Contents

Search

acute respiratory distress syndrome; acute lung injury (ARDS, ALI)

ARDS is the most severe form of acute respiratory failure due to acute pulmonary injury. It is a diagnosis of exclusion. Classification: 1) degree of hypoxemia: [11] - mild (200 mm Hg < PaO2/FIO2 <= 300 mm Hg)* - moderate (100 mm Hg < PaO2/FIO2 <= 200 mm Hg)* - severe (PaO2/FIO2 <= 100 mm Hg)* 2) 4 ancillary variables for severe ARDS: [11] - radiographic severity - respiratory system compliance (<=40 mL/cm H2O) - positive end-expiratory pressure >= 10 cm H2O) - corrected expired volume per minute (>= 10 L/min) * with PEEP > 5 cm H2O Etiology: 1) direct pulmonary injury a) pneumonia or other pulmonary infection [2] (most important) b) aspiration of gastric contents c) major trauma: pulmonary contusion d) near drowning e) inhalation injury - mechanical ventilation - lower tidal volumes may reduce risk 2) indirect pulmonary injury a) sepsis, particularly from an abdominal source b) hemorrhagic shock c) drug overdose (heroin, methadone, barbiturates) d) major trauma - multiple fractures e) multiple blood transfusions f) pancreatitis Epidemiology: - incidence & mortality increases with age [6] Pathology: 1) disruption of the alveolar capillary membrane 2) increased vascular permeability 3) accumulation of neutrophils & protein rich edema in the alveolar space 4) up to 70% of alveoli may be non-functional 5) may be component of alveolar dead space [6] 6) a fibroproliferative stage may occur within 2 weeks of onset a) loss of alveolar structures b) obliteration of vasculature c) interstitial infliltration of chronic inflammatory cells d) deposition of type 1 collagen e) severity of fibroproliferative reaction correlates with increased mortality 7) varying degrees of multiorgan failure accompany ARDS Clinical manifestations: 1) rapid onset a) < 48 hours after precipitating event [2]; < 1 week [2] b) generally < 24 hours 2) severe dyspnea 3) tachycardia 4) tachypnea 5) diffuse bilateral crackles on chest auscultation 6) hypoxemic respiratory failure Diagnostic criteria: - onset within 1 week of ARDS insult (most within 72 hours) - bilateral lung opacities consistent with pulmonary edema - acute respiratory failure unrelated to heart failure or volume overload - PaO2/FiO2 of < 300 mm Hg on at least 5 mm PEEP - PaO2/FiO2 of 100-200 (moderate); < 100 mm Hg (severe) Laboratory: 1) arterial blood gas (ABG) a) hypoxemia, pO2/fiO2 < 200 mm Hg for ARDS b) pO2/fiO2 < 300 mm Hg for acute lung injury 2) pulse oximetry: SaO2 < 88% 3) sputum for gram stain & culture (essential) Special laboratory: 1) hemodynamic monitoring a) distinguish cardiogenic pulmonary edema from ARDS b) pulmonary artery occlusion pressure < 18 mm Hg c) not routinely recommended 2) echocardiography - distinguish cardiogenic pulmonary edema from ARDS 3) fiberoptic bronchoscopy with bronchoalveolar lavage &/or bronchoscopic biopsy is generally performed as indicated after CT [31] Radiology: - chest radiograph a) diffuse bilateral pulmonary infiltrates b) no pulmonary vascular redistribution (i.e. no heart failure) c) no cardiomegaly d) pleural effusions are rare in the absence of another condition predisposing to pleural effusion - chest CT as indicated [31] Differential diagnosis: 1) cardiogenic pulmonary edema - enlarged cardiac silhouette on chest X-ray - improvement with diuresis &/or afterload reduction 2) diffuse alveolar hemorrhage - evidence of vasculitis, acute kidney injury, hematuria - hemosiderin-laden macrophages with bronchoalveolar lavage - associated with stem cell transplantation 3) acute eosinophilic pneumonia - cough, fever, pleuritic chest pain, myalgia, precipitated by smoking - > 15% eosinophils in bronchoalveolar lavage fluid 4) hypersensitivity pneumonitis - onset generally over weeks, course progressive - exposure history (farmers, birds, hot tubs) 5) acute interstitial pneumonia - may be impossible to distinguish for ARDS - no inciting factors for ARDS - may responed to glucocorticoids 6) pulmonary embolism unlikely if multifocal pulmonary opacities on chest X-ray [42] Complications: 1) overall mortality 30-40% worldwide (50 countries) [22] - mortality is 50% when associated with sepsis 2) multiple organ dysfunction & secondary pulmonary infections may occur if the patient survives the acute phase 3) delirium in the elderly Management: 1) use high-flow nasal oxygen vs conventional oxygen