Respiratory Failure (1).ppt PDF

Respiratory failure  (hū)(xī)(gōng)(néng)(bù)(quán) 吸功能不全 respiratory insufficiency ） complete compensation incomplete compensation decompensated period (hū)(xī)(shuāi)(jié) 呼吸衰竭 （ respirator y failure ） decompensation  Respiratory Insufficiency 呼吸...

Respiratory failure  (hū)(xī)(gōng)(néng)(bù)(quán) 吸功能不全 respiratory insufficiency ） complete compensation incomplete compensation decompensated period (hū)(xī)(shuāi)(jié) 呼吸衰竭 （ respirator y failure ） decompensation  Respiratory Insufficiency 呼吸功能不全 A condition in which external respiratory disturbance alters homeostasis, affecting blood gas results, but not to reach the extent of respiratory failure. Arterial blood gas is normal under resting condition but is abnormal at enhanced sports load.  呼吸衰竭 Respiratory A Failure condition in which PaO2 decreased with or without PaCO2 increased in the setting of excluding intracardiac disturbed external respiration. right-to-left shunts, PaO250mmHg decrease  60mmHg oxygen dissociation  Categories 1.+ PaCO2 normal PaO TypeⅠ: 2hypoxemic TypeⅠ: hypoxemic respiratory failure PaO +2 PaCO2 Type Ⅱ: hypercapnic respiratory failure ventilatory + gas exchange (pathogenesis) + peripheral (primary s.central + chronic (disease course.acute etiology and pathogenesis Respiratory failure external respiration PaO< 2 60mmHg dysfunction With or without > PaCO 50mmHg 2 nervous system wholesome respiratory muscles whole thoracic cage unobstructed air passages normal alveoli thorough pulmonary circulation oventilation Diffusion abnormaliti PO2 Anatomic shunt tilation-perfusion mismatch oventilation Restrictive Obstructive  Diffusion abnormaliti eolar-capillary membrane area ar-capillary membrane thicken oventilation Anatomic shunt tilation-perfusion mismatch poventilation to functional shun operfusion to dead space-like ven  12.1 The Etiology and pathogenesis poventilation Restrictive hypoventilation Obstructive hypoventilation fusion abnormalities eolar-capillary membrane area ar-capillary membrane thicken lation-perfusion mismatc hypoventilation to functional sh operfusion to dead space-like ven natomic shunt Hypoventilation monary ventilation volume = 6 L/min olar ventilation =volume 4 L/min ead space volume = 2 L/min = 70 L/min obvious ventilation disorders lead to respiratory failure Restrictive hypoventilatio Alveolar expansion is limited in inspiration, then causes alveolar ventilation Elastic insufficiency. resistance Lung volumes are determined by the mechanical properties of the lungs,chest wall and by the force generated by the respiratory muscles overcoming the recoil characteristics expirati inspirat on ion sternocleidom stoids scalene interna s l external interco interco stals stals abdomin diaphra al m Visceral Parietal pleura pleura Chest Diaphra wall rictive hypoventilation orders of respiratory mu sorders sorders of the chest wal isorders Disorders of pleura Disorders of lungs rders of respiratory musc 1.diseases affecting respiratory centers ;(poliomyelitis) central nervous system depression by anesthetic, sedative  2.respiratory muscle function disorders respiratory muscle fatigue, atrophy ['ætrəfɪ] asthenia gravis maɪəs'θiːnɪə] Both the lungs and chest wall are distensible structure with elastic properties which generate Elastic resistance. Restrictive hypoventilation can be caused by disease affecting the distensibility of lungs or chest wall  orders of the chest wall malformation Ankylosing Spondylitis thoracoplasty[,æŋki'ləuziŋ,spɔndi'laitis] scoliosis sorders of lungs 1)decreased volume ： pneumonectomy [,njuːmə(ʊ)'nektəmɪ] pulmonary atelecta isorders of lungs obar pneumonia inflammatory seep sorders of lungs 2).increased stiffness(decreased distensibility) silicosis isorders of lungs 3)decreased surface active material pulmonary ate lectasis sorders of pleura Pneumothorax hydrothorax rictive hypoventilation orders of respiratory mus sorders of the chest wall isorders of pleura isorders of lungs  12.1 The Etiology and pathogenesis poventilation Restrictive hypoventilation Obstructive hypoventilation fusion abnormalities eolar-capillary membrane area ar-capillary membrane thicken lation-perfusion mismatc hypoventilation