Acute Respiratory Distress Syndrome

TIMING OF LOW TIDAL VOLUME VENTILATION AND INTENSIVE CARE UNIT MORTALITY IN ACUTE RESPIRATORY DISTRESS SYNDROME (Needham DM et al.  Am J Respir Crit Care Med. 2015: 191(2) 177-185)

Link to original journal article

This was an observational cohort study of 482 patients with ARDS.  Low tidal volume ventilation was said to be £ 6.5ml/kg predicted body weight.  Within 12 hours of meeting ARDS criteria, 68% of patients received tidal volumes >6.5ml/kg, and within this group of patients only 56% of them ever received low tidal volume ventilation.  While adjusting for pH, respiratory rate and severity of hypoxemia, initial tidal volume was significantly associated with mortality. An increase of 1ml/kg initial tidal volume was associated with a 23% increase in mortality (p=0.008) and an increase of 1ml/kg after 12 hours of ARDS was associated with a 15% increase in mortality.

Final statement:  Initial tidal volumes >6.5ml/kg were associated with increased mortality in ARDS.

OXYGENATION RESPONSE TO POSITIVE END-EXPIRATORY PRESSURE PREDICTS MORTALITY IN ACUTE RESPIRATORY DISTRESS SYNDROME.  A SECONDARY ANALYSIS OF THE LOVS AND EXPRESS TRIALS (Gligher et al. Am J Respir Crit Car Med. 2014 Jul 1: 190(1):70-6)

Link to original journal article

This was a further analysis of the Lung open ventilation study (LOVS) and the ExPress study to look at the association of increased PEEP and mortality.  In the LOVS study, of those whose PEEP was increased, 48% had at least a 25mmHg increase in PaO2:FiO2 which was associated with a lower mortality, when compared to those who didn’t have an increase in PaO2:FiO2.  In the combined studies, oxygenation response to a change in PEEP was only significantly associated with mortality in patients with more severe ARDS.

Final statement: Improvement in oxygenation with increased PEEP was associated with lower mortality in ARDS.

DRIVING PRESSURE AND SURVIVIAL IN ACUTE RESPIRATORY DISTRESS SYNDROME (Amato et al. N Engl J Med. 2015 Feb 19: 372(8):747-55)

Link to original journal article

Driving pressure is defined as tidal volume divided by respiratory system compliance.  This was a secondary analysis of 3562 ARDS patients from nine randomised trials.  In this study the authors found that driving pressure was strongly associated with survival, a 7cm of H2O increase in driving pressure was associated with a 41% increased risk of mortality.  This risk was somewhat reduced, although still present, with low tidal volume ventilation.  Changes in tidal volume and PEEP were only associated with survival if mediating a change in driving pressure.

Final statement:  Driving pressure is strongly associated with survival/mortality.

ROUSUVASTATIN FOR SEPSIS-ASSOCIATED ACUTE RESPIRATORY DISTRESS SYNDROME (Truwit et al. N Engl J Med. 2014 Jun 5: 370 (23):2191-200)

Link to original journal article

This was a RCT of rousuvastatin versus placebo in patients with sepsis and early ARDS (within 48 hours).  This study was stopped for futility after 745 patients showed no significant differences between active and control arms.

Final statement: Rosuvatatin showed no improvement in mortality for patients with sepsis and ARDS.

SIMVISTATIN IN THE ACUTE RESPIRATORY DISTRESS SYNDROME (McAuley Df et al. N Engl J Med. 2014 Oct 30: 371(18):1695-703)

Link to original journal article

This was a multicentre RCT of enteral simvastatin versus placebo in patients with early ARDS (within 48 hours).  540 patients were recruited to this study.  There was no significant difference in ventilator free days between active and control arms.  Additionally, there was no significant effect on hospital mortality.

Final statement: Simvastatin showed no reduction in ventilator free days in patients with ARDS.

THE ASSOCIATION BETWEEN ACUTE RESPIRATORY DISTRESS SYNDROME, DELIRIUM AND IN-HOSPITAL MORTALITY IN INTENSIVE CARE UNIT PATIENTS (Hseih SJ. Am J Respir Crit Care Med. 2015 Jan 1: 191(1):71-8)

Link to original journal article

This was a prospective observational cohort study at two hospitals in NYC.  564 ICU patients were assessed daily for the presence of delirium, coma and ARDS.  43% of patients were delirious at least one day during ICU with a median duration of 2 days.  Only 9% of patients were intubated with ARDS.  Prevalence of delirium was highest among patients with ARDS (73%) and ARDS was independently associated with delirium and hospital mortality.

Final statement: ARDS was found to be independently associated with delirium and hospital mortality.

