Figures
- Fig. 1—
Spirometry standardisation steps.
- Fig. 2—
Expanded version of the early part of a subject's volume–time spirogram, illustrating back extrapolation through the steepest part of the curve, where flow is peak expiratory flow (PEF), to determine the new “time zero”. Forced vital capacity (FVC) = 4.291 L; back extrapolated volume (EV) = 0.123 L (2.9% FVC). -----: back extrapolation line through PEF.
- Fig. 3—
Flow chart outlining how acceptability and reapeatability criteria are to be applied. FVC: forced vital capacity; FEV1: forced expiratory volume in one second.
- Fig. 4—
Flow–volume loop of a normal subject.
- Fig. 5—
Flow–volume loop of a normal subject with end expiratory curvilinearity, which can be seen with ageing.
- Fig. 6—
Moderate airflow limitation in a subject with asthma.
- Fig. 7—
Severe airflow limitation in a subject with chronic obstructive pulmonary disease.
- Fig. 8—
Variable intra-thoracic upper airway obstruction.
- Fig. 9—
Variable extra-thoracic upper airway obstruction.
- Fig. 10—
Fixed upper airway obstruction shown by three manoeuvres.
- Fig. 11—
Tracing of tidal breathing followed by an expiratory manoeuvre to residual volume (RV), followed by a full inspiration to total lung capacity (TLC) to record inspiratory vital capacity (IVC) and inspiratory capacity (IC). FRC: functional residual capacity; ERV: expiratory reserve volume.
- Fig. 12—
Tracing of tidal breathing followed by an inspiratory manoeuvre to total lung capacity (TLC) to record inspiratory capacity (IC), followed by a full expiration to residual volume (RV) to record expiratory reserve volume (EVC). FRC: functional residual capacity.
Tables
- Table. 1—
Indications for spirometry
Diagnostic To evaluate symptoms, signs or abnormal laboratory tests To measure the effect of disease on pulmonary function To screen individuals at risk of having pulmonary disease To assess pre-operative risk To assess prognosis To assess health status before beginning strenuous physical activity programmes Monitoring To assess therapeutic intervention To describe the course of diseases that affect lung function To monitor people exposed to injurious agents To monitor for adverse reactions to drugs with known pulmonary toxicity Disability/impairment evaluations To assess patients as part of a rehabilitation programme To assess risks as part of an insurance evaluation To assess individuals for legal reasons Public health Epidemiological surveys Derivation of reference equations Clinical research - Table. 2—
Recommended minimum scale factors for time, volume and flow on graphical output
Instrument display Hardcopy graphical output Parameter Resolution required Scale factor Resolution required Scale factor Volume# 0.050 L 5 mm·L−1 0.025 L 10 mm·L−1 Flow# 0.200 L·s−1 2.5 mm·L−1·s−1 0.100 L·s−1 5 mm·L−1·s−1 Time 0.2 s 10 mm·s−1 0.2 s 20 mm·s−1 #: the correct aspect ratio for a flow versus volume display is two units of flow per one unit of volume.
- Table. 3—
Summary of equipment quality control
Test Minimum interval Action Volume Daily Calibration check with a 3-L syringe Leak Daily 3 cmH2O (0.3 kPa) constant pressure for 1 min Volume linearity Quarterly 1-L increments with a calibrating syringe measured over entire volume range Flow linearity Weekly Test at least three different flow ranges Time Quarterly Mechanical recorder check with stopwatch Software New versions Log installation date and perform test using “known” subject - Table. 4—
Procedures for recording forced vital capacity
Check the spirometer calibration Explain the test Prepare the subject Ask about smoking, recent illness, medication use, etc. Measure weight and height without shoes Wash hands Instruct and demonstrate the test to the subject, to include Correct posture with head slightly elevated Inhale rapidly and completely Position of the mouthpiece (open circuit) Exhale with maximal force Perform manoeuvre (closed circuit method) Have subject assume the correct posture Attach nose clip, place mouthpiece in mouth and close lips around the mouthpiece Inhale completely and rapidly with a pause of <1 s at TLC Exhale maximally until no more air can be expelled while maintaining an upright posture Repeat instructions as necessary, coaching vigorously Repeat for a minimum of three manoeuvres; no more than eight are usually required Check test repeatability and perform more manoeuvres as necessary Perform manoeuvre (open circuit method) Have subject assume the correct posture Attach nose clip Inhale completely and rapidly with a pause of <1 s at TLC Place mouthpiece in mouth and close lips around the mouthpiece Exhale maximally until no more air can be expelled while maintaining an upright posture Repeat instructions as necessary, coaching vigorously Repeat for a minimum of three manoeuvres; no more than eight are usually required Check test repeatability and perform more manoeuvres as necessary TLC: total lung capacity.
