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Biomedical subjects

D Köhler

Publications and source records attributed to D Köhler.

At least 55 records · Page 3Linked to original sources
PubMed2001

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.

Chronic Disease↗
PubMed2000

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.

Animals↗
PubMed2000

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.

Adult↗
PubMed2000

[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.

Adult↗
PubMed2000

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.

Chronic Disease↗
PubMed2000

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.

Adult↗
PubMed2000

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.

Airway Resistance↗
PubMed1999

[Withdrawal from the respirator (weaning) in long-term ventilation. The results in patients in a weaning center].

BACKGROUND AND OBJECTIVE: Patients subjected to an increased load and with a decreased capacity of their respiratory muscles may be difficult to wean from mechanical ventilation. Using a weaning strategy with a focus on unloading respiratory muscles may be successful even after long-term mechanical ventilation. In a prospective uncontrolled study, we examined the outcome of our weaning protocol. PATIENTS AND METHODS: Under prolonged mechanical ventilation in outlying intensive care units (44.3 +/- 38.1 days) 232 patients (64.8 +/- 12.7 years, 149 males, 83 females) with the following underlying diagnoses were investigated: chronic obstructive pulmonary disease (54.3%), neuromuscular diseases (16%), thoracic restriction (10.8%), chronic left heart failure (7.3%), postsurgical ventilatory failure (6.9%) and miscellaneous conditions (4.7%). Our weaning strategy was focused on type of mechanical ventilation, endotracheal tubes, non-invasive interface, oxygen supply and transport capacity, body position and home mechanical ventilation, if an increased load or a decreased capacity of the respiratory muscles remained after weaning. RESULTS: Altogether 65% of the patients (n = 152) were weaned in a mean duration of 7.5 days. Intermittent home mechanical ventilation followed in 45 patients (19.4%). In our hospital died 64 patients (27.6%). After a stay of 19.7 +/- 12.2 days in our hospital 72.4% of the patients (n = 168) were discharged. The postdischarge 3-month mortality of the cohort was 36.5%. CONCLUSION: Applying our weaning strategy about 65% of the patients requiring long-term mechanical ventilation were successfully weaned. Weaning was achieved in approximately one fifth of the time previously spent on mechanical ventilation. However, the 3-month mortality of the investigated cohort was 36.3%.

Aged↗
PubMed1999

Scintigraphy for evaluating early aspiration after oral feeding in patients receiving prolonged ventilation via tracheostomy.

OBJECTIVE: In tracheotomised patients the incidence of aspiration is difficult to determine because investigators often apply different criteria. In this study a scintigraphic method was used to visualise feeding aspiration directly and the results were compared with clinical evidence of aspiration. DESIGN: Prospective study in difficult-to-wean patients with tracheostomy. SETTING: Respiratory ICU. PATIENTS AND METHODS: The study population consisted of 62 consecutive patients (16 females, age: 64.1+/-11.1 years). All patients were tracheotomised and had previously been long-term ventilated in other ICUs due to weaning failure. The scintigraphic test was performed during spontaneous breathing. The standard nutrition consisted of a liquid, semi-liquid and solid meal which was labelled with 100 MBq 99mTc-human serum albumin. MEASUREMENTS AND RESULTS: Scintigraphic aspiration (SA) was defined as positive if radioactivity was detected in the bronchial system using a scintillation camera. Furthermore, aspiration was proven clinically (CA). CA and SA yielded identical results in 54 of the 62 patients [10 positive (16%) and in 44 negative (71%)]. CA, but not SA, was seen in 4/62 (6.5%) and SA, but not CA, was found in 4/62 (6.5%) patients. CONCLUSIONS: Our data re-emphasise that aspiration in tracheotomised patients is common (in our study approximately 30%). The scintigraphic method failed to identify all tracheotomised patients with clinically significant aspiration; however, it did suggest that some patients had subclinical aspiration.

Aged↗