Impact of immunosuppression on the incidence of ventilator-associated events: an observational study

Critically ill immunocompromised patients requiring mechanical ventilation (MV) may be particularly vulnerable to ventilator-associated events (VAE), yet the impact of baseline immunosuppression on VAE incidence remains unclear. We conducted a secondary analysis of a cohort of adults requiring MV for ≥4 days in two ICUs of a tertiary hospital in Moscow, Russia. Using competing-risk regression, we compared the 30-day incidence of VAE between immunocompromised and non-immunocompromised patients. We then evaluated the association between VAE and 30-day ICU mortality among immunocompromised patients using Cox regression. Of 269 patients, 122 (45.4%) had baseline immunosuppression. The incidence of any VAE was higher in immunocompromised patients, though the estimate was imprecise (adjusted subhazard ratio [aSHR] 1.64; 95% CI 0.82–3.30); for infection-related ventilator-associated complications (IVAC), the estimate suggested a more than twofold increased hazard, but with considerable uncertainty (aSHR 2.22; 95% CI 0.85–5.78). In patients with immunosuppression, IVAC were associated with increased mortality (adjusted hazard ratio 2.38; 95% CI 1.16–4.89). Despite a higher estimated incidence of VAE in immunocompromised patients, we could not establish a clear association between baseline immunosuppression and VAE risk. IVAC were associated with increased mortality in immunocompromised patients, although this finding should be considered exploratory.