Portable recording to assess the severity of obstructive sleep apnea: a European perspective.
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Equipment Design↗
Biomedical subjects
T Penzel
Publications and source records attributed to T Penzel.
Blood pressure analysis.
Arterial blood pressure is influenced by sleep-related breathing disorders. As cardiovascular consequences can be diagnosed by an accurate recording and analysis of blood pressure, new recording methodologies and an approach to analysis are presented here. Invasive continuous blood pressure recording is the common reference for all methodologies. As blood pressure varies rapidly in parallel with sleep-related breathing disorders it is indispensible to record blood pressure continuously. To introduce non-invasive methodology the Finapres system was used during sleep studies; a validation study showed severe limitations. This study was followed by the validation of an improved system called Portapres, which is portable, has two finger cuffs and a hydrostatic height compensation. Analysis of continuous blood pressure in patients with sleep apnoea is carried out to detect mechanisms which influence the cardiovascular risk. Spectrum analysis of systolic blood pressure showed two different major oscillations present in patients with obstructive sleep apnoea. One oscillation (<0.06 Hz) occurs in parallel with each apnoeic episode and the other oscillation (0.2-0.4 Hz) occurs in parallel with the obstructive efforts during each apnoea and in parallel with respiration during periods of snoring. These two oscillations were so specific that the use of non-invasive continuous blood pressure recording allowed an estimation of the extent of underlying breathing disorders, and assessment of cardiovascular risk in a patient with obstructive apnoea in terms of hypertension and on the basis of ambulatory monitoring.
Journal Article↗
Arterial hypertension and sleep apnoea: effect of the angiotensin-converting enzyme (ACE) inhibitor cilazapril on continuously measured blood pressure during sleep and wakefulness.
Male patients with arterial hypertension and obstructive sleep-related breathing disorders (mean age 50 y, Body Mass Index (BMI) 32.4 kg m-2, Respiratory Disturbance Index (RDI) 47.2 and systolic/diastolic blood pressure (SBD/DBD) 162/103 mmHg) were examined before and after 8 days of treatment with the long-acting angiotensin-converting-enzyme (ACE) inhibitor cilazapril 2.5 mg vs. placebo in a double-blind design with parallel groups. Cardiorespiratory polysomnography was carried out at night; during daytime wakefulness patients submitted to examinations of physical and mental exertion. Cilazapril reduced the mean pressure during the entire examination period (day and night) by 9.55 (SD +/- 7.13) mmHg, compared to 4.57 (SD +/- 7.20) mmHg for placebo (P < 0.006), independently from systematic changes of heart rate (x = -3.3 and -3.5 bpm, respectively). During REM sleep, mean arterial pressure was significantly reduced by 8.63 (SD +/- 10.1) mmHg, compared to a reduction on placebo of 3.17 (SD 9.6) mmHg (P = 0.023). Under psychometric strain, the mean arterial pressure was reduced by 15.31 (SD +/- 8.7) mmHg with cilazapril; under placebo medication by 6.19 (SD +/- 7.3) mmHg (P < 0.0001). Heart rate was not significantly changed.
Journal Article↗
Multi-centre comparison of five eye movement detection algorithms.
Although various investigators have suggested algorithms for the automatic detection of eye movements during sleep, objective comparisons of the proposed methods have previously been difficult due to different recording arrangements of different investigators. In this study the results of five eye movement detection algorithms applied to the same data were compared to visually scored data. The percentages of true and false detections are given for various threshold levels in rapid and slow eye movement detections. The methods gave best results when they were used with the same electrode montage they were designed for but the performance decreased when other montages were used. Subtracting the cross-talk of EEG delta activity improved the correctness of eye movement detections.
Journal Article↗
Interactive computer program for the analysis of cardiovascular polysomnographic recordings.
A computer program for the analysis of blood pressure, heart rate, oxygen saturation and some other polysomnographic signals is presented. The program analyzes the signals, digitized by using a 100 Hz sampling frequency, in one second resolution. The analysis and calibration periods can be entered to the program by pointing at the appropriate positions of the displayed signal with a mouse. As analysis results the program can produce statistical tables or graphical representations of the measured variables as a function of time. The program can be used in routine polysomnographic cardiovascular analysis and due to its flexibility also in experimental studies.
Blood Pressure↗
[Detecting blood pressure variation using spectral analysis in obstructive sleep apnea syndrome with and without nCPAP therapy].
