The prognostic value of global haemostatic tests in the intensive care unit setting

Global haemostatic tests are often abnormal in critically ill patients, secondary to activation or consumption of coagulation factors or inhibitors. Methods for analysing plasma levels of these factors are, however, not widely available, and the predictive value of global tests is not known. We examined the clinical applicability to predict the outcome of the global haemostatic tests used at most hospitals.

Blood was collected from patients within 6 h of admission to an intensive care unit (ICU) and tested regarding platelet count, International Normalized Ratio (INR), and activated partial thromboplastin time (APTT). Ninety-two patients with platelet counts <100 x 10(9) l(-1), INR > 1.36 and/or APTT >45 s were included in a study group, and an additional 92 patients with a comparable age and sex distribution, but not fulfilling these laboratory criteria, constituted a control group. The following data were recorded for each patient: number of days in the ICU and hospital; alive or deceased when released from the ICU and hospital; survival at 30 days and 180 days.

Survival upon discharge from the ICU and hospital was significantly reduced in the study group. This was especially pronounced in patients with medical disorders, whereas the survival rate was slightly higher in surgery patients. Expressing the survival predicting ability of the screening tests as odds ratios for all patients (study and control groups together) indicated that prolonged APTT in particular foretold a lower survival rate at studied time-points after admission to the ICU.

The global haemostatic tests INR and APTT can predict survival in critically ill patients, and prolonged APTT in particular seems to be associated with a negative prognosis.