Interrater reliability between scorers from eight European sleep laboratories in subjects with different sleep disorders

Interrater variability of sleep stage scorings is a well-known phenomenon. The SIESTA project offered the opportunity to analyse interrater reliability (IRR) between experienced scorers from eight European sleep laboratories within a large sample of patients with different (sleep) disorders: depression, general anxiety disorder with and without non-organic insomnia, Parkinson's disease, period limb movements in sleep and sleep apnoea. The results were based on 196 recordings from 98 patients (73 males: 52.3 +/- 12.1 years and 25 females: 49.5 +/- 11.9 years) for which two independent expert scorings from two different laboratories were available. Cohen's kappa was used to evaluate the IRR on the basis of epochs and intraclass correlation was used to analyse the agreement on quantitative sleep parameters. The overall level of agreement when five different stages were distinguished was kappa = 0.6816 (76.8%), which in terms of kappa reflects a 'substantial' agreement (Landis and Koch, 1977). For different groups of patients kappa values varied from 0.6138 (Parkinson's disease) to 0.8176 (generalized anxiety disorder). With regard to (sleep) stages, the IRR was highest for rapid eye movement (REM), followed by Wake, slow-wave sleep (SWS), non-rapid eye movement 2 (NREM2) and NREM1. The results of regression analysis showed that age and sex only had a statistically significant effect on kappa when the (sleep) stages are considered separately. For NREM2 and SWS a statistically significant decrease of IRR with age has been observed and the IRR for SWS was lower for males than for females. These variations of IRR most probably reflect changes of the sleep electroencephalography (EEG) with age and gender.

Application of ion-sensitive sensors in water quality monitoring

Within the last years a trend towards in-situ monitoring can be observed, i.e. most new sensors for water quality monitoring are designed for direct installation in the medium, compact in size and use measurement principles which minimise maintenance demand. Ion-sensitive sensors (Ion-Sensitive-Electrode--ISE) are based on a well known measurement principle and recently some manufacturers have released probe types which are specially adapted for application in water quality monitoring. The function principle of ISE-sensors, their advantages, limitations and the different methods for sensor calibration are described. Experiences with ISE-sensors from applications in sewer networks, at different sampling points within wastewater treatment plants and for surface water monitoring are reported. An estimation of investment and operation costs in comparison to other sensor types is given.

In-line river monitoring--new challenges and opportunities

Water management becomes a complex issue when considering the large number of water-rights-of-use like drinking water production, recreation, receiving water, transport on and ecological quality of the water bodies. Recent changes in the legal requirements concerning water management on European scale (EC Water Framework Directive, 2000/60/EC) highlighted the need for appropriate means for monitoring water quality and exchange of water quality data. Indirect measurement of water quality using surrogate parameters (chemical and physical-chemical parameters) can be automated at a high accuracy level. This was shown over the past years by national and international research projects. In 2001 such a research project has started in Austria focusing on the installation and operation of a pilot water quality network, which is suitable for application at several points of interest of water management, i.e. sewer networks, wastewater treatment plants and receiving water bodies. The paper describes the operational problems and experiences of collecting data over a period of one year in the Danube River downstream of Vienna. The sensors are installed in situ, directly in the river, without any bypass system. The first evaluation of the measurements shows that the values are reliable and therefore applicable to further interpretations.

Quantification of pollution loads from CSOs into surface water bodies by means of online techniques

Based on novel technologies, a modular online monitoring station suitable for continuous application in sewer networks, wastewater treatment plants and receiving water bodies has been designed. The monitoring station serves as the backbone of a water quality pilot network. As one part of this network a sewer monitoring station has been installed at a combined sewer overflow in Graz to quantify pollution concentrations and loads in the combined sewer and into the receiving water and is operated since October 2002. The design and equipment of the measurement station and first operating experiences and results are given in this paper.

