Role of galactomannan determinations in bronchoalveolar lavage fluid samples from critically ill patients with chronic obstructive pulmonary disease for the diagnosis of invasive pulmonary aspergillosis: a prospective study

Hangyong He,Qingyuan Zhan,Fang Li,Bing Sun,Lin Ding

doi:10.1186/cc11443

Abstract

IntroductionCritically ill chronic obstructive pulmonary disease (COPD) patients are at particular risk of invasive pulmonary aspergillosis (IPA). Our aims were to determine whether bronchoalveolar lavage fluid (BALF) galactomannan (GM) has a higher sensitivity and specificity than serum GM or lower respiratory tract (LRT) sample culture. Furthermore, we aimed to investigate what the optimal cut-off value would be for BALF GM.MethodsIn this prospective single-center study, BALF and serum samples were collected from critically ill COPD patients on the first day of their intensive care unit admission.ResultsOf 50 critically ill COPD patients admitted, BALF and serum samples were collected in 34 patients. According to the receiver operating characteristics (ROC) curve, an optical density (OD) ratio of 0.8 was chosen as the cut-off value for GM in BALF. Compared to serum GM and LRT Aspergillus isolation, BALF GM yield a better sensitivity, specificity, positive and negative predictive values of 88.9%, 100%, 100% and 94.4%, respectively. Areas under the ROC curve were 0.912 (95%CI, 0.733 to 0.985) for BALF GM, and 0.879 (95%CI, 0.691 to 0.972) for serum GM results from the first day of ICU admission. Pairwise comparison of ROC curves showed P = 0.738. The OD ratio of BALF GM in IPA patients were significantly higher than those of non-IPA patients (2.88 ± 2.09 versus 0.49 ± 0.19, P = 0.009), and the OD ratio of BALF GM was significantly higher than serum GM in IPA patients (2.88 ± 2.09 versus 0.87 ± 0.47, P = 0.023). Positive BALF GM was seen earlier than LRT secretion culture (1 day versus 3.8 days).ConclusionsCompared to serum GM and LRT Aspergillus isolation, BALF GM seems to have a better sensitivity in the diagnosis of IPA in critically ill COPD patients. The ROC curve suggests a possible cut-off value of 0.8 for GM from BALF specimens in critically ill COPD patients.

Highlights

Ill chronic obstructive pulmonary disease (COPD) patients are at particular risk of invasive pulmonary aspergillosis (IPA)
Our study revealed that, compared to lower respiratory tract (LRT) Aspergillus isolation and serum GM, bronchoalveolar lavage fluid (BALF) GM might have a better sensitivity and a same specificity, and may improve the diagnosis of IPA in critically ill COPD patients
Compared to serum GM and LRT Aspergillus isolation, BALF GM appears to have a higher sensitivity in the early diagnosis of IPA in critically ill COPD patients

Summary

Introduction

Ill chronic obstructive pulmonary disease (COPD) patients are at particular risk of invasive pulmonary aspergillosis (IPA). Our aims were to determine whether bronchoalveolar lavage fluid (BALF) galactomannan (GM) has a higher sensitivity and specificity than serum GM or lower respiratory tract (LRT) sample culture. Data on BALF GM for IPA diagnosis in critically ill COPD patients are limited [21] and, so far, no cut-off value for BALF GM has been established for the diagnosis of IPA in this population. The aim of this prospective single center study is to determine whether BALF GM has a higher sensitivity and specificity than serum GM or lower respiratory tract (LRT) culture. We aimed to investigate what the optimal cut-off value would be for BALF GM

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