Treatment strategies for hyperkalemia secondary to urethral obstruction in 50 male cats: 2002–2017

OBJECTIVES: The aims of this study were: to describe the potassium-lowering treatment strategies used to manage moderate-to-severe hyperkalemia in male cats with urethral obstruction (UO); to determine how much dextrose was required per unit of insulin to prevent hypoglycemia; to determine whether early initiation of a dextrose continuous rate infusion (CRI) prevented hypoglycemia; and to determine whether in-hospital mortality was associated with presenting plasma potassium concentration ([K(+)]). METHODS: The medical records of male cats presenting with a [K(+)] ⩾7.0 mEq/l due to UO that had another [K(+)] measured within 6 h were reviewed retrospectively. All [K(+)] values within the first 6 h, blood glucose concentrations, treatments for hyperkalemia and survival to discharge were recorded. Analyses were performed to test for associations between dextrose:insulin ratios or method of dextrose administration and the development of hypoglycemia; and for presenting [K(+)] and mortality. Normally distributed groups of continuous data were compared with a t-test and categorical data were compared with a Fisher’s exact test. RESULTS: Fifty cats were included. Mean presenting [K(+)] was 8.9 ± 1.0 mEq/l, while the mean final [K(+)] within 6 h was 6.6 ± 1.4 mEq/l. Forty-two (84%) cats were treated with intravenous fluids and 40 (80%) were treated with dextrose and insulin. Median dextrose:insulin ratio was 2 g/u (range 0.4–100). No dextrose:insulin ratio was found to protect against hypoglycemia, and 3/8 cats that became hypoglycemic had received ⩾2 g dextrose per unit of insulin. There was no association between the early initiation of a dextrose-containing CRI and avoidance of hypoglycemia. No association was found between presenting [K(+)] and mortality. CONCLUSIONS AND RELEVANCE: While no specific dextrose:insulin ratio was found to protect against hypoglycemia, there is evidence that the commonly recommended dextrose:insulin ratio of 2 g/u may be inadequate in preventing hypoglycemia in every cat. Severity of hyperkalemia was not associated with mortality.