The Effect of Diluent pH on Bloodstream Infection Rates in Patients Receiving IV Treprostinil for Pulmonary Arterial Hypertension

Background: Recent studies have reported an increase in catheter-related bloodstream infections (BSIs) and gram-negative BSIs among patients with pulmonary arterial hypertension treated with IV treprostinil. One possible explanation is the neutral pH of the treprostinil diluent compared with the basic pH of epoprostenol. We hypothesized that administering IV treprostinil with epoprostenol diluent will lower the rate of gram-negative BSI. Methods: We prospectively enrolled patients treated with IV treprostinil and changed the diluent from native diluent to epoprostenol diluent. We compared the incidence of BSI and gram-negative BSI between those receiving IV treprostinil with epoprostenol diluent (n = 25) and those actively receiving IV epoprostenol (n = 61), as well as with a cohort of patients who received IV treprostinil in native diluent (n = 34). Incidence rates of BSI were expressed as a fraction of 1,000 medicine treatment days. Results: There were similar rates of BSI in those treated with treprostinil with epoprostenol diluent and those treated with epoprostenol (0.32 of 1,000 vs 0.40 of 1,000; P = .79). Also, there were similar rates of gram-negative BSI in these two cohorts (0.08 of 1,000 vs 0.20 of 1,000; P = .46). BSI rates were not statistically different between those treated with treprostinil with epoprostenol diluent and those treated with treprostinil (0.32 of 1,000 vs 0.90 of 1,000; P = .06). However, gram-negative BSIs were significantly lower in patients treated with treprostinil with epoprostenol diluent than in those treated with treprostinil (0.08 of 1,000 vs 0.71 of 1,000, respectively; P = .01). Conclusions: Patients treated with treprostinil with epoprostenol diluent have a lower incidence of gram-negative BSI than do those treated with treprostinil and a similar rate to those treated with epoprostenol. Changing the diluent of treprostinil to epoprostenol diluent, in combination with the use of water-tight seals throughout the delivery system, appears to be an effective safety measure. CHEST 2012; 141(1):36-42