1 / 73

Respiratory Failure

Respiratory Failure. Zhang Xiao-ming Dept. pathophysiology. 男性 , 50 岁 , 患喘息性支气管炎 30 年 , 三年来常下肢浮肿 . 三天前因受凉发烧 , 咳嗽加重 , 咳黄痰 . 当日上午患者神志恍惚 , 嗜睡 . 查 : T 38℃, 颈静脉充盈 , 肝大 , 双下肢凹陷性水肿 . 血气分析 : pH7.29, PaCO 2 10.7kPa(80mmHg), PaO 2 7.33kPa(55mmHg). BE -5mmol/L 血清钾 5.5mmol/L. RESPIRATION

emerson
Download Presentation

Respiratory Failure

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Respiratory Failure Zhang Xiao-ming Dept. pathophysiology

  2. 男性, 50岁, 患喘息性支气管炎30年, 三年来常下肢浮肿. 三天前因受凉发烧, 咳嗽加重, 咳黄痰. 当日上午患者神志恍惚, 嗜睡. 查: T 38℃, 颈静脉充盈, 肝大, 双下肢凹陷性水肿. 血气分析: pH7.29, PaCO2 10.7kPa(80mmHg), PaO2 7.33kPa(55mmHg). BE -5mmol/L血清钾 5.5mmol/L.

  3. RESPIRATION 4 distinct mechanisms: Ventilation Gas exchangeExternal respiration Transportof oxygen and carbon dioxide in the blood Internal respiration

  4. The Process of External Respiration PiO2 159mmHg Pulmonary ventilation PAO2 102mmHg PACO2 40mmHg Pulmonary gas exchange PaO240mmHg PaCO2 46mmHg PvO2 100mmHg PvCO2 40mmHg

  5. Definition of RF Disorders of external respiratory function PaO2 <60 mmHg (8.0kpa) while breathing air at rest, with or withoutPaCO2 >50 mmHg(6.67kpa). judgment standard: PaO2 <60 mmHg , PaCO2 >50 mmHg hypotonic hypoxia with (or without) respiratory acidosis

  6. respiratory insufficiency: It is a condition in which respiratory function is inadequate to meet body’s needs during exertion. However, respiratory failure does so in rest. a kind of respiratory insufficiency a severe respiratory insufficiency

  7. Classification 1. According to blood gas: 1) typeⅠ(hypoxemic RF) : PaO2 <60 mmHg (8.0kpa) 2) type Ⅱ (hypercapnic RF) : PaO2 <60 mmHg (8.0kpa) , with PaCO2 >50 mmHg(6.67kpa)

  8. 2. According to primary site central peripheral 3. According to duration acute chronic

  9. Section 1 Causes and pathogenesis of respiratory failure

  10. Pathogenesis of RF: Disorders of external respiratory functionpulmonary ventilation disturbance pulmonary gas exchange disturbance

  11. Ⅰ.pulmonary ventilation disturbance i.Types and Causes restrictive hypoventilation obstructive hypoventilation

  12. Causes of RF Disorders of: Central Nervous System Spinal Cord Neuromuscular System the chest wall and pleura the airway

  13. component elements causing ventilation disturbance Airway straitness or block thorax wall damaged Inhibition of R. center High spinal cord damaged weakness of R. M Anterior angle cell damaged phrenic nerve damaged Lung elastic resistance increased

  14. Restrictive hypoventilation: Causes and mechanisms: • impaired activity of respiratory muscle (dysfunction of CNS, neural, muscleetc.) • decreased compliance of thorax (chest malformation , pleura fibrosis) • decreased compliance of lungs (pulmonary edema , inflammation , fibrosis, insufficient surfactant) • thorax fluidify or pneumothorax

  15. 2. Obstructive hypoventilation : central airway obstruction peripheral airway obstruction

  16. 1) central airway obstruction: above the forfication (between the glottis and the carina) obstruction locates out of thorax( paralysis, edemaor inflammation of vocal cords ) inspiratory dyspnea obstruction locates within thorax expiratory dyspnea why?

  17. Phase of inspiration (Ptr <Patm) Phase of expiration (Ptr<Ppl) Phase of inspiration (Ptr>Ppl) Phase of expiration (Ptr > Patm) Patm Patm Ptr Ptr Ptr Ptr Ppl Ppl The effects on the phase of respiration on an extrathoracic variable obstruction The effects on the phase of respiration on an intrathoracic variable obstruction Ptr—intratrachel pressure Ppl—pleural pressure Patm—atmospheric pressure

  18. 2) peripheral airway obstruction(diameter<2mm): • peripheral airway character: • Wall: thin,without cartilage support; • Diameter changes with respiration; • keep tight connection to surrounding alveoli

  19. causes and mechanism: chronic obstructive pulmonary disease (chronic bronchitis,emphysema), severe pneumonia, atelectasis ,etc. → equal pressure point is moved up expiratory dyspnea

  20. point that Intra-airway pressure = extra-airway pressure Equal pressure point normal person makes forced expiration Emphysema patients makes forced expiration

