Sleep, 15:S9-S12 © 1992 American Sleep Disorders Association and Sleep Research Society
Ambulatory Diagnosis of Sleep-Related Breathing Disorders T. Penzel and J. H. Peter Medizinische Poliklinik der Philipps-Universitat, Zeitreihenlabor, Baldingerstrafie 1, D-3550 Marburg, Germany
Summary: Ambulatory diagnosis of sleep-related breathing disorders (SRBD) is necessary due to their high prevalence and to the limited capacities of sleep centers. Categories ofSRBD 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. Key Words: Ambulatory monitoring-Sleep-related breathing disorders-Obstructive sleep apnea.
The prevalence of sleep-related breathing disorders (SRBD) and the possibility for successful therapeutic intervention have prompted an increased interest in developing systems for early recognition ofSRBD. Fully developed clinical sleep apnea and hypoventilation syndromes can be easily recognized by their clinical symptoms and by using specific anamnestic criteria, so that patients can be admitted to centers specializing in diagnosis and treatment of these sleep disorders. Experience shows, however, that most affected patients do not exhibit all of the symptoms of these syndromes. Because many patients are affected by SRBD and Europe still has few sleep laboratories, it is not possible to admit all those patients into a sleep center who exhibit anamnestic and clinical suspicion ofSRBD but in whom no clinical symptoms or current or mid-term risk due to the disease are evident (1). Experience shows, however, that this particular group of patients profits from an early diagnostic categorization of their problem. Early diagnosis and selection of the necessary therapeutical steps provides the best chance of success. The most important field of application for ambulatory systems designed to diagnose SRBD are functional disorders that are associated with SRBD. SRBD can be assessed by a combination of clinical examination and anamnesis as well as high-technological
measurement in the sleep lab. This allows clarification of the diagnostic suspicion, a better evaluation of the risk profile of the patient and the correct formulation of the sleep laboratory examination. The long-term observation of previously diagnosed patients can also be supplemented with such systems.
Categories of SRBD
Today, sleep related breathing disorders are divided into two practical categories: SRBD with obstruction ofthe upper airway and SRBD without obstruction of the upper airway (2), Obstructive snoring and obstructive apnea are SRBD with obstruction of the upper airway. Both can also occur combined with hypoventilation and are the constituting patterns for the obstructive sleep apnea syndrome. The main symptoms of obstructive sleep apnea syndrome are loud and irregular snoring and increased daytime fatigue and sleepiness. Nocturnal cessations of breathing reported by a second party, restless sleep, a feeling of exhaustion and headache in the morning and the reduction of mental efficiency also occur frequently. Depression and impotence are also frequent symptoms. Internal diseases that are often associated with SRBD are adipositas, arterial hypertension, cardiac arrhythmias, pulmonary hypertension, cardiomegaly and polyglobuly. Accepted for publication July 1992. The clinical symptoms of the so-called central apnea Address correspondence and reprint requests to t. Penzel, Medizinische Poliklinik cler Philipps-Universitat, Zeitreihenlabor, Baldin- syndrome, which is characterized by a lack of breathing impetus and absence of diaphragm activity; corregerstra13e 1, D-3550 Marburg, Germany.
S9 Downloaded from https://academic.oup.com/sleep/article-abstract/15/suppl_6/S9/2749371 by guest on 23 May 2018
SlO
T. PENZEL AND J. H. PETER
spond to those of obstructive sleep apnea, with the exception of snoring. Hypoventilation syndromes such as the so-called primary alveolar hypo ventilation syndrome or the secondary alveolar hypoventilation syndrome (in muscular-skeletal, neuromuscular, cerebral, pneumologic or cardio-vascular illnesses) are characterized by a rapid progradient right heart insufficiency; flat, panting breathing during the night; occasional awakening with a feeling of suffocation and/or headaches; morning headaches, and daytime sleepiness. The prognoses of untreated hypoventilation syndromes are very poor. However, with early diagnosis these patients can now be successfully treated using nasal ventilation programs. The diagnosis of nocturnal hyperventilation, unlike apnea syndromes, can be substantiated with relative certainty using a simple ambulatory recording technique, pulsoximetry.
