p.t. > 28 mm Hg) were determined during daytime by Swan-Ganz-catheter. To quantify the degree of SRH the following parameters of nocturnal pulse-oximetry were used: mean nocturnal oxygen saturation (SaO2 m; p.t. < 90%), nadir SaO2 (SaO2 min; p.t. < 85%), and mean time of SaO2 < or = 90% in relation to total time of registration (t90; p.t. > 30%). Linear correlations and regressions as Chi 2-respectively Fisher-test were used for statistical analysis (p < 0.05). RESULTS: Generally there was only a weak relation between PAP and SRH. The best linear correlation at rest respectively under physical exercise was found between PAP and SaO2 min (r = -0.529 resp. -0.541, p < 0.001). Using the above defined thresholds for PAP and SaO2 patients could be most precisely separated into those without and with PH using SaO2 min with a threshold for the pathological range of < 85% (p = 0.030 resp. 0.002). t90 with a threshold > 30%, however, had a much worse selectivity (p = 0.487 resp. 0.057). CONCLUSIONS: In COPD-patients with SRH the closest relation can be found between nadir SaO2 and PAP resp. PAPB. Furthermore nadir SaO2 (< 85%) could more precisely separate patients into those without and with pulmonary hypertension than t90. The overall weak relation between nocturnal oxygenation and pulmonary hypertension shows, however, that other factors such as daytime PaO2, hypercapnia or emphysema are involved in the development of pulmonary hypertension in COPD.

Blood Pressure↗
PubMed2001

Functional variables associated with the clinical grade of dyspnoea in coal miners with pneumoconiosis and mild bronchial obstruction.

OBJECTIVES: Dyspnoea is a common symptom in coal miners with pneumoconiosis. Among others, gas exchange disturbances due to airway obstruction or mismatch between ventilation and perfusion may be underlying mechanisms. The validation of dyspnoea by the degree of airway obstruction is controversial, because the extent of airway obstruction often does not correlate with the clinical grade of breathlessness. METHODS: The association was investigated between breathlessness (self reported, on a six point scale) and indices of submaximal spiroergometry in 66 coal workers with radiographically confirmed pneumoconiosis (International Labour Organisation (ILO) grade of profusion > or =1/0, mean (SD) age 64 (5.5) years, mean (SD) forced expired volume in 1 second (FEV(1)) 77.5 (22.9) % predicted). RESULTS: The clinical degree of breathlessness was independently associated with minute ventilation/oxygen consumption (VE/VO(2)) ratio (beta 0.423, 95% confidence interval (95% CI) 0.18 to 0.67, p=0.001) and smoking (beta 0.318, 95% CI 0.21 to 1.79, p=0.014) in a multiple linear regression analysis. The VE/VO(2) ratio (beta 0.556, 95% CI 0.20 to 0.90, p=0.003) was also the best predictor of breathlessness when only coal miners with airway obstruction (FEV(1) < 80% predicted) were analyzed. CONCLUSION: The VE/VO(2) ratio as a measurement of mismatch between ventilation and perfusion predicted the clinical grade of breathlessness better than measurements of bronchial obstruction at rest in coal workers with pneumoconiosis.

Aged↗
PubMed2001

Initial bacterial colonization in patients admitted to a respiratory intensive care unit: bacteriological pattern and risk factors.

BACKGROUND: Colonization is an important risk factor for consecutive infection, but little is known about incidence and initial pattern on admission to respiratory intensive care units (RICU). OBJECTIVE: To study the bacterial colonization during the first 24 h after admission to a RICU. METHODS: Endotracheal aspirates, gastric juice, and pharyngeal and rectal swabs of 55 consecutive patients were cultured (45 men, age 66 +/- 14 years, APACHE II 20.1 +/- 5.6, no parenchymal infection). All samples were taken within the first 24 h after admission to a RICU. Potentially pathogenic microorganisms were grouped as community (c-PPM) and hospital acquired (h-PPM), and risk factors for colonization of each body site as well as for overall colonization (all sites excluding rectum) were identified by logistic regression analysis. RESULTS: The trachea was colonized in 18% of the intubated patients with c-PPMs and in 11% with h-PPMs. Candida spp. were the most frequent c-PPMs isolated from trachea, pharynx, and stomach (excluding rectal swabs), and Pseudomonas aeruginosa was the most frequently isolated h-PPM in trachea. The incidence of overall colonization was 49% for c-PPMs (predominantly Escherichia coli) and 18% for h-PPMs (predominantly P. aeruginosa). Admission to the hospital > or = 48 h before ICU admission was an independent risk factor of colonization with h-PPMs in univariate (33 vs. 7%, p = 0.015) and multivariate analyses (odds ratio 7.2, 95% CI 1.4-38.3; p = 0.0197). CONCLUSIONS: Colonization of the trachea with c-PPMs was already present in every 5th and with h-PPMs in every 10th intubated patient during the first 24 h of RICU admission even in the absence of parenchymal infections. Hospitalization more than 48 h prior to RICU admission was a risk factor of colonization with h-PPMs.