Insomnia related to postmenopausal syndrome and hormone replacement therapy: sleep laboratory studies on baseline differences between patients and controls and double-blind, placebo-controlled investigations on the effects of a novel estrogen-progestogen combination (Climodien, Lafamme) versus estrogen alone

Differences in sleep and awakening quality between 51 insomniac postmenopausal syndrome patients and normal controls were evaluated. In a subsequent double-blind, placebo-controlled, comparative, randomized, three-arm trial (Climodien 2/3 = estradiol valerate 2 mg + the progestogen dienogest 3 mg = regimen A, estradiol valerate 2 mg = regimen EV, and placebo = regimen P), the effects of 2 months of hormone replacement therapy were investigated, followed by a 2-month open-label phase in which all patients received Climodien 2/2 (EV 2 mg + dienogest 2 mg = regimen A*). Polysomnography at baseline demonstrated significantly deteriorated sleep initiation and maintenance, increased S1 and decreased S2 in patients. Subjective sleep and awakening quality, well-being, morning drive, wakefulness, memory and reaction time performance were deteriorated too. Treatment with both regimen A and regimen EV induced a moderate, although nonsignificant, improvement in the primary efficacy variable wakefulness during the total sleep period compared with baseline, while under placebo no changes occurred. Secondary efficacy variables concerning sleep initiation and maintenance, and sleep architecture showed similar findings. The apnea and apnea-hypopnea indices improved significantly under regimen A, compared with both baseline and placebo. Subjective sleep and awakening quality improved significantly after regimen A and EV compared with baseline, with the drug-induced changes being superior to those induced by placebo. In the open-label phase, subjective sleep quality improved further, significantly in the former regimen A group. Awakening quality, somatic complaints and morning thymopsyche did not yield any significant findings. Concerning morning noopsychic performance, memory improved significantly after regimen A compared with baseline, fine motor activity after regimen EV. Reaction time performance increased with all three compounds. In conclusion, Climodien significantly improved subjective sleep quality, the apnea and apnea-hypopnea indices of insomniac postmenopausal syndrome patients, while it only marginally improved variables concerning objective sleep and awakening quality.

Quality of life in nonorganic and organic sleep disorders: II. Correlation with objective and subjective quality of sleep and awakening

OBJECTIVE

The purpose of this study of 100 patients suffering from sleep-disorders was to determine correlations between their subjective health-related quality of life (HRQoL) and objective variables in sleep initiation and maintenance, sleep architecture, objective quality of awakening, psychophysiological parameters and subjective quality of sleep and awakening.

METHODS

Objective measurements were obtained from overnight diagnostic polysomnography. Subjective HRQoL was determined from the Quality of Life Index (QLI, Mezzich and Cohen) completed prior to the adaptation night. Other measurements included subjective and objective quality of sleep and awakening (psychometry) the evening before and morning after polysomnographic investigations.

RESULTS

63% of the patients were suffering from nonorganic and 37% from organic sleep disorders (SDs). Within the first group, nonorganic insomnia predominated; within the second, sleep apnea. Subjective HRQoL correlated well with subjective sleep and awakening quality, especially in nonorganic SDs. There were only a few correlations of objective measurements with subjective HRQoL: in the total group of SD patients HRQoL correlated with sleep stage S2, and in nonorganic SDs with attention scores and psychophysiological measurements (mainly the pulse rate in the evening and morning).

CONCLUSION

Our findings suggest only a weak relationship between objective sleep variables and subjective HRQoL in both organic and nonorganic SDs. However, we found various significant correlations of HRQoL with subjective measurements of sleep, especially in nonorganic SDs.

Scalp topography of the spontaneous K-complex and of delta-waves in human sleep

OBJECTIVE

Together with spindles, K-complexes are well known hallmarks of stage 2 sleep (S2). However, little is known about their topographical distribution in comparison to delta-waves and to K-complexes superimposed by spindles.

