[Montelukast-free interval before inhalational bronchial allergen provocation]

BACKGROUND

Leukotrienes are potent bronchoconstrictive and proinflammatory mediators in bronchial asthma. In a previous study on 16 subjects with bronchial asthma (two randomized groups) we showed that montelukast (10 mg daily) significantly suppressed allergen provocation with specific allergens (mites and pollen) (p = 0.0005). In a follow-up study we addressed the question as to when montelukast should be discontinued in order to avoid a relevant effect on inhalational bronchial allergen provocation.

METHOD

At the end of the first study montelukast (10 mg daily) was given again to both groups (2 x 8 asthma patients) for 21 days. After a montelukast-free period of one and three days allergen provocation was repeated in the same manner and the results were compared with the historic baseline values without montelukast.

RESULTS

The provocation dose for allergens was reduced by 39% after a montelukast-free period of one day and by 67% after three days. Only after three days was the difference significant (p = 0.017), at which time the control value was nearly reached again.

CONCLUSION

We recommend that montelukast be discontinued at least three days prior to inhalational allergen provocation.

[Influence of an oscillating physiotherapy device (RC-Cornet trade mark) on the regional distribution of the pulmonary aerosol deposition in patients with COPD]

BACKGROUND

The inhalation of ipratropium bromide via a jet nebulizer obtained a significantly higher bronchodilation, if the oscillating physiotherapy device RC-Cornet trade mark was integrated into the exaspiratory limb of the nebulizer. Therefore we investigated the influence of the RC-Cornet trade mark on the central pulmonary radioaerosol deposition as well as the relationship between central and peripheral lung deposition in patients with chronic obstructive lung disease in a controlled study.

METHODS

Lung ventilation scintigraphy was performed routinely in 14 pat. with COPD (Nebulizer: PARI VECTOR trade mark, radioaerosol 500 MBq tin-colloid). At first all pat. inhaled a single breath from the nebulizer, afterwards the lungs were scanned with a planar gamma camera. Both groups (biometric and lung function data were identical) then inhaled another 5 breaths. In group A the RC-Cornet trade mark was inserted into the exaspiratory limb, in group B a normal exaspiratory valve. Once more lung scans were collected. Evaluation of the scans by means of a "region of interest" technique, dividing the lungs in a central and a peripheral area. Measuring of the radioactivity (impulse) per pixel and determination of the penetration index (PI).

RESULTS

The following 5 breaths led to a significant increase of the central aerosol deposition (i. e. decrease of PI) in comparison with the measuring after the first breath in both groups (A 0,41 +/- 0,07 to 0,38 +/- 0,08, p = 0,04; B 0,38 +/- 0,08 to 0,34 +/- 0,11, p = 0,02). However, no difference could be recognized between the groups. No significant difference was seen with respect to the impulses per pixel.

CONCLUSION

Neither the aerosol deposition in the central region of the lung nor the relation between central and peripheral deposition (PI) differs between the both groups. The effect of the RC-Cornet trade mark mentioned in the introduction seems to be caused by physiotherapeutic induced changes of the mucus transport and not by an enhanced central drug deposition.

[Influence of montelukast on inhalational bronchial allergen provocation]

BACKGROUND

Leukotrienes are potent bronchoconstrictive and proinflammatory mediators in bronchial asthma. A randomized, cross-over study on 16 subjects assigned to two groups investigated whether premedication with the leukotriene antagonist montelukast (10 mg daily for 21 days) has a relevant effect on inhalational bronchial allergen provocation.

METHOD

Allergens were inhaled by atomizing commercial provocation solutions in dilutions of 1 : 1000, 1 : 100, 1 : 50, 1 : 10 and 1 : 5 with a nebulizer (Pari). The allergen dose was escalated every 20 minutes until the positive criteria (20 % fall in FEV1, doubling of oscillatory resistance) were met. The provocation tests were performed on days 1, 21 and 42 of the study.

