Femoral Lines and Venous Thrombosis
Femoral Lines and Venous Thrombosis
Abstract & Commentary
This study was performed to determine the incidence of deep venous thrombosis (DVT) associated with the use of femoral venous catheters. Joynt and colleagues at the Chinese University of Hong Kong conducted a prospective, controlled, observational cohort study of all patients in their medical-surgical intensive care unit (ICU) who had femoral lines inserted during a 26-month period. Patients with previous DVT, hypercoagulable state, pelvic or abdominal trauma, prior femoral vein catheterization, or lower extremity ischemia were excluded, as were those who survived less than 24 hours after catheter insertion. All patients were studied with compression and duplex Doppler ultrasound of both femoral veins, before catheter insertion, then daily until catheter removal, and then one and seven days following removal. Routine DVT prophylaxis was not used.
A total of 124 patients qualified for the study, had femoral lines inserted, and had complete data. The right femoral vein was used in 105 patients and the left in 19. The mean age of the patients was 53 years and 41% of them were women. Approximately half had medical diagnoses; 25% were general surgery patients, 13% neurosurgery patients, and 8% trauma patients. Twelve percent of the cohort had known malignancy. The median APACHE II score for the group was 21 (range, 9-38).
Fourteen of the 124 patients (11.3%) developed DVT; this was in the leg with the femoral line in 12 (9.6%; relative risk 6.0, 95% CI 1.5-23.5; P = 0.011). There was no difference in DVT incidence between right and left legs, and neither the size nor the length of the catheter was related to incidence. Leg swelling was not appreciated more often in patients with DVT, and no patient in the study had clinically suspected pulmonary thromboembolism. Most of the catheters were heparin-bonded, but the incidence of DVT was not discernibly different with non-heparin-bonded catheters. The number of insertion attempts, inadvertent arterial punctures, whether a hematoma developed, the number of days the line was in place, and catheter colonization at removal were not related to the occurrence of DVT.
Joynt et al conclude that although the femoral route is convenient and has potential advantages for intravenous access and monitoring, the incidence of DVT is increased by the use of this route. (Joynt GM, et al. Chest 2000;117:178-183.)
COMMENT BY DAVID J. PIERSON, MD, FACP, FCCP
The most commonly used sites for venous access in critically ill patients are the subclavian and internal jugular veins. Use of these sites has complications, including pneumothorax with the subclavian route (reported in 1-5% of patients) and arterial puncture when the internal jugular is used (0.1-4%) (Agee KR, Balk RA. Crit Care Clin 1992;8:677-686). The femoral site has the advantages of no risk for pneumothorax, the ability to directly tamponade bleeding, and relatively straightforward anatomy, which decreases the risk for nerve damage and other complications.
It is common knowledge in critical care practice that use of the femoral route for venous access increases the likelihood of catheter-related infections, since the inguinal area is harder to keep clean than the upper thorax and neck. However, there is a paucity of actual data on this, and no randomized studies of infection risk at different venous sites have been published. One study of radial vs. femoral arterial catheterization found no differences in the incidence of infectious complications (Russell JA, et al. Crit Care Med 1983;11:936-939).
Joynt et al excluded patients with several conditions that would be expected to increase the likelihood of DVT. Still, about one in 10 patients who had a femoral line developed a DVT on the side with the catheter. These results raise several questions: How many, if any, of the observed DVTs were clinically important? Clearly, documented development of a DVT in a patient who did not have one before catheterization is an important potential problem. What is the incidence of DVT with other central line sites when studied with the same methods? Most likely, it is lower. Would the use of DVT prophylaxis have decreased the incidence? Probably. Still, the main observation of this study remains, and clinicians need to realize that the potential advantages of the femoral site for vascular access are accompanied by real disadvantages.
Compared with subclavian and internal jugular locations, the use of the femoral site for venous access has been proven to result in:
a. more line-associated infections.
b. an increased incidence of pneumothorax.
c. deep venous thrombosis in 10% of patients.
d. pulmonary embolism in 4% of patients.
e. None of the above
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