Fibroproliferative changes on high-resolution CT in the acute respiratory distress syndrome predict mortality and ventilator dependency: a prospective observational cohort study

Abstract

ObjectivesTo examine whether the extent of fibroproliferative changes on high-resolution CT (HRCT) scan influences prognosis, ventilator dependency and the associated outcomes in patients with early acute respiratory distress syndrome (ARDS).DesignA prospective observational cohort study.SettingIntensive care unit in a teaching hospital.Participants85 patients with ARDS who met American-European Consensus Conference Criteria and eligible criteria.InterventionsHRCT scans were performed and prospectively evaluated by two independent observers on the day of diagnosis and graded into six findings according to the extent of fibroproliferation. An overall HRCT score was obtained by previously published method.Primary and secondary outcomesThe primary outcome was 60-day mortality. Secondary outcomes included the number of ventilator-free days, organ failure-free days, the incidence of barotraumas and the occurrence of ventilator-associated pneumonia.ResultsHigher HRCT scores were associated with statistically significant decreases in organ failure-free days as well as ventilator-free days. Multivariate Cox proportional hazards model showed that the HRCT score remained an independent risk factor for mortality (HR 1.20; 95% CI 1.06 to 1.36; p=0.005). Multivariate analysis also revealed that the CT score had predictive value for ventilator weaning within 28 days (OR 0.63; 95% CI 0.48 to 0.82; p=0.0006) as well as for an incidence of barotraumas (OR 1.61; 95% CI 1.08 to 2.38; p=0.018) and for an occurrence of ventilator-associated pneumonia (OR 1.46; 95% CI 1.13 to 1.89; p=0.004). A HRCT score <210 enabled prediction of 60-day survival with 71% sensitivity and 72% specificity and of ventilator-weaning within 28 days with 75% sensitivity and 76% specificity.ConclusionsPulmonary fibroproliferation assessed by HRCT in patients with early ARDS predicts increased mortality with an increased susceptibility to multiple organ failure, including ventilator dependency and its associated outcomes.

N-Acetylcysteine Inhibits Ventilation-Induced Collagen Accumulation in the Rat Lung

“…These findings all suggest that mechanical ventilation can lead to pulmonary fibroproliferative responses. Unlike previous understanding, there is clear evidence of fibroproliferative responses such as increased synthesis of lung collagen, which leads to lung repair and fibrosis (Suki et al 2005), in the earliest stages of ARDS and its correlation with a poor outcome (Marshall et al 2000;Ichikado et al 2012). Hence, mechanical ventilation may have contributed to the early collagen synthesis during the course of ARDS.…”

“…The concentration of PC III, a byproduct of type III collagen synthesis is higher in serum and lung lavage fluids in ARDS patients compared with control patients at 24 h (Marshall et al 2000), and 47% of patients had evidence of fibroproliferation assessed by high-resolution computed tomography (HRCT) on the first day of ARDS (Ichikado et al 2012). The elevated level of PC III and pulmonary fibroproliferation in early ARDS are predictive of increased mortality and poor outcome (Chesnutt et al 1997;Marshall Fig.…”

Detection of Fibroproliferation by Chest High-Resolution CT Scan in Resolving ARDS

“…21,24,25 Our fi ndings suggest the potential of early HRCT scan evaluation in patients with ARDS with the poorest lung compliance to identify individuals who may be at risk for complications related to excessive fi broproliferation. 6 Emerging evidence suggests that HRCT scan scores measured very early (within days) aft er ARDS diagnosis using validated methods 7,8 may be helpful in prognosticating short-term outcomes, illustrated in a prospective observational study 9 in which evidence for chest HRCT scan fi broproliferation present on the fi rst day of ARDS diagnosis was associated with 60-day mortality. However, our recent investigations suggest that chest HRCT scans obtained at 14 days post ARDS diagnosis identifi es a subset of patients who will have persistent radiographic fi broproliferation much later, at 180 days, and also poorer pulmonary-specifi c quality of life.…”

“…Previous investigations have used chest high-resolution CT (HRCT) scans as a tool in very early ARDS ( , 1 week) [7][8][9] to identify patients with fi broproliferative radiologic abnormalities who are likely to suff er poorer short-term outcomes, such as mortality. However, studies to systematically assess fi broproliferation via HRCT scan during resolving ARDS ( .…”

Imaging of Thoracic Trauma

“…More commonly, CT can be useful in assessing the prognosis of patients with already established diffuse alveolar damage. Development of fibroproliferative changes on CT predicts prolonged mechanical ventilation, the development of barotrauma and ventilator-associated pneumonia [27].…”