RESULTS

An allergen protective effect of variable magnitude (PD20 increased by a factor of 1.6 to 21) was observed in 12 of the 16 subjects following provocation with pollen and mite allergens. The mean for all 16 patients showed a highly significant increase (p = 0.0005) by a factor of 4.3. The extent of allergen protection cannot be predicted in individual cases and is independent of the chosen allergen and the PD20 without montelukast. However, a significant correlation (p = 0.0016) was found between unspecific bronchial hyperreactivity (histamine) and the PD20. The allergen protective effect of montelukast decreases with increasing unspecific hyperreactivity.

CONCLUSION

We recommend that medication with montelukast be discontinued before allergen provocation because it cannot be predicted in individual cases whether and to what extent montelukast suppresses the immediate reaction following inhalational bronchial allergen provocation.

Survival of mechanically ventilated patients admitted to a specialised weaning centre

OBJECTIVE

Hospital mortality and survival rates of long-term ventilated patients.DESIGN. Retrospective cohort study.

SETTING

Specialised national weaning centre.

INTERVENTION

Protocol-directed liberation from ventilator.

PATIENTS

Four hundred three of 640 patients with prolonged mechanical ventilation (MV) who were admitted to our respiratory intensive care unit (RICU) were studied. MV lasted longer than 2 weeks and patients had failed more than two weaning trials in the referring ICUs. The majority of patients (59.3%) had chronic obstructive pulmonary disease (COPD).

RESULTS

After a mean duration of 41 days of MV prior to transfer, 68% of patients were liberated from the ventilator. In total, 98 of 403 patients (24.3%) died during the stay in our hospital, 305 patients (75.7%) were discharged. Compared to the non-survivors, the survivors were characterised by younger age, longer length of stay in our RICU, lower severity of illness scores at admission, fewer cardiac illnesses and a higher rate of weaning success. In 31.5% of the discharged patients non-invasive MV (NIV) was initiated during the stay at our unit. We gathered follow-up data on 293 patients (96.1%). Post-discharge survival rates were 67.6% at 3 months, 49.4% at 1 year and 38.1% at 3 years. Length of survival was significantly dependent on age, weaning success and main diagnosis (i.e., prognosis in COPD is worse compared to thoracic restriction, neuromuscular disease and others) in the multivariate analysis.

CONCLUSIONS

Difficult-to-wean patients have a high hospital mortality rate and poor long-term prognosis. Age, main diagnosis, severity of illness, weaning success and institution of NIV predict survival.

[Overestimation of hypoxemia]

Extreme mountain climbers and patients with stable but severe ventilatory insufficiency (e.g. obesitas hypoventilation-syndrome, scoliosis) sometimes experience a state of severe hypoxemia without any or only mild subjective disturbances. Organ failure is never observed in these periods. On the other hand there are two well documented studies concerning long term oxygen therapy (LTOT) that have shown in hypoxemic COPD-patients (pO 2 lower then 55 mm Hg) a doubling the life expectancy under oxygen. This contradiction can be elucidated if the influence of oxygen on the ventilation is taken into account. These study patients treated with LTOT all had more or less hypercapnia (hypoventilation) due to an overload of their respiratory pump. Oxygen reduces the ventilation (seen as hypercapnia) which leads to an unloading of the respiratory muscles. Later studies to LTOT found a positive correlation between the extent of stable hypercapnia and life expectancy. In this article the physiopathologic background of this findings are discussed. The main parameter of the regulator for the oxygen transport is not pO 2 but the oxygen content. The oxygen content multiplied by cardiac output determines the extent of oxygen delivery. Many regulatory systems (e.g. polyglobuly or expression of oxygen resistant isoenzymes of the respiratory chain) are involved to compensate the hypoxemia associated with hypoventilation which prevents an organ threatening hypoxia. This pathophysiologic finding has important impact on intensive care medicine, which usually takes only pO 2 into account for therapeutic decisions (e. g. high FiO 2 and high pressure support). This sometimes leads to "overtreatment", with possible harm to the patient.

