Peak Expiratory Flow With or Without a Brief Postinspiratory Pause

doi:10.1378/chest.128.1.442

Chest

Volume 128, Issue 1, July 2005, Pages 442-445

https://doi.org/10.1378/chest.128.1.442 Get rights and content

Background

The duration of postinspiratory pause prior to forced expiration may significantly influence the peak expiratory flow (PEF) measured during maximal forceful expirations. In comparison with maneuvers without a postinspiratory pause, maneuvers with 4 to 6-s pause at total lung capacity (TLC) result in decreased PEF values. The extent to which brief pauses (< 2 s) similarly affect PEF values is unknown.

Methods

Thirty-six healthy volunteers (mean [±SD] age, 35 ± 8 years; 18 men) performed a series of maximal forceful expirations with two different types of maneuvers. One maneuver (NP) included no inspiratory pause at TLC prior to forceful expiration, whereas the second (P) included a brief pause (≤ 2 s). The speed of inhalation to TLC was rapid and similar for both maneuvers. The highest PEF for each maneuver was used for analysis.

Results

The maximal PEF did not differ (p > 0.05) between the P and NP maneuvers (7.78 ± 1.45 vs 7.83 ± 1.45 L/s, respectively). Comparison of the intermaneuver differences showed a bias of 0.05 L/s and 95% confidence interval in the range of −0.9 to 1.0 L/s.

Conclusions

Forceful expiratory maneuvers with or without postinspiratory pauses of ≤ 2 s produce identical maximal PEF values and, therefore, can be used interchangeably for the spirometric measurement of PEF in healthy subjects.

Section snippets

Materials and Methods

Thirty-six healthy volunteers (mean age, 36 ± 8; 18 men) participated in the study. All of the subjects were nonsmokers; had no history of asthma, cough, or recent respiratory infection; and were not taking medications during the study. The subjects were nai¨ve to the purpose of the study and all but two had never performed spirometry before. The research was approved by the institutional ethics committee, and informed consent was obtained from all of the subjects.

Respiratory flow was measured

Results

Figure 1shows the typical volume and flow tracings with each expiratory maneuver. There were no differences in the best PEF or average PEF between the two maneuvers (Table 1). With the P maneuver, the best PEF was achieved with the first three trials in 78% of the individual blows, whereas with the NP, the best PEF was achieved with the first three trials in 75% of the individual blows. In 52% of the individual blows, the best PEF was achieved with the NP maneuver and in 45% of the individual

Discussion

The two maneuvers differed only in the duration of inspiration, with the NP maneuver containing essentially no inspiratory pause. The subjects were asked to inhale rapidly to TLC, but no other instructions were given about the vigor of inspiration. With regard to breathhold at TLC, the subjects were simply instructed to pause until they heard the cue for forceful expiration.

Agreement of the maneuvers was analyzed with the method by Bland and Altman,¹² which showed that the mean intermaneuver

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Cited by (3)

Inter-session reproducibility of peak expiratory flow with standardized expiratory maneuvers
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Citation Excerpt :
In contrast, a breath-hold at TLC neutralizes the effect of fast inspiration on the effective elastic recoil pressure; it allows stress relaxation in both the airway wall and lung parenchyma to occur and thus increases the airway compliance and decreases the effective lung elastic recoil pressure.5,8,26 Long post-inspiratory pauses at TLC may also offset the augmentation of expiratory muscle force related to stretch-shorten cycle.9,27 With pauses of about 4–6 s at TLC, the decreases in PEF may range from 6 to 13% in the healthy volunteers.5,7,23
In adults performing forceful expiratory maneuvers, the length of post-inspiratory pause prior to forced expiration may influence the subsequently measured peak expiratory flow (PEF) and increase its variability. We investigated the effects of two different lengths of breath-hold at total lung capacity (TLC) on the short-term reproducibility of PEF in healthy volunteers.
Forty-six healthy volunteers (age 34.6±8.5; 23 men) performed a series of maximal forceful expirations in two different test sessions, separated by approximately 2 weeks. In each test-session, PEF was measured with two different types of maneuvers. One maneuver (P) included a brief (<2 s) post-inspiratory pause at TLC prior to forced expiration, whereas the second maneuver (NP) included no pause at TLC. The speed of inspiration to TLC was fast and similar for both maneuvers. In a given test session, all volunteers performed four efforts for each type of maneuver. The highest PEF for each maneuver was used for analysis. The Bland–Altman statistical analysis was used to determine inter-session reproducibility of PEF.
Within-maneuver analysis of the between-test session reproducibility of PEF showed that neither maneuver systematically biased the measured PEF (mean difference 0.02 L/s for the P and 0.17 L/s for the NP maneuver). Inter-maneuver between-test session analysis similarly showed that neither maneuver introduced a systematic bias in the maximal PEF (mean difference ranged from −0.15 to −0.01 L/s). The limits of agreement were comparable in all maneuver-pair analyses.
Forceful expiratory maneuvers with or without a brief (<2 s) pause at TLC produce comparable PEF values in test–retest sessions.
Earlier decline in sniff nasal inspiratory pressure than peak expiratory flow in children with Duchenne muscular dystrophy
2014, European Respiratory Journal
Spirometric parameters in malnourished girls with anorexia nervosa
2008, Journal of Physiology and Pharmacology

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Chest

Selected ReportsPeak Expiratory Flow With or Without a Brief Postinspiratory Pause

Background

Methods

Results

Conclusions

Section snippets

Materials and Methods

Results

Discussion

Chest

Chest

Chest

Chest

The Peak Flow Working Group: physiological determinants of peak expiratory flow

Eur Respir J Suppl

Dependence of maximal flow-volume curves on time course of preceding inspiration

J Appl Physiol

Inspiratory maneuver effects on peak expiratory flow: role of lung elastic recoil and expiratory pressure

Am J Respir Crit Care Med

Dependence of maximal flow-volume curves on time course of preceding inspiration in patients with chronic obstruction pulmonary disease

Am J Respir Crit Care Med

Dependence of forced vital capacity manoeuvre on time course of preceding inspiration in patients with restrictive lung disease

Eur Respir J

The effect of inspiratory maneuvers on expiratory flow rates in health and asthma: influence of lung elastic recoil

Am J Respir Crit Care Med

Maximal dynamic expiratory pressures with fast and slow inspirations

Eur J Appl Physiol

Selected Reports
Peak Expiratory Flow With or Without a Brief Postinspiratory Pause