Lung Function Tests Sema Umut Lung Factors Affecting

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Lung Function Tests Sema Umut

Lung Function Tests Sema Umut

Lung Factors Affecting Function Mechanical properties Resistive elements

Lung Factors Affecting Function Mechanical properties Resistive elements

Mechanical Properties Compliance Describes the stiffness of the lungs Change in volume over the

Mechanical Properties Compliance Describes the stiffness of the lungs Change in volume over the change in pressure Elastic recoil The tendency of the lung to return to it’s resting state

Resistive Properties Determined by airway caliber Affected by Lung volume Bronchial smooth muscles Airway

Resistive Properties Determined by airway caliber Affected by Lung volume Bronchial smooth muscles Airway collapsibility

A TEST SHOULD BE Acceptabile, easy Noninvasive Cost effective Informative Reproducible

A TEST SHOULD BE Acceptabile, easy Noninvasive Cost effective Informative Reproducible

Spirometry Acceptabile, easy Noninvasive Cost effective Inexpensive Informative Reproducible

Spirometry Acceptabile, easy Noninvasive Cost effective Inexpensive Informative Reproducible

Spirometry It is the most commonly used lung function screening study It should be

Spirometry It is the most commonly used lung function screening study It should be the clinician's first option

When can spirometry help us? - Diagnosing disease - Monitoring disease - Prognosis -

When can spirometry help us? - Diagnosing disease - Monitoring disease - Prognosis - Directing therapy

Indications for Spirometry Diagnostic To evaluate symptoms, signs, or abnormal laboratory tests Dyspnea Wheezing

Indications for Spirometry Diagnostic To evaluate symptoms, signs, or abnormal laboratory tests Dyspnea Wheezing Cough Abnormal breath sounds Overinflation Expiratory slowing Cyanosis

Abnormal laboratory tests Hypoxemia Hypercapnia Polycythemia Abnormal chest radiographs

Abnormal laboratory tests Hypoxemia Hypercapnia Polycythemia Abnormal chest radiographs

To screen individuals at risk of having pulmonary diseases Smokers Individuals in occupations with

To screen individuals at risk of having pulmonary diseases Smokers Individuals in occupations with exposures to injurious substances

Indications for Spirometry To assess preoperative risk To assess health status before physical activity

Indications for Spirometry To assess preoperative risk To assess health status before physical activity programs To evaluate therapy

Disability/Impairment Evaluations To assess individuals for legal reasons

Disability/Impairment Evaluations To assess individuals for legal reasons

Prognosis Survival predictor of general population Copenhagen City Heart Study 13, 900 subjects for

Prognosis Survival predictor of general population Copenhagen City Heart Study 13, 900 subjects for 25 yrs Lange P. J Clin Epidemiol 1990; 43: 867 -873. Cox proportional hazards FEV 1/ht 2 best index Framingham study

Spirometry Requirements 1. Good equipment 2. Good technicians (efor dependent) 3. Good clinicians -

Spirometry Requirements 1. Good equipment 2. Good technicians (efor dependent) 3. Good clinicians - correct indication - correct use / presentation of the data - correct decision making

Pulmonary Function Testing relates Age : Smaller lung volumes as we age Gender :

Pulmonary Function Testing relates Age : Smaller lung volumes as we age Gender : The lung volumes of males are larger than females Height Race

Perform manoeuvre Attach nose clip, place mouthpiece in mouth Inhale completely and rapidly Exhale

Perform manoeuvre Attach nose clip, place mouthpiece in mouth Inhale completely and rapidly Exhale maximally until no more air can be expelled Repeat for a minimum of 3 manoeuvres

Forced Vital Capacity FVC Total volume of air expired forcefully after a full inspiration

Forced Vital Capacity FVC Total volume of air expired forcefully after a full inspiration Patients with restrictive lung disease have a decreased vital capacity

Slow Vital Capacity (SVC) This is the total volume of air expired slowly after

Slow Vital Capacity (SVC) This is the total volume of air expired slowly after a full inspiration If the SVC is greater than FVC, it indicates the presence of obstructive disease

Forced Expiratory Volume in 1 Second FEV 1 Volume of air expired in the

Forced Expiratory Volume in 1 Second FEV 1 Volume of air expired in the first second during maximal expiratory effort

FEV 1/FVC Percentage of the forced vital capacity which is expired in the first

FEV 1/FVC Percentage of the forced vital capacity which is expired in the first second of maximal expiration to forced vital capacity In health the FEV 1/FVC is usually around 80% Decrease in FEV 1/FVC means obstruction

Tidal volume TV The volume of air moved during normal quiet breathing (about 0.