- Table. 5—
Summary of within- and between-manoeuvre acceptability criteria
Within-manoeuvre criteria Individual spirograms are “acceptable” if They are free from artefacts 3 Cough during the first second of exhalation Glottis closure that influences the measurement Early termination or cut-off Effort that is not maximal throughout Leak Obstructed mouthpiece They have good starts Extrapolated volume <5% of FVC or 0.15 L, whichever is greater They show satisfactory exhalation Duration of ≥6 s (3 s for children) or a plateau in the volume–time curve or If the subject cannot or should not continue to exhale Between-manoeuvre criteria After three acceptable spirograms have been obtained, apply the following tests The two largest values of FVC must be within 0.150 L of each other The two largest values of FEV1 must be within 0.150 L of each other If both of these criteria are met, the test session may be concluded If both of these criteria are not met, continue testing until Both of the criteria are met with analysis of additional acceptable spirograms or A total of eight tests have been performed (optional) or The patient/subject cannot or should not continue Save, as a minimum, the three satisfactory manoeuvres FVC: forced vital capacity; FEV1: forced expiratory volume in one second.
- Table. 6—
Range and accuracy recommendations specified for forced expiratory manoeuvres
Test Range/accuracy (BTPS) Flow range L·s−1 Time s Resistance and back pressure Test signal VC 0.5–8 L, ±3% of reading or ±0.050 L, whichever is greater 0–14 30 3-L Calibration syringe FVC 0.5–8 L, ±3% of reading or ±0.050 L, whichever is greater 0–14 15 <1.5 cmH2O·L−1·s−1 (0.15 kPa·L−1·s−1) 24 ATS waveforms, 3-L Cal Syringe FEV1 0.5–8 L, ±3% of reading or ±0.050 L, whichever is greater 0–14 1 <1.5 cmH2O·L−1·s−1 (0.15 kPa·L−1·s−1) 24 ATS waveforms Time zero The time point from which all FEVt measurements are taken Back extrapolation PEF Accuracy: ±10% of reading or ±0.30 L·s−1 (20 L·min−1), whichever is greater; repeatability: ±5% of reading or ±0.15 L·s−1 (10 L·min−1), whichever is greater 0–14 Mean resistance at 200, 400, 600 L·min−1 (3.3, 6.7, 10 L·s−1) must be <2.5 cmH2O·L−1·s−1 (0.25 kPa·L−1·s−1) 26 ATS flow waveforms Instantaneous flows (except PEF) Accuracy: ±5% of reading or ±0.200 L·s−1, whichever is greater 0–14 <1.5 cmH2O·L−1·s−1 (0.15 kPa·L−1·s−1) Data from manufacturers FEF25–75% 7.0 L·s−1, ±5% of reading or ±0.200 L·s−1, whichever is greater ±14 15 Same as FEV1 24 ATS waveforms MVV 250 L·min−1 at VT of 2 L within ±10% of reading or ±15 L·min−1, whichever is greater ±14 (±3%) 12–15 <1.5 cmH2O·L−1·s−1 (0.15 kPa·L−1·s−1) Sine wave pump BTPS: body temperature and ambient pressure saturated with water vapour; VC: vital capacity; FVC: forced vital capacity; ATS: American Thoracic Society; FEV1: forced expiratory volume in one second; FEVt: forced expiratory volume in t seconds; PEF: peak expiratory flow; FEF25–75%: mean forced expiratory flow between 25% and 75% of FVC; MVV: maximum voluntary ventilation; VT: tidal volume.
