Diagnosis of ventilator-associated pneumonia in critically ill adult patients—a systematic review and meta-analysis

Abstract

The accuracy of the signs and tests that clinicians use to diagnose ventilator-associated pneumonia (VAP) and initiate antibiotic treatment has not been well characterized. We sought to characterize and compare the accuracy of physical examination, chest radiography, endotracheal aspirate (ETA), bronchoscopic sampling cultures (protected specimen brush [PSB] and bronchoalveolar lavage [BAL]), and CPIS > 6 to diagnose VAP. We searched six databases from inception through September 2019 and selected English-language studies investigating accuracy of any of the above tests for VAP diagnosis. Reference standard was histopathological analysis. Two reviewers independently extracted data and assessed study quality. We included 25 studies (1639 patients). The pooled sensitivity and specificity of physical examination findings for VAP were poor: fever (66.4% [95% confidence interval [CI]: 40.7-85.0], 53.9% [95% CI 34.5-72.2]) and purulent secretions (77.0% [95% CI 64.7-85.9], 39.0% [95% CI 25.8-54.0]). Any infiltrate on chest radiography had a sensitivity of 88.9% (95% CI 73.9-95.8) and specificity of 26.1% (95% CI 15.1-41.4). ETA had a sensitivity of 75.7% (95% CI 51.5-90.1) and specificity of 67.9% (95% CI 40.5-86.8). Among bronchoscopic sampling methods, PSB had a sensitivity of 61.4% [95% CI 43.7-76.5] and specificity of 76.5% [95% CI 64.2-85.6]; while BAL had a sensitivity of 71.1% [95% CI 49.9-85.9] and specificity of 79.6% [95% CI 66.2-85.9]. CPIS > 6 had a sensitivity of 73.8% (95% CI 50.6-88.5) and specificity of 66.4% (95% CI 43.9-83.3). Classic clinical indicators had poor accuracy for diagnosis of VAP. Reliance upon these indicators in isolation may result in misdiagnosis and potentially unnecessary antimicrobial use.

Update of the treatment of nosocomial pneumonia in the ICU

“…Respiratory infections are the most prevalent nosocomial infection observed in ICUs [10]. In a broad global multicentre study, half the patients presented an infection at the time of the observation, 65% of respiratory origin [11] and HAP and VAP accounted for 22% of all hospital infections in a prevalence study performed in 183 US hospitals [12].…”

Pulmonary infections complicating ARDS

“…The diagnosis of lung infections in patients with ARDS is challenging [45]. The diagnosis of pneumonia, the dominant respiratory infection of concern in ARDS, is ultimately a histopathological diagnosis which requires the presence of airspace inflammation and an infecting organism.…”

“…The clinical features of systemic inflammation and localizing chest signs such as crepitations and bronchial breathing are non-specific and insensitive. While radiological evidence of airspace infiltration is useful, the gold standard of computed tomography is not practical for most patients, leading practitioners to rely on plain radiographs and ultrasound, and even computed tomography cannot always reliably distinguish between infective and non-infective causes of airspace infiltration [5,45]. Use of clinical and radiographic criteria alone are likely to significantly overestimate the rate of pneumonia and lead to excessive, potentially harmful, use of antibiotics [28].…”

A way towards ventilator-associated lower respiratory tract infection research

“…Intensive Care Medicine evaluating the diagnostic performance of ventilator-associated pneumonia (VAP) of physical examination findings (fever, purulent secretions), chest radiography, endotracheal aspirate cultures, bronchoscopic cultures, and Clinical Pulmonary Infection Score (CPIS) in comparison with either histopathology of lung tissue, or quantitative BAL cultures as reference standards [1]. Despite the findings of poor accuracy for diagnosis of VAP of individual clinical indicators, we believe that there are several shortcomings that were not fully discussed.…”