[Stability of lung function parameters: spirometry, body plethysmography and mouth occlusion pressure (p0.1)]. / Zur Stabilität lungenfunktionsanalytischer Parameter: Spirometrie, Bodyplethysmographie und Mundverschlussdruck (P0.1).

Spirometric, bodyplethysmographic and mouth occlusion results of 9 healthy probands were measured 9 - 11 times over a total of 28 - 39 days. Interindividual predicted values based on large studies show SDs of +/- 20 %, which is not acceptable for the judgement of individual values. Individual values are much less scattered (SD +/- 10 %). Each test person showed a differing individual range of 75 - 140 %. Functional basic facts can be derived from the different levels of individual values. Early changes in the individual range are of special interest. For the evaluation of individual results the earliest possible basic values are of importance.

[Estimation of accident risk in obstructive sleep apnea syndrome (OSAS) by driving simulation]. / Abschätzung des Unfallrisikos bei obstruktivem Schlafapnoe-Syndrom (OSAS) durch Fahrsimulation.

Abstract. Patients with obstructive sleep apnea syndrome (OSAS) have an accident rate between two and seven times higher than normals. Investigations on accident frequency are based on case history, insurancy reports, and driving simulator investigations. The present controlled study was planned to test whether an increased accident risk could be demonstrated in patients with OSAS before and on CPAP (continuous positive airway pressure)-therapy using the driving simulator C.A.R. Driving simulator performance was investigated in 31 patients with polysomnographically confirmed OSAS (apnea-hypopnea-index 24.8 +/- 21.5/h) before, 2 and 42 days after initiation of CPAP and was compared to 10 healthy controls in whom OSAS was excluded by polysomnography. Driving simulator performance was significantly worse in OSAS as compared to normals especially in terms of accident frequency (OSAS: 2.7 +/- 2.0, controls: 1.3 +/- 1.5, p < 0.05) and concentration faults (OSAS: 12.4 +/- 5.1, controls: 7.1 +/- 3.2, p < 0.01). On CPAP accident frequency (OSAS before therapy: 12.4 +/- 5.1, 2 days CPAP: 1.5 +/- 1.4, p < 0.01; 42 days CPAP: 0.9 +/- 1.3, p < 0.001) and frequency of concentration faults (OSAS before therapy: 12.4 +/- 5.1, 2 days CPAP: 6.5 +/- 3.9, p < 0.001; 42 days CPAP: 4.9 +/- 3.3, p < 0.001) could be lowered significantly both in the short and medium term of therapy. The driving simulator C.A.R. is an adequate tool for the evaluation of an increased accident risk in OSAS-patients and demonstrates the efficiency of CPAP-therapy.

Breathing and locomotion in patients with Parkinson's disease.

The phase relationship between respiration and locomotion was examined in ten patients with Parkinson's disease (PD, mean age 65, range 51-79 years) and in six healthy subjects (mean age 63, range 58-68 years). Locomotion was measured by means of pressure sensors attached below the subjects' feet. Respiration was measured using respiratory inductive plethysmography. The data were recorded with a battery-driven portable device. We determined the coordination degree as the portion of steps which occurred within 12/50 bins of the respiratory cycle. The mean degree of coordination of PD patients was 45.0%+/-11.9%, for the healthy subjects 85.1%+/-10.8% (P<0.001). Three healthy subjects showed a 2:1 ratio between step and breathing rate, three a 3:2 ratio. Two PD patients showed a coordination of 4:1 and 3:1, respectively, with a larger scatter than in controls. In the other eight patients steps were almost equally distributed over the entire respiratory cycle. We conclude that in patients with PD the coordination between locomotion and breathing is reduced.

[Sleep-phase-related home therapy in congenital central hypoventilation syndrome (CCHS)]. / Schlafphasenbezogene Atemtherapie bei Kindern mit angeborener Unempfindlichkeit für CO2.