Aged↗
PubMed2001

Systemic inflammatory response after bronchoalveolar lavage in critically ill patients.

Bronchoscopic bronchoalveolar lavage (BAL) may be followed by a systemic inflammatory response. Previous reports have suggested pneumonia as a predisposing condition and systemic cytokines as possible mediators. To test this hypothesis, systemic levels of interleukin (IL)-1beta, IL-6 and tumour necrosis factor-alpha (TNF-alpha) were studied before and at 12 h and 24 h after bronchoscopically guided BAL in 30 mechanically ventilated patients (median age 67 (range 54-76) yrs, simplified acute physiology score II (SAPS II) 33 (12-56)), 20 of whom had pneumonia and 10 of whom were control patients without pneumonia. Arterial oxygen partial pressure to inspired oxygen fraction ratio (Pa,O2/FI,O2), body temperature, mean arterial pressure, and cardiac frequency were recorded. The majority of patients (28/30, 93%) received antibiotic treatment prior to the procedure. Pa,O2/FI,O2 ratio was lower at 12 h compared to baseline in patients with pneumonia (baseline median 192 (range 65-256); 12 h 160 (66-190) mmHg, p<0.001) and ventilated controls (baseline 293 (205-473); 12 h 226 (153-330) mm Hg p=0.011), but returned to baseline levels at 24 h (pneumonia: 194 (92-312), p=0.991; controls: 309 (173-487) mmHg, p=0.785). No changes in other clinical variables were observed. Systemic TNF-alpha levels before BAL (pneumonia: 35 (10-88); controls: 17 (0-33) pg x mL(-1)) did not increase at 12 h (pneumonia: 35 (0-64); p=0.735; controls: 16 (0-21) pg x mL(-1), p=0.123 comparison to baseline) or 24 h (pneumonia: 31 (0-36), p=0.464; controls: 19 (0-43) pg x mL(-1), p=0.358). No changes of IL-1beta (baseline: pneumonia 0 (0-13); controls 1 (0-32) pg x mL(-1)) or IL-6 (baseline: pneumonia, 226 (9-4300); controls, 53 (0-346) pg x mL(-1)) were detected. No deterioration of clinical variables and no increase in systemic cytokine release has been observed after bronchoalveolar lavage, in critically ill patients. The potential cytokine increase is probably too small, in relation to the pre-existing inflammatory response, to yield clinical significance in this population otherwise antibiotic therapy may have been protective.

Aged↗
PubMed2000

Ventilator-associated pneumonia: incidence, risk factors, and microbiology.

Ventilator-associated pneumonia (VAP) is a pulmonary infection that occurs after at least 48 hours of mechanical ventilation (MV). The incidence depends on several factors, although the most important are those related to the host and duration of MV. VAP can be differentiated into early-onset (<5 days) and late-onset types (> or =5 days). The overall incidence of VAP varies between 9% and 70% (average, 20% to 25%), and the majority of episodes occur within the first 5 days. Risk factors for VAP include prolonged MV, older age, supine body position, and type of comorbidity. Oropharyngeal colonization appears to be a risk factor for early-onset pneumonia, whereas prolonged MV and antibiotic pretreatment, especially with broad-spectrum drugs, increase the risk for late-onset VAP Microaspiration of colonized oropharyngeal secretions is a major cause of early-onset VAP, most frequently caused by community-type pathogens. After 5 days of MV, pathological colonization with gram-negative bacteria may occur, and late-onset VAP is more likely to be attributable to this group of microorganism. Incidence, risk factors, and microbiology depend strongly on the time frame in which the episode develops. However, initial and pathological colonization during the intensive care unit stay can modify this concept.

