The high-flow nasal cannula (HFNC) has increased its evidence in patients during pulmonary rehabilitation. These studies hypothesize that the physiological effects of HFNC (positive expiratory pressure, anatomical dead space lavage, thermo-humidification) lead to an increase in exercise time. This is believed to be due to improvements that the device can generate in the respiratory system and muscles. However, the physiological effects of HFNC on respiratory effort and distribution of pulmonary ventilation during exercise are unknown. The aim of this study is to determine the acute effect of high flow nasal cannula on the distribution of pulmonary ventilation and respiratory effort during physical exercise in healthy subjects.
A randomized, cross-over clinical trial in which either HFNC or Sham may be used as an adjunct on a cycle ergometer in random order will be performed to compare the respiratory effort and distribution of pulmonary ventilation continuously. Measurements will be taken in a warm-up, exercise, and recovery phase for both groups.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
NONE
Enrollment
14
HFNC is a device that, in this study, will give the maximum flow (60 L/min), with minimum adjusted temperature (31°C) and FiO2 of 21% or room air.
Laboratorio de Fisiología del Ejercicio, Departamento Ciencias de la Salud, Facultad de Medicina, Pontificia Universidad Católica de Chile.
Santiago, Provincia, Chile
Inspiratory effort
The average esophageal pressure swings during inspiration (ΔPes) defined as the absolute differences between end-expiratory and end-inspiratory Pes over a period of 60 seconds. Measurements will be during warm-up (one minute of five minutes), exercise (minutes: 0-1'; 3-4'; 5-6'), and the recovery phase (minutes: 0-1'; 1-2'; 3-4'; 5-6';7-8';9-10') for both groups.
Time frame: at 3 weeks. Outcome will be measured during the CWRET and will be carried out on different days, separate from approximately 7 days, for a total time frame of 3 weeks maximum per participant. Data will be collected during warm-up, exercise, and recovery
Standard deviation of regional ventilation delay index (RVDsd)
as a measure of temporal distribution of ventilation: defined as the average of 10 breaths representative of the 60 seconds evaluated in each period. Measurements will be during warm-up (one minute of five minutes), exercise (minutes: 0-1'; 3-4'; 5-6'), and the recovery phase (minutes: 0-1'; 1-2'; 3-4'; 5-6';7-8';9-10') for both groups.
Time frame: at 3 weeks. Outcome will be measured during the CWRET and will be carried out on different days, separate from approximately 7 days, for a total time frame of 3 weeks maximum per participant. Data will be collected during warm-up, exercise, and recovery
Work of breathing
The average pressure time product over a minute (PTPmin), defined as the sum of the areas subtended by the Pes waveform during inspiration over 60 seconds. Measurements will be during warm-up (one minute of five minutes), exercise (minutes: 0-1'; 3-4'; 5-6'), and the recovery phase (minutes: 0-1'; 1-2'; 3-4'; 5-6';7-8';9-10') for both groups.
Time frame: at 3 weeks. Outcome will be measured during the CWRET and will be carried out on different days, separate from approximately 7 days, for a total time frame of 3 weeks maximum per participant. Data will be collected during warm-up, exercise, and recovery
Work of breathing per single breath
The average per-breath pressure time product (PTP), defined as the area subtended by the Pes waveform during inspiration in a series of representative and valid breaths divided by the number of breaths (at least five to ten) over 60 seconds. Measurements will be during warm-up (one minute of five minutes), exercise (minutes: 0-1'; 3-4'; 5-6'), and the recovery phase (minutes: 0-1'; 1-2'; 3-4'; 5-6';7-8';9-10') for both groups.
