文档介绍：第十四章 肺功能不全 Chapter 14 Respiratory Failure
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概 述 General description
肺的正常功能及其评价指标；
呼吸衰竭的概念；
呼吸衰竭的ion
阻塞性通气不足
Obstructive hypoventilation
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（一）限制性通气不足 Restrictive hypoventilation
指呼吸动力减弱或胸廓和肺的扩张性能降低（弹性阻力增大）使肺泡扩张受限引起的通气功能障碍。
During inspiration, the dilation or inflation of alveoli are restricted.
It is caused by the diseases that affect the distensibility of the alveolar.
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①Paralysis of respiratory muscles
②Decreased compliance of chest wall
Causes of restrictive hypoventilation
③Decreased compliance of lung
④Hydrothorax or pneumothorax
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由于气道阻塞或狭窄,使气道阻力增加引起的通气障碍。
Obstructive hypoventilation is produced by airway constriction or obstruction.
（二）阻塞性通气不足 Obstructive hypoventilation
Central airway obstruction
Peripheral airway obstruction
trachea crotch
影响气道阻力的最主要因素是气道内径
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中央气道阻塞: Central airway obstruction
Extrathoracic airway
obstruction
Intrathoracic airway
obstruction
Expiration
Expiration
*吸气性呼吸困难
Inspiratory dyspnea
*呼气性呼吸困难Exspiratory dyspnea
Inspiration
Intra-airway pressure <
Atmospheric pressure
Intra-airway pressure >
Atmospheric pressure
Inspiration
Intra-airway pressure >
Intra-thoracic pressure
Intra-airway pressure <
Intra-thoracic pressure
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2. 外周气道阻塞 Peripheral airway obstruction
It refers to the airway obstruction at the bronchiole whose diameter is < 2mm.
Causes ：
慢性支气管炎 chronic bronchitis
支气管哮喘 bronchial asthma
慢性阻塞性肺气肿等 chronic obstructive emphysema ,etc.
（主要损害小气道）
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*呼气性呼吸困难
呼气时肺泡缩小，对小气道的牵拉作用减弱，胸内负压减小，气道内径变小，阻力增大，小气道狭窄更加明显；
吸气时反之，小气道狭窄减轻。
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肺气肿病人肺弹性回缩力降低，等压点也向肺泡端移动(上移)，易致小气道受压而闭合.
20
20
35
25
正常
肺气肿
等
压
点
20
20
20
30
20
10
0
0
5
10
20
20
20
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（三）全肺通气不足时的血气变化 Blood gas changes in hypoventilation
PAO2 = PiO2－
PACO2
R
R=
PACO2×VA
（PiO2-PAO2）×VA
Δ PaCO2↑
Δ PaO2↓
= R ≈
Alveolar
hypov