Dyspnea Jung Hyun Chang, M.D. Department of Respiratory Medicine Ewha Womans University College of Medicine, Mokdong Hospital E mail : hs1017@ewha.ac.kr Abstract Dyspnea is one of the most common respiratory symptoms and is a term to indicate a subjective experience of breathing discomfort. Most patients with dyspnea can be categorized into two groups: respiratory system dyspnea and cardiovascular system dyspnea. The underlying mechanisms encompass variable interactions of physiological, psychological, social, and environmental factors. Among these physiologic mechanisms are most important. Respiratory system dyspnea derives from stimulation of central or peripheral chemoreceptor, stimulation of mechanoreceptor, motor commands of cerebral cortex, afferent mismatch and/or neuromechanical dissociation due to derangements in the central controller, the ventilatory pump, and gas exchanger. Cardiovascular system dyspnea derives from impaired oxygen delivery and oxygen utilization due to cardiac disease, anemia, and deconditioning. The objective scales and standardized measurements for the subjective expression of dyspnea have been commonly used. The proper evaluation and treatment of dyspnea have to be planned taking underlying diseases and accompanying physiologic mechanisms into consideration. Keywords : Dyspnea; Respiratory; Cardiovascular; Physiological; Chemoreceptor 254
Efferent signals Afferent signals Motor cortex Effort() Sensory cortex Chemoreceptors Effort Air hunger Brainstem( ) Upper airway Upper airway Chest tightness Ventilatory muscles (9) 255
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Borg Medical Research Council Rating Intensity of sensation Grade 1 Breathless with strenuous exercise 0 Nothing at all Grade 2 Short of breath when hurrying on the level or walking 0.5 Very, very slight (just noticeable) up a slight hill 1 Very slight Grade 3 Walk slower than people of the same age on the 2 Slight level or stop for breath while walking at own pave 3 Moderate on the level 4 Somewhat severe Grade 4 Stop for breath after walking about 100 yards or 5 Severe after a few minutes on the level 6 Grade 5 Too breathless to leave the house or breathless 7 Very severe when dressing or undressing 8 9 Very, very severe (almost maximal) 10 Maximal 260
Descriptions Grade Degree Not troubled by shortness of breath when hurrying on the level or walking up a slight hill Troubled by shortness of breath when hurrying on the level or walking up a slight hill Walks more slowly than people of the same age on the level because of breathlessness or has to stop for breath when walking at own pace on the level Stops for breath after walking about 100 yard or after a few minutes on the level Too breathless to leave the house; breathless on dressing or undressing 0 1 2 3 4 None Mild Moderate Severe Very severe 261
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