Comparison of NIV CPAP Delivery Between a Disposable CPAP Device and an Intensive Care Ventilator in a Simulated Infant Model

Abstract

Background:

Disposable CPAP devices, like the Boussignac valve, are increasingly being utilized in the pre-hospital and emergency department settings. In adult studies, the Boussignac has been found to be ineffective at maintaining stable CPAP, especially during periods of high flow demand. However, the effect in pediatrics is unknown. The aim of this study was to compare NIV CPAP delivery between an intensive care ventilator (Servo-i) and the Boussignac CPAP valve in a simulated infant model.

Methods:

A size 2 infant nasal/oral mask was secured to an infant airway mannikin (Laerdal Medical) and connected to a ASL 5000 lung simulator to simulate a spontaneously breathing infant with bronchiolitis. Compliance and resistance were set at 10 mL/cm H₂O and 60 cm H₂O/L/s, frequency at 36 breaths/min, Ti of 500 ms. Each device was tested at CPAP levels of 5 and 7 cm H₂O with inspiratory efforts (Pmus) of -5, -7.5, and -10 cm H₂O. The Boussignac valve was attached to the nasal/oral mask with the main line tubing attached to an oxygen flow meter. A manometer was attached to the secondary pressure port. Flow was adjusted for until the desired CPAP level was obtained. The Servo-i was set in its respective NIV CPAP mode and attached to the nasal/oral mask with a Fisher & Paykel infant circuit. Scenarios were run for a minimum of 2 min. The first 30 seconds was discarded and the subsequent minute was used for post-run analysis. Pressure swing between peak inspiratory and expiratory pressures were used to assess pressure fluctuation throughout the breathing cycle. MAP was used as an indicator of delivered CPAP. Comparisons were performed by Student t test or Wilcox rank sum test, when appropriate.

Results:

Data are shown below. While there were statistically significant differences in pressure swings between devices, clinically, they are probably irrelevant. MAP was significantly less with the Boussignac compared to the Servo-i under all tested scenarios (P <0.001). MAP averaged 81% and 89% of set CPAP (5 and 7 cm H₂O) with the Boussignac, compared to 101% with the Servo i regardless of set CPAP.

Conclusions:

In this simulated infant model, the Boussignac valve was able to maintain CPAP throughout the breathing cycle similar to an intensive care ventilator and may be an effective alternative in the pre-hospital and emergency department setting. But, clinicians should be aware that set CPAP may be less than delivered CPAP.