The relationship between volume status, hydration, and radiographic findings in the diagnosis of community-acquired pneumonia

. BACKGROUND Many clinicians believe the radiographic expression of communi ty-acquired pneumonia (CAP) is affected by the fluid volume status of the p atient. However, there are very few data to support or refute this concept. with this study we began to examine the relationship between admission flu id volume status and the radiographic expression of CAP. . METHODS Using a retrospective chart review, we examined 376 consecutive i npatient encounters with the diagnosis of pneumonia at discharge from a com munity teaching hospital. Patients were evaluated by age, sex, admission se rum sodium, blued urea nitrogen (BUN) level, creatinine, and fluid administ ered in the first 48 hours of treatment. We classified these patients as ei ther showing radiographic progression (P) or no radiographic progression (N P) by comparison of admission and follow-up radiographs. . RESULTS A total of 125 patient encounters satisfied inclusion criteria fu r the study. Using the Student t test we noted a statistically significant difference between the P and NP groups for BUN level (P=.02), volume of flu id administered during the first 48 hours (P=.04), and marginally for age ( P=.05). The P group had higher BUN levels (mean=34 vs 24), more 48-hour flu id intake (mean=5824 mt VS 4764 mL), and younger age (mean=59 years vs 66 y ears) than the NP group. Logistic regression poorly predicted which patient s would have worsening infiltrate on the second radiograph. . CONCLUSIONS Elevated admission BUN level and higher fluid volume administ ered in the first 48 hours of admission were associated with worsening radi ographic findings of pneumonia after hydration. Prospective studies are nee ded for confirmation of our results.