2006 OPEN FORUM Abstracts
PERFORMANCE CHARACTERISTICS OF THREE HANDHELD AIRWAY CLEARANCE DEVICES: QUAKE, ACAPELLA AND FLUTTER
Carl Okeson, Ph.D., Kendall
Loomis, B.S., Paul McGowen, RRT Thayer Medical Corporation,
Background: Airway clearance methods such as CPT and The Vest (Hill-Rom, St. Paul , MN ) loosen mucus by providing strong vibration pulses to the airways during both exhalation and inhalation, and allow a wide range of vibration frequencies (i.e. number of vibratory pulses per second). Three handheld airway clearance devices are now available as a supplement to or replacement for CPT or the Vest. When breathed through, the three handheld devices tested here, the Quake® (Thayer Medical, Tucson , AZ ), the Acapella® (green) (DHD Healthcare, Wampsville , NY ), and the Flutter® (Axcan Scandipharm, Birmingham , AL ), generate pressure waves in the airways of the patient to loosen mucus. In this study, the three handheld devices were compared according to three key performance criteria: pressure wave frequency (i.e. how many pressure pulses are delivered to the lungs per second), mean pressure wave amplitude (i.e. the average strength of the pressure pulses) during exhalation, and mean pressure wave amplitude during inhalation.
Method: Three of each device (n=3) were evaluated at three different settings (handle turning at 30, 60 and 120 RPM for the Quake; counterclockwise, midpoint, and clockwise dial settings for the Acapella; 0° (horizontal), 20° and 40° alignments for the Flutter). The devices were attached via 22 mm respirator tubing to a modified Harvard Breathing Apparatus (Holliston, MA) simulating tidal breathing of 1500 mL and 1000 mL at 12 breaths/minute and 1:1 I:E. Tidal volumes of 1500 mL and 1000 mL were used to mimic the deeper breathing, per manufacturer's instructions, performed by patients when using handheld devices. Resulting pressure waves were measured with Honeywell ( Morris Township , NJ) ASDX series voltage pressure sensors attached to the mouthpieces of the handheld devices. The output of the pressure sensors was collected on a PC and analysed in Excel. Device performances were compared via two-tailed T-tests; p ≤ 0.05 indicated a significant difference.
Results: The results are summarized in the table. The Quake had a wider frequency range than the Acapella and Flutter at the settings evaluated. The best mean amplitudes for the Quake during exhalation (observed at the 30 RPM setting) were significantly higher than the best of the Acapella (at the midpoint setting) and the Flutter (at 0°) at both the 1500 mL and 1000 mL tidal volumes. The Quake was the only device that provided vibratory pulses during inhalation.
Conclusion: Under the conditions evaluated, the Quake offered both greater flexibility in pressure wave frequency and stronger pressure pulses than both the Acapella and Flutter during the entire breathing cycle. These stronger pressure pulses likely translate into greater vibration of patients' airways. By providing strong vibratory pulses during both exhalation and inhalation with a wider range of vibration frequencies, the Quake best mimics the performance of CPT or The Vest.
|Performance Characteristics (SDs in Parentheses)||Quake||Acapella||Flutter|
|Frequency Range : Min - Max (Pulses/Second)||6.1 - 23.5||12.5 - 25.5||12.1 - 16.8|
|1500 mL Tidal Volume:|
|Best Mean Pulse Amplitude - Exhalation (cm H2O)||14.1 (1.2)*||7.4 (0.7)||8.4 (0.3)|
|Best Mean Pulse Amplitude - Inhalation (cm H2O)||9.3 (1.9)*||0||0|
|1000 mL Tidal Volume:|
|Best Mean Pulse Amplitude - Exhalation (cm H2O)||7.8 (0.7)*||4.3 (0.2)||6.5 (0.3)|
|Best Mean Pulse Amplitude - Inhalation (cm H2O)||5.8 (0.9)*||0||0|
|*Significantly higher than other devices; p < 0.05|