[Positive pressure ventilation in Cheyne-Stokes respiration]

Cheyne-Stokes respiration (CSR) is found in patients with chronic left ventricular failure and associated with a reduced prognosis. Continuous positive airway pressure (CPAP) improves the survival rate. In this retrospective study we report on the effect of different positive pressure ventilation modes in CSR. The observation period lasted from 1995 - 1999. Inclusion criteria was CSR with a respiratory disturbance index > 10/h whereas > 50 % of the events had to be central and/or mixed. In each patient a 4 week lasting intervention with each of CPAP, Bilevel CPAP in spontan mode (i.e. BiPAP S or BiPAP ST) and BiPAP in controlled mode (i.e. BiPAP T) was performed. Responder were defined by subjective and objective criteria. In total 41 males were included. Responder were distributed as follows: CPAP: n = 13 patients (31.7 %), BiPAP S/ST: n = 9 patients (22.0 %) and BiPAP T: n = 12 patients (29.3 %). In total 7 from 41 patients (17.1 %) rejected a long-term treatment with positive pressure ventilation. The majority of patients with CSR responded to CPAP and BiPAP S/ST mode. Compared to the other responder groups the best quality was reached with BiPAP T. However the latter was performed only by 29 % of the population.

[Late pulmonary manifestation of ovarian and breast cancer--which contribution provide immunohistochemical techniques?]

The two case studies are describing 2 females with tumor-suspicious lung opacities including pleural effusions. Both patients have had a smoking history of more than 20 packyears and both underwent surgery for a breast respectively an ovarian cancer 10/15 years before. Conventional staining of the biopsies does not allow in most cases the differentiation between a primary lung carcinoma or the metastasis of an extrapulmonary tumor. Immunohistochemical techniques can give clues as to the origin of the primary tumor. The contribution of these methods in finding the correct diagnosis in the two presented cases is discussed. The cooperation between clinician and pathologist should be emphasized. The transfer of all important information is essential.

Sexuality in patients with noninvasive mechanical ventilation due to chronic respiratory failure

In patients with chronic respiratory failure (CRF) noninvasive mechanical ventilation (NMV) improves quality of life. We studied some basic issues concerning sexuality in patients with NMV. In 383 patients with NMV for CRF (age, > 40 yr) physiologic data (lung function, blood gases, and exercise) were taken from within the 6 mo period before enrollment. The questionnaire was focused on sexuality after initiation of NMV. Of the patients, 54.3% sent back the questionnaire. NMV was used for 41.1 +/- 27.0 mo. A total of 34.1% of patients were sexually active. Compared with patients receiving NMV, control persons had a higher rate of sexual activity (84%, p < 0.0001) and masturbation rate (13 versus 40%). Sexually active patients had greater VC (2.1 versus 1.8 L), higher FEV(1) (1.4 versus 1.1 L), higher Pa(O(2)) at rest (64.0 versus 60.4 mm Hg), a higher maximal work load (72.0 versus 58.8 W), were younger, and most of them were married or had sexual partners. Changes in sexual activity after NMV initiation were reported to be as follows: "Nothing changed," 46.3%; "less active," 35.8%; "more active," 12.6%; and "fantasy increased," 10.5%. Increased sexual fantasy predominated in men. "Sexually active" patients with NMV had sexual intercourse 5.4 +/- 4.8 times per month. Sexuality in patients receiving NMV for CRF is markedly reduced compared with normal subjects. In half of the patients, sexual activity is influenced by initiation of NMV.

Long term effects of non-invasive mechanical ventilation on pulmonary haemodynamics in patients with chronic respiratory failure

BACKGROUND

It is not known whether long term nocturnal mechanical ventilation (NMV) reduces pulmonary hypertension in patients with chronic respiratory failure (CRF).

