ObjectivesTo determine the rate of lower extremity deep vein thrombosis after the use of femoral catheters in intensive care unit (ICU) comatose or sedated adults. Results were then compared with results of patients undergoing superior vena cava catheterization.DesignProspective, randomized, controlled, unblinded study.SettingA mixed medical/surgical ICU in a university hospital.PatientsSixty-one comatose or sedated patients admitted to the ICU who underwent central venous catheterization.InterventionsPatients were monitored for signs of thrombotic complications. On catheter removal, a lower-extremity bilateral phlebographic examination was performed in each patient.Measurements and Main ResultsAfter randomization, 31 patients underwent femoral vein catheterization and 30 patients underwent superior vena cava catheterization, either by axillary (21 patients) or internal jugular vein (10 patients) cannulation. Single lumen polyurethane catheters were inserted for a mean duration of 7.1 +/- 4.6 (SD) days in the femoral vein group and 9.9 +/- 5.5 days in the superior vena cava group (p=NS). No patient had clinical signs of leg venous thrombosis or pulmonary embolism during the study period. In each patient, lower extremity bilateral phlebography was performed at the time of catheter removal. Leg phlebographies were normal in 18 (60%) patients in the femoral vein group and 26 (84%) patients in the superior vena cava group. Fibrin sleeves which developed around the femoral catheters were seen in seven (23.3%) patients in the femoral vein group and in no patients in the superior vena cava cannulation group. Three patients had femoral vein thrombosis, two (6.6%) patients in the femoral vein group (two nonobstructive thromboses, adherent to the common femoral vein wall) and one (3.0%) patient in the superior vena cava group (nonobstructive thrombosis which developed in the superficial femoral vein) (p = NS). Lower deep extremities thrombosis developed in five (16.7%) patients in the femoral vein group and in five (16%) patients in the superior vena cava group (p=NS).ConclusionsFemoral vein catheterization with a polyurethane catheter is associated with a lower rate of extremity deep vein thrombosis which is similar to the rate observed after superior vena cannulation in comatose or sedated patients. Femoral vein thrombosis was observed at a rate of 6.6% after femoral vein cannulation and a rate of 3% after superior vena cava cannulation. Given the acceptable rate of this clinically important complication, femoral vein cannulation offers an attractive alternative to insertion via the vena cava in the critically ill. (Crit Care Med 1997; 25:1982-1985)