[Music] once you start CPR you want to really make it count because patients are much more likely to survive if you perform high-quality CPR than if you perform poor quality CPR and there are five major determinants of CPR quality which we're going to discuss in some detail the first is the rate of compressions 100 to 120 is the rate that every rescuer should be aiming for two is adequate compression depth we want to go about two to two and a half inches or four to five centimeters three is continuity you should be performing CPR for a minimum of 60 percent of your total resuscitation time if not more fourth is chest wall recoil that's diastole in cardiac arrest and that's what allows the heart to refill so we want to make sure that we allow the chest to recoil so the heart can fill normally making each compression count and last is hyperventilation hyper inflating the lungs decreases cardiac output and is another variable that produces adverse outcomes in cardiac arrest so let's start with compression rate there's been a number of studies looking at rate and this is one example in this study they looked at the mean rate of chest compressions among a large sample of cardiac arrest patients and they found that the patients who had compressions at a rate of roughly a hundred to 120 had the highest probability of röszke which stands for return of spontaneous circulation and they also had the highest probability of survival to hospital discharge or having a longer term positive outcome so a hundred to 120 is the rate you want to go for and there's actual science showing us that patients are more likely to survive when we use that rate compression depth we have a similar study looking at depth as an isolated variable again for patients getting return of spontaneous circulation back the optimal compression depth was just under five centimeters and same thing for survival to hospital discharge the optimal compression depth was just a little bit over five centimeters and what they found in general is that any compression death depth over about four centimeters or 38 millimeters produced an odds ratio of 1.9 one of survival to hospital discharge meaning that if you have compressions of greater than 38 millimeters across the board you're twice as likely to survive so it's a really important variable and a really easy one to optimize this graph is about chest compression fraction so in this study they looked at the percentage of time in the overall cardiac arrest that the patient had active chest compressions being performed and they stratified according to the percentage so 0 to 20 20 to 40 40 to 60 etc and they found not surprisingly a linear increase in the likelihood of return of spontaneous circulation as the chest compression fraction increased so if you spend more time during the code performing CPR you're going to get a better outcome and a higher probability of survival this is the same data but this is actually a survival curve rather than the group stratified data and once again chest compression fraction of point eight point nine or 80 to 90 percent of the time produce the highest likelihood of return of spontaneous circulation in another study looking at chest compression fraction the outcomes were a little bit different in this study they found that actually a 60 to 80% chest compression fraction produced the highest odds ratio of survival to hospital discharge and that's what the current guideline recommends so you want to be at a minimum of 60% ideally closer to the 80% range for your chest compression fraction the bottom line though is you're clearly never going to know numerically what your fraction is during the course of a resuscitation you just want to make sure that your CPR is as continuous and uninterrupted as you can possibly make it so chest will recoil is a physiologically important variable but there's actually no human Studies on it that demonstrate improves survival because it's kind of a difficult phenomenon to study but basically the idea is if you lean on the chest in between compressions you're going to increase the patient's inner thoracic pressure right you're smashing down on the chest so that's going to raise the inner thoracic pressure well we all know that positive pressure ventilation also raises the inner thoracic pressure so if you cram more air into the lungs you're gonna raise the thoracic pressure and the bottom line what brings blood back into the heart during diastole it's negative inner thoracic pressure right it's that negative pressure gradient that pulls blood from the periphery back up to the heart so if you raise the inner thoracic pressure and make it not negative you're gonna prevent the heart from filling and you're going to decrease your cardiac output by decreasing your stroke volume the ultimate effect again is going to be impaired cardiac output and that means less blood flow to the heart itself less blood flow to the brain and less likelihood of spontaneous circulation so bottom line high quality CPR is what you need to do to optimize your chances of survival and the determinants once again are push hard four to five centimeters push fast 100 to 120 compressions per minute keep it going you want to make sure your chest compression fraction is a minimum of 60% if not more during the course of the arrest and avoid hyperventilation and chest wall leaning if you do those five things you're going to increase your patients odds of survival so once you have really good quality CPR going what's the next question you need to answer you've already decided your patient is pulseless you've already initiated compressions