Hyperkalemia is common in patients receiving maintenance hemodialysis. Severe hyperkalemia in hemodialysis patients can cause fatal arrhythmias. This study aimed to assess the need for extra hemodialysis in patients with hyperkalemia before their next scheduled dialysis session. A retrospective study was conducted on hemodialysis patients with severe hyperkalemia who underwent extra-hemodialysis between March 2021 and February 2024. A total of 1,434 patients with potassium levels ≥6.5 mmol/L underwent 4,297 sessions. Of these, 535 patients (670 sessions) had consecutive daily potassium measurements. Among these sessions, 255 had initial potassium levels of 6.5-7.0 mmol/L, 189 had 7.0-7.5 mmol/L, 101 had 7.5-8.0 mmol/L, and 125 had >8.0 mmol/L. Overall, 40.4% of patients had potassium levels ≥5.5 mmol/L the following day, and 5.5% exhibited levels ≥6.5 mmol/L. Higher baseline potassium levels correlated with higher potassium levels the next day (Figure 1A). While the percentage of patients with next-day potassium >6.5 mmol/L was 5.5% overall, this increased to 27.7% in patients with initial potassium >8.5 mmol/L (Figure 1B). Forty percent of hemodialysis patients with severe hyperkalemia present with potassium levels ≥5.5 mmol/L the following day, even after hemodialysis. Consecutive extra-hemodialysis may be beneficial for patients with severely elevated potassium.