Respiratory Muscles and Work of Breathing in Children

Study Overview
=================
Brief Summary
-----------------
Respiratory muscle testing allows a quantitative assessment of inspiratory and expiratory muscles in children of any age with primary or secondary respiratory muscle impairment, in order to better understand the pathophysiology of respiratory impairment and guide therapeutic management. The use of an invasive technique (esogastric probe) makes it possible to specifically explore the diaphragm, the accessory inspiratory muscles and the expiratory muscles in order to detect dysfunction or paralysis of these muscles, and to estimate the work of breathing in order to better guide the respiratory management. The primary objective of the study is to evaluate the respiratory effort in children with primary or secondary impairment of the respiratory muscles during spontaneous breathing or during mechanical ventilation.

Detailed Description
-----------------
Respiratory muscle testing allows a quantitative assessment of inspiratory and expiratory muscles in children of any age with primary or secondary respiratory muscle impairment, in order to better understand the pathophysiology of respiratory impairment and guide therapeutic management. The use of an invasive technique (esogastric probe) makes it possible to specifically explore the diaphragm, the accessory inspiratory muscles and the expiratory muscles in order to detect dysfunction or paralysis of these muscles, and to estimate the work of breathing in order to better guide the respiratory management. Respiratory muscle testing by means of esogastric measurements may allow assessing the effect of pharmacological treatment by comparing respiratory muscle strength before and after a few months with treatment. Moreover, esogastric measurements can be used to better adapt mechanical ventilation or to determine the possibility of weaning from the respiratory support. The primary objective of the study is to evaluate the respiratory effort in children with primary or secondary impairment of the respiratory muscles during spontaneous breathing or during mechanical ventilation.

Official Title
-----------------
Respiratory Muscles and Work of Breathing in Children

Conditions
-----------------
Neuromuscular Diseases, Congenital Diaphragmatic Hernia, Lung Diseases, Cardiac Diseases, Scoliosis, Diaphragmatic Impairment, Respiratory Muscle Impairment

Intervention / Treatment
-----------------
* Other: Esogastric pressure measurement


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Patients aged less than 18 years old with primary or secondary impairment of respiratory muscles and followed at Necker Hospital Patients under spontaneous breathing or noninvasive or invasive mechanical ventilation Written informed consent Exclusion Criteria: No social insurance Significant psychomotor retardation Absence of cooperation Significant agitation Hemodynamic instability Acute condition or temporary drug treatments that may interfere with the results of the respiratory muscle explorations