PATIENTS AND METHODS

In this study, the topographical distribution of spontaneous K-complexes and delta-waves in S2 and delta-waves in stage 4 sleep (S4) in 10 healthy young adults (aged 20 to 35 years, 7 female) was investigated. K-complexes with and without spindles in S2, delta-waves with and without spindles in S2, and delta-waves in S4 distributed all over the night were visually selected. EEG power maps and statistical parametric maps were calculated.

RESULTS

Absolute delta power of S2 K-complexes appeared to be significantly higher than of S2 delta-waves and delta power of S4 delta-waves was higher than of S2 delta-waves. In K-complexes and delta-waves, power was found to be highest over medio-frontal regions in the delta frequency band (0.5-4.0 Hz) with a second maximum occipitally in delta-waves, no matter whether superimposed by a spindle or not.

CONCLUSION

K-complexes and delta-waves in S2 differ in topographical distribution. Even though in S2 delta-waves have less power, they have a similar topographical distribution in S2 and S4, supporting the hypothesis that delta-waves in S2 further develop towards delta-waves in slow wave sleep. The delta frequency components of K-complexes and delta-waves are unaffected by spindles.

[Objective assessment and therapeutic efficacy of an improved mandibular advancement device for snoring and sleep apnea syndromes with polysomnography]

In the treatment of snoring (SN) and sleep-related breathing disorders (SRBD), mandibular advancement devices (MAD) are of increasing importance. Their mode of action is based on the advancement of the mandible, thereby increasing various upper airway dimensions and thus airway patency and airflow during sleep. The aim of the present study was to investigate efficacy and tolerability of an individually fitted MAD on 11 patients (10 males, 1 female), mean age 57 years, using sleep laboratory methods in 3 subsequent nights (adaptation-, baseline-, treatment night). The MAD consists of 2 separate parts that attach to both dental arches. On occlusion the upper maxillary part with a protruding cone meets an inclined plane of the lower mandibulary part, thereby forcing the mandible to advance. 10 patients (6 with obstructive sleep apnea, 3 with obstructive hypopnea and 1 primary snorer) tolerated the MAD well; one patient (primary snorer) removed the MAD after 1 hour. Regarding the target variable, the snoring index (SI), confirmatory statistics demonstrated a significant improvement from 108 to 53/h sleep, though normalisation could not be achieved. Descriptive data analysis showed significant improvement of the apnea-hypopnea index (AHI) from 15 to 5.5/h and of the oxygen desaturation index (O2-DI) from 21 to 13/h sleep. Arousal variables and periodic leg movement index (PLMI) improved as well. Objective sleep efficiency and subjective sleep- and awakening quality remained unchanged. Thus, besides the good therapeutic efficacy (the medians of improvement of the SI, AI, AHI, O2-DI and PLMI were 37, 48, 53, 51 and 29%, respectively), acute acceptance of the MAD was also satisfactory. Last but not least our present study showed once more the necessity of an adaptation night, as from the first to the second sleep laboratory night respiratory indices deteriorated significantly.

Neopterin as a marker of immunostimulation: an investigation in anaesthetic workplaces

Personnel working in operating theatres and recovery rooms are exposed to a variety of noxious substances. The results of studies of the effects of occupational exposure on immune parameters are conflicting. Neopterin is an acknowledged marker of immunostimulation. Urinary neopterin levels of 58 anaesthetists and anaesthetic nurses were measured over a 3-week period. Neopterin analyses were performed using high performance liquid chromatography. Neopterin levels were within the normal range for all subjects. Younger subjects (aged < or = 35 years) had significantly higher urinary neopterin concentrations than older subjects (aged > 35 years). The present study is the first to investigate the influence of anaesthetic exposure on neopterin levels. No evidence of immunostimulation was found.

