Evaluation of the effect of diagnostic methodology on the reported incidence of ventilator-associated pneumonia

Abstract

Background: The optimal method for diagnosing ventilator-associated pneumonia (VAP) is controversial and its effect on reported incidence uncertain. This study aimed to model the impact of using either endotracheal aspirate or bronchoalveolar lavage on the reported incidence of pneumonia and then to test effects suggested from theoretical modelling in clinical practice. Methods: A three-part single-centre study was undertaken. First, diagnostic performance of aspirate and lavage were compared using paired samples from 53 patients with suspected VAP. Secondly, infection surveillance data were used to model the potential effect on pneumonia incidence and antibiotic use of using exclusively aspirate or lavage to investigate suspected pneumonia (643 patients; 110 clinically suspected pneumonia episodes). Thirdly, a practice change initiative was undertaken to increase lavage use; pneumonia incidence and antibiotic use were compared for the 12 months before and after the change. Results: Aspirate overdiagnosed VAP compared with lavage (89% vs 21% of clinically suspected cases, p,0.0001). Modelling suggested that changing from exclusive aspirate to lavage diagnosis would decrease reported pneumonia incidence by 76% (95% CI 67% to 87%) and antibiotic use by 30% (95% CI 20% to 42%). After the practice change initiative, lavage use increased from 37% to 58%. Although clinically suspected pneumonia incidence was unchanged, microbiologically confirmed VAP decreased from 18 to 9 cases per 1000 ventilator days (p = 0.001; relative risk reduction 0.61 (95% CI 0.46 to 0.82)), and mean antibiotic use fell from 9.1 to 7.2 antibiotic days (21% decrease, p = 0.08). Conclusions: Diagnostic technique impacts significantly on reported VAP incidence and potentially on antibiotic use.

Ventilator-associated pneumonia is an important risk factor for mortality after major cardiac surgery

“…Most of these studies have included patients with diverse pathologies (medical, surgical, trauma patients, etc), and this makes drawing conclusions difficult. In addition, the problem is further complicated by the different criteria and methods used to diagnose VAP, which in turn makes the comparison of results even more problematic [37].…”

The Impact of Hospital-Wide Use of a Tapered-Cuff Endotracheal Tube on the Incidence of Ventilator-Associated Pneumonia

“…12 Several studies have suggested that publicly reported VAP rates may not accurately reflect clinical VAP. 20,21 However, a study of patients in our institution indicated that, while specific patients may differ, the rates of pneumonia were similar whether bronchoscopic or National Healthcare Safety Network criteria were used. 22 While this study was designed to be powered to detect a 50% reduction in the VAP rate, this was predicated on a historical VAP rate of 5.8 Ϯ 1.47 per 1,000 ventilator days, present in early 2010 during study planning.…”

Monitorowanie zapalenia płuc związanego z wentylacją mechaniczną według projektu INICC — doświadczenia jednego ośrodka

“…In one of the studies, the patients diagnosed by BAL had a lower number of confirmed VAP (6.1 vs. 25.5/1000 ventilation days) compared to those diagnosed with non-protective aspiration, which was characterised by 90% sensitivity and only 14% specificity [24]. The literature data indicate that VAP prophylaxis, in the form of the ventilation bundle, can result in notable effects, i.e., decreased incidence [3,15,23,25]; however, studies confirming the lack of infections of this type in a given period are sparse [17,26].…”