One-year follow-up of patients of the ongoing Dutch Q fever outbreak: clinical, serological and echocardiographic findings.

PURPOSE: In 2007, a large goat-farming-associated Q fever outbreak occurred in the Netherlands. Data on the clinical outcome of Dutch Q fever patients are lacking. The current advocated follow-up strategy includes serological follow-up to detect evolution to chronic disease and cardiac screening at baseline to identify and prophylactically treat Q fever patients in case of valvulopathy. However, serological follow-up using commercially available tests is complicated by the lack of validated cut-off values. Furthermore, cardiac screening in the setting of a large outbreak has not been implemented previously. Therefore, we report here the clinical outcome, serological follow-up and cardiac screening data of the Q fever patients of the current ongoing outbreak. METHODS: The implementation of a protocol including clinical and serological follow-up at baseline and 3, 6 and 12 months after acute Q fever and screening echocardiography at baseline. RESULTS: Eighty-five patients with acute Q fever were identified (male 62%, female 38%). An aspecific, flu-like illness was the most common clinical presentation. Persistent symptoms after acute Q fever were reported by 59% of patients at 6 months and 30% at 12 months follow-up. We observed a typical serological response to Coxiella burnetii infection in both anti-phase I and anti-phase II IgG antibodies, with an increase in antibody titres up to 3 months and a subsequent decrease in the following 9 months. Screening echocardiography was available for 66 (78%) out of 85 Q fever patients. Cardiac valvulopathy was present in 39 (59%) patients. None of the 85 patients developed chronic Q fever. CONCLUSIONS: Clinical, serological and echocardiographic data of the current ongoing Dutch Q fever outbreak cohort are presented. Screening echocardiography is no longer part of the standard work-up of Q fever patients in the Netherlands.

Detailed analysis of health status of Q fever patients 1 year after the first Dutch outbreak: a case-control study.

BACKGROUND: Q fever is a zoonosis caused by the obligate intracellular bacterium Coxiella burnetii. The two long-term complications, after primary infection, are chronic Q fever in ∼1% of patients, and a chronic fatigue syndrome in 10-20%. However, the existence of a protracted decreased health status after Q fever remains controversial. AIM: To determine the health status of the patients of the Q fever outbreak in The Netherlands in 2007, 1 year after primary infection. DESIGN: Cross-sectional case-control study. METHODS: Health status of the patients from the 2007 Dutch Q fever outbreak was compared to age-, sex- and geographically matched and Q fever seronegative controls. Health status of both patients and controls was assessed with the Nijmegen Clinical Screening Instrument (NCSI). RESULTS: Fifty-four Q fever patients provided 34 years of age- and sex-matched controls from the same neighbourhood. Eleven controls had positive Q fever serology and were excluded. Q fever patients had significantly more problems on the subdomains of symptoms and functional impairment. Overall quality of life was decreased in both patients and controls, 59% vs. 39%, respectively, ns). Severe fatigue levels were present in 52% of patients vs. 26% in controls (P < 0.05). CONCLUSION: These data support a sustained decrease in many aspects of health status in Q fever patients in The Netherlands, 1 year after primary infection.

Procalcitonin kinetics in Legionella pneumophila pneumonia.