tional occurrence of SRBD, it is of great importance to recognize the possible presence of this additional risk. Finally, an indication for ambulatory recording is also given in all patients without known apnea-specific symptoms who do, however, show findings that could be related to SRBD (for example polyglobuly, global heart insufficiency, right heart insufficiency of unknown origin or predominantly nocturnal heart rhythm disorders). Systems
A few years ago, technical factors limited the use of ambulatory systems (5,6). Today, however, the main technological problems in sensor technology, amplification technology, recording and playback of data appear to be solved (Fig. I). In principle, a system such as the multichannel Oxford Medilog MPA recorder is able to record all noninvasive functions under ambulatory conditions with the same accuracy as an exIndications amination in the sleep laboratory (7). Also, with solidDifferent functional disorders and diseases in many state memory-based systems such as the Vitalog home fields can indicate an ambulatory examination for a monitoring system HMS-5000 (8), it can be expected sleep-related breathing disorder (3,4): for example, mal,e that the current limits in recording data will soon be potency disorders in the field of andrology; hypothy- improved so that sufficient amounts of data can be reosis, acromegalia and adipositas permagna in en- recorded with a density of recording and storage cadocrinology; polyglobuly in hematology; obstruction pacity comparable to stationary laboratory systems. of the upper airway visible during waking state in the For ambulatory systems, however, it is true that adefield of ENT; nocturnal cardiac arrhythmias; essential quate evaluation of recordings is only guaranteed if the hypertension, heart insufficiency of unknown origin, raw data (i.e. the breathing curve, oxygen saturation, dilatative cardiomyopathy in cardiology; neuromus- heart rate or other recorded signals) can be recorded cular diseases, hypersomnia, hyposomnia and lack of and played back with the complete course of the curve intellectual capability in neurology and psychiatry; cy- (l). High resolution of the waveform of the signals is phoscoliosis in orthopedia; children with development necessary to facilitate a clear indication. The single, disorders, children with large tonsils and adenoids in and thereby uncontrollable, recording or playback of pediatrics; hypoxy and/or hypercapny with or without results or calculated indices without the original wave previous lung diseases, right heart insufficiency or glob- cannot be accepted, since no unified obligatory stanal heart insufficiency of unknown origin in pulmon- dards for their evaluation exist, even for stationary ology; unclear "states of failure" in psychosomatics; conditions. In order to fulfill the demands on the signal quality, and craniofacial malformation in tooth, mouth and the signals must be digitalized and recorded with a maxillofacial surgery. Thus, the spectrum of indications for ambulatory sufficiently high sampling rate, i.e. with at least twice monitoring is not limited by the epidemiologically ori- the frequency of the highest-occurring signal frequency. ented area of screening or field studies on volunteers In recording respiration, each breath must be recognot exhibiting specific, conspicuous symptoms that nizable. In slow changing signals such as oxygen sathave not yet been clinically registered. The indications uration and body temperature, a value should be rein patients with the typical combination of clinical corded at a minimum of every 2 seconds. Heart rate findings for SRBD are more concerned with limiting should be recorded beat to beat, at least once per secthe current individual risk or observing its develop- ond. A resolution of I second also applies to the meament. In patients with symptoms that indicate SRBD surements from other biosignals, such as delta- and (for example, daytime sleepiness or loud and irregular alpha-power of the electroencephalogram (EEG), snoring), the emphasis is on the clarification of these movement intensity from the actogram and systolic, symptoms. In patients with known cardiological, pneu- diastolic and mean blood pressure from the blood presmological, neurological or muscular-skeletal diseases sure curve. The condition for all these values is a prewho would be particularly endangered by the addi- vious correct evaluation using appropriate algorithms. Sleep, Vol. 15, No.6, 1992 Downloaded from https://academic.oup.com/sleep/article-abstract/15/suppl_6/S9/2749371 by guest on 23 May 2018
:~
..