Monitoring pollution by proton-transfer-reaction mass spectrometry during paediatric anaesthesia with positive pressure ventilation via the laryngeal mask airway or uncuffed tracheal tube

Twenty children aged 2-66 months were randomly allocated for airway management with either the laryngeal mask airway or uncuffed tracheal tube using intermittent positive pressure ventilation with a tidal volume of 8 ml.kg-1 and a respiratory rate adjusted to maintain end-expiratory carbon dioxide concentration at 5.3 kPa. Induction was with fentanyl/propofol and maintenance was with sevoflurane 2.5% in oxygen/air. The airway device was removed when the patients were awake and the patients were transferred to the postanaesthesia care unit 10 min later. Air was sampled from a point 1.5 m above the floor at a location remote from the ventilation outlet and analysed using a proton-transfer-reaction mass spectrometer capable of continuous trace gas analysis at the parts per billion volume (ppbv) level. The concentration of sevoflurane was recorded every minute during three consecutive phases: for 5 min before the introduction of sevoflurane (background); after introduction of sevoflurane until removal of the airway device (intra-operative); and every minute after removal until the concentration returned to background levels. Median (interquartile range [range]) intra-operative sevoflurane concentrations were 200-400 times higher than background values for the laryngeal mask airway 1 (1-2 [0-3]) ppbv vs. 404 (278-523 [83-983]) ppbv, respectively, and the tracheal tube 2 (1-3 [0-5]) ppbv vs. 396 (204-589 [107-1735]) ppbv (both p < 0.0001), and returned to background values within 5 min of removal. There were no differences in sevoflurane concentration between devices intra-operatively or after removal. The performance of the proton-transfer-reaction mass spectrometer was identical at the start and end of the 30-day study. We conclude that peri-operative sevoflurane concentration in a modern operating theatre is similar for the laryngeal mask airway and the uncuffed tracheal tube in paediatric patients receiving intermittent positive pressure ventilation. Intra-operative sevoflurane concentrations are five times lower than occupational safety limit requirements, and 1000 times lower 5 min after removal of the airway device with the patient awake. The proton-transfer-reaction mass spectrometer has potential for monitoring air quality in the operating theatre.

[Physical training as interval or continuous training in chronic heart failure for improving functional capacity, hemodynamics and quality of life--a controlled study]

We conducted a three-week randomized trial comparing the improvement of functional capacity by exercise training in chronic heart failure by the steady-state (EF 27.3%, n = 20) and the interval modus (EF 29.3%, n = 20) with a control group (EF = 26.6%, n = 10). Minimal EF was 10%, the lowest maximal oxygen consumption was 9.3 ml/kg/min and the lowest cardiac output was 1.9 l/min; 9 patients had been evaluated for HTX. VO2 at the anaerobic threshold and at maximal exercise increased in the continuous exercise group by 1.4 or 1.6 ml/kg/min, respectively, corresponding to an increase of 13.7% (p < 0.05) and 9.3% (p < 0.05). In the interval training group the increase was 1.3 and 1.5 ml/kg/min corresponding to 14% (p < 0.05) and 8.1% (p < 0.05). Continuous short-term exercise had no impact to central hemodynamics as pulmonary artery pressure (PA), capillary wedge pressure (pc), cardiac index (CI) or stroke volume index (SVI), whereas after interval training a significant increase at maximal exercise could be seen in CI (p < 0.05) and SVI (p < 0.01) with a concomitant drop in systemic peripheral resistance (p < 0.05) compared to the steady-state modus. Interval training was further characterized by a higher short-term but lower mean work load with a significantly smaller increase in lactate. Quality of life was improved according to the SF-36 questionnaire in both training groups but the psychologic sum factor was three times as high, increasing to 24.2% in the steady-state exercise group. It can be concluded that clinically stable patients with heart failure and even those already having been evaluated for cardiac transplantation profit from short-term physical training. Both training modalities seem equally suited to improve functional capacity. However interval training leads to more pronounced improvement in hemodynamics compared to the steady-state exercise, whereas the later had a greater impact on psychological well-being and quality of life. Patients with heart failure and severe peripheral deconditioning tolerate higher workloads with more peripheral stress by an interval training modus. Long-term training modalities need to be established to further improve and stabilize functional status.

