There is no clear consensus on the use of pneumonia severity index (PSI) developed for community-acquired pneumonia in hospital-acquired pneumonia cases. In another aspect, PSI is a relatively difficult scoring system that includes many parameters. This study evaluated whether lactate clearance could be used as a mortality marker instead of PSI in hospital-acquired pneumonia. As a result, lactate clearance was lower in the mortal group and when the diagnostic statistics were evaluated, it was seen that the sensitivity and specificity rates were significantly higher. In conclusion, lactate clearance has been evaluated as a strong predictor of mortality in hospital-acquired pneumonia.

Inclusion Criteria:

• 18 and over age, hospital-acquired pneumonia, emergency department admissions

Exclusion Criteria:

• Patients who are pregnant or lactating, under 18 years of age, in the healthcare-associated pneumonia group, had mechanical ventilation at the last hospitalization, whose lactate level could not be studied for any reason at admission and 6th hour, had missing data used in pneumonia severity index calculation and/or who did not accept to participate in the study

Patients at the age of 18 and over with at least 48 hours of hospitalization within the specified study date range, who were discharged from the hospital within the last 14 days related to this hospitalization, who were re-admitted to the adult emergency department and were diagnosed with pneumonia were included in the study.