therapy to reduce risk of intubation [40] - noninvasive positive-pressure ventilation (NPPV) delivered via helmet may be alternative to mechanical ventilation [23] 2) mechanical ventilation a) oxygenation - target partial pressure of oxygen 55-80 mm Hg NEJM [44] - oxygen saturation levels titrated > 96% SaO2 - no benefit in titration to > 97% SaO2 - oxygen saturation titrated to 88-92% results in higher 90 day mortality (44% vs 30%) [39] b) PEEP of 5-12 cm H2O 1] 8 vs 13 cm H20 associated with similar outcomes [3] 2] higher PEEP may reduce morbidity but not mortality [3] - higher PEEP recommended for patients with moderate-to-severe ARDS [43] 3] use lowest PEEP necessary to achieve SaO2 of 88% with FiO2 of < 60% without hypotension [2,13] 4] individualizing PEEP with esophageal balloon-guided PEEP titration does not improve outcomes [35] c) lung protective ventilation (permissive hypercapnia) d) peak inspiratory pressure < 30-35 mm Hg e) end-expiratory pressure (plateau pressure) < 30 cm Hg [14] f) tidal volume 6 mL/kg IBW [2,15,28] (4-8 mL/kg [40]) - decrease tidal volume by 1 mL/kg as needed to keep plateau pressure < 30 cm Hg - low tidal volume ventilation is the only intervention shown to reduce mortality in patients with ARDS of any severity [24] - low tidal-volume ventilation, prone positioning, & early neuromuscular blockade reduce mortality [30,43] g) recruitment maneuvers (PEEP of 40 cm of water for 40 seconds) of no benefit [30], PEEP of 45 cm of water for 2 minutes harmful [32] 2) prone positioning during mechanical ventilation (4-20 hours/day) - mortality benefit in patients with moderate-severe ARDS [2,25] - >= 16 hours/day in prone position [2,16] - may improve oxgenation decrease 28-day & 90-day mortality [16] - begin prone positioning early in patients on low tidal-volume ventilation [2] - prone positioning does not reduce the time to ECMO weaning in patients with severe ARDS [41] 3) recruitment maneuvers (short duration higher inspiratory pressure to open atelectatic alveoli) strongly discouraged. [43] 4) neuromuscular blockade may have a survival benefit in patients with moderate-severe ARDS [26] - early treatment of patients with severe ARDS [43] - partial pressure of oxygen [PaO2]:fraction of inspired oxygen [FiO2] <100) -l imit courses to 48 hours or shorter [43] - cisatricurium besylate for 48 hours [26] - mortality reduction at 28 days 24% vs 33% [26] - more important than intravascular volume manangement [30] - do not routinely use continuous infusion of neuromuscular blocking agent [40] - no benefit to early neuromuscular blockade [37] 5) intravascular volume management - maintain lowest possible intravascular volume compatible with adequate tissue perfusion - limit IV fluid boluses - use diuretics to keep central venous pressure low [2] - implement after off vasopressors for 12 hours - target central venous pressure = 4 mm Hg [2,7] - conservative fluid management may have short-term benefit [7] - no mortality benefit [30] 6) glucocorticoids - may be of benefit for adrenal insufficiency - hydrocortisone 50 mg IV every 6 hours + fludrocortisone 50 ug PO QD [5] - glucocorticoids (no adrenal insufficiency) - may be of benefit in fibroproliferative phase - methyprednisolone 1 mg/kg IV started early & tapered over 28 days of benefit [9] - may be of benefit for Covid-19 & community-acquired pneumonia - early high dose glucocorticoids of no benefit [18] - number needed to harm = 3 (infection) [18] - of no benefit for acute treatment of ARDS [2] 7) pulmonary artery catheter of no benefit [8] 8) venovenous extracorporeal membrane oxygenation (ECMO) of no benefit [34] - recommended for patients with severe ARDS (PaO2:FiO2 <80 or pH <7.25 with PaCO2 >=60 mm Hg), low certainty of evidence [43] 9) unproven therapies [2] a) inotropic agents (unproven, controversial) b) nitric oxide: 1] reduces pulmonary artery pressure & improves oxygenation 2] no improvement in mortality [2] 3] not recommended [2] c) ketoconazole not recommended [2] d) surfactant not recommended [2] e) statin of no benefit [17] f) airway pressure release ventilation g) IFN-beta-1a of no benefit [38] 10) any red cell transfusion may increase mortality [10] Prognosis: 1) sepsis is most lethal form [6] 2) most survivors discharged to long-term care facility [6] 3) most survivors regain baseline lung function within 12 months Notes: - non-standard care frequent in Europe [22]

