Guidelines for mechanical lung function measurements in psychophysiology

Abstract

Studies in psychophysiology and behavioral medicine have uncovered associations among psychological processes, behavior, and lung function. However, methodological issues specific to the measurement of mechanical lung function have rarely been discussed. This report presents an overview of the physiology, techniques, and experimental methods of mechanical lung function measurements relevant to this research context. Techniques to measure lung volumes, airflow, airway resistance, respiratory resistance, and airflow perception are introduced and discussed. Confounding factors such as ventilation, medication, environmental factors, physical activity, and instructional and experimenter effects are outlined, and issues specific to children and clinical groups are discussed. Recommendations are presented to increase the degree of standardization in the research application and publication of mechanical lung function measurements in psychophysiology.Descriptors: Mechanical lung function, Airway resistance, Respiratory resistance, Spirometry, Pneumotachography, Body plethysmography, Forced oscillation technique, Interrupter technique, Respiratory perception Despite long-standing interest in respiration by psychophysiologists, it is surprising that little attention has been directed to methodological issues of specific measurement techniques in this area. Although occasional textbook chapters have been devoted to respiration measurements, a more in-depth discussion of techniques dealing with the assessment of mechanical lung function is still missing. Mechanical lung function relates to lung volumes and airflow through the respiratory system as well as the pressurevolume and pressure-flow characteristics as indicators of elastic and resistive properties of the airways, lungs, and chest wall. In clinical practice, mechanical lung function measures are widely used for the diagnosis and management of various pulmonary diseases, most importantly bronchial asthma and chronic obstructive pulmonary disease~COPD!. In psychophysiology and behavioral medicine, potential associations between psychological or behavioral processes and mechanical lung function offer an exciting perspective both for basic research and clinical application. Due to the particular importance of the vagal system in governing airway function, the airways offer a unique window into the autonomic nervous system regulation of behavior, emotion, and cogThomas Ritz acted as coordinator and contributor to this report. The authorship of the other contributors was determined by alphabetical order. Different sections were drafted by individual contributors, submitted to internal peer review, and revised until consensus was achieved. We are indebted to

Targeting pCO2 in Asthma: Pilot Evaluation of a Capnometry-Assisted Breathing Training

“…At follow-up, in addition to reduction in symptoms and greater asthma control through questionnaires, two patients also reported that they felt improvements in their ability to control symptoms and to recover from asthma exacerbation. Although spirometric indices of lung function are typically dependent on PCO2 Biofeedback in Asthma 17 patients' effort (Ritz et al, 2002), we do not think that the observed reductions in PEF variability could easily be explained by this factor. Complicated and less plausible assumptions would have to be invoked to explain this finding, such as a reduction in the inconsistency in patients' effort due to therapy.…”

“…Lung function remained stable, although decreases were seen in respiratory resistance that might have been significant with a larger sample size. A greater sensitivity of these more direct measures of airway obstruction to the effects psychosocial interventions has been observed before (Lehrer, Vaschillo, Vaschillo, et al, 2004;Ritz, Dahme, DuBois, et al, 2002).…”

“…These measurements were taken initially at each of the five training sessions by an investigator who did not conduct the sessions. This measure of respiratory resistance has the advantage of being effort-independent and provides a more direct index of airway constriction (Ritz et al, 2002). Before and after the 4-week treatment and at follow-up, patients recorded their PEF five times daily: in the morning after awakening (before bronchodilator), and at approximately 11am, 2 pm, 5 pm, and 8 pm.…”

The resistance of the respiratory system, from top to bottom

“…This method (see e.g. [19]) is based on a sudden interruption of airflow during spontaneous breathing. It is considered that during a short time after the interruption, the pressure at the mouth balances with the alveolar pressure P a .…”

“…The first attempt to quantify this phenomenon by a single parameter was proposed a century ago by Fritz Rohrer [20], and since then it has been used intensively in the context of medical practice, or mathematical modeling (see e.g. [1,9,13,19]). …”