Lactated Ringer's solution and risk of hyperkalemia in patients with reduced kidney function.

BACKGROUND: Emerging evidence supports the superiority of balanced crystalloids such as Lactated Ringer's (LR) compared to normal saline but concerns for the development of hyperkalemia have limited its use. Although LR inherently contains potassium, there exists a paucity of evidence to suggest that LR could potentiate hyperkalemia. To address this, we evaluated the effect of LR on serum potassium in patients with reduced kidney function who are at risk of developing hyperkalemia. METHODS: We conducted a single-center, retrospective cohort-based observational clinical study that included 293 clinical encounters who were hospitalized with an estimated glomerular filtration rate (eGFR) of < 30 ml/min/1.73m2, at the time of hospital admission. Subjects must have received a minimum of 500 ml of LR continuously during the admission. Only those with a minimum of one lab report within 24 hours prior to-, and post-LR administration that reported serum measurements of potassium, glucose, and bicarbonate levels were included. Other potential risk factors for developing hyperkalemia including medication, tube feeds, potassium supplements, and red blood cell transfusion during or within 24 hours after LR administration were recorded. RESULTS: Serum potassium prior to LR use was highly correlated and predictive of the serum potassium after LR use [P < 0.0001; Odds Ratio 6.77 (3.73 - 12.28)]. Sixteen encounters (5%) developed de-novo hyperkalemia following LR use. No significant positive correlation between the amount of LR administered and the development of hyperkalemia was found. CONCLUSIONS: LR use was not independently associated with the development of hyperkalemia in patients with reduced kidney function.

Differentiating SIADH from Cerebral/Renal Salt Wasting: Failure of the Volume Approach and Need for a New Approach to Hyponatremia.

Hyponatremia is the most common electrolyte abnormality. Its diagnostic and therapeutic approaches are in a state of flux. It is evident that hyponatremic patients are symptomatic with a potential for serious consequences at sodium levels that were once considered trivial. The recommendation to treat virtually all hyponatremics exposes the need to resolve the diagnostic and therapeutic dilemma of deciding whether to water restrict a patient with the syndrome of inappropriate antidiuretic hormone secretion (SIADH) or administer salt and water to a renal salt waster. In this review, we briefly discuss the pathophysiology of SIADH and renal salt wasting (RSW), and the difficulty in differentiating SIADH from RSW, and review the origin of the perceived rarity of RSW, as well as the value of determining fractional excretion of urate (FEurate) in differentiating both syndromes, the high prevalence of RSW which highlights the inadequacy of the volume approach to hyponatremia, the importance of changing cerebral salt wasting to RSW, and the proposal to eliminate reset osmostat as a subtype of SIADH, and finally propose a new algorithm to replace the outmoded volume approach by highlighting FEurate. This algorithm eliminates the need to assess the volume status with less reliance on determining urine sodium concentration, plasma renin, aldosterone and atrial/brain natriuretic peptide or the BUN to creatinine ratio.