TIMING OF LOW TIDAL VOLUME VENTILATION AND INTENSIVE CARE UNIT MORTALITY IN ACUTE RESPIRATORY DISTRESS SYNDROME (Needham DM et al.  Am J Respir Crit Care Med. 2015: 191(2) 177-185)

Link to original journal article

This was an observational cohort study of 482 patients with ARDS.  Low tidal volume ventilation was said to be £ 6.5ml/kg predicted body weight.  Within 12 hours of meeting ARDS criteria, 68% of patients received tidal volumes >6.5ml/kg, and within this group of patients only 56% of them ever received low tidal volume ventilation.  While adjusting for pH, respiratory rate and severity of hypoxemia, initial tidal volume was significantly associated with mortality. An increase of 1ml/kg initial tidal volume was associated with a 23% increase in mortality (p=0.008) and an increase of 1ml/kg after 12 hours of ARDS was associated with a 15% increase in mortality.

Final statement:  Initial tidal volumes >6.5ml/kg were associated with increased mortality in ARDS.

OXYGENATION RESPONSE TO POSITIVE END-EXPIRATORY PRESSURE PREDICTS MORTALITY IN ACUTE RESPIRATORY DISTRESS SYNDROME.  A SECONDARY ANALYSIS OF THE LOVS AND EXPRESS TRIALS (Gligher et al. Am J Respir Crit Car Med. 2014 Jul 1: 190(1):70-6)

Link to original journal article

This was a further analysis of the Lung open ventilation study (LOVS) and the ExPress study to look at the association of increased PEEP and mortality.  In the LOVS study, of those whose PEEP was increased, 48% had at least a 25mmHg increase in PaO2:FiO2 which was associated with a lower mortality, when compared to those who didn’t have an increase in PaO2:FiO2.  In the combined studies, oxygenation response to a change in PEEP was only significantly associated with mortality in patients with more severe ARDS.

Final statement: Improvement in oxygenation with increased PEEP was associated with lower mortality in ARDS.

DRIVING PRESSURE AND SURVIVIAL IN ACUTE RESPIRATORY DISTRESS SYNDROME (Amato et al. N Engl J Med. 2015 Feb 19: 372(8):747-55)

Link to original journal article

Driving pressure is defined as tidal volume divided by respiratory system compliance.  This was a secondary analysis of 3562 ARDS patients from nine randomised trials.  In this study the authors found that driving pressure was strongly associated with survival, a 7cm of H2O increase in driving pressure was associated with a 41% increased risk of mortality.  This risk was somewhat reduced, although still present, with low tidal volume ventilation.  Changes in tidal volume and PEEP were only associated with survival if mediating a change in driving pressure.

Final statement:  Driving pressure is strongly associated with survival/mortality.

ROUSUVASTATIN FOR SEPSIS-ASSOCIATED ACUTE RESPIRATORY DISTRESS SYNDROME (Truwit et al. N Engl J Med. 2014 Jun 5: 370 (23):2191-200)

Link to original journal article

This was a RCT of rousuvastatin versus placebo in patients with sepsis and early ARDS (within 48 hours).  This study was stopped for futility after 745 patients showed no significant differences between active and control arms.

Final statement: Rosuvatatin showed no improvement in mortality for patients with sepsis and ARDS.

SIMVISTATIN IN THE ACUTE RESPIRATORY DISTRESS SYNDROME (McAuley Df et al. N Engl J Med. 2014 Oct 30: 371(18):1695-703)

Link to original journal article

This was a multicentre RCT of enteral simvastatin versus placebo in patients with early ARDS (within 48 hours).  540 patients were recruited to this study.  There was no significant difference in ventilator free days between active and control arms.  Additionally, there was no significant effect on hospital mortality.

Final statement: Simvastatin showed no reduction in ventilator free days in patients with ARDS.

THE ASSOCIATION BETWEEN ACUTE RESPIRATORY DISTRESS SYNDROME, DELIRIUM AND IN-HOSPITAL MORTALITY IN INTENSIVE CARE UNIT PATIENTS (Hseih SJ. Am J Respir Crit Care Med. 2015 Jan 1: 191(1):71-8)

Link to original journal article

This was a prospective observational cohort study at two hospitals in NYC.  564 ICU patients were assessed daily for the presence of delirium, coma and ARDS.  43% of patients were delirious at least one day during ICU with a median duration of 2 days.  Only 9% of patients were intubated with ARDS.  Prevalence of delirium was highest among patients with ARDS (73%) and ARDS was independently associated with delirium and hospital mortality.

Final statement: ARDS was found to be independently associated with delirium and hospital mortality.

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