Related

neonatal respiratory distress syndrome (hyaline membrane disease, neonatal RDS)

Specific

electronic cigarette vaping-associated lung injury (VALI, EVALI) transfusion-related acute lung injury (TRALI)

General

respiratory distress syndrome (RDS) acute respiratory failure

References

  1. Manual of Medical Therapeutics, 28th ed, Ewald & McKenzie (eds), Little, Brown & Co, Boston, 1995, pg 249-50
  2. Medical Knowledge Self Assessment Program (MKSAP) 11, 14, 15, 16, 17, 18. American College of Physicians, Philadelphia 1998, 2006, 2009, 2012, 2015, 2018. - Medical Knowledge Self Assessment Program (MKSAP) 19 Board Basics. An Enhancement to MKSAP19. American College of Physicians, Philadelphia 2022
  3. Brower RG, Lanken PN, MacIntyre N, Matthay MA, Morris A, Ancukiewicz M, Schoenfeld D, Thompson BT; National Heart, Lung, and Blood Institute ARDS Clinical Trials Network. Higher versus lower positive end-expiratory pressures in patients with the acute respiratory distress syndrome. N Engl J Med. 2004 Jul 22;351(4):327-36. PMID: 15269312 - Levy MM. PEEP in ARDS--how much is enough? N Engl J Med. 2004 Jul 22;351(4):389-91. No abstract available. PMID: 15269320 - Mercat A et al, Positive end-expiratory pressure setting in adults with acute lung injury and acute repsiratory distress syndrome: A randomized controlled trial. JAMA 2008, 299:646 PMID: 18270353 - Gattinoni L and Caironi P Refining ventilatory treatment for acute lung injury and acute respiratory distress syndrome. JAMA 2008, 299:691 PMID: 18270359
  4. Rubenfeld GD, Caldwell E, Peabody E, Weaver J, Martin DP, Neff M, Stern EJ, Hudson LD. Incidence and outcomes of acute lung injury. N Engl J Med. 2005 Oct 20;353(16):1685-93. PMID: 16236739
  5. Annane D et al, Effect of low doses of corticosteroids in septic shock patients with or without early acute respiratory distress syndrome Crit Care Med 2006; 34:22 PMID: 16374152
  6. Mather Matthay, Grand Rounds, UC Davis, Feb 16, 2006
  7. Comparison of Two Fluid-Management Strategies in Acute Lung Injury. N Engl J Med. 2006 May 21; [Epub ahead of print] PMID: 16714767 - Rivers EP. Fluid-Management Strategies in Acute Lung Injury -- Liberal, Conservative, or Both? N Engl J Med. 2006 May 21; [Epub ahead of print] PMID: 16714769
  8. The National Heart, Lung, and Blood Institute Acute Respiratory Distress Syndrome (ARDS) Clinical Trials Network. Pulmonary- artery versus central venous catheter to guide treatment of acute lung injury. N Engl J Med 2006; 354:2213 PMID: 16714768 - Shore D Pulmonary-artery catheters - Peace at last? N Engl J Med 2006; 354:2773 PMID: 16714770
  9. Meduri GU, Golden E, Freire AX, Taylor E, Zaman M, Carson SJ, Gibson M, Umberger R. Methylprednisolone infusion in early severe ARDS: results of a randomized controlled trial. Chest. 2007 Apr;131(4):954-63. PMID: 17426195 - Annane D. Glucocorticoids for ARDS: Just Do It! Chest. 2007 Apr;131(4):945-6. No abstract available. PMID: 17426190
  10. Netzer G et al, Association of RBC transfusion with mortality in patients with acute lung injury, Chest 2007, 132:1116 PMID: 17505028
