modified St. Thomas' solution

Modified St. Thomas' solution is a hyperkalemic crystalloid cardioplegic solution used to induce and maintain cardiac arrest during open-heart surgery, providing myocardial protection by reducing metabolic demand and preventing ischemic injury[1][2]. The formulation is characterized by low sodium concentration and the inclusion of mannitol as a colloid to reduce cellular edema through its hyperosmolar properties[2]. The mechanism of action involves depolarizing cardiac myocytes via elevated extracellular potassium, which arrests the heart in diastole; low sodium further supports arrest by inhibiting fast sodium channel activity[2][3]. Mannitol helps counteract osmotic pressure changes during hypothermia and reduces myocardial cell swelling[2]. Modified versions may differ slightly in electrolyte composition but generally retain these core features.

Other names

改良St.Thomas停搏液modified St.Thomas’ Hospital cardioplegic solutionmodified St. Thomas solution