Little is known about procalcitonin (PCT) levels in patients with community-acquired pneumonia (CAP) caused by Legionella pneumophila. The aim of the present study was to investigate this infection marker in patients admitted with L. pneumophila pneumonia in relation to conventional inflammatory parameters, severity of pneumonia upon admission and clinical outcome. Eighteen patients admitted with CAP caused by L. pneumophila serogroup 1 were retrospectively examined. PCT measurements were carried out during the first week of admission in addition to measurements of C-reactive protein (CRP), white blood cell (WBC) count and registration of severity of pneumonia upon admission (CURB-65 score). The mean PCT level upon admission in patients with L. pneumophila pneumonia was 13.5 ng/mL (range 0.3-55.7 ng/mL). Mean CRP level was 397 mg/L (range 167-595 mg/L) and mean WBC count 11.7 x 10(9)/L (range 4.5-20.4 x 10(9)/L). Initial high PCT levels were indicative of more severe disease as reflected by prolonged intensive care unit (ICU) stay and/or in-hospital death. Patients admitted to the ICU showed significantly higher PCT levels compared with the remaining patients [26.7 ng/mL (range 4.6-55.7 ng/mL) vs. 6.9 ng/mL (range 0.3-29.3 ng/mL); p 0.019]. There was a significant correlation between Acute Physiology and Chronic Health Evaluation-II scores upon ICU admission and initial PCT levels upon hospital admission (r = 0.86; p 0.027). Persistently increased PCT levels during treatment were indicative of unfavourable clinical outcome. Conventional inflammatory parameters (CRP and WBC) and the CURB-65 score lacked this discriminatory capacity in our study population. PCT may therefore be a valuable tool in the initial clinical assessment and follow-up of patients with L. pneumophila pneumonia.

Hepatitis B virus infected health care workers in The Netherlands, 2000-2008.

In response to the confirmed transmission of hepatitis B virus (HBV) from a surgeon to several patients in the Netherlands, a 'Committee for Prevention of Iatrogenic Hepatitis B' was established in 2000. During the years 2000-2008, the committee reviewed 99 cases of HBV-infected health care workers. Fifty of them were found to perform exposure prone procedures (EPPs). Because of high levels of HBV DNA (>100,000 copies/ml), a ban on performing EPPs was applied in 11/50 cases; 25/50 low-viremic health care workers were allowed to continue EPPs while their HBV load was being monitored; and 14/50 cases had stopped working or changed profession. In five restricted workers who started oral antiviral treatment, HBV replication was persistently suppressed, enabling the ban on EPPs to be lifted. Throughout the European Union different levels of HBV viremia have been chosen, above which health care workers are not allowed to perform EPPs. It remains unknown how this affects the safety of patients. Application in the Netherlands of a European or a British guideline would have, respectively, doubled or tripled the number of restricted health care workers.

Specific and sensitive detection of Neisseria gonorrhoeae in clinical specimens by real-time PCR.

Early diagnosis of Neisseria gonorrhoeae infections is important with regard to patients' health and infectivity. We report the development of a specific and sensitive TaqMan assay for the detection of N. gonorrhoeae in clinical samples. The target sequence is a 76-bp fragment of the 5' untranslated region of the opa genes that encode opacity proteins. A panel of 448 well-defined N. gonorrhoeae isolates was used to evaluate and optimize the assay. The method employs two minor-groove binding probes, one of them recognizing a newly identified sequence in the opa genes. Testing a large panel of related and unrelated microorganisms revealed that other Neisseria strains and other microorganisms tested negative in the opa test. With a lower detection limit of one genome per reaction, the opa test appeared more sensitive than both the COBAS AMPLICOR (Roche Diagnostics Nederland BV, Almere, The Netherlands) and a LightCycler 16S rRNA test. Analysis of a panel of 122 COBAS AMPLICOR-positive samples revealed that 68% were negative in both the 16S rRNA test and the opa assay (confirming that the COBAS AMPLICOR test produces false positives), while 30% were positive in both assays. Three samples were opa positive and 16S rRNA negative, which may be due to the higher sensitivity of the opa assay. We conclude that the opa gene-based real-time amplification assay offers a sensitive, specific, semiquantitative, and reliable assay suitable for the detection of N. gonorrhoeae in clinical specimens and/or for confirmation of less specific tests.

Mycobacterium xenopi infection in an immunosuppressed patient with Crohn's disease.

