Sleep Laboratory

Sleep disorders are often underestimated with regard to cause and effect, because sleep-related breathing disorders usually always occur in association with serious chronic diseases such as heart deficiency, hypertension, stroke, atrial fibrillation and Type 2 diabetes.

Sleep-related breathing disorders not only impair the quality of sleep but are also of prognostic importance. We analyse such disorders by means of polysomnographic investigation in the Sleep Laboratory.

The HPK Sleep Laboratory

Despite increased vulnerability due to very limited responsiveness, sleep represents a period of pronounced rest, and serves for the regeneration of the organism. This was seen for a long time as a purely passive state and yet is a complex process, in which the neural network is partially highly active and nearly all bodily functions are greatly modulated over the various phases of wakefulness, dream sleep, light and deep sleep.
The diagnosis of the over 80 different sleep disorders is carried out by means of a polysomnographic examination in a sleep laboratory. The patient is continuously observed over 1-3 nights for brain activity (EEG) and various bodily functions such as heart rate, breathing movements and noises, muscle tension, eye movement, body position and temperature and oxygen saturation in the blood. All of the recorded values result in a very accurate sleep profile with regard to the respective stages of sleep and allows for reliable conclusions on the sleep disorder in question.
Sleep disorders can be traced back to individual organic, physiological, psychological or pharmacological factors, but are however very frequently the result of the interaction of different conditions and are very often associated with serious chronic diseases; these are referred to as multifactorial causes. The diagnosis of sleep disorders therefore requires an interdisciplinary approach. Diagnosis and treatment of sleep-related breathing disorders are provided by specific medical specialists and are covered by statutory health insurance.

Sleep-related breathing disorders and cardiovascular diseases

Patients with cardiac, pulmonary or metabolic co-morbidity can by treatment of the underlying disease benefit from therapy of the nocturnal sleep disorder and should be examined for sleep-related breathing disorders even on low clinical suspicion.
Sleep-related breathing disorders are a heterogeneous group of respiratory disorders, which among other things lead to an oxygen desaturation (hypoxia) of the organism. Very frequent but not essential main symptoms include excessive daytime sleepiness and snoring. While sleep-related respiratory disorders occur in around 2% to 4% of healthy women and men, patients who suffer from a cardiomyopathy (CMP) are significantly more likely to be affected. The nightly repetitive oxygen desaturations caused by night-time breathing disorder are linked to a high rate of mortality in these patients. The treatment of the sleep-related breathing disorders could represent an additive therapy approach to improve the prognosis for CMP. Depending on the pathogenesis, sleep-related breathing disorders are divided into obstructive and central events:

Obstructive sleep apnoea (OSA)

Obstructive events occur due to collapse of the upper respiratory channels during inspiration. This results in hypoxia with the following sympathetic activation: depending on the degree of oxygen desaturation, vasoconstriction occurs, accompanied by an increase in blood pressure (arterial hypertension). The continued inspiratory respiratory movements also lead to an increased wall tension in the left ventricle and thus a reduction of cardiac volume. In patients with symptomatic CMP and a left ventricular ejection line below 40%, obstructive events were confirmed at 12-37%.

Central sleep apnoea (CSA)

The exact prevalence of central sleep apnoea within the general population is unknown, although central events have been confirmed in 21-40% of patients with symptomatic CMP and a left ventricular ejection line below 40%. Central events are characterized by a disturbed respiratory drive, by which the control loop of respiration evokes an interplay of hyper- and hypoventilation, to the point of central apnoea. Central events are considered as a consequence of a CMP, but could also lead to a progression of heart deficiency. The occurrence of central events is associated with a poor prognosis. Interestingly a nightly shift from obstructive to central events can be observed in CMP patients.
The therapy of sleep-related breathing disorders improves the prognosis of the underlying co-morbid disease. The common link between sleep apnoea and cardiovascular disease (e.g., heart deficiency or hypertension) seems to be the activation of the sympathetic tone, which among other things can lead to an increase in blood pressure as a result of sleep-related breathing disorder. Interestingly about 20% of patients with heart deficiency also suffer from type 2 diabetes, and approximately 30-40% of heart deficiency patients in addition exhibit renal failure, which in turn is associated with a significantly higher mortality. It has not yet been definitively determined whether there is a direct causal relationship between the diseases or whether this is due to a superordinate phenomenon.
Conclusion: The underlying disease and sleep-related breathing disorders seem to deteriorate not only over their course; on the other hand, basic therapy of the underlying disease and treatment of the nocturnal breathing disorder have a positive effect on each other, with an improved prognosis for the patient. This has already been successfully demonstrated on heart deficiency as well as renal failure patients. Sleep-related breathing disorders should therefore always be considered and treated in connection with other possible chronic conditions such as heart or kidney disease, diabetes or a COPD.

