肺功能检查

定义

肺功能检查 are a group of tests that measure breathing 和 how well the lungs are functioning.

选择的名字

PFTs; Spirometry; Spirogram; Lung function tests; Lung volume; Plethysmography

如何执行测试

肺活量测定法测量气流. 通过测量你呼出的空气量, 还有你呼气的速度, spirometry can evaluate a broad range of lung diseases. 在肺活量测定中, 当你坐着时, you breathe into a mouthpiece 这是 connected to an instrument called a spirometer. The spirometer records the amount 和 the rate of air that you breathe in 和 out over a period of time. When st和ing, some numbers might be slightly different.

For some of the test measurements, you can breathe normally 和 quietly. Other tests require forced inhalation or exhalation after a deep breath. 有时, you will be asked to inhale a different gas or a medicine to see how it changes your test results.

肺体积测量有两种方法:

• The most accurate way is called body plethysmography. You sit in a clear airtight box that looks like a phone booth. The technologist asks you to breathe in 和 out of a mouthpiece. Changes in pressure inside the box help determine the lung volume.
• Lung volume can also be measured when you breathe nitrogen or helium gas through a tube for a certain period of time. The concentration of the gas in a chamber attached to the tube is measured to estimate the lung volume.

来衡量 扩散能力, you breathe a harmless gas, called a tracer gas, for a very short time, often for only one breath. The concentration of the gas in the air you breathe out is measured. The difference in the amount of gas inhaled 和 exhaled measures how effectively gas travels from the lungs into the blood. This test allows the health care provider to estimate how well the lungs move oxygen from the air into the bloodstream.

如何准备考试

考试前不要吃太多. 测试前4 - 6小时不要吸烟. You will get specific instructions if you need to stop using bronchodilators or other inhaled medicines. You may have to breathe in medicine before or during the test.

考试的感觉如何

Since the test involves some forced breathing 和 rapid breathing, you may have some temporary 呼吸急促（气促） or lightheadedness. 你可能还会咳嗽. You breathe through a tight-fitting mouthpiece 和 you will have nose clips. If you are claustrophobic, the part of the test in the closed booth may feel uncomfortable.

Follow instructions for using the mouthpiece of the spirometer. A poor seal around the mouthpiece may cause results that aren't accurate.

为什么要进行测试

肺功能检查的目的是:

• Help in the diagnosis of certain types of lung disease, such as 哮喘, 支气管炎, 肺气肿
• 找出原因 呼吸急促（气促）
• Measure whether exposure to chemicals at work affects lung function
• 手术前检查肺功能
• 评估药物的效果
• 衡量疾病治疗的进展
• Measure the response to treatment in cardiopulmonary vascular disease

正常的结果

Normal values are based on your age, height, ethnicity, sex. 正常结果以百分比表示. A value is usually considered abnormal if it is approximately less than 80% of your predicted value.

Normal value ranges may vary slightly among different laboratories, based on slightly different ways to determine normal values. Talk to your provider about the meaning of your specific test results.

Different measurements that may be found on your report after pulmonary function tests commonly include:

• 一氧化碳扩散能力(DLCO)
• 呼气储备量(ERV)
• 肺活量(FVC)
• 1秒用力呼气量(FEV1)
• 用力呼气流量25% ~ 75% (FEF25-75)
• 功能剩余容量(FRC)
• 最大自主通气(MVV)
• 剩余容积(RV)
• 最大呼气流量(PEF)
• 慢肺活量(SVC)
• 总肺容量(TLC)

异常结果意味着什么

Abnormal results usually mean that you may have chest or lung disease.

一些肺部疾病(如肺气肿), 哮喘, 慢性支气管炎, infections) can make the lungs contain too much air 和 take longer to empty. These lung diseases are called obstructive lung disorders.

Other lung diseases make the lungs scarred 和 smaller so that they contain too little air 和 are poor at transferring oxygen into the blood. 这类疾病的例子包括:

• 极端的超重
• Pulmonary fibrosis (scarring or thickening of the lung tissue)
• 结节病 和 硬皮病

Muscular weakness can also cause abnormal test results, 即使肺部是正常的, 这是, 类似于导致肺变小的疾病.

风险

有一个小的风险 肺功能衰竭, (pneumothorax) in people with a certain type of lung disease. The test should not be given to a person who has experienced a recent heart attack, 还有其他类型的心脏病吗, 或者最近有肺萎陷.

参考文献

Bhakta NR, Kaminsky DA. Pulmonary function testing: physiologic 和 testing principles. 见:broadus VC, Ernst JD, King TE等编. Murray 和 Nadel's Textbook of Respiratory Medicine. 7日艾德. Philadelphia, PA: Elsevier; 2021:chap 31.

斯坎伦PD. 呼吸功能:机制和测试. 参见:Goldman L, Schafer AI主编. Goldman-Cecil医学. 26日艾德. Philadelphia, PA: Elsevier; 2020:chap 79.

Wald O, Izhar U, Sugarbaker DJ. 肺，胸壁，胸膜和纵隔. In: Townsend CM Jr, Beauchamp RD, Evers BM, Mattox KL, eds. 萨比斯顿外科教科书. 21艾德. Philadelphia, PA: Elsevier; 2022:chap 58.