1、Respiratory Failure 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 pneumoni
2、a are attributed to respiratory failure.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 deteriora
3、tes below the usual level,so that arterial oxygen tension decreases,with or without an abnormal rise in arterial carbon dioxide tension.3.Classifications Generally both acute and chronic respiratory failure may be divided into two main categories:Type respiratory failure Type respiratory failure is
4、also called hypoxic respiratory failure,which means that severely reduces arterial oxygen tension(PaO20.8,including emphysema,pulmonary embolism.V/Q0.8,including atelectasis,severe COPD.Diffuse ability Diffusion abnormality mainly influence oxygen exchange.2.Pulmonary hypoventilation It may cause hy
5、percapnic-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 hypoventila
6、tion.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,increa
7、sed bronchial secretions and edema),decreased lung compliance(infection,atelectasis,interstitial fibrosis,acute lung injury),decreased chest wall compliance(chest wall trauma,pleural effusion,pneumothorax).COPD and asthma are the most common disease associated to obstructive hypoventilation.In our c
8、linical 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.Pathophysiology Hypoxia and hypercapnic may influence functions of many important organs and
9、 systems,including respiratory system,cardiovascular system,central nerve system,blood system and digestive system and renal function.Clinical manifestations Clinical signs include not only symptoms associated with primary diseases but also those caused by hypoxic and hypercapnic-hypoxic respiratory
10、 failure.Hypoxemia and hypercapnia mainly influence the function of important organs,including respiratory system,central nervous system,cardiovascular system,digestive system,renal functions.The unbalance of acid-alkalose metabolic and dielectric abnormality are usually exist in the course of respi
11、ratory failure.Table 1.Clinical manifestations of hypoxia and hypercapnia.Clinical manifestations of hypoxia and hypercapnia HYPOXEMIA HYPERCAPNIA Tachycardia Somnolence Tachypnea Lethargy Anxiety Restlessness Altered mental status Slurred speech Confusion Headache Cyanosis Asterixis Hypertension Pa
12、pilledema Hypotension Coma Bradycardia Seizures Lactic acidosist 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.Diagnosis The diagnosis
13、 standard include:Type respiratory failure:PaO2 50mmHg,PaO2 60mmHg.In the condition of oxygen therapy,PaO2/Fi O270-80mmHg 2.severe hypoxemia,after oxygen therapy,PaO235 per minute or severe breathlessness 4.severe metabolic acidosis or pulmonary encephalopathy (2)Antiinfectious therapy Repeated bron
14、chial and pulmonary infection is a major cause of chronic respiratory failure.About 90%of COPD patients with respiratory failure is caused by acute bronchial or pulmonary infection.Infection may also increase bronchial secretion and CO2 production.So antiinfectious therapy is an important method to
15、treat respiratory failure.Select effective antibiotics According to sputum culture,we can select sensitive antibiotics Using combined antibiotics Because of multibacteria infection,it needs several kind of antibiotics.For example,we may combine second or third generation cephalosporin to aminoglycos
16、ide or fluoroguinolone.(3)Oxygen therapy The goal of oxygen therapy is to improve PaO2.It makes PaO260%.In general,the lowest FiO2 achieving adequate oxygenation.sometimes,arterial oxygen saturation90%should be used.The methods of oxygen therapy:nasal prongs 1-3L/min to chronic respiratory failure venti mask 1-3L/min For type 1 respiratory failure,we can elevate the percentage of oxygen to maintain the PaO2.We can use higher inspirated fration of oxygen in type 1 respiratory failure oxygen thera