A 48 year old patient with active Crohn's disease presented with bilateral nodules over his lungs resembling malignant metastasis. Bronchoscopic and pathological examination of the airways and sputum did not show any malignancy. After 6 weeks Mycobacterium xenopi was cultured from his bronchial washings while all other cultures remained negative. Treatment was started with rifampicin, ethambutol, and clarithromycin and, after 9 months of treatment, there was an almost complete resolution of his chest radiograph.

Conjunctival and corneal colonization by Pseudomonas aeruginosa in mechanically ventilated patients. A prospective study.

In patients on mechanical ventilation the eyes may be colonized with P. aeruginosa. This study was designed to establish an association between endotracheal suctioning and this colonization. During the study period from January to August 1996, ten out of twenty-eight (36%) patients who were mechanically ventilated for than 3 days developed colonization of the respiratory tract with P. aeruginosa. In seven out of these ten patients (70%) conjunctival colonization with P. aeruginosa could be established. Subsequently three patients (11%) developed a clinical eye infection. In all patients the eye on the side corresponding to the position of the ventilator, the suction device and the location of the nurse during suctioning procedures, was colonized first. Contamination of the conjunctiva probably occurs by aerosol exposure during disconnection of the intubation tube from the ventilator for tracheal suctioning. Patients on mechanical ventilation may have an increased risk for eye infections.

Candida tropicalis arthritis in a patient with acute myeloid leukemia successfully treated with fluconazole: case report and review of the literature.

The case of a 77-year-old woman with acute myeloid leukemia who developed Candida tropicalis septic arthritis of the knee after remission-inducing chemotherapy is reported. A literature review of C. tropicalis non-prosthetic arthritis is included. The isolate was susceptible to fluconazole (MIC 0.25 mg/l). She was treated with fluconazole (400 mg orally) and frequent relieving synovial aspirations. After 1 month of antifungal therapy the synovial fluid became culture negative. Fluconazole concentration in the synovial fluid and serum were 20 mg/l and 19.4 mg/l, respectively. The patient was treated for a total of 7 months and made a full recovery. This is the first report of the successful use of fluconazole in the treatment of septic arthritis due to C. tropicalis.

Expression of surface markers on alveolar macrophages from symptomatic patients with HIV infection as detected by flow cytometry.

Alveolar macrophages (AMs) harvested from 32 HIV-infected patients with respiratory problems (opportunistic pulmonary infections, n = 12; other lung disease, n = 20) and 13 healthy controls were stained with a panel of 15 monoclonal antibodies directed against surface antigens implicated in cell function. Antigen expression was quantified by flow cytometry and expressed as relative linear median fluorescence intensity (RLMFI). On AMs of patients, as compared with controls, there was a significant enhancement of HLA DP (12.1 +/- 1.5 vs 6.5 +/- 0.9, p = 0.01, M +/- SEM, RLMFI units), CD11b (3.4 +/- 0.5 vs 1.7 +/- 0.4, p = 0.014), CD11c (8.9 +/- 1.0 vs 4.8 +/- 0.8, p = 0.0046), CD14 (2.1 +/- 0.3 vs 1.0 +/- 0.2, p = 0.0009), and CD33 (1.7 +/- 0.1 vs 1.0 +/- 0.2, p = 0.0093). No significant differences could be established for HLA-DR (36.9 +/- 5.8 vs 30.9 +/- 7.5, NS), HLA-DQ (3.4 +/- 0.3 vs 3.1 +/- 0.6, NS), CD54 (1.9 +/- 0.3 vs 1.2 +/- 0.1, NS), CD13 (2.5 +/- 0.6 vs 1.5 +/- 0.3, NS), CD36 (1.4 +/- 0.2 vs 0.9 +/- 0.3, NS), CD71 (10.3 +/- 1.9 vs 8.9 +/- 1.8, NS), CD25 (0.8 +/- 0.0 vs 0.9 +/- 0.1, NS), 27E10 (1.1 +/- 0.1 vs 0.8 +/- 0.3, NS), RM3/1 (1.9 +/- 0.4 vs 1.5 +/- 0.4, NS), and CD4 (1.5 +/- 0.3 vs 1.0 +/- 0.0, NS). The expression of CD14 and CD11b, but not of HLA class II antigens and CD71, was increased in the smaller cell population compared with the larger, thus suggesting monocyte recruitment. The increased expression of HLA-DP, CD11c, CD14, and CD33 on the patients' AMs was independent of smoking habits. The degree of immunodeficiency as indicated by the absolute peripheral CD4 count, the character of HIV-related pulmonary disease, and the prophylactic use of pentamidine or zidovudine did not significantly modify the antigen expression pattern. It is concluded that HIV infection may lead, most probably indirectly, to enhanced expression of surface antigens by local upregulation and/or recruitment of monocytes from the peripheral circulation. The functional significance of enhanced marker expression requires further clarification.

