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K H Rühle

Publications and source records attributed to K H Rühle.

At least 19 recordsLinked to original sources

[Spiroergometry in patients with severe chronic obstructive pulmonary disease confined to bed].

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.

Aged↗

Efficiency of cold passover and heated humidification under continuous positive airway pressure.

Cold passover and heated humidifiers are employed for the prevention of side-effects associated with continuous positive airway pressure (CPAP) treatment. However, to date, it has not been possible to separately measure the humidity of inspired and expired air. The aim of this study was to compare the relative humidity of the inspired air and the water loss during respiration between cold passover and heated humidifiers under CPAP. Humidity and temperature were determined separately for the respiratory phases, without humidification, with cold passover and heated humidifiers in 10 healthy subjects. Humidity was measured with a capacitive hygrometer, temperature with a "Type K" thermosensor, and impedance of the total respiratory system with impulse oscillometry. The relative humidity (rH) of the inspired air (mean+/-SD) increased significantly from 24.0+/-9.1%, rH (34.8+/-1.0 degrees C, no humidifier) to 34.5+/-10.1%, rH (34.6+/-1.0 degrees C) under cold humidification, and to 53.9+/-13.2% rH (35.0+/-1.1 degrees C) under heated humidification. With heated humidification, water loss was reduced by 38% compared to cold humidification. The impedance increased from 5.7+/-1.8 cmH2O x L x s(-1) (no humidifier) to 6.7+/-1.8 cmH2O x L x s(-1) (heated humidifier). The authors conclude that the use of a heated humidifier during continuous positive airway pressure appreciably increases the relative humidity of the inspired air and reduces the water loss during respiration.

Adolescent↗

[Evaluating oronasal flow with temperature (thermistor) and obstructive pressure (prongs)].

The measurement of oronasal flow during sleep studies using thermistors is internationally well accepted. As an alternative the possibility exists to measure the pressure at the nose by means of nasal prongs. Our objective was to compare and evaluate the methods to detect respiratory events in clinical routine, namely O2-saturation by pulse oxymetry oronasal flow by thermistors thoraco-abdominal effort by belts oronasal flow by prongs, 8 consecutive patients suspected of sleep apnoea syndrome (7 m, 1 f), mean age 56.5 +/- 9.5 years, height 173 +/- 6.4 cm, BMI 28.7 +/- 2.6 kg/m2, Epworth sleepiness scale score 9.1 +/- 3.2, AHI 24.9 +/- 13.7 h-1, lowest SaO2 86 +/- 4.9%, were examined. Between nose and mouth we fixed an oronasal 3-point thermistor and oronasal prongs (2 openings at the mouth and 2 openings at the mouth applying a common tube). During breathing the resulting pressure was registered with a pressure transducer parallel to the signal of the thermistors and the other polysomnographic data. We defined a respiratory event if at least one of the 4 signals met the criteria of a respiratory disturbance (for exact definitions see method). The detection rate of the 4 signals was calculated in relation to the sum of all events. Of the 1824 events (100%) only 52.3% were detected by an O2-desaturation of more than 4%, but 61.0% by thermistors. An acceptable detection rate was found measuring effort with 83.4%, only nasal prongs detected 95.1% of all events. We conclude that with regard to the detection rate of respiratory events the measurement of pressure by nasal prongs is superior to the use of thermistors.

Adult↗

[Comparison between anterior rhinomanometry and impulse-oscillometric rhinometry found within nasal allergen provocation].

