Evaluating the Risk of Developing Thrombocytopenia Within Five Days of Continuous Renal Replacement Therapy Initiation in Septic Patients.

Background: The differential diagnosis for thrombocytopenia in critical illness is often extensive. This study was performed to determine the incidence of thrombocytopenia in septic patients undergoing continuous renal replacement therapy (CRRT) versus those not undergoing CRRT.

Objective: The primary outcome of this study was to compare the development of thrombocytopenia, defined as a platelet count ≤ 100 × 10/mm, in septic patients within 5 days of time zero. Time zero was defined as the baseline platelet count upon hospital admission or CRRT initiation.

Methods: An IRB approved, retrospective cohort study was conducted evaluating thrombocytopenia development in critically ill, septic patients who were initiated on CRRT versus those whom were not. Baseline and clinical characteristics were displayed using descriptive statistics. The primary outcome was evaluated overall and in subgroups of CRRT using Chi-square tests.

Results: One hundred sixty patients, 80 per arm, were included in the study. Thrombocytopenia development within 5 days occurred more frequently in the renal replacement therapy (RRT) group compared to the control group (67.5% vs. 6.3%, p < 0.001). In the subgroup analysis of the RRT cohort, thrombocytopenia development within 5 days occurred more frequently in the continuous veno-venous hemofiltration (CVVH) group compared to the accelerated veno-venous hemofiltration (AVVH) group (76% vs. 53.3%, p = 0.049).

Conclusion: There is a high likelihood that septic patients initiated on CRRT will develop thrombocytopenia during their hospital stay. Patients receiving CVVH may develop thrombocytopenia more frequently than those receiving AVVH. Overall, CRRT should remain a differential diagnosis for thrombocytopenia development in this patient population.