Acute respiratory distress syndrome carre

1,721 views

Published on

Published in: Health & Medicine
0 Comments
3 Likes
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total views
1,721
On SlideShare
0
From Embeds
0
Number of Embeds
10
Actions
Shares
0
Downloads
71
Comments
0
Likes
3
Embeds 0
No embeds

No notes for slide

Acute respiratory distress syndrome carre

  1. 1. ACUTE RESPIRATORY DISTRESS SYNDROME Lyonel Carre PGY2 SICU conf 10/02/06
  2. 2. ARDS Definition <ul><li>Severe, acute lung injury involving diffuse alveolar damage, increased microvascular permeability and non cardiogenic pulmonary edema </li></ul><ul><li>Acute refractory hypoxemia </li></ul><ul><li>Annual incidence 75/100,000 in the US </li></ul><ul><li>High mortality- 40%-60% </li></ul><ul><li>First described in 1967 </li></ul>
  3. 3. ARDS Criteria <ul><li>Acute onset of respiratory failure </li></ul><ul><li>Bilateral infiltrate on CXR(some cases do present unilaterally or with pleural effusion </li></ul><ul><li>PCWP <18 or absence of left atrial htn, </li></ul><ul><li>PaO2/FiO2 < 200 </li></ul>
  4. 4. ARDS <ul><li> </li></ul>
  5. 5. ARDS mechanism of lung injury <ul><li>Activation of inflammatory mediators and cellular components resulting in damage to capillary endothelial and alveolar epithelial cells </li></ul><ul><li>Increased permeability of alveolar capillary membrane </li></ul><ul><li>Influx of protein rich edema fluid and inflammatory cells into air spaces </li></ul><ul><li>Dysfunction of surfactant </li></ul>
  6. 7. ARDS causes <ul><li>Direct Lung Injury : </li></ul><ul><li>a) PNA and aspiration of gastric contents </li></ul><ul><li>or other causes of chemical pneumonitis </li></ul><ul><li>b) pulmonary contusion, penetrating lung injury </li></ul><ul><li>c) fat emboli </li></ul><ul><li>d) near drowning </li></ul><ul><li>e) inhalation injury </li></ul><ul><li>f) reperfusion pulm edema after lung transplant </li></ul>
  7. 8. ARDS causes <ul><li>Indirect lung injury </li></ul><ul><li>a) sepsis </li></ul><ul><li>b) severe trauma w/ shock hypoperfusion </li></ul><ul><li>c) drug over dose </li></ul><ul><li>d) cardiopulmonary bypass </li></ul><ul><li>e) acute pancreatitis </li></ul><ul><li>f) transfusion of multp blood products </li></ul>
  8. 9. Stages of ARDS <ul><li>1. Exudative (acute) phase - 0- 4 days </li></ul><ul><li>2. Proliferative phase - 4- 8 days </li></ul><ul><li>3. Fibrotic phase - >8 days </li></ul><ul><li>4. Recovery </li></ul>
  9. 10. ARDS exudative and fibrotic phases
  10. 11. Predictors of outcome <ul><li>Factors whose presence can be used to predict the risk of death at the time of diagnosis of acute lung injury and the acute respiratory distress syndrome include </li></ul><ul><li>a)chronic liver disease </li></ul><ul><li>b)non-pulmonary organ dysfunction, </li></ul><ul><li>c)sepsis, </li></ul><ul><li>d)advanced age. </li></ul>
  11. 12. ARDS network study <ul><li>patients with ALI/ARDS at 10 centers, 861 patients </li></ul><ul><li>Patients randomized to tidal volumes of 12 mL /kg or 6 ml/kg(volume control, assist control, plat Press = 30 cm H2O) </li></ul><ul><li>22% reduction in mortality in patients receiving smaller tidal volume </li></ul><ul><li>Number-needed to treat: 12 patients </li></ul>
  12. 13. ARDS Network Study   6ml/kg 12m/kg PaCO 2 43 ± 12 36 ±9 Respiratory rate 30 ± 7 17 ± 7 PaO 2 /F /FIO 2 160 ± 68 177 ± 81 Plateau pressure 26 ± 7 34 ± 9 PEEP 9.2 ± 3.6 8.6 ± 4.2
