Epidemiology of Ventilator-acquired Pneumonia Based on Protected Bronchoscopic Sampling

Abstract

We performed a prospective observational cohort study of the epidemiology and etiology of nosocomial pneumonia in 358 medical ICU patients in two university-affiliated hospitals. Protected bronchoscopic techniques (protected specimen brush and bronchoalveolar lavage) were used for diagnosis to minimize misclassification. Risk factors for ventilator-associated pneumonia were identified using multiple logistic regression analysis. Twenty-eight cases of pneumonia occurred in 358 patients for a cumulative incidence of 7.8% and incidence rates of 12.5 cases per 1, 000 patient days and 20.5 cases per 1,000 ventilator days. Staphylococcus aureus, Streptococcus pneumoniae, Pseudomonas aeruginosa, and Hemophilus species made up 65% of isolates from the lower respiratory tract, whereas only 12.5% of isolates were enteric gram-negative bacilli. Daily surveillance cultures of the nares, oropharynx, trachea, and stomach demonstrated that tracheal colonization preceded ventilator-associated pneumonia in 93.5%, whereas gastric colonization preceded tracheal colonization for only four of 31 (13%) eventual pathogens. By multiple logistic regression, independent risk factors for ventilator- associated pneumonia were admission serum albumin <= 2.2 g/dl (odds ratio [OR] 5.9; 95% confidence interval [CI] 2.0-17.6; p = 0.0013), maximum positive end-expiratory pressure >= 7.5 cm H2O (OR, 4.6; 95% CI, 1.4 to 15.1; p = 0.012), absence of antibiotic therapy (OR, 6.7; 95% CI, 1.8 to 25.3; p = 0.0054), colonization of the upper respiratory tract by respiratory gram-negative bacilli (OR, 3.4; 95% CI, 1.1 to 10.1; p = 0.028), pack-years of smoking (OR, 2.3 for 50 pack-years; 95% CI, 1. 2 to 4.2; p = 0.012), and duration of mechanical ventilation (OR, 3. 4 for 14 d; 95% CI, 1.5 to 7.8; p = 0.0044). Several of these risk factors for ventilator-associated pneumonia appear amenable to intervention.

Amoeba-Resisting Bacteria and Ventilator-Associated Pneumonia

“…Among the 30 patients, VAP occurred frequently (56.6%) and was associated with hospitalization duration, as previously reported ( 30 , 31 ). Of the patients with VAP, 58.8% seroconverted to amoeba-associated bacteria, as compared to 15.4% of the remaining 13 patients (p=0.026).…”

Nosocomial Infections in the General Pediatric Wards of a Hospital in Turkey

“…The VAP frequency was 35.5 cases per 1,000 ventilator days in our study. The incidence rate of VAP that was found in our study was higher than that of other studies (4,(9)(10)(11)(12)(13). This was thought to be a result of the treatment of critically ill patients with mechanical ventilators in general pediatric wards without a sufficient number of medical staff and isolation conditions because of the absence of a PICU in the hospital.…”

The Vexing Problem of Ventilator-Associated Pneumonia: Observations on Pathophysiology, Public Policy, and Clinical Science

“…Admission serum albumin below 2.2 g/dL is associated with a 6-fold higher incidence of VAP. 124 Cumulative energy deficits among mechanically ventilated medical ICU subjects have been associated with increasing risk of VAP from 3-to 16-fold as energy deficits rise from 30 to 67%. 125 …”