Potassium and Cardiac Surgery

Abstract

Potassium homeostasis affects cardiac rhythm and contractility, along with vascular reactivity and vascular smooth muscle proliferation. This chapter will focus on potassium dynamics during and after cardiac surgery involving cardioplegic arrest and cardiopulmonary bypass (CPB). Hyperkalemic, hypothermic solutions are frequently used to induce cardioplegic arrest and protect the heart during cardiac surgery involving CPB. Common consequences of hyperkalemic cardioplegic arrest and reperfusion include microvascular dysfunction involving several organ systems and myocardial dysfunction. Immediately after CPB, blood potassium levels often drop precipitously due to a variety of factors, including CPB -induced electrolyte depletion and frequent, long-term administration of insulin during and after surgery. Meanwhile, some patients with pre-existing kidney dysfunction may experience postoperative hyperkalemia following cardioplegia. Any degree of postoperative hyper/hypokalemia significantly elevates the risk of cardiac arrythmias and subsequent myocardial failure. Therefore, proper management of blood potassium levels during and after cardioplegia/CPB is crucial for optimizing patient outcomes following cardiac surgery.

Theoretical and Practical Aspects in the Use of Bretschneider Cardioplegia

“…These complex histopathological alterations are consequences of functional and structural endothelial damage. The coronary system is exposed to ROS, inflammatory response, and hyperkalemic agents [ 20 , 21 ]. There is a direct imbalance between endothelium-derived constricting factors: endothelin-1 (ET-1) and thromboxane A2 (TXA2), and relaxing elements, such as nitric oxide (NO) or endothelial-derived hyperpolarizing factor (EDHF), disturbing the synergistically-acting mechanisms between them [ 22 ].…”