Gunther H. Wiest

Evaluation of an auto-CPAP device for treatment of obstructive sleep apnoea

BACKGROUND Auto-CPAP machines used in the treatment of obstructive sleep apnoea (OSA) are designed to vary the treatment pressure automatically in order always to apply the actually needed pressure. Consequently they should be able to achieve at least identical therapeutic effects as conventional constant pressure CPAP with a lower mean treatment pressure. The present study was designed to evaluate the therapeutic efficacy and the treatment pressure of an auto-CPAP machine (REM+auto®, SEFAM) in comparison with a conventional CPAP device. METHODS Following CPAP titration, 16 patients with OSA were allocated to receive conventional CPAP and auto-CPAP treatment under polysomnographic control in a randomised order. After each treatment the patients were asked to assess the therapy using a questionnaire; a vigilance test was also carried out and subjective daytime sleepiness was evaluated using the Epworth Sleepiness Scale (ESS). RESULTS The mean (SD) apnoea/hypopnoea index (AHI) during auto-CPAP treatment was comparable with that during conventional CPAP treatment (4.2 (5.1) versus 3.6 (4.0)). Neither an analysis of sleep architecture nor the arousal index (7.4 (4.1) versus 7.0 (4.3)) revealed any significant differences. Daytime sleepiness measured with the ESS was also comparable (5.3 (3.4) versus 6.5 (4.2)). The vigilance test showed normal values after both treatments in all patients with no significant differences. The mean pressure during auto-CPAP treatment (8.1 (2.9) mbar), however, was significantly higher than that employed in conventional CPAP treatment (7.6 (2.7) mbar; mean difference 0.5 mbar; 95% CI 0.1 to 0.9 mbar; p<0.05). CONCLUSIONS Auto-CPAP was equally as effective as conventional CPAP with respect to therapeutic efficacy. The aim of reducing the treatment pressure with auto-CPAP, however, was not achieved.

A heated humidifier reduces upper airway dryness during continuous positive airway pressure therapy

Upper airway dryness is a frequent side-effect of nasal continuous positive airway pressure (nCPAP) therapy in obstructive sleep apnoea (OSA). In this situation, heated humidification is often used. Alternatively, oily nose drops are frequently applied to relieve dryness. The present study aimed to investigate the efficacy of a heated humidifier in comparison with oily nose drops. Twenty-four OSA patients complaining of serious nCPAP-related upper airway dryness were randomized to 6 weeks of treatment either with heated humidification (HC 100, Fischer & Paykel, Inc., Auckland, New Zealand) or oily nose drops (Colda-Stop, Desitin, Inc., Germany). The patients completed questionnaires on the degree and frequency of upper airway dryness, compliance with nCPAP, intention to terminate nCPAP and comfort during the nCPAP therapy. All 12 patients treated with heated humidification improved in terms of the degree and frequency of upper airway dryness, and reported greater comfort when using the nCPAP device. All patients in the heated humidification group intending to terminate nCPAP therapy because of upper airway dryness persisted with nCPAP on addition of humidification. In contrast, only five out of 12 patients (42%) in the oily nose drops group reported their degree of upper airway dryness to be improved (P = 0.003), only three patients (25%) reported an improvement in the frequency of upper airway dryness (P < 0.001), and only five patients (42%) reported greater comfort when using the nCPAP device with oily nose drops (P < 0.001). In the group using oily nose drops none of the three patients who intended to terminate nCPAP therapy persisted with nCPAP. Heated humidification is highly effective and superior to oily nose drops in reducing the symptoms of upper airway dryness during nCPAP.