- Table. 7—
List of abbreviations and meanings
ATPD Ambient temperature, ambient pressure, and dry ATPS Ambient temperature and pressure saturated with water vapour BTPS Body temperature (i.e. 37°C), ambient pressure, saturated with water vapour C Centigrade CFC Chlorofluorocarbons cm Centimetres COHb Carboxyhaemoglobin DL,CO Diffusing capacity for the lungs measured using carbon monoxide, also known as transfer factor DL,CO/VA Diffusing capacity for carbon monoxide per unit of alveolar volume, also known as KCO DM Membrane-diffusing capacity DT Dwell time of flow >90% of PEF EFL Expiratory flow limitation ERV Expiratory reserve volume EV Back extrapolated volume EVC Expiratory vital capacity FA,X Fraction of gas X in the alveolar gas FA,X,t Alveolar fraction of gas X at time t FEF25-75% Mean forced expiratory flow between 25% and 75% of FVC FEFX% Instantaneous forced expiratory flow when X% of the FVC has been expired FEV1 Forced expiratory volume in one second FEVt Forced expiratory volume in t seconds FE,X Fraction of expired gas X FIFX% Instantaneous forced inspiratory flow at the point where X% of the FVC has been inspired FI,X Fraction of inspired gas X FIVC Forced inspiratory vital capacity FRC Functional residual capacity FVC Forced vital capacity H2O Water Hb Haemoglobin Hg Mercury Hz Hertz; cycles per second IC Inspiratory capacity IVC Inspiratory vital capacity KCO Transfer coefficient of the lung (i.e.DL,CO/VA) kg Kilograms kPa Kilopascals L Litres L·min−1 Litres per minute L·s−1 Litres per second lb Pounds weight MEFX% Maximal instantaneous forced expiratory flow where X% of the FVC remains to be expired MFVL Maximum flow–volume loop mg Milligrams MIF Maximal inspiratory flow mL Millilitres mm Millimetres MMEF Maximum mid-expiratory flow ms Milliseconds MVV Maximum voluntary ventilation PA,O2 Alveolar oxygen partial pressure PB Barometric pressure PEF Peak expiratory flow PH2O Water vapour partial pressure PI,O2 Inspired oxygen partial pressure θ (theta) Specific uptake of CO by the blood RT Rise time from 10% to 90% of PEF RV Residual volume s Seconds STPD Standard temperature (273 K, 0°C), pressure (101.3 kPa, 760 mmHg) and dry TB Tuberculosis TGV (or VTG) Thoracic gas volume tI Time taken for inspiration TLC Total lung capacity Tr Tracer gas ttot Total time of respiratory cycle VA Alveolar volume VA,eff Effective alveolar volume VC Vital capacity Vc Pulmonary capillary blood volume VD Dead space volume VI Inspired volume VS Volume of the expired sample gas μg Micrograms - Table. 8—
List of parameters#
ID (patient identification) Patient name Data type (SP followed by E = expiratory or I = Inspiratory, followed by S = single or B = best curve) Barometric pressure (mmHg) Temperature (°C) used in BTPS calculation Relative humidity (%) FVC quality attribute (A, B, C, D or F) FEV1 quality attribute (A, B, C, D or F) Effort attribute (A, B, C, D or F) Interpretation code (see ATS interpretation scheme) Deleted manoeuvre (Y or N) Acceptable manoeuvre (Y or N) Technician quality control code (A, B, C, D or F) Computer quality code (A, B, C, D or F) Plateau achieved (Y or N) Review (N or R for “needs review” or “was reviewed”) Date of review (DD/MM/YYYY) Reviewer initials BTPS factor (x.xxx) Spirometer manufacturer Spirometer model Spirometer serial number Spirometer type Testing facility name City State/region Zip/post code Country E-mail Phone number Calibration date (DD/MM/YYYY) Calibration time (HH:MM) Calibration result (P or F for “passed” or “failed”) Date (DD/MM/YYYY) Time (HH:MM) Technician ID (technician identification code or initials) Manoeuvre number Age (integer years) Height (cm) Weight (kg) Sex (M or F) Race (2-character race code) Date of birth (DD/MM/YYYY) Reference values source (first author surname and date of publication, e.g. “Knudson 1983”) Reference values correction factor (x.xx, 1.00 for no correction) Testing position (standing, sitting or supine) Test type (pre-, post-, bronchodilator, methacholine concentration or dose) FVC (mL) Extrapolated volume (mL) FEV1 (mL) FEV6 (mL) PEF (mL·s−1) FEF25–75% (mL·s−1) VC (mL) Forced expiratory time (s) Time to PEF (ms) Predicted FVC (mL) Predicted FEV1 (mL) Predicted FEV6 (mL) Predicted FEV1/FVC% (xxx.x%) Predicted FEV1/FEV6% (xxx.x%) Comments text Original sampling interval (ms) Blank 1 or FEF25% Blank 2 or FEF50% Blank 3 or FEF75% Blank 4 or FEF90% Blank 5 Blank 6 Blank 7 Blank 8 Blank 9 Blank 10 Number of data points Flow data points (mL·s−1; variable number contained in number of data points) Carriage return Line feed #: All text type variables should be enclosed with double quotes (“) to prevent confusion with control or data separator type characteristics.
