[Determination of Hypercapnic Ventilatory Response in COPD Patients]. / Bestimmung der hyperkapnischen Atemantwort bei Patienten mit COPD.

Previous studies showed a reduced hypercapnic ventilatory response (HCVR) in patients with COPD. However, the association between HCVR and COPD GOLD stages is unknown. The measurement of the HCVR is a methodological option to test the function of the breathing feedback cycle. The aim of this feasibility study was to present a new automatic and standardized device (MATAM) to measure and interpret the HCVR. This device determines if exposure to CO2 leads to an adequate increase in breathing frequency and tidal volume. Recordings are performed in a closed system that allows selective changes of each gas component. The minute ventilation (AMV) under hypercapnic stimulation is plotted against the end-tidal CO2 (ETCO2). The HCVR is defined as the linear regression line.28 patients (18 male; 10 female) with COPD GOLD stages 0 to IV were studied. The patients had a mean age of 57 ±â€Š14 (standard deviation) years and a mean BMI of 32 ±â€Š9 kg/m(2). We could show that the HCVR measurement in patients with COPD using MATAM was feasible. Patients with more severe COPD stages had a significantly more reduced HCVR. This could be an indication of reduced chemosensitivity due to a worsening of blood values (pH and pCO2) which affect the central chemoreceptors in the long term. Further studies will be needed to validate the MATAM device for healthy individuals and other patient groups, and for the investigation of standard values.

[Pilot Project: Improved Lung Deposition via a New Nasal Inhalation Procedure]. / Pilotprojekt zur verbesserten Lungendeposition durch ein neues Verfahren der nasalen Inhalation.

INTRODUCTION: Inhaled drugs can only be effective if they reach the middle and small airways. This study introduces a system that combines a trans-nasal application of aerosols with noninvasive pressure support ventilation. METHODS: In a pilot study, 7 COPD patients with GOLD stages II and III inhaled a radiolabeled marker dissolved in water via a trans-nasal route. The mean aerosol particle size was 5.5 µm. Each patient took part in two inhalation sessions that included two application methods and were at least 70 hours apart. During the first session ("passive method"), the patient inhaled the aerosol through an open tube system. The second session ("active method") included pressure support ventilation during the inhalation process. A gamma camera and planar scintigraphy was used to determine the distribution of aerosol particles in the patient's body and lung. RESULTS: The pressure supported inhalation ("active method") results in an increased aerosol lung deposition compared to the passive method. Above all, we could demonstrate deposition in the lung periphery with relatively large aerosol particles (5.5 µm). DISCUSSION: The results prove that the combination of trans-nasal inhalation with noninvasive pressure support ventilation leads to significantly increased particle deposition in the lung.