Comment on: Safe administration of vancomycin through a novel midline catheter: a randomized, prospective clinical trial

Dear Editor,

We recently read the article ‘Safe administration of vancomycin through a novel midline catheter: a randomized, prospective clinical trial’ by Caparas and Hu (1), which raised a number of concerns in this limited-sized patient sample study (n = 54), which we would like to address.

The authors did not consider ‘leak’ from the insertion site as potential thrombosis development, which is an early precursor of thrombus formation and compromised venous outflow, which has been clearly documented in literature over the last decade. It could also be due to advanced fibrin sheath development around the catheter body and lumen tip, allowing retrograde flow of an infused solution (irritant or not). The above clinical situations can be caused by both chemical (medication) and mechanical (physical) processes occurring within the vessel.

The paper stated if vancomycin therapy was extended beyond 5 days, physicians were advised to administer subsequent doses via a peripherally inserted central catheter (PICC) – so patients were subjected to a secondary device insertion and these numbers were not documented.

If blood return could not be demonstrated, the line was assessed with ultrasound to determine its position (which only described intraluminal position) – a catheter position change would be unlikely (unless withdrawn); however, ultrasound assessment was not mentioned or performed to observe/assess for potential thrombus development.

Assessment of the device and site was performed daily; however, it is documented that some patients also received a twice-daily dose of vancomycin, but there was failure to mention if the device or site was assessed during the second administration of the drug.

Three (10.0%) Grade 1 infiltrations (INS Infiltration Scale) occurred in the midline group. Twenty-nine percent (29%) of midline patients received intravenous vancomycin for greater than 5 days – how many of these patients had a device changed to a PICC (as recommendation in the paper) – this was also not addressed.

The reported thrombosis and phlebitis rates were zero (0) in both groups; however, it did not describe which phlebitis tool was used for assessment. The article by Ray-Barruel and colleagues (2), found that there are dozens of phlebitis assessment scales in use, but none have been thoroughly validated for use in the clinical setting and that there are broad disparities in measuring and reporting phlebitis, which have led to enormous variations in reported phlebitis prevalence rates.

The lack of addition of Alteplase™ (Genentech, USA) costs into the PICC group skews the economical comparison between the midline and PICC group. It was not addressed if Alteplase™ was used in the midline patient population to restore patency of the device. Although the authors showed a significant cost difference between the two groups (~US$90), it highlights vastly different types of devices in regard to overall costs and the insertion-related expenses. However, if the patient required an extension of therapy beyond the 5-day limit, then costs dramatically increased. If a PICC was initially placed for therapy, and was functional for the duration of infusion, then costs would be more accurate.

Two of the three infiltrations clearly occurred days after vancomycin administration had ceased – this cannot be contributed directly to vancomycin as there are other possible reasons for infiltration – power injection or other vesicant/irritant medication administration could have been a possible cause. Central line-associated blood-stream infection (CLABSI) should not be combated with increased midline use, as this hides the real and underlying issues within an institution if there is a strong CLABSI-related problem.

This area of research does need further high level, stringent clinical investigation, which has recently been achieved successfully by Klungboonkrong and colleagues (unpublished data), whose large 2522 midline catheter study investigating deep vein thrombosis (DVT) related to vesicant or irritant medication use through a midline, showed that there was a 56% increase after each successive dose of vesicant or irritant medication when administered, with an increased risk of DVT by a factor of 3.5. The authors’ recommendations were to use a central venous catheter for vesicant or irritant medication administration. This in-press publication requires careful consideration for guideline developers, policy writers, educators and researchers focusing on recommendations for clinical practice changes, which can have significant effects on patient- and device-related outcomes.

• 1. Caparas JP Hu J-V Safe administration of vancomycin through a novel midline catheter: a randomized, prospective clinical trial. J Vasc Access 2014 15 4 251 256
• 2. Ray-Barruel G Polit DF Murfield JE Rickard CM Infusion phlebitis assessment measures: a systematic review. J Eval Clin Pract 2014 20 2 191 202