Enteral nutrition volume is not correlated with lower respiratory tract infection in patients on mechanical ventilation

Objective: To evaluate the effect of enteral nutrition volume, gastrointestinal function and the type of acid suppressive drug upon the incidence of lower respiratory tract infections in critically ill patients on mechanical ventilation (MV).

Design: A retrospective secondary analysis was carried out.

Setting: The Intensive Care Unit of a University Hospital.

Patients or participants: Patients≥18-years-old expected to need MV for more than four days, and receiving enteral nutrition by nasogastric tube within 24h of starting MV.

Interventions: We correlated enteral nutrition volume administered during the first 10 days, gastrointestinal function and the type of acid suppressive therapy with the episodes of lower respiratory tract infection up until day 28. Cox proportional hazards ratios in univariate and adjusted multivariate models were used. Statistical significance was considered for p<0.05.

Main variables of interest: Lower respiratory tract infection episodes.

Results: Sixty-six out of 185 patients (35.7%) had infection; 27 patients had ventilator-associated pneumonia; and 39 presented ventilator-associated tracheobronchitis. Uninfected and infected groups were similar in terms of enteral nutrition volume (54±12 and 54±9mL/h; p=0.94) and caloric intake (19.4±4.9 and 19.6±5.2kcal/kg/d; p=0.81). The Cox proportional hazards model showed neurological indication of MV to be the only independent variable related to infection (p=0.001). Enteral nutrition volume, the type of acid suppressive therapy, and the use of prokinetic agents were not significantly correlated to infection.

Conclusions: Enteral nutrition volume and caloric intake, gastrointestinal dysfunction and the type of acid suppressive therapy used were not associated to lower respiratory tract infection in patients on MV.