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ORIGINAL ARTICLE
Year : 2016  |  Volume : 14  |  Issue : 1  |  Page : 11-13

A study of postural variation in peak expiratory flow rates in healthy adult female subjects in South India


Department of Physiology, MVJ Medical College and Research Hospital, Hoskote, Bengaluru, Karnataka, India

Date of Web Publication26-Feb-2016

Correspondence Address:
Jenny Jayapal
Department of Physiology, MVJ Medical College and Research Hospital, Hoskote, Bengaluru, Karnataka
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/1118-4647.177531

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  Abstract 

Background: Peak expiratory flow rate (PEFR) reflects the strength and condition of respiratory muscles and the degree of airflow limitation in large airways. PEFR shows postural variation that follows a specific pattern in asthmatics and healthy individuals has been identified. Adequate data are not available for the postural variation in normal individuals, who are students in professional courses, and had a sedentary lifestyle. Lung volumes in normal subjects were significantly higher in a standing position. Others have reported that in healthy subjects spirometric indices were higher in the standing in comparison with the sitting position whereas other studies have reported no differences between spirometric values obtained in lying, sitting, and standing positions. Hence, this study is undertaken to study the postural variation in PEFR in healthy adult female subjects in South India. Methods: PEFR was recorded in 50 adult healthy female students aged 18-23 years and studying in professional courses (MBBS, BDS, Nursing, and MSc). Mini wright's peak flow meter was used to measure the PEFR. Three readings were taken PEFR in standing and lying posture. Best of three recordings is taken as the final value. Results: PEFR is decreased in lying posture compared to standing posture in subjects studied, and the quantum of difference was noted. Conclusion: In postural changes, PEFR measurements significantly differ based on whether the measurements are taken in the standing or in the lying posture in healthy participants. The effect of posture may be of importance in recording PEFR and changing to a better posture may be especially useful for those patients with weak expiration.

Keywords: Peak expiratory flow rate, postural variation, South Indian female


How to cite this article:
Jayapal J. A study of postural variation in peak expiratory flow rates in healthy adult female subjects in South India. Niger J Gen Pract 2016;14:11-3

How to cite this URL:
Jayapal J. A study of postural variation in peak expiratory flow rates in healthy adult female subjects in South India. Niger J Gen Pract [serial online] 2016 [cited 2019 Aug 25];14:11-3. Available from: http://www.njgp.org/text.asp?2016/14/1/11/177531


  Introduction Top


Peak expiratory flow rate (PEFR) reflects the strength and condition of respiratory muscles and the degree of airflow limitation in large airways. PEFR shows postural variation that follows a specific pattern in asthmatics and healthy individuals has been identified. Adequate data are not available for the postural variation in normal individuals, who are students in professional courses, and had a sedentary lifestyle. Hence, this study is undertaken to the postural variation in PEFR's in healthy adult female subjects in South India.

Peak expiratory flow is a measurement of the movement of air into and out of the lungs during various breathing maneuvers. [1]

In effect of postural changes, lung volumes in normal subjects were significantly higher in a standing position. [2] Other studies reported that in healthy subjects spirometric indices were higher in the standing in comparison with the sitting position, [3] whereas some other studies have reported no differences between spirometric values obtained in lying, sitting, and standing positions. [4]

This study is undertaken to the postural variation in PEFRs in healthy adult female subjects in South India.


  Methods Top


The present study was conducted in the pulmonary function lab of Chettinad Medical College at Chennai, India. A total of 50 apparently healthy sedentary female subjects aged 18-23 years and studying in professional courses (MBBS, BDS, Nursing, and MSc). Mini wright's peak flow meter was used to measure the PEFR. Three readings were taken PEFR in standing and lying posture. Best of three recordings is taken as the final value.

Ethical clearance was obtained from institution ethical committee.

Before starting the actual study, subjects were briefed on the protocol and informed consent was obtained. Thorough history regarding suitability as per the above inclusion and exclusion criteria was elicited. The basic clinical examination was done to rule out any cardiopulmonary or other illness.