Time frame: at 3 weeks. Outcome will be measured during the CWRET and will be carried out on different days, separate from approximately 7 days, for a total time frame of 3 weeks maximum per participant. Data will be collected during warm-up, exercise, and recovery
Respiratory drive
The average of negative pressure measured 500 ms after the initiation of an inspiratory effort defined as the defection in Pes during the first 0.5 s during inspiration in a series of representative and valid breaths divided by the number of breaths (at least five to ten) over 60 seconds. Also, The average slope of the inspiratory negative Pes swings from the start of inspiration to the minimum pressure (ΔPes/Δt) in a series of representative and valid breaths divided by the number of breaths (at least five to ten) over 60 seconds. Measurements will be during warm-up (one minute of five minutes), exercise (minutes: 0-1'; 3-4'; 5-6'), and the recovery phase (minutes: 0-1'; 1-2'; 3-4'; 5-6';7-8';9-10') for both groups.
Time frame: at 3 weeks. Outcome will be measured during the CWRET and will be carried out on different days, separate from approximately 7 days, for a total time frame of 3 weeks maximum per participant. Data will be collected during warm-up, exercise, and recovery
Tidal Variation (TV) as a measure of variation during tidal breathing
defined as the average of differences between end-expiratory lung impedance (EELI) and end-inspiratory lung impedance (EILV) in 60 seconds for each period evaluated warm-up (one minute of five minutes), exercise (minutes: 0-1'; 3-4'; 5-6'), and the recovery phase (minutes: 0-1'; 1-2'; 3-4'; 5-6';7-8';9-10') for both groups.
Time frame: at 3 weeks. Outcome will be measured during the CWRET and will be carried out on different days, separate from approximately 7 days, for a total time frame of 3 weeks maximum per participant. Data will be collected during warm-up, exercise, and recovery
End-Expiratory Lung Impedance (EELI), as a measure lung aeration
average of end-expiratory lung impedance respectively, in 60 seconds for each period evaluated warm-up (one minute of five minutes), exercise (minutes: 0-1'; 3-4'; 5-6'), and the recovery phase (minutes: 0-1'; 1-2'; 3-4'; 5-6';7-8';9-10') for both groups.
Time frame: at 3 weeks. Outcome will be measured during the CWRET and will be carried out on different days, separate from approximately 7 days, for a total time frame of 3 weeks maximum per participant. Data will be collected during warm-up, exercise, and recovery
Normalized Tidal Variation (TV) as a measure of variation during tidal breathing
defined as the average of differences between end-expiratory lung impedance (EELI) and end-inspiratory lung impedance (EILV) divided by the number of breaths evaluated in each period (60 seconds).Measurements will be during warm-up (one minute of five minutes), exercise (minutes: 0-1'; 3-4'; 5-6'), and the recovery phase (minutes: 0-1'; 1-2'; 3-4'; 5-6';7-8';9-10') for both groups.
Time frame: at 3 weeks. Outcome will be measured during the CWRET and will be carried out on different days, separate from approximately 7 days, for a total time frame of 3 weeks maximum per participant. Data will be collected during warm-up, exercise, and recovery
Normalized End-Expiratory Lung Impedance (EELI)
as a measure lung aeration: defined as the average of end-expiratory lung impedance divided by the number of breaths evaluated in each period (60 seconds). Measurements will be during warm-up (one minute of five minutes), exercise (minutes: 0-1'; 3-4'; 5-6'), and the recovery phase (minutes: 0-1'; 1-2'; 3-4'; 5-6';7-8';9-10') for both groups.
Time frame: at 3 weeks. Outcome will be measured during the CWRET and will be carried out on different days, separate from approximately 7 days, for a total time frame of 3 weeks maximum per participant. Data will be collected during warm-up, exercise, and recovery
Global inhomogeneity index (GI) as a measure of spatial distribution of tidal ventilation
defined as the value of the tidal image in 60 seconds for each period evaluated. Measurements will be during warm-up (one minute of five minutes), exercise (minutes: 0-1'; 3-4'; 5-6'), and the recovery phase (minutes: 0-1'; 1-2'; 3-4'; 5-6';7-8';9-10') for both groups.
