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Biomedical subjects

T Penzel

Publications and source records attributed to T Penzel.

At least 73 records · Page 4Linked to original sources
PubMed1993

[Validation study of the 10-channel Sidas 2010 registration unit for diagnosis of sleep-related respiratory disorders].

UNLABELLED: We developed in cooperation with F. D. Stott, Oxford, the Mobile 10-Channel Unit SIDAS 10, a recording instrument for diagnosing sleep-related breathing disorders, to cope with the large number of patients requiring to be diagnosed. Studies that have already been published prove the clinical worth of this instrument that has been conceived as a mobile unit for the diagnosis of sleep-related breathing disorders outside a conventional sleep laboratory. To test the validity of this unit the present study was designed as a comparative study of conventional polygraphs versus SIDAS recordings. METHOD: 20 unselected patients (18 men, 2 women), average age 54.8 (34-65) years, body mass index (BMI) 29.8 (20.2-46.2) kg/m2, were examined parallel for one night in the sleep laboratory. We compared the breathing a) recorded with nasal airflow, oesophageal pressure, oxygen saturation and b) with induction plethysmography, ITP (a non-invasive recording of intrathoracic pressure variations), nasal airflow and pulse oxymetry via SIDAS 2010. The writeouts were evaluated visually according to internationally valid criteria. RESULTS: We found 10 patients with an apnoea index (AI) > 10/h (mean AI 53.2), 4 patients with AI between 5 and 10/h (mean AI 6.4) and 6 patients with an AI < 5/h (mean AI 3.4). 5835 apnoeas and hypopnoeas were evaluated. The statistical analyses yielded the following results: equal classification of central apnoeas in 87%, of obstructive apnoeas in 90% and of mixed apnoeas in 92% of the cases; on the whole, 10% more hypopnoeas were classified in the SIDAS recordings.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

[Sleep analysis computer in diagnosis of sleep-related respiratory disorders].

Sleep related breathing disorders influence the structure of sleep by considerably modifying the ratios of the individual sleep stages. The sleep analyses carried out by polysomnography in the diagnosis of sleep related breathing disorders have so far been evaluated manually according to the criteria of Rechtschaffen and Kales, since automatic systems do not permit standardised evaluation as yet. Automatic sleep analyses via SAC, however, has been developed further in recent years and has widened its scope and efficiency. It is now possible to perform a comprehensive sleep analysis via SAC by means of modified criteria after Rechtschaffen and Kales. The SAC determines individual curves in the EEG and EOG and includes in addition to the EEG parameters an automatic apnoea detection as well as detailed breathing and oxygen saturation analyses. The Sleep Analysis Computer (SAC) records 15 parameters (2 EEG, 2 EOG, 2 EMG, ECG, NAF, thoracic and abdominal breathing curves, oxygen saturation, body posture, optionally blood pressure = RR, CPAP etc.). This means that all the parameters required for diagnosing sleep related breathing disorders as well as their differential diagnosis can be determined. Within the framework of a blood pressure study, 16 patients (average 45.5 SD 4.6 years) were subjected to SAC measurement in addition to conventional PSG. The computer recordings were evaluated according to apnoea index, the form of the apnoea and the oxygen saturation desaturations. The evaluation yielded the following pattern: 4 patients with AI < 10, 8 patients with AI between 10 and 20, 4 patients with AI > 20. Obstructive apnoeas were seen in 6 patients, mixed apnoeas in 8 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Cerebral Cortex↗
PubMed1993

[Effect of obstructive sleep apnea on preload of the right heart].

Obstructive sleep apnea (OSA) is characterized by a total inspiratory occlusion of the extrathoracic airways with persisting respiratory effort. During obstructive breathing efforts the intrathoracic pressure (ITP) falls below-20 Torr. This should augment venous return by depleting the blood from the extrathoracic veins into the thoracic veins, thus pre- and afterload of the right heart rises. Until now preload of the right heart during OSA was not measured. This study shows the filling pressures (tmPRA) of the right heart during OSA. In five patients the in- and expiratory right atrial pressure and the intrathoracic pressure were measured, beat by beat, during the non REM hour in which the most apnea episodes occurred. The tmPRA values were calculated as follows: tmPRA = PRA-ITP. The rising tmPRA with falling ITP shows that the venous return, during apnea episodes, rises mostly unhampered. Only in one patient did a cut-off of the increasing tmPRA occur. This patient showed a flow limitation of venous return. Two more patients developed different trends. One part of the measurements led to a linear increase of tmPRA, the other part shows a plateau up from a certain ITP. In two patients tmPRA increases linearly, in the extreme, with decreasing ITP. This indicates no flow limitation of venous return. The results of this investigation suggest that the protective mechanism of the limitation of venous return, occurring under artificial conditions, does not regularly appear in patients with OSA. This leads to repetitive volume overloads of the right heart.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