[Ultrasound diagnosis of the elbow joint in fracture of the head of the radius]

Imaging guidelines have been proposed by the German Society of Ultrasonography (DEGUM, 1996) for the locomotor apparatus using five standardized sections of the elbow that allow a reproducible presentation of the surrounding soft tissues and cortical landmarks of this joint. Intra-articular fractures form a variable amount of hematoma, which is easily detected by ultrasound using the proposed standardized sectional planes. Ultrasonography is a cost-effective, easy-to-use and radiation-free method to exclude intra-articular fractures of the elbow. Intra-articular effusions and effusions besides the radial head are indirect signs of bony involvement. Suspected radial head injuries in children and adults can easily be examined by ultrasound. Detection of intra-articular effusions may then lead to further investigation with magnetic resonance imaging (MRI) when needed. MRI is unnecessary when ultrasonography shows no effusions in elbow injuries.

[Ultrasound determination of leg length]

A diagnostic method is presented for measuring the leg length and the difference in leg lengths with ultrasound. A special device for holding and moving the ultrasound transducer was constructed. The measuring points on the hip, knee, and upper ankle can be visualized with a 5- or 7.5-MHz linear scanner. The measuring device gives the distance of the points in centimeters so that the difference corresponds to the real length of the leg, femur, and tibia. Tests conducted on corpses and clinical examples show that ultrasound in combination with our special device is an ideal method for determining the exact length of the leg. Ultrasound measurement of the leg length offers a reliable, noninvasive, and easily performed method. Because ultrasound is not limited by radiation hazards, our technique can be used for clinical screening.

[Ultrasound examination technique of the elbow and wrist joints]

Ultrasound examination of the elbow and hand is invaluable in diagnostics of acute and chronic joint diseases. Ultrasound is a noninvasive, immediately available procedure without radiation, which should be performed after exploration and clinical examination. It cannot, however, replace radiographic examination because the cortical substance represents a barrier for the ultrasound waves so that bony lesions (i.e., intraosseous tumors or osteomyelitis) cannot be detected. In the diagnosis of periarticular soft tissue lesions and intra-articular changes (loose bodies, intra-articular effusion, or synovitis), ultrasound represents an excellent cost-effective method supplying additional information. The sonographic technique is presented with the standard sectional planes according to the directives given by the working group on the musculoskeletal system of the German Society for Ultrasound in Medicine (DEGUM) issued on 20 January 1996.

[Diseases of the hip joint in childhood and adolescence--ultrasonic differential diagnoses]

A total of 329 children with hip pain were examined by ultrasound, which indicated transient synovitis (n = 161), rheumatoid arthritis (n = 16), tuberculoid arthritis (n = 3), septic arthritis (n = 16), Legg-Calvé-Perthes disease (n = 102), and slipped capital femoral epiphysis (n = 31). Using the standard planes described by DEGUM and DGOOC, it is possible to analyze the joint capsule, the surface of the femoral head, and the periarticular structures. In cases of synovitis or joint effusion, a capsular distension can be diagnosed by ultrasound. This distension is typical in transient synovitis, septic and tuberculoid arthritis, juvenile rheumatoid arthritis, and the onset phase of Perthes disease. Because capsular distension exhibits no significant differences in the various diseases, differentiation is not possible with ultrasound in the absence of osseous abnormalities. In cases with both capsular distension and osseous abnormalities, ultrasound usually allows a differentiation between slipped capital femoral epiphysis and Perthes disease as well as septic and unspecific arthritis.

[Ultrasound imaging of the patellar gliding groove]

Ultrasound is a noninvasive, immediately available procedure without radiation, which should be performed after exploration and clinical examination. It cannot, however, replace radiographic examination because the cortical substance represents a barrier for the ultrasound waves so that bony lesions (i.e., intraosseous tumors or osteomyelitis) cannot be detected. In the diagnosis of periarticular soft tissue lesions and intra-articular changes, i.e., loose bodies, intra-articular effusion, or synovitis, ultrasound represents an excellent cost-effective method supplying additional information and should be performed before using more costly techniques (magnetic resonance imaging). Ultrasound of the femoral patellar groove is limited because of the higher location of the patella. The area of the dorsal patella is not approachable for ultrasound. The sonographic technique is presented with standard sectional planes according to the directives given by the working group on the musculoskeletal system of the German Society for Ultrasound in Medicine (DEGUM) issued on 20 January 1996.

