2004 OPEN FORUM Abstracts
EVALUATION OF VAPOTHERM™2000I FOR HUMIDIFICATION OF THE NEOPUFF INFANT RESUSCITATOR
Brian
K. Walsh, RRT-NPS, RPFT; University of Virginia Pediatric
Respiratory Medicine; Charlottesville, Virginia
Background: The Neopuff system is used to deliver controlled pressure and
flow for infant ventilation during recessitation. A flow of 5-15 lpm
enters a T-piece. One arm of the T-piece is connected to a mask. The
other arm has a variable leak that provides and regulates PEEP and
can be occluded to provide inflation pressure in the mask. The base
control unit contains an adjustable pressure relief valve to limit
the mask pressure. This evaluation was performed in order to
determine whether the Vapotherm could be used to warm and humidify
the Neopuff output without affecting its operation. The Vapotherm
delivery tube cannot be passed through the Neopuff, so it must be
connected to the patient circuit independently.
Method: The Vapotherm was connected to the patient supply line close
to the Neopuff T-piece via a second T-piece. Flow through the Neopuff base
unit and the Vapotherm were controlled separately. The total flow
through the T-piece was targeted at 15 lpm. The Vapotherm set
temperature was 43ºC. Room temperature was 22ºC and
relative humidity (RH) was 20%. Temperature and RH were measured in
the Neopuff T-piece using a Gibeck sensor system, model 15026, and
absolute humidity calculated from standard equations.
Results.
The table shows RH and temperature under three conditions:
| Flow (lpm) | Relative Humidity (%) | Temperature (ºC) | Absolute Humidity(mg/l) | |
| Neopuff | Vapotherm | |||
| 15 | 0 | 19.6 | 22.8 | 4.0 |
| 7 | 8 | 98.2 | 32.2 | 34.0 |
| 5 | 10 | 99.5 | 36.4 | 39.8 |
Using
room air alone the RH was 20%. By using the Vapotherm, the RH was
increased close to 100%. The temperature of the delivered gas
increased with increasing Vapotherm flow as expected. At 8 lpm
through the Vapotherm (= 53% of the total flow) the temperature was
32ºC, and at 10 lpm (=67% of total flow) the temperature was
36ºC. Water content at this temperature was increased more than
9 fold over room air.
To confirm that
the additional gas stream did not affect Neopuff function, both
outlets of the T-piece were occluded and a manometer used to measure
the airway pressure. This reading was found to be identical with the
pressure displayed on the Neopuff gauge.
Conclusion.
The Neopuff output can be heated and humidified effectively using the
Vapotherm, with a high RH attainable at a delivered gas temperature
of 36ºC. The Vapotherm flow should be connected directly to the
Neopuff circuit close to the T-piece to prevent rainout and
preferably provide 2/3 of the total flow. The Neopuff’s peak
pressure and PEEP regulator operate normally and are not affected by
the Vapotherm extra flow.