Medstar Washington Hospital Center, Department of Emergency Medicine, Washington DC.
West J Emerg Med. 2020 Oct 20;21(6):272-275. doi: 10.5811/westjem.2020.8.46812.
In the emergency department (ED), pseudohyperkalemia from hemolysis may indirectly harm patients by exposing them to increased length of stay, cost, and repeat blood draws. The need to repeat hemolyzed potassium specimens in low-risk patients has not been well studied. Our objective was to determine the rate of true hyperkalemia among low-risk, adult ED patients with hemolyzed potassium specimens.
We conducted this prospective observational study at two large (129,000 annual visits) academic EDs in the mid-Atlantic. Data were collected from June 2017-November 2017 as baseline data for planned departmental quality improvement and again from June 2018-November 2018. Inclusion criteria were an initial basic metabolic panel in the ED with a hemolyzed potassium level > 5.1 milliequivalents per liter that was repeated within 12 hours, age (≥18, and bicarbonate (HCO) > 20. Exclusion criteria were age > 65, glomerular filtration rate (GFR) < 60, creatine phosphokinase > 500, hematologic malignancy, taking potassium-sparing or angiotensin-acting agents, or treatment with potassium-lowering agents (albuterol, insulin, HCO, sodium polystyrene sulfonate, or potassium-excreting diuretic) prior to the repeat lab draw.
Of 399 encounters with a hemolyzed, elevated potassium level in patients with GFR ≥ 60 and age > 18 that were repeated, we excluded 333 patients for age > 64, lab repeat > 12 hours, invalid identifiers, potassium-elevating or lowering medicines or hematologic malignancies.This left 66 encounters for review. There were no instances of hyperkalemia on the repeated, non-hemolyzed potassium levels, correlating to a true positive rate of 0% (95% confidence interval 0-6%). Median patient age was 46 (interquartile range [IQR] 34 - 56) years. Median hemolyzed potassium level was 5.8 (IQR 5.6 - 6.15) millimoles per liter (mmol/L), and median repeated potassium level was 3.9 (IQR 3.6 - 4.3) mmol/L. Median time between lab draws was 145 (IQR 87 - 262) minutes.
Of 66 patients who met our criteria, all had repeat non-hemolyzed potassiums within normal limits. The median of 145 minutes between lab draws suggests an opportunity to decrease the length of stay for these patients. Our results suggest that in adult patients < 65 with normal renal function, no hematologic malignancy, and not on a potassium-elevating medication, there is little to no risk of true hyperkalemia. Further studies should be done with a larger patient population and multicenter trials.
在急诊科（ED），溶血引起的假性高钾血症可能会通过延长患者的住院时间、增加成本和重复采血而间接危害患者。在低危患者中，需要重复检测溶血的钾标本尚未得到很好的研究。我们的目的是确定低危、成年 ED 患者中溶血的钾标本中真正高钾血症的发生率。
我们在大西洋中部的两家大型（每年就诊 129000 人次）学术 ED 进行了这项前瞻性观察性研究。数据收集时间为 2017 年 6 月至 2017 年 11 月，作为计划中的部门质量改进的基线数据，并于 2018 年 6 月至 2018 年 11 月再次收集。纳入标准为 ED 初始基本代谢谱中钾水平> 5.1 毫当量/升且溶血，在 12 小时内重复，年龄（≥ 18 岁，碳酸氢盐（HCO）> 20。排除标准为年龄> 65 岁，肾小球滤过率（GFR）< 60，肌酸磷酸激酶> 500，血液恶性肿瘤，服用保钾或血管紧张素作用药物，或在重复实验室检测前使用降低血钾的药物（沙丁胺醇、胰岛素、HCO、聚苯乙烯磺酸钠或排钾利尿剂）。
在 399 例 GFR≥60 且年龄>18 岁的患者中，对升高的、溶血的钾水平进行了重复检测，我们排除了 333 例患者，原因是年龄> 64 岁、实验室重复检测> 12 小时、无效标识符、升高或降低血钾的药物或血液恶性肿瘤。这剩下 66 次就诊进行复查。在重复的非溶血钾水平上，没有高钾血症的病例，这与真阳性率为 0%（95%置信区间 0-6%）相对应。患者的中位年龄为 46（四分位距[IQR]34-56）岁。中位溶血钾水平为 5.8（IQR 5.6-6.15）毫摩尔/升（mmol/L），重复钾水平为 3.9（IQR 3.6-4.3）mmol/L。两次实验室检测之间的中位时间为 145（IQR 87-262）分钟。
在符合我们标准的 66 例患者中，所有患者的重复非溶血钾均在正常范围内。两次实验室检测之间 145 分钟的中位数表明，这些患者的住院时间可能会缩短。我们的结果表明，在肾功能正常、无血液恶性肿瘤且未服用升高血钾药物的< 65 岁成年患者中，真正高钾血症的风险很小或不存在。应在更大的患者人群中进行进一步的研究，并进行多中心试验。