to functional functiona perfusion to dead space-like vent natomic shunt structive hypoventilation Obstructive hypoventilation refers to ventilatory dysfunction induced by airway narrowing or Non-elastic obstruction. resistance Non-elastic resistance inertial resistance viscous resistance Airway resistance: 80- 90%  Poiseuil le ’s law Airway length × gas viscosity π×airway radius4or5 R=8ηL/ πr 4 R=8ηL/πr5 Intraluminal diameter  R=8ηL/ πr 4 Small peripheral pulmonary airways tal area:（100 diameter80%R 2 ① wall of trachea shrink or thickening Asthma, chronic bronchitis ② lumen block: foreign matter ③ external compression pulmonary elastic stretch tructive hypoventilatio (1) Central airway obstruction above the tracheal bifurcation 2) Peripheral Without cartilage, when distraction is weakened, easily tructive hypoventilatio entral airway obstructio trathoracic ： inspiratory trathoracic ： expiratory 2) Peripheral xpiratory dyspnea entral airway obstructio athoracic obstruction piratory dyspnea expirati on ： atmospheric pressure < tracheal pressure inspir ation ： atmospheric pressure > tracheal pressure athoracic obstruction pleural pressure tracheal pressure athoracic obstruction expirati on ： pleural pressure > tracheal pressure inspir ation ： pleural pressure tracheal pressure athoracic obstruction atory dyspnea expirati on ： pleural pressure > tracheal pressure inspir ation ： pleural pressure < tracheal pressure tructive hypoventilatio entral airway obstructio trathoracic ： inspiratory trathoracic ： expiratory 2) Peripheral xpiratory dyspnea eripheral airway obstruct expiratory dyspnea expirati on ： pleural pressure > tracheal pressure inspir ation ： pleural pressure < tracheal pressure eripheral airway obstruct expiratory dyspnea downstr eam Equal press ure point forced expiration can cause upstre small airway closure am tructive hypoventilatio entral airway obstructio trathoracic ： inspiratory trathoracic ： expiratory 2) Peripheral xpiratory dyspnea  12.1.2 Blood gas changes in alveolar In alveoli ： O2 CO2 hypoventilation PAO2 In P blood ACO 2 ： P aO 2 PaCO Type Ⅱ: 2hypercapnic respiratory failure  Gas-exchange abnormalities.Diffusion Abnormalitie What are the factors that influence the gas diffusion thickness capacity? area speed of gas  Diffusion Abnormali P1 – P 2 Vgas ≈ A × D × T Pressure gradient directly propotional Thickness inversely propotional O Area 2 ed of gas CO2 ffusion constant) CO2:02=20:1 Solubility 24 Diffusion Abnormalities P1 – P 2 Vgas ≈ A × D× T thickness area ed cell stay time fusion Abnormalities 1.area 80 m < 40 m 2 2 Atelectasis [,ætɪ'lektəsɪs] bullae of lung Pneumonectomy [,njuːmə(ʊ)'nektəmɪ].thickness 1 μm air-blood barrier O2 gas exchange CO2 is fast 5 μm  Hyaline membrane thickness disease, HMD respiratory distress syndrome, RDS Fibrosis pulmonary.thickness 1 μm Shortening in the Diffusion Time 0.75s >0.25s ed cellO2 uptake 5 μm equilibrates pO2 （ kP a） 13.3 正常 10.7 8.00 肺泡膜增厚 5.33 （2 ） （1 2.67 肺动脉 肺泡毛细血管） 肺静脉 0 0 0.25 0.50 时间0.75 （S） 正常与肺泡膜增厚时 Hb 氧合所需时间示意图 （ 1 ）静息时血液流经肺泡的时间 （ 2 ）运动时血液流经肺泡的时间  12.1.2.2 Blood gas changes in diffusion Paabmormalities O2 PaCO Norma 2 l or CO2 diffuse through 20 times more rapidly than oxygen because of its high solubility TypeⅠ: hypoxemic respiratory failure  12.1 The Etiology and pathogenesis poventilation Restrictive hypoventilation Obstructive hypoventilation fusion abnormalities eolar-capillary membrane area ar-capillary membrane thicken lation-perfusion mismatc hypoventilation to functional sh operfusion to dead space-like ven natomic shunt tilation-perfusion imba Most important and common mechanism of respiratory failure caused by lung disease. oventilation Anatomic shunt tilation-perfusion mismatch poventilation to functional shun operfusion to dead space-like ven lation-perfusion mismatchin norm PaO2< PAO2 al V=0.5 Q=0. 1.0 21.0 2.5 3.8 V=4.0L/min =0.8 Q=5L/ min.Local hypoventilation V/Q 0.8 0. nctional dead space 8 VD/VT 2/6 30% 60-70%  血流 cal hypoperfusion 不足 病肺 健肺 全肺.. VA/Q>0.8 0.8 80  12.2The alteration of function and metabolism Disturbances of acid-base and electrolytes espiratory disturbances irculatory disturbances tbances of central nervous Renal failure Alimentary tract