Methemoglobinemia Caused by Portable Dialysis in the Critically Ill.

OBJECTIVE: To evaluate the root cause of a series of methemoglobinemia cases in a medical ICU. RESULTS: We report a sentinel case of methemoglobinemia that was associated with dialysis sessions using a portable dialysis unit in our hospital. This led to the identification of four additional patients who developed methemoglobinemia while undergoing portable dialysis. We determined that these episodes were caused by inadequate clearance of chloramine from the tap water used for portable dialysis. Introduction of larger capacity carbon filters into the portable dialysis systems resulted in no further cases of methemoglobinemia at our institution. CONCLUSIONS: Clinicians should be aware of municipal tap water as a potential cause of methemoglobinemia and monitor for excessive levels of oxidants in dialysis water sources. The capacity of the hemodialysis equipment to clear chloramine can vary as a function of external factors. Using a reliable test method to identify chloramines in the water prior to entering the hemodialysis equipment is essential.

Effect of niacin therapy on cardiovascular outcomes in patients with coronary artery disease.

BACKGROUND: Niacin or nicotinic acid (vitamin B3) raises the levels of high-density lipoprotein cholesterol (HDL) by about 30% to 35%. In patients with prior coronary disease, 7 trials have been published on clinical cardiovascular disease outcomes and the results, not surprisingly, are inconsistent. Hence, we performed this meta-analysis of randomized placebo-controlled trials (RCTs) to evaluate the effect of niacin on cardiovascular outcomes in patients with coronary artery disease. METHODS: A systematic search using PubMed, EMBASE, and Cochrane library databases was performed. Seven studies with a total of 5137 patients met our inclusion criteria. Heterogeneity of the studies was analyzed by the Cochran Q statistics. The significance of common treatment effect was assessed by computing the combined relative risks using the Mantel-Haenszel fixed-effect model. A 2-sided alpha error of less than .05 was considered statistically significant (P < .05). RESULTS: Compared to placebo group, niacin therapy significantly reduced coronary artery revascularization (RR [relative risk]: 0.307 with 95% CI: 0.150-0.628; P = .001), nonfatal myocardial infarction ([MI]; RR: 0.719; 95% CI: 0.603-0.856; P = .000), stroke, and TIA ([transient ischemic attack] RR: 0.759; 95%CI: 0.613-0.940; P = .012), as well as a possible but nonsignificant decrease in cardiac mortality (RR: 0.883: 95% CI: 0.773-1.008; p= 0.066). CONCLUSIONS: In a meta-analysis of seven trials of secondary prevention, niacin was associated with a significant reduction in cardiovascular events and possible small but non-significant decreases in coronary and cardiovascular mortality.