Predicted peak expiratory flow: Differences across formulae in the literature

  • Michael S. Radeos
    Department of Emergency Medicine, Massachusetts General Hospital, Boston, MA, USA

    Channing Laboratory, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
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  • Carlos A. Camargo Jr
    Address reprint requests to Carlos Camargo, MD, EMNet Coordinating Center, Department of Emergency Medicine, 326 Cambridge St, Suite 410, Massachusetts General Hospital, Boston, MA 02114 USA
    Department of Emergency Medicine, Massachusetts General Hospital, Boston, MA, USA
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      The study objectives were to examine the differences between Peak Expiratory Flow (PEF) formulae in the literature and to assess the potential impact of those differences on the interpretation of clinical guidelines for asthma management. We calculated 100% PEF values for hypothetical patients at the 50th percentile for height and weight and classified the percent predicted PEF into severity groups according to national asthma guidelines. Choosing different formulae could give an 18 year old man a 100% predicted PEF as low as 501 L/min and as high as 730 L/min (delta = 229 L/min); and a 35 year old woman a classification of severe (46%) using one, but moderate (57%) using another. Predicted PEF varied widely across formulae and choice of formula may alter guideline-based care. We propose recently published population-based equations as the reference standard for future asthma guidelines.


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      1. National Asthma Education Program Expert Panel Report. National Institutes of Health Publication no. 91-3642, Bethesda, MD1991
      2. National Asthma Education Program Expert Panel Report II. National Institutes of Health Publication no. 97-4051, Bethesda, MD1997
        • Godfrey S.
        • Kamburoff P.L.
        • Nairn J.R.
        • et al.
        Spirometry, lung volumes and airway resistance in normal children aged 5 to 18 years.
        Br J Dis Chest. 1970; 64: 15-24
        • Polgar G.
        • Promhadat V.
        Pulmonary function testing in children. WB Saunders, Philadelphia1971
        • Gregg I.
        • Nunn A.J.
        PeaK expiratory flow in normal subjects.
        Br Med J. 1973; 3: 282-284
        • Leiner G.C.
        • Abramowitz S.
        • Small M.
        • et al.
        Expiratory peak flow rate: standard values for normal subjects: Use as a clinical test of ventilatory function.
        Am Rev Respir Dis. 1963; 88: 644-651
        • Le Souef P.N.
        Paediatric prediction equations for PEF (growth, ageing, gender, race and health).
        Eur Respir J. 1997; 10: 75s-79s
        • Hankinson J.
        • Odencrantz J.
        • Ferdan K.
        Spirometric reference values from a sample of the general U.S. population.
        Am J Respir Crit Care Med. 1999; 159: 179-187
        • Pistelli R.
        Population values of lung volumes and flows in children.
        Eur Respir J. 1992; 5: 463-470
        • Schwartz J.D.
        • Katz S.A.
        • Fegley R.W.
        • et al.
        Analysis of spirometric data from a national sample of healthy 6–24 year-olds (NHANES II).
        Am Rev Respir Dis. 1998; 138: 1405-1414
        • Hsu K.H.K.
        • Jenkins D.E.
        • Hsi B.P.
        • et al.
        Ventilatory functions of normal children and young adults—Mexican-American, White, and Black: II. Wright peak flowmeter.
        J Pediatr. 1979; 95: 192-196
        • Nourjah P.
        National Hospital Ambulatory Medical Care Survey.
        National Center for Health Statistics, Hyattsville, MD1999 (no 304)
        • Cherniack R.M.
        • Raber M.B.
        Normal standards for ventilatory function using an automated wedge spirometer.
        Am Rev Respir Dis. 1972; 106: 38-46
        • Knudson R.J.
        • Slatin R.C.
        • Lebowitz M.D.
        • et al.
        The maximal expiratory flow-volumne curve.
        Am Rev Respir Dis. 1976; 113: 587-600
        • Hsu K.H.K.
        • Jenkins D.E.
        • His B.P.
        • et al.
        Ventilatory functions of normal children and young adults—Mexican-American, White and Black: I. Spirometry.
        J Pediatr. 1979; 95: 14-23
        • Roca J.
        • Sanchis J.
        • Agusti-Vidal A.
        • et al.
        Spirometric reference values from a Mediterranean population.
        Bull Eur Physiopathol Respir. 1986; 22: 217-224
      3. National Center for Health Statistics: Anthropometric reference data and prevalence of overweight. Bethesda, MD: Vital and Health Statistics. Series 11. No. 238 1976–1980

        • Silverman R.
        • Scharf S.M.
        Pulmonary function testing in the emergency department.
        in: Brenner B.E. Emergency Asthma. Marcel Dekker, New York1999: 233-252
        • Diner B.
        • Brenner B.
        • Camargo Jr, C.A.
        Inaccuracy of “personal best” peak expiratory flow rate reported by inner-city patients with acute asthma.
        J Asthma. 2001; 38: 127-132
        • Chia S.E.
        • Wang Y.T.
        • Chan O.Y.
        • et al.
        Pulmonary function in healthy Chinese, Malay and Indian adults in Singapore.
        Ann Acad Med Singapore. 1993; 22: 878-884