A brief history of the use of calcium to treat hyperkalemia – The Curious Clinicians
Highlights
- Sidney Ringer’s 1883 paper is one the earliest (if not the earliest) to describe the benefits of calcium in hyperkalemia
- 5% NaCl protects against the otherwise fatal effect of potassium chloride
- That calcium “increased the frequency of ventricular contractions” suggests that the cardiac membrane becomes less stable (i.e., more excitable)
- there are at least two ways that calcium might stabilize the cardiac membrane: Calcium might “undo” the increase in resting membrane potential (RMP) that hyperkalemia causes. This would mean returning the RMP to a more negative value (possibly back to -90 mV). Calcium might decrease the threshold potential. This would move it further away from the resting potential, making the cardiac membrane less excitable.
A Brief History of the Use of Calcium to Treat Hyperkalemia – The Curious Clinicians
Highlights
- more depolarization was required in calcium-rich solutions. While the RMP was unchanged, the threshold potential had increased. Weidmann concluded that this increase in the threshold potential is what “accounts for the ‘stabilizing’ effect of Ca.”
- depolarizing effect of high K is decreased by elevated Ca and the depolarization produced by low K is diminished by low levels of Ca
- 5% saline improved the ECG in 4 patients with hyperkalemia
- rising velocity (Phase 0) is significantly faster when the sodium concentration is increased.
A brief history of the use of calcium to treat hyperkalemia – The Curious Clinicians
Highlights
- Sidney Ringer’s 1883 paper is one the earliest (if not the earliest) to describe the benefits of calcium in hyperkalemia
- 5% NaCl protects against the otherwise fatal effect of potassium chloride
- That calcium “increased the frequency of ventricular contractions” suggests that the cardiac membrane becomes less stable (i.e., more excitable)
- there are at least two ways that calcium might stabilize the cardiac membrane: Calcium might “undo” the increase in resting membrane potential (RMP) that hyperkalemia causes. This would mean returning the RMP to a more negative value (possibly back to -90 mV). Calcium might decrease the threshold potential. This would move it further away from the resting potential, making the cardiac membrane less excitable.