Age Factors↗
PubMed2000

Sampling methods for ventilator-associated pneumonia: validation using different histologic and microbiological references.

OBJECTIVE: To validate sampling techniques (tracheobronchial aspirates, protected specimen brush, and bronchoalveolar lavage, both conventional and protected) for the detection of ventilator-associated pneumonia (VAP) and causative microorganisms according to different histologic and microbiological references. DESIGN: Immediate, multiple bilateral lung biopsy, postmortem study. SETTING: Respiratory intensive care unit of a 1,000-bed teaching hospital. PATIENTS: Twenty-five mechanically ventilated patients (>72 hrs) who died in our intensive care unit. MEASUREMENTS: Lung tissue histologic examination and quantitative cultures (16 specimens/patient). The following four references for the diagnostic techniques were used: histology of guided lung biopsy, histology of blind lung biopsy, combined guided and blind lung biopsy histology and microbiology of lung tissue, and microbiology of lung tissue. RESULTS: Sensitivities when histologic reference tests were used ranged from 16% to almost 40%, whereas specificity rates were always <80%. When we combined both lung histology of guided or blind specimens and microbiology of lung tissue, all diagnostic techniques achieved considerably higher but still limited diagnostic yields (sensitivity range 43% to 83%; specificity range 67% to 91%). Causative organisms were missed in a significant number of cases by all techniques (17% to 83%). CONCLUSIONS: The diagnostic performances of different diagnostic techniques strongly depend on the reference used. All techniques for detecting VAP are of limited value. Finding a balance between clinical judgment and microbiological results is crucial to appropriately manage patients with VAP.

Biopsy↗
PubMed2000

Comparison of systemic cytokine levels in patients with acute respiratory distress syndrome, severe pneumonia, and controls.

BACKGROUND: The inflammatory response has been widely investigated in patients with acute respiratory distress syndrome (ARDS) and pneumonia. Studies investigating the diagnostic values of serum cytokine levels have yielded conflicting results and only little information is available for the differential diagnosis between ARDS and pneumonia. METHODS: Clinical and physiological data, serum concentrations of tumour necrosis factor (TNF)-alpha, interleukin (IL)-1beta and IL-6, and quantitative cultures of lower respiratory tract specimens were obtained from 46 patients with ARDS and 20 with severe pneumonia within 24 hours of the onset of the disease and from 10 control subjects with no inflammatory lung disease. Cytokine concentrations were compared between groups and determinants in addition to the diagnosis were tested. RESULTS: Serum TNF-alpha levels were significantly higher in ARDS patients (67 (57) pg/ml) than in patients with severe pneumonia (35 (20) pg/ml; p = 0.031) or controls (17 (8) pg/ml; p = 0.007). For IL-1beta and IL-6 the observed differences were not statistically significant between patients with ARDS (IL-1beta: 34 (65) pg/ml; IL-6: 712 (1058) pg/ml), those with severe pneumonia (IL-1beta: 3 (4) pg/ml, p = 0.071; IL-6: 834 (1165) pg/ml, p = 1.0), and controls (IL-1beta: 6 (11) pg/ml, p = 0.359; IL-6: 94 (110) pg/ml, p = 0.262). TNF-alpha (standardised coefficient beta = 0.410, p<0.001) and IL-1beta (standardised coefficient beta = 0.311, p = 0.006) were most strongly associated with the degree of lung injury, even when the diagnostic group was included in the statistical model. CONCLUSIONS: Serum TNF-alpha levels were higher in patients with ARDS than in those with severe pneumonia or in control subjects. Multivariate results suggest that the levels of systemic TNF-alpha and IL-1beta reflect the severity of the lung injury rather than the diagnosis.

Biomarkers↗
PubMed2000

Treatment of severe nosocomial pneumonia: a prospective randomised comparison of intravenous ciprofloxacin with imipenem/cilastatin.

