Spirometry in Primary Care Dr Max Matonhodze FRCP (London) M A Med Ed (Keele)

Objectives Need for performing spirometry Types of spirometers Spirometric indices Obstructive spirometry and severity scale Practical tips Quality control Illustrative examples

COPD NICE guidance 2010 The presence of airflow obstruction should be confirmed by performing post-bronchodilator spirometry. All health professionals involved in the care of people with COPD should have access to spirometry and be competent in the interpretation of the results.

WHY? 3 million people are estimated to have COPD in UK are diagnosed 2 million are living with undiagnosed COPD About 70% of COPD remain undiagnosed

Spirometry Spirometry is the gold standard for COPD diagnosis Widespread uptake has been limited by: Concerns over technical performance of operators Difficulty with interpretation of results Lack of approved local training courses Lack of evidence showing clear benefit when spirometry is incorporated into management

What is Spirometry? Spirometry is a method of assessing lung function by measuring the total volume of air the patient can expel from the lungs after a maximal inhalation.

Why Perform Spirometry? Measure airflow obstruction to help make a definitive diagnosis of COPD Confirm presence of airway obstruction Assess severity of airflow obstruction in COPD Detect airflow obstruction in smokers who may have few or no symptoms Monitor disease progression in COPD Assess one aspect of response to therapy Assess prognosis (FEV 1 ) in COPD Perform pre-operative assessment

Types of Spirometers Bellows spirometers: M easure volume; mainly in lung function units Electronic desk top spirometers: Measure flow and volume with real time display Small hand-held spirometers: Inexpensive and quick to use but no print out

Volume Measuring Spirometer

Flow Measuring Spirometer

Desktop Electronic Spirometers

Small Hand-held Spirometers

Standard Spirometric Indicies FEV 1 - Forced expiratory volume in one second: The volume of air expired in the first second of the blow FVC - Forced vital capacity: The total volume of air that can be forcibly exhaled in one breath FEV 1 /FVC ratio: The fraction of air exhaled in the first second relative to the total volume exhaled

Additional Spirometric Indicies VC - Vital capacity: A volume of a full breath exhaled in the patient’s own time and not forced. Often slightly greater than the FVC, particularly in COPD FEV 6 – Forced expired volume in six seconds: Often approximates the FVC. Easier to perform in older and COPD patients but role in COPD diagnosis remains under investigation MEFR – Mid-expiratory flow rates: Derived from the mid portion of the flow volume curve but is not useful for COPD diagnosis

Lung Volume Terminology Total lung capacity Inspiratory reserve volume Tidal volume Expiratory reserve volume Residual volume Inspiratory capacity

Spirogram Patterns Normal Obstructive Restrictive Mixed Obstructive and Restrictive

Spirometry Predicted Normal Values

Predicted Normal Values Affected by: Age Height Sex Ethnic Origin

Criteria for Normal Post-bronchodilator Spirometry FEV 1 : % predicted > 80% FVC: % predicted > 80% FEV 1 /FVC: > , depending on age

Normal Trace Showing FEV 1 and FVC Volume, liters Time, sec FEV 1 = 4L FVC = 5L FEV 1 /FVC = 0.8 FVC

SPIROMETRY OBSTRUCTIVE DISEASE

Spirometry: Obstructive Disease Time, seconds Volume, liters Normal FEV 1 = 1.8L FVC = 3.2L FEV 1 /FVC = 0.56 Obstructive

Diseases Associated With Airflow Obstruction COPD Asthma Bronchiectasis Cystic Fibrosis Post-tuberculosis Lung cancer (greater risk in COPD) Obliterative Bronchiolitis

Spirometric Diagnosis of COPD COPD is confirmed by post–bronchodilator FEV 1 /FVC < 0.7 Plus FEV 1 %pred >80%= Mild FEV 1 %Pred 50-79% =moderate FEV 1 % Pred 30-49% =Severe FEV 1 %pred <30%= very severe

SPIROMETRY RESTRICTIVE DISEASE

Criteria: Restrictive Disease FEV 1: normal or mildly reduced FVC: < 80% predicted FEV 1 /FVC: > 0.7

Spirometry: Restrictive Disease Volume, liters Time, seconds Restrictive Normal FEV 1 = 1.9L FVC = 2.0L FEV 1 /FVC = 0.95

Diseases Associated with a Restrictive Defect Pulmonary Fibrosing lung diseases Pneumoconioses Pulmonary edema Parenchymal lung tumors Lobectomy or pneumonectomy Extrapulmonary Thoracic cage deformity Obesity Pregnancy Neuromuscular disorders Fibrothorax

Mixed Obstructive/Restrictive FEV 1 : < 80% predicted FVC: < 80% predicted FEV 1 /FVC: < 0.7

SPIROMETRY Flow Volume

Flow Volume Curve Standard on most desk-top spirometers Adds more information than volume time curve Less understood but not too difficult to interpret Better at demonstrating mild airflow obstruction

