The Impact of Tris-Hydroxymethyl Aminomethane on Electrolytes During Treatment of Severe Acidosis in ARDS

Abstract

Background: Rapid infusion of THAM is known to cause severe alterations in serum electrolytes at higher doses and in the presence of either severe respiratory acidosis or renal impairment. THAM can cause hyponatremia and hyperkalemia, as well as hypoglycemia, and hypophosphatemia associated with increased insulin release and activity. We inquired as to the incidence and severity of electrolyte disturbances during the treatment of acidosis in severe ARDS.

Methods: The SFGH ARDS quality assurance database was queried to identify subjects treated with THAM from September 2006-August 2016. Of the 97 subjects identified, 82 met inclusion criteria: 1) standard bolus infusion of at least 1 full dose of THAM (150 mmol), and 2) pre-post electrolyte panels measured < 4 h of therapy initiation/completion. Data are presented as median [IQR]. Paired comparisons were made using the Wilcoxon Signed-Rank Test. Alpha was set at 0.05.

Results: A total of 143 discreet treatments met inclusion criteria. THAM was infused at 2.04 [1.61, 2.36] mmol/kg/h over 60 [60, 60] min. Paired comparisons in electrolytes were made within a total pre-post time difference (h:min) of 5:45 [4:00, 7:40]. Differences in the primary variables of interest such as potassium (K+), glucose and phosphate (PO4-) were not statistically significant. However, in 15% of comparisons K+ increased > 1 mEq/L and in 6% of these cases post-treatment K+ was > 6 mEq/L. Glucose decreased by > 100 mg/dL in 9% of comparisons and by 50-99 mg/dL in an additional 9%. In 32% of comparisons, chloride decreased > 4 mEq/L which mirrored an increased serum CO₂ of > 4mEq/L in 33% of comparisons. Paradoxically, serum lactate increased despite decreasing anion gap. This may have reflected the clinical trajectory in the subset of moribund subjects in whom THAM was used as rescue therapy.

Conclusions: At recommended infusion rates (ie, < 5 mmol/kg over 1 h), 1 THAM had minor impact on electrolytes. However, in a minority of ARDS subjects with severe acidosis, infusion of THAM did result in acute hyperkalemia and hypoglycemia. Careful monitoring of serum electrolytes is warranted prior to and following administration.

1. Nahas GG, Sutin KM, Fermon C. Guidelines for the treatment of acidemia with THAM. Drugs 1998;55:191-224.