Chest
Volume 116, Issue 5, November 1999, Pages 1377-1387
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Global Theme Issue: Emerging Technology in Clinical Medicine
Advances in Pulmonary Laboratory Testing

https://doi.org/10.1378/chest.116.5.1377Get rights and content

This review examines emerging technologies that are of potential use in the routine clinical pulmonary laboratory. These technologies include the following: the measurement of exercise tidal flow-volume (FV) loops plotted within the maximal FV envelope for assessment of ventilatory constraint during exercise; the use of negative expiratory pressures to asses expiratory flow limitation in various populations and under various conditions; the potential use of expired nitric oxide for assessing airway inflammation; and the use of forced oscillation for assessment of airway resistance. These methodologies have been used extensively in the research setting and are gaining increasing popularity and clinical application due to the availability of commercially available, simplified, and automated systems. An overview of each technique, its potential advantages and limitations will be discussed, along with suggestions for further investigation that is considered necessary prior to extensive clinical use.

Section snippets

Assessment of Ventilatory Limitation Using the extFVL

There has been a growing trend in both research and clinical laboratories to find alternative ways to evaluate ventilatory limitation during exercise.1, 2, 3, 4, 5 This stems in part from the realization that patients may discontinue exercise due to ventilatory constraints and dyspnea prior to the achievement of classic indexes associated with ventilatory limitation (ie, minute ventilation [

e] that reaches the maximum voluntary ventilation [MVV] or a rise in arterial CO2) and that
e limitation

Assessment of Expiratory Flow Limitation Using Negative Expiratory Pressures

Expiratory flow limitation promotes a dynamic increase in EELV with a concomitant increase in inspiratory work, impairment of inspiratory muscle function, and adverse effects on hemodynamics.19 These changes, combined with the dynamic compression of airways, likely contribute to dyspnea in patients with obstructive airway disease.11 The NEP technique evolved out of a need for an accurate assessment of expiratory flow limitation.20 It was originally used to assess expiratory flow limitation

Exhaled NO Measurement

NO is a highly reactive molecule formed by the enzyme NO synthase (NOS) from the precursor amino acid l-arginine. It was first described as an endogenous endothelium-derived nitrovasodilator that acts by directly activating guanylate cyclase, leading to increased cytosolic guanylate monophosphate by forming a reversible adduct with the heme moiety of the enzyme. Similarly, it may be readily inactivated by hemoglobin or cytochromes; thus, NO released into the blood stream is rapidly scavenged.

FO Resistance Measurement

Resistance to the movement of gas is calculated from the ratio of pressure change to flow. Resistance is of interest from both a basic science and a clinical perspective because it is an important determinant of the work of breathing (WOB). Total resistance of the respiratory system is a lumped sum of resistance to movement of lung tissue (Rti) and airway resistance (Raw) to the flow of gas. The sum of Rti and Raw for the lung is often called lung or pulmonary resistance. The measurement of Raw

References (64)

  • DD Marciniuk et al.

    Lung volumes and expiratory flow limitation during exercise in interstitial lung disease

    J Appl Physiol

    (1994)
  • DE O'Donnell et al.

    Measurement of symptoms, lung hyperinflation, and endurance during exercise in chronic obstructive pulmonary disease

    Am J Respir Crit Care Med

    (1998)
  • BD Johnson et al.

    Mechanical constraints on exercise hyperpnea in endurance athletes

    J Appl Physiol

    (1992)
  • R Hyatt

    The interrelationships of pressure, flow and volume during various respiratory maneuvers in normal and emphysematous subjects

    Am Rev Respir Dis

    (1961)
  • TG Babb et al.

    Effect of mild-to-moderate airflow limitation on exercise capacity

    J Appl Physiol

    (1991)
  • MJ Belman et al.

    Inhaled bronchodilators reduce dynamic hyperinflation during exercise in patients with chronic obstructive pulmonary disease

    Am J Respir Crit Care Med

    (1996)
  • M Younes et al.

    Respiratory mechanics and breathing pattern during and following maximal exercise

    J Appl Physiol

    (1984)
  • BD Johnson et al.

    Regulation of ventilatory capacity during exercise in asthmatics

    J Appl Physiol

    (1995)
  • B Johnson et al.

    Pulmonary mechanics during exercise in patients with chronic heart failure

    Eur Respir J

    (1998)
  • FJ Martinez et al.

    Lung mechanics and dyspnea after lung transplantation for chronic airflow obstruction

    Am J Respir Crit Care Med

    (1996)
  • FJ Martinez et al.

    Lung-volume reduction improves dyspnea, dynamic hyperinflation, and respiratory muscle function

    Am J Respir Crit Care Med

    (1997)
  • DE O'Donnell et al.

    Qualitative aspects of exertional breathlessness in chronic airflow limitation: pathophysiologic mechanisms

    Am J Respir Crit Care Med

    (1997)
  • M Chiba et al.

    Cardiopulmonary exercise testing in pseudoasthma associated with obesity

    Am J Respir Crit Care Med

    (1996)
  • D Murciano et al.

    Expiratory flow limitation in COPD patients after single lung transplantation

    Am J Respir Crit Care Med

    (1997)
  • P Valta et al.

    Detection of expiratory flow limitation during mechanical ventilation

    Am J Respir Crit Care Med

    (1994)
  • NG Koulouris et al.

    A simple method to detect expiratory flow limitation during spontaneous breathing

    Eur Respir J

    (1995)
  • C Braggion et al.

    Detection of tidal expiratory flow limitation in infants with cystic fibrosis: a pilot study

    Pediatr Pulmonol

    (1998)
  • J Boczkowski et al.

    Expiratory flow limitation in stable asthmatic patients during resting breathing

    Am J Respir Crit Care Med

    (1997)
  • NG Koulouris et al.

    Detection of expiratory flow limitation during exercise in COPD patients

    J Appl Physiol

    (1997)
  • RH Ingram et al.

    Effect of gas compression on pulmonary pressure, flow, and volume relationship

    J Appl Physiol

    (1966)
  • L Sette et al.

    Effect of pattern of preceding inspiration on FEV1 in asthmatic children

    Eur Respir J

    (1996)
  • NG Koulouris et al.

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

    Eur Respir J

    (1997)
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      Finally, we recall that the FVLs are easy to perform and acceptable even by naive individuals, and basically void of technical problems when using the new software and hardware. Typical examples in healthy subjects, and patients with COPD or CHF have been previously published.7–12,16,28 The results of the present study suggest that not only did the differences in the main cardiorespiratory functional parameters during exercise not reach any statistical significance, but they also remained well within the limits of natural variability reported in previous investigations.

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    This research was supported by National Heart Lung and Blood Institute Grant No. HL-52230 and Department of Health and Human Services grant No. M01RR00585.

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