BACKGROUND: A prospective multicentre study was undertaken to compare the efficacy of intravenous ciprofloxacin or imipenem in the treatment of severe nosocomial pneumonia requiring mechanical ventilation. METHODS: Patients with a clinical suspicion of pneumonia were randomised to receive either ciprofloxacin (800-1200 mg/day) or imipenem (2-4 g/day) in doses adjusted for renal function and specimens of the lower respiratory tract were taken. Patients were included in the study when specimens showed significant growth for potentially pathogenic microorganisms in quantitative bacterial cultures (n = 75, ciprofloxacin 41/75 (55%); imipenem 34/75 (45%)). The clinical and bacteriological success rates were the primary and secondary efficacy variables. An intent-to-treat analysis was performed for all randomised patients who received at least one dose of the study medication (n = 149, ciprofloxacin 72/149 (48%), imipenem 77/149 (52%)). RESULTS: The success rates were generally good, but neither the clinical success rates (ciprofloxacin, 29/41 (71%), imipenem, 27/34 (79%); 95% CI -10.8 to 28.1; p = 0.435) nor the bacteriological response rate (ciprofloxacin, 20/41 (49%), imipenem, 17/34 (50%); 95% CI -21.5 to 23.9; p = 1.0) were significantly different between the study arms. Pseudomonas aeruginosa was recovered in 26/75 patients (35%) and clinical (ciprofloxacin, 10/14 (71%), imipenem, 8/12 (67%); 95% CI -40.4 to 30.9; p = 1.0) and bacteriological response rates (ciprofloxacin, 7/14 (50%), imipenem, 3/12 (25%), 95% CI -60.9 to 10.9, p = 0.247) were not significantly different in this subgroup of patients. Resistance of Pseudomonas aeruginosa developed in 5/26 cases (19%), 1/14 (7%) to ciprofloxacin and 4/12 (33%) to imipenem (p = 0.147), and the mortality was 12/75 (16%) with no difference between treatment groups (ciprofloxacin, 8/41(24%), imipenem 4/34 (17%); p = 0.362). The clinical response was evaluable in 109/149 patients (73%) in the intent-to-treat analysis and was successful in 74/109 patients (68%). The clinical response rates were also not significantly different in the intent-to-treat analysis (ciprofloxacin, 34/52 (65%), imipenem, 40/57 (70%); 95% CI -12.8 to 22.3; p = 0.746). CONCLUSIONS: Treatment with either ciprofloxacin or imipenem was effective in a selected group of patients with microbiologically confirmed, severe nosocomial pneumonia requiring mechanical ventilation. Although no differences between the study medication could be documented in this trial, smaller differences between treatment arms may have been missed because of sample size limitations.

Adult↗
PubMed2000

Capnometric recirculation gas tonometry and weaning from mechanical ventilation.

The aim of this study was to describe changes in regional intramucosal PCO(2) (Pr(CO(2)) measured with capnometric recirculation gas tonometry [CRGT]) in patients with acute respiratory failure, who proceed from mechanical ventilation to weaning. In addition, we compared the predictive power for the weaning outcome of CRGT measurements obtained during mechanical ventilation to the frequency/ tidal volume (f/VT) ratio. A total of 24 patients (31 weaning trials) were included in the study, but four of the 24 patients (17%) were excluded because of extubation failure. Of the remaining 27 weaning trials in 20 patients, 12 (44%) were unsuccessful. Changes observed in patients with weaning failure (increase in Pr(CO(2)) from 60.4 +/- 15.0 mm Hg in mechanical ventilation to 67.4 +/- 21.0 mm Hg, in weaning) were significantly different (p = 0.046) from those observed in patients with weaning success (fall in Pr(CO(2)) from 61.5 +/- 15.0 mm Hg in mechanical ventilation to 56.3 +/- 16.7 mm Hg in weaning). However, absolute values of Pr(CO(2)) were not significantly different between patients with weaning success and failure, neither during mechanical ventilation (success, 61.5 +/- 15.0 versus failure, 60.4 +/- 15.0 mm Hg, p = 0.848) nor during weaning (success, 56.3 +/- 16.7 versus failure, 67.4 +/- 21.0 mm Hg, p = 0.135). The best single predictor for weaning outcome was the f/VT ratio measured early during weaning (area under the curve: 0.844 +/- 0.081; adjusted odds ratio for threshold value </= 105: 42.0, 95% CI 3.8 to 469.1, p = 0.002). CRGT could confirm a significant increase in Pr(CO(2)) during weaning in patients who finally failed the weaning trial. However, differences between patients with weaning success and failure were small and CRGT did not replace or improve the predictive power of the f/VT ratio for weaning outcome.

