Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0020440 (hypercapnia)
 7,939 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Any factor that inhibits the ability of an individual with asthma to recognize their symptoms appropriately may contribute to treatment delay, "near miss" events, and death during acute severe asthma. The purpose of this study was to investigate the effects of two common features of acute severe asthma--hypoxia and hypercapnia--on respiratory sensation. Sixteen individuals with stable asthma were exposed to three gas conditions (34 minutes each): isocapnic hypoxia (arterial blood O2 saturation of approximately 80%), hypercapnia (increase in end-tidal CO2 of approximately 5-10 Torr), or isocapnic normoxia on 3 separate days. The perceived magnitude of externally applied resistive loads, measured during each gas condition, was reduced throughout hypoxia compared with normoxia, and there was a trend for a progressive decline during hypercapnia. Within the 15-minutes postgas inhalation period, methacholine-induced symptoms of difficult breathing, chest tightness, and breathlessness, measured using modified Borg scales, were 25-30% lower after hypoxia compared with normoxia but were not reduced after hypercapnia. We conclude that 30 minutes of sustained hypoxia and possibly hypercapnia impair sensations of respiratory load and that the effects of hypoxia persist for at least 10 minutes after returning to normoxia.
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PMID:Hypoxia suppresses symptom perception in asthma. 1502 Feb 91

Dyspnea is the unpleasant awareness of breathing while healthy persons will hardly sense their own breath at rest. Dyspnea is comparable to pain because both caution the organism that will activate protective mechanisms to avoid further damage. Dyspnea results from central nervous processing of respiratory feed back signals. Feed back from respiratory muscles, the chest wall, the airways and the lung reach the brain while partial pressure of oxygen and carbon dioxide is continuously monitored and arterial blood gases are permanently stabilized. Sensation of breathlessness depends on its origin. Main qualities of dyspnea include air hunger during hypercapnia, laboured breathing during increased minute ventilation and chest tightness in asthma. During chronic dyspnea, respiratory control aims for a new breathing pattern that will ease breathlessness. Since respiratory control includes both autonomic regulation and cortical modulation of breathing, voluntarily guided respiration can be employed to influence other autonomic regulated systems and pain perception.
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PMID:[Breathlessness: different causes and qualities of dyspnea]. 1955 55