Biomaterial Database

Mechanisms of gas exchange abnormality in patients with chronic obliterative pulmonary vascular disease. 1979

D R Dantzker, and J S Bower

We have examined the mechanisms of abnormal gas exchange in seven patients with chronic obliteration of the pulmonary vascular bed secondary to recurrent pulmonary emboli or idiopathic pulmonary hypertension. All of the patients had a widened alveolar-arterial oxygen gradient and four were significantly hypoxemic with arterial partial presssures of oxygen less than 80 torr. Using the technique of multiple inert gas elimination, we found that ventilation-perfusion (VA/Q) relationships were only minimally abnormal with a mean of 10% (range, 2--19%) of cardiac output perfusing abnormal units. These units consisted of shunt and units with VA/Q ratios less than 0.1. In addition, the dead space was found to be normal in each patient. There was no evidence for diffusion impairment, and the widened alveolar-arterial oxygen gradient was completely explained by VA/ inequality. Significant hypoxemia occurred only when VA/Q inequality was combined with a low mixed venous oxygen content.

UI	MeSH Term	Description	Entries
D006976	Hypertension, Pulmonary	Increased VASCULAR RESISTANCE in the PULMONARY CIRCULATION, usually secondary to HEART DISEASES or LUNG DISEASES.	Pulmonary Hypertension
D008168	Lung	Either of the pair of organs occupying the cavity of the thorax that effect the aeration of the blood.	Lungs
D008176	Lung Volume Measurements	Measurement of the amount of air that the lungs may contain at various points in the respiratory cycle.	Lung Capacities,Lung Volumes,Capacity, Lung,Lung Capacity,Lung Volume,Lung Volume Measurement,Measurement, Lung Volume,Volume, Lung
D008297	Male		Males
D008875	Middle Aged	An adult aged 45 - 64 years.	Middle Age
D010100	Oxygen	An element with atomic symbol O, atomic number 8, and atomic weight [15.99903; 15.99977]. It is the most abundant element on earth and essential for respiration.	Dioxygen,Oxygen-16,Oxygen 16
D011652	Pulmonary Circulation	The circulation of the BLOOD through the LUNGS.	Pulmonary Blood Flow,Respiratory Circulation,Circulation, Pulmonary,Circulation, Respiratory,Blood Flow, Pulmonary,Flow, Pulmonary Blood,Pulmonary Blood Flows
D011655	Pulmonary Embolism	Blocking of the PULMONARY ARTERY or one of its branches by an EMBOLUS.	Pulmonary Thromboembolism,Thromboembolism, Pulmonary,Embolism, Pulmonary,Embolisms, Pulmonary,Pulmonary Embolisms,Pulmonary Thromboembolisms,Thromboembolisms, Pulmonary
D012119	Respiration	The act of breathing with the LUNGS, consisting of INHALATION, or the taking into the lungs of the ambient air, and of EXHALATION, or the expelling of the modified air which contains more CARBON DIOXIDE than the air taken in (Blakiston's Gould Medical Dictionary, 4th ed.). This does not include tissue respiration (	Breathing
D012126	Respiratory Dead Space	That part of the RESPIRATORY TRACT or the air within the respiratory tract that does not exchange OXYGEN and CARBON DIOXIDE with pulmonary capillary blood.	Dead Space, Respiratory,Dead Spaces, Respiratory,Respiratory Dead Spaces,Space, Respiratory Dead,Spaces, Respiratory Dead