IntroductionIntravascular cooling and warming catheters are among a range of proliferating technologies used for temperature control. Complications related to the use of these devices are few, and no definitive evidence has been presented thus far to indicate any differences in complication rates between these balloon catheters and other central vein catheters. We report two cases of cooling and warming catheter-related venous thrombosis. They are the both first ones report of this kind in the literature.Case presentationThe first case was a 17-year-old man admitted with severe head trauma. On day 6, he presented with severe intracranial hypertension, requiring increased medical treatment: mannitol osmotherapy, barbiturate-induced coma, and mild therapeutic hypothermia. A double-lumen Alsius CoolLine catheter was placed in the inferior veina cava via the left femoral vein and active cooling was begun. On day 10, physical examination of the left inguinal area and echo-doppler revealed catheter-related thrombophlebitis with left iliocaval vein occlusion. The second case was a 42-year-old man admitted with a severe burn. On day 2, the patient was taken to the operating room for the first staged excision of his burn wounds. A triple lumen Alsius Icy catheter was placed in the inferior vena cava via the right femoral vein and active core warming of the patient was begun. From day 2 to day 7, active core warming of the patient was maintained. On day 7, he presented with a septic thrombophlebitis. Echo-doppler revealed a 4-cm-long thrombus at the femoral catheter site with complete blood flow obstruction and blood cultures and catheter tip were positive for methicillin-resistant Staphylococcus aureus.ConclusionAlthough generally considered safe, cooling and warming catheters can be associated with mechanical complications such as catheter-related venous thrombosis. Intensivists who use these devices should be aware of this possible complication. Finally, as with any other invasive catheter, to reduce the risk of complications, the catheter should be removed promptly when no longer needed.