Effect of In-Line Intrapulmonary Percussive Ventilation on Respiratory Pressures During Simulated Pediatric Invasive Ventilation

Abstract

Background: Children requiring invasive mechanical ventilation are often administered aerosol and airway clearance therapies. Certain modalities require disconnection from the ventilator and some children may be unable to tolerate interruption of ventilation. Intrapulmonary percussive ventilation (IPV, Percussionaire) therapy is frequently used as it delivers both aerosol and airway clearance. A new in-line adapter (True IPV in-line adapter) that remains in the ventilator circuit allows for therapy during ventilation without disconnection. The aim of the study was to evaluate the effects of IPV used with the in-line adapter on respiratory pressures using an in-vitro pediatric lung model and ventilator.

Methods: A ventilator (Servo-i, Maquet) was connected in series to a dual limb circuit, 5.5 pediatric endotracheal tube with cuff inflated, flow analyzer, and test lung (ARDS conditions: resistance Rp20, compliance 10 mL/mbar). The adapter was placed in the inspiratory limb of the circuit at the Y-piece. Ventilator settings: RR 20 breaths/min, V_T 100, PEEP 10 cm H₂O, inspiratory time 1 in volume control (VC), pressure regulated volume control (PRVC), and pressure control (PC) modes. IPV settings: pressure 25, and easy or hard percussion. The adapter was closed or 50% open. Respiratory pressures (PIP, MAP, PEEP) were measured at baseline and during IPV. The manufacturer recommends opening the adapter during volume ventilation.

Results: Mean PIP and MAP without IPV were 30 cm H₂O and 16 cm H₂O respectively (all modes). During PC ventilation, pressures were least affected. When the adapter was open, PIP and MAP decreased below baseline (all modes). PRVC and VC had greater changes than PC with a closed adapter. Easy settings resulted in higher PIP than hard settings (closed adapter) but the opposite occurred with MAP. PEEP increased with closed adapter by 1-2 cm H₂O and decreased by half when opened (all modes). Percussion setting did not affect PEEP (open/closed adapter). However, easy settings had a higher PIP than hard settings (closed adapter) but the opposite occurred with MAP.

Conclusions: The use of in-line IPV affects respiratory pressures (PIP, MAP, PEEP). These changes were more evident during PRVC and VC than in PC ventilation mode in a closed system. Keeping the adapter closed resulted in an increase in PIP, MAP and PEEP (VC > PRVC > PC). Opening the adapter 50% resulted in decreased PIP, MAP, and PEEP. The findings in this in-vitro model need to be validated in an animal model before clinical recommendations can be made.

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Effect of percussion and adapter setting on PIP and MAP

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Effect of percussion and adapter setting on PEEP