Restrictive Potassium Supplementation Strategy in a General Intensive Care Unit: A Before-and-After Quality Improvement Audit in a Mixed Critical Care Population

Purpose: Potassium supplementation thresholds in intensive care vary widely and have historically lacked strong supporting evidence.The TIGHT K trial demonstrated non-inferiority of a restrictive potassium threshold in cardiac surgical patients; applicability to general intensive care populations is unclear.Methods: Retrospective before-and-after quality improvement audit in a mixed adult intensive care unit (ICU), comparing two one-week periods before (May 2025) and after (September 2025) reducing the intravenous potassium supplementation threshold from <4.5 to <3.6 mmol/L.Results: Forty-eight patients were included (22 pre-, 26 post-guideline) with comparable baseline characteristics.Mean intravenous potassium administrations per patient fell by 17.4% (from 9.41 to 7.77 administrations per patient), and the proportion of supplementation episodes initiated at K⁺ ≥4.0 mmol/L fell from 32.9% to 11.4% (a 21.5 percentage-point absolute reduction, equivalent to a 65.2% relative reduction).Pre-supplementation potassium was lower post guideline (3.44 vs 3.83 mmol/L; p <0.001), but potassium correction (ΔK) was unchanged (p = 0.51), and arrhythmia burden did not increase.Conclusion: A restrictive potassium supplementation threshold reduced potassium use without evidence of harm in a general intensive care population, supporting wider applicability beyond cardiac surgery, although larger prospective studies are needed.