Ages Eligible for Study
-----------------
Minimum Age: 0 Years
Maximum Age: 17 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Diagnostic
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Respiratory muscle impairment<br>Minor patients with primary or secondary impairment of respiratory muscles and followed at Necker Hospital | Other: Esogastric pressure measurement<br>* Measurement of work of breathing and respiratory muscles strength using an esogastric catheter. One measurement or before and after (6 months and 1 year) the initiation of a pharmacological treatment in order to assess the effect of the treatment on respiratory muscle function.<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Esophageal pressure-time product (PTPoes) | The integral of the esophageal pressure signal over inspiratory time | Day 0 | 
| Diaphragmatic pressure-time product (PTPdi) | The integral of the transdiaphragmatic pressure signal over inspiratory time | Day 0 | 
| Work of breathing (WOB) | Total work of breathing (WOBt) is calculated (in Joules/L) as the area under the pressure-volume curve, using the Campbell diagram. Elastic (WOBe) and resistive (WOBr) are estimated as the 2/3 and 1/3 of WOBt value, respectively. | Day 0 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Vital capacity | Vital capacity is the maximum amount of air a person can expel from the lungs after a maximum inhalation, using spirometry | Day 0 | 
| Maximal respiratory static pressures | Maximal static inspiratory and expiratory airway pressures | Day 0 | 
| Maximal sniff pressure | Airway pressure during a sniff test | Day 0 | 
| Maximal whistle pressure | Airway pressure during a whistle test | Day 0 | 
| Peak expiratory flow | Maximal flow during expiratory maneuver | Day 0 | 
| Peak cough flow | Maximal flow during cough | Day 0 | 
| Esophageal pressure during sniff | Esophageal pressure measurement during a sniff test | Day 0 | 
| Gastric pressure during sniff | Gastric pressure measurement during a sniff test | Day 0 | 
| Transdiaphragmatic pressure during sniff | Transdiaphragmatic pressure measurement during a sniff test | Day 0 | 
| Crying transdiaphragmatic pressure | Transdiaphragmatic pressure measurement during crying in young children | Day 0 | 
| Gastric pressure during cough | Gastric pressure measurement during a maximal cough maneuver | Day 0 | 
| Twitch transdiaphragmatic pressure | Transdiaphragmatic pressure measurement during cervical magnetic stimulation | Day 0 | 
| Inspiratory muscles tension-time index | Measurement of the tension-time index of the inspiratory muscles | Day 0 | 
| Diaphragmatic tension-time index | Measurement of the tension-time index of the diaphragm | Day 0 | 
| Correlation between the pressure-time product, the work of breathing and the respiratory muscle strength with the disease severity | The pressure-time product of the respiratory muscles, the work of breathing and the respiratory muscle strength will be correlated with disease severity | Day 0 | 
| Correlation between the pressure-time product, the work of breathing and the respiratory muscle strength with polysomnography and gas exchange results | The pressure-time product of the respiratory muscles, the work of breathing and the respiratory muscle strength will be correlated with the polysomnography and gas exchange results | Day 0 | 
| Esophageal pressure-time products in patients with any treatment and in patients with no treatment | The esophageal pressure-time product will be compared between patients with any treatment and patients receiving no treatment | Day 0 | 
| The total work of breathing in patients with any treatment and in patients with no treatment | The total work of breathing (WOBt), which is calculated (in Joules/L) as the area under the pressure-volume curve using the Campbell diagram, be compared between patients with any treatment and patients receiving no traeatment, using the Student t test | Day 0 | 
| Measurement of esophageal pressure during a sniff in patients with any treatment and patients with no treatment | The esophageal pressure during a sniff will be compared between patients with any treatment and patients receiving no treatment | Day 0 | 
| Measurement of the esophageal pressure-time product before and after pharmacological treatment | The esophageal pressure-time product will be compared before treatment, and 6 months and 1 year after pharmacological treatment initiation | 6 months and 1 year after treatment initiation | 
| The total work of breathing before and after pharmacological treatment | The total work of breathing (WOBt), which is calculated (in Joules/L) as the area under the pressure-volume curve using the Campbell diagram, will be compared before treatment, and 6 months and 1 year after pharmacological treatment initiation, using the ANOVA on repeated measures | 6 months and 1 year after treatment initiation | 
| Measurement of the esophageal pressure during a sniff before and after pharmacological treatment | The esophageal pressure during a sniff will be compared before treatment, and 6 months and 1 year after pharmacological treatment initiation | 6 months and 1 year after treatment initiation | 
| Measurement of transdiaphragmatic pressure during a sniff before and after pharmacological treatment | The transdiaphragmatic pressure measurement during a sniff will be compared before treatment, and 6 months and 1 year after pharmacological treatment initiation | 6 months and 1 year after treatment initiation | 
| Adaptation of the respiratory support according to the esophageal pressure-time product values | The esophageal pressure-time product will be measured to guide the respiratory support adaptation | Day 0 | 
| Adaptation of the respiratory support according to the total work of breathing values | The total work of breathing (WOBt), which is calculated (in Joules/L) as the area under the pressure-volume curve using the Campbell diagram, will be measured to guide the respiratory support adaptation | Day 0 | 
| Measurement of the esophageal pressure-time product in patients with weaning success and in patients with weaning failure | The esophageal pressure-time product will be compared between patients with weaning success and weaning failure | Day 0 | 
| Measurement of the total work of breathing in patients with weaning success and in patients with weaning failure | The total work of breathing (WOBt), which is calculated (in Joules/L) as the area under the pressure-volume curve using the Campbell diagram, will be compared between patients with weaning success and weaning failure, using the Student t test | Day 0 | 
| Measurement of the esophageal pressure during a sniff in patients with weaning success and in patients with weaning failure | The esophageal pressure during a sniff will be compared between patients with weaning success and weaning failure | Day 0 | 
| Correlation between the pressure-time product, the work of breathing and the respiratory muscle strength with the gas exchange during weaning trial | The pressure-time product, the work of breathing and the respiratory muscle strength will be correlated with the gas exchange during a weaning trial | Day 0 | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
Respiratory muscle testing, Respiratory muscle strength, Work of breathing, Esogastric pressures, Diaphragmatic dysfunction, Diaphragmatic paralysis