Introduction
Sustained pharyngeal inflation (SPI) is an assist positive pressure
ventilation (PPV) maneuver with prolonged inspiration time while peak
inflation pressure (PIP) can be created inside the pharyngolaryngeal
space (PLS). In children with a normal patent airway, the
pressurized-air flow may actively move from upper into the lower airways
and providing the ample time and pressure gradient needed for expand the
airway lumens, alveoli and gas exchange across the air-fluid interface.
Traditionally, this kind of sustained inflation (SI) is accomplished
with a gas flow that delivers via different devices of Ambu-facemask,
bi-nasal prongs, laryngeal mask airway (LMA), or endotracheal tube
(ETT).1-8 This SI has gradually become a widespread
clinical practice. Theoretically, in a relative close space like the
PLS, the levels of created PIP may positively correlate to the durations
of SPI.
“Pharyngeal oxygen with optional close-nose and abdomen-compression
(PhO2-NC-AC)” is a novel model of noninvasive
ventilation (NIV), without using any artificial device such as mask, LMA
or ETT. Which has already demonstrated able to provides adequate
oxygenation and ventilation to assist interventional flexible
bronchoscopy (FB) in children, even in severe asphyxiated
status.9-15 In the setting of PhO2,
the ventilation effect of the “nose-close (NC)” can also create PIP in
the PLS. A prolonged duration of the NC indeed provides a SPI. Closely
measuring and monitoring the levels of these created PIPs are clinical
imperative. However, to our knowledge, there is no study deal with the
SPI durations and associated changes of PIP and image in upper airway of
PLS in pediatrics.
In this study, we use the “PhO2-NC” as a SPI
technique to evaluate and compare the different durations effect on 1)
the created PIP levels in PLS; and 2) the associated changes of airway
image measuring by FB.