Respiratory Muscle Fatigue at Different Breathing Modes

Aalborg University12 enrolled

Overview

The study aims at investigating if time to respiratory muscle fatigue and metabolism are influenced by the pressure wave form mode applied during resistive breathing.

In healthy subjects fitted with a nasogastric double balloon catheter and breathing at a resistance, the investigators will measure time to failure, Borg ratings, VO2, VCO2, flow, esophageal-, gastric- and airway-pressure. This will be done during breathing at either a square wave or triangle wave pressure waveform, in random order and trials separated by \>two days. Further respiratory muscle fatigue will be investigated pre and post intervention by maximal esophageal pressure generation (voluntary and with cervical magnetic stimulation).

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

SINGLE

Enrollment

Conditions

Healthy

Interventions

Square wave breathingOTHER

difference in time to failure from the two breathing modes

Eligibility

Sex: ALLMin age: 18 YearsMax age: 60 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * Healthy men or women * Age ≥18 and ≤60 years * BMI ≥ 20 and ≤30 Exclusion Criteria: * Drug addiction defined as the use of cannabis, opioids or other drugs * Previous and present neurologic (e.g. ataxia), musculoskeletal (e.g. muscular dystrophy) or mental illnesses (e.g. schizophrenia) * History of mechanical ventilation, COVID-19 with respiratory complications, lung cancer * Part of lung resected * Presence of dyspepsia/heart-burn/abdominal pain * Presence of esophageal varices * Presence of liver disease * Presence of esophageal hernia * Pregnancy * Failure to comply with transcranial magnetic stimulation adult safety screen * History of epilepsy, metal implants in head or jaw * Acute or chronic lung diseases, e.g. asthma, COPD, bronchitis etc. * Lack of ability to cooperate

Locations (1)

Mathias Krogh Poulsen

Aalborg, Danmark, Denmark

RECRUITING

Outcomes

Primary Outcomes

Time to task failure (Tlim)

The time (s) from the subject starts to breathe under the experimental condition, and until task failure will be measured. Task failure is defied by either subject intolerance to continue or by lacking ability of the subject to maintain the target pressure and/or timing. From a previous publication (Bellemare and Grassino, JAP, 1982), it is estimated that subjects will reach Tlim between 30min to 1 hour. If breathing is continued after 1 hour, task failure will not happen as breathing can be continued indefinitely.