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Letters to the Editor

Indian Pediatrics 2002; 39: 104-106  

Peak Expiratory Flow Rate in Children - A Ready Reckoner


Peak Expiratory Flow Rate (PEFR) is an important parameter in the management of bronchial asthma. Measurement of PEFR in bronchial asthma is similar to measurement of blood pressure in managing hypertension and meausrement of blood glucose in managing diabetes mellitus. Peak expiratory flow provided a simple quantitative and repro-ducible measure of resistance and severity of airflow obstruction. Peak expiratory flow can be measured with inexpensive and portable peak expiratory flow meter. Peak flow monitoring can be used for short term monitoring, managing exacerbations and daily long term monitoring. When used in these ways, the patient’s measured personal best is the most appropriate reference value(1).

Many normograms are available for peak expiratory flow rate in children. Though the patient’s measured personal best is the most appropriate reference value, in office practice, to assess a patient’s appropriate peak expiratory flow rate, we have been using a formula as follows:

PEFR = (Ht – 100) × 5 + 100

(Ht = Standing height in cm)

We find that this formula serves as a rough tool for calculating the expected peak expiratory flow rate for individual patients. We have also compared PEFR values obtained from our formula with those obtained from frequently used and quoted prediction equations and normograms in Table I. Comparison of mean of PEFR values for three standing heights with PEFR values obtained for the same heights from our formula is shown in Table II. There is also a close correlation of PEFR prediction curves of the proposed formula with those of other (Fig. 1).

Mnemonics for parameters such as weight, height and blood pressure have been widely used by Pediatricians. In a similar vein, we propose that the above described formula can be used effectively, in office practice, for quick assessment of asthmatic children with a height of 100 cm and more.

Table I__PEFR Values From Our Formula and Other Prediction Equations and Normograms
Standing height (cm)

PEFR

Proposed formula Swaminathan(2) Hsu(3) Godfrey(4)
110 150 160.06 171 NA*
115 175 179.91 190 NA*
120 200 199.76 210 212
125 225 219.61 232 NA*
130 250 239.46 254 NA*
135 275 259.31 279 NA*
140 300 279.16 304 318
145 325 299.01 330 NA*
150 350 318.86 358 NA*
155 375 338.71 388 NA*
160 400 358.56 418 423
165 425 378.41 450 NA*
170 450 398.26 489 NA*
175 475 418.11 518 NA*
180 500 437.96 554 NA*
NA* : Data not available.
Table II__Comparison of PEFR Values From Our Formula with Mean From Two Available Prediction Equations and One Normogram+(2-4)
Standing height (cm) Mean of PEFR values+ PEFR values from our formula
120 207.25 200
140 300.39 300
160 399.85 400

Fig. 1. PEFR values plotted against standing height. Comparison of PEFR prediction curves obtained from the proposed formula with those of other authors(2-4).

S. Balasubramanian,
N.R. Ravikumar,
Elavazhagan Chakkarapani,
S.O. Shivbalan
,
Department of Pediatrics,
Kanchi Kamakoti Childs Trust Hospital,
12 A, Nageswara Road,
Nungambakkam,
Chennai 600 034, India.
E-mail: [email protected]

 References


1. Bethesda MD, US. Expert Panel Report. Guidelines for the Diagnosis and Management of Asthma. National Asthma Education Program, National Heart, Lung and Blood Institute, Department of Health and Human Services, (NIH Pub No 97-4051), 1997.

2. Swaminathan S, Venkatesan P, Mukunthan R. Peak expiratory flow rate in South Indian Children. Indian Pediatr 1993; 30: 207-210.

3. Hsu KHK, MD, Jenkins DE, Hsi BP. J Pediatr 1979; 95: 192-196.

4. Godfrey S, Kamburoff PL, Nairn JR. Spirometry, lung volumes and airway resistance in normal children aged 5 to 18 years. Br J Dis Chest 1970; 64: 15-14.

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