Chapter 033. Dyspnea and Pulmonary Edema (Part 2) Integration: Efferent-Reafferent Mismatch A discrepancy or mismatch between the feed-forward message to the ventilatory muscles and the feedback from receptors that monitor the response of the ventilatory pump increases the intensity of dyspnea. This is particularly important when there is a mechanical derangement of the ventilatory pump, such as in asthma or chronic obstructive pulmonary disease (COPD). Anxiety Acute anxiety may increase the severity of dyspnea either by altering the interpretation of sensory data or by leading to patterns of breathing that heighten physiologic abnormalities in the respiratory system. In patients with expiratory flow limitation, for example, the increased respiratory rate that accompanies acute anxiety leads to hyperinflation, increased work of breathing, a sense of an increased effort to breathe, and a sense of an unsatisfying breath. Assessing Dyspnea Quality of Sensation As with pain, dyspnea assessment begins with a determination of the quality of the discomfort (Table 33-1). Dyspnea questionnaires, or lists of phrases commonly used by patients, assist those who have difficulty describing their breathing sensations. Table 33-1 Association of Qualitative Descriptors and Pathophysiologic Mechanisms of Shortness of Breath Descriptor Pathophysiology Chest tightness or constriction Bronchoconstriction, interstitial edema (asthma, myocardial ischemia) Increased work or effort of breathing Airway obstruction, neuromuscul ar disease (COPD, moderate to severe asthma, myopathy, kyphoscoliosis) Air hunger, need to breathe, urge to breathe Increased drive to breathe (CHF, pulmonary embolism, moderate to severe airflow obstruction) Cannot get a deep breath, unsatisfying breath Hyperinflation (asthma, COPD) and restricted tidal volume (pulmonary fibrosis, chest wall restriction) Heavy breathing, rapid breathing, breathing more Deconditioning Note: CHF, congestive heart failure; COPD, chronic obstructive pulmonary disease. Source: From Schwartzstein and Feller-Kopman. Sensory Intensity A modified Borg scale or visual analogue scale can be utilized to measure dyspnea at rest, immediately following exercise, or on recall of a reproducible physical task, e.g., climbing the stairs at home. An alternative approach is to inquire about the activities a patient can do, i.e., to gain a sense of the patient's disability. The Baseline Dyspnea Index and the Chronic Respiratory Disease Questionnaire are commonly used tools for this purpose. Affective Dimension For a sensation to be reported as a symptom, it must be perceived as unpleasant and interpreted as abnormal. We are still in the early stages of learning the best ways to assess the affective dimension of dyspnea. Some therapies for dyspnea, such as pulmonary rehabilitation, may reduce breathing discomfort, in part, by altering this dimension. . Chapter 033. Dyspnea and Pulmonary Edema (Part 2) Integration: Efferent-Reafferent Mismatch A discrepancy or mismatch between the feed-forward message to the ventilatory muscles and. unpleasant and interpreted as abnormal. We are still in the early stages of learning the best ways to assess the affective dimension of dyspnea. Some therapies for dyspnea, such as pulmonary. breathe (CHF, pulmonary embolism, moderate to severe airflow obstruction) Cannot get a deep breath, unsatisfying breath Hyperinflation (asthma, COPD) and restricted tidal volume (pulmonary