[Ergospirometric studies of normal probands for an unsteady-state increment test program]. / Ergospirometrische Normalkollektivuntersuchungen für ein Unsteady-state-Stufentestprogramm.

One-hundred-sixteen healthy subjects (60 female and 56 male) with normal height (L) and weight (w) were selected to provide an even distribution of age (A, 20-70 years). All underwent an unsteady state cycle ergometer test with work increments of 20 watts each minute to exhaustion. A commercially available exercise testing system (EOS SPRINT, Jäger Corp., FRG) with gas analysis from a mixing chamber was used to study oxygen uptake (VO2), carbon dioxide output (VCO2), heart rate (HR), tidal volume (VT), breathing frequency (BR) and arterial oxygen tension (PO2) with special regard to the ventilatory anaerobic threshold (VAT) and maximum power output. For all parameters multiple regression equations were determined. Furthermore, heart rate reserve (HR-reserve), breathing reserve (VE-reserve), O2-pulse (VO2/HR), the dead space/tidal volume ratio (VD/VT) and the alveolar-arterial PO2-difference (AaDO2) were calculated. Day-to-day reproducibility was proven in 21 subjects. VO2max in females was 1584 +/- 300 ml/min (VO2max = -17 A + 10 L + 10 G + 58, r = 0.75, p < 0.0001), VO2AT 957 +/- 159 ml/min (VO2AT = 0.35 VO2max + 0.40 l/min, r = 0.77, p < 0.0001). The ratio VO2AT/VO2max was 50 +/- 7%. In male, VO2max was 2452 +/- 529 ml/min (VO2max = -23 A + 23 L + 9.5 G - 1395, r = 0.78, p < 0.0001), VO2AT 1209 +/- 213 ml/min (VO2AT = 0.29 VO2max + 0.51 l/min, r = 0.71, p < 0.0001), and VO2AT/VO2max 62 +/- 9%.(ABSTRACT TRUNCATED AT 250 WORDS)

Impairment of exercise capacity in various groups of HIV-infected patients.

It is known that pulmonary function is impaired during the course of HIV infection even in early stages. In order to estimate the resulting reduction of exercise capacity, different groups of HIV patients were investigated. Group 1 consisted of 20 patients without a history of respiratory disease and without actual lung disease, group 2 of 18 patients with a former episode of Pneumocystis carinii pneumonia (PCP) without actual lung disease, and group III of 37 patients with different broncho-pulmonary complications including PCP. 20 normal subjects served as controls. Spirometry, diffusing capacity (DLCO) and exercise tests including arterial blood gas analysis (BGA) were performed in patients and controls. Compared to the controls group 1 patients revealed a decreased DLCO (TCO: 83 +/- 15 vs. 67 +/- 15% pred.norm.) while spirometric data were normal. VO2 and O2 pulse at the anaerobic threshold (17.7 +/- 5.1 vs. 14.3 +/- 2.6 ml/kg.min and 10.8 +/- 4.0 vs. 8.6 +/- 1.9 ml/beat, respectively) and maximum exercise (33.9 +/- 9.7 vs. 22.1 +/- 3.4 ml/kg.min and 15.0 +/- 5.0 vs. 11.3 +/- 2.5, respectively) were decreased, whereas AaDO2, VD/VT, and the HR/VO2 slope were normal. The reserves of heart rate and ventilation were high. Except for a reduced maximum work rate in group 1, no significant difference was found between groups 1 and 2. Group 3 patients differed most from groups 1 and 2 with respect to spirometry, DLCO and AaDO2, rather than VO2.(ABSTRACT TRUNCATED AT 250 WORDS)