The polysomnographic examination in the Sleep Laboratory

Respiratory interruptions in the night, the so-called sleep apnoea syndrome, lead to a decrease in the oxygen saturation of the blood and to an increase in blood pressure with an increased risk of heart attack and stroke. Patients suffering from a chronic cardiac, pulmonary or metabolic disease in particular should be examined for sleep-related breathing on observation of the main symptoms of sleep apnoea syndrome such as daytime sleepiness, sudden tendency to sleep during the day ("nodding off"), concentration deficiencies and snoring.
Sleep disorders are among the frequent complaints. About 25% of the population complain of sleep disorders, 11% experiencing their sleep as "often not relaxing". Although not everyone who suffers from sleep disorders needs to undergo sleep medicine examination in the sleep laboratory, patients who suffer from a chronic underlying disease, which is often associated with sleep-related breathing disorders, should in particular be examined in this regard.
The diagnosis of sleep disorders, and in particular of sleep-related breathing disorders, takes place following a detailed initial discussion during the consultation, in which the health status, as well as the complaints of the patient are determined, initially as an out-patient. The patient receives the mobile recording equipment for the polysomnographic examination, and detailed instructions on how to attach the sensors. He then sleeps at home in his familiar environment. This is followed by evaluation and discussion with the sleep specialist. By means of various sensors, the device records certain biological parameters and functions of the body such as the oxygen content of the blood, brain activity (EEG) and heart rate, breathing movements and noises, muscle tension, eye movements etc. The examination can then be supplemented if necessary by a partly in-patient stay in the sleep laboratory.
The "Deutsche Gesellschaft für Schlafforschung und Schlafmedizin" (DGSM) (German Association for Sleep Research and Sleep Medicine) has determined the following indications for a referral of a patient to a sleep laboratory:
- Severe sleep disorders with significant sensory disability and/or performance capability during the day
- Chronic and intractable sleep disorders with negative treatment success for more than half a year
- Urgent suspicion of an organically-related sleep disorder (e.g., sleep apnoea syndrome, heart rhythm disorders, epilepsy etc.)
- Conspicuous behaviour of unclear cause during sleep (e.g. parasomnia)
- Patients with high psychological stress in a diagnostic and/or therapeutic service of the Sleep Medicine Centre geared to their complaint
- Intractable sleep disorders with co-morbidity of physical or psychological disorders that probably interact with the sleep disorder

Polysomnography at the HPK

The Heidelberg Practice Clinic for Cardiology has since recently operated its own sleep laboratory with state-of-the-art screening devices, which is run under the direction of Mrs. Becker, in collaboration with Dr. med. Mohammad Natour, Specialist in Cardiology at the HPK.
Both specialists have corresponding experience in the field of the modern sleep medicine. In addition to the differentiated diagnosis and analysis of the nocturnal sleep problem, individual therapies are also offered at the HPK. The sleep laboratory is also available for referral of patients of colleagues in other disciplines such as ENT, (cardio) pulmology and internal medicine, neurology and psychiatry to the money transfer. The sleep laboratory is not only technically well equipped, but also offers a pleasant sleeping atmosphere in attractive rooms.
If you are interested in further information or in an examination, please call our practice team on 06221-434 14-0.