  13. 14. ARDSnet protocol <ul><li>Calculated predicted body weight(pbw) </li></ul><ul><li>male: 50+2.3[height(inches)-60] </li></ul><ul><li>female: 45.5+2.3[height(inches)-60] </li></ul><ul><li>Mode: Volume assist-control </li></ul><ul><li>Change rate to adjust minute ventilation(not>35/min) </li></ul><ul><li>PH goal 7.30-7.45 </li></ul><ul><li>Plateau press<30cmh20 </li></ul><ul><li>PaO 2 goal: 55-80mmhg or SpO 2 88-95% </li></ul><ul><li>FiO 2 /PEEP combination to achieve oxygenation goal. </li></ul>
  14. 15. ARDSnet How to select PEEP <ul><li>PEEP/FiO 2 relationship to maintain adequate PaO 2 /SpO 2 </li></ul><ul><li>PaO 2 goal: 55-80mmHg or SpO2 88-95% use FiO2/PEEP combination to achieve oxygenation goal </li></ul>FIO 2 PEEP 20-24 18 16 14 14 14 12 10 10 10 8 8 5 5 1.0 0.9 0.9 0.9 0.8 0.7 0.7 0.7 0.6 0.5 0.5 0.4 0.4 0.3
  15. 16. ARDSNet Ventilator protocol
  16. 17. ARDS Ventilator setting <ul><li>Greatest Lung strain PC IRV(I:E 2:1), least w/ PC (I:E 1:2) and intermediate w/ VC (I:E 1:2) </li></ul><ul><li>No difference in gas exchanged, hemodynamics, and plateau pressure </li></ul><ul><li>No difference in outcome w/ ARDS pts randomized to pressure control vs volume cycled PC(n=37), VC(n=42). </li></ul><ul><li>Edibam et al Am J Resp Crit Care Med 2003 </li></ul><ul><li>Esteban et al , Chest 2000 </li></ul>
  17. 18. Permissive Hypercapnia <ul><li>Low Vt (6ml/kg) to prevent over-distention </li></ul><ul><li>increase respiratory rate to avoid very high level of hypercapnia </li></ul><ul><li>PaCO 2 allowed to rise </li></ul><ul><li>Usually well tolerated </li></ul><ul><li>May be beneficial </li></ul><ul><li>Potential Problems: tissue acidosis, autonomic dysregulation, CNS effect, and circulatory effects </li></ul>
  18. 19. HISTORY OF ALTERNATIVE VENTILATORY STRATEGIES FOR ACUTE LUNG INJURY AND THE ACUTE RESPIRATORY DISTRESS SYNDROME.
  19. 20. ARDS Treatment <ul><li>Ventilator-induced lung injury: it was previously thought that oxygen toxicity was one of the most important factors in the progression of ARDS and resultant mortality. Recently, it was found that high volume(volutrauma) and high press(barotrauma) are equally if not more detrimental to these pts </li></ul><ul><li>Treatment strategy is one of low volume and high frequency ventilation(ARDSNet protocol) </li></ul><ul><li>Search for and treat the underlying cause </li></ul><ul><li>Treat abdominal infx promptly w/ abx and surgery </li></ul><ul><li>Ensure adequate nutrition and place on GI/DVT prophylaxis </li></ul><ul><li>Prevent and treat nosocomial infx </li></ul><ul><li>Consider short course of high dose steroids in pts w/ severe dz that is not resolving . </li></ul>
  20. 21. When all else fails.. <ul><li>Recruitment maneuvers </li></ul><ul><li>Prone </li></ul><ul><li>Inhaled nitric oxide </li></ul><ul><li>High frequency oscillation </li></ul>
  21. 22. ARDSnet and Long-term outcome <ul><li>120pts randomized to low Vt or high Vt </li></ul><ul><li>a) 25%mortality w/ low tidal volume </li></ul><ul><li>b) 45% mortality w/ high tidal volume </li></ul><ul><li>20% had restricitve defect and 20% had obstructive defect 1 yr after recovery </li></ul><ul><li>About 80% had DLCO reduction 1 yr after recovery </li></ul><ul><li>Standardized tested showed health-related quality of life lower than normal </li></ul><ul><li>No difference in long-term outcomes between tidal volume group </li></ul><ul><li>Orme Am J respir Crit Care Med 2003 </li></ul>

×