We read with interest the report by Mermel and colleagues [1] on safety issues associated with midline catheters. In fact, because of transient flushing associated with catheter use, we previously examined the ability of catheters to release histamine from basophils and reported that neither the Landmark catheter nor control catheters released histamine in a non-IgE-mediated reaction [2]. Because of the questions raised by Mermel and associates [1], we obtained from the manufacturer detailed medical histories of all patients in whom adverse events were reported with the Landmark catheter. More recent data show that a total of 726 000 catheters have been used and that only 173 adverse events occurred, resulting in an incidence of less than 1/4000. These 173 events can be classified as vasovagal reactions, transient pain, psychologically based (that is, hyperventilation), caused by preservative in the saline used for flushing or in heparin, secondary to disease, secondary to drugs being administered, or secondary to interactions of a drug with a specific disease. No deaths could be related to insertion, no miscarriages were noted, and most patients had clinically significant underlying disease. We noted 39 rashes; all appeared to have been caused by drug treatment or transient flushing. No rash persisted or evolved. One patient experienced an embolism but was known to have had underlying phlebitis. In fact, many patients who had an adverse event tolerated the Landmark catheter on subsequent use.

These event data are consistent with previous data of vasovagal reactions, transient rashes, and similar events found in various outpatient areas, including use of other catheters, colonoscopy, and outpatient surgery [3-5]. We also noted that of the 173 reported events, more than 150 resolved within 5 minutes without treatment, leaving 23 events in 726 000 catheterizations. All patients had severe underlying disease associated with multiple drug treatments. Use of the Landmark catheter was considered because of the advantages discussed by Mermel and coworkers and because other catheters could not be inserted. Of the drugs known to be associated with adverse events, the most common agents were Rocephin (Roche Laboratories, Nutley, New Jersey), other ß-lactams, vancomycin, and Demerol (Sanofi Winthrop, New York, New York). Some transient reactions were also associated with use of local iodine and with saline flushing. Although we strongly agree that all catheters must be carefully evaluated for safety, we view the findings of Mermel and colleagues in a different light. In fact, the small number of events, which does not appear to be associated with the unique new technology of the Landmark catheter, is reassuring.