[Possibilities and limitations of ultrasonography in corticotomy/callus distraction]

Sonographic examination can yield additional information free of radiation in the course of corticotomy/callus distraction. The echogenic structures of the cortical structure and the callus between can be scanned at the area of the callus distraction by ultrasound examination. Individual sectional planes are focussed. They are different from the standardized ultrasound examination. Depending on when the corticotomy was performed, the callus between the cortical structures can be visualized sonographically. First it is echo poor, and then it becomes more and more echogenic. The ultrasound examination can give additional information during the first 4 weeks after corticotomy/callus distraction. A deviation of the axis in the area of callus distraction cannot be judged reliably. A sonographically guided division into three stages is possible.

[Standardized sectional planes of the locomotor apparatus]

Comparable to the standardized ultrasound screening of newborns and infants according to Graf's method, the standardized ultrasound examination of the locomotor apparatus has become an important feature in the evaluation of many acute and chronic diseases. The standardized ultrasound examination technique according to the guidelines of DEGUM and DGOOC helps the experienced and inexperienced user to avoid diagnostic mistakes by reproducibly displaying anatomical landmarks. Specific individual planes can be necessary in certain indications. The main advantage in comparison to other diagnostic means (i.e., computed tomography and magnetic resonance imaging) lies in the possibility of dynamic examination, which allows excellent imaging especially in rotator cuff affections. In cases without pathological findings, two standardized planes have to be documented. Otherwise, the pathological finding has to be documented in two standardized planes. The standardized procedure is a useful means for assuring and improving the quality of sonographic examinations of articular and periarticular structures.

Insomnia in depression: differences in objective and subjective sleep and awakening quality to normal controls and acute effects of trazodone

Utilizing polysomnography (PSG) and psychometry, objective and subjective sleep and awakening quality was investigated in 11 drug-free patients (five females, six males) aged 35-75 years (mean age 54.1 +/- 11.4) suffering from nonorganic insomnia (F 51.0) related to a depressive episode (F 32) or recurrent depressive disorder (F 33). as compared with 11 age- and sex-matched normal controls (five females, six males) aged 36-75 years (mean age 53.0 +/- 13.5). PSG demonstrated decreased sleep efficiency, total sleep time (TST), total sleep period (TSP) and sleep stage S2, as well as increased wakefulness during TSP, early morning awakening, sleep latency to S1, S2, S3 and sleep stage S1 in depressed patients. Subjective sleep quality and the total score of the Self-Assessment of Sleep and Awakening Quality Scale (SSA) were deteriorated as were morning and evening well being, drive, mood and fine motor activity right. Evening and morning blood pressure, the O2 desaturation index and periodic leg movement (PLM) index were increased. In a subsequent acute, placebo-controlled cross-over design study, the acute effects of 100 mg of trazodone, a serotonin reuptake inhibitor with a sedative action due to 5-HT2 and alpha1 receptor blockade, were investigated in the patients. As compared with placebo, trazodone induced an increase in sleep efficiency (primary target variable), TST, TSP and SWS (S3 + S4), as well as a decrease in wakefulness during the TSP, early morning awakening and S2. There was no change in rapid eye movement (REM) sleep with the exception of an increase in the REM duration in minutes. Trazodone also caused an improvement in subjective sleep quality, affectivity, numerical memory and somatic complaints. All respiratory variables remained within normal limits. Critical flicker frequency and moming diastolic blood pressure were decreased. The present study demonstrated that depression induced significant changes in objective and subjective sleep and awakening quality, which were counteracted by 100 mg of trazodone, thus suggesting a key-lock principle in the treatment of depression.