PATIENTS AND METHOD: Eight children with congenital central hypoventilation syndrome (CCHS) (aged 3 to 16 years) underwent repeated polysomnographic recordings (sleep-EEG, induction plethysmography, PtcO2, PtcCO2, PACO2, FO2, SaO2, ECG) during spontaneous breathing and during therapy. The result led to individual therapeutic plans. RESULT: During NREM sleep a close relationship between increasing EEG-delta-activity and increasing PCO2 could be observed (PCO2 max. 107 mm Hg in NREM IV). A similar effect was seen during mechanical ventilation with decreasing spontaneous respiratory activity during increasing sleep depth (PCO2 max. 89 mm Hg in NREM IV). Associated with NREM I/II and REM sleep strong variations in spontaneous breathing with consecutive variations of blood gases were observed. Hyperventilation during REM sleep (PCO2 min. 20 mm Hg) could occur with continuous mechanical ventilation. A continuous blood gas monitoring improved home therapy since blood gas adapted control of mechanical ventilation was possible now. This caused a stabilization of blood gases in sleep. CONCLUSION: Patients with CCHS show a vigilance-dependent, enlarged variability of blood gases which should be considered in the management of home therapy. Continuous monitoring and blood gas adapted mechanical ventilation obtain a stabilization of acid-base balance during sleep. Preliminary data suggest a positive effect on sleep-wake quality and mental performance.

[From tracheostomy to non-invasive mask ventilation: a study in children with congenital central hypoventilation syndrome]. / Vom Tracheostoma zur nasalen Maskenbeatmung--Erfahrungen bei Kindern mit zentralem Hypoventilationssyndrom.

BACKGROUND: Children with congenital central hypoventilation syndrome (CCHS) have to be ventilated during sleep due to respiratory insensitivity to CO2. This long-term mechanical ventilation sometimes requires a tracheostomy during infancy, leading to increased risk of infections and of tracheal problems, and later on to stigmatization and restrictions in social life. PATIENTS AND METHOD: We therefore evaluated non-invasive mask ventilation in 4 children between 6 and 15 years of age, who had been ventilated via tracheal canula since early infancy under polysomnographic control. RESULTS: Best results were obtained with standard face masks in connection with pressure controlled timed ventilation. In 1 child we used a volume-controlled ventilator. The lack of dyspnea in these patients can worsen the acceptance of a face mask, which is more uncomfortable than a tracheal cannula. In 2 children we waited with the definite closure of the tracheostomy due to pavor-like symptoms and laryngeal closure during sleep and problems in acceptance of the mask, respectively. In the other 2 children we could demonstrate effective non-invasive mask ventilation during temporary tracheal closure for several nights. Therefore the tracheostomy was definitely closed. Long-term follow-up with home monitoring showed effectiveness of non-invasive ventilation in these cases.

Respiratory changes associated with rapid eye movements in normo- and hypercapnia during sleep.

Rapid eye movements during rapid-eye-movement (REM) sleep are associated with rapid, shallow breathing. We wanted to know whether this effect persisted during increased respiratory drive by CO2. In eight healthy subjects, we recorded electroencephalographic, electrooculographic, and electromyographic signals, ventilation, and end-tidal PCO2 during the night. Inspiratory PCO2 was changed to increase end-tidal PCO2 by 3 and 6 Torr. During normocapnia, rapid eye movements were associated with a decrease in total breath time by -0.71 +/- 0.19 (SE) s (P < 0.05) because of shortened expiratory time (-0.52 +/- 0.08 s, P < 0.001) and with a reduced tidal volume (-89 +/- 27 ml, P < 0.05) because of decreased rib cage contribution (-75 +/- 18 ml, P < 0.05). Abdominal (-11 +/- 16 ml, P = 0.52) and minute ventilation (-0.09 +/- 0.21 ml/min, P = 0.66) did not change. In hypercapnia, however, rapid eye movements were associated with a further shortening of total breath time. Abdominal breathing was also inhibited (-79 +/- 23 ml, P < 0.05), leading to a stronger inhibition of tidal volume and minute ventilation (-1.84 +/- 0.54 l/min, P < 0.05). We conclude that REM-associated respiratory changes are even more pronounced during hypercapnia because of additional inhibition of abdominal breathing. This may contribute to the reduction of the hypercapnic ventilatory response during REM sleep.

[Control and development of breathing, pathophysiological aspects]. / Atmungsregulation und Entwicklung, pathophysiologische Aspekte.

The respiratory control system guarantees acid-base-homeostasis as well as the rhythmic activities of the respiratory motor system in accordance with exercise and behavioural programmes of the human being. Cortical patterns and synchronized respiratory patterns with tracheal flow and pressure variations in the fetus indicate the common network of respiration and sleep-wake mechanisms in an early stage already. During fetal life acid-base-homeostasis is dependent on progesterone controlled mechanisms. CO2 partial pressure of the uterine artery reduces to 32 mmHg. The O2 Partial pressure of the umbilical vein is 25-30 mmHg only. The raise of PCO2 during delivery is accompanied by a shower of sensory input to the reticular formation causing arousal and the opening of the lungs. The continuation of postnatal breathing is the consequence of the integration of the central chemosensitive mechanism and the reticular activating system at an adequate threshold. Perinatal defense reflexes, functional patterns and strategies in early life may outline later pathophysiological mechanisms for sleep apnea, apparently life threatening event (ALTE), sudden infant death, and congenital central hypoventilation syndrome.