[Non-invasive measurement of stroke volume in steady-state and unsteady-state workload with CO2 rebreathing]. / Nichtinvasive Messung des Herzzeitvolumens während Steady-State- und Unsteady-state-Belastungen mittels CO2-Rückatmung.

During steady-state exercise the noninvasive measurement of cardiac output using CO2-rebreathing has been found to be reliable and reproducible. In contrast, reliability of cardiac output measurement during unsteady state exercise is unclear. The ability to determine cardiac output (CO) noninvasively during steady state and unsteady state exercise was assessed in nine healthy students aged 25.7 +/- 7.4 years. Two cycle ergometer exercise tests were performed, one maximal unsteady state test with 25 watts increment of workload per minute, and also one steady state test at 25, 50, and 75 percent of max. VO2. CO was measured using the equilibrium CO2-rebreathing technique during unloaded cycling in both tests, at 75 and 150 watts in the unsteady state test and at all workloads during steady state exercise. Mean max. VO2 was 31.4 +/- 5.9 ml/kg/min and mean VO2 at the anaerobic threshold 24.5 +/- 7.2 ml/kg/min, respectively. During unsteady state exercise the CO2/workload slope was linear (r = 0.973), as with steady state exercise (r = 0.976). There was no difference concerning the slopes of both curves, but the elevation of VO2 with unsteady state exercise was lower, compared to steady state (p < 0.005). The relationships of CO/VO2 during unsteady and steady state exercise were best expressed by linear equations: CO = 7.49 x VO2 + 2.35 (r = 0.866) and CO = 8.24 x VO2 + 1.4 (r = 0.852), respectively. Similar to VO2/workload, both regressions did not have different slopes, but did have different elevations (p < 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

[Cardiopulmonary capacity in patients with coronary heart disease]. / Kardiopulmonale Leistungsfähigkeit bei Patienten mit koronarer Herzkrankheit.

Cardiopulmonary exercise testing (CPX) allows a non-invasive control of the cardiopulmonary exercise capacity. In this study, we wanted to investigate if the CPX can be securely, practicably, and accurately performed in patients with invasively documented coronary heart disease (CHD). Furthermore, we wanted to find out the clinical value of CPX in CHD diagnosis. The CPX measurements (symptom-limited; ramp program with 20 Watts increase/min; semi-supine position; continuous registration of the cardio-circulatory parameters (HR, RR, ECG), of the gas exchange parameters (O2, CO2) and of the ventilation) in 101 patients have shown that CPX is secure, accurate, and practicable. The day-to-day reproducibility is high (r > 0.8). The respiratory anaerobic threshold can be manually evaluated by means of the PET O2 criterion in 95% of the cases. The CCS-classification of angina pectoris could not accurately describe the cardiopulmonary exercise capacity as compared to the Weber-classification. The disadvantage of the Weber-classification is that it does not respect the age-, sex- and weight-dependent differences of the normal values. Our own data and results from the literature demonstrate that the anaerobic threshold, the maximum VO2 and the maximum O2-pulse are the more reduced the more coronary arteries are involved, the more reduced the left ventricular function is. But, nevertheless, the range of values shows large overlaps so that an exact differentiation, based upon these parameters, is not possible. Patients with similar functional results or degree of reduced exercise capacity have different morphological alterations. Most patients demonstrated typical ischemic cascade with anaerobic threshold, ST-segment alterations, angina pectoris and, finally, reduced max. VO2. In conclusion, CPX does not replace the traditional methods of non-invasive and invasive ischemia detection, but enables secure, practicable, and accurate measurements of the individual cardiopulmonary exercise capacity and the interaction between muscles, heart, circulation, and lungs. Possibly, CPX can be used in the near future for identifying CHD patients with low, medium or high risk.