  11. The ARDS Definition Task Force Acute Respiratory Distress Syndrome: The Berlin Definition JAMA. 2012;():1-8 PMID: 22797452 http://jama.jamanetwork.com/article.aspx?articleID=1160659
  12. Neto AS et al. Association between use of lung-protective ventilation with lower tidal volumes and clinical outcomes among patients without acute respiratory distress syndrome: A meta-analysis. JAMA 2012 Oct 24/31; 308:1651 PMID: 23093163
  13. Putensen C, Theuerkauf N, Zinserling J, Wrigge H, Pelosi P. Meta-analysis: ventilation strategies and outcomes of the acute respiratory distress syndrome and acute lung injury. Ann Intern Med. 2009 Oct 20;151(8):566-76. PMID: 19841457
  14. The NNT: Lung protective Ventilation Strategy for Intubated Patients with ARDS (Acute Respiratory Distress Syndrome). http://www.thennt.com/nnt/lung-protective-ventilation-for-ards/ - Petrucci N, Iacovelli W. Lung protective ventilation strategy for the acute respiratory distress syndrome. Cochrane Database Syst Rev. 2007 Jul 18;(3):CD003844. PMID: 17636739
  15. Patroniti N, Isgro S, Zanella A. Clinical management of severely hypoxemic patients. Curr Opin Crit Care. 2011 Feb;17(1):50-6 PMID: 21157316
  16. Guerin C et al Prone Positioning in Severe Acute Respiratory Distress. N Engl J Med 2013 Jun 6; 368:2159 PMID: 23688302 Free Article http://www.nejm.org/doi/full/10.1056/NEJMoa1214103 - Soo Hoo GW In Prone Ventilation, One Good Turn Deserves Another. N Engl J Med. May 20, 2013 PMID: 23688300 http://www.nejm.org/doi/full/10.1056/NEJMe1304349
  17. McAuley DF et al. Simvastatin in the acute respiratory distress syndrome. N Engl J Med 2014 Sep 30 PMID: 25268516
  18. The NNT: Corticosteroids for Acute Respiratory Distress Syndrome (ARDS) http://www.thennt.com/nnt/steroids-for-acute-respiratory-distress-syndrome-ards/ - Adhikari N, Burns KE, Meade MO Pharmacologic therapies for adults with acute lung injury and acute respiratory distress syndrome. Cochrane Database Syst Rev. 2004 Oct 18;(4):CD004477. PMID: 15495113
  19. Santa Cruz R, Rojas JI, Nervi R, Heredia R, Ciapponi A. High versus low positive end-expiratory pressure (PEEP) levels for mechanically ventilated adult patients with acute lung injury and acute respiratory distress syndrome. Cochrane Database Syst Rev. 2013 Jun 6;6:CD009098 PMID: 23740697
  20. Hudson LD, Milberg JA, Anardi D, Maunder RJ. Clinical risks for development of the acute respiratory distress syndrome. Am J Respir Crit Care Med. 1995 Feb;151(2 Pt 1):293-301. PMID: 7842182
  21. Acute Respiratory Distress Syndrome Network. Ventilation with lower tidal volumes as compared with traditional tidal volumes for acute lung injury and the acute respiratory distress syndrome. The Acute Respiratory Distress Syndrome Network. N Engl J Med. 2000 May 4;342(18):1301-8. PMID: 10793162 Free full text
  22. Bellani G et al. Epidemiology, patterns of care, and mortality for patients with acute respiratory distress syndrome in intensive care units in 50 countries. JAMA 2016 Feb 23; 315:788 PMID: 26903337