[Postnatal development of breathing control]. / Postnatale Entwicklung der Atmungsregulation.

Respiratory movements already occur in the fetus together with low amplitude high frequency EEG. During birth external stimuli drive respiration, supported by the development of hypercapnia, hypoxia and acidosis. The thresholds of the chemosensitive systems adapt during the first hours and days of life (CO2 sensitivity) or weeks (hypoxic sensitivity). In 180 healthy infants between 5 days and 18 months of age we performed respiratory CO2-responses during NREM-sleep and studied the immediate response to inhalation of 60% oxygen (Dejours test) as well as in 8 children with congenital central alveolar hypoventilation syndrome (CCHS) and 15 infants who experienced an apparently life-threatening event (ALTE). Infants older than 2 weeks had a mean PCO2 of 40-42 mmHg, the slope of the CO2-response showed no age trend and was found in the range of adults with a 22-38% increase in ventilation per Torr increased PCO2. Preterm infants had a significant lower CO2-response (16 vs. 33%) until they reached their estimated normal birth date. In the ALTE group the CO2-response was suppressed to 17%. Children with CCHS did not respond to CO2 by increasing their ventilation, even after years. The response to hyperoxia as a measure of peripheral chemoreceptor activity decreased from a 31% initial inhibition of ventilation at 1 month to 20% at one year. Our results indicate that temporary or lasting reduction or lack of the respiratory CO2 sensitivity may cause apneic events or hypoventilation. Different slopes of CO2- and hyperoxic responses in very young infants compared to older ones favour the occurrence of oscillations in the control of breathing such as periodic breathing during sleep.

[Complications of nasal CPAP therapy. Consequences for general practice]. / Komplikationen bei der nasalen CPAP-Therapie. Konsequenzen für die Praxis.

BACKGROUND: The prevalence of the obstructive sleep apnea syndrome is about 5% in the entire population. The amount of treatment-indications grows for this particular sleep-related breathing disorder due to the increasing usage of diagnostic screening tests. In most cases, the positive-pressure ventilation, PPV (nCPAP, nBiPAP) is considered as a highly effective form of treatment, in comparison to other treating methods. The residential polysomnographic supervised adjustment of the treatment is optimally applied to most of the patients. Due to the increasing number of the treated patients, the reports about the appearance of short-termed side effects during the adjustment of the PPV become more frequent. PATIENTS AND RESULTS: We report on 9 patients who showed complications during the initial stage of treatment. The most common one, during the nCPAP-therapy, was the increase of central apneas. Because of this complication, a rapid optimization of the respiratory pressure or a change to a nBiPAP-therapy was necessary in 5 of the patients. 2 of the patients showed cardiac arrhythmias, some of which were severe. One patient produced a remarkable central hypoventilation during the initial phase of a nCPAP-therapy. The nBiPAP-titration combined with right-heart-catheter monitoring could demonstrate in another patient a possible cardiac decompensation through an increased ventilatory pressure. CONCLUSION: The risk of a positive-pressure ventilation is higher in patients with accompanying cardiac, pulmonary, neuropsychiatric and/or otorhinolaryngologic disorders. Considering the various predisposing factors of the patients we suggest an intensive apparative monitoring as well as stuff-supervision during the introduction to a respiratory treatment. If complications appear, a rapid improvement of the ventilatory pressure or a change to another respiratory treatment is indicated.

[Sleep and breathing disorders in patients with brain stem lesions]. / Störungen von Schlaf und Atmung bei Patienten mit Hirnstammläsionen.

Most information about the structures within the brain stem that modulate respiration and sleep are gathered from animal experiments. Therefore we examined 10 patients several weeks after an infarction of the brain stem by means of polysomnography and tested the chemosensitive drives of respiration. None of these patients complained about symptoms of sleep disordered breathing. In each case polysomnographic measurements and ventilatory response curves revealed pathologic findings. The respiratory response to CO2 was diminished or completely abolished in each patient. In some cases hypoventilation or disturbances of the respiratory rhythmicity could be seen. In several cases missing REM sleep, sleep fragmentation or the reduction of slow wave sleep were observed. The study indicates that on the base of results from animal research the comparison of morphological and pathophysiological data is helpful to gain a better understanding on the coupling of the respiratory system with sleep at the brain stem level as well as on the pathomechanism of sleep related breathing disorder.

