RESUMO
BACKGROUND: Transfusion-associated hyperkalemic cardiac arrest is a serious complication in patients receiving packed red blood cell (PRBC) transfusions. Mortality from hyperkalemia increases with large volumes of PRBC transfusion, increased rate of transfusion, and the use of stored PRBCs. Theoretically, hyperkalemia may be complicated by low cardiac output, acidosis, hyperglycemia, hypocalcemia, and hypothermia. In this study, we focus on transfusion-related hyperkalemia involving only medical intensive care unit (MICU) patients. METHOD: This prospective observational study focuses on PRBC transfusions among MICU patients greater than 18 years of age. Factors considered during each transfusion included patient's diagnosis, indication for transfusion, medical co-morbidities, acid-base disorders, K(+) levels before and after each PRBC transfusion, age of stored blood, volume and rate of transfusion, and other adverse events. We used Pearson correlation and multivariate analysis for each factor listed above and performed a logistic regression analysis. RESULTS: Between June 2011 and December 2011, 125 patients received a total of 160 units of PRBCs. Median age was 63 years (22 - 92 years). Seventy-one (57%) were females. Sixty-three patients (50%) had metabolic acidosis, 75 (60%) had acute renal failure (ARF), and 12 (10%) had end-stage renal disease (ESRD). Indications for transfusion included septic shock (n = 65, 52%), acute blood loss (n = 25, 20%), non-ST elevation myocardial infarction (NSTEMI) (n = 25, 20%) and preparation for procedures (n = 14, 11%). Baseline K(+) value was 3.9 ± 1.1 mEq/L compared to 4.3 ± 1.2 mEq/L post-transfusion respectively (P = 0.9). During this study period, 4% of patients developed hyperkalemia (K(+) 5.5 mEq/L or above). The mean change of serum potassium in patients receiving transfusion ≥ 12 days old blood was 4.1 ± 0.4 mEq/L compared to 4.8 ± 0.3 mEq/L (mean ± SD) in patients receiving blood 12 days or less old. Sixty-two patients (77.5%) that were transfused stored blood (for more than 12 days) had increased serum K(+); eight (17.7%) patients received blood that was stored for less than 12 days. In both univariate (P = 0.02) and multivariate (P = 0.04) analysis, findings showed that among all factors, transfusion of stored blood was the only factor that affected serum potassium levels (95% CI: 0.32 - 0.91). No difference was found between central and peripheral intravenous access (P = 0.12), acidosis (P = 0.12), ARF (P = 0.6), ESRD (P = 0.5), and multiple transfusions (P = 0.09). One subject developed a sustained cardiac arrest after developing severe hyperkalemia (K(+) = 9.0) following transfusion of seven units of PRBCs. Multivariate logistic regression showed linear correlation between duration of stored blood and serum K(+) (R(2) = 0.889). CONCLUSION: This study assesses factors that affect K(+) in patients admitted to MICU. Results from the study show that rise in serum K(+) level is more pronounced in patients who receive stored blood (> 12 days). Future studies should focus on the use of altered storage solution, inclusion of potassium absorption filters during transfusion and cautious use of blood warmer in patients requiring massive blood transfusions.
RESUMO
INTRODUCTION: Thrombocytosis is a common disorder in patients diagnosed with iron deficiency anemia. The decreased platelet counts commonly found iron deficiency anemia is rarely reported in clinical practice. The exact mechanism of the occurrence of thrombocytopenia in iron deficiency anemia remains unclear. In this case report we discuss a triad of symptoms seen in the African American population: Iron deficiency anemia, menorrhagia and thrombocytopenia. CASE PRESENTATION: A 40 year old multiparous African-American woman presented with heavy vaginal bleed, severe anemia (3.5 g/dL) and thrombocytopenia (30,000/mm(3)). The peripheral blood smear showed marked microcytic hypochromic cells with decreased platelets counts. After excluding other causes of thrombocytopenia and anemia, increased red cell distribution width and low iron saturation confirmed the diagnosis of iron deficiency anemia. Treatment for iron deficiency anemia was initiated with intravenous and oral iron supplements. Two months following treatment of iron deficiency anemia, the triad of manifestations resolved and patient remained stable. CONCLUSION: Profound degree of iron deficiency anemia can present with thrombocytopenia and severe menorrhagia. Iron replacement should be the main treatment goal in these patients. This case report further supports the 2 compartment model of the role of iron in maintaining platelet counts.
