Similar to the 2011 workshop, a Delphi method was used to solicit measurements of experimental ALI (Figure 2 ). In Round 1 (Table E2), the 50 participants were asked to complete an electronic survey, wherein they stated all the measurements that they thought would be helpful to assess 1) histological evidence of tissue injury, 2) alteration of the alveolar–capillary barrier, 3) presence of an inflammatory response, and 4) evidence of physiologic dysfunction. Here, we refer to “features” as a measurement or group of measurements that address a specific component of a domain. Additionally, we asked the participants whether a time criterion should be included in the definition of experimental ALI and, if yes, to suggest a time. This question was asked based on feedback from workshop participants that the time criterion of 24 hours was too short for some models of lung injury (e.g., viral pneumonia) (17 (link)).
All the responses obtained as a part of the first round were collated by the domain leads and organized into a questionnaire for Round 2 (Table E3). Specifically, in Round 2, participants were provided with a list of all the measurements obtained from Round 1 under each of the four original domains in the 2011 workshop report. Participants were asked to rate each measurement according to importance using a scale of 0–5 (0 = minimal importance, 5 = maximal importance). As a part of the “histological evidence of tissue injury” domain, measurements were grouped by anatomical location: 1) alveolar spaces, 2) alveolar epithelium, 3) vasculature, 4) alveolar septae, and 5) interstitium. As a part of the “alteration of the alveolar–capillary barrier” domain, measurements were grouped under 1) endothelial injury or dysfunction, 2) epithelial injury or dysfunction, 3) lung edema, and 4) transfer of plasma or lung constituents across the barrier. As a part of the “presence of an inflammatory response” domain, measurements were grouped under 1) soluble mediator profiles, 2) inflammatory cellular composition and characteristics, and 3) consequences of inflammation. Finally, as a part of the “evidence of physiologic dysfunction” domain, measurements were grouped under 1) gas exchange, 2) lung mechanics, 3) vital signs, and 4) other aspects of the physiological domain.
In Round 3, answers to the questions from Round 2 were collated and presented to the participants (Table E4). Participants were asked to choose the top 4–5 features that they considered “most relevant” to measure each domain. Those features selected as “most relevant” by 30% or more of the respondents were considered “relevant” for that domain for the purpose of this workshop. We noted that a 30% cutoff resulted in at least five measurements ranked as “most relevant” in each of the four domains by the panelists. This approach would maximize the numbers of relevant measurements available to the community and maintain consistency in the number of relevant measurements across the domains, thereby increasing flexibility in application to many experimental ALI models.
All the responses obtained as a part of the first round were collated by the domain leads and organized into a questionnaire for Round 2 (Table E3). Specifically, in Round 2, participants were provided with a list of all the measurements obtained from Round 1 under each of the four original domains in the 2011 workshop report. Participants were asked to rate each measurement according to importance using a scale of 0–5 (0 = minimal importance, 5 = maximal importance). As a part of the “histological evidence of tissue injury” domain, measurements were grouped by anatomical location: 1) alveolar spaces, 2) alveolar epithelium, 3) vasculature, 4) alveolar septae, and 5) interstitium. As a part of the “alteration of the alveolar–capillary barrier” domain, measurements were grouped under 1) endothelial injury or dysfunction, 2) epithelial injury or dysfunction, 3) lung edema, and 4) transfer of plasma or lung constituents across the barrier. As a part of the “presence of an inflammatory response” domain, measurements were grouped under 1) soluble mediator profiles, 2) inflammatory cellular composition and characteristics, and 3) consequences of inflammation. Finally, as a part of the “evidence of physiologic dysfunction” domain, measurements were grouped under 1) gas exchange, 2) lung mechanics, 3) vital signs, and 4) other aspects of the physiological domain.
In Round 3, answers to the questions from Round 2 were collated and presented to the participants (Table E4). Participants were asked to choose the top 4–5 features that they considered “most relevant” to measure each domain. Those features selected as “most relevant” by 30% or more of the respondents were considered “relevant” for that domain for the purpose of this workshop. We noted that a 30% cutoff resulted in at least five measurements ranked as “most relevant” in each of the four domains by the panelists. This approach would maximize the numbers of relevant measurements available to the community and maintain consistency in the number of relevant measurements across the domains, thereby increasing flexibility in application to many experimental ALI models.