AMBULATORY DIAGNOSIS OF SRBD
Function
Parameter
Respiratory
Flow (thermistor) Ratio flow/effort (thermistor, inductive plethysmography) Snoring Oxygen saturation EKG/heart rate Arterial blood pressure (photofingerplethysmography) EOG/actiokulogram Integrated EMG Delta-power Heart rate Integrated EMG Movement/position sensor
Cardiovascular
~'
.-
., .,.
(
>.
Sleep/wake
Movement
Vitalog Medilog HMS 5000 MPAII
SII
SCSB
Somnolog
X X
X X
X X X
X X
X
X X X X X X
X X X X X X
X X X X X X
+ Sa02 MESAM IV cm 102 Portapres
X X
X X
X X X
X X X
X
X
X
X
X
X X
X
FIG. 1. An overview of the multichannel ambulatory recording systems available in Europe. These systems with high resolution and complete playback of the recorded data usually provide information on respiration using snoring or oronasal thermistor and on oxygen saturation. It should be noted that an exclusive study of the respiratory parameter can only be made with a system that records respiratory flow and effort along with saturation. Two examples that work with thermistors and inductive plethysmography are the Oxford system or the Vitalog system. To evaluate sleep with a high degree of certainty, only the Oxford system is presently suitable for an exclusive study. Heart rate, movement and position sensors are the biosignals most commonly used in addition in small compact systems .
Mean values of 10 or even 60 seconds do not do justice to the rapidly changing signals in sleep and therefore are useless. Only the results of computer-based analysis of ambulatory recordings can be useful for documentation. They must also be correlatable and controllable using the original raw data, particularly in order to exclude false-negative findings. All sleep-wake parameters, whether delta power or other integrated measures, require a resolution of at least 1 second. The same goes for movement parameters, if they are recorded by integrated electromyogram (EM G) derivations or other high-resolution sensors. The ambulatory system must be attached to the patient by specially trained technicians. The documentation of the final clinical results must include the system used to gain the results. With respect to functions and malfunctions, the concept must take into consideration which biosignals are relevant. For breathing, with its malfunction obstruction of the upper airways and hypoventilation, the necessary biosignals are airflow and respiratory effort. To control the effect of respiratory effort, one must measure the blood gases (p02, O 2 saturation and pC0 2) and pH. For the cardiovascular system the malfunctions are cardiac arrhythmias in the signal electrocardiogram (EKG) and arterial hypertension as obtained by continuous bloodpressure recording. The biosignals of movement and EMG are related to the malfunctions of periodic movement. The biosignals relevant in the context ofa central nervous activation reaction (movement arousal) are movement and body position, EMG activity and momentary heart rate. With respect to sleep/wake disorders or sleep and/or wake disorders, it is necessary to record sleep stages or dynamic changes
in sleep and daytime vigilance. Furthermore, sleep fragmentation through central nervous activation reaction (arousal) and sleep change must be recorded. The related biosignals of these phenomena are EEG, electrooculogram (EOG), EMG, EKG and momentary heart rate. In many cases, the presence of an SRBD can be documented with a simple one-channel, long-term recording system such as holter EKG or long-term blood pressure measurement, actigraphy or pulsoximetry. Many different pulsoximeters, long-term EKG recorders, actigraphs and long-term blood pressure recorders are commercially available. Recently, a portable, noninvasive continuous blood pressure recorder (Portapres, Stimotron) was also introduced (8). In our experience, its recordings not only allow for an adequate diagnosis of nocturnal hypertension but also provide information on the type and nature of the combination of damages to cardiovascular function in SRBD and other sleep disorders.
