A cross-sectional study was conducted at Srinagarind Hospital, Faculty of Medicine, Khon Kaen University which is a 1466-bed tertiary care center in Northeast Thailand. The study was approved by the Human Research Ethics Committee, Khon Kaen University (approval number HE611281). All VAP patients recorded by the infectious control (IC) unit from January 1, 2015, to December 31, 2017, were enrolled.
VAP was diagnosed by the following criteria: 1) a pulmonary infection occurring 48 hours after mechanical ventilation 2) new pulmonary infiltration on chest radiograph 3) at least two of the three following characteristics: temperatures > 38.3 °C or < 36.5 °C, purulent tracheal secretions, and leukocytosis (white blood cell > 12,000 cells/mm3) or leukopenia (white blood cell < 4,000 cells/mm3) [4, 24]. The exclusion criteria were as following: 1) patients who had previous abnormal chest imaging including pulmonary edema, adult respiratory distress syndrome, pulmonary embolism, alveolar hemorrhage, pulmonary tuberculosis, and recent pneumonia 2) Immunocompromised patients who received any immunosuppressive agents, chemotherapy, or prednisolone equivalence ≥ 15 mg/day
The medical records of demographic data, hospital department, laboratory results, chest radiological findings, microbiological profiles, tracheostomy tube placement, hospital length of stay (LOS), intensive care unit (ICU) LOS, mechanical ventilator (MV) days and hospital mortality were reviewed.
Definition and outcome
EOVAP defined as VAP developed before 5 calendar days of hospitalization while LOVAP was VAP occurred at least 5 calendar days of hospitalization. Multi-drug resistant (MDR) bacteria were defined as organisms that resisted al least 3 classes of antibiotics. MDR pathogens included extended-spectrum beta-lactamase-producing (ESBL) bacteria, carbapenem-resistant enterobacteriaceae (CRE), MRSA, and other MDR bacteria that were reported from the microbiological laboratory. The causative organisms were defined as one or more of the following: 1) an isolated organism from hemoculture 2) an isolated organism from pleural effusion 3) an isolated numerous growth organism on a semiquantitative method or isolated organism on the quantitative method i.e. endotracheal aspirate > 105 colony forming unit (CFU)/ml, bronchoalveolar lavage > 104CFU/ml or protected specimen brush ≥ 103 CFU/ml. Hospital mortality was death occurring during the same admission of VAP diagnosis.
The primary oucome was to compare the MDR pathogen between EOVAP and LOVAP. The secondary outcome was to compare causative pathogens, hospital length of stay (LOS), ICU LOS, mechanical ventilator (MV) days, and hospital mortality between EOVAP and LOVAP.Factors associated hospital mortality of VAP were identified .
The categorical data were shown as numbers and percentages. The normal distributed continuous data were presented as mean and standard deviation (SD) while the non-normal distributed data were presented as the median and interquartile range (IQR). A comparison of category data used the Chi-square test and Fisher’s exact test depending on data. The nonparametric data used the Mann-Whitney U test for comparison. The factors associated with hospital mortality in VAP subjects were evaluated by univariate logistic regression analysis. The stepwise backward multiple logistic regression analysis of factors with a p-value < 0.2 on univariate analysis or factors with previous reports of clinical significance was performed. Crude odds ratio (cOR) and adjusted odds ratio (aOR) with their 95% confidence intervals (95% CI) were demonstrated. A p-value of less than 0.05 was considered statistically significant The statistical analysis was performed by Stata version 10.1(StataCorp, Texas, USA).