Reported Acute Respiratory Distress Syndrome (ARDS) Mortality Rates

• Historical ARDS Mortality Rates (Studies Published in 2000): 30-40% (NEJM, 2000) [MEDLINE] [MEDLINE]
• ARDS Mortality Rate on Current Lung Protective Ventilation Strategies (Studies Published in 1999 and 2004): 13-23% (Intensive Care Med, 1999) [MEDLINE] (Intensive Care Med, 2004) [MEDLINE]
• ALIEN Study of ARDS Mortality Rates in the Current Era of Lung Protective Ventilation Strategies (Intensive Care Med, 2011) [MEDLINE]
  • ICU Mortality Rate: 42.7%
  • Hospital Mortality Rate: 47.8%
• ARDS Mortality Rate in Patients Without Clinical Improvement in pO2/FIO2 Ratio in First 24 hrs After Initiating Mechanical Ventilation: 53-68% (Intensive Care Med, 1999) [MEDLINE] (Intensive Care Med, 2004) [MEDLINE]
• Mortality Rate by Berlin Definition Class (JAMA, 2012) [MEDLINE]
  • Mild ARDS: 27% mortality rate (95% CI: 24%-30%)
  • Moderate ARDS: 32% mortality rate (95% CI: 29%-34%)
  • Severe ARDS: 45% mortality rate (95% CI: 42%-48%)

Predicted Duration of Mechanical Ventilation in Acute Respiratory Distress Syndrome (ARDS) Survivors by Berlin Definition Class (JAMA, 2012) [MEDLINE]

• Mild ARDS: 5 days (2-11 days)
• Moderate ARDS: 7 days (4-14 days)
• Severe ARDS: 9 days (5-17 days)

Predictors of Acute Respiratory Distress Syndrome (ARDS) Mortality

• Cirrhosis/End-Stage Liver Disease (see Cirrhosis)
• Failure of Pulmonary Function to Improve After 1 Week of Therapy
• Increased Physiologic Dead Space Fraction (VD/VT) in Early ARDS (Respir Care, 2014) [MEDLINE]
• Nonpulmonary Organ Dysfunction
• Sepsis (see Sepsis)
• Note: initial pO2/FIO2 ratio and initial indexes of ventilation do not predict mortality -> patients with the worse pO2/FIO2 ratios had the best survival

Postoperative Acute Respiratory Distress Syndrome (ARDS) Mortality

• Systematic Review/Meta-Analysis of Morbidity/Mortality in Post-Operative Acute Lung Injury (Lancet Respir Med, 2014) [MEDLINE]
  • Postoperative Acute Lung Injury is Associated with Increased In-Hospital Mortality Rate (Overall 19% Mortality Rate), Increased ICU Length of Stay, and Increased Hospital Length of Stay
  • Mortality Due to Acute Lung Injury Associated with Thoracic Surgery is Higher (26.5% mortality) than Acute Lung Injury Associated with Abdominal Surgery (12.2% Mortality) Rate
  • Lung Protective Mechanical Ventilation Strategies Decrease the Incidence of Postoperative Acute Lung Injury, But Do Not Impact the Mortality Rate

Post-Intensive Care Syndrome (PICS) (see Post-Intensive Care Syndrome)

General Comments

• Post-Intensive Care Syndrome (PICS) Constitutes New or Worsening Function in One or More of the Cognitive, Psychiatric, and Physical Domains After a Critical Illness