[Long-term registration of arterial blood pressure in sleep with noninvasive methods].

Sleep related breathing disorders and essential hypertension are highly interrelated. Many different studies proved a casual relationship between the two disorders (1,2). In a clinical sleep laboratory diagnostics of hypertension has to be non-invasive. There are two completely different methodologies to record blood pressure noninvasively. Continuous methods using fingerphotoplethysmography can record apnea related cyclical variations of blood pressure beat to beat. Unfortunately the absolute value of the pressure readings is sensitive to the position of the finger sensor. Noncontinuous methods using arm cuff inflation preserve appropriate blood pressure values but these are only spot measures during the night. To make use of these it is necessary to record other sleep and respiration related signals in parallel. Both methods were applied in our sleep laboratory and results are presented.

Blood Pressure↗
PubMed1993

[Measuring circadian core temperature periodicity without masking in obstructive sleep apnea].

Although close interactions between sleep respectively sleep disturbances and the circadian system are known, chronobiological aspects have not been taken into account sufficiently in investigation and therapy of obstructive sleep apnea (OSA). We carried out a 24-hours lasting constant routine. Considering the circadian course of core temperature, patients with OSA show an impairment of the circadian system, which improves after three nights with nCPAP-treatment.

Adult↗
PubMed1992

Ambulatory diagnosis of sleep-related breathing disorders.

Ambulatory diagnosis of sleep-related breathing disorders (SRBD) is necessary due to their high prevalence and to the limited capacities of sleep centers. Categories of SRBD which must be diagnosed and differentiated are defined. Indications for ambulatory diagnosis are given. A selection of systems on the market in Europe are given and described in terms of their parameters. The correct system for diagnosis in a specific patient must be selected according to the specific question. The issue of ambulatory diagnosis of SRBD has gained importance in Germany because beginning in spring 1992 physicians will be reimbursed if they continuously record respiratory signals, heart rate, oxygen saturation and movement in their patients and if they qualify by attending a one-week training course.

Airway Obstruction↗
PubMed1992

[Analysis of long-term blood pressure measurements during sleep].

Fifty patients with sleep-related breathing disorders and arterial hypertension underwent diagnostic polysomnography for two nights; EEG, EOG, EMG, and respiratory signals were recorded in parallel with invasive blood pressure. Computerized evaluation was performed to calculate systolic and diastolic blood pressure values, as well as heart rate beat-to-beat. All signals were stored once per second for further evaluation. These time series were analyzed in respect of underlying periodicities by means of spectral analysis. It was possible to distinguish four different groups of patients according to the compressed spectral arrays. Pronounced peaks of different extents were found that reflected both periodicities of respiration (3-5 s) and periodicities of sleep apnea (30-60 s). A comparison of spectral analysis of blood pressure and heart rate showed that systolic blood pressure is suited best to recognize periodicities related to respiration and apneas.

Adult↗
PubMed1992

Continuous non-invasive blood pressure monitoring in patients with sleep disorders.

Sleep related breathing disorders are of high prevalence and are often associated with essential hypertension. It is therefore necessary to study blood pressure continuously in all patients with sleep related breathing disorders and arterial hypertension as well as in all patients with essential hypertension and suspected sleep apnoea. To investigate the usefulness of a non-invasive continuous volume-clamp method during sleep we used this technique in parallel with 130 sleep recordings and performed a validation study of the Finapres instrument on a subgroup where continuous invasive blood pressure recordings were available. Absolute pressure values of Finapres are valid when the position and the movement of the sensor were carefully observed and only appropriate segments of the recordings were taken for further evaluation. The high beat to beat resolution of the systolic and diastolic pressure is the main advantage of this non-invasive technique because it reflects rapid blood pressure variations as they occur in sleep related breathing disorders. This could be investigated only invasively until now.

