Chest CT features are associated with poorer quality of life in acute lung injury survivors

Abstract

Objectives: Despite decreasing mortality rates in acute lung injury, studies of long-term physical function in acute lung injury survivors have consistently reported poorer quality of life persisting years into recovery for reasons that are not completely understood. We sought to determine if pulmonary dysfunction is independently associated with functional impairment among acute lung injury survivors and to determine if high-resolution computed tomography could be used to predict its development.

Design: Secondary analysis of data from a randomized controlled trial in acute lung injury.

Setting: ICUs at three academic medical centers.

Patients: Patients diagnosed with acute lung injury who had high-resolution computed tomography scans performed at 14 and/or 180 days after diagnosis.

Interventions: None.

Measurements and main results: An objective radiologic scoring system was used to quantify patterns present on chest high-resolution computed tomography obtained at 14 and 180 days in patients with acute lung injury. These scores were correlated in univariable and multivariable analyses with pulmonary function testing and quality of life survey data obtained at 180 days. Eighty-nine patients had evaluable data at day 14, and 47 at 180 days. At 180 days, increased radiologic scores for reticulation were associated with a decreased total lung capacity, forced vital capacity, and diffusing capacity for carbon monoxide (p values all < 0.002). Decrements in quality of life attributable to pulmonary dysfunction were most strongly associated with higher radiologic scores. Additionally, radiologic scores at 14 days independently predicted poorer quality of life at 180 days, accounting for age, severity of illness, pneumonia as the acute lung injury risk factor, and length of time on mechanical ventilation.

Conclusions: Among survivors of acute lung injury, increasing chest high-resolution computed tomography involvement correlated with restrictive physiology and poorer health-related quality of life, implicating pulmonary dysfunction as a potential contributor to activity limitation in these patients.

Figure 1

Derivation of study cohort from parent trial. *6 subjects had pulmonary function testing performed at 180 days, but did not undergo an HRCT of the chest at 14 days while inpatients. Eighty patients in the included group were randomized to study drug (43 GMCSF/37 placebo). ALI=acute lung injury; GMCSF=granulocyte macrophage colony stimulating factor; HRCT=high resolution computed tomography; PFTs=pulmonary function testing; HRQoL=health-related quality of life

Figure 2

Chest high resolution CT Scores for ALI patients in the cohort. At 14 days, scores for GGO pattern were the most elevated, while at 180 days, reticulation and GGO scores did not differ significantly. For all three patterns, scores decreased significantly over time (p<0.0001). GGO=ground glass opacification; IPO=intense parenchymal opacification. Bars=means of data; black lines=standard deviation.

Figure 3

Examining the relationship between 180 day high resolution CT (HRCT) scores and health-related quality of life measurements revealed that as HRCT scores increased, quality of life was adversely affected, as indicated by lower short form (SF)-36 scores and higher St. George’s Respiratory Questionnaire (SGRQ) scores. (3a) HRCT reticulation score and SF-36 physical health subtotal; (3b) HRCT reticulation score and SGRQ Total Score.

Figure 4

180 day percent predicted total lung capacity versus 14 day chest high resolution CT scores. Examining the relationship between 14 day high resolution CT (HRCT) scores for (3a) reticulation, (3b) ground glass opacification (GGO), (3c) intense parenchymal opacifiation (IPO), and (3d) overall with the % predicted total lung capacity (TLC) at 180 days after ALI diagnosis revealed significant inverse associations. The HRCT overall score was calculated by totaling scores for reticulation, GGO, and IPO.

Figure 5

Examining the relationship between 14 Day high resolution CT (HRCT) scores and 180 day health-related quality of life measurements revealed that higher HRCT scores correlated with poorer quality of life. (4a) HRCT reticulation score and short form (SF)-36 physical health subtotal scores; (4b) HRCT reticulation score and St. George’s Respiratory Questionnaire (SGRQ) Total Score.