Central venous catheter tip position and malfunction in a paediatric oncology unit

When used wisely, central venous catheters are capable of providing vital circulatory access in any patient with a remarkably low risk of infection or major complication. Tunneled silicone catheters are the route of choice for long-term or outpatient use, particularly for oncology or TPN patients; insertion of such a catheter should occur early in the hospitalization of a newly diagnosed patient on chemotherapy. The greatest experience has accrued with the cuffed silicone catheters (for example, Broviac), but the totally implantable devices (for instance, Port-a-cath) may become the device of choice in pediatric outpatients. For infants, small, percutaneously inserted noncuffed silicone catheters appear to offer the greatest safety. Among acute care patients, percutaneous plastic central venous catheters fulfill a vital role but represent an important source of infection. Scrupulous technique, the minimizing of manipulation, and a readiness to replace the catheter at any suggestion of trouble are important to achieving the best results. Within a given design, it is generally best to use the smallest diameter catheter capable of performing the desired tasks. However, on the basis of currently available data, there need be no hesitation to use a multilumen catheter if the care of the patient demands multiple access ports. The various silicone catheters can usually be left in place while infection is treated, although fungal and certain other infections are more likely to require catheter removal. Percutaneous plastic catheters should be removed or changed over a wire if infection is suspected; if tip culture of the removed catheter is positive, and the catheter was replaced over a wire, then the replacement catheter should be promptly removed.

To identify significant predictors of device-related infections, we performed a prospective, nonrandomized analysis of our experience with vascular access devices over a 2-year period in a pediatric oncology population. Variables analyzed included: (1) age at placement, (2) sex, (3) underlying disease, (4) type of device used (catheter v port), and (5) total white blood cell count at placement. Quantitative microbiologic criteria were used for diagnosis of bacteremia while clinical and microbiologic criteria were used in diagnosis of tunnel/port/site infections. During the study period a total of 351 devices, comprising 78,159 days in situ, were placed and data for univariate and multivariate analysis were available on 271 (77%). The mean age at placement was 7.2 +/- 4.7 years for catheters and 9.5 +/- 4.8 years for implantable devices (P less than or equal to .01). Significant predictors of device-related infections in univariate analysis were type of device (P less than or equal to .0001) and age (P less than or equal to .002). External catheters and age less than or equal to 7 years were associated with increased risk of infection. Underlying disease had a marginal effect on the infection rate (P = .08). In multivariate analysis, device type (P less than or equal to .0001) and age (P less than or equal to .002) continued to affect infections, whereas underlying disease demonstrated only a borderline effect (P = .14). We conclude that device type and age significantly affect the rate of device-related infections. These data support increased use of implantable devices in pediatric oncology patients.

We assessed the efficacy of local fibrinolytic therapy in 35 axillary-subclavian vein thromboses (SVT) that occurred in cancer patients with percutaneous central venous catheters (CVC). These catheters were indwelling for a median of 1 month (range, one day to 10 months) before thrombosis developed. Urokinase was administered at a dose of 500 to 2,000 U/kg/h. Complete lysis occurred in 25 of 30 thrombi that were directly infused, after a median of four days. Complete lysis occurred in one of 12 thrombi that could not be directly infused with urokinase and in two of six with associated phlebitis. Eighty-one percent of the thrombi that were symptomatic for less than 1 week before treatment resolved, compared with 56% present for longer than 1 week. Sixteen patients who had complete (12) or partial (four) thrombolysis did not have their CVCs removed. All four patients with partial thrombolysis had recurrent thrombosis at a median of eight days (range, one to 90). Only two patients who had complete thrombolysis had recurrent thrombosis, at 8 and 16 months. Only minor hemorrhagic toxicity was seen.