Pulmonary Function Tests (PFT)
Reasons for decreased FVC - ANSWER-Surgical procedure on lung; areas of collapse; conditions making the lungs less expandable (fibrosis, CHF, thickened pleura); obstructive lung disease; problems with the pleural cavity (enlarged heart, fluid in pleura, tumor); restriction of chest wall; inflation/deflation requires all respiratory and accessory breathing muscles.
Reasons for decreased FEV1 - ANSWER-Obstructive defects; emphysema, chronic bronchitis, asthma.
What does it mean if the FVC or FEV1 are reduced in the flow-volume loop? - ANSWER-There is either obstruction or restriction affecting the breathing.
PFTs help determine 7 things: - ANSWER-1. Presence of disease or abnormal lung
function.
- Extent of dysfunction.
- Extent of impairment/disability
- Progression of disease.
- Nature of physiological disturbance.
- Effect or course of therapy.
- Aid clinical prognosis.
Common PFTs - ANSWER-1. Spirometry
- Diffusing capacity
- Body plethysmography
- Bronchial provocation
- Maximal inspiratory/expiratory pressure
- Exercise testing
- Arterial blood gasses
Spirometry - ANSWER-Measures air flow and volumes.
Flow/volume relationship - ANSWER-Peak flow reaches its maximal level somewhere near total lung capacity.
As lung volume decreases, resistance increases due to intrathoracic airway narrowing.
What is the primary function of the lungs? - ANSWER-1. Oxygenation of mixed venous blood.
- Removal of carbon dioxide from mixed venous blood.
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