A104-01 Large Scale Implementation of Multi-center Collection of Respiratory Samples From Heat-Moisture Exchange (HME) Filters in the ARDS Pneumonia Sepsis (APS) Consortium

Rationale Fluid from Heat-Moisture Exchange (HME) filters from invasively ventilated patients accurately represents the biology of the distal airspace and is a potentially powerful tool for non-invasive, serial sampling of the lung. The ARDS, Pneumonia, Sepsis (APS) Consortium implemented collection of fluid from HME filters as part of a 21-site observational cohort study. Methods Standardized methods for HME fluid collection based on published studies were disseminated to all study sites. Site investigators and coordinators were trained on HME collection and processing procedures during virtual training sessions. Study subjects were eligible for HME collection if they were mechanically ventilated and passed a safety screen. Data from the first 500 subjects was analyzed to provide a preliminary assessment of feasibility in collecting HME filter fluid in the population. Results On study day 1, 207 of 500 subjects were mechanically ventilated and eligible for HME collection. Of these, 132 (64%) had HME filters collected. Reasons for non-collection of HME included clinical care team declined collection (20 instances), participant/surrogate declined collection (13 instances), subject failed safety screen (28 instances), and unknown (14 instances). Collection rates were lower on subsequent study days (day 2, 52%; day 4, 55%; day 6, 51% of patients who remain intubated and eligible) and varied by individual study site from 14%-100%. In total, 318 HME samples were collected across all sites and days. HME fluid was stored in 200ul aliquots for a maximum of 10 aliquots per timepoint. Among the 318 filters,10 aliquots were collected in 29% and there was an even distribution of 1 to 9 aliquots (8% each) among the remaining 225 HMEs. No adverse events occurred related to fluid collection. Discussion In this large, multi-center observational cohort study, we demonstrated the feasibility of implementation of HME filter collection across multiple study sites, most of which had not previously collected HME filters. HME filters were collected on the majority of intubated subjects on each study day. Fluid volume collected, as measured by number of aliquots, varied considerably (from 1-10 x 200 microliter aliquots), but all HMEs generated at least 200 ul of fluid. Based on these encouraging observations in the first 500 patients, we anticipate that APS will include HME fluid from over 1000 mechanically ventilated patients once the full 4000 patient enrollment is complete. This will represent a novel and valuable resource for studying airspace biology in ARDS, pneumonia and sepsis.