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Cardioplegia serves to intentionally and temporarily arrest the heart for myocardial protection during cardiac surgery. This activity describes cardioplegia as well as outlines the various components and delivery methods and highlights the role of the interprofessional team in managing patients who require cardioplegia. Objectives: Summarize the classic indications for the use of cardioplegia in cardiac surgery patients. Describe the technique of cardioplegia. Review the appropriate evaluation of the potential complications and clinical significance of cardioplegia. Outline interprofessional team strategies for improving care coordination and communication to advance the use of cardioplegia and improve outcomes. Access free multiple choice questions on this topic.

Cardioplegia is a pharmacological therapy administered during cardiac surgery to intentionally and temporarily arrest the heart. The first solution used during cardiopulmonary bypass was reported by Dr. Melrose in the early 1950s, who identified that high levels of potassium citrate induced a reversible cardiac arrest.[1] An influx of potassium depolarizes the myocardial membrane causing contraction and thus release and subsequent sequestration of calcium ions resulting in a diastolic arrest. The resting membrane potential in myocytes is about -85 mV, and with the influx of sodium ions, depolarization occurs (membrane becomes more positive -45 to -30 mV) and thus generating an action potential that is potentiated by L-type calcium channels. These voltage-gated channels are targeted with cardioplegia to induce cardiac arrest.[2] The persistence of potassium reduces the membrane potential and does not allow for adequate repolarization. This, in turn, creating a diastolic cardiac arrest. As the solution diffuses and there is a washout of its components along with products of anaerobic cellular metabolism, electrical activity begins to appear, and redosing of cardioplegia is required if clinically indicated. Potassium, however, is not the only ion commonly found in cardioplegia. Other ions such as calcium, sodium, and magnesium all participate in reducing contractility and preserving the myocardium. Additionally, components such as lidocaine, bicarb, and even glucose may be added for further protection.[3] Cardioplegia is an essential component of cardiopulmonary bypass and with the primary goal to reduce myocardial oxygen demand by creating electrical quiescence and cooling the heart to reduce the ischemic effects of being on bypass. The use of cardioplegia, in addition to being cardioprotective, also provides a relatively bloodless and motionless surgical field. There are many forms of cardioplegia ranging from the location of administration retrograde vs. antegrade as well as varying components within the solution, temperature, indications, adverse effects, pharmacokinetics, and pharmacodynamics.

Cardioplegia following aortic cross-clamping results in many physiological changes that may hinder the recovery of the myocardium. It is essential to understand the electrolyte abnormalities, myocardial stunning, pH imbalance that may occur secondary to cardioplegia administration. Before coming off cardiopulmonary bypass, electrolytes, temperature, glucose, pH, hemoglobin, and hematocrit must be within normal limits. Excessive physiological changes may result in myocardial stunning, arrhythmias, ischemic injury leading to the inability to wean from cardiopulmonary bypass. Prophylactic measures are taken to reduce the complications of cardioplegia, such as frequent blood sampling by the perfusionist and notifying the surgeon and anesthesiologist of derangements while treating abnormalities as they present.

The safe use of cardioplegia during cardiac surgery requires a team approach and excellent interprofessional communication. With numerous moving parts encountered during open-heart surgery and the use of the cardiopulmonary bypass machine, it is of utmost importance for physicians, perfusionists, nurses, and surgical assistance to pay close attention and speak up should an issue arise. A designated heart team that practices and works together can make for improved patient safety and better patient outcomes. Close-loop feedback is used during critical times between the cardiac surgeon and perfusionist to diminish any room for error. As previously noted, cardioplegia solutions vary, and to date, there are no evidence-based guidelines regarding the administration of cardioplegia during cardiac surgery. As illustrated by the 2011 ACCF/AHA Guideline for CABG Surgery, reductions in reperfusion injury or surgically induced systemic inflammatory response by way of pharmacological agents or controlled reperfusion strategies that seek to induce myocardial preconditioning have not been proven, and their benefits remain uncertain.[20] [Class IIb, Level A evidence] Thus, further clinical studies are needed to reach a consensus of best practices regarding cardioplegia and myocardial preservation.