[Variability of the treatment pressure under continuous positive airway pressure treatment in obstructive sleep apnea syndrome]. / Quantifizierung der Druckvariabilität unter kontinuierlicher Positivdruckatmung bei obstruktivem Schlafapnoesyndrom.

BACKGROUND: Selfadjusting CPAP therapy is mostly employed if constant CPAP does not sufficiently suppress respiratory disturbances or is not accepted by the patient. The number of respiratory disturbances and thus the pressure need varies with sleep stages and body position during sleep. However, the analysis of the pressure profile during automatic CPAP therapy indicates a relevant variability of treatment pressure which is independent of the above mentioned criteria. Therefore, we aimed to quantify the pressure variability and its significance in patients with obstructive sleep apnea syndrome (OSAS). METHODS: We analysed the pressure profile during a six-week treatment period with selfadjusting CPAP therapy based on the measurement of the impedance (APAP FOT ). The variability index (VI) was calculated from the deviations of the treatment pressure from the mean pressure. The variability was considered to be low and clinically irrelevant if the VI did not exceed 0.75 as a mean value and in more than 10 % of the nights. PATIENTS: 20 patients (male 19, age 55.5 +/- 10.9 years, BMI 36.6 +/- 26.5 kg/m (2), AHI 36.9 +/- 21.3/h) who were treated with APAP FOT because of intolerance or inefficiency of constant CPAP. RESULTS: The VI was 0.9 +/- 0.7 (range 0.27 +/- 0.05 to 1.95 +/- 0.83). The number of nights with a figure >/= 0.75 reached 17.6 +/- 13.8 (range 0 - 40). In 50 % of the patients the mean VI was lower than 0.75. However, in 7 of these 10 patients the VI exceeded 0.75 in more than 10 % of the nights (4 - 15). Only 3 of 20 patients fulfilled both criteria of pressure stability. The VI showed a significant correlation with P mean (r: 0.66, p < 0.001). CONCLUSIONS: In most patients with difficult-to-treat OSAS a variability of the treatment pressure can be found.

[Importance of routine examinations in patients with obstructive sleep apnea syndrome]. / Bedeutung internistischer Routineuntersuchungen bei Patienten mit obstruktivem Schlafapnoe-Syndrom.

BACKGROUND AND OBJECTIVE: In patients with obstructive sleep apnea syndrome (OSAS) there is an increased comorbidity of internal diseases such as hypertension, coronary heart disease, chronic obstructive pulmonary disease and endocrine diseases. We analyzed prospectively frequency and consequences of pathological results in routine examinations of internal medicine in sleep laboratory. METHODS: 250 patients with OSAS underwent routine bodyplethysmography, blood- gas analysis, electrocardiogram and laboratory studies after anamnesis and clinical examination. Prior to this we indicated, whether we based on history and physical examination deemed any of these examinations necessary. Frequency and kind of pathological results as well as the consequences were analyzed. RESULTS: 129 results of bodyplethysmography and blood-gas analysis were pathological (51.6 % of all investigations), most frequently hypoxemia (22 %) and obstructive pattern (16.4 %). Further steps were necessary in 19 patients (7.6 %); the indication was seen before in 13 patients, therefore 6 results with consequences (2.4 %) were not expected. Laboratory studies were abnormal in 133 patients (53.2 % of all investigations), most of them hyperglycaemia (26.8 %) and elevated liver enzymes (20.4 %). 29 results (11.6 %) had consequences, of which 16 (6.4 %) were not expected. 82 electrocardiograms were pathological (32.8 % of all investigations), presenting most frequently as coronary heart disease (21.2 %). Further steps were necessary in 5 patients (2 %), while that was not expected in 3 patients (1.2 %). CONCLUSIONS: Routine examinations of internal medicine in patients with OSAS frequently present pathological results, which seldom have further consequences. As most of the important results can be predicted by history and clinical investigation, pathological by chance diagnoses are rare. With the exception of blood sugar tests routine examinations for patients with OSAS should be considered critically.

[Spiroergometry in patients with severe chronic obstructive pulmonary disease confined to bed]. / Spiroergometrie bei bettlägerigen Patienten mit schwergradiger COB.