Tidal volume TV The volume of air moved during normal quiet breathing (about 0. 5 L)

RESIDUEL VOLUME (RV) The volume of air remaining in the lungs after a forceful

RESIDUEL VOLUME (RV) The volume of air remaining in the lungs after a forceful expiration (about 1. 0 L).

FUNCTIONAL RESIDUEL CAPACITY(FRC) The amount of air remaining in the lungs after a normal

FUNCTIONAL RESIDUEL CAPACITY(FRC) The amount of air remaining in the lungs after a normal quiet expiration

TOTAL LUNG CAPACITY (TLC) It is the volume of air in the lungs when

TOTAL LUNG CAPACITY (TLC) It is the volume of air in the lungs when the person has taken a full inspiration TLC = RV + VC

TLC, RV, FRC Can not be measured by spirometry Helium dilution Nitrogenmetry Body plethysmography

TLC, RV, FRC Can not be measured by spirometry Helium dilution Nitrogenmetry Body plethysmography

INTERPRETATION OF SPIROMETRY Compare the measured values of the patient with normal values derived

INTERPRETATION OF SPIROMETRY Compare the measured values of the patient with normal values derived from population studies The percent predicted normal is used to define normal and abnormal and to grade the severity of the abnormality

Categories of Disease Obstructive Restrictive Mixed

Categories of Disease Obstructive Restrictive Mixed

Spirogram measures two components - air flow and volume If flow is reduced, the

Spirogram measures two components - air flow and volume If flow is reduced, the defect is obstructive If volume is reduced the defect is restrictive

Interpretation FVC and FEV 1 are normal – NORMAL FVC is low but FEV

Interpretation FVC and FEV 1 are normal – NORMAL FVC is low but FEV 1/FVC is >80 RESTRICTIVE FEV 1/FVC < 70% OBSTRUCTIVE

Spirometry Obstruction (FEVı /FVC) < %70

Spirometry Obstruction (FEVı /FVC) < %70

Obstructive Lung Diseases Asthma Chronic obstructive pulmonary disease

Obstructive Lung Diseases Asthma Chronic obstructive pulmonary disease

COPD -COPD is characterized by airflow limitation that is not fully reversible -The airflow

COPD -COPD is characterized by airflow limitation that is not fully reversible -The airflow limitation is usually progressive and associated with an abnormal inflammatory response of the lung to noxious particles or gases

Diagnosis of COPD SYMPTOMS cough sputum shortness of breath EXPOSURE TO RISK FACTORS tobacco

Diagnosis of COPD SYMPTOMS cough sputum shortness of breath EXPOSURE TO RISK FACTORS tobacco occupation indoor/outdoor pollution è SPIROMETRY

Asthma is a chronic inflammatory disease of the airways Inflammation causes the airways to

Asthma is a chronic inflammatory disease of the airways Inflammation causes the airways to narrow periodically This produces wheezing and breathlessness Obstruction to air flow is reversible

Bronchodilator Test Evaluates how responsive the patient is to a bronchodilator medication Spirometry is

Bronchodilator Test Evaluates how responsive the patient is to a bronchodilator medication Spirometry is repeated about 15 minutes after giving a bronchodilator (400 mg salbutamol)

WHY TEST FOR REVERSIBILITY? To determine best function To follow rate of change in

WHY TEST FOR REVERSIBILITY? To determine best function To follow rate of change in PFTs over time To exclude asthma To determine response to therapy

REVERSIBILITY Increase of 200 ml or 12 -15% of the baseline FEV 1 shows

REVERSIBILITY Increase of 200 ml or 12 -15% of the baseline FEV 1 shows REVERSIBLE OBSTRUCTION 40 Both drugs combined 30 20 10 0 0 2 4 6 8

Restriction means a decrease in lung volumes

Restriction means a decrease in lung volumes

Extrinsic Restrictive Lung Disorders. Neuromuscular Disorders. Scoliosis, Kyphosis. Rib fractures. Pleural Effusion. Pregnancy. Gross

Extrinsic Restrictive Lung Disorders. Neuromuscular Disorders. Scoliosis, Kyphosis. Rib fractures. Pleural Effusion. Pregnancy. Gross Obesity. Tumors. Ascites

Intrinsic Restrictive Lung Disorders Pnuemonectomy Pneumonia Lung tumors Interstitial lung diseases Sarcoidosis Lung oedema