Clinical Studies

• Canadian Clinical Trials Group 5-Year Study of Acute Respiratory Distress Syndrome (ARDS) Sequelae (NEJM, 2011) [MEDLINE]: ARDS survivors (n = 109) studied at at 3, 6, and 12 months and at 2, 3, 4, and 5 years after discharge from the intensive care unit
  • Exercise Limitation (Decreased 6-Minute Walk Test) and Physical Dysfunction May Persist for Up to 5 yrs After ARDS
  • Pulmonary Function was Near Normal-Normal
  • Psychological Problems May Persist for Up to 5 years after ARDS
• Acute Respiratory Distress Syndrome (ARDS) Cognitive Outcomes Study (Am J Respir Crit Care Med, 2012) [MEDLINE]: study of ARDS survivors (n = 213)
  • Long-Term Cognitive Impairment was Present in 55% of Subjects
  • Anxiety was Present in 62% of Subjects
  • Depression was Present in 36% of Subjects
  • Post-Traumatic Stress Disorder (PTSD) was Present in 39% of Subjects
  • Impact of Hypoxemia
    • Presence of Hypoxemia is a Risk Factor for Long-Term Cognitive and Psychiatric Impairment
  • Impact of Fluid Management Strategy
    • Conservative Fluid Management Strategy is a Potential Risk Factor for Long-Term Cognitive Impairment
      • However, This Finding Requires Further Studies for Confirmation
• BRAIN-ICU Study of Patients with Respiratory Failure or Shock in the Medical/Surgical Intensive Care Unit (NEJM, 2013) [MEDLINE]: n = 821
  • Delirium Developed in 74% of Cases During Hospital Stay
  • Outcomes At 3 Months
    • 40% of Patients Had Impaired Global Cognition Scores that Were 1.5 Standard Deviations (SD) Below the Population Mean, Similar to Scores for Patients with Moderate Traumatic Brain Injury
    • 26% of Patients Had Scores 2 Standard Deviations (SD) Below the Population Mean (Similar to Scores for Patients with Mild Alzheimer’s Disease)
  • Outcomes At 12 Months
    • Similar Persistent Cognitive Dysfunction Occurs as in Those with Moderate Traumatic Brain Injury
    • Similar Persistent Cognitive Dysfunction Occurs as in Those with Mild Alzheimer’s Disease
  • Impact of Duration of Delirium
    • Longer Duration of Delirium was Significantly Associated with Worse Global Cognition at 3 and 12 Months and Worse Executive Function at 3 and 12 Months
  • Impact of Sedative Use
    • Use of Sedatives or Analgesics was Not Associated with Cognitive Impairment at 3 and 12 Months
  • Cognitive Dysfunction was Also Independent of Age, Pre-Existing Cognitive Impairment, Presence or Severity of Coexisting Conditions, and Organ Failure During Intensive Care Unit Stay
• Longitudinal Cohort Study of Depression, Posttraumatic Stress Disorder, and Functional Disability in Intensive Care Survivors from the BRAIN-ICU Study (Lancet Respir Med, 2014) [MEDLINE]: n = 821
  • At 3 Months
    • Approximately 37% of Patients Reported at Least Mild Depression (Depression was Mainly Due to Somatic Symptoms, Rather than Cognitive-Affective Symptoms)
      • Depressive Symptoms were Common Even in Patients without a History of Depression (Occurred in 30% of These Patients at 3 Months)
    • Approximately 7% of Patients Reported Posttraumatic Stress Disorder at 3 Months
    • Approximately 32% of Patients were Disabled in Their Activities of Daily Living (ADL’s)
    • Approximately 26% of Patients were Disabled in Their Instrumental Activities of Daily Living (IADL’s)
    • After Adjusting for Covariates, Younger Age was Associated with a Probability of Worse Posttraumatic Stress Disorder
  • At 12 Months
    • Approximately 33% of Patients Reported at Least Mild Depression (Depression was Mainly Due to Somatic Symptoms, Rather than Cognitive-Affective Symptoms)
      • Depressive Symptoms were Common Even in Patients without a History of Depression (Occurred in 29% of These Patients at 12 Months)
    • Approximately 7% of Patients Reported Posttraumatic Stress Disorder at 12 Months
    • Approximately 27% of Patients were Disabled in Their Activities of Daily Living (ADL’s)
    • Approximately 23% of Patients were Disabled in Their Instrumental Activities of Daily Living (IADL’s)
    • After Adjusting for Covariates, Younger Age was Associated with a Probability of Worse Posttraumatic Stress Disorder
• NHLBI ARDS Network Prospective Longitudinal (1 Year) Multicenter Study of Physical Impairment in Acute Respiratory Distress Syndrome (ARDS) Survivors (Am J Respir Crit Care Med, 2014) [MEDLINE]
  • ARDS Survivors Demonstrated Impairment in 6-Minute Walk Test Distance (Distance was 64% Predicted at 6 Months, 67% Predicted at 1 Year) and Short Form-36 (SF-36) Physical Function Outcome Measures
  • Impairment Appeared to Be Correlated with Mean Daily Corticosteroid Dose and ICU Length of Stay
• Prospective Longitudinal (2 Year) Multicenter Study of Physical Impairment in Acute Respiratory Distress Syndrome (ARDS) Survivors (Crit Care Med, 2014) [MEDLINE]
  • Muscle Weakness is Common at Hospital Discharge Following ARDS, Usually Recovering Within 1 Year
  • Muscle Weakness is Associated with Substantial Impairment in Physical Function and Health-Related QOL, Which Continue Beyond 12 Months
  • Corticosteroid Dose and Use of Neuromuscular Blockade Were Not Associated with the Development of Weakness