Evaluation of a Portable Recording Device (Somnocheck®) for Use in Patients with Suspected Obstructive Sleep Apnoea

Background: Portable recording devices for the diagnosis of obstructive sleep apnoea (OSA) should be carefully evaluated before being used on a routine basis in out-patients. Objective: This study was designed to evaluate the diagnostic accuracy of the new portable recording device, Somnocheck® (SC). Methods: Nocturnal polysomnographies (PSG) and SC recordings were performed simultaneously in the sleep laboratory in 51 patients with suspected OSA, and were analysed manually by a blinded investigator. Results: The apnoea/hypopnoea index (AHI) obtained by manual SC analysis correlated closely with that obtained by PSG (r = 0.98), but the correlation with AHI obtained by automatic SC analysis was markedly lower (r = 0.83). When an AHI ≧10 was defined as indicative of OSA, the sensitivity of manual SC analysis was 0.97 and its specificity 1.00. The sensitivity of automatic analysis was 0.83 and its specificity 0.95. Conclusions: In this experimental setting, the SC showed a very high diagnostic accuracy for the diagnosis of OSA and was able to define its severity precisely. The diagnostic accuracy of manual analysis was found to be superior to that of automatic analysis. Considering the results of this technical evaluation, the SC may also be expected to work reliably when it is used in an ambulatory setting.

Initiation of CPAP therapy for OSA: does prophylactic humidification during CPAP pressure titration improve initial patient acceptance and comfort?

Background: Heated humidifiers (HH) enable effective treatment of upper airway dryness during nasal continuous positive airway pressure (nCPAP) therapy for obstructive sleep apnoea (OSA), but the role of prophylactic use of HH during the initiation of nCPAP treatment has not been studied so far. Objectives: The aim of the present study was to investigate whether prophylactic HH during the initiation of CPAP would result in improved initial patient comfort and acceptance. Methods: In 44 consecutive, previously untreated OSA patients with no history of upper airway dryness, CPAP titration with and without HH was performed on two consecutive nights in a randomised order. The patients were interviewed after each treatment night in order to establish the comfort of the treatment, and, after the second treatment, they were asked which of the two nights they considered more pleasant, and which treatment they would prefer for long-term use. Results: Following CPAP titration with HH, 32 patients (73%) claimed to have had a better night’s sleep than usual (i.e. without CPAP treatment) compared with 33 patients (75%) saying the same following CPAP treatment without HH. For 21 patients (47.7%) treatment with HH was more pleasant, 23 (52.3%) saw no difference or said that treatment without HH was more pleasant. Nineteen patients (43.2%) gave preference to treatment with HH for long-term use, while 25 patients (56.8%) had no preference or said they would prefer treatment without HH. Conclusions: The use of HH during the initiation phase of CPAP treatment was associated neither with an initial improvement in comfort nor with greater initial treatment acceptance.

An auto-continuous positive airway pressure device controlled exclusively by the forced oscillation technique

The forced oscillation technique (FOT) has been demonstrated to be a very sensitive tool for the assessment of upper airway obstruction during nasal continuous positive airway pressure (CPAP) therapy for obstructive sleep apnoea (OSA). The present study was designed to evaluate the therapeutic efficacy of a novel auto-CPAP device based exclusively on the FOT. Following manual CPAP titration, 18 patients with OSA (mean apnoea/hypopnoea index (AHI) 48.0+/-28.1) were allocated to conventional CPAP and auto-CPAP treatment under polysomnographic control in randomized order. The patients were asked to assess their subjective daytime sleepiness using the Epworth Sleepiness Scale (ESS). The mean AHI during auto-CPAP treatment was 3.4+/-3.4 and was comparable with that obtained during conventional CPAP treatment (4.2+/-3.6). The analysis of sleep architecture, the arousal index (6.6+/-2.1 versus 7.3+/-4.4) or the ESS (5.6+/-1.8 versus 7.3+/-4.4) did not reveal any significant differences. However, the mean CPAP pressure during auto-CPAP treatment (0.84+/-0.26 kPa) and in particular the pressure applied in the lateral body position (0.74+/-0.35 kPa), was significantly lower than that employed in conventional CPAP treatment (0.93+/-0.16 kPa, both comparisons: p<0.05). The auto-continuous positive airway pressure device proved equally as effective as conventional continuous positive airway pressure. However, the mean treatment pressure was significantly reduced, especially when patients were sleeping in the lateral position.