  23. Patel BK, Wolfe KS, Pohlman AS, Hall JB, Kress JP. Effect of noninvasive ventilation delivered by helmet vs face mask on the rate of endotracheal intubation in patients with acute respiratory distress syndrome: A randomized clinical trial. JAMA 2016 May 15; PMID: 2717984 - Beitler JR, Owens RL, Malhotra A. Unmasking a role for noninvasive ventilation in early acute respiratory distress syndrome. JAMA 2016 May 15; PMID: 27179463
  24. NEJM Konwledge+ Question of the Week For August 30, 2016 http://knowledgeplus.nejm.org/question-of-week/347/
  25. Guerin C, Reignier J, Richard JC et al Prone Positioning in Severe Acute Respiratory Distress Syndrome. N Engl J Med 2013; 368:2159-2168. June 6, 2013 PMID: 23688302 Free Article
  26. Papazian L, Forel JM, Gacouin A et al. Neuromuscular blockers in early acute respiratory distress syndrome. N Engl J Med 2010 Sep 16; 363:1107. PMID: 20843245 Free Article
  27. Dushianthan A, Grocott MP, Postle AD, Cusack R. Acute respiratory distress syndrome and acute lung injury. Postgrad Med J 2011 Jun 7; 87:612. Review PMID: 21642654
  28. Malhotra A. Low-tidal-volume ventilation in the acute respiratory distress syndrome. N Engl J Med 2007 Sep 15; 357:1113 PMID: 17855672 Free PMC Article
  29. Ware LB, Matthay MA. The acute respiratory distress syndrome. N Engl J Med 2000 May 4; 342:1334 PMID: 10793167
  30. NEJM Knowledge + Question of the Week. October 3, 2017 https://knowledgeplus.nejm.org/question-of-week/349/
  31. Thompson BT, Chambers RC, Liu KD. Acute respiratory distress syndrome. N Engl J Med 2017 Aug 10; 377:562. PMID: 28792873 http://www.nejm.org/doi/full/10.1056/NEJMra1608077
  32. Writing Group for the Alveolar Recruitment for Acute Respiratory Distress Syndrome Trial (ART) Investigators. Cavalcanti AB, Suzumura EA, Laranjeira LN et al Effect of Lung Recruitment and Titrated Positive End-Expiratory Pressure (PEEP) vs Low PEEP on Mortality in Patients With Acute Respiratory Distress SyndromeA Randomized Clinical Trial. JAMA. Published online September 27, 2017. PMID: 28973363 http://jamanetwork.com/journals/jama/fullarticle/2654894 - Sahetya SK, Brower RG. Lung recruitment and titrated PEEP in moderate to severe ARDS: Is the door closing on the open lung? JAMA 2017 Sep 27 PMID: 28973075
  33. Howell MD, Davis AM Management of ARDS in Adults. JAMA. 2018;319(7):711-712. Feb 20. PMID: 29466577 https://jamanetwork.com/journals/jama/fullarticle/2673134
  34. Combes A, Hajage D, Capellier G et al Extracorporeal Membrane Oxygenation for Severe Acute Respiratory Distress Syndrome. N Engl J Med 2018; 378:1965-1975. May 24, 2018 PMID: 29791822 https://www.nejm.org/doi/full/10.1056/NEJMoa1800385
  35. Beitler JR, Sarge T, Banner-Goodspeed VM et al. Effect of titrating positive end-expiratory pressure (PEEP) with an esophageal pressure-guided strategy vs an empirical high PEEP-FIO2 strategy on death and days free from mechanical ventilation among patients with acute respiratory distress syndrome: A randomized clinical trial. JAMA 2019 Feb 18; PMID: 30776290 https://jamanetwork.com/journals/jama/fullarticle/2725206 - Cavalcanti AB, Amato MBP, Serpa-Neto A. The elusive search for "best PEEP" and whether esophageal pressure monitoring helps. JAMA 2019 Feb 18 PMID: 30776293 https://jamanetwork.com/journals/jama/fullarticle/2725205
