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Determining when enhanced pause (Penh) is sensitive to changes in specific airway resistance
David G Frazer1, Jeffrey S Reynolds, Mark C Jackson
1Pathology and Physiology Research Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, West Virginia 26505, USA. dgf1@cdc.gov
Journal of Toxicology and Environmental Health. Part A
|January 18, 2011
Summary
Enhanced pause (Penh) measures airflow changes in whole-body plethysmography, but its use in assessing pulmonary function is debated. This study clarifies the relationship between Penh and thorax/plethysmograph flow patterns to determine its utility in detecting airway resistance changes.
Area of Science:
- Respiratory physiology
- Pulmonary function testing
- Animal models in research
Background:
- Enhanced pause (Penh) is a dimensionless index used to evaluate airflow patterns during respiration in whole-body plethysmography.
- Penh is sensitive to waveform area distribution during exhalation and increases non-linearly with normalized area.
- Previous studies have challenged the reliability of Penh for assessing pulmonary function and airway reactivity.
Purpose of the Study:
- To investigate the relationship between the Enhanced pause (Penh) index and thoracic and plethysmographic airflow patterns.
- To define the conditions under which Penh measurements from whole-body plethysmography can accurately detect changes in specific airway resistance (sRaw).
Main Methods:
- Analysis of airflow patterns and Enhanced pause (Penh) data from whole-body plethysmography in animal models.
- Correlation of Penh values with thoracic and plethysmographic flow waveform characteristics.
- Evaluation of the sensitivity and specificity of Penh in detecting induced changes in specific airway resistance (sRaw).
Main Results:
- The study demonstrates a direct relationship between Penh and the characteristics of thoracic and plethysmographic flow patterns.
- Specific conditions were identified where Penh measurements correlate with changes in specific airway resistance (sRaw).
- The findings provide a clearer understanding of the physiological basis for Penh measurements in plethysmography.
Conclusions:
- The relationship between Penh and plethysmographic flow patterns is crucial for interpreting Penh measurements.
- Under defined conditions, whole-body plethysmograph Penh can be a valuable tool for detecting changes in specific airway resistance (sRaw).
- This research clarifies the utility and limitations of Penh in pulmonary function assessment.
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