[Methodologic aspects of modern, computerized ergospirometry (CPX): ramp program, constant workload test and CO2 rebreathing method]. / Methodische Aspekte der modernen, computerisierten Ergospirometrie (CPX): Rampenprogramm, konstanter Belastungstest und CO2-Rückatmungsmethode.

The cardiopulmonary exercise testing (CPX) is a non-invasive method for the evaluation of the cardiopulmonary exercise capacity. Based upon the recent technical progress in gas analysers and personal computers today it is possible to perform CPX with acceptable time consumption, high practicability and high reproducibility of the results in many clinical areas. CPX is realized on a bike or on a treadmill. In bicycle CPX a ramp program (increase of x watts per minute) or a constant workload test (p.e. with 75% of the watts at anaerobic threshold) are performed. Furthermore, an estimation of the cardiac output using CO2-rebreathing method can be realized during a ramp program or a constant workload test. In this paper, also the CPX parameters of the ramp program, the constant workload test and the CO2-rebreathing method are defined and explained. The normal values of CPX are dependent of age, sex, body weight and exercise program. This should be kept in mind in interpreting the measured CPX data. Additionally, the performance of a routine CPX will be reported. Furthermore, the accuracy of the CPX parameters and the potential influences on the data will be discussed. Finally, problems during measurements and their analysis will be clarified.

Air trapping and cardiopulmonary exercise testing in patients with mild to moderate bronchial obstruction: clinical role of trapped gas measurements.

UNLABELLED: In 14 patients with obstructive airways disease (7 atopic asthmatics, 7 COPD pts with stable disease, FEV1 < 65% pred., 11 m, 3 f, age 50.9 +/- 17.2 y) the effect of a beta mimetic agent on physical performance was studied. PROTOCOL: Inhalation of 2.5 ml normal saline (P) or salbutamol 0.1% (S) in double-blind random order on 2 successive days. Spirometry, body-plethysmography, single-breath helium dilution at rest. Spiroergometry with incremental workload to tolerance. The volume of trapped gas (D) was derived from: TLC Body-TLC Helium Single Breath. RESULTS: Base line values revealed mild to moderate airways obstruction (FEV1 2.04 +/- 0.81 L, FEV1/VC 60.2 +/- 8.5%). Subsequent to inhaling S FEV1 increased significant by 20% to 2.38 +/- 0.87 L. There was a concomitant substantial improvement of VC (3.37 +/- 1.09 L to 3.60 +/- 0.93 L). Rs declined sign. (2.37 +/- 1.43 to 1.69 +/- 0.8 kPa*s), and so did D (1.15 +/- 0.73 L to 0.55 +/- 0.89 L = -20% from base line). Despite clear-cut bronchodilation exercise performance did not improve in response to S (114.6 +/- 49.3 vs 112.5 +/- 50.0 Watt max, ns). Base line max. VO2 (19.78 +/- 6.36 ml/min/kg) and VO2 at anaerobic threshold (13.29 +/- 3.21 ml/min/kg) suggested only minimal impairment of physical performance. S induced a small but significant decrease in max. VO2 (19.78 +/- 6.36 to 18.43 +/- 6.27 ml/min/kg, p < 0.025). Gas exchange (derived from AaDO2) was impaired at rest (30.18 +/- 10.4 mmHg) and during exercise (28.07 +/- 13.03 mmHg).(ABSTRACT TRUNCATED AT 250 WORDS)

[Predictive value of ergospirometry in preoperative assessment of risk factors before lung resections]. / Prädiktiver Wert der Spiroergometrie in der präoperativen Abschätzung von Risikopatienten vor Lungenresektionen.