Acute Disease↗
PubMed2000

Diagnosis of pneumonia and monitoring of infection eradication.

Pneumonia can be classified as community-acquired (CAP) or hospital-acquired (nosocomial). Both are frequent infections that demand a great amount of medical resources. The diagnosis of CAP is based on clinical signs and the presence of a pulmonary infiltrate visible on chest radiograph. For practical purposes, CAP has been classified as typical, with an acute onset in which the most representative microorganism is Streptococccus pneumoniae, and atypical, with a subacute onset (Mycoplasma pneumoniae). Nevertheless, so far no studies have clearly demonstrated the utility of this classification in predicting the aetiology. Guidelines on CAP recommend associating the aetiology of CAP with comorbidity, age and severity. The microbiological diagnosis relies mainly on Gram stain and sputum culture, but this technique has disadvantages such as frequent contamination of the sample with oropharyngeal commensal flora, frequent sterile cultures associated with previous antibiotic treatment, and the fact that approximately 40% of patients are not able to expectorate. Other diagnostic techniques such as blood cultures, serological tests and fibreoptic bronchoscopy must be reserved for patients who are hospitalised, especially if they need admission to an intensive care unit. Compared with CAP, nosocomial pneumonia has major diagnostic problems due to the presence of other diseases able to mimic pneumonia and frequent bacterial colonisation of the lower respiratory tract. Most of the diagnostic techniques produce a high percentage of false-negative and false-positive results. This is especially true for ventilator-associated pneumonia. There is controversy over using a comprehensive aetiological work-up based on bronchoscopic techniques or only on quantitative culture of endotracheal aspiration. By contrast, there is consensus about the importance of the adequacy of empirical antibiotic treatment, since mortality rates are higher in patients who are inadequately treated. Once treatment of pneumonia has begun, it must be maintained for 48 to 72 hours because this is the minimum time to evaluate a clinical response. Antibacterial agents have to be adjusted according to microbiological findings. In nonresponding patients, pneumonia-related complications and the presence of multiresistant micro-organisms or non-covered pathogens must be ruled out.

Anti-Bacterial Agents↗
PubMed1999

Supine body position as a risk factor for nosocomial pneumonia in mechanically ventilated patients: a randomised trial.

BACKGROUND: Risk factors for nosocomial pneumonia, such as gastro-oesophageal reflux and subsequent aspiration, can be reduced by semirecumbent body position in intensive-care patients. The objective of this study was to assess whether the incidence of nosocomial pneumonia can also be reduced by this measure. METHODS: This trial was stopped after the planned interim analysis. 86 intubated and mechanically ventilated patients of one medical and one respiratory intensive-care unit at a tertiary-care university hospital were randomly assigned to semirecumbent (n=39) or supine (n=47) body position. The frequency of clinically suspected and microbiologically confirmed nosocomial pneumonia (clinical plus quantitative bacteriological criteria) was assessed in both groups. Body position was analysed together with known risk factors for nosocomial pneumonia. FINDINGS: The frequency of clinically suspected nosocomial pneumonia was lower in the semirecumbent group than in the supine group (three of 39 [8%] vs 16 of 47 [34%]; 95% CI for difference 10.0-42.0, p=0.003). This was also true for microbiologically confirmed pneumonia (semirecumbent 2/39 [5%] vs supine 11/47 [23%]; 4.2-31.8, p=0.018). Supine body position (odds ratio 6.8 [1.7-26.7], p=0.006) and enteral nutrition (5.7 [1.5-22.8], p=0.013) were independent risk factors for nosocomial pneumonia and the frequency was highest for patients receiving enteral nutrition in the supine body position (14/28, 50%). Mechanical ventilation for 7 days or more (10.9 [3.0-40.4], p=0.001) and a Glasgow coma scale score of less than 9 were additional risk factors. INTERPRETATION: The semirecumbent body position reduces frequency and risk of nosocomial pneumonia, especially in patients who receive enteral nutrition. The risk of nosocomial pneumonia is increased by long-duration mechanical ventilation and decreased consciousness.

Aged↗
PubMed1999

Effect of nasogastric tube size on gastroesophageal reflux and microaspiration in intubated patients.

