October 2002 / Volume 47 / Number 10 / Page 1145
To Blow or Not to Blow—That Is the Question
To be, or not to be—that is the question—
Shakespeare, Hamlet, III, i, 57
Our man Hamlet was clearly in a quandary when he uttered those words, but a similar quandary faces us today when we come to the question of whether we should screen for lung disease by performing spirometry.
Long before the formation of the National Lung Health Education Program, members of the pulmonary community had frequently called for the wider use of spirometry to stem the tide of rising mortality due to lung disease.1 Yet it would appear that those calls for the general use of spirometry have largely fallen on deaf ears. Why?
See the Original Study on Page 1150
Current standards of medical practice hold that if one suspects heart disease or if a patient is considered at risk for heart disease, then obtaining an electrocardiogram or, at the least, measuring blood pressure is indicated. No physician would even consider not measuring blood pressure, even with a patient who is seen only for a routine visit. So why is it that spirometry is not a routine test? Indeed, it is unclear why the spirometer has not joined the thermometer, sphygmomanometer, chest radiograph, and electrocardiograph as a prominent tool in the physician's office. Perhaps we can gain some insight into this paradox if I relate to you a recent experience.
As part of a steering committee for an upcoming conference, I attended a meeting to discuss the election of speakers on the latest approaches to the management of chronic obstructive pulmonary disease. One of the committee members is a practicing physician in the area, who was participating via conference call from his office. When the inclusion of spirometry as a conference topic came up, we asked him if that topic would be attractive to the private physician and also did he routinely use spirometry in his office. He immediately went on the defensive and stated that he was too busy; he had 3 examination rooms full of patients, no time to do spirometry, and, "Besides, if you can't do it right, why do spirometry at all!" I thought to ask him if he felt the same way about blood pressure, height, and weight measurements, but held my tongue. Why did our busy pulmonary physician not routinely use spirometry in his practice, when we now know the merits of this clinical test? I believe there are 4 major misconceptions or perceived obstacles that keep physicians and other health care workers from using this exceptionally useful test.
1. Spirometry Is a Poor Test and of Little Benefit
Nothing could be further from the truth. If you perform spirometry or teach about it, I strongly encourage you to read the National Lung Health Education Program's recent position paper.2 The take-home message is that spirometry is one of the best clinical tests we have. For example, how many clinical tests do you know of that reproduce with a coefficient of variation of ± 2-3%?3,4 Did you know that spirometry (forced vital capacity [FVC]) beat out blood pressure as a predictor of heart disease in the Framingham Study?5 And did you know that spirometry (forced expiratory volume in the first second [FEV1]) is the best predictor of mortality due to all causes?6,7 Clearly, spirometry is not only a good clinical test, it might just be an outstanding clinical test.
2. The Equipment Is Bulky, Not Very Good, and Expensive
This used to be true, but not any longer. The efforts of the American Thoracic Society to improve spirometers and spirometry3 have all but eliminated poor spirometer performance. That is not to say that any given spirometer is always working correctly; spirometers are more complex than sphygmomanometers, making them more prone to problems. However, most problems are solved by a quality control program of device calibration and testing of laboratory personnel.2,8 The bulkiness of spirometers has disappeared with the advent of flow sensors, lap-top computers, and microprocessor chips. Now a perfectly good spirometer can be the size of a hand-held video game. The cost has fallen also. In this issue of RESPIRATORY CARE the report by Schoh et al9 used such a modern spirometer, which cost about $500, with 394 people at a health fair, and with great success. The bulkiness, accuracy, and cost barriers to spirometry are gone.
3. Spirometry Is Hard to Do Right
If spirometry is that hard to do right, then why are so many scientific reports written and published in which the major outcome variable is spirometry values? If spirometry is so hard to do right, why did Schoh et al9 choose to measure FEV1 at a health fair to test 394 people? A pulmonary function laboratory that I once directed was accused of slowing down patient flow by our insistence on performing spirometry prior to the patient seeing the physician—apparently a novel concept! We set up a quality-assurance/quality-control project that showed that a spirometry study that included bronchodilation took about 15 minutes. Spirometry alone (but with time taken for height, weight, and data entry) took a mere 5-7 minutes. Most physicians typically see 8-12 patients in a half-day clinic. Given that you can charge for the test…well, you get the picture.
The real Achilles heel of spirometry is that, unlike other routine clinical tests, it requires active and maximal participation by the subject, and one of the keys to successful spirometry is the person administering it. Administering spirometry takes good coaching skills that not everyone has.3,7 Remember, though, that even substandard spirometry tests are still interpretable,3,4 and failure to perform spirometry properly is one indicator of disease.10 Indeed, the report by Schoh et al9 demonstrates that it is very feasible to conduct spirometry in the general public in a suboptimal setting. So it is hard to believe that spirometry is so time-consuming or hard to do right that this should be a real barrier to the use of spirometry.
