Authors: Roy G Brower Massimo Antonelli
Publish Date: 2016/03/01
Volume: 42, Issue: 5, Pages: 772-774
Abstract
The incidence of acute respiratory distress syndrome ARDS is variable depending on definitions sampling techniques and geographic region but it is almost always a morbid and frequently fatal disorder Survivors frequently suffer from debilitating sequelae 1 Most clinical trials of promising treatments for ARDS failed to demonstrate beneficial effectsOne possible reason for these disappointing trials is that the experimental therapies were administered after the lungs had been affected by severe inflammatory processes These therapies may be more effective if they are administered earlier in patients’ conditions such as severe sepsis or trauma before onset of ARDS An example of a successful prevention approach is the use of lower tidal volumes in patients who did not have ARDS when mechanical ventilation was initiated This was associated with a decrease in the frequency of hospitalacquired ARDS 2The first step to prevention of ARDS is to identify patients most likely to benefit from the prophylactic interventions Several recent prevention studies selected patients undergoing surgical procedures in which there was substantial risk of postoperative ARDS such as cardiac or esophageal surgeries 3 4 In these studies the preventive interventions were delivered perioperatively before onset of ARDSThe lung injury prediction score LIPS 5 is a promising tool for risk stratification at hospital admission of patients without ARDS To develop this prediction model 5584 patients with sepsis shock pancreatitis pneumonia aspiration highrisk trauma and highrisk surgery were evaluated after hospital admission The model included the identification of the risk modifiers alcohol abuse obesity chemotherapy hypoalbuminemia RR 30 SpO2 95 FiO2 35 pH 735 and diabetes mellitus that allowed a better stratification of the atrisk population A LIPS ≥4 points had a sensitivity of 69 and specificity of 78 for identifying patients who would develop ARDS after admission The validity of LIPS for identifying patients at high risk for ARDS in the emergency department was confirmed in a recent external cohort 6 The LIPS was used in the recently concluded Lung Injury Prevention StudyAspirin LIPSA 7Another tool for identifying patients at risk for ARDS is the early acute lung injury score EALI 8 An EALI score ≥2 had a sensitivity of 89 specificity of 75 and positive predictive value of 53 However the EALI score has not been validated in an external cohort or used in a clinical trial for ARDS preventionA reliable biomarkerdriven approach could be of great value to identify highrisk patients or to identify patients most likely to benefit from a new intervention The combination of plasma angiopoietin2 with LIPS was a better predictor for subsequent development of ARDS than either LIPS or angiopoietin2 alone 6The timing of preventive interventions for ARDS depends largely on whether the intervention is intended as primary secondary or tertiary prevention Primary prevention aims to prevent disease or injury before it occurs For ARDS this is only feasible in patients in whom the acute injury predisposing to ARDS can be predicted such as those undergoing elective highrisk surgery or patients who need multiple transfusions 9 10Secondary prevention aims to reduce the impact of a disease or injury such as sepsis or aspiration that has already occurred The period between a patient’s hospital admission and when ARDS develops often occurs in the emergency department or on the inpatient ward Many hospitalized patients with sepsis and other risk factors for ARDS are managed outside of the ICU 11 Thus screening for ARDS prevention trials must occur outside of the ICU
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