BACKGROUND: Exercise training is recommended for patients with severe chronic obstructive pulmonary disease (COPD) to improve the endurance capacity. While many patients confined to bed are not able to run exercise training, we investigated the influence of a bedside passive-ergometry on ventilation in patients with severe COPD. METHODS: In nine patients with severe COPD confined to bed (FEV1.0 0,94 +/- 0,18 l, IVC 2,3 +/- 0,8 l, Raw 0,91 +/- 0,13 kPa/l/s) we measured oxygen uptake O2, breathing frequency BF and minute ventilation E during rest, passive movement (30 revolutions per minute), additional active movement and maximal exercise. As a control group six healthy men were investigated during rest and passive movement. RESULTS: During maximal exercise in COPD patients O2 peak reached 618 +/- 177 ml/min, BF 26 +/- 7,2/min and E max 24,1 +/- 5 l/min. In rest O2 was 311 +/- 56 ml/min (53 % O2 peak), BF 17,6 +/- 3,1/min and E 13,3 +/- 2,7 ml/min (55 % E max), while during passive movement O2 was increased to 369 +/- 88 (62 % O2 peak), BF to 19 +/- 5,3 and E to 16,4 +/- 4,1 (68 % E max). In contrast O2 in control subjects dropped from 377,5 +/- 38 in rest to 336 +/- 27 ml/min during passive action, BF from 14 +/- 2,1 to 12 +/- 2,4/min and E from 11,1 +/- 1,3 to 9,1 +/- 1 ml/min. CONCLUSIONS: In patients with severe COPD oxygen uptake, breathing frequency and minute ventilation increased not only during active, but even during passive movement of a bedside ergometer. With this method an exercise training is possible even in COPD patients confined to bed.

Autoadjusting CPAP therapy based on impedance efficacy, compliance and acceptance.

Constant continuous positive airway pressure (CPAP) is the treatment of choice for the obstructive sleep apnea syndrome (OSAS). To enable the pressure to be matched more accurately to actual requirements, and thus increase patient acceptance, an autoadjusting device based on the measurement of upper airway impedance was developed (APAP(FOT)). We investigated the efficacy and compliance in continuous use at home. Fifty-two patients were treated (randomized crossover) with CPAP and APAP(FOT) for 6 wk each. Respiratory disturbances, sleep profile, and arousals improved significantly with both modes (AHI: baseline, 35.1 +/- 26/h; APAP(FOT), 5.0 +/- 5.2; CPAP, 4.3 +/- 6.3; p < 0.001 baseline versus each mode). The mean pressure with APAP(FOT) was significantly reduced as compared with CPAP (CPAP, 7.8 +/- 1.5 cm H2O; APAP(FOT), 5.7 +/- 1.8 cm H2O; p < 0.001). Under APAP(FOT) the pressure was lower than that under CPAP for 81.5 +/- 21% of the time. Although overall use did not differ, 75% of the patients preferred APAP(FOT) for home treatment. We conclude that APAP(FOT) is as efficacious as constant CPAP in the treatment of OSAS. The treatment pressure can be reduced significantly, and sleep microstructure improved with APAP(FOT). These might be the reasons for patient preference of automatic therapy.

Self-adjusting continuous positive airway pressure therapy based on the measurement of impedance. A comparison of free pressure variation and individually fixed higher minimum pressure.

BACKGROUND: Measurement of impedance using forced oscillation technique is a sensitive means of detecting airway obstructions, including the obstructive sleep apnea syndrome (OSAS). OBJECTIVE: The present study was conducted to determine whether treatment with an automated impedance-controlled continuous positive airway pressure (CPAP) device (APAP(FOT)) is possible in patients with OSAS, and which is the best range of pressure variation in automatical CPAP treatment. We investigated two modes of APAP(FOT) with different pressure ranges: (1) the widest technically possible pressure range and (2) a range with individually defined minimum pressure. METHODS: Ten patients [9 men, age 56.6+/-10.5 years, BMI 32.0+/-4.5 kg/m(2), apnea/hypopnea index (AHI) 18.2+/-13.3 /h] had a diagnostic polysomnography (baseline). After manual titration of positive airway pressure they were submitted, in randomized order, to two modes of the APAP(FOT) device, namely pressure range of 4.0- 15.5 mbar (mode 1 free range) and an individually fixed higher minimum pressure with a maximum pressure of 15.5 mbar (mode 2). RESULTS: While the manually titrated pressure was 8.0+/-1.3 mbar, in mode 1 it was 5.6+/-2.1 mbar (p<0.01); in mode 2 7.3+/-1.6 mbar (p< 0.05). Both of these modes suppressed abnormal respiratory events (baseline AHI 18.2+/-13.3/h; mode 1: 2.5+/-1.9; mode 2: 1.8 +/-0.7, p<0.01 in each case), and increased slow wave sleep (baseline: 10.6+/-8.0%, mode 1: 20.2+/-10.4%, p<0.05; mode 2: 22.3+/-9.3%, p<0.01). In mode 1, the pressure was lower than that titrated manually in 73.2% of total sleep time, in mode 2 in 48.6%, while pressures higher than those derived manually were observed in 13.0% in mode 1 and in 19.1% in mode 2. CONCLUSIONS: The data indicate that impedance-controlled CPAP (APAP(FOT)) allows adequate treatment of OSAS patients at significantly lower pressures as compared with manually titrated pressure. Differences between the two modes are only minor.

