CPR is increasingly a HS graduation requirement in US and UK systems. CPR can easily be covered in the #physics curriculum since the heart is basically an electrochemically driven mechanical pump. #iteachphysics
CPR is increasingly a HS graduation requirement in US and UK systems. CPR can easily be covered in the #physics curriculum since the heart is basically an electrochemically driven mechanical pump. #iteachphysics
We can apply circuity theory, thermodynamics, solid and fluid mechancs to explain cardiac dynamics, and make the physics class the place to fulfill the CPR graduation requirement #iteachphysics
We can apply circuity theory, thermodynamics, solid and fluid mechancs to explain cardiac dynamics, and make the physics class the place to fulfill the CPR graduation requirement #iteachphysics
Today we have special participant this week, @MedCrisis, a Cambridge-trained cardiologist doing a PhD @UCL. Science & medical educator that makes movies, graphics and bad jokes. #SciComm dilettante. #iteachphysics
Today we have special participant this week, @MedCrisis, a Cambridge-trained cardiologist doing a PhD @UCL. Science & medical educator that makes movies, graphics and bad jokes. #SciComm dilettante. #iteachphysics
But before we get started let's do an #iteachphysics roll-call. Where do you teach #physics? What level of students? Is CPR a graduation requirement where you are? If so, who is responsible for doing the training.
But before we get started let's do an #iteachphysics roll-call. Where do you teach #physics? What level of students? Is CPR a graduation requirement where you are? If so, who is responsible for doing the training.
But before we get started let's do an #iteachphysics roll-call. Where do you teach #physics? What level of students? Is CPR a graduation requirement where you are? If so, who is responsible for doing the training.
Please remember to include #iteachphysics in all your tweets.
Teaching #physics of CPR is to teach a critical llife skill. It's another example of #physics for civil society, and a way to make the #physics teaching staff indispensable in the schoolhouse. #iteachphysics
Teaching #physics of CPR is to teach a critical llife skill. It's another example of #physics for civil society, and a way to make the #physics teaching staff indispensable in the schoolhouse. #iteachphysics
Hello! Happy to be here, thanks for inviting me along. As you said the heart is a combination of an electrical circuit which produces mechanical forces via muscle contraction. Here is the isolated electrical system of the heart #iteachphysics
The sinoatrial node is referred to as the intrinsic pacemaker of the heart, it is collection of specialised cell that spontaneously depolarise and initiate an impulse that travels along the conduction system in a coordinated manner - this is called sinus rhythm #iteachphysics
This produces contraction of the atria (top chambers) & then ventricles (bottom chambers). The heart can be thought of as a double pump - the right heart receives blood from the body & pumps to the lungs, the left heart receives blood from the lungs & pumps to body #iteachphysics
Ah well you've helpfully provided a diagram explaining the sounds - the bottom line in the figure above. There are normally 2 heart sounds - the closure of the mitral and tricuspid valves (1st sound) and closure of aortic and pulmonary valves (2nd sound). But > #iteachphysics
> there are many abnormal variations. The sounds may be split, quiet, absent, unusual or there might be extra sounds like murmurs which represent turbulent non-linear flow, rubs, clicks etc etc. This is what the doctor listens for. Nowadays ultrasound is often used #iteachphysics
Great question. When talking about CPR, this is given after cardiac arrest - the heart has stopped pumping properly. A heart attack is a blockage in an artery supplying the heart. About 2% of heart attacks cause cardiac arrest, but CA can occur without heart attack #iteachphysics
Speaking of sounds and the heart, two of my @InterlochenArts students, and arts colleague of mine, and I conducted a cool experiment at the local cardiology department. The experiment led to a live #arts performance that was fantastic. Details shall follow. #iteachphysics
In reply to
@MedCrisis, @iteachphysics, @InterlochenArts
#iteachphysics Q4: Lets' get to the specifics of CPR. The obvious purpose of CPR is keep some level of hemodynamic and oxygen delivery to the body. @MedCrisis What are the best techniques for 1-person and a 2-person team?
I would urge people to look it up properly with their resuscitation authority eg @American_Heart@ResusCouncilUK but in essence there are a few key priorities - get help 1st. If alone guidelines have changed in recent yrs to emphasise hands-only CPR, no breaths #iteachphysics
In reply to
@BlackPhysicists, @American_Heart, @ResusCouncilUK
If there are 2 people, you can still stick to hands-only CPR & use each other to ensure no one gets tired & compression quality remains good. However if both are trained, one can then perform rescue breaths. Priority is minimising time without compressions #iteachphysics
In reply to
@BlackPhysicists, @American_Heart, @ResusCouncilUK
The reason being is shown in this schematic - haemodynamic pressure is not generated immediately and takes time to establish, but disappears quickly when CPR stops #iteachphysics
In reply to
@BlackPhysicists, @American_Heart, @ResusCouncilUK
Yes. I read somewhere that people's apprehension with mouth-to-mouth was an impediment to offering CPR help. But it can done w/o breaths, which is much, much better than nothing #iteachphysics
In reply to
@MedCrisis, @American_Heart, @ResusCouncilUK
Only in #iteachphysics chats you get to learn about a variety of things including important #medical matters. Join in for an informative session that fuses #Physics and #Health!