REFERENCES I. Guilleminault C, Partinen M, Penzel T, et al. Technical issues related to obstructive sleep apnea syndrome. In: Guilleminault C, Partinen M, eds. Obstructive sleep apnea syndrome: clinical research and treatment. New York: Raven Press, 1990, pp. 183207. 2. Peter JH, Becker H, Blanke J, et al. Empfeh1ungen zur Diagnostik, Therapie und Langzeitbetreuung von Patienten mit Sch1afapnoe. Medizinische Klinik 1991 ;86:46-50. 3. Peter JH, Blanke J, Cassel W, et al. Richt1inien zur ambu1anten Diagnostik der Sch1afapnoe. Medizinische Klinik 1992;87 (in press). 4. Peter JH, Penzel T. Portable monitoring of sleep and breathing. In: Saunders N, Sullivan C, eds. Sleep and breathing, 2nd ed. New York: Dekker, 1992 (in press). Sleep, Vol. 15, No.6, 1992
Downloaded from https://academic.oup.com/sleep/article-abstract/15/suppl_6/S9/2749371 by guest on 23 May 2018
S12
T. PENZEL AND J. H. PETER
5. Penzel T. Ambulatory patient monitoring in the diagnosis of sleep disorders. In: Amlaner e, ed. Biotelemetry X, Proceedings of 10th International Symposium on Biotelemetry. Fayetteville, AR: University of Arkansas Press, 1989:565-73. 6. Broughton RJ. Ambulant home monitoring of sleep and its disorders. In: Kryger MR, Roth T, Dement we, eds. Principles and practice ofsleep medicine. Philadelphia: Saunders, 1989, pp. 696·701.
7. Kayed K. The present state of ambulatory monitoring of sleep. In: Peter JR, Penzel T, Podszus T, von Wichert P, eds. Sleep and health risk. Berlin: Springer, 1991, pp. 3-10. 8. Miles LE, Broughton RJ, eds. Medical monitoring in the home and work environment. New York: Raven Press, 1990.
..
..
Sleep. Vol. 15. No.6. 1992 Downloaded from https://academic.oup.com/sleep/article-abstract/15/suppl_6/S9/2749371 by guest on 23 May 2018
Ambulatory Diagnosis of Sleep-Related Breathing Disorders T. Penzel and J. H. Peter Medizinische Poliklinik der Philipps-Universitat, Zeitreihenlabor, Baldingerstrafie 1, D-3550 Marburg, Germany
Summary: Ambulatory diagnosis of sleep-related breathing disorders (SRBD) is necessary due to their high prevalence and to the limited capacities of sleep centers. Categories ofSRBD 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. Key Words: Ambulatory monitoring-Sleep-related breathing disorders-Obstructive sleep apnea.
The prevalence of sleep-related breathing disorders (SRBD) and the possibility for successful therapeutic intervention have prompted an increased interest in developing systems for early recognition ofSRBD. Fully developed clinical sleep apnea and hypoventilation syndromes can be easily recognized by their clinical symptoms and by using specific anamnestic criteria, so that patients can be admitted to centers specializing in diagnosis and treatment of these sleep disorders. Experience shows, however, that most affected patients do not exhibit all of the symptoms of these syndromes. Because many patients are affected by SRBD and Europe still has few sleep laboratories, it is not possible to admit all those patients into a sleep center who exhibit anamnestic and clinical suspicion ofSRBD but in whom no clinical symptoms or current or mid-term risk due to the disease are evident (1). Experience shows, however, that this particular group of patients profits from an early diagnostic categorization of their problem. Early diagnosis and selection of the necessary therapeutical steps provides the best chance of success. The most important field of application for ambulatory systems designed to diagnose SRBD are functional disorders that are associated with SRBD. SRBD can be assessed by a combination of clinical examination and anamnesis as well as high-technological
measurement in the sleep lab. This allows clarification of the diagnostic suspicion, a better evaluation of the risk profile of the patient and the correct formulation of the sleep laboratory examination. The long-term observation of previously diagnosed patients can also be supplemented with such systems.