  36. Fan E, Del Sorbo L, Goligher EC An Official American Thoracic Society/European Society of Intensive Care Medicine/Society of Critical Care Medicine Clinical Practice Guideline: Mechanical Ventilation in Adult Patients with Acute Respiratory Distress Syndrome. Am J Respir Crit Care Med. 2017 May 1;195(9):1253-1263. PMID: 28459336
  37. The National Heart, Lung, and Blood Institute PETAL Clinical Trials Network. Early neuromuscular blockade in the acute respiratory distress syndrome. N Engl J Med. 2019 May 23;380(21):1997-2008 PMID: 31112383 https://www.nejm.org/doi/10.1056/NEJMoa1901686 - Slutsky AS, Villar J. Early paralytic agents for ARDS? Yes, no, and sometimes. N Engl J Med. 2019 May 23;380(21):2061-2063. PMID: 31112382 https://www.nejm.org/doi/10.1056/NEJMe1905627
  38. Ranieri VM, Pettila V, Karvonen MK et al Effect of Intravenous Interferon beta-1a on Death and Days Free From Mechanical Ventilation Among Patients With Moderate to Severe Acute Respiratory Distress Syndrome. A Randomized Clinical Trial. JAMA. Published online February 17, 2020 PMID: 32065831 https://jamanetwork.com/journals/jama/fullarticle/2761314 - Shankar-Hari M, Calfee CS. Lack of Clinical Benefit of Interferon beta-1a Among Patients With Severe Acute Respiratory Distress Syndrome. Time to Overhaul Drug Trials in ARDS? JAMA. Published online February 17, 2020 PMID: 32065830 https://jamanetwork.com/journals/jama/fullarticle/2761313
  39. Barrot L, Asfar P, Mauny F et al. Liberal or conservative oxygen therapy for acute respiratory distress syndrome. N Engl J Med 2020 Mar 12; 382:999 PMID: 32160661
  40. Angus DC, Seymour CW, Bibbins-Domingo K. Caring for Patients With Acute Respiratory Distress Syndrome. Summary of the 2023 ESICM Practice Guidelines. JAMA. Published online June 17, 2023 PMID: 37329332 https://jamanetwork.com/journals/jama/fullarticle/2806597
  41. Schmidt M, Hajage D, Lebreton G et al Prone Positioning During Extracorporeal Membrane Oxygenation in Patients With Severe ARDS. The PRONECMO Randomized Clinical Trial. JAMA. Published online December 1, 2023 PMID: 38038395 https://jamanetwork.com/journals/jama/fullarticle/2812529
  42. NEJM Knowledge+ Question of the Week. Jan 16, 2024 https://knowledgeplus.nejm.org/question-of-week/1875/ - Gorman EA, O'Kane CM, McAuley DF. Acute respiratory distress syndrome in adults: diagnosis, outcomes, long-term sequelae, and management. Lancet. 2022 Oct 1;400(10358):1157-1170. PMID: 36070788 Review.
  43. Qadir N et al. An update on management of adult patients with acute respiratory distress syndrome: An official American Thoracic Society clinical practice guideline. Am J Respir Crit Care Med 2024 Jan 1; 209:24. PMID: 38032683 https://www.atsjournals.org/doi/10.1164/rccm.202311-2011ST
  44. NEJM Knowledge+