title: A prospective study on red blood cell transfusion related hyperkalemia in critically ill patients.
abstract: 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.
  
  
  METHODS
  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).
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Internal Medicine, Brookdale University Hospital & Medical Center, 1 Brookdale Plaza, Brooklyn, New York, NY 11212, USA ; University of Missouri Columbia, Ellis Fischel Cancer Center, Columbia, Missouri, MO 65212, USA.
authors.forename: Shahzad
authors.initials: S
authors.lastname: Raza
authors.affiliation: Albert Einstein School of Medicine, Montefiore Medical Center, 111 East 210th Street, Bronx, NY 10467, USA.
authors.forename: Mahadi
authors.initials: M
authors.lastname: Ali Baig
authors.affiliation: Department of Internal Medicine, Brookdale University Hospital & Medical Center, 1 Brookdale Plaza, Brooklyn, New York, NY 11212, USA.
authors.forename: Christopher
authors.initials: C
authors.lastname: Chang
authors.affiliation: Department of Internal Medicine, Brookdale University Hospital & Medical Center, 1 Brookdale Plaza, Brooklyn, New York, NY 11212, USA.
authors.forename: Ridhima
authors.initials: R
authors.lastname: Dabas
authors.affiliation: Department of Internal Medicine, Brookdale University Hospital & Medical Center, 1 Brookdale Plaza, Brooklyn, New York, NY 11212, USA.
authors.forename: Mallika
authors.initials: M
authors.lastname: Akhtar
authors.affiliation: Department of Internal Medicine, Brookdale University Hospital & Medical Center, 1 Brookdale Plaza, Brooklyn, New York, NY 11212, USA.
authors.forename: Areej
authors.initials: A
authors.lastname: Khan
authors.affiliation: Department of Internal Medicine, Brookdale University Hospital & Medical Center, 1 Brookdale Plaza, Brooklyn, New York, NY 11212, USA.
authors.forename: Krishna
authors.initials: K
authors.lastname: Nemani
authors.affiliation: Department of Internal Medicine, Brookdale University Hospital & Medical Center, 1 Brookdale Plaza, Brooklyn, New York, NY 11212, USA.
authors.forename: Rahima
authors.initials: R
authors.lastname: Alani
authors.affiliation: Department of Internal Medicine, Brookdale University Hospital & Medical Center, 1 Brookdale Plaza, Brooklyn, New York, NY 11212, USA.
authors.forename: Omran
authors.initials: O
authors.lastname: Majumder
authors.affiliation: Department of Internal Medicine, Brookdale University Hospital & Medical Center, 1 Brookdale Plaza, Brooklyn, New York, NY 11212, USA.
authors.forename: Natalya
authors.initials: N
authors.lastname: Gazizova
authors.affiliation: Department of Internal Medicine, Brookdale University Hospital & Medical Center, 1 Brookdale Plaza, Brooklyn, New York, NY 11212, USA.
authors.forename: Shaluk
authors.initials: S
authors.lastname: Biswas
authors.affiliation: Department of Internal Medicine, Brookdale University Hospital & Medical Center, 1 Brookdale Plaza, Brooklyn, New York, NY 11212, USA.
authors.forename: Priyeshkumar
authors.initials: P
authors.lastname: Patel
authors.affiliation: Department of Internal Medicine, Brookdale University Hospital & Medical Center, 1 Brookdale Plaza, Brooklyn, New York, NY 11212, USA.
authors.forename: Jaffar A
authors.initials: JA
authors.lastname: Al-Hilli
authors.affiliation: Department of Internal Medicine, Brookdale University Hospital & Medical Center, 1 Brookdale Plaza, Brooklyn, New York, NY 11212, USA.
authors.forename: Yasar
authors.initials: Y
authors.lastname: Shad
authors.affiliation: Department of Internal Medicine, Brookdale University Hospital & Medical Center, 1 Brookdale Plaza, Brooklyn, New York, NY 11212, USA.
authors.forename: Barbara J
authors.initials: BJ
authors.lastname: Berger
authors.affiliation: Department of Internal Medicine, Brookdale University Hospital & Medical Center, 1 Brookdale Plaza, Brooklyn, New York, NY 11212, USA.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Zaman
keywords: Hyperkalemia; Packed red blood cell transfusion; Potassium; Red cell storage