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.
*> than other interface (p < .05). #No difference with addition of t-ring flow (p < .0001). &No difference with increasing t-ring flow (p < .0001) View all access options for this article.Results (X ± SD)
T-ring L/min
Blender Fi02
FiO2 (direct connection)
FiO2 (tracheostomy mask)
0
.21
0.211 ± 0.1
0.21 ± 0.3
0
.50
0.46 ± 0.1*
0.418 ± 0.7
0
1.0
0.881 ± 0.9*#
0.789 ± 0.9#
1
.21
0.286 ± 0.4
0.29 ± 0.3
1
.50
0.524 ± 0.1*
0.508 ± 0.3
1
1.0
0.882 ± 0.9*#
0.83 ± 1.7#
2
.21
0.347 ± 0.4
0.372 ± 0.2*
2
.50
0.549 ± 0.5
0.539 ± 1.3
2
1.0
0.877 ± 1.4*#
0.846 ± 1.2#
3
.21
0.41 ± 0.4
0.442 ± 0.4*
3
.50
0.615 ± 0.1*&
0.598 ± 0.3
3
1.0
0.877 ± 0.3#
0.89 ± 2.8#
4
.21
0.458 ± 0.8
0.513 ± 0.5*
4
.50
0.615 ± 0.8
0.613 ± 0.7
4
1.0
0.869 ± 1.5*#
0.832 ± 2.3#
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