Work of Breathing in Bronchiolitis Under Non-invasive Ventilation

Assistance Publique - Hôpitaux de Paris20 enrolled

Overview

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.

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.

Study Type

INTERVENTIONAL

Interventions

Esogastric pressures measurementOTHER

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.

Eligibility

Sex: ALLMax age: 6 Months

Medical Language ↔ Plain English

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

Outcomes

Primary Outcomes

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.

Time frame: 20 minutes

Secondary Outcomes

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.

Time frame: 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.

Time frame: 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.

Time frame: 20 minutes

Total respiratory cycle time (Ttot)

Time frame: 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.

Time frame: 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

Time frame: 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)

Time frame: 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).

Time frame: 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.

Time frame: 20 minutes

Need for intubation