Peak Expiratory Flow Prediction
This equation is taken from Hankinson et al (1999), based on evaluation of 7429 asymptomatic, lifelong nonsmoking participants aged 8 to 80 years in the third National Health and Nutrition Examination Survey (NHANES III). This survey included caucasian, African-American, and Mexican-American patients, with extrapolation of the latter group to other hispanics. Age and height were significantly associated with peak expiratory flows (PEF) in all subgroups. Weight was associated with PEF, but this association disappeared when height was considered. Previous equations used to calculate predicted PEF have also been developed, but were based on smaller sample sizes and often included only specific subgroups (Radeos et al, 2004).
- [1]Hankinson J et al.: Spirometric reference values from a sample of the general U.S. population.American Journal of Respiratory and Critical Care Medicine 1999, 159 (1): 179-87
- [2]Radeos MS, Camargo CA.: Predicted peak expiratory flow: differences across formulae in the literature.American Journal of Emergency Medicine 2004, 22 (7): 516-21
- [3]Available from: http://www.ginasthma.org.Global Strategy for Asthma Management and Prevention, Global Initiative for Asthma (GINA) 2007.
Results
Real-time automated computation
PEF must also be considered in context of previous values, although these are known in a minority of patients. Change in PEF compared to the patient's previous best is more important than the predicted PEF using these equations. A decline in PEF to <60 % of a patient's baseline PEF indicates a severe exacerbation.
This equation is taken from Hankinson et al (1999), based on evaluation of 7429 asymptomatic, lifelong nonsmoking participants aged 8 to 80 years in the third National Health and Nutrition Examination Survey (NHANES III). This survey included caucasian, African-American, and Mexican-American patients, with extrapolation of the latter group to other hispanics. Age and height were significantly associated with peak expiratory flows (PEF) in all subgroups. Weight was associated with PEF, but this association disappeared when height was considered. Previous equations used to calculate predicted PEF have also been developed, but were based on smaller sample sizes and often included only specific subgroups (Radeos et al, 2004).
- [1]Hankinson J et al.: Spirometric reference values from a sample of the general U.S. population.American Journal of Respiratory and Critical Care Medicine 1999, 159 (1): 179-87
- [2]Radeos MS, Camargo CA.: Predicted peak expiratory flow: differences across formulae in the literature.American Journal of Emergency Medicine 2004, 22 (7): 516-21
- [3]Available from: http://www.ginasthma.org.Global Strategy for Asthma Management and Prevention, Global Initiative for Asthma (GINA) 2007.