Influence of different ventilator circuit change frequency on ventilator-associated pneumonia

Abstract

Objective To explore the appropriate frequency of ventilator tube replacement by researching the influence of different ventilator circuit change frequency on ventilator-associated pneumonia (VAP). Methods A prospective randomized sampling study was conducted. The patients undergoing invasive mechanical ventilation over or equal to 3 days admitted to emergency intensive care unit (EICU) of the First Affiliated Hospital of Kunming Medical University from December 2012 to December 2015 were enrolled. The patients were divided into 3, 7 and 10 days group according to the frequency of ventilator tube replacement. Bacteriology of ventilator tube and the incidence of VAP were compared among the groups. Results Ninety-eight patients were enrolled, mainly with the artificial airway of endotracheal intubation or tracheotomy, with 56 male and 42 female, aging 8 to 86 years with mean of (51.97±17.56) years. There were no statistical differences in gender, age, Glasgow coma scale (GCS) score, cough function and application of glucocorticoid, enteral nutrition, atomization and sedative therapy among three groups, indicating that the risk factors among three groups were consistent. The bacteria detection rates of extension tube, breathe out tube, breathe in tube, and hydrops collection cup were 36.7%, 36.7%, 33.3%, and 33.3% respectively in 3 days group, and they were 73.0%, 67.6%, 62.2%, and 62.2% in 7 days group respectively, and were all 90.3% in 10 days group. It was showed that the bacteria detection rate in different pipe parts was almost the same with the same change frequency, and the rate was higher with the longer usage of ventilator tube (χ2 values were 20.599, 19.879, 21.975, 21.975, all P = 0.000). The longer of the tube used time, the higher incidence of VAP. The incidence of VAP in 3, 7, 10 days groups were 26.7%, 59.5% and 77.4%, respectively, but there was statistically significant difference among all groups (χ2 = 30.486, P < 0.001). Based on the value of 3 days group, the incidence of VAP in the 7 days group was 15.950 folds of 3 days group, and the incidence of VAP in the 10 days group was 18.333 folds of the 3 days group (both P < 0.001). Conclusion This study suggests that the longer of pipeline using time, the more serious degree of bacterial contamination of pipeline, the higher incidence of VAP. Key words: Ventilator-associated pneumonia; Mechanical ventilation; Ventilator tube; Frequency of replacement