METHODS

Pulmonary haemodynamics, spirometric values, and gas exchange were studied in 33 patients requiring NMV due to CRF (20 with thoracic restriction, 13 with chronic obstructive pulmonary disease (COPD)) at baseline and after 1 year of NMV given in the volume cycled mode. Patients with COPD also received supplemental oxygen.

RESULTS

Long term NMV improved gas exchange while lung function remained unchanged. Mean pulmonary artery pressure at rest before NMV was higher in patients with thoracic restriction than in those with COPD (33 (10) mm Hgv 25 (6) mm Hg). After 1 year of NMV mean pulmonary artery pressure decreased in patients with thoracic restriction to 25 (6) mm Hg (mean change –8.5 mm Hg (95% CI –12.6 to –4.3), p<0.01) but did not change significantly in patients with COPD (mean change 2.2 mm Hg (95% CI –0.3 to 4.8)).

CONCLUSIONS

Long term NMV in CRF improves pulmonary haemodynamics in patients with thoracic restriction but not in patients with COPD.

Long term effects of non-invasive mechanical ventilation on pulmonary haemodynamics in patients with chronic respiratory failure

BACKGROUND

It is not known whether long term nocturnal mechanical ventilation (NMV) reduces pulmonary hypertension in patients with chronic respiratory failure (CRF).

METHODS

Pulmonary haemodynamics, spirometric values, and gas exchange were studied in 33 patients requiring NMV due to CRF (20 with thoracic restriction, 13 with chronic obstructive pulmonary disease (COPD)) at baseline and after 1 year of NMV given in the volume cycled mode. Patients with COPD also received supplemental oxygen.

RESULTS

Long term NMV improved gas exchange while lung function remained unchanged. Mean pulmonary artery pressure at rest before NMV was higher in patients with thoracic restriction than in those with COPD (33 (10) mm Hg v 25 (6) mm Hg). After 1 year of NMV mean pulmonary artery pressure decreased in patients with thoracic restriction to 25 (6) mm Hg (mean change -8.5 mm Hg (95% CI -12.6 to -4.3), p<0.01) but did not change significantly in patients with COPD (mean change 2.2 mm Hg (95% CI -0.3 to 4.8)).

CONCLUSIONS

Long term NMV in CRF improves pulmonary haemodynamics in patients with thoracic restriction but not in patients with COPD.

["Epidemiology" of the value of orally administered morphine as therapy of severe pulmonary emphysema of the pink-puffer type]

OBJECTIVES

Patients with severe emphysema from pink puffer type (PPT) are symptom-limited due to dyspnea even at low level of activity. In this study we investigated the clinical effect of oral morphine in this group of patients.

MATERIALS AND METHODS

Based on the analysis of medical records (n = 456 patients) and a currently answered questionnaire (n = 205 patients) we analyzed data of all patients with emphysema being treated from 1995-1999.

RESULTS

Dyspnea improved during the adaptation period on the ward in 59.4% of the whole population being treated with morphine and in 67.7% of the analyzed patients after discharge. Before discharge the treatment with morphine was finished by 38.9% of the population. In the group of long-term survivors approximately 50% of patients continued the treatment. In total, about 10% of the collective finished the treatment due to intolerable side effects. In the 5-year observation period morphine has been increasingly applied in an earlier stage of the disease.

CONCLUSION

In patients with severe emphysema from pink puffer type a trial with morphine is justified. In particular the beneficial effect on dyspnea in the responder group and the acceptable rate of side effects underline this strategy.

[Stabilization of two patients with brittle asthma by inhaled beclomethasone dipropionate with small particle size]

Two patients with brittle asthma whose bronchial obstruction was less variable during treatment with HFA-beclomethasone (HFA-BDP) solution aerosol than with other previous treatments are presented here. In order to evaluate whether this improvement was related to the smaller particle size of the new formulation (MMAD 1.1 mu vs 4 mu with the CFC-formulation) both patients participated in a prospective case study sequence.