BACKGROUND: Little evidence exists to support the theory that small-bore nasogastric tubes prevent gastroesophageal reflux and microaspiration in intubated patients. OBJECTIVE: To determine whether gastroesophageal reflux and microaspiration in intubated patients can be reduced by the use of a small-bore nasogastric tube. DESIGN: Randomized, two-period crossover trial. SETTING: Respiratory intensive care unit of a university hospital. PATIENTS: 17 patients intubated for more than 72 hours. INTERVENTIONS: Radioactive technetium colloid was instilled in each patient's stomach. Patients were studied with two nasogastric tubes (one tube with a 6.0-mm external bore and one tube with a 2.85-mm external bore) in randomized order; measurements of radioactive counts with the alternate size of nasogastric tube were repeated 72 hours after original measurements were taken. Sequential samples of serum, gastric juice, and pharyngeal and tracheal secretions were obtained. MEASUREMENTS: Comparison of the time course of radioactive counting in all samples (obtained during the use of each nasogastric tube size in each patient). RESULTS: The mean radioactive count of pharyngeal aspirates (P = 0.004) was greater than the baseline count at all time points, as was the cumulative radioactive count of pharyngeal aspirates 17 hours after the first dose of technetium colloid was administered (P = 0.001); however, the count of tracheal aspirates was never greater than the count at baseline. No differences were found between tube types when the time course and cumulative counts of pharyngeal and tracheal samples were compared. CONCLUSION: Small-bore nasogastric tubes in intubated patients do not reduce gastroesophageal reflux or microaspiration.

Cross-Over Studies↗
PubMed1999

Forced expiratory wheezes in a patient with dynamic expiratory narrowing of central airways and an oscillating pattern of the flow-volume curve.

Forced expiratory wheezes (FEW) are common and the pathogenesis of this phenomenon might involve fluttering of the airways, but this theory has not been confirmed in patients. We report a case of a patient with FEW and a normal FEV1 that showed a bronchoscopically confirmed collapse of the trachea and main stem bronchi during forced expiration. Superimposed to the flow-volume curve was an oscillating pattern with a frequency that corresponded well with the wheeze generated during forced expiration. The oscillating pattern in the flow-volume curve and the collapse of the major airways supports the theory of wheezes generated by fluttering airways during forced expiration. Although FEW may be found also in healthy subjects, flow limitation is essential for the generation of FEW. The inclusion of a forced expiratory maneuver in the clinical examination might therefore be helpful in guiding the diagnosis towards airways obstruction.

Airway Resistance↗
PubMed1998

[Effect of salmeterol in obstructive sleep apnea syndrome].

The effect of inhaled long-acting beta 2-agonists on obstructive sleep apnoea syndrome (OSAS) is unknown, though from the pharmacological point of view both therapeutic and adverse effects might be discussed. The purpose of this study was to obtain data on the efficacy and safety of Salmeterol in patients with OSAS. In a randomised, double-blind, placebo-controlled, crossover study effects of Salmeterol were investigated in 20 patients with OSAS: 4 female, 16 male; age 53.0 +/- 7.8 years, body mass index (BMI) 28.0 +/- 3.0 kg.m-2; apnoea hypopnoea index (AHI) 35.6 +/- 17.8 h-1. Patients with asthma, chronic obstructive pulmonary disease (COPD), and left heart failure were excluded. Placebo or verum (50 micrograms Salmeterol) were administered at 7 p.m. by metered dose inhaler and spacer device. All patients underwent full polysomnography during baseline, placebo, and verum night. Statistical analysis was performed by Student's t-test (p < 0.05). Between placebo and verum there were no differences in total sleep time, sleep stages, apnoea index (AI), AHI, and nadir SaO2. There was, however, a significant deterioration of mean SaO2 (placebo 93.1 +/- 2.0 vs Salmeterol 92.5 +/- 2.2%) and of relative time spent with SaO2 < or = 90% (placebo 13.1 +/- 14.5 vs Salmeterol 19.5 +/- 20.8%), as well as a significant increase in heart rate (placebo 63.1 +/- 9.2 vs Salmeterol 65.6 +/- 9.3 h-1). Thus, in patients with OSAS Salmeterol had no adverse effect on quality of sleep, AI or AHI. The slight increase in heart rate and the deterioration of oxygen saturation are clinically irrelevant. The latter might be due to ventilation-perfusion-mismatch. This study demonstrates that Salmeterol has no influence on obstructive sleep apnoea and hypopnoea, but on the other hand provides an acceptable safety profile in OSAS. This might be of special importance in patients suffering from both OSAS and obstructive airway disease.

