1. Volume 128, Issue 3, Pages 1331-1338 (September 2005)
Comparison of Respiratory Event Detection by a Polyvinylidene Fluoride Film Airflow Sensor and a Pneumotachograph in Sleep Apnea Patients 
Berry Richard B. , MD, Koch Gary L. , Trautz Steven , Wagner Mary H. , MD 
CHEST 
Volume 128, Issue 3, Pages (September 2005)
DOI: /chest
Copyright © 2005 The American College of Chest Physicians Terms and Conditions

2. Figure 1
An example of a hypopnea with PVDF sensor, pneumotachograph, and esophageal pressure tracings is shown. This hypopnea would qualify as either a hypopnea-1 or hypopnea-2. This view is presented for comparison but was not used for scoring events (see “Materials and Methods” section).
CHEST  , DOI: ( /chest )
Copyright © 2005 The American College of Chest Physicians Terms and Conditions

3. Figure 2
An example of an hypopnea with PVDF sensor, pneumotachograph, and esophageal pressure tracings is shown. This hypopnea would qualify as a hypopnea-2, because the flow reduction was < 50%, but the respiratory event is followed by an arousal. This view is presented for comparison but was not used for scoring events (see “Materials and Methods” section).
CHEST  , DOI: ( /chest )
Copyright © 2005 The American College of Chest Physicians Terms and Conditions

4. Figure 3
An example of an obstructive apnea with PVDF sensor, pneumotachograph (Pneumo), and esophageal (Esoph) pressure tracings is shown. This view is presented for comparison but was not used for scoring events (see “Materials and Methods” section).
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Copyright © 2005 The American College of Chest Physicians Terms and Conditions

5. Figure 4
A Bland-Altman plot of the difference in the apnea-hypopnea-2 indexes for each subject (pneumotachograph-PVDF) plotted against the average of the pneumotachograph AHI and PVDF AHI using the hypopnea-2 definition.
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Copyright © 2005 The American College of Chest Physicians Terms and Conditions

6. Figure 5
The corresponding maximum peak-to-peak deflections of 20 randomly chosen breaths over a range of flow rates for each subject for the pneumotachograph and PVDF sensors are shown. The dotted line is the line of identity. The solid line is the regression line (r = 0.84; p < 0.001).
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Copyright © 2005 The American College of Chest Physicians Terms and Conditions

7. Figure 6
Tracings from the pneumotachograph (pneumo) and PVDF sensors are shown for four patients during periods of variable airflow. As seen from the tracing, the PVDF signal gives a good picture of changes in the magnitude of airflow. The PVDF signal shape does not show the flattening seen in the pneumotachograph signal.
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Copyright © 2005 The American College of Chest Physicians Terms and Conditions

8. Figure 7
The corresponding maximum peak-to-peak deflections of randomly chosen breaths over a range of flow rates for the same subject for the pneumotachograph and PVDF sensor are shown at a temperature of 22°C and 27°C inside the mask. The regression lines are nearly parallel, although the one for the lower temperature is slightly shifted upward.
CHEST  , DOI: ( /chest )
Copyright © 2005 The American College of Chest Physicians Terms and Conditions