General considerations for lung function testing

1 SERIES ATS/ERS TASK FORCE: STANDARDISATION OF LUNGFUNCTION testing Edited by V. Brusasco, R. Crapo and G. ViegiNumber 1 in this SeriesGeneral considerations for lung Miller, R. Crapo, J. Hankinson, V. Brusasco, F. Burgos, R. Casaburi,A. Coates, P. Enright, van der Grinten, P. Gustafsson, R. Jensen, Johnson, N. MacIntyre, R. McKay, D. Navajas, Pedersen,R. Pellegrino, G. Viegi and J. 154 Patient 154 Contraindications .. 154 Position .. 154 Patient 154 Age, height and weight .. 154 Therapy .. 154 Subject preparation .. 154 Laboratory 155 Hygiene and infection 155 Transmission by direct contact .. 155 Transmission by indirect contact .. 155 Prevention .. 155 Transmission to technicians .. 155 Cross-contamination .. 156 Volume-based spirometers .. 156 Tuberculosis .. 156 Haemoptysis and oral lesions .. 156 Other known transmissible infectious diseases.

2 156 Disposable in-line filters .. 156 Equipment design .. 157 Level of infection risk.. 157 Personnel qualifications and technician s role in quality 157 Personnel qualifications .. 157 Technician s role in quality control .. 158 Reference 158 Interpretation 159 KEYWORDS:Diffusing capacity, infections, lung function measurements, lung volume measure-ments, reference values, spirometry standardisationAFFILIATIONSFor affiliations, please seeAcknowledgements sectionCORRESPONDENCEV. BrusascoInternal MedicineUniversity of Benedetto XV, 6I-16132 GenovaItalyFax: 10 3537690E-mail: 23 2005 Accepted:April 05 2005 European Respiratory JournalPrint ISSN 0903-1936 Online ISSN 1399-3003 For editorial comments see page RESPIRATORY JOURNALVOLUME 26 NUMBER 1153 Eur Respir J 2005; 26: 153 161 DOI: ERS Journals Ltd 2005cBACKGROUNDIn preparing the joint statements on lung function testing forthe American Thoracic Society (ATS) and the EuropeanRespiratory Society (ERS), it was agreed by the working partythat the format of the statements should be modified so thatthey were easier to use by both technical and clinical staff.

3 Thisstatement contains details about procedures that are commonfor many methods of lung function testing and, hence, arepresented on their own. A list of abbreviations used in all thedocuments is also included as part of this terms and abbreviations used here are based on a report oftheAmericanCollegeofChestPhysicians/AT SJ ointCommittee on Pulmonary Nomenclature [1]. The metrologydefinitions agreed by the International Standards Organization(ISO) are recommended [2] and some important terms aredefined as is the closeness of agreement between the result of ameasurement and the conventional true is the closeness of agreement between the resultsof successive measurements of the same item carried out,subject to all of the following conditions: same method, sameobserver, same instrument, same location, same condition ofuse, and repeated over a short space of time.

4 In previousdocuments, the term reproducibility was used in this context,and this represents a change towards bringing this documentin line with the is the closeness of agreement of the results ofsuccessive measurements of the same item where the individualmeasurements are carried out with changed conditions, such as:method of measurement, observer, instrument, location, condi-tions of use, and time. Thus, if a technician tests a subject severaltimes, this is looking at the repeatability of the test. If the subjectis then given a bronchodilator drug and tested again after30 min, one needs to know the reproducibility of the test inorder to make a decision on this measurement range for a recording device is the rangeover which the manufacturer indicates the device complieswith the recommendations resolution is the smallest detectable change CONSIDERATIONSC ontraindicationsPerforming lung function tests can be physically demandingfor a minority of patients.

5 It is recommended that patientsshould not be tested within 1 month of a myocardial with any of the conditions listed in table 1 are unlikelyto achieve optimal or repeatable may be performed either in the sitting or standingposition, and the position should be recorded on the report [3,4]. Sitting is preferable for safety reasons in order to avoidfalling due to syncope. The chair should have arms and bewithout wheels. If a wheelchair is used, the wheels should belocked. If the standing position is used, a chair can be placedbehind the patient/subject, so that they can be quickly andeasily moved into a sitting position if they become light-headed during the manoeuvre. Obese subjects, or those withexcessive weight at the mid-section, will frequently obtain adeeper inspiration when tested in the standing , forced expiratory volumes and flows mayimprove with the standing position in these subjects typically have equivalent values whentested sitting or standing, but, for longitudinal studies, thesame test position should be used each DETAILSAge, height and weightThe patient s age, height and weight (wearing indoor clotheswithout shoes) are recorded for use in the calculation ofreference values.

