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Video transcript

ventricular systole and pulseless electrical activity are two types of cardiac arrest meaning the heart has stopped and both of these a patient doesn't have a pulse meaning that they're not pumping blood to the rest of the body and that's why both of these conditions are absolutely fatal unless they're corrected immediately so in ventricular asystole there's no electrical activity and the heart if there's no electrical activity that means that the ventricle walls are contracting and that's what asystole basically means a means no in Sicily implies ventricular contractions so no ventricular contractions again no electrical activity means no particular contractions means no cardiac output or in other words there's no blood flow to the rest of the body so there's no cardiac output and without cardiac output you're not going to have a pulse so anybody who has particularly systole will not have a pulse and on EKG this looks like a flatline because there's no electrical activity to cause any movement on EKG and this is a flatline that you hear about on movies and TV shows and they say the patient's flatlining it's asystole and then there's pulseless electrical activity and this is known as P E a and P a there is electrical activity on EKG however it does result in a pulse and the electrical activity you see on EKG could be something that normally produces a pulse such as normal sinus rhythm or even heart block or sinus bradycardia but for some reason there's not a pulse now how could this be well in a normal heart the heart's electrical activity causes the muscle cells to contract so you have action potentials that propagate or run to the heart and they'll lead to muscle contraction and this relationship between electrical activity and mechanical contraction is called electromechanical coupling however when the heart is under extreme stress so say the hearts been pride of oxygen for a long time this system gets disconnected so even though there's electrical activity it's not going to lead to contractions because we've disconnected the system and this is called electromechanical uncoupling so despite the fact that cells can undergo and propagate action potentials the action potentials don't result in muscle contraction another reason why you could have electoral activity without a pulse is because there could be something blocking the heart now the heart has a sac outlining it called the pericardium and in some cases this might be full of blood and if it is full of blood it's going to press down on the heart and the heart shock have any room to pump this is called tamponade our cardiac tamponade and again this is a condition where the heart is constricted by this fluid-filled sac around the heart and the heart can't pump so even though you can have action potentials and electro activity in the heart you're not going to be able to pump and you won't have a pulse okay so I'm sure you've seen in movies or TV shows where someone flatlines or has asystole and someone else comes running to the room puts paddles on the chest and yells clear in this case they're defibrillating the patient meaning they're providing electrical shocks to the heart hopefully convert the heart back to a normal rhythm however this is a common misconception we never shock a systole or PA for that matter defibrillation only works on very specific abnormal cardiac rhythms that can potentially be reversed with electric shock and these are called shockable rhythms shockable rhythms include ventricular fibrillation where the walls of the ventricles are spasming and therefore they can't contract and you're not going to circulate blood to the rest of the body and pulseless ventricular tachycardia meaning that there is some sort of abnormal conduction in the ventricles that cause the ventricle is to pump at a dangerously high rate so neither of these has a pulse and just a side note we never shock anyone with a pause something else to note is that even though ventricular fibrillation and pulseless v-tach meet the criteria for PDA and that there's electrical activity but no pulse we don't typically classify them as peña these two arrhythmias are in a class of their own because we treat them differently their shoppable rhythms peña is considered electric tivity without a pulse that's not v-fib or pulseless v-tach now how do we treat asystole in PA asystole in PA are considered non shockable rhythms meaning providing shock won't likely restore a normal rhythm how do we treat not chocolate um's we start with cardiopulmonary resuscitation or CPR where we alternate chest compressions with some sort of artificial breathing for the patient whether that be mouth-to-mouth or doing oxygen through some sort of mask we'll also administer vasoconstrictive medications now vasoconstrictive means that we're constricting the vases or the vessels so these drugs constrict the blood vessels and equally important with any patient who's pulseless we have to consider any factors that could be reversed that might be contributing to the cardiac arrest and you can remember which factors to consider by the mnemonic h's and teas which we're going to go over in just one second so what are the hsm teas remember they're potentially reversible conditions that could be causing or even contributing to the cardiac arrest so if any patient in cardiac arrest has any of these factors we want to try to reverse it or fix it to help save them now something to know is that a lot of these HS and TS are conditions where there's some sort of lack of adequate blood circulating to the body or adequate oxygen delivery to the body including the heart heart cells need oxygen to function properly so if there's not enough oxygen getting to the heart and the heart cells aren't happy and they quit working properly the first eight we're gonna talk about is hypovolemia so hypo means low and bulimia refers to volume so this basically means low blood volume usually from excessive bleeding and hypovolemia not blood is circulating so not enough oxygen is getting around the next H is hypoxia that means that there's an adequate oxygen supply to the body and hypoxic committee too many things such as drowning or even in a heart attack so there's inadequate oxygen getting to the body to the heart and to the brain the next H is hydrogen ions and hydrogen ions basically means acidosis meaning that the body's pH is too low and acidosis often results from long periods of hypoxia we also need to consider the person's potassium level because hypo and hyper Kaley Mia can lead a cardiac arrest now hypokalemia means that there's too low potassium and hyper Kayle means the potassium levels too high potassium plays a really important role in maintaining normal electrical conduction in the heart so you can imagine that if the levels are too high or too low this will disrupt the heart's electrical conduction system and anyone in cardiac arrest that comes in we're going to check their glucose level because hypoglycemia or low blood glucose can lead to cardiac arrest and this is something that's easily fixed and the last stage we're going to talk about is hypothermia or low body temperature and typically we think of hypothermia is a temperature less than 95 degrees Fahrenheit or 35 degrees Celsius so as a person's core temperature drops the hearts pacemaker cells fire less and less and eventually the heart can stop okay so those are the h's now let's move on to the t's we need to consider toxins and toxins include both prescription medications and street drugs if someone comes in because of cardiac arrest due to a toxin there might be a reversal agent that will help reverse the effects of the toxin and could help save the patient the second T is tamponade and that's something we just talked about and we're referring to cardiac tamponade like we said this is a condition where blood fills a space that lines the heart or the pericardial sac and this constricts the heart makes a lot harder for the heart to pump and sometimes the heart can even pump at all and if the heart's not pumping no blood circulating and one way I like to think about it is to think about doing a jumping jack now imagine that jumping jack underwater it's a lot harder to do a jumping jack underwater because all this pressure is around your arms and legs likewise it's harder for the heart to pump with all the added pressure surrounding it and the next T is something called tension pneumothorax so in the chest wall the lungs are surrounded by a pleural lining so there's a space created called the pleural space between the lungs and the chest wall anna tension pneumothorax air can somehow enter this pleural space and this is usually because of some sort of trauma to the chest and what happens is air enters this pleural space but it can't leave and as more and more air enters a space it crushes the lung and even pushes us along in the heart to the side a crusher collapsed lung is not going to be able to move oxygen very easily in the heart can stop and the last T we're going to talk about is thrombosis basically meaning blood clot and the case of cardiac arrest we're concerned about a blood clot to a coronary artery or an artery that supplies the heart with oxygenated blood or we're conserve a lot in the lungs and that's known as a pulmonary embolism so a pulmonary embolism is a clot in the lung so clots and either the heart or the lungs can lead to severe oxygen depletion and eventually lead to cardiac arrest