May 2002 / Volume 47 / Number 5 / Page 570
Take a Deep Breath, Then Blast It Out
Dr Stoller and I used to think that spirometry was as easy as measuring the other vital signs. However, during the last couple of decades we've needed to rely on forced expiratory volume in the first second (FEV1) values to determine the efficacy of dangerous or expensive medications for asthma and chronic obstructive pulmonary disease, and we've learned the hard way to distrust changes in FEV1 until we've viewed the spirograms and flow-volume curves from each spirometry test session (before and after the intervention). Dr Stoller's article in this issue describes the incredible improvement in the quality of bedside spirometry done by respiratory therapists in his hospital after training by pulmonary function laboratory technicians of The Cleveland Clinic Foundation.1
See the Original Study on Page 578
Inaccurate spirometers are finally a rarity: nowadays poorly trained, timid, or harried coaches is the major reason for the high false positive rate of spirometry testing done outside hospital-based pulmonary function labs. Just before Thanksgiving of 2001 I reviewed the results of 1,500 spirometry tests done by respiratory therapists who volunteered to test New York police officers who had responded to the World Trade Center disaster. My confidence in the results would have been much higher if those therapists had first been trained by experienced pulmonary function technicians.
I've learned from Drs Allan Palmer and Alan Coates that the priority for coaching should be: (1) look at the patient and encourage a deep breath; (2) yell "blast out!" and (3) quietly tell the patient to keep on blowing out, while watching the spirometer for feedback. When the new National Lung Health Education Program2,3 (NLHEP) office spirometers become commercially available, clinicians will save time and effort during phase 3 of that maneuver by stopping after only 6 seconds. These new spirometers will substitute the FEV6 for the forced vital capacity, using Dr John Hankinson's National Health and Nutrition Examination Survey (NHANES III) equations for predicted values.4
At the 47th International Respiratory Congress in San Antonio in December of 2001, I presented a "rogue's gallery" of poor quality spirometry at Dr Thomas Petty's NLHEP symposium. I believe that if respiratory therapists learn how to perform good quality spirometry, not only will bedside spirometry become more accurate at detecting airway obstruction and improvements following bronchodilator treatments, they will then be able to offer spirometry training to the office staff of local primary care practitioners, who care for most of the community patients with asthma and chronic obstructive pulmonary disease--ideal clients to provide referrals to home care services, asthma management programs, and pulmonary rehabilitation programs run by respiratory therapists.
Paul L Enright MD
Division of Pulmonary Disease and
Critical Care Medicine
Department of Medicine
University of Arizona
- Stoller JK, Orens D, Hoisington E, McCarthy K. Bedside spirometry in a tertiary care hospital: The Cleveland Clinic Experience. Respir Care 2002;47(5):578-582.
- Information on the National Lung Health Education Program and spirometry available at http://www.nlhep.org/spirom1.html (accessed Mar 4, 2002).
- 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. Chest. 2000;117(4):1146-1161. Respir Care. 2000;45(5):513-530.
- Hankinson JL, Odencrantz JR, Fedan KB. Spirometric reference values from a sample of the general U.S. population. Am J Respir Crit Care Med 1999;159(1):179-187.