The variation of blood pressure was investigated by power spectrum analysis in 12 patients with severe sleep apnea with and without nCPAP-therapy. In the baseline findings systolic and diastolic variation consisted of mainly two types of pressure oscillations: Swings of slow frequency (0-0.06 Hz) in tight association with the periodicity of breathing disorder and arousal and extensive respiratory pressure waves (0.2-0.5 Hz) due to the increased intrathoracic pressure changes during breathing efforts with partial or complete obstruction of the upper airway. In general systolic was higher than diastolic variation and the contribution of slow pressure oscillations was considerably bigger than that of respiratory waves. Sufficient nCPAP-therapy resulted in a decrease of the mean pressure and in a clear reduction of systolic and diastolic variation in which both types of pressure waves were diminished in a similar manner. At last there was a higher proportion of pressure waves in the frequency range of the Mayer-waves (0.06-0.2 Hz) with nCPAP-therapy.
Adult↗
[Machine-assisted detection of individually effective minimal CPAP pressure using the Vitalog HMS 5000 monitor].
UNLABELLED: Continuous positive airway pressure ventilation (CPAP) has been proven to be highly effective in the elimination of sleep-related breathing disorders (SRBD) in the last couple of years. The titration of the effective airway pressure should be carried out under continuous polysomnographic supervision in the sleep laboratory. The CPAP ventilation may result in potential hazards through the positive airway pressure and each patient needs an individually adjusted pressure for therapy. In a prospective study we investigated under polysomnographic supervision the effectivity and the hazards of a machine-controlled CPAP calibration in 22 male patients (pts) (age: 53.6 +/- 8.9 years, BMI: 29.9 +/- 5.0 kg/m2) with obstructive SRBD (RDI: 50.6 +/- 1/h). Automatic CPAP-calibrations were carried out using the Vitalog HMS-5000 monitor and the Respironics BiPAP-STD ventilator. An algorithm determined the cyclical changes of the airway pressure. The following night we controlled the assessed pressure through manual adjustment during conventional polysomnography. RESULTS: The CPAP-levels assessed through the automatic calibrations (8.36 +/- 2.36 cmH2O) showed in 19 pts a good agreement with the CPAP-levels of the control nights (8.15 +/- 2.36 cmH2O), the difference was statistically nonsignificant (p < 0.5). The CPAP-levels of the automatic titrations and the control nights agreed exactly in 12 pts (63%). 3 pts of the 22 failed the automatic CPAP-titration process because of functional or psychical reasons. 14 pts (64% of 22 pts) showed a good functional tolerance to the cyclical changes of the airway pressure. 3 pts were unable to fall asleep under the increasing airway pressure, but after falling asleep at a constant pressure of 2 or 4 cmH2O they could tolerate the automatic pressure titration. A reset of the actual pressure to the baseline was necessary in 13 pts to enable them falling asleep, in 2 pts because of increase of the airway pressure due to movement artifacts, in 2 pts because of central apneas and in one patient because of ventricular extrasystoles. 35 increases of the baseline level (48% of altogether 73 increases) occurred due to clinically irrelevant desaturations. We found a direct hazardous effect of the machine-controlled CPAP-titration (central apneas, secondary alveolar hypoventilation, ventricular extrasystole) in 7 pts with chronic obstructive pulmonary disease and/or cardiovascular disorder. CONCLUSION: The machine-controlled CPAP-titration should be carried out only in a selected group of patients. Nevertheless, despite of the good agreement of the assessed pressure levels with the polysomnographic controls, this method seems to be not suitable for the clinical routine because of its potential hazards and contraindications in high risk patients.
Adult↗
[Status of cardiorespiratory polysomnographic diagnosis in the sleep laboratory].
The different types of sleep related breathing and cardiovascular disorders are well known and defined nowadays. Thereby it is possible to present a configuration by which a cardiorespiratory sleep laboratory is enabled to perform a complete differential diagnosis. This configuration consists of the function sleep with EEG, EOG and EMG, the function respiration with respiratory effort, respiratory flow and oxygen saturation, and the cardiovascular function with ECG and blood pressure if indicated. Continuous monitoring by videocamera and a patient call system with a technician present during the entire recording time must be assured. Recording and evaluation of all signals can be done with chart polygraphs or with computer systems if they provide a high-resolution graphic monitor. Automatic sleep analysis systems support evaluation of polysomnograms. But automatic analysis of sleep stages as well as automatic analysis of respiratory disorders needs visual counterchecking before results can be accepted. On the basis of today's knowledge recommendation for the setting of a sleep laboratory were set and new sleep labs are controlled on a voluntary basis by a commission of the German society for sleep research and sleep medicine. This first step of quality control is introduced to establish a procedure to keep quality of diagnosis and treatment on a high level in this medical specialty.
