Multicenter Evaluation of a Novel Surveillance Paradigm for Complications of Mechanical Ventilation

Abstract

BackgroundVentilator-associated pneumonia (VAP) surveillance is time consuming, subjective, inaccurate, and inconsistently predicts outcomes. Shifting surveillance from pneumonia in particular to complications in general might circumvent the VAP definition's subjectivity and inaccuracy, facilitate electronic assessment, make interfacility comparisons more meaningful, and encourage broader prevention strategies. We therefore evaluated a novel surveillance paradigm for ventilator-associated complications (VAC) defined by sustained increases in patients' ventilator settings after a period of stable or decreasing support.MethodsWe assessed 600 mechanically ventilated medical and surgical patients from three hospitals. Each hospital contributed 100 randomly selected patients ventilated 2–7 days and 100 patients ventilated >7 days. All patients were independently assessed for VAP and for VAC. We compared incidence-density, duration of mechanical ventilation, intensive care and hospital lengths of stay, hospital mortality, and time required for surveillance for VAP and for VAC. A subset of patients with VAP and VAC were independently reviewed by a physician to determine possible etiology.ResultsOf 597 evaluable patients, 9.3% had VAP (8.8 per 1,000 ventilator days) and 23% had VAC (21.2 per 1,000 ventilator days). Compared to matched controls, both VAP and VAC prolonged days to extubation (5.8, 95% CI 4.2–8.0 and 6.0, 95% CI 5.1–7.1 respectively), days to intensive care discharge (5.7, 95% CI 4.2–7.7 and 5.0, 95% CI 4.1–5.9), and days to hospital discharge (4.7, 95% CI 2.6–7.5 and 3.0, 95% CI 2.1–4.0). VAC was associated with increased mortality (OR 2.0, 95% CI 1.3–3.2) but VAP was not (OR 1.1, 95% CI 0.5–2.4). VAC assessment was faster (mean 1.8 versus 39 minutes per patient). Both VAP and VAC events were predominantly attributable to pneumonia, pulmonary edema, ARDS, and atelectasis.ConclusionsScreening ventilator settings for VAC captures a similar set of complications to traditional VAP surveillance but is faster, more objective, and a superior predictor of outcomes.

Should Ventilator-Associated Events become a Quality Indicator for ICUs?

“…At least 4 studies have evaluated consecutive subjects with VAEs to try to identify the clinical conditions that led to increases in ventilator support. 22,25,28,30 Findings from these studies are similar. The majority of VAEs are caused by pneumonia, fluid overload, atelectasis, and/or ARDS.…”

“…They affect 5-10% of patients and have consistently been associated with longer duration of mechanical ventilation, longer hospital lengths of stay, more antibiotic usage, and higher mortality rates. [22][23][24][25][26][27][28][29][30][31][32] Multiple studies suggest that patients who develop VAEs are approximately twice as likely to die compared with similar patients who do not develop VAEs. [22][23][24][25][26][27][28][29][30][31][32] …”

“…The relative frequency of these conditions varies between studies, but generally pneumonia accounts for about 20 -40% of VAEs, fluid overload for 30 -40%, atelectasis for 10 -20%, and ARDS for 10 -20%. 22,25,28,30 Knowing which conditions typically trigger VAEs helps to inform the development of strategies to prevent VAEs. Clinicians can intuit prevention strategies based on their prior experience with these 4 conditions as well as draw upon an increasing number of studies that identify specific risk factors for VAEs and demonstrate strategies that can decrease the frequency of VAEs.…”

Intermittent recruitment with high-frequency oscillation/tracheal gas insufflation in acute respiratory distress syndrome

“…Indeed, although pre-enrolment DMV exceeded 7 days [33] in just 12 (9.6%) patients (eight in the HFO-TGI group), the results of a recent multicentre trial imply that any difference in the overall management strategy of early ARDS might affect results for mortality [34].…”

Complications of Mechanical Ventilation — The CDC's New Surveillance Paradigm

“…3,4 These events appear to be highly meaningful: studies from the United States, Canada, Australia, and Italy have consistently shown strong associations between VACs and prolonged length of stay in the ICU and between VACs and higher mortality rates. [3][4][5] These events are also potentially actionable: there is a great deal of existing literature on how to prevent and manage these four conditions. Subsequent tiers of ventilatorassociated events are designed to identify the subset of VACs that are infection-related and those that might indeed be pneumonias.…”