UNLABELLED: Besides the standard method of anterior rhinomanometry (aR), the impulse-oscillometric rhinometry (IOS) is available for measurements of the nasal resistance. The aR is a procedure dependent on the cooperation of the patient, whereas IOS is measured regardless from the breathing activities of the patient. We examined weather the resistance-measurement by means of IOS in comparison to the aR is a more suitable method for nasal allergic provocation. METHOD: 17 patients with anamnestic known rhinokonjunktivitis (6 f, 11 m) had a pricktest and then a nasal provocation testing with an allergen which provoked a reaction on the skin. The complete resistance of the nose was measured in a randomized order by means of aR and IOS. RESULTS: The complete resistance showed neither in the basic measurement (aR 0,38 +/- 0,14 kPa/l/s; IOS 0,38 +/- 0,11 kPa/l/s) nor in the control solution (aR 0,38 +/- 0,14; IOS 0,39 +/- 0,14) nor after application of the allergenic solution (15 min: aR 0,69 +/- 0,27; IOS 0,77 +/- 0,42; 30 min: aR 0,65 +/- 0,29; IOS 0,6 +/- 0,38) a significant difference between the two methods. The results of the measurement of aR and IOS after the allergenic solution showed a positive correlation (15 min: r = 0,63, p < 0,01; 30 min: r = 0,67, p < 0,01). We found by means of clinic and measurement methods in the aR of 7 patients a positive reaction, within 7 patient a negative reaction, 3 patients had a unspecific nasal hyperreactivity. There was a correspondence in 6 of the 7 patients with positive reaction in aR between both methods. 4 of the 7 results with negative reaction in the aR would have been positive then underlying the same criteria in the IOS without announcing the symptomscore a relevant clinical symptomatic while testing. CONCLUSION: IOS is a suitable procedure for nasal provocation testing and provides results similar to the aR. In comparison to aR IOS is not dependent on the patients cooperation. Due to its higher sensitivity the valid limits of the aR at provocation testings cannot be transferred to IOS to avoid a false positive reaction.

Adult↗

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.

Cross-Over Studies↗

[Self-assessment by patients of impairment caused by obstructive sleep apnea syndrome].

BACKGROUND AND OBJECTIVE: The compliance of the nasal continuous positive airway pressure treatment (nCPAP) of the obstructive sleep apnea syndrome (OSAS) depends on the patients' awareness and improvement of the symptoms. Therefore, we studied the relevance of OSAS in different aspects of the quality of life and important aspects of daily life (driving performance, working place). METHODS: 352 patients with OSAS filled in a questionnaire of sociodemographic data and impairment of quality of life. The relevance of OSAS was evaluated with polysomnography and parameters of daytime sleepiness. RESULTS: The number of women was lower than expected from community related data. The apnea/hypopnea index was 29.9 +/- 23.4/h at baseline measurement and was reduced to 8.8 +/- 9.6/h with nCPAP (p < 0.001). The arousal index (baseline 26.6 +/- 15.3/h) fell with treatment significantly (17.7 +/- 9.2 Arousals/h, p < 0.001). The error rate in the driving simulator test was 7.8 +/- 8.9% (normal value 5.75 +/- 1.4). It was normalised with nCPAP (5.8 +/- 9.5, p < 0.001). 42.3% of patients reported about sleep apnea related symptoms for more than five years before diagnosis. The patients rated their physical fitness on a scale (0 to 6) at 2.9 +/- 1.3. It increased significantly with treatment to 3.4 +/- 1.3 an (p < 0.001). The mental activity improved significantly, too. The daytime sleepiness improved from 3.4 +/- 1.5 to 3.1 +/- 1.5 (p < 0.001). 32.3% of the patients reported that they fell asleep while steering at least once in the last month, 13.0% reported about more than five episodes/month. 5.3% of the patients thought their job in danger because of OSAS. 65.1% felt their performance in job to be impaired. CONCLUSION: OSAS impairs patients in different aspects of daily life, especially in the working place. The latency between the onset of symptoms and diagnosis is longer than expected. NCPAP treatment improves the symptoms of OSAS significantly both in criteria of polysomnography and self-assessment of the patients.

Activities of Daily Living↗

Detection of obstructive sleep apnea by analysis of phase angle using the forced oscillation signal.

Pharyngeal collapse in patients with obstructive sleep apnea syndrome (OSAS) is linked to decreased upper airway muscle activity. We hypothesised that decreased muscle activity causes decreased stiffness of the upper airway wall and assumed that a decrease in wall stiffness would result in a change point (CP) of the morphology of phase angle time series phi(t) obtained by forced oscillation technique (FOT). We developed an algorithm to detect CPs in &phi;(t) and investigated phi(t) data measured in parallel to all-night polysomnography in seven patients. A total of 2724 CPs were detected by algorithm. The CPs were marked on the polysomnograms and compared with polysomnogram scoring performed jointly by three sleep expert physicians. A total of 791 (67%) of the 1172 handscored respiratory events showed a CP in phi(t) within a time interval of 8 sec before and 6 sec after the marked onset. A total of 672 (57%) respiratory events were detected at an earlier time by algorithm, and 119 (10%) were algorithmically detected later. The average detection time by the CP algorithm was 4.0+/-1.1 sec earlier than the manual scoring. We conjecture that a CP in phi(t) indicates a change in upper airway collapsibility and that phi(t) might be a potentially useful parameter for detection of impending upper airway obstruction.

