Methemoglobinemia in Hemodialysis Patients due to Acute Chlorine Intoxication: A Case Series Calling Attention on an Old Problem.

INTRODUCTION: Hemodialysis uses municipal water that must be strictly purified and sterilized to be used for that procedure. Large amounts of decontaminants are often used, such as chlorine, and if these compounds are not subsequently removed they can be transferred to the blood of patients causing complications including methemoglobinemia. METHODS: In this case series study, dialysis patients in one unit were evaluated. We reviewed clinical characteristics and laboratory findings obtained on the day when the water supply was disinfected with chlorine, with the aim to quantify methemoglobin concentrations. Our objective was to characterize the clinical presentation and management of patients who presented with methemoglobinemia on a specific index day. We also reviewed reported cases in the literature regarding this underreported complication. RESULTS: Eight patients who presented with chlorine intoxication were evaluated. The methemoglobin concentrations were between 1.3% and 7.9% (reference value 0-1%). We believe this to be caused by water containing 0.78 mg/L of total chlorine. Seven patients presented with cyanosis, 4 with dizziness, 6 with dark brown blood, 4 with dyspnea, and 4 with headache and hemolytic anemia. Subjects were treated with supplemental oxygen, methylene blue, intravenous vitamin C, blood transfusions, and increased doses of erythropoietin. No patient died, and all continued with their usual hemodialysis sessions. CONCLUSION: Acute chlorine intoxication transferred by the water used during hemodialysis sessions can present with methemoglobinemia accompanied by cyanosis, oxygen desaturation, and hemolytic anemia. Chlorine levels should be carefully monitored in the water used for hemodialysis treatment.

Urea Reduction in Acute Kidney Injury and Mortality Risk.

INTRODUCTION: Urea is a toxin present in acute kidney injury (AKI). We hypothesize that reduction in serum urea levels might improve clinical outcomes. We examined the association between the reduction in urea and mortality. METHODS: Patients with AKI admitted to the Hospital Civil de Guadalajara were enrolled in this retrospective cohort study. We create 4 groups of urea reduction ratio (UXR) stratified by their decrease in urea from the highest index value in comparison to the value on day 10 (0%, 1-25%, 26-50%, and >50%), or at the time of death or discharge if prior to 10 days. Our primary endpoint was to observe the association between UXR and mortality. Secondary observations included determination of which types of patients achieved a UXR >50%, whether the modality of kidney replacement therapy (KRT) effected changes in UXR, and if serum creatinine (sCr) value changes were similarly associated with patient mortality. RESULTS: A total of 651 AKI patients were enrolled. The mean age was 54.1 years, and 58.6% were male. AKI 3 was present in 58.5%; the mean admission urea was 154 mg/dL. KRT was started in 32.4%, and 18.9% died. A trend toward decreased risk of death was observed in association with the magnitude of UXR. The best survival (94.3%) was observed in patients with a UXR >50%, and the highest mortality (72.1%) was observed in patients achieving a UXR of 0%. After adjusting for age, sex, diabetes mellitus, CKD, antibiotics, sepsis, hypovolemia, cardio-renal syndrome, shock, and AKI stage, the 10-day mortality was higher in groups that did not achieve a UXR of at least 25% (OR: 1.20). Patients achieving a UXR >50% were most likely initiated on dialysis due to a diagnosis of the uremic syndrome or had a diagnosis of obstructive nephropathy. Percentage change in sCr was also associated with increased mortality risk. CONCLUSIONS: In our retrospective cohort of AKI patients, the percent decrease in UXR from admission was associated with a stratified risk of death. Patients with a UXR >25% had the best associated outcomes. Overall, a greater magnitude in UXR was associated with improved patient survival.

[Reliability of an automatic monitor for blood pressure measurement]. / Confiabilidad de un monitor automatizado para la medición de la presión arterial.

Background A correct blood pressure (BP) measurement is essential for the diagnosis and control of high BP. AIM: To evaluate the agreement and repeatability of BP measurements with the OMRON HEM-7320-LA device compared to a mercury sphygmomanometer. MATERIAL AND METHODS: A cross-sectional study comparing BP measurements made by two randomly selected trained nurses and an automatic oscillometric device. The mercurial sphygmomanometer was connected to the automated device via a "T" type connector and a dual-head stethoscope was used, allowing simultaneous measurements. The results were analyzed with one-factor analysis of variance, Bland-Altman's test, repeatability coefficient (RC), and intra-class correlation coefficient (ICC). RESULTS: Forty-nine participants aged 56 ± 19 years were included. Nineteen had hypertension (38%). We did not observe a significant difference in either systolic (SBP) or diastolic blood pressure (DBP) pressure measurements between the observers and the device. The mean difference was -0.09 mmHg (95% confidence intervals (CI)-0.9 to 0.7) for SBP and -0.9 mmHg (95% CI -1.7 to -0.13) for DBP. The RC for SBP (6.2, 5.2 and 5.8 mmHg) and DBP (4.7, 4.2 y 5.2 mmHg) was similar between the observers and the device. The ICC for SBP was 0.990 (95% CI 0.983 to 0.995, p < 0.01) and 0.986 (95% CI 0.977 to 0.991, p < 0.01) for DBP. CONCLUSIONS: There was a high level of agreement and similar measurement repeatability in the measurements performed by the automatic device and the mercurial sphygmomanometer. No differences in BP measurements were observed.

Confiabilidad de un monitor automatizado para la medición de la presión arterial / Reliability of an automatic monitor for blood pressure measurement

Background A correct blood pressure (BP) measurement is essential for the diagnosis and control of high BP. Aim: To evaluate the agreement and repeatability of BP measurements with the OMRON HEM-7320-LA device compared to a mercury sphygmomanometer. Material and Methods: A cross-sectional study comparing BP measurements made by two randomly selected trained nurses and an automatic oscillometric device. The mercurial sphygmomanometer was connected to the automated device via a "T" type connector and a dual-head stethoscope was used, allowing simultaneous measurements. The results were analyzed with one-factor analysis of variance, Bland-Altman's test, repeatability coefficient (RC), and intra-class correlation coefficient (ICC). Results: Forty-nine participants aged 56 ± 19 years were included. Nineteen had hypertension (38%). We did not observe a significant difference in either systolic (SBP) or diastolic blood pressure (DBP) pressure measurements between the observers and the device. The mean difference was −0.09 mmHg (95% confidence intervals (CI)-0.9 to 0.7) for SBP and −0.9 mmHg (95% CI −1.7 to −0.13) for DBP. The RC for SBP (6.2, 5.2 and 5.8 mmHg) and DBP (4.7, 4.2 y 5.2 mmHg) was similar between the observers and the device. The ICC for SBP was 0.990 (95% CI 0.983 to 0.995, p < 0.01) and 0.986 (95% CI 0.977 to 0.991, p < 0.01) for DBP. Conclusions: There was a high level of agreement and similar measurement repeatability in the measurements performed by the automatic device and the mercurial sphygmomanometer. No differences in BP measurements were observed.