Statistical analysis

To analyze the diurnal variation of PEFR, the maximum out of the three recordings was taken as the final value.

Peak expiratory flow rate was measured in standing, and lying position was analyzed by using one-way ANOVA followed by Tukey's test with P < 0.05 was taken, as the level of significance.


  Results Top


The anthropometric values of the subjects are given in [Table 1]. On analysis of PEFR records of individual subjects, it was seen that there was an overall dip in PEFR values in lying down posture [Table 2].
Table 1: Basic subject information

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Table 2: Mean PEFR values of standing and lying posture for female subjects

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  Discussion Top


In this study, postural change of healthy female individuals was studied. Our results show that PEFR is decreased in lying posture compared to standing posture in female subjects studied. These study findings are in contrast to the findings reported by Baduraddin et al. 2010. [4] They have reported that there was no significant difference of PEFR in standing, sitting, and lying position Our study findings are similar to the reports of Fiz et al. 1991 where they have reported that maximum inspiratory and expiratory pressures values decreased in the supine posture with respect to standing and sitting positions. [5]

In the erect posture the diaphragm descends, therefore, the capacity of the thoracic cage increases. In the supine position, the diaphragm is pulled upward because the abdominal viscera push the diaphragm. Therefore, the capacity of the thoracic cage decreases. Hence, vital capacity is greater in the erect posture than in the supine position. In the supine position due to the elimination of the effect of gravity, the blood flow to the lung increases. This decreases vital capacity. In the standing posture, blood is pooled in the lower extremities, therefore venous return decreases. This decreases pulmonary blood flow, thus vital capacity increases on standing.

Increased lung volumes in the standing position appear to be related to the increased thoracic cavity volume. [4] Increased lung volume leads to greater elastic recoil. Following a deep inspiration (as in preparation for a maximal expiratory manoeuvre), a larger amount of potential energy is stored in the tissue of the chest wall. Further, the contracting diaphragm increases pressure on abdominal contents pushing them forward and distending the abdominal cavity. This places the abdominal muscles at a slight stretch. Expiratory muscles attain their optimal length during standing and at more stretched lengths, the abdominal muscles may be more capable of stronger contractions and thus help in the generation of higher maximum expiratory pressure (MEP).

During a forced expiration in standing, the greater recoil of the lung and chest wall is combined with higher pressures generated by abdominal contraction. This combined action push the air at high speeds through narrowing airways resulting in the higher MEP and PEFR. Other factors that may have influenced the results in the standing position could include subject comfort and a higher arousal level.


  Conclusion Top


In postural changes, PEFR measurements significantly differ based on whether the measurements are taken in the standing or in the lying posture in healthy participants. The effect of posture may be of importance in recording PEFR and changing to a better posture may be especially useful for those patients with weak expiration.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 
  References Top

1.
Crapo RO. Pulmonary-function testing. N Engl J Med 1994;331:25-30.  Back to cited text no. 1
    
2.
Appel M, Childs A, Healey E, Markowitz S, Wong S, Mead J. Effect of posture on vital capacity. J Appl Physiol 1986;61:1882-4.  Back to cited text no. 2
[PUBMED]    
3.
Lalloo UG, Becklake MR, Goldsmith CM. Effect of standing versus sitting position on spirometric indices in healthy subjects. Respiration 1991;58:122-5.  Back to cited text no. 3
    
4.
Badaruddin M, Uddin MB, Khalun MF, Ahmad K. Study on peak expiratory flow rate in different positions. Dinajpur Med Coll J 2010;3:17-8.  Back to cited text no. 4
    
5.
Fiz JA, Aguilar X, Carreres A, Barbany M, Formiguera X, Izquierdo J, et al. Postural variation of the maximum inspiratory and expiratory pressures in obese patients. Int J Obes 1991;15:655-9.  Back to cited text no. 5
    



 
 
    Tables

  [Table 1], [Table 2]



 

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Abstract
Introduction
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