Adrenergic beta-Agonists↗
PubMed1998

[Submaximal spiroergometric stress study in patients with mixed dust pneumoconiosis].

Disabilities of patients with coal-workers' pneumoconiosis (CWP) are currently estimated by changes in lung function at rest and the degree of dust equivalents in chest x-ray (ILO-classification 1980). Functional disturbances during exercise are not taken into consideration on a regular basis. We assumed that standardised sub-maximal exercise tests might be useful even in disabled patients to give additional information on functional disabilities of patients with CWP. The impact of low-grade anthracosilicosis on ventilation and gas exchange during exercise was assessed in 20 patients (all male, age 64.55 +/- 3.78 years) and 24 healthy volunteers (all male, age 58.13 +/- 4.68 years, never dust exposed). Data were also analysed according to ILO classification subgroups (group 1: ILO-classification 1/0 to 1/2, n = 11; group 2: ILO-classification 2/1 to 2/2, n = 9). Heart rate (HR), minute ventilation (VE), ventilatory equivalent for O2 (VE/VO2), ventilatory equivalent for CO2 (VE/VCO2), O2 uptake (VO2)CO2 output (VCO2), end-tidal oxygen partial pressure (PetO2), end-tidal carbon dioxide partial pressure (petCO2) and estimated dead space to tidal volume ratio (VD/VT) were determined breath-by-breath during a 50 watts constant work load protocol on an exercise bicycle. The VE/VO2 (patients: 32.9 +/- 4.2; controls: 25.7 +/- 2.9; p < 0.001), the VE/CO2 (patients: 39.4 +/- 4.6; controls; 31.0 +/- 3.9), the VE (patients: 30.1 +/- 5.6, controls: 23.5 +/- 3.0; p < 0.001) and the PetO2 (patients 115.6 +/- 4.8; controls: 99.1 +/- 27.4; p < 0.05) at an exercise of 50 watts were significantly higher in the patients' group, the PetCO2 (patients: 38.4 +/- 4.5; controls: 44.0 +/- 4.1) were significantly lower in the patients' group. The comparison of patients subgroups did not reveal any significant differences between group 1 and group 2. A higher VE/VO2 during 50 watts of exercise is attributable to an increased ventilation/perfusion mismatch. There was no correlation between the radiological grade of the CWP (ILO classification) and the ventilation and gas exchange during exercise. We conclude that a sub-maximal spiroergometry with a 50 watts constant work load might serve as a sensitive and easy to apply procedure add information about the functional impairment in CWP. The exercise test should be included in the evaluation for disability benefits.

Adult↗
PubMed1997

[Stress test blood gas analysis in chronic obstructive lung diseases].

This study was conducted to investigate the clinical value of blood gas analysis during exercise in patients with COPD and healthy controls using the new criteria of the Deutsche Gesellschaft für Pneumologie (DGP) for performance and interpretation of blood gas analysis during exercise. A total of 64 patients with COPD (age: 63.7 +/- 10.1 years) and 35 healthy controls (age: 35.0 +/- 14.3 years) exercised on a bicycle ergometer to their submaximal capacity under steady state conditions (patients: 44.4 +/- 24.6 watt vs. 102.4 +/- 32.1 watt; p < 0.01). A pathological response for PaO2 occurred in 3 of 35 controls (8.6%) and 14 of 64 patients (21.9%; p < 0.01). A decrease in PaO2 yielded a sensitivity of 28% and a specificity of 92% in respect of patients with emphysema. Significant associations of lung function parameters at rest and blood gases under exercise were found by linear regression analysis (airway resistance (Rt): beta = -0.48; p < 0.001) and PaCO2 (FEV1: beta = -0.27; p < 0.05). This study demonstrates that in patients with COPD parameters of lung function and blood gas analysis at rest are already good predictors of gas exchange under exercise conditions. In individual cases, however, prediction may not be possible. This underlines the importance of the exercise test to investigate gas exchange under diagnostic (i.e. dyspnoea, medical opinion) and therapeutic aspects (i.e. therapy control). For COPD patients, the rule of the DGP yielded a poor sensitivity, but an excellent specificity in the diagnosis of emphysema, which yields confirmation of the diagnosis only in conjunction with, and complementary to, other methods.

Adult↗