Protein C levels in critically ill ICU patients: differences seen between patients with and without sepsis

Abstract number: P0013

Gosselin R. C., Roach D. M., King J. H., Larkin E. C., Alberston T., Owings J. T.

UC Davis Medical Center, USA

Introduction  

It has been suggested that protein C (PC) levels can predict outcome in patients with sepsis. We sought to determine PC levels in critically ill ICU patients, with and without sepsis.

Methods  

Shed blood from ICU patients was collected, processed and the plasma frozen for batch analysis. PC, factor VIII, fibrinogen, d-dimer, and antithrombin levels were assayed on each sample. WBC count, absolute neutrophil count, INR, total bilirubin, BUN, postop days, service, heart rate (HR), respiration rate (RR), body temperature (To), number and type of organ failures (OF), known or suspected infection were obtained from chart review. Systemic inflammatory response syndrome (SIRS) criteria were defined two or more of the following: T_o: >38 °C or <36 °C; HR > 90 bpm; RR > 20 min^-1 or PaCO₂ < 32 Torr; WBC count > 12 000 or <4000 mm^-3, or >10% bands. The Prowess study identified septic patients as having SIRS with at least 1 OF, our institution identified septic patients as having SIRS with at least 2 OF. We correlated PC, antithrombin, factor VIII, d-dimer and fibrinogen to both definitions of sepsis using a multivariate logistic regression analysis.

Results  

A total of 111 patients enrolled, 53 males (47.8%), mean age 58.3 years (14–92). There were 54 medical (48.6%), 38 surgical (34.2%), and 19 trauma (17.1%) patients. SIRS with at least 1 OF: 40/111 (36.0%) septic, SIRS with at least 2 OF: 24/111 (21.6%) septic. There were known infections in 54 patients (48.6%) and 23 deaths (20.7%). The mean PC levels in patients without and with sepsis: for SIRS with at least 1 OF criteria: 0.71 IU mL^-1 vs. 0.53 IU mL^-1 (P = 0.003); for SIRS with at least 2 OF criteria: 0.68 IU mL^-1 vs. 0.50 IU mL^-1 (P = 0.007). Normal PC values in our laboratory are 0.70–1.40 IU mL^-1. No other laboratory parameter, age, or service demonstrated significant differences between the septic and nonseptic patients using either definition. Using death as outcome, using the SIRS with at least 1 OF criteria: 23/40 (57.5%) patients died, while using the SIRS with at least 2 OF criteria: 23/24 (95.5%) patients expired.

Conclusions  

Using SIRS with at least one organ failure as the criteria for sepsis, there was a significant difference in PC levels between ICU patients with and without sepsis. However, SIRS with multiple (at least 2) organ failure was associated with higher mortality, independent of protein C levels.