Work of Breathing in Bronchiolitis Under Non-invasive Ventilation

Study Overview
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Brief Summary
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Severe acute viral bronchiolitis is the leading cause of pediatric intensive care admission. The first-line recommended ventilation support is continuous positive airway pressure (CPAP), which reduces the work of breathing (WOB) and improves gas exchange. Although Non invasive Positive Pressure Ventilation (NiPPV) is increasingly used in case of CPAP failure to avoid intubation, no study has yet evaluated if this support could effectively reduce the effort of breathing. Our hypothesis is that NiPPV could reduce WOB more effectively than CPAP alone, and might lead to reduce intubation in the most severe bronchiolitis. The purpose of this study is to compare WOB between CPAP and NiPPV, thanks to esophageal pressure measurement, in infants hospitalized for severe acute bronchiolitis.

Detailed Description
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Severe acute viral bronchiolitis is the leading cause of pediatric intensive care admission. The first-line recommended ventilation support is non invasive ventilation (NIV) with continuous positive airway pressure (CPAP), which has been proved to reduce the work of breathing (WOB) and improve gas exchange. Non invasive Positive Pressure Ventilation (NiPPV) is increasingly used in case of CPAP failure to avoid intubation. Nevertheless, no study has ever evaluated its effectiveness on the discharge of respiratory muscles in severe bronchiolitis. Measurement of esophageal and gastric pressures with an esogastric catheter allows an estimation of WOB thanks to the calculation of the esophageal pressure-time product (PTPes), and a calculation of the transdiaphragmatic pressure (Pdi) as the difference between gastric and esophageal pressures. This minimally invasive technique can be used at the bedside to assess the efficacy of ventilation support and is now increasingly used in Intensive Care Units to assist ventilation-targeted strategies. Our hypothesis is that NiPPV could reduce WOB more effectively than CPAP alone, and might lead to reduce intubation in the most severe bronchiolitis. The main purpose of this study is to compare PTPes/min between CPAP and NiPPV in infants hospitalized for severe acute bronchiolitis. Secondary objectives are i) to compare other parameters of WOB, gas exchanges and breathing pattern in both ventilator supports ii) to compare the rate of patient-ventilator asynchronies in 2 different setting of NiPPV (clinical and physiological) iii) to assess if NiPPV is associated with reduced intubation rate, time under sedation and ventilation, and length of hospitalization as compared to CPAP.

Official Title
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Comparison Between Continuous Positive Airway Pressure (CPAP) and Non Invasive Positive Pressure Ventilation (NiPPV) in Bronchiolitis Under Non- Invasive Ventilation

Conditions
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Severe Viral Bronchiolitis

Intervention / Treatment
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* Other: Esogastric pressures measurement


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Clinical and radiological diagnosis of bronchiolitis Need for non-invasive ventilation support (NiPPV or CPAP) with a modified Wood clinical asthma score (m-WCAS)> 4 and / or hypercapnic acidosis (pH <7.3 and / or pCO2> 50mmHg) Written parental informed consent Exclusion Criteria: Contraindication to nasogastric tube (recent surgery of the esophagus, esophageal malformation at risk of perforation, severe coagulopathy) Absolute or relative contraindication to NIV Respiratory collapse: coma (GCS <12) and / or more than 3 apneas per hour with bradycardia <90 / min and / or SpO2 <90% Pneumothorax Preexisting disorder that may influence WOB Neuromuscular disease Chronic respiratory failure already under NIV or tracheostomy at home No social security

Ages Eligible for Study
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Maximum Age: 6 Months