Categories of SRBD
Today, sleep related breathing disorders are divided into two practical categories: SRBD with obstruction ofthe upper airway and SRBD without obstruction of the upper airway (2), Obstructive snoring and obstructive apnea are SRBD with obstruction of the upper airway. Both can also occur combined with hypoventilation and are the constituting patterns for the obstructive sleep apnea syndrome. The main symptoms of obstructive sleep apnea syndrome are loud and irregular snoring and increased daytime fatigue and sleepiness. Nocturnal cessations of breathing reported by a second party, restless sleep, a feeling of exhaustion and headache in the morning and the reduction of mental efficiency also occur frequently. Depression and impotence are also frequent symptoms. Internal diseases that are often associated with SRBD are adipositas, arterial hypertension, cardiac arrhythmias, pulmonary hypertension, cardiomegaly and polyglobuly. Accepted for publication July 1992. The clinical symptoms of the so-called central apnea Address correspondence and reprint requests to t. Penzel, Medizinische Poliklinik cler Philipps-Universitat, Zeitreihenlabor, Baldin- syndrome, which is characterized by a lack of breathing impetus and absence of diaphragm activity; corregerstra13e 1, D-3550 Marburg, Germany.
S9 Downloaded from https://academic.oup.com/sleep/article-abstract/15/suppl_6/S9/2749371 by guest on 23 May 2018
SlO
T. PENZEL AND J. H. PETER
spond to those of obstructive sleep apnea, with the exception of snoring. Hypoventilation syndromes such as the so-called primary alveolar hypo ventilation syndrome or the secondary alveolar hypoventilation syndrome (in muscular-skeletal, neuromuscular, cerebral, pneumologic or cardio-vascular illnesses) are characterized by a rapid progradient right heart insufficiency; flat, panting breathing during the night; occasional awakening with a feeling of suffocation and/or headaches; morning headaches, and daytime sleepiness. The prognoses of untreated hypoventilation syndromes are very poor. However, with early diagnosis these patients can now be successfully treated using nasal ventilation programs. The diagnosis of nocturnal hyperventilation, unlike apnea syndromes, can be substantiated with relative certainty using a simple ambulatory recording technique, pulsoximetry.
tional occurrence of SRBD, it is of great importance to recognize the possible presence of this additional risk. Finally, an indication for ambulatory recording is also given in all patients without known apnea-specific symptoms who do, however, show findings that could be related to SRBD (for example polyglobuly, global heart insufficiency, right heart insufficiency of unknown origin or predominantly nocturnal heart rhythm disorders). Systems
A few years ago, technical factors limited the use of ambulatory systems (5,6). Today, however, the main technological problems in sensor technology, amplification technology, recording and playback of data appear to be solved (Fig. I). In principle, a system such as the multichannel Oxford Medilog MPA recorder is able to record all noninvasive functions under ambulatory conditions with the same accuracy as an exIndications amination in the sleep laboratory (7). Also, with solidDifferent functional disorders and diseases in many state memory-based systems such as the Vitalog home fields can indicate an ambulatory examination for a monitoring system HMS-5000 (8), it can be expected sleep-related breathing disorder (3,4): for example, mal,e that the current limits in recording data will soon be potency disorders in the field of andrology; hypothy- improved so that sufficient amounts of data can be reosis, acromegalia and adipositas permagna in en- recorded with a density of recording and storage cadocrinology; polyglobuly in hematology; obstruction pacity comparable to stationary laboratory systems. of the upper airway visible during waking state in the For ambulatory systems, however, it is true that adefield of ENT; nocturnal cardiac arrhythmias; essential quate evaluation of recordings is only guaranteed if the hypertension, heart insufficiency