|Topic:||30. Sepsis / Adult / Clinical Studies / Critical Care (CC)|
|Authors:||N. Maniar, R. Cavallazzi; Louisville, KY/US|
The neutrophil-to-lymphocyte ratio, increased red cell distribution width, and band count have been associated with bacteremia and increased mortality. However, there is a scarcity of studies on patients in the Intensive Care Unit. We decided to conduct a study evaluating the accuracy of these parameters for the diagnosis of bacteremia in ICU patients.
This was a retrospective case-control study. Patients admitted to the ICU for any diagnosis between 2011 and 2015 were selected. Patients with a positive blood culture were the cases and those with a negative blood culture were the controls in a 1:2 ratio for a total of 749 patients. Complete blood counts drawn on the same day as blood cultures were analyzed. We calculated the accuracy of neutrophil-to-lymphocyte ratio, band count and increased red cell distribution width for the diagnosis of bacteremia in critically ill patients.
We included 749 patients. Their mean age was 55 years-old (SD: 16.5) and 64.2% were male. A band count greater than 10% had sensitivity of 16.3 (95% CI: 12 - 21.5), specificity of 95.6 (95% CI: 93.4 - 97.2), positive likelihood ratio of 3.7 (95% CI: 2.25 - 6.07), and negative likelihood ratio of 0.87 (95% CI: 0.82 - 0.93). A neutrophil-to-lymphocyte ratio greater than 7 had sensitivity of 62.9 (95% CI: 56.6 - 68.9), specificity of 49.4 (95% CI: 44.9 - 53.9), positive likelihood ratio of 1.24 (95%CI: 1.09 - 1.41), and negative likelihood ratio of 0.75 (95% CI: 0.62 - .90). Red cell distribution width greater than 14.6 had sensitivity of 64.1 (95% CI: 57.9 - 70.1), specificity of 51.4 (95% CI: 46.9 - 55.9), positive likelihood ratio of 1.32 (95% CI: 1.16 - 1.5), and negative likelihood ratio of 0.7 (95% CI: 0.58 - 0.84).
None of these parameters provide high accuracy for the diagnosis of bacteremia in the ICU. They may be useful if integrated into pre-test probability of bacteremia along with other clinical characteristics. However, these parameters do not substantially change the post-test probability of bacteremia.