Adult↗

[The driving simulation test "carsim" for assessing vigilance. Effect of driving practice and other factors in health subjects and in patients with sleep apnea syndrome].

Among other factors, obstructive sleep apnoea (OSAS) patients suffer from impaired continuous attention. For registration and objectification as well as observation of the course of therapy, driving simulation programmes are particularly suitable. "Carsim", a driving simulation newly developed by us, simulates a bendy road via a screen where a vehicle is supposed to be kept on the right lane by operating a steering wheel. Apart from examination of quality criteria (objectivity, reliability, validity) and establishment of standard values, the influence of significant variables (age, gender, school education, profession, duration of disorder, AHI, BMI, visual and motor functionability, driving license, driving experience, Epworth score, accident frequency) on patients and healthy controls requires to be evaluated. For this purpose, 100 healthy controls, 200 OSAS patients and 30 patients under nCPAP were analysed. In healthy persons and patients under nCPAP, driving experience had no impact on the driving simulation results. OSAS patients with no driving license and no driving experience achieved lower marks for tracking than patients with driving license or a lot of driving experience (no driving license: x = 8058 +/- 10,878 track deviations; with driving licence: x = 2111 +/- 6564 track deviations; p < .001). According to our findings, untreated OSAS severely interferes with patients' attention capacity as well as their coping strategies.

Arousal↗

[Measurement of mask leakage during CPAP in patients with obstructive sleep apnea].

UNLABELLED: To improve the compliance of patients with obstructive sleep apnoea tight fitting nasal masks are necessary. It would be very useful to to measure the mask leakage during the recommended pressure for the treatment at home. We studied therefore the influence of different sizes and types of masks on the air leaks during the adaptation procedure. We investigated 20 patients, mean age 60.8 +/- 11.9 years, AHI 31 +/- 17, lowest oxygen saturation 81 +/- 10.3% mean CPAP-9.9 +/- 1.6. Randomized cross over we applied CPAP with different masks during wakefulness. The pressure was increased from 6 to 13 mbar by steps of 1 mbar. The mask leak was measured by Autoset. RESULTS: Using the best mask (selected from different sizes and different brands) the mask leak was 0.11 +/- 0.9 L/sec. If the patient used a mask (only one brand but selected from different sizes) or one standard mask the mask leak doubled respectively tripled. To reduce side effects and improve compliance we recommend therefore quantification of the mask leak to find the best fitting mask.

Equipment Failure↗

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.

Adult↗

Detection of sleep apnea with the forced oscillation technique compared to three standard polysomnographic signals.

BACKGROUND: The forced oscillation technique (FOT) allows analysis of the upper airway impedance and, hence, detection of obstructive sleep apnea. OBJECTIVE: To evaluate FOT with respect to sensitivity and to specificity in online detection of sleep-disordered breathing patterns and to compare algorithmic onset detection time with manual onset time markers of staff physicians. METHODS: We compared the absolute value mid R:Zmid R: of the impedance with three routinely obtained polysomnographic signals - nasal airflow V(nasal), thoracic excursion Thox and esophageal pressure P(es) - by retrospective analysis of the diagnostic polysomnograms of 51 patients. For each signal we evaluated algorithms for online detection of respiratory events. For each out of five apnea classes, 50 respiratory events marked by staff physicians were drawn randomly from the 51 polysomnograms to optimize the online detection algorithms (learning set). The algorithm analyzes relative changes of signal baseline and amplitude. Again 50 respiratory events were drawn randomly for each apnea class to examine to what extent it is possible to detect event onsets with the algorithms (test set). RESULTS: The sensitivity of the signals varied between 56 and 94% and was on average 74%. The specificity was 96 +/- 1.5% on average. The onset was detected 4-6 s after the initially evaluated onset of the staff physicians. CONCLUSION: We conclude that nasal airflow and FOT are equivalent sensitive measurands for detection of respiratory events.

Adult↗

A test for the determination of sustained attention in patients with obstructive sleep apnea syndrome.

