Circulating NT-proCNP predicts sepsis in multiple-traumatized patients without traumatic brain injury

Objectives: C-type natriuretic peptide (CNP), a member of the natriuretic peptide family, is produced in vascular endothelium. We assessed the accuracy of natriuretic (NT)-proCNP, the N-terminal fragment of the C-type natriuretic peptide precursor, in predicting development of sepsis in multiple-traumatized patients with/without traumatic brain injury verified by computed tomography. Design: Retrospective clinical study. Setting: Level II trauma center. Patients: Three patient groups were stratified according to computed tomography results: isolated traumatic brain injury (n = 20), multiple-traumatized with traumatic brain injury (n = 26) and multiple-traumatized without traumatic brain injury (n = 26). During 13 days after multiple trauma, 37 (51%) patients developed sepsis. Measurements and Main Results: Circulating plasma NT-proCNP levels were measured daily (days 0-13) in all patients. Without any retrospective stratification of trauma patients, plasma NT-proNCP levels did not differ in septic (n = 37) and nonseptic (n = 35) patients (p = .505). Between days 2 and 6 posttrauma, there was a significant (p = .002) increase of circulating NT-proCNP in multi pie-traumatized patients without traumatic brain injury who developed sepsis (n = 19) compared with nonseptic multiple-traumatized patients without traumatic brain injury. Conversely, in septic patients either with traumatic brain injury alone or with multiple trauma and traumatic brain injury, the NT-proCNP showed a trend toward lower levels than in nonseptic patients. Prediction of sepsis (receiver-operating characteristic test) from days 2 to 6 after multiple trauma by NT-proCNP in patients without traumatic brain injury was accurate with an area under the curve of 0.84 +/- 0.03. The optimal cutoff value of 2.3 pmol/L produced sensitivity of 84% to 96% and specificity of 61% to 91% from day 2 to 6 after trauma. Conclusions: Our data showed that the levels of circulating NT-proCNP between multiple-traumatized patients without traumatic brain injury who do and do not develop sepsis are distinctly different. Plasma NT-proCNP concentration can potentially serve as an accurate predictor of sepsis in this cohort of patients. (Crit Care Med 2010; 38:161-166)