4. What Do All the Numbers Mean and What Do I Do with Them?
I submit that this is the real barrier to the general use of spirometry. I am often asked for references about spirometry interpretation, and, sad to say, there are limited offerings. While there are many articles on theory, equipment, and performance, there is little to be found in textbooks on fundamental interpretation of test results. This state of affairs is best observed when the new first-year pulmonary fellows arrive each July. When presented with a flow-volume loop, or even just FEV1/FVC, they are at a total loss as to how to interpret these findings This is in sharp contrast to when they are presented with a 12-lead electrocardiogram, which they handle as though they were born cardiologists. So why the difference? The answer is simple. It's the education they receive. Most tell me that they receive little if any instruction in lung function testing, or its interpretation, in medical school or during residency, whereas from the beginning they are exposed to advanced measures of heart performance and their interpretation.
Currently, mortality due to lung disease is ranked number 4 and is projected to rise to number 3 by 2020.11,12 This dramatic rise in death rates due to lung disease comes in face of the fact that the other 6-8 leading causes of mortality in this country continue to fall. And while the number of patients with doctor-diagnosed chronic obstructive pulmonary disease is estimated at 10 million, the number of people in the general population with abnormal lung function is estimated at 24 million; accordingly, the under-diagnosis of lung disease may approach some 14 million persons.12
The best way to meet these challenges is education. Yet our doctors, respiratory therapists, and other health-related professionals are not receiving even cursory education in the use and value of spirometry, in spite of the fact that spirometry is one of the best clinical tests we have. This failure is the fault of our education system. The pulmonary community has not made it a priority to educate others in the value, performance, and, most of all, the interpretation of even basic office spirometry. And the situation was the same more than 20 years ago, when it was observed:
Perhaps even greater responsibility for the near absence of the use of pulmonary function in the prevention of chronic limitation of airflow must be borne by the expert in pulmonary medicine, especially in his relation to the nonspecialist. If evaluation of pulmonary function is to play a significant role in the prevention of chronic limitation of airflow, it is the pulmonary specialist who is in the best position to educate the rest of the health professions; yet the pulmonary specialist is no more likely to use pulmonary function for prevention than the nonpulmonary specialist.1
Or perhaps, as the comic strip character Pogo would say, "We have met the enemy and they is us." So what are we going to do about it?
Charles G Irvin PhD
Vermont Lung Center
College of Medicine
University of Vermont
- Permutt S. Pulmonary function testing and the prevention of pulmonary disease. Chest 1978;74(6):606-610.
- Ferguson GT, Enright PL, Buist AS, Higgins MW. Office spirometry for lung health assessment in adults: a consensus statement from the National Lung Health Education Program. Respir Care 2000;45(5):513-530.
- American Thoracic Society. Standardization of spirometry, 1994 update. Am J Respir Crit Care Med 1995;152(3):1107-1136.
- American Thoracic Society. Lung function testing: selection of reference values and interpretative strategies. Am Rev Respir Dis 1991;144(5):1202-1218.
- Kannel WB, Seidman JM, Fercho W, Castelli WP. Vital capacity and congestive heart failure. The Framingham Study. Circulation 1974;49(6):1160-1166.
- Weiss ST, Segal MR, Sparrow D, Wager C. Relation of FEV1 and peripheral blood leukocyte count to total mortality. The Normative Aging Study. Am J Epidemiol 1995;142(5):493-498.
- Schunemann HJ, Dorn J, Grant BJ, Winkelstein W Jr, Trevisan M. Pulmonary function is a long-term predictor of mortality in the general population: 29-year follow-up of the Buffalo Health Study. Chest 2000;118(3):656-664.
- Wanger J, Irvin CG. Office spirometry: equipment selection and training of staff in the private practice setting. J Asthma 1997;34(2):93-104
- Schoh RJ, Fero LJ, Shapiro H, Aslor JP, Kaelin OJ, Rollins DR, et al. Performance of a new screening spirometer at a community health fair. Respir Care 2002;47(10):1150-1157.
- Eisen EA, Dockery DW, Speizer FE, Fay ME, Ferris BG Jr. The association between health status and the performance of excessively variable spirometry tests in a population-based study in 6 U.S. cities. Am Rev Respir Dis 1987;136(6):1371-1376.
- Pauwels RA, Buist AS, Calverley PM, Jenkins CR, Hurd SS. Global strategy for the diagnosis, management, and prevention of chronic obstructive pulmonary disease. NHLBI/WHO Global Initiative for Chronic Obstructive Lung Disease (GOLD) Workshop summary. Am J Respir Crit Care Med 2001;163(5):1256-1276; Respir Care 2001;46(8):798-825.
- Mannino DM, Homa DM, Akinbami LJ, Ford ES, Redd SC. Chronic obstructive pulmonary disease surveillance - United States, 1971-2000. MMWR Surveillance Summaries 2002;51(SS06);1-16. Available at http://www.cdc.gov/mmwr/preview/mmwrhtml/ss5106a1.htm. Respir Care 2002;47(10):1184-1199.