of unknown origin, raw data (i.e. the breathing curve, oxygen saturation, dilatative cardiomyopathy in cardiology; neuromus- heart rate or other recorded signals) can be recorded cular diseases, hypersomnia, hyposomnia and lack of and played back with the complete course of the curve intellectual capability in neurology and psychiatry; cy- (l). High resolution of the waveform of the signals is phoscoliosis in orthopedia; children with development necessary to facilitate a clear indication. The single, disorders, children with large tonsils and adenoids in and thereby uncontrollable, recording or playback of pediatrics; hypoxy and/or hypercapny with or without results or calculated indices without the original wave previous lung diseases, right heart insufficiency or glob- cannot be accepted, since no unified obligatory stanal heart insufficiency of unknown origin in pulmon- dards for their evaluation exist, even for stationary ology; unclear "states of failure" in psychosomatics; conditions. In order to fulfill the demands on the signal quality, and craniofacial malformation in tooth, mouth and the signals must be digitalized and recorded with a maxillofacial surgery. Thus, the spectrum of indications for ambulatory sufficiently high sampling rate, i.e. with at least twice monitoring is not limited by the epidemiologically ori- the frequency of the highest-occurring signal frequency. ented area of screening or field studies on volunteers In recording respiration, each breath must be recognot exhibiting specific, conspicuous symptoms that nizable. In slow changing signals such as oxygen sathave not yet been clinically registered. The indications uration and body temperature, a value should be rein patients with the typical combination of clinical corded at a minimum of every 2 seconds. Heart rate findings for SRBD are more concerned with limiting should be recorded beat to beat, at least once per secthe current individual risk or observing its develop- ond. A resolution of I second also applies to the meament. In patients with symptoms that indicate SRBD surements from other biosignals, such as delta- and (for example, daytime sleepiness or loud and irregular alpha-power of the electroencephalogram (EEG), snoring), the emphasis is on the clarification of these movement intensity from the actogram and systolic, symptoms. In patients with known cardiological, pneu- diastolic and mean blood pressure from the blood presmological, neurological or muscular-skeletal diseases sure curve. The condition for all these values is a prewho would be particularly endangered by the addi- vious correct evaluation using appropriate algorithms. Sleep, Vol. 15, No.6, 1992 Downloaded from https://academic.oup.com/sleep/article-abstract/15/suppl_6/S9/2749371 by guest on 23 May 2018
:~
..
AMBULATORY DIAGNOSIS OF SRBD
Function
Parameter
Respiratory
Flow (thermistor) Ratio flow/effort (thermistor, inductive plethysmography) Snoring Oxygen saturation EKG/heart rate Arterial blood pressure (photofingerplethysmography) EOG/actiokulogram Integrated EMG Delta-power Heart rate Integrated EMG Movement/position sensor
Cardiovascular
~'
.-
., .,.
(
>.
Sleep/wake
Movement
Vitalog Medilog HMS 5000 MPAII
SII
SCSB
Somnolog
X X
X X
X X X
X X
X
X X X X X X
X X X X X X
X X X X X X
+ Sa02 MESAM IV cm 102 Portapres
X X
X X
X X X
X X X
X
X
X
X
X
X X
X
FIG. 1. An overview of the multichannel ambulatory recording systems available in Europe. These systems with high resolution and complete playback of the recorded data usually provide information on respiration using snoring or oronasal thermistor and on oxygen saturation. It should be noted that an exclusive study of the respiratory parameter can only be made with a system that records respiratory flow and effort along with saturation. Two examples that work with thermistors and inductive plethysmography are the Oxford system or the Vitalog system. To evaluate sleep with a high degree of certainty, only the Oxford system is presently suitable for an exclusive study. Heart rate, movement and position sensors are the biosignals most commonly used in addition in small compact systems .
