Preventing Catheter-Related Infection with Tunneled Femoral Catheters
abstract & commentary
Source: Timsit JF, et al. Ann Intern Med 1999;130:729-735.
Use of the femoral vein for vascular access appears to carry a higher risk of catheter-associated infection than does use of subclavian or jugular sites. Because femoral catheterization is easier to perform and does not carry a risk of pneumothorax, it is, nonetheless, often used in critical care settings.
Timsit and colleagues performed a randomized, controlled trial of tunneled femoral catheters in critical care units in three hospitals in Paris. All patients were required to have a Simplified Acute Physiologic Score II (SAPS II) of 20 or greater. Patients undergoing catheter exchange by guidewire were excluded. All catheters were single- or double-lumen; patients requiring triple-lumen catheters were ineligible. Catheters were inserted by physicians using strict aseptic technique and could be used for administration of medication, blood products, or parenteral nutrition, but could not be used for blood sampling. Patients randomized to "tunnelization" had the catheter passed through a subcutaneous tunnel over the anterior thigh to a point at least 10 cm from venous entry. Control patients received catheters directly inserted into the vein. Catheters were cultured quantitatively on removal, with 103 CFU or more considered to represent colonization. The main end point was "probable system catheter-related sepsis," which included "catheter-related sepsis without bacteremia" and "catheter-related bloodstream infection." (See Table.) Outcomes were judged by a blinded clinical panel. Catheters were removed by predetermined criteria based on signs of infection, mechanical dysfunction, or termination of IV therapy.
| Table |
| Trial End Points___________________________________________________________________ |
| Catheter-related sepsis without bacteremia:
1. T > 38.5° C or T < -36.5° C 2. Catheter tip cultures with >/- 103 CFU/mL 3. Pus at insertion site or tunnel or resolution of clincial sepsis after catheter removal |
| Catheter-related bloodstream infection:
1. One or more positive peripheral cultures within 48 hours (2 required for coagulase-negative staphylococci) 2. Catheter tip cultures with >/- 103 CFU/mL or local purulence 3. Same organism isolated from blood and catheter/insertion site ____________________________________________________________________________________________ |
A total of 336 (168 in each catheter group) evaluable patients were entered. The rate of "probable systemic catheter-related sepsis" was significantly lower in the tunneled catheter group (0.36/100 catheter days vs 1.1/100 catheter days; RR 0.25, 95%; CI 0.09-0.72). Although there was a trend for a similar reduction in catheter-related bacteremias (RR = 0.28), the difference was not statistically significant. This was due to the low number of bacteremias (4 total). Tunneled catheters were significantly less likely to be colonized than were control catheters. The tunneled catheter group had a significantly higher rate of local hematoma (6%) than did control patients (2%) but there were no major adverse sequelae.
Comment by Robert Muder, MD
Femoral insertion of central venous catheters is technically easier and safer than insertion into the jugular or subclavian veins. Intensivists are understandably reluctant to insert a catheter into an upper body site in a hemodynamically unstable patient who is receiving mechanical ventilation. Pneumothorax in such a patient could be disastrous; furthermore, hemorrhage at these upper body sites cannot be controlled by direct compression. However, safety and ease of insertion come at a price. In a number of studies, femoral catheters have had a higher rate of colonization and infection than those inserted in upper body sites.1-4
This study indicates that tunneling of femoral catheters at the time of insertion results in fewer infections than does routine percutaneous insertion. One possible criticism of the study is that the main outcome measurement showing a significant reduction was "probable systemic catheter-related sepsis," an outcome that could have included patients with fever due to a non-catheter-related cause and coincidental colonization. However, this determination was made by a blinded clinical panel, and there was a parallel reduction (although statisically not significant) in catheter-related bacteremia that was more rigorously defined. Therefore, I believe Timsit et al’s conclusions to be valid.
However, I would point out several important caveats. The first is that the catheters in the study were inserted under rigorous sterile conditions; tunneling is likely to be much less effective if the catheter is contaminated at the time of insertion because of poor sterile technique. The second is that the catheters were limited to single- and double-lumen devices. Triple-lumen catheters were excluded, and use of the catheter ports for blood sampling was expressly forbidden. Frequent use of catheter ports for sampling could introduce bacteria into the catheter lumen; tunneling would not be expected to influence the luminal route of infection. Third, the risk of local hematoma was three-fold greater in patients receiving tunneled catheters. Although none of these hematomas resulted in major adverse sequelae, it is quite possible that the frequency and seriousness of adverse effects would be higher outside of a controlled clinical trial. Finally, until a future study compares the infectious complications of tunneled femoral catheters with upper body site catheters, upper body sites are preferable for central venous access whenever they can be safely used.
References
1. Murr MM, et al. J Burn Care Rehabil 1991;12: 576-578.
2. Kemp L, et al. J Parenter Enteral Nutri 1994;18:71-74.
3. Collignon P, et al. Intensive Care Med 1988;14: 227-231.
4. Goetz AM, et al. Infect Control Hosp Epidemiol 1998; 19:842-845.
In the trial of tunneled femoral catheters:
a. the rate of "probable systemic catheter-related sepsis" was significantly lower in the tunneled catheter group.
b. all catheters were single- or double-lumen.
c. the risk of local hematoma was threefold greater in patients receiving tunneled catheters.
d. All of the above
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