Respiratory Muscle Fatigue at Different Breathing Modes

Not Applicable

• Conditions: Healthy

• Registration Number: NCT05393115
• Lead Sponsor: Aalborg University

Brief Summary

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.

Detailed Description

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 Timeline

• Study Start: 2021-10-01
• Study First Submitted: 2022-04-21
• Status Verified: 2022-05
• Study First Submitted QC: 2022-05-24
• Last Update Submitted: 2022-05-24
• Study First Posted: 2022-05-26
• Last Update Posted: 2022-05-26
• Primary Completion: 2022-12-01
• Study Completion: 2022-12-01

Recruitment & Eligibility

• Status: UNKNOWN
• Sex: All
• Target Recruitment: 12

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

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Primary Outcome Measures

Name	Time	Method
Time to task failure (Tlim)	Up to two months between the two different breathing trials (randomized order)	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.

Secondary Outcome Measures

Name	Time	Method
Tidal volume	Up to two months between the two different breathing trials (randomized order)	Tidal Volume (ml) will be measured with a flowsensor (Hans Rudolph) through a pressure box (ICU lab, KleisTek)
Minute ventilation	Up to two months between the two different breathing trials (randomized order)	Minyte ventilation (l/min) will be measured with a flowsensor (Hans Rudolph) through a pressure box (ICU lab, KleisTek)
Respiratory work	Up to two months between the two different breathing trials (randomized order)	Work of breathing (j), will be calculated from outcome measure 2 and 9 (pressure (cmH2O) and insp. and expiratory time (s)). Measured with pressure box (ICU lab, KleisTek)
Insp. and expiratory time	Up to two months between the two different breathing trials (randomized order)	Insp. and expiratory time (s) will be measured with a flowsensor (Hans Rudolph) through a pressure box (ICU lab, KleisTek)
Respiratory muscle pressures	Up to two months between the two different breathing trials (randomized order)	Respiratory muscle pressure will be measured by esophageal and gastric pressure (in cmH2O) using a naso gastric catheter fitted with double balloons (Nutrivent) connected to a pressure sensor (ICU lab, KleisTek).
Metabolism	Up to two months between the two different breathing trials (randomized order)	Energy expenditure calculated from VO2 (ml/min) nad VCO2 (ml/min) with e.g Weir equation. VO2 and VCO2 are measured with Beacon (Mermaid care).
Respiratory rate	Up to two months between the two different breathing trials (randomized order)	Respiratory rate (breaths/min) will be measured with a flowsensor (Hans Rudolph) through a pressure box (ICU lab, KleisTek)
Ratings of perceived exertion	Up to two months between the two different breathing trials (randomized order)	Borg Dyspnea Scale, from 0-10 where 0 is no effort at all and 10 is maximal breathing effort.

Trial Locations

Locations (1)

Mathias Krogh Poulsen; 🇩🇰 Aalborg, Danmark, Denmark