Lipid‐Laden Macrophage Index as a Diagnostic Tool for Pediatric Aspiration: A Systematic Review

OBJECTIVE: Lipid‐laden macrophage index (LLMI) has been proposed as a marker for aspiration on bronchoalveolar lavage. It has also been studied as a marker for gastroesophageal reflux and other pulmonary diseases. This review aims to determine the clinical correlation between LLMI and pediatric aspiration. DATA SOURCES: PubMed (MeSH search), Scopus, and Cochrane Central Register of Controlled Trials (CENTRAL) portals through December 17th, 2020. REVIEW METHODS: Preferred Reporting Items for Systematic Review and Meta‐Analysis criteria were followed, and a quality assessment of included studies was performed using the Methodological Index for Non‐Randomized Studies. Search criteria included all occurrences in the title or abstract of the terms “pulmonary aspiration” and “alveolar macrophages.” RESULTS: Five studies describing 720 patients met inclusion, 3 retrospective case‐control studies, and 2 prospective observational studies. Four studies suggested a link between elevated LLMI and aspiration, and 1 found no association. Control groups varied and included healthy nonaspirators to nonaspirators with other pulmonary diseases. Diagnosis of aspiration was not standardized across the studies. Three papers proposed cutoff values for LLMI, all different. CONCLUSION: The existing literature indicates that LLMI is not a sensitive or specific marker for aspiration. Further study is needed to define the utility of LLMI in pediatric aspiration.