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

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


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Severe acute bronchiolitis<br>Infants under 6 months admitted in Pediatric Intensive Care Unit for a severe acute bronchiolitis needing NIV (modified Woof clinical asthma score (WCAS) >4 and/or hypercapnic acidosis (pH<7,3 and/or pCO2>50mmHg) | Other: Esogastric pressures measurement<br>* Catheter placement : at least 2 hours after and within 24 hours following the initial ventilation support establishment (CPAP or NiPPV according to usual practice and clinical conditions). 2 periods of measurements : with the initial and with the 2nd ventilation support using a cross-over for each patient. For each period, the first serie of measurements will be carried out without modifying the settings of the support ( clinical setting), and the second one using esogastric pressures by adjusting the settings of the ventilation support in order to obtain an optimal normalization or reduction of the amplitude of the Pes and Pdi deltas (physiological setting). 5 minutes of spontaneous breathing with/without oxygen between period 1 and 2 (depending on the patient's conditions). All measurements will be performed for 5 minutes after a 15 minutes quiet breathing. After measurements, the optimal respiratory support will be continued.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Esophageal pressure-time product per minute (PTPes/min) | Esophageal pressure-time product per minute (PTPes/min) is calculated by the area under the curve of the Pes during inspiration, expressed in cmH2O.s / min. The PTPes/min will be measured under CPAP ( clinical and physiological setting) and under NiPPV ( clinical and physiological setting) during a period of quiet breathing of 5 minutes. | 20 minutes | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Respiratory rate (RR) | Breathing pattern Paramaters will be measured under CPAP (clinical and physiological setting) and NiPPV ( clinical and physiological setting) during a period of quiet breathing of 5 minutes. | 20 minutes | 
| Heart rate (HR) | In pulses per minute Breathing pattern Paramaters will be measured under CPAP (clinical and physiological setting) and NiPPV ( clinical and physiological setting) during a period of quiet breathing of 5 minutes. | 20 minutes | 
| Inspiratory time (Ti) | In sec Breathing pattern Paramaters will be measured under CPAP (clinical and physiological setting) and NiPPV ( clinical and physiological setting) during a period of quiet breathing of 5 minutes. | 20 minutes | 
| Total respiratory cycle time (Ttot) | In sec Breathing pattern Paramaters will be measured under CPAP (clinical and physiological setting) and NiPPV ( clinical and physiological setting) during a period of quiet breathing of 5 minutes. | 20 minutes | 
| Tidal volume (Vt) | In mL Breathing pattern Paramaters will be measured under CPAP (clinical and physiological setting) and NiPPV ( clinical and physiological setting) during a period of quiet breathing of 5 minutes. | 20 minutes | 
| Gas exchange | SpO2 and PtcCO2, in mmHg will be continuously monitored thanks to a pulse oxymeter and transcutaneous capnography (SenTecTM) for 3 hours | 3 hours | 
| Modified Wood's Clinical Asthma Score (m-WCAS) | Modified Wood's Clinical Asthma Score (m-WCAS) is a respiratory failure score that includes 3 levels of gravity corresponding to 5 respiratory distress clinical signs. Values ranged from 0 (best score) to 10 (worst score) | At inclusion and at the end of the measurements, i.e. 3 hours from inclusion | 
| PEdiatric Logistic Organ Dysfunction-2 score (PELOD-2) | Pediatric logistic organ dysfunction score is a specific pediatric multiple organ dysfunction score that includes 10 variables corresponding to 5 organ dysfunctions. Values extend from 0 (best outcome) to 33 (worst outcome). | At inclusion and at the end of the measurements, i.e. 3 hours from inclusion | 
| Work of breathing | Esophageal pressure delta (ΔPES, normal between 5 and 8 cmH2O) Transdiaphragmatic pressure delta (ΔPdi). The Pdi is obtained by subtracting the Pes from the Pgas Pressure-time product of the diaphragm per minute (PTPDdi/min). Paramaters will be measured under CPAP ( clinical and physiological setting) and under NiPPV ( clinical and physiological setting) during a period of quiet breathing of 5 minutes. | 20 minutes | 
| Need for intubation |  | Through study completion, an average of 2 years | 
| Number of days under sedation by Midazolam IV or per os upon hospital discharge |  | Through study completion, an average of 2 years | 
| Number of days under NIV |  | Through study completion, an average of 2 years | 
| Number of days under invasive ventilation |  | Through study completion, an average of 2 years | 
| Number of days in intensive care unit |  | Through study completion, an average of 2 years | 
| Number of days in hospitalization |  | Through study completion, an average of 2 years | 
| Patient-ventilator asynchronies (under NiPPV) | Patient-ventilator asyncrhonies will be analyzed using the flow and pressure curves of the ventilator and the patient (Pes), then classified into 4 groups: auto-triggering (cycle delivered by the ventilator without patient's inspiratory effort), double triggering (2 successive cycles delivered by the ventilator for a single inspiratory effort of the patient), wasted effort (patient inspiratory effort not followed by a cycle delivered by the ventilator), daly asynchronies (advance or delay of the cycle delivered by the ventilator compared to the start of the patient's inspiration or expiration) The percentage of patient-ventilator asynchronies will be analyzed under NiPPV (clinical setting and physiological setting) during a period of quiet breathing of 5 minutes. | Through study completion, an average of 2 years | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Severe acute bronchiolitis, Non-invasive positive pressure ventilation, Continuous positive airway pressure, Work of breathing, Pediatric intensive care