Hemodynamics↗
Twenty-four-hour blood pressure control: effect of cilazapril on continuous arterial blood pressure during sleep, and physical and mental load in patients with arterial hypertension and sleep apnea.
To assess the effectiveness of cilazapril in regulating blood pressure (BP) in patients with sleep-related breathing disorders, 23 male patients (mean age, 50 years; mean body mass index, 32.7 kg/m2) with a mean apnea/hypopnea index of 49.7 and arterial hypertension (163/104 mm Hg) participated in a placebo-controlled, randomized, double-blind study. They received either cilazapril, 2.5 mg/day (n = 12) or placebo (n = 11). The effects of treatment were studied under different conditions of sleep and physical and mental load before and after 8 days of treatment. Measurements by night included cardiorespiratory polysomnography, inductive plethysmography, pulse oximetry and nasal air flow, electroencephalography, (EEG), electrooculography and electromyography, (ECG), and blood pressure (BP). Measurements by day (ECG, heart rate, and BP) were performed at rest and under physical and mental load. Systolic, diastolic, and mean BP (5 min at night; 1 s during the day), heart rate, apnea and hypopnea index, EEG data, and test reaction times were compared in both groups. The systolic and diastolic BP of patients receiving cilazapril was lower compared to baseline for all physical and mental loads. Mean BP reductions over all standardized loads was greater with cilazapril than placebo (-10 vs. -4.3 mm Hg, p < 0.05). These results show that BP is influenced similarly by mental and physical loads, and that behavior [i.e., awake state and non-rapid eye movement and rapid eye movement (NREM and REM) sleep determines BP regulation. Cilazapril is effective in reducing BP in all situations, especially during REM sleep hypertension.
Adult↗
Nocturnal hypertension and cardiovascular risk: consequences for diagnosis and treatment.
General use of ambulatory noninvasive 24-h blood pressure monitoring in many patients has shown that new criteria for arterial hypertension are useful. A classification of circadian blood pressure in "dippers" and "nondippers" (no physiologic drop of blood pressure) needs to be specified. An altered circadian blood pressure profile, like that in nondippers, was used as a diagnostic criterion for secondary hypertension. Recent epidemiologic studies in patients with essential hypertension have shown that nondippers are at higher risk for cardiovascular complications such as myocardial infarction and cerebrovascular insult. The studies also revealed that sleep-related breathing disorders (SRBD) are characterized by increased cardiovascular risk. Increases in blood pressure caused by SRBD could be documented, with the highest amount occurring during REM sleep. A study performed in a general practice showed a high incidence (40/112) of nondippers in a group of snoring middle-aged men with obesity and daytime fatigue. This indicates diagnostic and therapeutic consequences for the control of 24-h blood pressure, including nocturnal breathing pattern and daytime symptoms due to SRBD. The goal of antihypertensive drug therapy is to reduce blood pressure significantly during the day and during the night in different stages of wakefulness and sleep. A new protocol was designed to investigate blood pressure over 24 h under a standardized load, including nocturnal hypertension. The angiotensin-converting enzyme (ACE) inhibitor cilazapril was used in this test procedure and showed a significant and clinically relevant mean blood pressure reduction of 10.0 mm Hg (versus placebo 4.3 mm Hg) over 24 h.
Adult↗
A new method to study blood pressure, heart rate and EEG as a function of reaction time.
A new method is presented to study the relationship between reaction time and blood pressure, heart rate and EEG. The method consists of a simultaneous recording of continuous invasive or non-invasive arterial blood pressure, ECG, EEG, EMG and EOG in a sound-isolated chamber while a monotonous visual reaction time test is running for about 90 minutes. The signals are A/D-converted and analyzed digitally after recording. One second average amplitudes are computed. Systolic, mean and diastolic blood pressure values are calculated, and the EEG is divided into the delta, theta, alpha, sigma and beta frequency bands. The signal amplitudes are averaged in three different reaction time categories, i.e., when the reaction is normal, delayed or missing. Preliminary tests suggest that interesting differences can be observed in the studied variables in different reaction time classes. This method can also be applied to the investigation of autonomic control and to treatment studies.
Blood Pressure↗
[Spectral analysis of long-term blood pressure measurements in patients with sleep-related respiratory disorders].
