2004 OPEN FORUM Abstracts
INOVENT SAMPLE LINE MODIFICATION FOR USE WITH THE VAPOTHERM HUMIDIFICATION SYSTEM.
Michael
Sautel BS RRT Children’s Memorial
Hospital, Chicago, Illinois.
BACKGROUND:
High flow nasal cannula (3-8 LPM) utilizing the Vapotherm
humidication system is common practice in our NICU. For patients
with acute pulmonary hypertensive crisis it is often necessary to
start nitric oxide with the patient already on high flow nasal
cannula. Resistance from the Vapotherm cartridge generates
significant backpressure. Monitoring failure alarms occur on the
INOVent (Datex-Ohmeda), when the sample inlet port of the INOVent is
exposed to > 70 cm H2O pressure. Previously described
fixes for use with CPAP devices include the insertion of the
calibration tee from the inovent to the sample line to vent the
excess pressure in a CPAP circuit. We propose to use this sample tee
to vent pressure when using the Vapotherm with nitric oxide.
METHODS:
The setup for the nasal cannula with nitric oxide has been
previously described in the INOvent Application Update #10 (Use of
Nasal Cannula with the INOvent Delivery System, revised Nov
2000(Datex-Omeda). The flow from this system is hooked up to the
back of the Vapotherm via O2 tubing replacing the cannula. The
Vapotherm circuit is standard with the addition of an infant size
nasal cannula. The calibration tee normally used to calibrate the
inovent is placed between the sample line leur-lock and the inovent
sample inlet. This bleeds excess flow to prevent overpressurizaton
of the sample line. Nasal cannula flow was stepped from 1- 8 LPM in
1 liter increments. Pressure was monitored with a calibrated
manometer teed into the sample line for purposes of this abstract.
Pressure was monitored in the system with and without the
calibration tee in place. Circuit pressure was recorded and a
notation was made when the “monitoring failure” alarm
was activated.
RESULTS:
Without the calibration tee pressure exceeded 70 cm H2O
at 3 LPM with subsequent monitor failure alarm activation. The
following values were measured during patient use with an infant
cannula in place. (*=cm H2O pressure) (BOLD =
monitor failure)
1L
35* 2L 62* 3L 108 * 4L 140
* 5L 168* 6L 172 * 7L 180* 8L
182*. With
the calibration tee in-line pressures remained at <10 cm H2O
at all measured liter flow. Measured levels of NO remained at set
concentration with no fluctuations. NO2 levels were 0.1 or 0.0 ppm
with no fluctuations.
CONCLUSIONS:
Use of the Calibration tee in the sample line keeps the Vapotherm
circuit pressure below the “monitoring failure”
threshold. This allows continuous display of NO and NO2 levels. The
use of the Calibration tee is a safe and effective way to prevent
“monitoring failure” alarms with the INOVent and the
Vapotherm.