Blood Pressure Determination↗
PubMed1991

Blood pressure and sleep apnea: results of long-term nasal continuous positive airway pressure therapy.

Arterial blood pressure patterns in 12 men with sleep apnea and arterial hypertension were studied at baseline and after 6 months' therapy with nasal continuous positive airway pressure (nCPAP). Preexisting antihypertensive medication was discontinued 1 week before baseline measurements. Weight did not change during the study period; body mass index was 29.3 (range, 25.4-38.5) vs. 29.3 (25.0-38.5). During therapy the apnea index decreased from 58 (range 30-73) to 2 (range 0-7) apneic episodes per hour (p less than 0.01). Intra-arterial systolic (BP sys.) and diastolic (BP dias.) blood pressure and heart rate decreased during therapy (p less than 0.001). Mean values +/- 95% confidence intervals were as follows: BP sys., 147.1 (+/- 1.6) mm Hg vs. 126.4 (+/- 1.5) mm Hg; BP dias., 81.6 (+/- 0.8) mm Hg vs. 69.4 (+/- 0.6) mm Hg; heart rate, 68.8 (+/- 0.7) beats/min vs. 65.4 (+/- 0.7) beats/min. Furthermore, the variability of these parameters decreased during therapy: variability BP sys., 53.8 (+/- 1.1) mm Hg vs. 25.6 (+/- 1.1) mm Hg; variability BP dias., 35.6 (+/- 0.7) mm Hg vs. 17.9 (+/- 0.7) mm Hg; variability of heart rate, 28.1 (+/- 0.7) beats/min vs. 14.9 (+/- 0.7) beats/min (p less than 0.001). During treatment we found that blood pressure scores already dropped during the awake phase, with a further decrease during non-REM and REM sleep (p less than 0.001). Our results, which demonstrate the reversibility of high blood pressure upon treatment of sleep apnea, indicate that sleep apnea can be an etiological factor in hypertension. Sleep apnea should therefore be considered in the differential diagnosis of arterial hypertension.

Adult↗
PubMed1991

[Computer analysis of disturbed respiration in patients with sleep apnea].

In patients with sleep related breathing disorders parallel evaluation of respiration, blood gases and the EEG are indispensible. Computerized methods can provide a detailed analysis of the interrelation of these parameters to enlighten the disturbed central regulation of respiration in these patients. These methods also can help to achieve a better differential diagnosis in routine clinical work. A new method is presented here which evaluates the signals of nasal airflow, thoracic and abdominal movements together with oxygen saturation and heart rate in parallel. The new method is validated using a detailed visual analysis. Results prove the usefulness of the new method. To apply the method the relationship between length of apnea and oxygen desaturation is evaluated for different sleep stages separately.

Blood Gas Analysis↗
PubMed1991

[Assessment of the MESAM and Biox 3700 early warning methods for the diagnosis of sleep-related respiratory disorders in young men].

We can use pulse oximetry as a method for diagnosis of the sleep apnoea syndrome, as well as L-EKG, MESAM II and the actigraph. In this study MESAM II and pulse oximetry were combined for finding out discrete sleep-related breathing disorders. The results were compared with polysomnography. 5 (15.1%) of 32 patients had an index of apnoea (AI) greater than 10, whereas 4 (12.1%) patients showed an AI greater than 5. All of the patients with positive signs in MESAM II/pulse oximetry had an AI greater than 5 in polysomnography, whereas non of the patients with negative signs in MESAM II/pulse oximetry had an AI greater than 5 in polysomnography.

Adult↗
PubMed1991

[SIDAS 2010: mobile 10-channel unit for the diagnosis of sleep-related respiratory disorders].