Mean values of 10 or even 60 seconds do not do justice to the rapidly changing signals in sleep and therefore are useless. Only the results of computer-based analysis of ambulatory recordings can be useful for documentation. They must also be correlatable and controllable using the original raw data, particularly in order to exclude false-negative findings. All sleep-wake parameters, whether delta power or other integrated measures, require a resolution of at least 1 second. The same goes for movement parameters, if they are recorded by integrated electromyogram (EM G) derivations or other high-resolution sensors. The ambulatory system must be attached to the patient by specially trained technicians. The documentation of the final clinical results must include the system used to gain the results. With respect to functions and malfunctions, the concept must take into consideration which biosignals are relevant. For breathing, with its malfunction obstruction of the upper airways and hypoventilation, the necessary biosignals are airflow and respiratory effort. To control the effect of respiratory effort, one must measure the blood gases (p02, O 2 saturation and pC0 2) and pH. For the cardiovascular system the malfunctions are cardiac arrhythmias in the signal electrocardiogram (EKG) and arterial hypertension as obtained by continuous bloodpressure recording. The biosignals of movement and EMG are related to the malfunctions of periodic movement. The biosignals relevant in the context ofa central nervous activation reaction (movement arousal) are movement and body position, EMG activity and momentary heart rate. With respect to sleep/wake disorders or sleep and/or wake disorders, it is necessary to record sleep stages or dynamic changes
in sleep and daytime vigilance. Furthermore, sleep fragmentation through central nervous activation reaction (arousal) and sleep change must be recorded. The related biosignals of these phenomena are EEG, electrooculogram (EOG), EMG, EKG and momentary heart rate. In many cases, the presence of an SRBD can be documented with a simple one-channel, long-term recording system such as holter EKG or long-term blood pressure measurement, actigraphy or pulsoximetry. Many different pulsoximeters, long-term EKG recorders, actigraphs and long-term blood pressure recorders are commercially available. Recently, a portable, noninvasive continuous blood pressure recorder (Portapres, Stimotron) was also introduced (8). In our experience, its recordings not only allow for an adequate diagnosis of nocturnal hypertension but also provide information on the type and nature of the combination of damages to cardiovascular function in SRBD and other sleep disorders.
REFERENCES I. Guilleminault C, Partinen M, Penzel T, et al. Technical issues related to obstructive sleep apnea syndrome. In: Guilleminault C, Partinen M, eds. Obstructive sleep apnea syndrome: clinical research and treatment. New York: Raven Press, 1990, pp. 183207. 2. Peter JH, Becker H, Blanke J, et al. Empfeh1ungen zur Diagnostik, Therapie und Langzeitbetreuung von Patienten mit Sch1afapnoe. Medizinische Klinik 1991 ;86:46-50. 3. Peter JH, Blanke J, Cassel W, et al. Richt1inien zur ambu1anten Diagnostik der Sch1afapnoe. Medizinische Klinik 1992;87 (in press). 4. Peter JH, Penzel T. Portable monitoring of sleep and breathing. In: Saunders N, Sullivan C, eds. Sleep and breathing, 2nd ed. New York: Dekker, 1992 (in press). Sleep, Vol. 15, No.6, 1992
Downloaded from https://academic.oup.com/sleep/article-abstract/15/suppl_6/S9/2749371 by guest on 23 May 2018
S12
T. PENZEL AND J. H. PETER
5. Penzel T. Ambulatory patient monitoring in the diagnosis of sleep disorders. In: Amlaner e, ed. Biotelemetry X, Proceedings of 10th International Symposium on Biotelemetry. Fayetteville, AR: University of Arkansas Press, 1989:565-73. 6. Broughton RJ. Ambulant home monitoring of sleep and its disorders. In: Kryger MR, Roth T, Dement we, eds. Principles and practice ofsleep medicine. Philadelphia: Saunders, 1989, pp. 696·701.
7. Kayed K. The present state of ambulatory monitoring of sleep. In: Peter JR, Penzel T, Podszus T, von Wichert P, eds. Sleep and health risk. Berlin: Springer, 1991, pp. 3-10. 8. Miles LE, Broughton RJ, eds. Medical monitoring in the home and work environment. New York: Raven Press, 1990.
..
..
Sleep. Vol. 15. No.6. 1992 Downloaded from https://academic.oup.com/sleep/article-abstract/15/suppl_6/S9/2749371 by guest on 23 May 2018