Surgical resection for lung cancer provides the only real chance for cure. However, there is a high risk of postoperative complications including death for patients with pulmonary dysfunction. Therefore preoperative identification of patients at risk is necessary. Apart from history and physical examination three tests are currently used: 1. resting lung function (RFL), 2. invasive measurement of pulmonary vascular resistance (PVR) and 3. exercise testing with measurement of oxygen consumption (VO2). Main studies in the literature report the probability of abnormal tests for prediction of pulmonary complications (positive predictive value) and the probability of normal tests for prediction of uneventful outcome (negative predictive value) as follows: [table: see text] In conclusion, the "ideal" test predictive for morbidity and mortality after lung resection has not been found. The positive predictive values of RLF and PVR are disappointing, while the negative predictive values are acceptable. Measurement of VO2 is simple, noninvasive and might predict survivable morbidity, as suggested in the literature. Obviously, additional studies are necessary.

[Methodologic and clinical comparison of four different ergospirometry systems]. / Methodischer und klinischer Vergleich von vier verschiedenen Ergospirometriesystemen.

The clinician who uses cardio-pulmonary exercise testing (CPX) systems relies on the technical informations from the device producers. In this paper, the practicability, the accuracy and the safety of four different, available CPX systems are compared in the clinical area, using clinically orientated criteria. The exercise tests were performed in healthy subjects, in patients with cardiac and/or pulmonary disease as well as in young or old people. The comparison study showed, that there were partially large differences in device design and measurement accuracy. Furthermore, our investigation demonstrated that beneath repetitive calibrations of the CPX systems a frequent validation of the devices by means of a metabolic simulator is necessary. Problems in calibration can be caused by an inadequate performance or by unclean calibration gases. Problems in validation can be due to incompatibility of the CPX device and the validator. The comparison study of the four different systems showed that in the future standards for CPX testing should be defined.

[Comparison of four different methods for respiratory determination of the anaerobic threshold in normal people, and heart- and lung patients]. / Vergleich der vier verschiedenen Methoden zur respiratorischen Bestimmung der anaeroben Schwelle bei Normalpersonen, Herz- und Lungenkranken.

We analyzed 128 cardiopulmonary exercise tests (CPX), performed in normal subjects (n = 31), in patients with coronary artery disease (n = 41), with chronic heart failure before (n = 14) and after (n = 14) application of oral PDE-inhibitors and in patients with HIV-infection on a bicycle-ergometer in semi-supine position using a ramp-program (dependent on study-population with 15, 20 or 35 Watt/min increases) with respect to the ability to determine the respiratory anaerobic threshold non-invasively, using the main criteria described by Wasserman et al.: the V-slope-method according to Beaver, the increase of the ventilatory equivalent for O2 (VE/VO2), the increase of the end-tidal PO2 (PETO2) and the increase of the respiratory quotient (RQ) during exercise. In the different study-populations we calculated the detection rates of the AT for each criteria separately. The typical changes in the end-tidal PO2 (124/128 = 96.9%) and the V-slope-method (119/128 = 92.9%) were the most reliable parameters to detect the anaerobic threshold. The characteristic changes of the ventilatory equivalent for O2 (VE/VO2) and of the respiratory quotient (RQ) we found in 100/128 (= 78.1%) and in 107/128 (= 83.6%) of the tests respectively. 86/128 tests (67.2%) showed typical changes in all four mentioned criteria. In another 24/128 tests (19.8%) three of four criteria were fulfilled. Therefore, our investigations showed that in 110/128 cases (85.9%) the AT could be determined by typical changes by means of at least three of the four described parameters. In 15/128 (11.7%) tests only two of four criteria were fulfilled.(ABSTRACT TRUNCATED AT 250 WORDS)