Abstract
Background: Heated tracheostomy collar (HTC) with different interfaces (direct connection or tracheostomy mask) is used to provide humidification of inspired air to spontaneously breathing tracheostomized children. At our hospital we use a HTC with a blender system (FIO2 0.21). If supplemental O2 is needed, low flow O2 (FIO2 1.0) is given through a tracheostomy ring (t-ring). This is done in the event the HTC circuit becomes disconnected. Sometimes, despite using a maximum flow, the desired O2 saturation is not achieved. We hypothesized increasing the FIO2from the blender, using a direct connection interface, and increasing t-ring flow would result in higher tracheal FIO2s.
Methods: We used a model of a spontaneously breathing tracheostomized child consisting of a 4.0 pediatric tracheostomy tube with cuff inflated (Bivona TTS) inserted into a tracheal model connected in series to a t-piece with O2 analyzer (tracheal FIO2), a filter and a breathing simulator (RR 30, VT 140 mL, I-time 0.7 seconds). Oxygen was delivered through a t-ring attached to the tracheostomy (0-4 L/min), the HTC (15 L/min) at different FIO2s, or with both. We tested 2 different interfaces: a direct connection adapter and a tracheostomy mask. Tracheal FIO2was recorded after 5 minutes and each experiment was repeated 4 times. Interfaces were compared with T-test, and effect of flows and FIO2s were compared with ANOVA. A P < .05 was considered statistically significant.
Results: The direct connect provided higher tracheal FIO2s than trach mask in most occasions. Increasing t-ring O2 flow and increasing HTC FIO2 increased tracheal FIO2.
Conclusions: The HTC used with blender FIO2alone achieved higher tracheal Fi02s than the t-ring in a model of spontaneously breathing tracheostomized child. Increasing t-ring flow increased tracheal FIO2 with HTC FIO2 of 1. The addition of the t-ring O2flow to blender FIO2provided only minimal increases in FIO2. When the blender was set to deliver 1.0 FIO2, the addition of t-ring flow had no impact. In general, there were no significant differences in FIO2between interfaces.
Footnotes
Commercial Relationships: Dr. Berlinski served as principal investigator in studies sponsored by: AbbVie, Allergan, Anthera, DCI, Cempra, Cystic Fibrosis Foundation, National Institute of Health, Novartis, Therapeutic Development Network, Trudell Medical International, Vertex and Vivus. Dr. Berlinski serves as science advisor to the International Pharmaceutical Aerosol Consortium on Regulation and Science (IPAC-RS).
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