METHOD

During a 4 week run-in both patients inhaled 200 micrograms of HFA-BDP (Ventolair) BID from the Autohaler followed by 4 weeks of treatment with 500 micrograms CFC-BDP (Aerobec) BID from the Autohaler in study phase 1 and 4 weeks of treatment with 200 mcg HFA-BDP (Ventolair) BID from the Autohaler in study phase 2. During the entire study period other concomitant medications remained unchanged. The dose of CFC-BDP was chosen to be 2.5 times higher than the HFA-BDP dose to get approximately comparable amounts of intrabronchial deposition. During the study Peak-Flow and concomitant medications were recorded daily.

RESULTS

Both patients showed significantly higher Peak-flow values during treatment with Ventolair (HFA-BDP) than during treatment with AeroBec (CFC-BDP). P-values were p < 0.0001 and p < 0.005 for patient 1 and 2 respectively.

CONCLUSION

At a comparable intrabronchial dose these two cases of brittle asthma showed significant improvements in control of bronchial obstruction with a BDP-formulation of smaller particle size. This is an indicator that smaller airways in the periphery of the lung participate in the inflammatory process leading to bronchial obstruction and that deposition of inhaled steroids in this region could have therapeutic advantages.

[Does the inhalation of a 1% L-menthol solution in the premedication of fiberoptic bronchoscopy affect coughing and the sensation of dyspnea?]

BACKGROUND

Inhalation of l-menthol inhibits cough and has been shown to reduce respiratory discomfort associated with loaded breathing. We investigated the effect of the inhalation of a 1% l-menthol solution in the premedication of fiberoptic bronchoscopy (FB) on the frequency of cough and the irritability of the tracheobronchial mucosa during FB in a blinded, randomized and placebo controlled study.

METHODS

64 pat. (30-78 yrs, 55 males) underwent routine FB. Premediction: atropine and hydrocodone s.c., inhalation of oxybuprocain by means of a jet nebulizer, sedation on demand. Verum-group: inhalation of 3 ml 1% l-menthol-solution. Placebo-group: 3 ml 0.05% l-menthol (to provide the typical smell). Before and after inhalation peak respiratory flow (PEF) was registered, during FB the frequency of cough was measured. The bronchoscopist scored the irritability of the tracheobronchial mucosa using a visual analog scale. The patients answered a questionnaire addressing their perception of dyspnea and cough on the day after FB compared to the day before.

RESULTS

The cough counts didn't show a significant difference between the groups. The irritability of the mucosa was increased in the verum group (main bronchus verum 62.2 +/- 22, placebo 48.6 +/- 23 [mm vissual analog scale, p = 0.03]). Cough and dyspnea reported by the patients decreased on the day after FB significantly compared to the day before (no difference between the groups). The inhalation of 1% l-menthol induced a significant increase of the PEF (verum 307 +/- 103 pre, 329 +/- 84 post [l/min, p = 0.003]) compared to placebo.

CONCLUSIONS

The inhalation of 1% l-menthol did not enhance the tolerability of the FB. However, l-menthol induced a significant increase of the PEF immediately after inhalation. Finally sensation of dyspnea was decreased in both groups at the day post FB.

Serum levels of sulpiride enantiomers after oral treatment with racemic sulpiride in psychiatric patients: a pilot study

Sulpiride (SULP), a substituted benzamide with high selectivity for D2-like dopamine receptors, has a chiral structure and is used in most countries as the racemate. In an open pilot study, we investigated 26 inpatients (13 female, 13 male) with schizophrenic or depressive disorder treated with SULP (mean daily dosage 64-1062 mg) administered orally, either as a monotherapy or as an add-on treatment to a stable and unchanged medication for 3-60 days. Serum levels of total SULP and of its enantiomers were measured by high-performance liquid chromatography (HPLC) procedures. Clinically relevant indicators of hepatic and renal function as well as retrospectively assessed clinical outcome parameters were correlated with serum levels of racemic SULP, L-SULP, D-SULP, and the L:D-SULP ratio. A significant correlation between mean daily dosage and serum levels of SULP, L-SULP, and D-SULP emerged (p < 0.05) which was not influenced by age, gender, diagnosis, hepatic, or renal function. The ratio of L:D-SULP serum levels was <1 (range 0.66-0.97) in all patients. A slight negative correlation between CGI improvement and the ratio of L:D-SULP (p < 0.10) and a positive correlation between racemic SULP concentrations and side-effects at endpoint was found (p < 0.05).

