Objective: Tracheal intubation and mechanical ventilation provide essential support for patients with respiratory failure, but the course of mechanical ventilation may be complicated by adverse ventilator-associated events (VAEs), which may or may not be associated with infection. We sought to understand how the frequency of subglottic suction, an indicator of the quantity of sputum produced by ventilated patients, relates to the onset of all VAEs and infection-associated VAEs. Design: We performed a case-crossover study including 87 patients with VAEs, and we evaluated 848 days in the pre-VAE period at risk for a VAE. Setting and participants: Critically ill patients were recruited from the medical intensive care unit of an academic medical center. Methods: We used the number of as-needed subglottic suctioning events performed per calendar day to quantify sputum production, and we compared the immediate pre-VAE period to the preceding period. We used CDC surveillance definitions for VAE and to categorize whether events were infection associated or not. Results: Sputum quantity measured by subglottic suction frequency is greater in the period immediately prior to VAE than in the preceding period. However, it does not discriminate well between infection-associated VAEs and VAEs without associated infection. Conclusions: Subglottic suction frequency may serve as a valuable marker of sputum quantity, and it is associated with risk of a VAE. However, our results require validation in a broader population of mechanically ventilated patients and intensive care settings.

BackgroundMechanical ventilation is a life-sustaining therapy for critically ill patients, but is associated with increased hospital costs and risk for significant complications with poor outcomes. Adverse ventilator-associated events (VAEs) can be broadly divided into infectious (infectious ventilator-associated complication (IVAC) or ventilator-associated pneumonia (VAP)) and non-infectious (ventilator-associated complication (VAC)) types. We sought to identify factors that predict both types, and factors that discriminate risk for infectious vs. noninfectious VAE, using electronic medical record (EMR) data available prior to index event.MethodsWe evaluated 90 consecutive adverse VAEs in the medical intensive care unit of an academic medical center (January 1, 2013–June 30, 2016) to determine prior patient and care factors that discriminate risk for incident VAE. VAE were defined by surveillance criteria from the CDC. Patient and care data were extracted via the EMR.ResultsA generalized linear mixed effects model found an increase of 1.1 (95% CI 0.53–1.7) subglottic suction events per day (SS/day) on the day before VAE diagnosis, relative to the 4 prior days. Of the 90 VAE included in the study, 41 were infectious (IVAC or VAP), and 49 were labeled ventilator-associated condition (VAC). In the IVAC/VAP group, mean SS/day was 8.0 on the day of VAE diagnosis, 7.5 one day prior, and 6.2 two days prior, compared with 6.6, 6.4, and 5.5 SS/day in the VAC group. Change in antibiotic prescription (87.8% (36) of patients in the IVAC/VAP group vs. 46.9% (23) in the VAC group) (P = 0.023) and acute liver injury (mean AST and ALT 52.9 and 43.6 3 days before IVAC/VAP vs. 1,035.4 and 523.9 before VAC) also differed between the groups (P = 0.0095 and 0.0025).ConclusionIncreased daily subglottic suctioning predicts both non-infectious and infectious VAE, but the observed increase is greater prior to IVAC/VAP. Change in antibiotic prescription and acute liver injury also discriminated IVAC/VAP from non-infectious VAE in this small cohort.Disclosures All authors: No reported disclosures.

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