Magnesium ion (Mg2+)

Magnesium ion (Mg2+) is the second most abundant intracellular cation and serves as a mandatory cofactor for over 300 enzymatic reactions, particularly those involving ATP transfer (StatPearls, 2023). In clinical settings involving extracorporeal circuits, such as continuous renal replacement therapy (CRRT) or cardiopulmonary bypass, magnesium is a critical analyte for monitoring and intervention (PubMed, PMID: 28934562). During regional citrate anticoagulation (RCA), citrate is infused into the circuit to chelate magnesium and calcium, effectively lowering their ionized concentrations to inhibit the clotting cascade (NIH, 2022). This necessitates careful monitoring and replacement of magnesium to prevent systemic hypomagnesemia, which can lead to life-threatening arrhythmias and neuromuscular irritability. Conversely, patients with renal failure are at risk for hypermagnesemia, making magnesium a central target for titration in dialysate and replacement fluids (Journal of Critical Care, 2020). Magnesium also plays a role in vascular tone and platelet function, which are relevant during extracorporeal circulation. Therapeutic management often involves the use of magnesium salts to maintain levels within a narrow physiological range.

Other names

MagnesiumMg++Ionized magnesiumMagnesium(2+)

Magnesium acts as a mandatory cofactor for ATP-dependent enzymes and modulates voltage-gated calcium channels. In extracorporeal circuits, it is chelated by citrate to reduce the ionized fraction, which helps inhibit the coagulation cascade, and is subsequently managed via replacement fluids to maintain systemic homeostasis (PubMed, PMID: 31454321).