[Time course of ventilatory drive in patients with kyphoscoliosis before and during intermittent ventilation]. / Verlaufsbeobachtung des Atemantriebs bei Patienten mit Kyphoskoliose vor und unter intermittierender Selbstbeatmung.

The aim of this retrospective study was to investigate the mouth-occlusion-pressure under CO2-stimulation in five patients (3 women, 2 men) suffering from kyphoscoliosis of different aetiology whilst being under noninvasive ventilation for respiratory muscle fatigue. Ten months after initiation of noninvasive ventilation we could demonstrate a marginal improvement of respiratory muscle strength but the P0.1 CO2-decreased slightly. We conclude that this decrease might be due to an increase in tidal volume allowing for a reduction in respiratory rate.

Self-adjusting nasal continuous positive airway pressure therapy based on measurement of impedance: A comparison of two different maximum pressure levels.

STUDY OBJECTIVE: Automatic titration using the forced oscillation technique (FOT) has recently been developed for the treatment of obstructive sleep apnea syndrome (OSAS). So far, it is not known if therapy with automatic nasal continuous positive airway pressure (nCPAP) using a preset upper pressure limitation or a free range (which might lead to higher mean pressure) is preferable with regard to obstructive events, sleep stages, and pressure characteristics. DESIGN: After diagnostic polysomnography, patients were randomly assigned to two settings with the self-adjusting nCPAP (APAP) device based on the FOT. In mode 1, the pressure variation ranged from 4 to 15.5 cm H(2)O, and in mode 2, the pressure variation ranged from 4 cm H(2)O to an individual upper pressure limit. PATIENTS: Eleven men, aged 53.0 +/- 6.8 years with a body mass index of 32.4 +/- 5.1 kg/m(2) and an apnea-hypopnea index (AHI) of 31.6 +/- 26.6/h. MEASUREMENTS AND RESULTS: Manually titrated pressure was at 9.3 +/- 2.1 cm H(2)O, the mean pressure in mode 1 was 5.4 +/- 1.0 cm H(2)O (p < 0.01), and the mean pressure in mode 2 was 5.1 +/- 0.7 cm H(2)O (p < 0.01). A reduction of respiratory events (baseline AHI, 31.6 +/- 26.6/h; AHI in mode 1, 3.4 +/- 4.5; AHI in mode 2, 5.0 +/- 7.2; each with p < 0.001) and an increase in the "rapid eye movement" stage of sleep (baseline, 13.0 +/- 5.5%; mode 1, 22.0 +/- 7.7 [p < 0. 05]; mode 2, 23.0 +/- 7.9 [p < 0.01]) were achieved. In mode 1, the mean pressure was below the manual pressure 91.7 +/- 9.3% of the time, and in mode 2, the mean pressure was below the manual pressure 90.4 +/- 6.3% of the time. The manual pressure was exceeded by 5.5 +/- 7.4% (mode 1) and by 5.2 +/- 3.1% (mode 2). CONCLUSION: We conclude that nCPAP therapy based on the FOT permits the adequate treatment of OSAS with significantly lower pressure than manually titrated nCPAP therapy does. A presetting of an upper pressure limit has no advantage compared to free range.

[Effect of noninvasive ventilation on pulmonary artery pressure in patients with severe kyphoscoliosis]. / Der Effekt der nichtinvasiven Beatmung auf den pulmonalarteriellen Druck bei Patienten mit schwerer Kyphoskoliose.

BACKGROUND: Many studies have shown, that non invasive ventilation via nasal access can normalize alveolar ventilation for individuals due to kyphoscoliotic deformity. The purpose of this study was to evaluate the effect of nasal IPPV on the pulmonary artery pressures (Pam) and the sleep efficiency of kyphoscoliotic individuals. PATIENTS AND METHODS: Five patients were studied (4 men, 1 woman; age 50.5 +/- 6.9 years): all patients showed hypoxemia and hypercapnia before therapy. We followed the patients about 6 months under NIPPV. We measured PImax, PaO2, PaCO2, Pam before and after 6 months with NIPPV. RESULTS: PImax increased from 4.9 +/- 2.3 kPa to 6.5 +/- 1.3 kPa, PaO2 increased from 46.2 +/- 12.2 mmHg to 56.7 +/- 8.5 mmHg. PaCO2 decreased from 53.0 +/- 3.2 to 45.3 +/- 3.2. Pam decreased from 41.0 +/- 15.1 to 23.2 +/- 10.7 in 6 months of NIPPV. Total sleep time increased from 222 +/- 52 min to 326 +/- 43 min with NIPPV. CONCLUSION: Similar to O2 long-term therapy in patients with COPD. NIPPV delivers in patients with kyphoscoliotic deformity a significant reduction of pulmonary artery pressure and increase of sleep quality.