  21. ii. Alteration of PaO2 ,PaCO2 in pulmonary ventilation disturbance PaO2↓ PaCO2↑ (type II RF)

  22. Ⅱ . Pulmonary gas exchange disturbance

  23. Pulmonary gas exchange disturbance diffusion impairmentVA / Q mismatch anatomic shunt

  24. i. Diffusion impairment Causes: area of R-M thickness of R-M diffusion time

  25. 1. Area of R-M Normal adult R-M: 80 m2 At rest, used R-M:35~40 m2 area of R-M : atelectasis,pulmonary consolidation,lobar resection, emphysema

  26. 2. Thickness of R-M : pulmonary edema, fibrosis, formation of pulmonary hyaline membrane, hydremia

  27. Alteration of PaO2 , PaCO2 PaO2↓ PaCO2 : N or ↓ according to compensatory ventilation why?

  28. Oxygenation of Blood

  29. PCO2( kPa ) PO2 13.33 PaO2 PvCO2 10.67 6.13 8.00 PvO2 5.33 PaCO2 2.67 0.75 s 0 0.50 0.25 Blood gas change when blood circulating through lungs Real line stands for normal person; broken line stands for patients with increased thickness of R-M

  30. ii. Ventilation-Perfusion Mismatch At rest: (VA): ~ 4L (Q) : ~ 5L VA/Q : 0.8 ratio

  31. Ventilation-Perfusion Coupling

  32. 1.Types and Causes 1) Hypoventilation of Partial alveoli (VA/Q↓) functional shunt or venous admixture Causes:Disorders of trachea or alveolus

  33. functional shunt : alveolar Ventilation (VA ), alveolar Perfusion (Q) have not VA /Q accordingly , even due to inflammation venous blood flowing through these units have not been totally arterialized and mixes into arterial blood, this process is called as functional shunt, also as venous admixture.

  34. O 2 CO 2 A血 V血

  35. V血 O 2↓ CO 2 V血

  36. 2) Low perfusion of Partial alveoli (VA/Q↑) dead space like ventilation: alveoli at diseased region have low perfusion,while ventilation is not decreased, alveolar ventilation can not be fully used. • causes:Disorders of pulmonary vessel(vessel inflammation, occlusion, spasm)

  37. O 2 CO 2 A血 V血

  38. O 2 CO 2 A血 V血

  39. 2. Alteration of PaO2 ,PaCO2 PaO2 ? N PaCO2

  40. 1) blood gas change in functional shunt Asthma C.bronchitis VA / Q functional shunt PaO2 ,PaCO2 compensatory respiration ventilation health region diseased region VA / Q VA / Q PaO2 ↑ , CaO2+, PaO2 ↓ , CaO2 ↓ PaCO2 ↓ CaCO2 ↓ PaCO2 ↑ ,CaCO2 ↑ PaO2 ↓, PaCO2 ? C . O2 and CO2 (ml/dl) PO2 and PCO2 Dissociation curve of O2 and CO2

  41. 2) blood gas change in dead space like ventilation p. embolism P. arteritis, DIC VA / Q dead space like ventilation other region Q functional shunt health region diseased region VA / Q VA / Q PaO2 ↓ , CaO2 ↓PaO2 ↑ , CaO2 + PaCO2 ↑ ,CaCO2 ↑ PaCO2 ↓ CaCO2 ↓ PaO2 ↓, PaCO2 ? C . O2 and CO2 (ml/dl) PO2 and PCO2 Dissociation curve of O2 and CO2

  42. iii. anatomic shunt(true shunt) 1、Under physiological condition anatomic shunt: bronchia vein venous bloodpulmonary vein A-V communicating branch true shunt: there are totally no gas exchange in the blood flowing through anatomic shunt, so anatomic shunt also called as true shunt. N: 2%-3%

  43. 2、Under pathological condition bronchiectasis flow of bronchial vein shock flow of A-V shunt true shunt atelectasis Consolidationlike true shunt of lung PaO2 PaCO2± or or

  44. summary restrictive Ventilation disturbance(PaO2↓ PaCO2↑) Hypoven- tilation  obstructive RF Gas exchange disturbance PaO2↓ PaCO2↑ ↓N) diffusion impairment V/Q mismatch true shunt↑(V/Q=0)

  45. Section 2 The functional and metabolic changes in RF

  46. Total change direction Comp. hypoxemia hypercapnia PaO2<60mmHg PaCO2>50mmHg Dysf. of external R. Effects on organ system Dist. of acid-base electrolyte Discom. PaO2<30mmHg PaCO2>80mmHg

  47. i. Respiratory Acidosis——type Ⅱ RF : CO2 retention Hyperkalemia: H+-K+ exchange Secretion from distal renal tubules ↓ hydrogen ion dissociatefrom H2CO3 carbonic acid ii. Metabolic Acidosis——Hypoxia → production of lactic acid↑ excretion↓ Ⅰ.Acid-base Disorders and Electrolytes Disorders

  48. Respiratory Alkalosis ---- type I RF Hypoxia compensation hyperventilation → PaCO2 ↓ Hypokalemia

More Related