Manzella and colleagues did not observe the adverse reactions that we and others [1] described; however, Moorcroft and associates did, and they noted a similar incidence rate. Regarding Dr. Evans' comments, the Teflon catheters were 0.75 to 1.25 inches long and were inserted during the study period in hospitalized patients by the same nursing group that inserted the Landmark catheters.

Regarding the comments of Drs. Terr and Bloch, our patients' symptoms resembled anaphylactoid reactions associated with first use of cuprophane dialyzers; fewer than 20% had urticaria or angioedema, and symptoms resolved despite continued use of the device [2]. Similar reactions associated with Menlo Care's Streamline catheters [3]—which are inserted in the hand rather than the antecubital fossa (as with Landmark catheters)—are unlikely to be caused by localized vascular events. Our nurses were trained in catheter insertion by the manufacturer's consultants.

The patients whose blood was studied by Dr. Gershwin had urticaria, pruritus, hypotension, and abdominal and chest pain. His findings did not exclude reactions from tissue mast-cell histamine release, activation of coagulation or fibrinolysis-generating kinins (for example, bradykinin [4]), complement-activation-producing anaphylatoxins [2], or altered arachidonic acid metabolism with excess production of proinflammatory mediators.

Regarding Dr. Parisian's comments, a letter from the FDA sent to Menlo Care about the Landmark midline catheter states that "the methods used in, or the facilities or controls used for their manufacturer were not in compliance with good manufacturing practices for medical devices" [3]. Our patients' therapy could not have caused the observed adverse events, given that these events occurred before medications were administered through the catheters.

Health care workers recently received letters from Menlo Care stating that cardiac and respiratory arrests had been associated with Landmark catheters and letters from the FDA that reaffirmed our findings. An article published by the Centers for Disease Control and Prevention [5] also confirmed our findings. The adverse events probably represent anaphylactoid reactions similar to hemodialyzer reactions [2]. The lack of a known mechanism does not negate the evidence suggesting a cause-effect relation between Landmark catheter use and life-threatening adverse reactions. According to an FDA case definition of unanticipated adverse events associated with insertion of intravascular catheters, no reports in the FDA's Device Experience Network Database and Health Hazard Evaluations since 1986 have noted adverse events associated with intravascular catheters manufactured by companies other than Menlo Care [3]. The incidence of these events is 0 per 1.5 billion catheters compared with 190 per 726 000 Landmark catheters. Since we stopped using the Landmark catheter, these reactions have not been observed, despite the insertion of 263 silicone midline catheters made by another manufacturer.