Objective: Sustained pharyngeal inflation (SPI) with pharyngeal oxygen and nose-closure (PhO2 -NC) can create positive peak inflation pressure (PIP) inside the pharyngolaryngeal space (PLS). This study measured and compared the effects of four different SPI durations in the PLS.
Methods: A prospective study, 20 consecutive children aged between 6 months and 3 years old, scheduled for elective flexible bronchoscopy (FB) suspected positive PLS findings were enrolled. SPI was performed twice in four different durations (0, 1, 3, and 5 s) sequentially in each infant. PIP was measured for each SPI in the pharynx, while simultaneously record images at two locations of the oropharynx and supra-larynx. Patient demographic details, PIP levels, lumen expansion scores, and images of PLS were measured and analyzed.
Results: Twenty patients with 40 measurements were collected. The mean (SD) age and weight were 11.6 (9.1) months and 6.8 (2.4) kg, respectively. The measured mean (SD) pharyngeal PIPs were 4.1 (3.3), 21.9 (7.0), 42.2 (12.3), and 65.5 (18.5) cmH2 O at SPI duration of 0, 1, 3, and 5 s, respectively, indicating significant (p<.001) positive correlation. At assigned locations, corresponding PLS images also displayed a significant increase in lumen expansion scores and a number of detected lesions with an increase in SPI duration (p < .004). The mean (SD) procedural time was 5.7 (1.2) min. No study-related complication was noted.
Conclusions: FB utilizing PhO2 -NC as SPI of 1-3 s is a simple, less invasive, and valuable ventilation modality. It provides an adequate PIP level to expand the PLS and improve FB performance in children.
Keywords: Soong's ventilation; flexible bronchoscopy; noninvasive ventilation; pharyngeal pressure; sustained inflation; sustained pharyngeal inflation.
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