[Continuous ambulatory monitoring in quality control of home therapy of congenital central hypoventilation syndrome (CCHS)]. / Kontinuierliche ambulante Uberwachung zur Qualitätskontrolle der Heimtherapie bei kongenitalem zentralem Hypoventilationssyndrom (CCHS).

4 children with congenital central hypoventilation syndrome (CCHS) now aged 6 to 9 years were studied for 1 to 8 years. In all patients CO2-response is missing, hypoxic drive is maintained. All patients required mechanical ventilation after birth. 1 patient is supported by controlled oxygen therapy during sleep since 9 months of age. 2 patients are IPPV-ventilated during sleep. 1 patient is pressure control ventilated with an oro-nasal mask since 6 years of age. All children showed phases of hypo- and hyperventilation (max. pCO2 107 mm Hg) depending on vigilance with respiratory acidosis in awake state and during sleep. These findings required ambulatory monitoring of home-therapy by a professional guard and continuous recording of pCO2 and pulseoximetry. These longtime data (max. pCO2 72 mm Hg) show that ambulatory monitoring and control of therapy is able to avoid extreme variation of blood gases and to stabilize acid-base regulation during sleeptime in patients with CCHS.

[Computer-assisted analysis of sleep stages using the laboratory software package "Spike 2"]. / Computergestützte Analyse der Schlafstadien mit Hilfe des Laborsoftwarepakets "Spike 2".

We used a laboratory software package for data capture and data analysis (Spike 2, CED) to develop a computerised sleep staging. The modular software is programmed to extract the following data: power spectral density in the alpha and delta frequency bands with fast Fourier Transformation, K-complexes using pattern recognition on the basis of signal amplitude and zero level crossings, sleep spindles using auto-correlation of the EEG signal, rapid eye movements with pattern recognition of the bipolar EOG signal using amplitude and time differences, and muscle tone from the rectified and integrated submental EMG signal. These results are displayed together with the raw signals of EEG, EOG, and chin EMG on a user-defined time scale. Thus visual scoring of sleep stages is easter. Furthermore a decision table, containing the sequence and weighting factors for the extracted parameters, serves to perform an automated sleep scoring.

Breathing, transcutaneous blood gases, and CO2 response in SIDS siblings and control infants during sleep.

Age-related changes of 20 variables describing breathing patterns, transcutaneous blood gases, and estimated CO2 response during sleep were examined in a cross-sectional study of 30 healthy control infants and 150 healthy siblings of sudden infant death syndrome victims within the first 18 mo of life. Whole-night measurements were performed using noninvasive respiratory induction plethysmography and transcutaneous blood gas electrodes. Each candidate for the study was extensively screened and found to be healthy. Mean transcutaneous PCO2 (PtcCO2, median 40.3 Torr) and maximum PtcCO2 (median 44.8 Torr), as well as the estimated ventilatory response to inhalation of 2% CO2 in air during regular breathing, causing a 20-36% increase of ventilation per Torr PtcCO2, were not related to postnatal age. In contrast, paradoxical breathing decreased from 49.5 to 0% of total sleep time (TST), periodic breathing from 5.5 to 0% TST, and respiratory rate during regular breathing from 40 to 22 breaths/min; the portion of regular breathing increased from 32 to 55% TST and mean and minimum transcutaneous PO2 from 65.4 and 47 to 69.7 and 52 Torr with increasing stability. The largest changes occurred in the first 6 mo of life. Maximum apnea duration (9.5 s, maximum 16 s), mean apnea duration (3.74 s, breathing pauses > or = 2 s), and time spent apneic per hour of irregular breathing (199 s/h) were not related to age. The comparison of data from siblings and controls showed similarities in the above-mentioned variables. No significant differences were found among the groups. Also a comparison of 30 pairs of siblings and controls, matched for age, gender, birth, and actual body weight, did not show significant differences. The present study extends the knowledge of development of breathing control beyond the first 6 mo of life.

Chemosensitive neurons on the ventral medullary surface.

Central chemosensitivity is ascribed to three areas on the ventral medullary surface. The discharge frequency of neurons observed in these areas depends upon pH. Other neurons within the same areas do not change their frequency during acidosis or alkalosis. Histologically the areas are characterized by superficial nerve cells.