Diagnosis of Acute Respiratory Distress Syndrome in Nosocomial Pneumonia

Abstract

Objective: to define the informative value of the parameters of gas exchange, lung volumetry, and central hemodynamics in the diagnosis of acute respiratory distress syndrome (ARDS) in nosocomial pneumonia (NP). Subjects and methods. The study included 38 patients with cancer and severe injury who were divided into 3 groups in accordance with the diagnostic criteria of ARDS and NP: 1) patients with ARDS + NP; 2) those with NP; 3) those with non-ARDS, non-PN. ARDS was diagnosed in 2 steps. At Step 1, the investigators took into account risk factors for ARDS and used the lung injury scale developed by J. Murray et al. and the ARDS diagnostic criteria defined by the American-European Consensus Conference on ARDS. At Step 2, after obtaining the data of lung volume-try (1—2 hours after Step 1), they assessed the compliance of the above criteria for ARDS with those developed by the V. A. Negovsky Research Institute of General Reanimatology, Russian Academy of Medical Sciences, and redistributed the patients between the groups. The stage of ARDS was determined in accordance with the classification of the above Institute. All the patients underwent a comprehensive examination the key element of which was to estimate gas exchange parameters and to monitor lung volumetry and central hemodynamics by the transpulmonary thermodilution methods, by using a Pulsion PiCCO Plus monitor (Pulsion Medical Systems, Germany). The findings were statistically analyzed using a Statistica 7.0 package (arithmetic mean, error of the mean, _ Student’s test, Newman-Keuls test, correlation analysis). The difference was considered to be significant if p-value was Results. The patients with ARDS + NP were observed to have a significantly lower oxygenation index (10 ml/kg) and Murray scale scores (>2) than those in patients with NP without ARDS. The reference values of the pulmonary vascular permeability index due to its inadequate informative value call for further investigation. The volumetric parameters of central hemodynamics are required to confirm the non-cardiogenic nature of pulmonary edema. Conclusion. Oxygenation index, ELWI, static lung compliance, and Murray scale scores are of informative value in the diagnosis of ARDS in NP. The use of the criteria developed by the V. A. Negovsky Research Institute of General Reanimatology allows the false-positive results of the diagnosis of ARDS in NP to be ruled out in 21.7% of cases. Only the integrated assessment of these parameters enables the diagnosis of ARDS in NP. Isolated analysis may lead to diagnostic errors. No increase in ELWI was found in NP without ARDS. Key words: acute respiratory distress syndrome, nosocomial pneumonia, diagnosis.