Intrinsic Restrictive Lung Disorders Pnuemonectomy Pneumonia Lung tumors Interstitial lung diseases Sarcoidosis Lung oedema

Flow – Volume Loop is a measure of how much air can be inspired

Flow – Volume Loop is a measure of how much air can be inspired and expired from the lungs It is a flow rate measurement

Restrictive Lung Disease Characterized by diminished lung volume Decreased TLC, FVC Normal FEV 1/FVC

Restrictive Lung Disease Characterized by diminished lung volume Decreased TLC, FVC Normal FEV 1/FVC ratio

Large Airway Obstruction can be detected by Flow – Volume Loop Characterized by a

Large Airway Obstruction can be detected by Flow – Volume Loop Characterized by a truncated inspiratory or expiratory loop

Extra-thoracic Upper Airway Obstruction

Extra-thoracic Upper Airway Obstruction

Peak Expiratory Flow Rate PEFR The maximum flow rate during the forced vital capacity

Peak Expiratory Flow Rate PEFR The maximum flow rate during the forced vital capacity maneuver Useful to monitor asthma

Measuring PEF must be achieved as rapidly as possible and at a high lung

Measuring PEF must be achieved as rapidly as possible and at a high lung volume as possible The subject must be encouraged to blow as vigorously as possible

When is PEF useful? PEF can be very useful in diagnosing occupational asthma

When is PEF useful? PEF can be very useful in diagnosing occupational asthma

ARTERIAL BLOOD GASES INDICATION Oxygenation Ventilation Acid-Base Status

ARTERIAL BLOOD GASES INDICATION Oxygenation Ventilation Acid-Base Status

ARTERIAL BLOOD GASES Blood gases is a measurement of how much oxygen and carbon

ARTERIAL BLOOD GASES Blood gases is a measurement of how much oxygen and carbon dioxide is in the blood Determines the acidity (p. H) of the blood

ARTERIAL BLOOD GASES Blood is taken from an artery The blood may be collected

ARTERIAL BLOOD GASES Blood is taken from an artery The blood may be collected from the radial artery, the femoral artery , or the brachial artery

ARTERIAL BLOOD GASES After the blood is taken, pressure is applied to the site

ARTERIAL BLOOD GASES After the blood is taken, pressure is applied to the site for a few minutes to stop the bleeding The sample must be quickly sent to a laboratory

Blood Gas Report p. H Pa. CO 2 (mm Hg) Pa. O 2 (mm

Blood Gas Report p. H Pa. CO 2 (mm Hg) Pa. O 2 (mm Hg) HCO 3 - (mmol/L) B. E. (mmol/L) O 2 saturation 7. 4 40 110 - 0. 5(age) 24 0 >90%

Causes of a low Pa. O 2 V/Q mismatch Dead space ventilation Shunt Diffusion

Causes of a low Pa. O 2 V/Q mismatch Dead space ventilation Shunt Diffusion Impairment Alveolar Hypoventilation Altitude

Alveolar Hypoventilation Reduced Respiratory Drive Pump failure

Alveolar Hypoventilation Reduced Respiratory Drive Pump failure

ANALYSIS OF VENTILATON Hypercapnea > 45 mm Hg Hypoventilation Respiratory Acidosis Hypocapnea < 35

ANALYSIS OF VENTILATON Hypercapnea > 45 mm Hg Hypoventilation Respiratory Acidosis Hypocapnea < 35 mm Hg Hyperventilation Respiratory Alkalosis

Respiratory alkalosis Low levels of carbon dioxide in the blood due to alveolar hypervetilation

Respiratory alkalosis Low levels of carbon dioxide in the blood due to alveolar hypervetilation (breathing excessively)

Respiratory acidosis The kidneys and lungs maintain the body's acid/base (p. H) balance Respiratory

Respiratory acidosis The kidneys and lungs maintain the body's acid/base (p. H) balance Respiratory acidosis develops when carbon dioxide is elevated Primarily caused by alveoler hypoventilation ( decreased breathing)

Pitfalls Venous Sample _Pa. O 2 = 40, Pa. CO 2 = 45 Free

Pitfalls Venous Sample _Pa. O 2 = 40, Pa. CO 2 = 45 Free flow into syringe Air-bubble in syringe Falsely elevated Pa. O 2 Arterial blood sample should be transported on ice under anaerobic conditions

Spirometry is essential in respiratory evaluation as tension arterial measurement is essential in cardiovascular

Spirometry is essential in respiratory evaluation as tension arterial measurement is essential in cardiovascular evaluation