Expected and observed mortality in critically ill patients receiving initial antibiotic therapy

Area of Science:

• Critical Care Medicine
• Infectious Diseases
• Clinical Pharmacology

Background:

• Initial antibiotic therapy (IAT) is crucial for critically ill patients.
• Predictors of mortality in this population require further investigation.
• Understanding IAT effectiveness is key to improving patient outcomes.

Purpose of the Study:

• To identify predictors of mortality in critically ill patients receiving IAT within 48 hours of admission.
• To evaluate the accuracy of the SAPSII-expanded score in predicting mortality for these patients.
• To assess the impact of IAT response on patient outcomes.

Main Methods:

• Retrospective analysis of 631 critically ill patients admitted to an intermediate care unit.
• IAT initiated in 227 patients; data included laboratory markers, interventions, medications, SIRS/sepsis criteria, and mortality.
• IAT failure defined as increased C-reactive protein or leukocyte count on day 3.

Main Results:

• Patients receiving IAT had higher observed mortality (16.7%) versus expected mortality (19.2%) and controls (3.7%).
• Sepsis severity criteria did not accurately predict expected mortality, but significantly correlated with observed mortality.
• Failure to respond to IAT was associated with significantly higher observed mortality (26.3%) compared to responders (11.9%).

Conclusions:

• Critically ill patients receiving IAT exhibit a high morbidity burden and higher observed than expected mortality.
• The SAPSII-expanded score may not precisely estimate in-hospital mortality risk in IAT patients.
• IAT response is a critical factor influencing mortality; further research on central venous lines and guideline adherence is warranted.