Reproducibility of a Standardized Titration Procedure for the Initiation of Continuous Positive Airway Pressure Therapy in Patients with Obstructive Sleep Apnoea

Background: Manual titration of continuous positive airway pressure (CPAP) under polysomnographic control is the method most commonly employed to establish the minimal effective pressure (Peff) for the treatment of the obstructive sleep apnoea syndrome (OSA). To date, however, the reproducibility of Peff titrated in this way has not been investigated in any detail. Objectives: The present study aims to establish the reproducibility of Peff determined by manual titrations of CPAP under polysomnographic control in the sleep lab. Methods: In a group of 50 patients (5 women), with a mean (SD) apnoea-hypopnoea index of 39.3 (21.8), apnoea index of 28.1 (20.9) and oxygen desaturation index of 39.3 (22.6), with newly diagnosed OSA, manual titration of CPAP was performed on two consecutive nights using the following standard titration protocol: starting at 4 mbar, CPAP was increased by steps of 1 mbar at intervals of at least 5 min, until no signs of airway obstruction could be seen, and arousals were no longer elicited. When no airway obstruction was detected over a period of 30 min, the pressure was lowered once during the night in steps of 1 mbar at intervals of at least 10 min, until obstructive events reappeared, whereupon the pressure was again increased as described above, until, once more, no signs of airway obstruction and no arousals occurred. The second titration was carried out in a blind manner, that is the lab technician did not know the results of the first pressure titration. Results: The mean (SD) Peff for all titrations was 8.1 mbar (2.9). A high level of correlation was found between the Peff titrated on the first night and that titrated on the second night (Spearman correlation coefficient = 0.89). In a few individual cases, however, differences of up to 3 mbar were found between Peff on the first night and Peff on the second night. On average, the Peff measured on the second night was 0.5 mbar (SD = 1.3, range: –2.0 to 3.0 mbar) higher than that of the first night. Conclusions: With standardization of the manual titration of CPAP, Peff is readily reproducible. In individual cases, however, a difference of as much as 3.0 mbar between the two titrations is possible.

Sensitivity of a simplified forced oscillation technique for detection of upper airway obstruction

The sensitivity of a simplified variant of forced oscillation technique (FOT) was studied for assessment of dynamic upper airway obstruction during nasal continuous positive airway pressure (nCPAP) therapy for obstructive sleep apnoea (OSA). The airway impedance P[FOT] was measured by FOT and the oesophageal pressure (P(oes)) was recorded during stable stage II sleep in 11 patients with OSA. The CPAP level was initially set high enough to completely abolish upper airway obstruction. To induce gradually increasing upper airway re-obstruction, the CPAP pressure was then lowered stepwise. Thirty six such manoeuvres were analysed, blind, to define the first inspiration at which upper airway re-obstruction was detectable by analysis of P[FOT](t(FOT)) and by P(oes)(t(oes)), respectively. On seven occasions t(FOT) and t(oes) occurred together, in the remaining 29 cases t(FOT) preceded t(oes) with a mean latency of 6.0+/-7.7 (0-32) breath cycles. In no case did t(oes) preceed t(FOT). FOT is a highly sensitive tool for the assessment of incipient upper airway obstruction during nCPAP therapy.

Increased Vascular-Endothelial Growth Factor (VEGF) Tumor Expression and Response to Epidermal Growth Factor Receptor (EGF-R) Inhibitor Erlotinib in Non-small Cell Lung Cancer (NSCLC)

A 37-year-old female never smoker with metastatic large cell carcinoma of the lung had a partial response to a second line palliative therapy with the EGF-R tyrosine kinase inhibitor erlotinib after platinum based first line therapy failed. Molecular analysis of the primary and a liver metastasis did neither find any EGF-R mutation nor an EGF-R amplification. However, both the primary and the metastasis showed an increased gene expression of vascular-endothelial growth factor-A in contrast to normal tissue, which was confirmed by immunohistochemistry. To our knowledge, this is the first report about a high vascular-endothelial growth factor-A expression in the tumor of a patient responding to an EGF-R inhibitor postulating that there might be a link between both tyrosine kinase pathways.