BACKGROUND AND OBJECTIVES: To investigate the parameter daytime sleepiness in patients with the sleep apnea syndrome (SAS), a test for measurement of sustained attention was developed. The present studies were performed on volunteers undergoing preemployment medical examinations and SAS patients to determine the extent to which test results are in agreement with the symptoms of SAS and traffic accident reports, and also with daytime sleepiness, and whether learning or therapeutic effects can be seen with repeated tests prior to and following treatment with nasal continuous positive airway pressure (nCPAP). METHODS PARTICIPANTS: 125 healthy volunteers, and two groups of 28 SAS patients each. DESIGN: Study A: The volunteers underwent a single attention test and completed a questionnaire concerned with traffic accidents and symptoms of sleep-related breathing disorders. Study B: SAS patients underwent two attention tests before treatment. Study C: SAS patients underwent one attention test before and one after nCPAP therapy. RESULTS: Study A: The error rate in volunteers without symptoms of sleep-related breathing disorders (51 persons) was 4.7 +/- 4.3% (number of errors 14.1 +/- 12.9), 95% CI: 1.2 (number of errors 3.6). No dependence of the error rate on age, BMI or sex was found. In persons with a history of apneic events (n = 10), the error rate was 10.6 +/- 10.0% (number of errors 31.8 +/- 30), in those with more than two accidents during the last 5 years (n = 4), it was increased to 15.3 +/- 9.7% (number of errors 45.9 +/- 29.1). Study B: Among SAS patients, no significant learning effect was seen, and prolongation of the test duration beyond 30 min had no effect on the test results. Study C: The error rate improved significantly with nCPAP [10.6 +/- 13.5 vs. 6.4 +/- 8.9% (number of errors 31.8 +/- 40. 5 vs. 19.2 +/- 26.7), p < 0.001]. CONCLUSIONS: The attention test can be helpful for the measurement of daytime sleepiness, and CPAP therapy can improve test performance.

Accidents, Traffic↗

[Obstructive sleep apnea syndrome caused by occupational exposure to solvents].

HISTORY AND ADMISSION FINDINGS: A 52-year-old man working in a chemical laboratory was referred with the possible diagnosis of toxic encephalopathy. For 17 years he had been exposed to high concentrations of perchlorethylene and n-butanol vapours which every day had caused acute symptoms of organic solvent intoxication. Current complaints were autonomic nervous system symptoms, loss of concentration and memory, and fatigue in the second half of the day. The patient was obese but in good general condition. INVESTIGATIONS: Neuropsychiatric examination confirmed the reported loss of concentration and planning ability at work. The polysomnogram indicated an increased number of largely obstructive apnoea attacks. DIAGNOSIS, TREATMENT AND COURSE: As the patients had an obstructive type of sleep apnoea treatment consisted of positive pressure ventilation at night and weight reduction. The occupational exposure to organic solvents was the likely cause. CONCLUSIONS: As the symptoms of encephalopathy and sleep apnoea syndrome overlap, the latter should be considered before an encephalopathy is diagnosed. Because a rare cause of the sleep apnoea syndrome is prolonged and marked occupational exposure to organic solvents this should be asked about in taking the history. If indeed there has been occupational exposure, it should cease at once and be reported.

1-Butanol↗

[Optimising CPAP accommodation time by feedback-supported training phases in patients with obstructive sleep apnea syndrome].

Mask fitting and accommodation of CPAP-devices are of great importance. Only by accommodation over several hours, problems concerning mask size and fixation of mask are recognised and solved. Many patients overestimate the time they needed for achieving accommodation. We therefore asked whether by visualizing the time required for accommodation the accommodation time can be prolonged. Additionally we compared the subjective estimation on the time with the objectively measured time. We studied 20 patients with sleep apnoea syndrome, 13 men and 7 women, age 53 +/- 4 years, apnoea/hypopnoea index 32 +/- 16, lowest O2 saturation 83 +/- 6%. In a randomized cross-over study, a clock with a large 7 segment-display was either not visible in one setting, so that the patient had no control of the training-time, or the time was visible on the display. Thus the patient could possibly be motivated to increase his time of CPAP-accommodation during the day. The pressure-controlled clock counted only the time during which the pressure was above 4 HPa. In the setting with visible time-counter the accommodation time was 265.8 +/- 114 min, if the counter was not visible, time was only 210.8 +/- 91 min. If the patient cannot observe the time-counter he over-estimates the objectively measured time by half an hour (247.2 +/- 97.5 estimated vs. 210.8 +/- 91.0 actually). Thus the self-control of CPAP-accommodation by a visible clock leads to a significant prolongation of the exercise time. The estimation by the patient is only a limited means to evaluate the time of CPAP accommodation during the day.

Biofeedback, Psychology↗

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.

Adult↗