what do you need to know now the answer is of course what is the cardiac rhythm and specifically is it a rhythm that we can treat with electricity is it a shockable rhythm so shockable rhythms like we said before are more likely to survive patients who can be shocked are more likely to live through a cardiac arrest but defibrillation is a very time sensitive intervention meaning the faster you do it the more likely it is that your patients going to benefit from it so for shockable rhythms we consider to be more important than anything else you can do more important than CPR more important than ventilation more important than drugs or IV access it is the single most important thing that you can do so if you have a shockable rhythm you need to know early and you need to treat it early here's one of our shockable rhythms this is ventricular fibrillation it's very easy to identify it's randomly fluctuating it goes up and down there's no pattern there's no rhyme and reason there's no QRS complexes it's just a disorganized squiggle the second one is ventricular tachycardia now in v-tach there actually is organization to the QRS complexes but they're wide and bizarre-looking so anytime you have a fast rhythm with wide QRS complex complex 'as you should suspect that to be a ventricular tachycardia and by the way these are the two rhythms that the automated defibrillators that you see in public places are looking for when they determine whether or not a patient should be shocked in cardiac arrest so why do we only shock v-fib in v-tach this frustrates a lot of students because you see on TV everybody in cardiac arrest gets shocked and they all jump up and come right back to life right well it doesn't work that way in the real world because the whole goal of using electricity is to reorganize a rhythm that is disorganized now when you are in a non shockable rhythm like peña you have some major problems on the table but electrical disorganization is not one of them it's not an issue for patients and non shockable rhythms and at best if you go and shock an on shockable rhythm nothing will happen at worst you could potentially hit the patient at the wrong point in the cardiac cycle cause an R on T phenomenon and ultimately precipitate a dysrhythmia like ventricular fibrillation so the last thing you want to do in a cardiac arrest is take somebody who has a normal rhythm and turn it into v-fib that's clearly not benefiting anybody so we don't perform too relation for any rhythm except our two shockable rhythms v-fib and v-tach I mentioned before that defibrillation is a time sensitive intervention and this graph clearly shows why so as you can see the more time that elapses as we move along the axis there the lower the likelihood of survival for the patient so for patients and shockable rhythms who are getting shocked within the first minute you can see 3540 percent of those patients are surviving but by the time we get out to 6 minutes it's less than 20% of the patients surviving so we really want to make sure that as soon as we're humanly able to do so we assess the rhythm and we defibrillate if we identify a shockable rhythm again short time to defibrillation high likelihood of survival and as we go down to 2 3 4 5 6 and more than 6 minutes you can see that the odds ratio or the likelihood that the patient is going to survive the event goes down consistently with every minute that passes it's really key to do this quickly all right now once you've gotten your high quality CPR going and you've assessed your rhythm and defibrillated if it's indicated what do you want to do next well this is when you can start thinking about respiratory support for your patient so you can initiate bag valve ventilation in order to give your patients an oxygenation you want to also coordinator chest compressions with your breathing so you're going to do 30 compressions followed by two breaths 30 compressions followed by two breaths you also if you're in a hospital setting are going to establish vascular access and you're going to continue reassessing the rhythm every 5 cycles or 2 minutes for the duration of the resuscitation now a lot of students ask me dr. young this is all great but this is like basic basic stuff right what about the cool stuff like putting in Airways and pushing drugs well unfortunately advanced interventions in cardiac arrests don't really make much of a difference this is a study that came out of Scandinavia that really showed whether you're performing basic life support or advanced life support your outcomes are very similar so in these two cases you can see the red line represents patients who got no IV access no IV drugs and no advanced airway interventions and the green line represents patients that did receive those interventions and you can see how very similar the outcomes for both groups were so bottom line is that CPR and defibrillation is by far the most important element of your resuscitation and all the advanced stuff really doesn't make as much of a difference as we'd like so let's get back to our case so we have our 58 year old guy who collapsed at a sporting event what are we gonna do for him well like we already said one we're gonna call for help as quickly as we can - we're gonna think C a B so we're gonna go to him and we're gonna decide whether or not he's got a carotid pulse if he doesn't we're gonna go ahead and initiate chest compressions and then once we can get access to a defibrillator which hopefully at a sporting event would be pretty quickly we're gonna put it on assess the rhythm and defibrillate if of course it's indicated [Music] you