2022年医学专题—Respiratory-Failure-呼吸衰竭(1).ppt

Respiratory Failure,第一页，共四十九页。,1.Abstracts,Respiratory failure,whether acute or chronic,is a frequently faced problem and a major cause of death in our country.For example,mortality from COPD,which ends in death from respiratory failure,continues to increase.More than 70%of the deaths in patients with pneumonia are attributed to respiratory failure.,第二页，共四十九页。,2.Definition,Respiratory failure is functional acute or chronic disorder caused by any condition that affects the lungs ability to maintain arterial oxygenation or carbon dioxide(CO2)elimination.It is defined as a condition in which this gas exchange deteriorates below the usual level,so that arterial oxygen tension decreases,with or without an abnormal rise in arterial carbon dioxide tension.,第三页，共四十九页。,3.Classifications,Generally both acute and chronic respiratory failure may be divided into two main categories:,第四页，共四十九页。,Type respiratory failure,Type respiratory failure is also called hypoxic respiratory failure,which means that severely reduces arterial oxygen tension(PaO260mmHg),CO2 retention is not exist.This type of respiratory failure is caused by a failure of gas exchange.,第五页，共四十九页。,Type respiratory failure,Type respiratory failure is also meant that hypercapnic-hypoxic respiratory failure.Arterial blood gas values shows that arterial carbon dioxide tension is more than 50 mmHg and arterial oxygen tension is less than 60 mmHgType respiratory is mainly caused by hypoventilation.,第六页，共四十九页。,Pathogenesis,Mainly discuss chronic respiratory failurewe have known that the lungs ability is gas exchange.The gas exchange involves not only oxygenation but also carbon dioxide elimination.,第七页，共四十九页。,Pathogenesis,Respiratory failure is mainly associated with pulmonary gas exchange and pulmonary ventilation.,第八页，共四十九页。,1.pulmonary gas exchange is mainly determined by ventilation-perfusion(V/Q)ratios and diffuse ability,V/Q mismatch:An effective lung gas exchange needs not only sufficient lung ventilation and lung blood volumes but also an adequate V/Q ratios.Usually,the volume of ventilation is 4 liters/min.The volume of lung blood is 5 liters/min.So the ratios is 0.8,第九页，共四十九页。,Any of the factors influenced the ratios may mainly cause hypoxemia respiratory failure.For example,V/Q0.8,including emphysema,pulmonary embolism.V/Q0.8,including atelectasis,severe COPD.,第十页，共四十九页。,Diffuse ability Diffusion abnormality mainly influence oxygen exchange.,第十一页，共四十九页。,2.Pulmonary hypoventilation,It may cause hypercapnic-hypoxic respiratory failure.Pulmonary hypoventilation includes restrictive hypoventilation and obstructive hypoventilation.Some diseases influenced central nervous system,peripheral nervous system,chest wall respiratory muscles and pulmonary compliance may all cause restrictive hypoventilation.,第十二页，共四十九页。,Some common conditions that may cause ventilatory failure with hypercapnea,These conditions include brain stem lesion,altered neuromuscular transmission(guillain-barre syndrome),muscle weakness(malnutrition,shock,hypoxemia,hypokalemia),increased airway resistance(upper airway obstruction,increased bronchial secretions and edema),decreased lung compliance(infection,atelectasis,interstitial fibrosis,acute lung injury),decreased chest wall compliance(chest wall trauma,pleural effusion,pneumothorax).,第十三页，共四十九页。,COPD and asthma are the most common disease associated to obstructive hypoventilation.In our clinical work,multifactors involve in the course of respiratory failure.For example,a COPD patient with severe pulmonary infection,his pulmonary gas exchange ability and pulmonary ventilation are all abnormal.,第十四页，共四十九页。,Pathophysiology,Hypoxia and hypercapnic may influence functions of many important organs and systems,including respiratory system,cardiovascular system,central nerve system,blood system and digestive system and renal function.,第十五页，共四十九页。,Clinical manifestations,Clinical signs include not only symptoms associated with primary diseases but also those caused by hypoxic and hypercapnic-hypoxic respiratory failure.Hypoxemia and hypercapnia mainly influence the function of important organs,including respiratory system,central nervous system,cardiovascular system,digestive system,renal functions.,第十六页，共四十九页。,The unbalance of acid-alkalose metabolic and dielectric abnormality are usually exist in the course of respiratory failure.Table 1.Clinical manifestations of hypoxia and hypercapnia.,第十七页，共四十九页。,Clinical manifestations of hypoxia and hypercapnia HYPOXEMIA HYPERCAPNIA Tachycardia Somnolence Tachypnea Lethargy Anxiety Restlessness Altered mental status Slurred speech Confusion Headache Cyanosis Asterixis Hypertension Papilledema Hypotension Coma Bradycardia Seizures Lactic acidosist,第十八页，共四十九页。,Diagnosis,According to history,clinical manifestations,physical examinations and blood gas analysis,we can diagnose respiratory failure.Especially arterial blood gas analysis may reveal hypoxemia and hypercapnia.,第十九页，共四十九页。,Diagnosis,The diagnosis