Respiratory sepsis: a 12-year prospective observational study in critically ill patients

Pneumonia is the leading source of sepsis worldwide and remains associated with high morbidity and mortality. However, prospective long-term studies specifically describing the clinical characteristics, microbiology, and outcomes of patients with respiratory-source sepsis are scarce.

We conducted a 12-year prospective observational study (January 1, 2012-December 31, 2023) at the Department of Intensive Care Medicine, Donostia University Hospital, the only tertiary care center in Gipuzkoa, Spain. All adult ICU patients with sepsis or septic shock were included; this analysis focused on those with pneumonia as the infection source. Demographic and clinical features, microbiology, management, and prognostic factors for mortality were analyzed.

Our sepsis registry included 2116 ICU patients with sepsis or septic shock; pneumonia was identified as the infectious source in 590 cases (27.9 %), of which 434 (73.6 %) were community-acquired (CAP) and 156 (26.4 %) hospital-acquired (HAP), including 19 ventilator-associated pneumonia (VAP). Compared with CAP, HAP patients had higher APACHE II and SOFA scores, more frequent hemodynamic instability and thrombocytopenia, and greater need for vasoactive support, mechanical ventilation (MV), and renal replacement therapy (RRT). No significant differences were observed in sex, age, or admission levels of procalcitonin and lactate. Streptococcus pneumoniae predominated in CAP, whereas Escherichia coli and Pseudomonas aeruginosa were most common in HAP. ICU mortality was 24.7 % and overall hospital mortality 33.7 %, both higher in HAP. Multivariate analysis identified nosocomial origin as the strongest independent predictor of mortality, along with thrombocytopenia, hypoglycemia, need for MV and RRT, higher APACHE II, and lactate at admission.

Within our prospective sepsis registry, pneumonia was the most frequent infectious source. Nosocomial pneumonia, although less common than CAP, was associated with greater severity and emerged as the main independent predictor of mortality.