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T Penzel

Publications and source records attributed to T Penzel.

At least 19 recordsLinked to original sources
PubMed2005

[Nocturnal long-term recording of breath sounds in patients with bronchial asthma -- a reasonable diagnostic option?].

Alterations in normal breath sounds are an important indication of pathophysiological processes in the bronchial system and the lung. In the presence of non-specific symptoms like dyspnea, wheezing or cough while sleeping it seems reasonable to make a nocturnal long-term recording of breath sounds. Thus specific auscultation phenomena can be recorded qualitative and particularly quantitative in the course. A mobile recording system provides a non-invasive monitoring at home which is independent of vigilance. Furthermore it can be used for follow-up examinations of medical interventions.

Asthma↗
PubMed2004

Influence of proportional assist ventilation on diaphragmatic activity in normal subjects.

In six awake healthy adults we studied the physiological effects of mechanical unloading of the respiratory muscles during increased ventilatory demand. We were interested in whether respiratory muscle activity is down regulated and if this is mainly a consequence of chemical factors, i.e. CO2-reduction, or non-chemical neuromuscular inhibition. With 33 mmHg inspiratory CO2 we induced modest hyperpnea of 24.4 +/- 3.9 L/min. Proportional assist ventilation (PAV) was applied with flow-related assist of 2.5 cm H2O/L/s and volume-related assist of 6 cm H2O/L. Respiratory muscle activity was measured by transdiaphragmatic pressure. Unloading caused a 57 percent reduction of the inspiratory transdiaphragmatic pressure-time product (p<0.05), while tidal volume, breathing frequency, and breathing pattern did not significantly change. These observations suggest that during increased ventilatory requirements, PAV results in down regulation of respiratory muscle activity and that this effect is mainly a consequence of neuromechanical inhibition.

Adult↗
PubMed2004

[Sleep disorders and sleep-related breathing disorders].

Normal sleep consists of 4-5 sleep cycles including light-, deep- and rapid eye-movement sleep. Restoration of physical and psychological function are the main effects of sleep. In most cases, disturbances of normal sleep become clinically evident as problems of initiating and maintaining sleep and/or as increased daytime sleepiness. Approximately 10% of adults suffer from pronounced insomnia, a similar percentage from markedly increased daytime sleepiness. Sleep disorders cause high socio-economic costs due to increased accident risk, cardiovascular sequelae and sick leave. Most of the 88 distinct diagnoses summarized in the international classification of sleep disorders can be differentiated and managed according to patients history. In patients with severe daytime sleepiness - sleep disordered breathing being the most frequent cause - the diagnostic evaluation and treatment in the sleep laboratory is required. Effective therapeutic strategies are available for many sleep disorders. According to the underlying disorder, treatment includes a variety of measures like life style changes, differentiated medical treatment and the use of nasally applied positive pressure in patients suffering from sleep disordered breathing.

Activities of Daily Living↗
PubMed2004

Interrater reliability between scorers from eight European sleep laboratories in subjects with different sleep disorders.

Interrater variability of sleep stage scorings is a well-known phenomenon. The SIESTA project offered the opportunity to analyse interrater reliability (IRR) between experienced scorers from eight European sleep laboratories within a large sample of patients with different (sleep) disorders: depression, general anxiety disorder with and without non-organic insomnia, Parkinson's disease, period limb movements in sleep and sleep apnoea. The results were based on 196 recordings from 98 patients (73 males: 52.3 +/- 12.1 years and 25 females: 49.5 +/- 11.9 years) for which two independent expert scorings from two different laboratories were available. Cohen's kappa was used to evaluate the IRR on the basis of epochs and intraclass correlation was used to analyse the agreement on quantitative sleep parameters. The overall level of agreement when five different stages were distinguished was kappa = 0.6816 (76.8%), which in terms of kappa reflects a 'substantial' agreement (Landis and Koch, 1977). For different groups of patients kappa values varied from 0.6138 (Parkinson's disease) to 0.8176 (generalized anxiety disorder). With regard to (sleep) stages, the IRR was highest for rapid eye movement (REM), followed by Wake, slow-wave sleep (SWS), non-rapid eye movement 2 (NREM2) and NREM1. The results of regression analysis showed that age and sex only had a statistically significant effect on kappa when the (sleep) stages are considered separately. For NREM2 and SWS a statistically significant decrease of IRR with age has been observed and the IRR for SWS was lower for males than for females. These variations of IRR most probably reflect changes of the sleep electroencephalography (EEG) with age and gender.

