Asthma
Conditions
Brief summary
The project will be pursued in our respiratory, autonomic nervous system physiology laboratory (Respiratory, autonomic nervous system physiology laboratory, Department of Pneumology and Intensive Care Medicine, RWTH Aachen University Hospital). Overactivity of the sympathetic nerve activity (SNA) axis with "centrally" increased heart rate and peripheral vasoconstriction is a known phenomenon in patients with systolic heart failure (HF) and has recently been described in patients with primary lung diseases as in chronic obstructive pulmonary disease (COPD) and pulmonary hypertension (PH). Comprehensive studies investigating sympathetic drive in Asthma as one of the major pulmonary diseases are still lacking. Furthermore, the intention of this study is to determine the impact of Nasal High Flow Therapy (NHFT) on SNA and assess respiratory muscle function using state-of-the-art techniques.
Detailed description
Asthma, being one of the major pulmonary diseases affects roughly 300 million people worldwide. This disease leads to airflow obstruction within the lung following chronic inflammation of the respiratory tract, which results in a wide range of symptoms. Overactivity of SNA has been already linked to patients with systolic heart failure and COPD. The investigators postulate that similar pathomechanism is prevalent in Asthma which leads to an overactivity of SNA. Nasal High Flow Therapy (NHFT) is a recently developed form of oxygen therapy that delivers heated and humidified high-flow oxygen and gas mix through a nasal cannula. In comparison to conventional oxygen therapy, NHFT has been proven substantially beneficial due to additional effects like decreased oxygen dilution, increased FRC, dead space washout with CO2 removal, increased mucociliary function and generation of positive end-expiratory pressure (PEEP) which lead to significantly improved breathing mechanics often preventing the need for invasive machine ventilation (IMV) in various acute diseases. Furthermore, these mechanisms lead to the bronchodilation of small airways in primary obstructive pulmonary diseases like COPD. Positive benefits of NHFT, not only during an acute exacerbation but also with long-term stable disease have been already established in COPD. Similar effects could be expected in bronchial Asthma characterized by obstruction of small airways. Thus, using a comprehensive, multimodal approach and state-of-the-art technology, this research project is designed to determine the prevalence, extent and nature of increased SNA in Asthma (AIM 1) and evaluate the impact of NHFT on sympathovagal balance in patients (AIM 2). The project will address the following hypotheses: 1. SNA is increased in asthma patients. 2. NHFT has a positive impact on the sympathetic drive resulting in decreased SNA.
Interventions
None listed
Sponsors
RWTH Aachen University
ResMed
Study design
Observational model
CASE_CONTROL
Time perspective
PROSPECTIVE
Eligibility
Sex/Gender
ALL
Age
18 Years to 75 Years
Healthy volunteers
Yes
Inclusion criteria
* Clinically diagnosed Asthma * Age ≥ 18 * Ability and willingness to give informed consent to participate in the study
Exclusion criteria
* Atrial fibrillation * Active pacing of the heart by a cardiac pacemaker (i.e. no intrinsic heart rate) * Clinically pre-established cardiovascular disease or other pulmonary diseases (e.g. arterial hypertension, systolic heart failure, COPD) * In-patient stay in the hospital within the last 4 weeks prior to the study examination date * Severe polyneuropathy
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Assessments of the sympathetic nerve activity axis (Non invasive) | 1 year | SVB (sympathovagal balance), HRV (Heart rate variability) and dBPV (diastolic blood pressure variability) will be analysed using a 3-lead electrocardiogram (sampling rate 1000Hz) and a continuous non-invasive arterial blood pressure signal (CNAP® technology, sampling rate 100Hz). HRV (ms2 based on continuously recorded variability in RR intervals) and (diastolic) BPV (expressed as mmHg2 based on continuously recorded variability in diastolic BP) will be computed by time domain analysis and by frequency domain analysis and presented as the high frequency component (HF; 0.15-0.4 Hz), low frequency component (LF; 0.04-0.15 Hz), their relative ratio low frequency/high frequency (LF/HF), and the very low frequency component (VLF; 0.0-0.04 Hz) for both HRV and dBPV . Outcome measure: LF/HF ratio of HRV. |
| Assessments of the sympathetic nerve activity axis (Invasive) | 1 year | MSNA will be recorded via a tungsten microelectrode carefully placed in the peroneal nerve. Outcome measure: Burst Incidence (MSNA Bursts /100 beats). |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| OSA severity | 1 year | Outcome measure: Apnea-hypopnea Index/h (AHI /h; Scale 0 - 150 /h with higher values indicating more severe sleep apnea). |
| Determination of PH (pulmonary hypertension) and right HF (heart failure) severity | 1 year | Outcome measure: TAPSE (tricuspid annular plane systolic excursion; mm). |
| Comprehensive lung function and inspiratory muscle function testing as previously described by our group | 1 year | Outcome measure: Sniff nasal pressure (SNIP; cmH2O). |
Countries
Germany
Outcome results
None listed