2006 OPEN FORUM Abstracts
EVALUATION OF PATIENT WORK-OF-BREATHING ON AN ELECTRONIC SIMULATOR AND THE VIASYS AVEA USING ESOPHAGEAL PRESSURE MONITORING
Dan Neifert, Ty Barnett, Lutana Haan RRT,
Background: Esophageal pressure monitoring is used to measure the
work-of-breathing (WOB) in patients. The
Viasys Avea has an option to measure WOB using esophageal pressure monitoring.
The WOB on the Viasys Avea was compared to the WOB on the Hans Rudolph Electronic
Breathing Simulator (HR1101).
Method: A lung model (Bear Model 1000) that includes the pleural
space, was used. The Avea was connected to the lung model with a standard
circuit. An esophageal balloon was placed in the lung model and connected to
the Avea. The lung model was then connected to the HR 1101 with a resistance of
5 cm H2O/L/sec., compliance of 60 mL/cm H2O and a
respiratory rate of 15 breaths per minute. The HR 1101 amplitude (cm H2O) was
changed from 2.0 to 40.0 in multiples of 3.0, simulating an increase in patient
effort. Avea settings: CPAP 5 cm H2O, without pressure support. The
WOB measured by the HR 1101 (WOB HR 1101) and WOB measured by the Avea (WOB
Avea) were recorded.
Results:
Amplitude
2.0; WOB HR 1101 .19 j/L; WOB Avea 02 j/L
Amplitude
5.0; WOB HR 1101 .42 j/L; WOB Avea .12 j/L
Amplitude
8.0; WOB HR 1101 .67 j/L; WOB Avea .2 j/L
Amplitude
11.0; WOB HR 1101 .92 j/L; WOB Avea .29 j/L
Amplitude
14.0; WOB HR 1101 1.17 j/L; WOB Avea .36 j/L
Amplitude
17.0; WOB HR 1101 1.43 j/L; WOB Avea .49 j/L
Amplitude
20.0; WOB HR 1101 1.64 j/L; WOB Avea .53 j/L
Amplitude
23.0; WOB HR 1101 1.93 j/L; WOB Avea .66 j/L
Amplitude
26.0; WOB HR 1101 2.14 j/L; WOB Avea .76 j/L
Amplitude
29.0; WOB HR 1101 2.45 j/L; WOB Avea .86 j/L
Amplitude
32.0; WOB HR 1101 2.69 j/L; WOB Avea .92 j/L
Amplitude
35.0; WOB HR 1101 2.92 j/L; WOB Avea .97 j/L
Amplitude
38.0; WOB HR 1101 3.14 j/L; WOB Avea 1.0 j/L
Amplitude
40.0; WOB HR 1101 3.29 j/L; WOB Avea 1.02 j/L
Conclusion: As the Amplitude on the HR 1101 is increased,
simulating an increase in patient inspiratory effort, the WOB HR 1101 and WOB
Avea increase linearly. However, the difference between WOB HR 1101 and WOB
Avea increases as amplitude increases. This difference may be cause by the way
each system calculates WOB.