The risk factors for hospital-acquired pneumonia in the Intensive Care Unit

Patients in the intensive care units (ICU) are exposed to many factors that may cause hospital acquired pneumonia (HAP), a particular type of which is ventilator-associated pneumonia (VAP). The specific risk factors for developing VAP affect patients already on the day of their admission to a unit and are associated with their underlying diseases and invasive medical procedures, which they undergo. The aim of this study was to evaluate the risk factors for VAP associated with a patient and the used invasive treatment.

1227 patients were subject to the retrospective analysis. These patients were hospitalized between 2010 and 2014 in Intensive Care Unit (ICU) in the St. Luke District Hospital in Tarnów. Data about procedures used in ICU were obtained from the electronic hospital registration system and the decursus from each day when a patient stayed in the hospital, while information about hospital infections was obtained from the periodic department reports prepared by the Infection Control Team. In the diagnosis of VAP infections the definitions of nosocomial infections issued by CDC (Centers for Disease Control and Prevention) and ECDC (European Center for Disease Prevention and Control) were used.

In the analyzed unit, 58 cases of VAP were detected in patents who underwent mechanical ventilation. Infections were more common among men (43 cases, that is 6%) than in women (15 cases, that is 3%). Mechanical ventilation longer than 20 days was a major determinant of VAP (p < 0.001). Patient's underlying diseases (which are the reason for patient's admission to a unit) had an impact on the incidence of VAP, and the most important of them are: multiple trauma (20 cases of VAP per 217 patients (9.2% incidence)), sepsis (3 cases of VAP per 31 patients (9.7% incidence)), central nervous system disease (10 cases of VAP per 124 patients (8.1% incidence)), endocrine system (1 case of VAP per 12 patients (8.3% incidence)), respiratory diseases (11 cases of VAP per 168 patients (6.5% incidence)). Invasive medical procedures performed in the patients' respiratory tract were significant risk factors (p < 0.001) for developing VAP: reintubation (R=0.271), tracheostomy (R=0.309) and bronchoscopy (R=0.316). In the period from 2010 to 2014 VAP incidence was 4.7% and incidence density per 1000 ventilation-days was 10.5 and the mortality rate with VAP was 32.8%. The most common etiological factors of VAP were Acinetobacter Baumannie (21 isolates, that is 36.4%), Pseudomonas aeruginosa (8 isolates, that is 13.8%), Escherichia coli (7 isolates, that is 12%).