The usually applied conversion technique from temporary to tunneled central venous catheters (CVCs) using the same venous insertion site requires a peel-away sheath.
We propose a conversion technique without peel-away sheath: a guide wire is advanced through the existing temporary CVC; then, a subcutaneous tunnel is created from the exit to the venotomy site (Figure 1). After removing the temporary CVC, the tunneled one is advanced along the guide wire (Figure 2). The study group included all patients requiring a catheter conversion from January 2012 to June 2014; the control group included incident patients who had received de novo placement of tunneled CVCs from January 2010 to December 2011. The main outcome measures were technical success and immediate complications.
Seventy-two tunnelled catheters, 40 with our conversion technique and 32 with the traditional technique were placed in 72 consecutive patients during the entire study period. The comparison between the two groups is shown in Table 1. The outcome variables are shown in Table 2. The technical success (catheter insertion without a peel-away sheath with a correct tip position) was obtained in 38 patients (95%) of the study group and in 24 (75%) of the historical control group (p= 0.019). Two cases in the study group required the peel-away sheath, and in one of them (in LJV) the catheter was dislodged. In historical control group, 6 catheters (4 inserted in LJV, 2 in RJV) were dislodged and two (1 in RJV and 1 in FV) had an incorrect tip position. Overall, there were 9 episodes of catheter malfunction that necessitated intervention but not catheter removal. In these cases, a standard angiography was used for all procedures of catheter recovery. Although the catheter dysfunction was lower in the conversion group (7.5% vs. 25%), the difference was not statistically significant (p=0.056). As far as the immediate surgical complications are concerned, one episode of bleeding occurred with the conversion technique (2.5%), whereas six episodes (one air embolism, one pneumothorax, four bleedings) (18.7%) occurred in the control group (p=0.039). Only one exit-site infection was recorded in the study group, but no CRB episode was reported in both groups during the mean follow-up period of 12 ± 3 days.
In conclusion, it is our strong belief that, due to the fact that complications of tunneled catheter placement are frequent, nephrologists should practice techniques that limit these risks. The conversion from temporary to tunneled CVC without a peel-away sheath is an effective and safe procedure, when catheters with comparable French are used. It may be advised as elective especially in the elderly patients who have exhausted all other possibilities of vascular access.