Decreased Quality of Life (QOL)

• Canadian Clinical Trials Group 5-Year Study of Acute Respiratory Distress Syndrome (ARDS) Sequelae (NEJM, 2011) [MEDLINE]: ARDS survivors (n = 109) studied at at 3, 6, and 12 months and at 2, 3, 4, and 5 years after discharge from the intensive care unit
  • Decreased QOL May Persist for Up to 5 yrs After ARDS
• Prospective Longitudinal (2 Year) Multicenter Study of Physical Impairment in Acute Respiratory Distress Syndrome (ARDS) Survivors (Crit Care Med, 2014) [MEDLINE]
  • Muscle Weakness is Common at Hospital Discharge Following ARDS, Usually Recovering Within 1 Year
  • Muscle Weakness is Associated with Substantial Impairment in Physical Function and Health-Related QOL, Which Continue Beyond 12 Months
  • Corticosteroid Dose and Use of Neuromuscular Blockade Were Not Associated with the Development of Weakness

Increased Costs and Use of Health Care Services

• Canadian Clinical Trials Group 5-Year Study of Acute Respiratory Distress Syndrome (ARDS) Sequelae (NEJM, 2011) [MEDLINE]: ARDS survivors (n = 109) studied at at 3, 6, and 12 months and at 2, 3, 4, and 5 years after discharge from the intensive care unit
  • Increased Health Care Costs and Increased Use of Health Care Services May Persist for Up to 5 yrs After ARDS
  • Patients with More Coexisting Illnesses Incurred Greater 5-Year Costs
• French Cluster Analysis Study of Patient Disposition and Outcome After Critical Illness (Chest, 2022) [MEDLINE]: n = 77,132 ICU ICU survivors who spent ≥2 nights in a French ICU during 2018 and were treated with invasive mechanical ventilation or vasopressors or inotropes (trauma, burn, organ transplant, stroke, and neurosurgical patients were excluded)
  • 89% of All Patients were Able to Return to Home
    • In the Year After Discharge, These Patients Spent a Median of 330 (Interquartile Range [IQR]: 283-349) Days at Home
  • At 1 Year
    • 77% of Patients were Still at Home
    • 17% Had Died
    • 51% Had Been Re-Hospitalized
    • 10% Required Further ICU Admission
  • 48% of Patients Required Rehabilitation Facilities and 5.7% Required Hospital at Home
  • Three Clusters of Patients with Distinct Post-ICU Trajectories were Identified
    • Patients in Cluster 1 (68% of Total) Survived and Spent Most of the Year at Home (338 [323-354] Days)
    • Patients in Cluster 2 (18%) Had More Complex Trajectories, But Most Could Return Home (91%), Spending 242 (174-277) Days at Home
    • Patients in Cluster 3 (14%) Died with Only 37% Returning Home for 45 (15-90) Days