pulmonary function tests
Download
Skip this Video
Download Presentation
Pulmonary Function Tests

Loading in 2 Seconds...

play fullscreen
1 / 22

Pulmonary Function Tests - PowerPoint PPT Presentation


  • 147 Views
  • Uploaded on

Pulmonary Function Tests. J.B. Handler, M.D. Physician Assistant Program University of New England. ARDS- adult respiratory distress syndrome DL CO - diffusion capacity for carbon monoxide Ht- height Wt- weight SOB- short of breath Pred- predicted Meas- measured

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Pulmonary Function Tests' - lavender


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
pulmonary function tests

Pulmonary Function Tests

J.B. Handler, M.D.

Physician Assistant Program

University of New England

abbreviations
ARDS- adult respiratory distress syndrome

DLCO- diffusion capacity for carbon monoxide

Ht- height

Wt- weight

SOB- short of breath

Pred- predicted

Meas- measured

PFT- pulmonary function test

ABG- arterial blood gas

Abbreviations
pft s indications
PFT’s: Indications
  • Detect abnormalities and severity of lung function in presence of disease.
    • Monitor course of disease.
  • Baseline pulmonary function prior to surgical, medical or radiation therapy.
  • Differentiation of obstructive vs restrictive disease.
  • Evaluate response to therapy, reversibility.
  • Determine the preoperative risk of thoracic surgery.
lung volumes
Lung Volumes

Images.google.com

lung volumes1
Tidal Volume (TV): amount of air inhaled and exhaled at rest; normal= 500-750 ml.

Inspiratory Capacity (IC): beginning of normal inhalation to maximum inspiration.

Lung Volumes

IC

Images.google.com

lung volumes2
Inpiratory Reserve Volume (IRV): Volume measured from “top” of the TV (point of normal exhalation) to maximum inspiration.

Expiratory Reserve Volume (ERV): Volume measured from the “bottom” of the TV (point of normal inhalation) to maximum expiration.

Lung Volumes

Images.google.com

lung volumes3
Residual Volume (RV): The amount of air left in the lungs following full exhalation to the ERV..

Functional Residual Capacity (FRC) = ERV + RV: amount of gas remaining in the lungs at the end of the tidal volume.

Lung Volumes

Images.google.com

lung volumes4
Vital Capacity (VC): volume of air measured from full inhalation to maximum exhalation

Total Lung Capacity (TLC): summation of the RV + vital capacity.

Lung Volumes

Images.google.com

spirometry
Spirometry
  • Forced Vital Capacity (FVC)- Following full inspiration, patient exhales as rapidly as possible, forcibly and completely- volume of air exhaled is measured; takes 5-6 seconds with majority in 1 second. Wide range of normal (see below).
  • Volume obtained is expressed as a % of predicted normal. Normals are based on volumes obtained from thousands of healthy individuals of similar age, sex, ht and wt and race. Normal 80% of predicted.
spirometry1
Spirometry
  • FEV1:Amount of air forcibly exhaled in the 1st second of the FVC maneuver (80% of FVC volume). Normal 80% predicted; wide range of normal (see below).
  • Volume obtained is expressed as a % of predicted normal. Normals are based on volumes obtained from thousands of healthy individuals of similar age, sex, ht and wt and race. Normal  80% of predicted.
spirometry2
Spirometry
  • FEV1/FVC: Very important ratio; when reduced, helps identify presence of obstructive disease. Percentage reduction correlates with severity of obstruction; normal is 75-80+%. Normal (or ) in patients with restrictive disease.
  • Obstructive airway disease: Asthma, COPD.
  • Restrictive disease: Interstitial lung disease, kyphoscoliosis, pleural disease & others).
peak expiratory flow rate
Peak Expiratory Flow Rate
  • Measured using simple hand held device.
  • Occurs within the first milliseconds of forced expiration and is a measure of maximum airflow rate.
  • Wide variation in normal ranges (age, ht and sex) adult males: 400-700L/minute.adult females: 300-600L/minute.
  • Effort dependent.
  • When abnormal- indicator of large airways obstruction.
peak expiratory flow rate1
Peak Expiratory Flow Rate
  • Clinical use: Assessment of patients with asthma.
  • Patient determines “personal best” PEFR when most healthy, between asthma attacks.
  • PEFR often precedes symptoms.
  • Guide for responsiveness to meds, worsening of episodes, when to get help, etc.
diffusion capacity
Diffusion Capacity
  • Tests gas exchange across the alveolar-capillary membrane.
  • Per minute transfer of gas- Carbon Monoxide measured from alveoli to blood; DLCO.
  • Decreased if thickened alveolar capillary membrane (pulmonary fibrosis, ARDS), or following loss of surface area of the alveoli.
  • Most useful and decreased in interstitial lung disease (lecture to follow).
  • Normal mean is 25-30 mL/min/mmHg.
application of pft s
Application of PFT’s
  • Obstructive disease: asthma, COPD, bronchiectasis.
  • Pattern: FVC normal or decreased mildly.FEV1 decreased; reduction reflects severity.
  • FEV1/FVC decreased- reflects severity.
  • Response to bronchodilator indicates reversible component.
application of pft s1
Application of PFT’s
  • Restrictive disease: pulmonary fibrosis, sarcoidosis, kyphoscoliosis, neuromuscular disease, others.
  • Pattern: FVC decreased, often markedly.FEV1 decreased, often markedly.
  • FEV1/FVC normal or increased.
  • No response to bronchodilator.
problem solving
Problem Solving

22 y.o male with cough, SOB, and wheezing.

  • FVC – 3.63L (pred), 3.23L (meas), 89% pred
  • FEV1- 3.24L (pred), 2.24L (meas), 69% pred
  • FEV1/FVC 69% (meas)Post bronchodilator:
  • FVC- 3.23L
  • FEV1- 2.70L (meas) 83% pred
  • FEV1/FVC 84% (meas)
  • Interpretation: mild obstructive airways disease with post bronchodilator reversibility.
  • Diagnosis: Asthma
problem solving1
Problem Solving
  • 45 y.o black man with progressive shortness of breath.
  • FVC- 3.05L (pred), 0.81L (meas), 22% predicted
  • FEV1- 2.9L (pred) 0.69L (meas), 24% predicted
  • FEV1/FVC 97% (meas)
  • No change post bronchodilator
  • Interpretation: Severe restrictive disease; no evidence of airway obstruction.
  • Diagnosis: Sarcoidosis
pulse oximetry
Pulse Oximetry
  • Measures per cent oxygenation of hemoglobin (oxyhemoglobin).
  • Non-invasive; measures absorption of light passing through tissue, then calculates O2 saturation of arterial blood.
  • Measured via electrodes placed on skin- fingertips, ear lobes.
  • Normal = 97%
arterial blood gas measurement
Arterial Blood Gas Measurement
  • Requires arterial puncture
  • pH of arterial blood
  • PO2: partial pressure of oxygen (mmHg)
  • PCO2: partial pressure of carbon dioxide (mmHg)
  • HCO3: calculated- bicarbonate; proportional to dissolved CO2 in blood.
ad