[Value of retrospective assessment of the Epworth Sleepiness Scale after long-term CPAP therapy in obstructive sleep apnea disorder]]

BACKGROUND

Daytime-sleepiness is the main symptom of the obstructive sleep apnoea syndrome. Standarized questionnaires (e.g. the Epworth sleepiness scale = ESS) have become useful diagnostic tools. In this study we investigated wether there is a difference between the estimation of initial "pre-treatment" daytime sleepiness (by ESS) compared to the retrospective ESS score after implementation of CPAP therapy.

PATIENTS AND METHODS

We included 46 patients (RDI 39/h +/- 20.2, CPAP pressure 8 cm/H2O +/- 1.7, daily use of 5.8 h +/- 1.8, RDI with CPAP 7.6/h +/- 5.3). We examined the ESS score before CPAP-therapy (ESS-base) in comparison to the retrospective estimation of the initial conditions after one year of CPAP-therapy (ESS-retro).

RESULTS

There was no statistical significant difference between ESS base (11.7 +/- 4.6) and ESS-retro (12.7 +/- 5.2). ESS decreased to 5.4 +/- 3.7 by CPAP-therapy (p < 0.01).

CONCLUSION

From a chronological point of view ESS is a consistent parameter of daytime sleepiness. Hence, the retrospective estimation of pre-CPAP ESS can be considered as a useful diagnostic tool.

Inhaled isotonic alkaline versus saline solution and radioaerosol clearance in chronic cough

The aim of the present study was to test the influence of inhaled isotonic Ems salt (brine from the spa of Bad Ems, Germany) compared to isotonic saline on radioaerosol clearance (RC) in patients with chronic cough. Ems salt is an alkaline solution (pH 8.0-9.0) containing largely bicarbonate ions rather than the chloride ions present in isotonic saline (pH 6.4). RC was assessed with a radioaerosol technique using technetium-99m albumin in supine patients. After a 30-min baseline measurement of RC according to a single blind and randomized design, patients inhaled Ems salt (n=22, 20-77 yrs) or isotonic saline (n=21, 34-72 yrs) via a jet nebulizer (Pari Boy) for 10 min and were scanned for an additional 30 min. There was no difference between the two groups before intervention in terms of deposition pattern, lung function and baseline RC rate. After inhalation of Ems salt, the RC rate (1/tau) improved significantly from 0.15+/-0.14 (mean+/-SD) to 0.53+/-0.70 L.h(-1) (p<0.005); no change was found after isotonic saline (0.13+/-0.13 to 0.08+/-0.09 L.h(-1), NS). Voluntary coughs performed after 60 min had no effect on the RC rate. However, in the Ems salt group, significantly more patients reported an inhalation induced cough. Compared to the Ems salt patients, who did not cough during and after inhalation, the RC rate in the cough group was enhanced significantly (0.10+/-0.12 versus 0.73+/-0.83, p=0.017), this effect being seen more frequently in females (p=0.003). It is concluded that Ems salt improves radioaerosol clearance significantly in patients with chronic cough. The underlying mechanism, regarding whether induced cough, increased water content in the mucus or enhanced ciliary beat frequency is the leading cause of Ems salt action, remains unclear.