At the moment diagnosis of sleep related breathing disorders (SRBD) is carried out in specialised clinical centres with well-equipped sleep laboratories. Since there are only few of these in Germany, medical care in this field is not sufficient at all even if applied only to high-risk patients. To cope with the large number of patients with severe SRBD we developed a mobile 10-channel unit (SIDAS 2010) designed for diagnosing SRBD even outside the conventional sleep laboratories. In this study we investigated 108 patients who after using the 4-channel recorder presented signs and symptoms suggesting SRBD. After evaluating the tracings in 53 patients a distinct obstructive sleep apnoea (OSA) (AI 10) could be diagnosed; in 55 patients the signs remained indistinguishable. In 2 recordings with SIDAS in 74 patients, a distinct OSA was diagnosed, 34 patients had an AI less than 10; these patients underwent renewed polysomnographic recordings with EEG in addition. The polysomnographic recordings revealed 5 patients with an AI between 5 and 10.3 with primary and secondary alveolar obstructive hypoventilation due to excessive snoring. The comparison of SIDAS recordings with recordings made by polysomnography proved SIDAS to be valuable in respect of diagnosing type of SRBD (obstructive/central) and amount of respiratory events (apneas/hypopnoeas). In this study only 13 patients with SRBD (14.9%) need further diagnostic procedures. We conclude that with SIDAS most of the SRBD can be diagnosed sufficiently even outside conventional sleep laboratories.

Adult↗
PubMed1990

MESAM: a heart rate and snoring recorder for detection of obstructive sleep apnea.

The high prevalence of sleep-related breathing disorders demands the development of ambulatory recording devices that can handle data with a high degree of selectivity and are easy to use and to interpret. A digital device based on the recording of heart rate and breathing sounds was developed. Patients with sleep-related breathing disorders can be preselected before they undergo sleep laboratory investigations. Treatment control can be achieved ambulatory, having an initial recording.

Ambulatory Care↗
PubMed1989

Effects of cilazapril on hypertension, sleep, and apnea.

Epidemiologic studies revealed that up to 10 percent of middle-aged men show more than 10 cessations of breathing of more than 10 seconds' duration. In these patients, increased morbidity and mortality rates have been proved. More than 50 percent of apnea patients exhibit arterial hypertension, and up to 50 percent of hypertensive patients experience sleep apnea. Patients with sleep apnea and essential hypertension need special attention paid to their antihypertensive therapy because the following side effects of drugs have to be avoided: increases of cardiac insufficiency, hyperviscosity of the blood, intensification of the hypersomnia by central sedation, intensification of a pre-existing tendency towards arrhythmias, and deprivation of deep and rapid eye movement sleep. In this study, the effects of angiotensin-converting enzyme inhibitors in patients with sleep apnea and hypertension are examined. An interim evaluation of six patients (aged 50 to 57) yielded the following results: Average Broca index, 124; average blood pressure before therapy, 159/102 mm Hg; average blood pressure after therapy, 132/78; a decrease of the apnea and hypopnea index from x = 31 (range, 12 to 77) to x = 20 (range, two to 54). Therapy did not influence sleep structure: before therapy, an average of 19 percent of sleep episodes were of the rapid eye movement type (range, 11 to 32 percent); after therapy, 23 percent were of this type on average (range, 21 to 25 percent). A final evaluation will be carried out after the second study phase for 12 patients who have been treated in a double-blind scheme with metropolol versus cilazapril.

Adult↗
PubMed1989

[Snoring and sleep apnea syndrome].

Sleep apnea and obstructive snoring are sleep related breathing disorders (SRBD). Nevertheless, there is only a quantitative difference between snoring and the obstructive form of sleep apnea. Snoring occurs in at least 20% of the population; 50% of the 50 year old male snore. Although in most of the cases only harmless snoring is concerned. It becomes serious if it leads as the independent SRBD "obstructive snoring" to a continuous oxygen desaturation and a sleep disturbance or, if in cases of sleep apnea a postapnoic snoring is concerned. The snoring pattern "loud and irregular" is always a sign for a serious SRBD. Still, no exact statement can be given concerning the frequency of obstructive snoring. However, the prevalence of sleep apnea in men of the mean age group has been determined to 10%. By the so-called sleep apnea syndrome are summarized clinical pictures with symptoms and findings caused by sleep apnea, respectively with those which can be reduced by sufficiently early introduced therapy. Most frequent symptoms and findings are: hypertension, loud and irregular snoring, daytime sleepiness and nocturnal cardiac arrhythmias. Especially hypersomnia has always to be taken seriously. In relation with other symptoms and findings associated with apnea it is always an indication for the examination for sleep apnea and obstructive snoring.

Brain↗