6 The age should be expressed in years. Heightand weight should be expressed with the units in use in thecountry, corresponding to the ones of the selected referenceequation. Body mass index should be calculated as kg?m-2. Theheight should be measured without shoes, with the feettogether, standing as tall as possible with the eyes level andlooking straight ahead, and using an accurate measuringdevice. For patients with a deformity of the thoracic cage, suchas kyphoscoliosis, the arm span from fingertip to fingertip canbe used as an estimate of height. Arm span should bemeasured with the subject standing against a wall with thearms stretched to attain the maximal distance between the tipsof the middle fingers. A regression equation using arm span,race, sex and age has been found to account for 87% of thevariance in standing height [5], with the standard error of theestimate for height ranging from to cm.

7 Using fixedarm-span ratios ( ) estimated thestanding height reasonably well, except at the extremes, butwas always inferior to the regression equation. Estimatingheight in this way introduces a further level of uncertaintywith regard to the predicted value of the lung function index,and the use of fixed ratios has been shown to lead tomisclassification of disease [6]. The use of knee height topredict height can also be used for handicapped people wherearm span may be difficult to measure [7, 8].TherapyThe operator should record the type and dosage of any(inhaled or oral) medication that may alter lung function andwhen the drugs were last preparationSubjects should avoid the activities listed in table 2, and theserequirements should be given to the patient at the time ofmaking the appointment.

8 On arrival, all of these points shouldbe checked, and any deviations from them 1 Conditions where suboptimal lung function resultsare likelyChest or abdominal pain of any causeOral or facial pain exacerbated by a mouthpieceStress incontinenceDementia or confusional stateATS/ERS: considerations FOR LUNG function MILLER ET 26 NUMBER 1 EUROPEAN RESPIRATORY JOURNALS ubjects should be as relaxed as possible before and during thetests. The decision to avoid long- and short-acting broncho-dilators is a clinical one, dependent on the question beingasked. If the study is performed to diagnose an underlyinglung condition, then avoiding bronchodilators is useful. If thestudy is carried out to determine a response to an existingtherapeutic regimen, then one may choose not to withholdbronchodilator should be asked to loosen tight-fitting should normally be left in place; if they are loose,they may interfere with performance and are, therefore, DETAILSA mbient temperature, barometric pressure and time of daymust be recorded.

9 Temperature is an important variable inmost pulmonary function tests and is often measured directlyby the instrument. The way in which it is measured and usedmay vary from instrument to instrument. For example, it maybe measured with a simple thermometer or an internalthermistor. Regardless of the method used, it is the responsi-bility of the laboratory to confirm the accuracy of temperaturemeasurements, and it is the responsibility of the manufacturerto describe or provide a clear mechanism for checking theaccuracy of instrument temperature measurements. Theyshould also provide instructions on how to respond whenacceptable temperature performance cannot be , when patients return for repeat testing ( a clinic),the equipment and the operator should be the same, and thetime of day should be within 2 h of previous test order for performing lung function tests should take intoaccount the optimum work flow in the laboratory, potentialinfluences of one test on another and the ability of the subjectto undertake the test.

10 One possible order is shown in table should be appropriate delays between tests, as indicatedin the subsequent sections of this series of documents. Otherorders of testing are acceptable ( lung volumes,diffusing capacity, dynamic studies, inhalation of broncho-dilator agent and then repeat dynamic studies, as taken fromtable 3), but the order should be kept constant to avoidintroducing unanticipated variability to test results. The choiceof order of testing should consider the potential effect of onetest on the subsequent test. For example, the measurement ofcarbon monoxide diffusing capacity of the lung (DL,CO)immediately after a nitrogen washout measurement of thetotal lung capacity (TLC) will be affected by the increasedoxygen content in the lungs , unless enough time has passed toallow the oxygen concentration to return to normal.