A couple of weeks ago,I blogged on the cardiothoracic cases that I have observed.. Since then I have been continously amazed as to how the myocardium is completely paralyzed before it is operated...Before any resection on the heart is performed, the heart is completely stopped(paralyzed) and the bypass machine is tasked to pump and oxygenate blood in the body. Here's what I have just learned about Cardioplegic Solutions...
Cardioplegia in Latin cardio means heart and plegia means paralysis. Therefore, cardioplegic solution is a solution that paralyzes the heart. The solution is mixed with blood and infused into the coronary circulation to induce and maintain paralysis while the heart is being operated on. Perfusion of cardioplegic solution through heart stops the myocardium contraction/ relaxation, reducing its metabolic requirements. During this paralysis period, the heart is uniquely endowed with anaerobic pathways that it uses for energy production. To reduce the body's( heart and brain mainly) metabolic demands, the temp. is dropped from 37.5 to 22 degrees celsius and the heart is injected with the cardioplegic solutions every 40 mins for upto 120 mins. This temp. drop is known to reduce the rate of ischemia by 50%, which is a great thing! Plegisol Solution is a combination of calcium chloride dihydrate, magnesium chloride hexahydrate, potassium chloride, and sodium chloride...Once the mycardium has been sutured and the normal intracellular/extracellular re-established, and the heart starts beating again! Amazing stuff..
Next time you come across this phrase remember heart paralysis!