Spectral analysis of long-term recordings of blood pressure is a convenient method to recognise and reveal the amplitude and periodicity of changes in blood pressure during sleep. The increased variability of nocturnal blood pressure in patients with sleep apnoea is mainly determined by two types of oscillating variations in blood pressure: 1. Oscillations in a low frequency range of 0.0-0.06 Hz associated with breathing disorders and consecutive arousals. 2. Oscillations in a higher frequency range of 0.2-0.5 Hz associated with three different patterns of breathing. Normal undisturbed breathing, regular snoring and ineffective breathing efforts during obstruction of the upper airways. Furthermore, the interaction between breathing or breathing disorder and arterial blood pressure is determined by the influence of the sleep stages.
Adult↗
[Non-invasive, continuous, portable blood pressure recording in the sleep laboratory].
The importance of cardiovascular consequences of sleep related breathing disorders implies the need for continuous recording of blood pressure in any cardiorespiratory polysomnography. Invasive techniques, which are the gold standard, are limited to special indications and studies. Non-invasive, continuous methods opened new possibilities for sleep laboratory investigations. The existing Finapres system proved to be a valuable method if parallel video recording was applied. The size of the system restricts its application to stationary settings only. Therefore the methodology was improved and integrated in a portable recorder. A prototype of this recorder, the Portapres, was validated against invasive pressure in 9 one-hour tests during the day and 12 polysomnographic recordings of 8 hours duration. The Portapres has now two finger cuffs and an automatic hydrostatic height compensation to overcome limitations of the Finapres. The technical implementation of the recorder needs more improvements. The correlation of mean blood pressure was 0.81 and mean pressure of the Portapres was 6.8 mmHg lower than invasive values.
Blood Pressure↗
Spectral analysis of blood pressure in patients with sleep-related breathing disorders during NREM and REM sleep.
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Humans↗
[Sleep-related respiratory disorders: early detection and follow-up by close patient contact].
Sleep apnoea (SA) ist a challenge to clinical research, since it occurs in up to 10% of the male professionally active population. It is indeed a challenge in respect of diagnosis, clinical aspects and therapy. SA is not only responsible for mental handicaps during daytime caused by disturbed sleep (increased tendency to doze or fall asleep, proneness to accidents), it will also enhance morbidity and mortality in aspect of cardiopulmonary and cardiovascular diseases (hypertension, cardiac insufficiency, disturbances of cardiac rhythm). All kinds of secondary and/or subsequent damage are reversible, provided diagnosis and rigidly introduced and maintained treatment have been performed well in time. SA can be diagnosed, treated and followed up by means of methods that can be flexibly employed outside the hospital, i.e. on an outpatient basis, such as questionnaires, MESAM IV, behavioural counselling, drug therapy). Within the framework of the current three-year project a stepwise concept was developed for diagnosis and treatment that also includes outpatient examination procedures. This system integrates anamnesis, outpatient monitoring, sleep laboratory, therapy and therapy control into a comprehensive feedback system of patient care. The following standardised procedural steps are included in the outpatient part of this system: baseline examination, treatment that can be performed on an outpatient basis, short-term, medium-term and long-term therapy follow-up. If these steps do not yield satisfactory results or if there is a high acute risk, the patient is subjected to in-patient treatment. At present, 683 first examinations and 420 follow-ups have been recorded.(ABSTRACT TRUNCATED AT 250 WORDS)
Adolescent↗
[Comparative use of MESAM IV and polysomnography in sleep-related respiratory disorders].
The high prevalence of sleep-related respiratory disturbances among the male population requires development of reliable outpatient measurement systems enabling the selection of patients to be admitted to the sleep laboratory. MESAM IV is such a system. It can record for up to 18 hours via four sensors a patient's snoring sounds, heart rate, oxygen saturation and posture. To test the reliability of the instrument we compared parallel night measurements by MESAM IV and polysomnography (PSG) via the respective Respiratory Disturbance Indices (RDI = number of apnoeas plus hypopnoeas per hour). The group of subjects studied numbered 68 patients of the sleep laboratory suspected of having sleep-related respiratory disturbances (age 18-78 years, average 50.8 yrs.; height 164-192 cm, av. 175.2 cm; weight 40-160 kg, av. 99.3 kg; body mass index 13.8-49.5, av. 32.3). Assessment of the MESAM measurements was effected on the one hand by means of a computer programme (version 1.2) that is part of the system, and on the other hand by 3 independent evaluators, two of whom were already experienced in MESAM evaluation. Each evaluator was unaware of all personal and clinical data of the patients and of the results obtained by the other evaluators. Visual assessment was performed according to fixed criteria with the inclusion of all four measurement signals of the system, whereas two mutually independent respiratory disturbance indices (RDI) were calculated by computer evaluation. The results of the various MESAM IV evaluations were compared with those of polysomnography.(ABSTRACT TRUNCATED AT 250 WORDS)
Adolescent↗
[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↗
[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↗