Abdominal infection plays a role in the incidence of ventilator-associated pneumonia

Introduction

Despite many therapeutic interventions, ventilator-acquired pneumonias (VAP) are frequent in the ICU and are associated with major morbidity and mortality. Sepsis causes a time-dependent modification of the inflammatory response. This reprogramming could promote the occurrence of a secondary infection and worsen the prognosis. In animals, peritonitis is associated with an alteration of pulmonary immunity and an increasing mortality from secondary pneumonia.

Methods

To investigate, in humans, the potential involvement of previous intra-abdominal infection (IIA) in preventing or promoting VAP, we realized a prospective observational study using data from a multicenter database (OUTCOMEREA), including all patients admitted to the ICU for severe sepsis or septic shock who required mechanical ventilation for at least 72 hours.

Results

In total, 2,623 patients were included, of which 290 had an IIA. A total of 862 patients (33%) developed a VAP, 56 (19%) in the IIA group and 806 (34%) in the non-IIA group (P < 0.01). VAP, after sepsis, occurred less frequently and later in patients with IIA. The occurrence of IIA, in comparison with another sepsis, is a protective factor against VAP (HR = 0.643 (0.478 to 0.863), P = 0.003). There is, however, no significant difference between the groups in terms of ICU mortality (28% vs. 32%, P = 0.16). See Figures 1 and 2.

Figure 1

Cumulative incidence of VAP.

Figure 2

Cumulative occurrence of death.

Conclusion

In this study, the presence of an abdominal sepsis, in a context of severe sepsis or septic shock, was associated with a lower incidence of later VAP. These results have to be confirmed in other studies, especially prospective. They open interesting new research directions.