Female↗
PubMed2004

Sympathetic activity is reduced by nCPAP in hypertensive obstructive sleep apnoea patients.

There is increasing evidence that nasal continuous positive airway pressure (nCPAP) lowers blood pressure in obstructive sleep apnoea (OSA) patients, not only during sleep but also in the daytime. However, both the mechanisms of blood pressure reduction and the considerable differences in the magnitude of the effect in the studies presented to date are not fully understood. Therefore, the authors prospectively studied the effect of nCPAP on noradrenaline plasma levels (NApl), blood pressure and heart rate (HR) in 10 normotensive and eight hypertensive OSA patients before and after 41.6 +/- 16.9 days of nCPAP therapy. Polysomnography and invasive blood pressure were continuously monitored over 24 h in the supine position before and with nCPAP. NApl were analysed every 15 min. In hypertensives, nCPAP reduced NApl by 36 +/- 25%, lowered mean arterial blood pressure substantially (night-time: -8.89 +/- 14.09 mmHg; daytime: -7.94 +/- 10.47 mmHg) and decreased HR by 6.6 +/- 5.4 beats x min(-1), whereas in normotensives there were only minor changes. The decrease in heart rate was associated with a decrease in mean arterial blood pressure and noradrenaline plasma levels, suggesting a causal effect of nasal continuous positive airway pressure therapy. This nasal continuous positive airway pressure effect occurs mainly in hypertensive obstructive sleep apnoea patients, whereas the effect is small in normotensives. This may explain, at least in part, some of the discrepant results in previous treatment studies.

Adult↗
PubMed2004

Automatic CPAP titration with different self-setting devices in patients with obstructive sleep apnoea.

Autotitrating continuous positive airway pressure (CPAP) devices automatically adjust the pressure according to upper airway obstructions. The aim of this study was to compare the treatment effects of different automatic CPAP devices (AutoSet, Horizon and Virtuoso) with conventional CPAP in patients with obstructive sleep apnoea independently of financial manufacturer support. Twelve male patients with obstructive sleep apnoea were submitted to a crossover study protocol with overnight polysomnography for 6 consecutive nights. After diagnostic polysomnography, the CPAP pressure was manually titrated. Over the next 4 nights, the patients were treated with any one of the three automatic CPAP devices or fixed CPAP in random order. The apnoea/hypopnoea index on the diagnostic night was 67.3+/-21.7 events h(-1), and was significantly reduced to 0.7+/-1.2, 3.0+/-2.9, 2.3+/-2.5 and 12.0+/-13.6 events x h(-1) with the fixed CPAP, AutoSet, Horizon and Virtuoso devices respectively. An apnoea/ hypopnoea index of <5 events h(-1), an indicator of optimal treatment, was achieved in all patients with fixed CPAP and in 10 patients using the Autoset and Horizon devices, but in only six of the 12 using the Virtuoso. The mean pressure was significantly lower with the AutoSet and Virtuoso devices, but not with the Horizon as compared to fixed CPAP. The maximum pressure was significantly higher with the Horizon. It is concluded that automatic continuous positive airway pressure devices produce a significant reduction in apnoea/hypopnoea index; however, there is considerable difference in the efficacy of the various devices.

Adult↗
PubMed2003

[Why is obstructive sleep apnea (OSA) a cardiovascular risk factor?].

Patients with obstructive sleep apnea (OSA) frequently suffer from cardiovascular diseases. Mechanisms like intrathoracic pressure variations, changes in blood gases (hypoxia), arousals and neurohumeral adaptation mechanisms, combined with breathing disorders are causing these cardiovascular sequelae. In particular repetitive hypoxemia and activation of the sympathetic nervous system have to be considered as stressors for the cardiovascular system. Special clinical findings should take OSA into consideration as a differential diagnosis. A systematic anamnesis with questions to daytime conditions (hypersomnia, decrease of performance), snoring and apneas while sleeping is easy to ascertain, and will lead to the correct diagnosis in more than 90% of cases. The extent and need for therapy should be assessed by three criteria: 1) daytime symptoms, 2) the extent of breathing disorder and 3) cardiovascular comorbidity.