Prevalence of deep-vein thrombosis of the leg in patients with acute exacerbation of chronic obstructive pulmonary disease

Acute exacerbation of chronic obstructive pulmonary disease (COPD) is associated with dyspnea and, consequently, reduced mobility. Immobility is a recognized risk factor of deep-vein thrombosis (DVT), but few data exist regarding the prevalence of DVT in patients with acute exacerbation of COPD. Real-time B-mode ultrasonography (US) is a noninvasive screening method for the diagnosis of DVT. We therefore used US to investigate the prevalence of DVT in patients with an acute exacerbation of COPD. In a prospective cohort study, 196 patients with COPD were studied [110 males, 86 females, age: 66.9 +/- 9.1 years, weight: 63.5 +/- 12.7 kg, forced expiratory volume in 1 s (FEV1): 0.7 +/- 0.2 liters, and a ratio of FEV1 to vital capacity (VC): 37 +/- 6%] in a respiratory intensive care unit on the day of admission. Patients with reduced mobility due to other disease were excluded. All US were performed by one experienced person with a 5-MHz linear scanner. The views of the lower extremity were subdivided into three segments: (1) the common femoral, (2) superficial femoral veins including the long saphenous vein and (3) the popliteal vein. In 21 of 196 COPD patients (10.7%), DVT were demonstrated; 18 of these were asymptomatic. Bilateral DVT were not found. In 6 patients, additional diagnoses were: Baker's cyst (n = 3), inguinal lymph node (n = 1) and knee joint effusion (n = 2). There were no differences between patients with and with DVT with respect to age, hemoglobin, PO2, PCO2, pH, FEV1, VC or dyspnea scale. DVT in the lower extremity, which was not detectable on clinical examination, was relatively common in patients with an acute exacerbation of COPD. All clinical variables measured (age, weight, dyspnea scale, lung function, hemoglobin, hematocrit and blood gases) failed to predict patients more likely to have DVT.

Effect of nasal-valve dilation on obstructive sleep apnea

OBJECTIVE

Nasal-valve dilation reduces nasal resistance and increases air flow. It is possible that this mechanism prevents hypopharyngeal collapse and sleep apneas. We investigated the effect of a plastic device (Nozovent; Prevancure AB; Västra Frölunda, Sweden)-which dilates the nasal valve-on patients with obstructive sleep apnea (OSA).

DESIGN

Prospective interventional study.

SUBJECTS

Twenty-six consecutive patients with OSA were included (22 men; mean +/- SD age, 54.8+/-11.3 years; respiratory disturbance index [RDI], 34.4+/-18.5 events/h; body mass index, 31.6+/-5.7 kg/m(2)).

INTERVENTION

The nasal dilator was inserted during sleep into the nares and fitted to exert a dilating force on the nasal valves by means of its elasticity.

MEASUREMENTS

Polysomnographic studies were performed before and after 1 month of treatment. A responder is defined as one with a reduction in RDI to < 50% of the baseline value and RDI of < or =10 events/h during treatment.

RESULTS

Five patients dropped out. As a result, only 21 patients were analyzed. Four patients responded, and 17 patients were nonresponders. In the whole population, neither the mean values for respiration during sleep nor sleep staging changed significantly with the device.

CONCLUSIONS

The investigated nasal dilator had no effect on sleep-related breathing disorders in patients with moderate to severe OSA. The reduction in nasal resistance does not prevent hypopharyngeal obstruction.

Immediate intraoral adaptation of mandibular advancing appliances of thermoplastic material for the treatment of obstructive sleep apnea

BACKGROUND

In the treatment of obstructive sleep apnea (OSA), mandibular advancing devices (MAD) are usually individually fabricated on plaster casts of both jaws from polymethyl-methacrylate. The potential disadvantages of these devices are (1) the costs and (2) the time required to construct the device.

OBJECTIVE

In this study, the efficacy and feasibility of a cheap MAD consisting of thermoplastic material (SnorBan((R))), which can be directly moulded intraorally, were evaluated.