Beatmungspflichtige respiratorische Insuffizienz bei einem 20-jährigen Patienten

D 20-jährige Patient wurde von seinen Eltern zyanotisch und bewusstlos aufgefunden und vom Vater 5 Minuten bis zum Eintreffen des Notarztes Mund-zu-Nase beatmet. Der Notarzt fand einen bewusstlosen Patienten mit Zyanose, pulsoxymetrisch gemessener SaO2 von 68%, Bradypnoe, Hypotonie (Blutdruck 80/40 mm Hg) und auskultatorisch feuchten Rasselgeräuschen über beiden Lungen. Der Patient wurde intubiert, beatmet und unter der Verdachtsdiagnose „anaphylaktischer Schock“ auf unsere Intensivstation gebracht. Die bei Aufnahme angefertigte Röntgenthoraxaufnahme (Abbildung 1) zeigte den Befund eines interstitiellen Lungenödems bei normaler Größe und Konfiguration des Herzens. Bei der körperlichen Aufnahmeuntersuchung fielen eine ausgeprägte Miosis beidseitig (Abbildung 2) und einige frische und ältere Einstichstellen in der linken Ellenbeuge auf. Wir stellten die Diagnose eines nicht kardiogenen Lungenödems bei Verdacht auf Heroinintoxikation. Zunächst war eine kontrollierte Beatmung mit einer FiO2 von 1,0 und die Gabe von Katecholaminen notwendig. Nach parenteraler Gabe von Naloxon wurde innerhalb von 20 Minuten eine arterielle Normotonie erreicht, so dass auf eine weitere Katecholamintherapie verzichtet werden konnte. Später konnten wir bei der qualitativen toxikologischen Untersuchung Opiate im Urin des Patienten nachweisen. Andere Betäubungsmittel, Drogen oder Alkohol konnten in Urin und Serum nicht nachgewiesen werden. 1 Medizinische Klinik I mit Poliklinik und 2 Institut für Diagnostische Radiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg.

Rezidivierende Aspiration, Emesis und Koordinationsstörungen

ZusammenfassungEin Patient wurde wegen rezidivierender Aspirationen und Emesis eingewiesen. Angaben zur Grunderkrankung konnte er nicht machen. Richtungsweisend war aber bereits bei der Untersuchung die ausgeprägte Kleinhirnsymptomatik, die Sprachstörung und die Angabe rezidivierender Aspirationen. Ein 7-jähriger Krankheitsverlauf des M. Fahr war computertomographisch dokumentiert. Die initiale Symptomatik damals bestand in zunehmender Antriebsminderung, zu der erst später neurologische Störungen, v. a. in Form von Koordinationsstörungen hinzutraten. Die Diagnose wurde durch die typischen ausgeprägten Verkalkungen im Bereich der Stammganglien und des Kleinhirns gesichert. Bedeutungsvoll ist, die zunehmende Antriebsminderung der Patienten gegenüber einer Demenz abzugrenzen.Der M. Fahr ist als eine ätiologisch vielfältige Erkrankung anzusehen, in einigen Fällen ist ein Vererbungsmodus beschrieben, eine weitere Ursache kann in einem unbehandelten Hypoparathyroidismus (zumeist bei Zustand nach subtotaler Strumektomie) liegen. Eine Abklärung des Parathormonstoffwechsels ist auch insofern unerlässlich, als eine Korrektur des Kalzium- und Phosphatstoffwechsels gelegentlich zur klinischen Besserung führen kann.In Ermangelung genauer Kenntnisse über die Ätiologie der Erkrankung ist bis heute ein kausaler Therapieansatz nicht möglich. Bei rezidivierendem Verschlucken kann das Krankheitsbild auch internistischen Handlungsbedarf zur Sicherstellung der Ernährungssituation und zur Prophylaxe von Aspirationspneumonien mit sich bringen.