Arousal↗
PubMed2003

[Acoustic follow-up of nocturnal bronchial obstruction therapy].

Long acting beta 2-agonists belong to the basic therapy of COPD. Especially patients with nocturnal respiratory problems may benefit from this therapy. Long term recording of lung sounds is a new method for quantitative measurements of bronchial obstructions. In combination with polysomnography an evaluation of cardiorespiratory parameters and sleep structure is possible. A total of 10 patients (8 male and 2 female) with moderate COPD (FEV1 58 +/- 11 %) and signs of bronchial obstruction were investigated. The combination of acoustic long term recording and polysomnography was done for 2 or 3 nights without and under therapy (long acting beta 2-agonist, 50 microg Salmeterol). In all patients we could find nocturnal bronchial obstruction events. Nocturnal wheezing time was reduced during therapy to 33 +/- 17 % (1. therapy night, n. s.) compared to 49 +/- 30 % without therapy (control night) and to 17 +/- 17 % (2. therapy night, n = 6, p < 0.05) vs. 51 +/- 30 % (control night, n = 6). Sleep efficiency and REM sleep increased (n. s.) under therapy, deep sleep stages NREM III/IV were nearly the same. Acoustic long term monitoring confirms the reduction of nocturnal bronchial obstructions under therapy with beta 2-agonists. A better sleep quality may be expected from the improvement of the respiratory situation during sleep.

Adrenergic beta-Agonists↗
PubMed2003

[Effect of subcutaneous fatty tissue on normal respiratory sounds].

Auscultation is an important, non-invasive and simple measure in the diagnosis of lung diseases that can detect sometimes pathological processes prior to radiography. Attempts have already been made to automatically detect characteristic pathological sounds, but a knowledge of potential influencing factors is a must for correct interpretation. In this study we have investigated the effect of the subcutaneous fat layer on normal lung sounds. This is of importance to determine corrective factors for the automatic detection of bronchial breathing in pneumonia. The lung sounds of 125 healthy people (55f, 70m) were digitally recorded at four different positions of the thorax (3. ICR paravertebral, 7. ICR medioscapular, all left and right). Evaluation was done separately for gender. The subcutaneous fat layer was measured with a Holtain Skinfold Caliper at the identical four recording positions. For a quantitative evaluation of the sounds we calculated the relative power of frequency bands 330-600 Hz and 60-330 Hz and their ratio. The relation between these parameters and the subcutaneous fat layer was analyzed with the Pearson correlation. The results of this study show that the influence of subcutaneous fat layer is negligible and can be ignored in the automatic detection of lung sounds.

Adipose Tissue↗
PubMed2002

Systematic comparison of different algorithms for apnoea detection based on electrocardiogram recordings.

Sleep apnoea is a common disorder that is usually diagnosed through expensive studies conducted in sleep laboratories. Sleep apnoea is accompanied by a characteristic cyclic variation in heart rate or other changes in the waveform of the electrocardiogram (ECG). If sleep apnoea could be diagnosed using only the ECG, it could be possible to diagnose sleep apnoea automatically and inexpensively from ECG recordings acquired in the patient's home. This study had two parts. The first was to assess the ability of an overnight ECG recording to distinguish between patients with and without apnoea. The second was to assess whether the ECG could detect apnoea during each minute of the recording. An expert, who used additional physiological signals, assessed each of the recordings for apnoea. Research groups were invited to access data via the world-wide web and submit algorithm results to an international challenge linked to a conference. A training set of 35 recordings was made available for algorithm development, and results from a test set of 35 different recordings were made available for independent scoring. Thirteen algorithms were compared. The best algorithms made use of frequency-domain features to estimate changes in heart rate and the effect of respiration on the ECG waveform. Four of these algorithms achieved perfect scores of 100% in the first part of the study, and two achieved an accuracy of over 90% in the second part of the study.

Algorithms↗
PubMed2002

A new design of a polysomnography-based multi-center treatment study for the restless legs syndrome.