METHODS

In a prospective study, the effect of an MAD consisting of thermoplastic material was investigated in 22 consecutive patients with OSA [respiratory disturbance index (RDI) 32.6 +/- 18.4/h]. Polysomnographic sleep was recorded prior to treatment and after 3 months of treatment with the MAD.

RESULTS

Three of the 22 patients who did not tolerate the MAD were excluded from the analysis, whereas 11 patients were classified as responders. In the responder group, the mean RDI decreased from 27.6 +/-7.3 to 7.3 +/- 2.9 (p < 0. 01), correspondingly the sleep quality and the Epworth Sleepiness Scale improved (p < 0.05). Eight patients proved to be non-responders without relevant changes for the measured parameters.

CONCLUSIONS

In 50% (11 of 22) of the patients, the MAD improved the OSA to a clinically relevant degree. In contrast to the majority of established MAD, the MAD investigated is cheap and immediately adaptable and thus a feasible strategy to 'screen' the efficacy of this therapeutic principle. Thus the construction of unnecessary MAD is avoided.

Effect of non-invasive mechanical ventilation on sleep and nocturnal ventilation in patients with chronic respiratory failure

BACKGROUND

Chronic respiratory failure (CRF) is associated with nocturnal hypoventilation. Due to the interaction of sleep and breathing, sleep quality is reduced during nocturnal hypoventilation. Non-invasive mechanical ventilation (NMV), usually performed overnight, relieves symptoms of hypoventilation and improves daytime blood gas tensions in patients with CRF. The time course of the long term effect of NMV on sleep and breathing during both spontaneous ventilation (withdrawing the intervention) and NMV was investigated in patients with CRF due to thoracic restriction.

METHODS

Fifteen consecutive patients (13 women) of mean (SD) age 57.9 (12.0) years with CRF due to thoracic restriction were included in the study. During the one year observation period four polysomnographic studies were performed: three during spontaneous breathing without NMV-before initiation of NMV (T0) and after withdrawing NMV for one night at six months (T6) and 12 months (T12-)-and the fourth during NMV after 12 months (T12+). Daytime blood gas tensions and lung function were also measured.

RESULTS

Spontaneous ventilation (in terms of mean oxygen saturation) progressively improved (from T0 to T12-) during both REM sleep (24.8%, 95% CI 12.9 to 36.9) and NREM sleep (21.5%, 95% CI 12.4 to 30.6). Sleep quality during spontaneous ventilation also improved in terms of increased total sleep time (26. 8%, 95% CI 11.6 to 42.0) and sleep efficiency (17.5%, 95% CI 5.4 to 29.6) and decreased awakenings (54.0%, 95% CI 70.3 to 37.7). Accordingly, REM and NREM sleep stages 3 and 4 significantly improved. However, the most significant improvements in both nocturnal ventilation and sleep quality were seen during NMV at 12 months.

CONCLUSIONS

After long term NMV both spontaneous ventilation during sleep and sleep quality in patients with CRF due to thoracic restriction showed evidence of progressive improvement compared with baseline after withdrawal of NMV for a single night at six and 12 months. However, the greatest improvements in nocturnal ventilation and sleep were achieved during NMV at 12 months.

Heterologously overexpressed, affinity-purified human meprin alpha is functionally active and cleaves components of the basement membrane in vitro

Meprins are astacin-like metalloproteases of renal and intestinal epithelia and embryonic neuroepithelial cells. The full length cDNA of the human meprin alpha subunit has been overexpressed in baculovirus-infected insect cells yielding the tetrameric proprotein which could be proteolytically activated and affinity-purified to homogeneity. Recombinant meprin alpha hydrolyzes the synthetic substrate N-benzoyl-tyrosyl-p-aminobenzoic acid (PABA-peptide) and cleaves by limited proteolysis the basement membrane constituents laminin 1 and laminin 5. This supports a concept that meprin alpha, when basolaterally secreted by human colon carcinoma epithelial cells, increases the proteolytic capacity for tumor progression in the stroma.