Flow Volume Curve Expiratory flow rate L/sec FVC Maximum expiratory flow (PEF) Inspiratory flow rate L/sec RV TLC Volume (L)

Flow Volume Curve Patterns Obstructive and Restrictive ObstructiveSevere obstructiveRestrictive Volume (L) Expiratory flow rate Volume (L) Steeple pattern, reduced peak flow, rapid fall off Normal shape, normal peak flow, reduced volume Reduced peak flow, scooped out mid- curve

Spirometry: Abnormal Patterns ObstructiveRestrictiveMixed Time Volume Slow rise, reduced volume expired; prolonged time to full expiration Fast rise to plateau at reduced maximum volume Slow rise to reduced maximum volume; measure static lung volumes and full PFT’s to confirm

PRACTICAL SESSION Performing Spirometry

Spirometry Training Training is essential for operators to learn correct performance and interpretation of results Training for competent performance of spirometry requires a minimum of 3 hours Acquiring good spirometry performance and interpretation skills requires practice, evaluation, and review Spirometry performance (who, when and where) should be adapted to local needs and resources Training for spirometry should be evaluated

Obtaining Predicted Values Independent of the type of spirometer Choose values that best represent the tested population Check for appropriateness if built into the spirometer Optimally, subjects should rest 10 minutes before performing spirometry

Performing Spirometry - Preparation 1.Explain the purpose of the test and demonstrate the procedure 2.Record the patient’s age, height and gender and enter on the spirometer 3.Note when bronchodilator was last used 4.Have the patient sitting comfortably 5.Loosen any tight clothing 6.Empty the bladder beforehand if needed

Performing Spirometry Breath in until the lungs are full Hold the breath and seal the lips tightly around a clean mouthpiece Blast the air out as forcibly and fast as possible. Provide lots of encouragement! Continue blowing until the lungs feel empty

Performing Spirometry Watch the patient during the blow to assure the lips are sealed around the mouthpiece Check to determine if an adequate trace has been achieved Repeat the procedure at least twice more until ideally 3 readings within 100ml or 5% of each other are obtained

Reproducibility - Quality of Results Volume, liters Time, seconds Three times FVC within 5% or 0.15 litre (150 ml)

Spirometry - Possible Side Effects Feeling light-headed Headache Getting red in the face Fainting: reduced venous return or vasovagal attack (reflex) Transient urinary incontinence Spirometry should be avoided after recent heart attack or stroke

Spirometry - Quality Control Most common cause of inconsistent readings is poor patient technique Sub-optimal inspiration Sub-maximal expiratory effort Delay in forced expiration Shortened expiratory time Air leak around the mouthpiece Subjects must be observed and encouraged throughout the procedure

Spirometry – Common Problems Inadequate or incomplete blow Lack of blast effort during exhalation Slow start to maximal effort Lips not sealed around mouthpiece Coughing during the blow Extra breath during the blow Glottic closure or obstruction of mouthpiece by tongue or teeth Poor posture – leaning forwards

Equipment Maintenance Most spirometers need regular calibration to check accuracy Calibration is normally performed with a 3 litre syringe Some electronic spirometers do not require daily/weekly calibration Good equipment cleanliness and anti-infection control are important; check instruction manual Spirometers should be regularly serviced; check manufacturer’s recommendations

Troubleshooting Examples - Unacceptable Traces

Unacceptable Trace - Poor Effort Volume, liters Time, seconds May be accompanied by a slow start Inadequate sustaining of effort Variable expiratory effort Normal

Unacceptable Trace – Stop Early Volume, liters Time, seconds Normal

Unacceptable Trace – Slow Start Volume, liters Time, seconds

Unacceptable Trace - Coughing Volume, liters Time, seconds Normal

Unacceptable Trace – Extra Breath Volume, liters Time, seconds Normal

Spirometry Mrs PZ 47 yrs FEV-1 = 0.8L (35% of pred) FVC = 2.4L (85% of pred) FEV-1/FVC Ratio = 30%

Spirometry Answer:

Spirometry Mr PY 83 FEV-1 =0.6L (28%pred) FVC = 1.9 L (81% pred) FEV-1/FVC ratio =31.5%

Spirometry Answer:

Spirometry Mr BY 63 FEV-1 = 1.6 L (63% pred FVC = 2.1 L (67% pred) FEV-1/FVC ratio = 76% Mr BY 63 FEV-1 = 1.6 L (63% pred FVC = 2.1 L (67% pred) FEV-1/FVC ratio = 76%

Spirometry Answer-

Spirometry Mrs TZ 56 FEV-1 =1.1L (41% pred) FVC = 2.3 L (63%pred) FEV-1/FVC ratio =48%

Spirometry Answer?

Some Spirometry Resources Global Initiative for Chronic Obstructive Lung Disease (GOLD) - Spirometry in Practice - ATS-ERS Taskforce: Standardization of Spirometry. ERJ 2005;29: National Asthma Council: Spirometry Handbook