This is a little video we did a while ago for the medical students and gives them a practical approach to an arrest scenario. Bad acting aside, it does the job. (As many should notice, the only thing we don’t do first is give the initial 2 breaths).
Basic life support is a key skill for all of us. I mean for ALL of us. In emergency medicine, we resuscitate often and so we almost take it for granted that we know this material. If you are a general practitioner, a healthcare practitioner of any sort, be it surgeon or physician, you need to know this. If you are a nurse, you need to know this. Those of you who are not medical practitioners, but may be dental practitioners or even that subgroup that undertakes sedation of patients, you need to know this!
In medicine, whether you see oncology patients every day, take out gallbladders, or provide family medicine, it is expected of all of us and we must expect it of ourselves, that we know this stuff backwards. We must know the basics of resuscitation.
Just when you were getting it, ILCOR will bring out something new this year. Odds are that the number of compressions to breaths will again increase, highlighting the importance of chest compression and maintenance of coronary perfusion pressure. In fact, I’ll stick my neck out and say that airway will take a minor role in BLS after the new guidelines come out. In fact in BLS, the only thing that makes any difference is chest compressions! In ACLS, and this is not the time to talk about it, the only things that make a difference are defibrillation and cooling. The only other thing that comes out of the latest literature is the benefit of hot coronary angios in patients that have arrested. But more on this in an upcoming issue.
There are two things to remember about arrests. Adults usually have cardiac arrests secondary to ventricular fibrillation or other non-perfusing rhythm. They, in fact, have an arrhythmia and die. In these patients, one of the most important things we can do is defibrillation. If you find them in the first 3-4 minutes, defibrillation is the key. If you find them after 4 minutes, doing a little CPR before defibrillation is important. This has to do with the ‘electrical’ and ‘circulatory’ phases of the heart. More about that on another blog.
In contrast, children usually have arrests secondary to respiratory causes. They usually have an airway issue, become hypoxic and then arrest. There are those of course that have congenital cardiac conditions that may still have a cardiac cause of arrest, however, the predominant cause of arrest in children is respiratory. it is important to work on their breathing first. Open their airway, deliver some breaths, then CPR.
1 There is no real evidence on the best ratio of breathing to chest compressions. There is evidence that maintaining coronary perfusion pressure is advantageous and therefore a minimal interruption to chest compressions is very appropriate. I remember years ago, many a time, when we delayed compressions by searching for that pulse. We couldn’t find it in the wrist or the neck, so someone would check the femoral and they may not be sure, so someone else would then check it. The result would be several minutes of delay. Significant, knowing what we know about how quickly coronary perfusion pressure falls.
With this, the introduction of the new ILCOR guidelines this year are expected to yield even higher compression ratios. Remember that we have progressed from 15:2 to 30:2. It is plausible the the ratio of chest compressions to breaths may increase even further. Is there any evidence for say 50:2? There certainly is no evidence against it. We know that the aortic pressure (used as a surrogate marker for coronary pressures) drops significantly when cardiac compressions are stopped for breathing. This was for the old 15:2.
Watch this space, as I’m sure I’m right about this. So basically, push the chest hard, push it fast and push it deep, and keep pushing it. Sometimes you will feel something crack – keep pushing. After defibrillation, start cardiac compressions right away, don’t stop and take the pulse. If the patient wakes up, they will let you know, believe me! And if I’m right, soon we’ll be told to push more and blow even less.
A little while ago the ‘Spark of Life Conference’ had some T-shirts for sale and they had an area in the centre of the chest that said “push here” and an arrow pointing up to the head and that read “blow here”. It’s really as simple as that.
2 Be careful with your ventilation. Over ventilating a patient is something we are all guilty of. if you are bagging a patient, then you need to be careful not to over-inflate the lungs. Certainly sometimes after we tube the patient, there is a tendency to try and make up for the few minutes we were not ventilating and we furiously pump the bag, getting that oxygen in. I’m guilty of this too.
There is very good evidence that in a resuscitation scenario, more than 10 breaths per minute is associated with ZERO return of spontaneous circulation (Circulation 2004:109;1960-65).
Who has heard of the ‘Lazarus Phenomenon’ (if you’ve been to the Airway Workshop, you’ve heard me talk about this), where a patient we thought deceased, has got an output back? In these cases, the cause is believed to be hyperinflation of the patient’s lungs, increased intrathoracic pressures, thus a decreasing venous return to the heart and a decreasing cardiac output. Stop the bagging, disconnect the tube and the lungs go down, cardiac return starts as does cardiac output and before you know it, BEEP, BEEP BEEP, is what you hear on the monitor.
Ventilation is not only about rate, but also about volume. If an adult bag holds 2500ml and we know that the tidal volume we need to give say an 80kg male is about 800ml or so, then why try to squeeze the ‘heebeegeebees’ out of the self-inflating bag. Try for about half the bag.
So ventilate at appropriate volumes and keep the rate at <10 breaths per minute. A greater rate of ventilation than this, in an arrest, has been associated with no return of spontaneous circulation. Circ 2004:109;1960-1965
3 The depth of compressions worries me. It is true to say and several studies have shown that the rate and depth of compressions suffers with time. Basically at less than about 2 minutes. What is more important is that we don’t recognise that our technique is suffering. It should really be a rule that the person who performs CPR should change over every 2 minutes i.e. every pulse check. This is so important and we may find that given the importance of chest compressions, this is an area that we must all be doing well.
A couple of other things to say. I am very excited about the use of ultrasound in arrests and we use them all the time, especially if we are unsure of cardiac activity. How advantageous it is to be able to see the myocardium and know if it is contracting or not. I invite you all to use the ultrasound machine if you are fighting with a resus and can’t get anywhere. Look at the heart to see if there is cardiac motion. The best view really is not the subxiphoid view that we use as part of the FAST examination, but a parasternal view where we can easily visualise the left ventricle, mitral and aortic valves and the outflow tract. This is not that difficult to learn. More about this in the near future – some videos coming.
The question of when to stop is a difficult one and one that needs a significant discussion. That’s really for another blog. Basically if someone has been in asystole for about 9-10 minutes with no output, you can stop unless they are hypothermic. These patients will not survive. In cases where you have been going at resuscitations for 25 – 30 minutes with no spontaneous return of circulation, again it is time to consider stopping.
What about children that have been found unresponsive i.e. SIDS or children that have arrested in hospital. How long do you resuscitate there? What about if there are staff members that don’t wish to stop a resuscitation. What then? This is a very difficult area and although there are some guidelines, you need to be comfortable with what you wish to do.
Basic life support is just that, basic. For those of us that do this regularly, it’s easy to become a little complacent. It’s easy to say, well the evidence this and the evidence that. The reality is that this is the best evidence we have and we must use it.
In terms of priority, considering the adult population, if you get to them with a defibrillator, shockem if they have a shockable rhythm. If not, chest compressions are the priority, push hard and often (try doing 100/minute for two minutes and see how hard it is). If you can, some airway is good. Stick to the 30:2 for now. Change operators regularly. This is basic, but not easy. Good luck.