2006 OPEN FORUM Abstracts
Effect of Nebulization through Humid-HeatT on Bronchodilator Effect of Albuterol in Stable Asthmatics
David C.
Willms MD, Melissa K. Brown BSRT, RRT-NPS, Jim Spinharney RCP, Marc
Tappen RRT, Jodette Brewer RRT, Sharp Memorial Hospital, San Diego, California.
Background: The
Humid-HeatT, is a heat-moisture exchanger (HME) modified to incorporate
additional water and heat into the appliance. Typical practice precludes giving
nebulized medications through an HME, out of concern that nebulized medication
will be trapped, and not reach the patient.
Bench tests performed by the manufacturer, Gibeck, demonstrated that
significant concentrations of nebulized material did cross over the Humid-HeatT
HME in a laboratory study (Hans Lambert, unpublished study). The ability to
administer nebulized medications on the inspiratory side of such a device would
be a significant advantage, in that it would avoid the need to interrupt the
circuit for each treatment (infection risk), or to place an adapter
'downstream" from the HME (increase circuit dead space). Demonstration of a
biological effect from bronchodilators delivered through the Humid-HeatT HME
would be useful. Due to the difficulty of demonstrating bronchodilator effects
on mechanically ventilated patients, the current study involves stable
spontaneously breathing outpatient asthmatics.
Methods: Baseline spirometry was obtained before and after
administration of Albuterol, using standard American Thoracic Society
technique. If the subject demonstrated a significant bronchodilator response
(defined as a 15% and >300 ml in FEV1) the subject was asked to participate
in the Humid-HeatT portion of the study. Spirometry was repeated 1-2 days
later, with the bronchodilator given by nebulizer (same dose and technique), in
this case with a Humid-HeatT device interposed between the nebulizer output and
the patient. The Humid-HeatT was turned on and the subject allowed to breathe
through the device for 5 minutes before beginning nebulization of Albuterol.
This is to permit the saturation of the Humid-HeatT wick. Values for pre and
post spirometric functions were analyzed to determine if the bronchodilator
response was similar through the Humid-HeatT device.
Results: Two female subjects were
studied age
41 and 58 years. Subject #1 demonstrated a 26% increase in FEV1 post
bronchodilator and a 44% increase in FEV1 post bronchodilator in conjunction
with the Humid-HeatT device. Subject #2 demonstrated a 22% increase in FEV1
post bronchodilator and a 15% increase in FEV1 post bronchodilator in
conjunction with the Humid-HeatT device.
| Subject #1 | FEV1 Pre | FEV1 Post | % Change in FEV1 | ml Change in FEV1 |
| Baseline | 2.32 | 2.93 | 26% | 610 ml |
| HumidHeatT | 2.14 | 3.06 | 44% | 920 ml |
| Subject #2 | FEV1 Pre | FEV1 Post | % Change in FEV1 | ml Change in FEV1 |
| Baseline | 2.36 | 2.88 | 22% | 520 ml |
| HumidHeatT | 2.46 | 2.82 | 15% | 360 ml |
Conclusions: This
pilot study demonstrates a positive bronchodilator response in two patients
with traditional medication delivery, as well as through the Humid-HeatT
device. Further research is needed to ascertain the output of particles in the
respirable range as well as the clinical effectiveness of delivering nebulized
medications through the Humid-HeatT device.