Chest
Volume 104, Issue 2, August 1993, Pages 448-453
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Clinical Investigation
Maximal Inspiratory Pressure: Learning Effect and Test-Retest Reliability in Patients With Chronic Obstructive Pulmonary Disease

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Reliability of the maximal inspiratory pressure (PImax) was examined by measuring PImax once a week for 4 weeks in 91 patients with chronic obstructive pulmonary disease using an aneroid pressure gauge. Five PImax trials were conducted at each test. From the first to the fourth test, the PImax increased by a mean of 9 cm H2O (SD = 10). From the third to the fourth test, PImax increased by a mean of 2 cm H2O and performance appeared to be plateauing. The test-retest reliability coefficient was r=0.97 for PImax measured at the third and fourth test session. The 95 percent confidence interval for the absolute difference in PImax at the third and fourth test was 3 to 5 cm H2O. We conclude that performance of PImax improves with practice in naive COPD patients and PImax is reliable when measured with an aneroid gauge by experienced data collectors if patients are given sufficient practice.

Section snippets

Method

Data for this study were acquired from COPD patients during a 4-week period prior to participating in a pulmonary rehabilitation program. The study was approved by the appropriate institutional committees on human research and informed consent was obtained from all patients. Patients qualified for the study if they (1) had clinically stable COPD with moderate to severe airflow obstruction (FEV1 <65 percent predicted), (2) had no clinical evidence of asthma and <30 percent improvement in FEV1

Results

The sample was 69 men and 22 women with moderate to severe COPD (Table 1). Most patients were taking standard pharmacologic therapies, including inhaled β-agonists, oral β-agonists, and methylxanthines. Nine were using home oxygen. Ten were currently smoking, one had never smoked, and the remainder had quit smoking. The sample was middle class as indicated by the Hollingshead Index.12

Performance gradually improved as demonstrated by the mean (SD) PImax for each test session: first −53 (24) cm H2

Discussion

The mean PImax was consistent with values reported for similar groups of patients with moderate to severe COPD.4,13, 14 The results of this study supported the notion that in naive COPD patients, performance of PImax improves with practice of the PImax maneuver. The third and fourth test of PImax produced reliable data.

ACKNOWLEDGMENTS

We gratefully acknowledge the Bioinstrumentation and Biostatistics Facilities of the Research Resources Center, University of Illinois at Chicago, which provided support services necessary to conduct this study.

References (23)

  • MorrisonNJ et al.

    Respiratory muscle performance in normal elderly subjects and patients with COPD

    Chest

    (1989)
  • MayosM et al.

    Measurement of maximal static respiratory pressures at the mouth with different air leaks

    Chest

    (1991)
  • ClausenJL.

    Maximal inspiratory and expiratory pressures

  • RingquistT.

    The ventilatory capacity in healthy subjects

    Scand J Clin Lab Invest

    (1966)
  • BlackLF et al.

    Maximal respiratory pressures: normal values and relationship to age and sex

    Am Rev Respir Dis

    (1969)
  • LarsonJL et al.

    Reliability of maximal inspiratory pressure

    Nurs Res

    (1987)
  • McElvaneyG et al.

    Maximal static respiratory pressures in the normal elderly

    Am Rev Respir Dis

    (1989)
  • ChenH-I et al.

    Relationship between respiratory muscle function and age, sex, and other factors

    J Appl Physiol

    (1989)
  • RichardsonJ et al.

    Reproducibility of tests of respiratory muscle performance in chronic obstructive pulmonary disease

    Physiother Canada

    (1988)
  • Standardization of spirometry-1987 update

    Am Rev Respir Dis

    (1987)
  • SokalRR et al.

    Biometry

    (1981)
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    Manuscript received April 28; revision accepted January 7.

    Supported by a grant (NR01428) from the National Center for Nursing Research.

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