Time frame: at 3 weeks. Outcome will be measured during the CWRET and will be carried out on different days, separate from approximately 7 days, for a total time frame of 3 weeks maximum per participant. Data will be collected during warm-up, exercise, and recovery
Center of ventilation (COV), dorsal fraction of ventilation (TVd) and anterior-to-posterior ventilation ratio (Impedance ratio), most dorsal region of interest (ROI4) (TVroi4), as a measure of ventilation distribution influenced by gravity.
defined as the value of the tidal image in 60 seconds for each period evaluated. Measurements will be during warm-up (one minute of five minutes), exercise (minutes: 0-1'; 3-4'; 5-6'), and the recovery phase (minutes: 0-1'; 1-2'; 3-4'; 5-6';7-8';9-10') for both groups.
Time frame: at 3 weeks. Outcome will be measured during the CWRET and will be carried out on different days, separate from approximately 7 days, for a total time frame of 3 weeks maximum per participant. Data will be collected during warm-up, exercise, and recovery
Dyspnea and leg fatigue
: using Modified Borg Scale (0 - 10 points) for each period evaluated warm-up (one minute of five minutes), exercise (minutes: 0-1'; 3-4'; 5-6'), and the recovery phase (minutes: 0-1'; 1-2'; 3-4'; 5-6';7-8';9-10') for both groups.
Time frame: at 3 weeks. Outcome will be measured during the CWRET and will be carried out on different days, separate from approximately 7 days, for a total time frame of 3 weeks maximum per participant. Data will be collected during warm-up, exercise, and recovery
Heart rate
using a pulse oximetry for each period evaluated warm-up (one minute of five minutes), exercise (minutes: 0-1'; 3-4'; 5-6'), and the recovery phase (minutes: 0-1'; 1-2'; 3-4'; 5-6';7-8';9-10') for both groups.
Time frame: at 3 weeks. Outcome will be measured during the CWRET and will be carried out on different days, separate from approximately 7 days, for a total time frame of 3 weeks maximum per participant. Data will be collected during warm-up, exercise, and recovery
Pulse oxygen saturation
using a pulse oximetry for each period evaluated warm-up (one minute of five minutes), exercise (minutes: 0-1'; 3-4'; 5-6'), and the recovery phase (minutes: 0-1'; 1-2'; 3-4'; 5-6';7-8';9-10') for both groups.
Time frame: at 3 weeks. Outcome will be measured during the CWRET and will be carried out on different days, separate from approximately 7 days, for a total time frame of 3 weeks maximum per participant. Data will be collected during warm-up, exercise, and recovery
Respiratory rate
using a electrical impedance tomography for each period evaluated warm-up (one minute of five minutes), exercise (minutes: 0-1'; 3-4'; 5-6'), and the recovery phase (minutes: 0-1'; 1-2'; 3-4'; 5-6';7-8';9-10') for both groups.
Time frame: at 3 weeks. Outcome will be measured during the CWRET and will be carried out on different days, separate from approximately 7 days, for a total time frame of 3 weeks maximum per participant. Data will be collected during warm-up, exercise, and recovery
Blood pressure
Using a sphygmomanometer and stethoscope will be evaluated at the beginning (basal), end of the exercise, and during the recovery phase by the same operator.
Time frame: at 3 weeks. Outcome will be measured during the CWRET and will be carried out on different days, separate from approximately seven days, for a total time frame of 3 weeks maximum per participant. Data will be collected during the basal and recovery phase
Comfort scale associated with dispositive
using visual analog likert scale (0-5: 0: "nothing comfortable" to 5: "totally comfortable") evaluated before and at the end of the exercise.
Time frame: at 3 weeks. Outcome will be measured during the CWRET and will be carried out on different days, separate from approximately 7 days, for a total time frame of 3 weeks maximum per participant. Data will be collected during the basal and end-exercise
This platform is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.