Time to positivity in blood cultures of adults with Streptococcus pneumoniae bacteremia

BACKGROUND: previous studies have established that bacterial blood concentration is related with clinical outcome. Time to positivity of blood cultures (TTP) has relationship with bacterial blood concentration and could be related with prognosis. As there is scarce information about the usefulness of TTP, we study the relationship of TTP with clinical parameters in patients with Streptococcus pneumoniae bacteremia. METHODS: TTP of all cases of Streptococcus pneumoniae bacteremia, detected between January 1995 and December 2004 using the BacT/Alert automated blood culture system in a teaching community hospital was analyzed. When multiple cultures were positive only the shortest TTP was selected for the analysis. RESULTS: in the study period 105 patients with Streptococcus pneumoniae bacteremia were detected. Median TTP was 14.1 hours (range 1.2 h to 127 h). Immunosuppressed patients (n = 5), patients with confusion (n = 19), severe sepsis or shock at the time of blood culture extraction (n = 12), those with a diagnosis of meningitis (n = 7) and those admitted to the ICU (n = 14) had lower TTP. Patients with TTP in the first quartile were more frequently hospitalized, admitted to the ICU, had meningitis, a non-pneumonic origin of the bacteremia, and a higher number of positive blood cultures than patients with TTP in the fourth quartile. None of the patients with TTP in the 90(th )decile had any of these factors associated with shorter TTP, and eight out of ten patients with TTP in the 10(th )decile had at least one of these factors. The number of positive blood cultures had an inverse correlation with TTP, suggesting a relationship of TTP with bacterial blood concentration. CONCLUSION: Our data support the relationship of TTP with several clinical parameters in patients with Streptococcus pneumoniae bacteremia, and its potential usefulness as a surrogate marker of outcome

Anticipated resource utilization for injury versus non-injury pediatric visits to emergency departments

BACKGROUND: Childhood injuries are increasingly treated in emergency departments (EDs) but the relationship between injury severity and ED resource utilization has not been evaluated. The objective of this study was to compare resource utilization for pediatric injury-related ED visits across injury-severity levels and with non-injury visits, using standardized, validated scales. METHODS: A retrospective analysis of 2004-2008 ED visits from the Pediatric Emergency Care Applied Research Network Core Data Project. Maximum Abbreviated Injury Scale severity (MAIS) and Severity Classification System (SCS) scores were calculated and compared. MAIS and SCS are ordinal scales from 1 (minor injury) to 6, and 1 (low anticipated resource utilization) to 5, respectively. ED length of stay (LOS) and admission percentages were calculated as comparative proxy measures of resource utilization. RESULTS: There were 763,733 injury visits and 2,328,916 non-injury visits, most with SCS of 2 or 3. Of the injured patients, 59.2 % had an MAIS of 1. ED LOS and admission percentage increased with increasing MAIS from 1-5. LOS and admission percentage increased with increasing SCS in both samples. Median LOS was shorter for injured versus non-injured patients with SCS 3-5. Non-injured patients with SCS 2-5 were more likely admitted than injured patients. Most injured patients had an SCS 3 with an MAIS 1-2, or an SCS 2 with an MAIS 1, with no correlation between the two scales. CONCLUSION: While admission rates and LOS increase with increasing AIS and SCS severity, these two classification schemas do not reliably correlate. Similarly, ED visit metrics differ between injured and non-injured patients in similar SCS categories. Although AIS and SCS both have value, these differences should be considered when using these schemas in research and quality improvement