Influence of Different Interfaces on Synchrony During Pressure Support Ventilation in a Pediatric Setting: A Bench Study

Abstract

BACKGROUND: In adults and children, patient-ventilator synchrony is strongly dependent on both the ventilator settings and interface used in applying positive pressure to the airway. The aim of this bench study was to determine whether different interfaces and ventilator settings may influence patient-ventilator interaction in pediatric models of normal and mixed obstructive and restrictive respiratory conditions. METHODS: A test lung, connected to a pediatric mannequin using different interfaces (endotracheal tube [ETT], face mask, and helmet), was ventilated in pressure support ventilation mode testing 2 ventilator settings (pressurization time [Time press ] 50% /cycling-off flow threshold [Tr exp ] 25% , Time press80% /Tr exp60% ), randomly applied. The test lung was set to simulate one pediatric patient with a healthy respiratory system and another with a mixed obstructive and restricted respiratory condition, at different breathing frequencies (f) (30, 40, and 50 breaths/min). We measured inspiratory trigger delay, pressurization time, expiratory trigger delay, and time of synchrony. RESULTS: At each breathing frequency, the helmet showed the longest inspiratory trigger delay compared with the ETT and face mask. At f 30 , the ETT had a reduced T press . The helmet had the shortest T press in the simulated child with a mixed obstructive and restricted respiratory condition, at f 40 during Time press50% /Tr exp25% and at f 50 during Time press80% /Tr exp60% . In the simulated child with a normal respiratory condition, the ETT presented the shortest T press value at f 50 during Time press80% /Tr exp60% . Concerning the expiratory trigger delay, the helmet showed the best interaction at f 30 , but the worst at f 40 and at f 50 . The helmet showed the shortest time of synchrony during all ventilator settings. CONCLUSIONS: The choice of the interface can influence patient-ventilator synchrony in a pediatric model breathing at increased f, thus making it more difficult to set the ventilator, particularly during noninvasive ventilation. The helmet demonstrated the worst interaction, suggesting that the face mask should be considered as the first choice for delivering noninvasive ventilation in a pediatric model.

Oscillation transmission and volume delivery during face mask-delivered HFOV in infants: Bench and in vivo study

“…Face‐mask is the first choice interface to provide non‐invasive ventilation in bigger children and adults . NHFOV has never been studied on clinical ground using interfaces other than nasal prongs or in patients beyond neonatal age.…”

Non‐invasive ventilation practices in children across Europe

“…Wolfler et al include NIV guidelines in their cohort national study, stating that helmets are an optimal CPAP interface. A bench study in a pediatric setting suggested that helmets might offer significantly worse patient‐ventilator synchrony during non‐invasive pressure support ventilation when compared to the face mask, but these authors used a standard ICU ventilator without the air leak compensation software on, which might have contributed to their results …”

Mechanical ventilation for children

“…A recent bench study [22] evaluated how different interfaces and ventilator settings may influence patient-ventilator interaction in pediatric models of normal and mixed obstructive and restrictive respiratory conditions. A test lung, connected to a pediatric mannequin using an endotracheal tube, a face mask, and a helmet, was ventilated in PSV, testing different ventilator settings, randomly applied.…”