[Comprehensive prevention and pathogenesis of ventilator-associated pneumonia in elderly patients: a prospective, randomized, case-control clinical trial].

OBJECTIVE: To assess the value of comprehensive prevention measures to ventilator-associated pneumonia (VAP) of patients more than 60 years old and to investigate the pathogenesis of VAP. METHODS: With a prospective, randomized, case-control design, patients more than 60 year of age with expected mechanical ventilation > 48 h were randomly assigned to a control group receiving a standard endotracheal tube or a comprehensive intervention group including semi-recumbent, mosapride citrate, and endotracheal tube for continuous subglottic secretions drainage. The duration of mechanical ventilation, length of ICU/hospital stay, the incidence, mortality, contributable mortality, relative risk as well as the bacterial concordance in gastric juice or lower respiratory tract between two groups were compared. The rates of methylene blue found in lower respiratory tract were also observed. RESULTS: Eighty-six cases were enrolled in this trial, including 41 in the intervention group and 45 in the control group. The duration of mechanical ventilation, length of ICU/hospital stay in the intervention group were all less than the control group. However, no significant difference existed in mortality and attributable mortality. Same types of bacterial pathogens were found between gastric juice and lower respiratory tract of the VAP patient. The RR of the incidence of VAP in two groups was 0.259 (95% CI 0.106 - 0.634). The rate of the same bacterial type or methylene blue detected in lower respiratory tract/oropharynx under microscope in the intervention group were lower than the control group (P < 0.05). CONCLUSIONS: The comprehensive prevention measures can reduce the incidences of VAP. The astro-pulmonary route is one of the pathogenesis of VAP.