Vitamin K deficiency and D-dimer levels in the intensive care unit: a prospective cohort study.

Patients in the intensive care unit (ICU) are at risk for the development of vitamin K deficiency. We sought to determine the frequency of this deficiency by performing a prospective cohort study in which patients were screened for vitamin K deficiency on ICU admission and every other day thereafter. Vitamin K deficiency was diagnosed by a functional coagulation factor II to Echis factor II ratio < 0.70. Activity of the coagulation cascade was measured by D-dimer. In total, 40 patients were enrolled into the study. Seven of the patients had ratios < 0.70 on the day of admission to the ICU, and three patients developed ratios < 0.70. Thus, 10 of 40 patients (25%; 95% confidence interval, 12-38%) had vitamin K deficiency. Two patients developed coagulopathy, as indicated by an International Normalized Ratio of more than 1.4. D-dimer levels were elevated in 86 of 111 samples. We conclude that vitamin K deficiency is common among critically ill patients, particularly on admission to the ICU. Our findings suggest that additional clinical research is warranted to determine whether vitamin K supplementation on admission to the ICU reduces the risk of ICU-acquired vitamin K deficiency and its attendant complications over the course of the ICU stay.