Periodic limb movements (PLM) cause sleep disorders and daytime symptoms and are frequently associated with restless legs syndrome (RLS). Treatment of RLS with increased PLM during sleep (PLMS) has been evaluated in studies limited in size, methodology and study length. This long-term, placebo-controlled, multi-center, study with polysomnography (PSG) recordings has been designed in order to assess efficacy and safety parameters of pergolide treatment in RLS. This novel approach for a study was created to assure consistently high quality of sleep recording and analysis. Using defined criteria, 21 sleep centers were approved for the study after a pilot phase. Seventeen centers with 16 different PSG systems randomized 100 patients. Digital sleep recordings from 4 visits (baseline, 6 weeks, 6 months, 1 year) were submitted to one central evaluation center following previously defined standardized operating procedures. Visual scoring of all recordings was performed by one independent scorer. Reliability of scoring was evaluated for 20 randomly selected baseline recordings. The mean epoch by epoch agreement for sleep stages was 88% (range 81-96%), mean arousal re-scoring differed by 0.5 (range: -16 to 20), and mean PLM index re-scoring differed by 0.1 (range: -1.5 to 2.1). Using one scorer with a demonstrated high reliability in PSG scoring for all sleep recordings was very effective in terms of study cost, study duration, and data quality.

Dopamine Agonists↗
PubMed2002

[Acoustic analysis of nocturnal bronchial obstruction].

Patients with obstructive pulmonary disease also have respiratory problems in sleep. The continuous acoustic lung sound detection together with a cardiorespiratory polysomnography allows a synchronous registration of bronchial obstruction as well as vigilance and respiratory parameters in sleep.A total of 20 patients (9 male and 11 female) with known obstructive airway disease and evident diurnal bronchial obstruction were investigated. We did a monitoring in all patients with a nocturnal continuous acoustic lung sound detection together with a cardiorespiratory polysomnography. The mean age was 55 +/- 12 years (range 23 to 74). In all patients acoustic nocturnal bronchial obstructions could be registered. The wheezing-time (time portion of wheezing while sleeping) was 32.1 +/- 27.4 % (mean +/- SD). We could not proof reliable a rhythm of bronchial obstructions. Only 3 patients had increased bronchial obstructions between 3 and 5 AM. The sleep structure was disturbed in 16 of 20 patients with reduced deep sleep, REM sleep and prolonged sleep latency. Knowing about nocturnal bronchial obstructions helps to adapt the antiobstructive therapy. One can expect that an improvement of the respiratory situation also improves sleep quality.

Adult↗
PubMed2002

The SleepStrip: an apnoea screener for the early detection of sleep apnoea syndrome.

Sleep apnoea svndrome (SAS) is a largely undiagnosed and prevalent disorder. It is associated with cardiovascular morbidity as well as excessive daytime sleepiness and poor quality of life. In the present study the SleepStrip, a novel screening device is introduced, which is low cost and easy to use and is aimed for widespread use. The results of three independent validation studies, which compared the SleepStrip score (Sscore) against "gold standard" polysomnographically-determined apnoea/ hypopnoea index (AHI), are reported both separately and combined. Four hundred and two patients suspected of SAS underwent full polysomnography recordings concomitantly with the use of the SleepStrip. For all samples combined, the correlation between AHI and Sscore was r=0.73, sensitivity and specificity values ranged from 80-86% and 57-86% respectively, and the area under the curve derived from receiver-operating characteristic curves ranged from 0.81-0.92 at varying AHI thresholds. Though not intended as a substitute for polysomnography, the SleepStrip may provide initial screening information, which may be useful in both clinical and experimental settings.

Adolescent↗
PubMed2002

Peripheral arterial tonometry for the diagnosis of obstructive sleep apnea.

Sleep related breathing disorders have been recognized as a risk factor for cardiovascular disorders. Peripheral arterial tonometry (PAT) allows to monitor vasoconstriction on the finger continuously and non-invasively. We investigated whether the rapid changes of autonomous function can be assessed by PAT. In 21 patients with obstructive sleep apnea and arterial hypertension we recorded PAT in parallel to cardiorespiratory polysomnography and invasive arterial blood pressure. The correlation between periodic PAT attenuations and the total number of apneas (r = 0.656, p < 0.01) and the total number of cortical arousal (r = 0.583, p < 0.01) were significant. The PAT signal cannot substitute blood pressure but allows a good recognition of apneas and subcortical arousal and gives additional information on changes of sympathetic and parasympathetic tone during sleep.

Adult↗