Peak expiratory flow

Classification of asthma severity is based on daytime and nighttime symptoms, physical activity, lung function, variability in peak expiratory flow (PEF), and use of reliever medications. 

FEV, forced expiratory volume in 1 second PEF, peak expiratory flow MDI, metered-dose inhaler DPI, dry powder inhaler. 

FIGURE 11-2. Home management of acute asthma exacerbation. Patients at risk for asthma-related death should receive immediate clinical attention after initial treatment. PEF, peak expiratory flow. 

FIGURE 11-3. Emergency department and hospital-based management of asthma exacerbation. FEV-, forced expiratory volume in 1 second Pco2, partial arterial pressure of carbon dioxide PEF, peak expiratory flow 02, oxygen. (From Kelly HW, Sorkness CA. Asthma. In DiPiro JT, Talbert RL, Yee GC, et al, (eds.) Pharmacotherapy A Pathophysiologic Approach. 6th ed. New York McGraw-Hill 2005 517, with permission.)... 

PEFR Peak expiratory flow rate QS Quantity sufficient... 

Peak expiratory flow The maximum flow rate of air leaving the lungs upon forced exhalation. 

Peak expiratory flow (PEF) and FEVj are less than 50% of normal predicted values. Pulse oximetry reveals decreased arterial oxygen and 02 saturations. The best predictor of outcome is early response to treatment as measured by improvement in FEVj at 30 minutes after inhaled /12-agonists. 

FIGURE 80-2. Home management of acute asthma exacerbation. Patients at risk of asthma-related death should receive immediate clinical attention after initial treatment. Additional therapy may be required. (MDI, metered-dose inhaler PEF, peak expiratory flow.) (Adapted from NHLBI, National Asthma Education and Prevention Program, Expert Panel Report 2. Guidelines for the Diagnosis and Management of Asthma. NIH Publication No. 97-4051. Bethesda, MD U.S. Department of Health and Human Services, 1997.)... 

Peak expiratory flow measurements are not adequate for diagnosis of COPD because of low specificity and a high degree of effort dependence. However, a low peak expiratory flow is consistent with COPD. 

Atmospheres were within a few percent of nominal concentrations the mean oxygen concentration was approximately 20.5%. No significant or consistent differences were found between air exposure and test chemical exposure for clinical observations, blood pressure, heart rate, peak expiratory flow, or EKG recordings. During blood sampling and blood pressure measurements, all subjects showed sinus arrhythmia before and after exposure. 

Effects No effects on tested parameters of blood pressure, heart rate, electrocardiogram (EKG) rhythms, or lung peak expiratory flow. 

Obstructive disease reduces peak expiratory flow rate (PEFR) and increases RV via gas trapping. The TLC may also be higher although this is difficult to demonstrate without values on the x axis. The important point to demonstrate is reduced flow rates during all of expiration, with increased concavity of the expiratory limb owing to airway obstruction. The inspiratory limb is less affected and can be drawn as for the normal curve but with slightly lower flow rates. 

McMillan, R. S., D. H. Wiseman, B. Hanes, and P. F. Wehrle. Effect of oxidant air pollution on peak expiratory flow rates in Los Angeles school children. Arch. Environ. Health 18 941-949, 1%9. 

Therefore, self-monitoring by the use of home peak expiratory flow meters is an essential part of the therapeutic program. With proper education, the patient can detect early signs of deterioration and can adjust medication within the framework of a physician-directed therapeutic regimen. 

From U. S. Department of Health and Human Service, National Institutes of Health, National Heart, Lung and Blood Institute July 1997. FEVi, forced expiratory volume in 1 second (values < 100% indicate increased airway obstruction) PEF, peak expiratory flow (greater variability indicates less control of disease). 

Contact allergy to glucocorticoids is not rare in patients with atopic dermatitis. In patients with known contact allergy to budesonide, allergic skin reactions can also occur when inhaled forms of the drug are used, as shown by a randomized, double-bhnd, placebo-controlled study in 15 non-asthmatic patients with budesonide hypersensitivity on patch testing (101). In four of seven patients who used inhaled budesonide, there was reactivation of the 6-week-old patch test sites and they had new distant skin lesions. No flare-up reactions were observed in the other 11 patients (three had used inhaled budesonide and eight placebo for 1 week). None of the patients developed respiratory symptoms spirometry and peak expiratory flow rates remained normal. 

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