Functional residual capacity (FRC)

Functional residual capacity (FRC) calms the amount of gas remaining in the lungs after exhalation. FRC = RC + ERV. FRC physiologically acts as a buffer for stabilizing the partial pressure of alveolar gas, reducing the effect of intermittent ventilation on gas exchange in the alveoli. If there is no FRC, the end-expiratory alveoli will completely collapse. An increase in FRC suggests an alveolar dilatation, and a decrease in FRC indicates a reduction or collapse of the alveoli. Basic Information Specialist classification: Respiratory examination classification: pulmonary function test Applicable gender: whether men and women apply fasting: not fasting Tips: Two days before the examination, all the drugs for bronchiectasis should be stopped, such as Shuchuanling, Bangfu, Meipuqing, aminophylline, Shufumei Lehui, Asami, Aichuan, etc. Otherwise it will affect the inspection result. Normal value Male 2.27 ± 0.81L; female 1.86 ± 0.55L. Clinical significance Abnormal results: 1, reduce pulmonary fibrosis, after lung resection and so on. 2, increase emphysema, small airway premature closure. Residual gas volume increased significantly, suggesting chronic obstructive ventilatory disorders, such as emphysema, pulmonary heart disease. Need to check the crowd: Pulmonary dysfunction such as difficulty breathing, or an auxiliary diagnosis of lung disease. Low results may be diseases: high results of pulmonary heart disease may be diseases: pulmonary fibrosis, obstructive emphysema, emphysema precautions Preparation before inspection: Two days before the examination, all the drugs for bronchodilation should be stopped, such as Shuchuanling, Bangfu, Meipuqing, aminophylline, Shufumei Lehui, Asami, Aichuan, etc., otherwise it will affect test result. Note when checking: 1 Because the nose is caught, you should learn to breathe with your mouth. 2 As close as possible to the mouth, to ensure that there will be no air leakage during the test. 3 As much as possible with the doctor's password, instant exhalation and inhalation. 4 Do your best to inhale, then use your doctor to exhale with maximum strength, and don't have to keep your strength. Inspection process Inspection method: The volume of gas entering and leaving the lungs per unit time with respiratory movement is measured by a spirometer, which can reflect changes in lung capacity, airway patency, and integrity of thoracic and respiratory muscle functions. This detection method is simple and easy to repeat. Not suitable for the crowd Not suitable for people with pulmonary function tests: 1 severe airflow limitation (FEV1 <50% predicted value or <1.0L). 2 There is a heart attack or shock in the past 3 months. 3 uncontrolled hypertensive patients (systolic blood pressure > 200 or diastolic blood pressure > 100). 4 known patients with aortic aneurysm. 5 pregnancy. 6 lactation period. 7 people who have been exposed to specific antigens within the first week. 8 can not cooperate with the doctor to perform quality lung function testers. 9 currently using choline enzyme inhibitory drugs (myasthenia gravis). 10 Patients with upper or lower respiratory tract infection within 6 weeks before the test. Adverse reactions and risks Generally no complications and harm.

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