#iteachphysics Q4: Lets' get to the specifics of CPR. The obvious purpose of CPR is keep some level of hemodynamic and oxygen delivery to the body. @MedCrisis What are the best techniques for 1-person and a 2-person team?
Right - I think many people don't realise how much compression is required, perhaps because TV shows & films show it being performed on actors! If done properly to a conscious person it would be painful - about 2-3"/5cm compression is needed in most cases #iteachphysics
The physics of compressions are that positive pressure on the chest (downward force) displaces blood in the heart outwards, hopefully towards the brain (but only a small amount gets there). As you release, the chest re-expands & negative pressure pulls blood in #iteachphysics
There is a somewhat famous force v depth curve for Guidline Compliant Compressions, from which you can calculate work. With compression rate then power, then integrate over time. https://t.co/lACpCHTCZd#iteachphysics
Anyone can use an AED - they are simple & give clear instructions. As soon as cardiac arrest is diagnosed, call for help, start compressions & get someone else to get an AED. Stick it on without stopping compressions. It works like this > #iteachphysics
In some types of CA (not all) the coordinated sinus rhythm we mentioned earlier is replaced by a chaotic, ineffective electrical pattern. These respond to extrinsic electrical energy to 'reset' the heart cell (myocyte) depolarisation cycle. This is defibrillation #iteachphysics
This makes me wonder. If one treats the heart as a spring, what would its spring constant be? What would the average ∆x for a healthy heart would be? And while it is beating, what is the average force a human heart is subject to? Or, energy route is better? #iteachphysics
The spring in this scenario is the rib cage - the chest's recoil determines how much negative pressure is generated. Unfortunately most cardiac arrests happen in older people and instead of bouncing back, often CPR results in multiple cracked ribs & poor recoil #iteachphysics
Work w other person to apply AED. Synchronize compression & AED deployment to minimize pauses, discharge on upstroke #iteachphysics
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Defibrillation delivered during the upstroke phase of manual chest compression improves shock success https://t.co/hTtJwVF8gb
#iteachphysics Q6: @MedLife What kind of blood and O2 flow rates can be delivered via CPR compared to the normally functioning cardio-pulmonary system?
#iteachphysics Q6: @MedLife What kind of blood and O2 flow rates can be delivered via CPR compared to the normally functioning cardio-pulmonary system?
Ouch! But, this would be equivalent to a spring loosing its springiness (expanded too much or contracted too much), correct? i.e. Hooke’s law is no longer applicable. Are you aware of any measurements of Young modulus for ribs? #iteachphysics the #Coolism way, via the #arts! :-)
#iteachphysics Q7: @MedLife What are some physical measurements that could be made to see of CPR is working. Are there factors that lead to more mechano-electrically coupling, i.e., restarting/resetting the electrical system?
You're tagging someone else there - @medlife not @medcrisis!
The key objective is blood flow to brain and heart - especially brain. But even with good compressions <25% of normal blood flow to the brain is achieved. #iteachphysics
In reply to
@BlackPhysicists, @medlife, @medlife, @MedCrisis
EMD - electromechanical dissociation is a hallmark of cardiac arrest, electrical activity and mechanical activity are considered & assessed separately. ECG determines the former & usually detecting a pulse or blood pressure measures the latter #iteachphysics
True story... A guy went into cardiac arrest at my wedding reception ~30 yrs ago. I think we broke a rib b4 fire dept came. It was the first time I saw a Lucas unit. #iteachphysics
Our varsity vball squad lost a tough match this morning. The other coach mentioned how we played "less than the sum of our parts" and for the rest of the conversation all I could think about was binding energy and mass defect. #iteachphysics
End-tidal CO2 monitoring is a technique measuring carbon dioxide from a breathing tube (ie the patient has had a tube placed in their windpipe) that is well correlated against cardiac output. So it is an indirect measure of CPR efficacy #iteachphysics
#iteachphysics A8: This is all unchartered territory for me; I will have to digest the information from today’s chat and then proceed with some cool curricular implementations.
#iteachphysics Q9: @MedCrisis On TV we often see a person giving a stricken patient a thump to the chest. Can you discuss the mechanical-electrical feedback that that technique is trying to achieve?
Wow 30 years ago?! The Lucas is one of I think 3 automated CPR machines on the market. They are brutal but effective. They don't get tired unlike humans, so compression quality maintained but so far scant evidence to show they improve survival (but are useful) #iteachphysics
This is a great gif but a bit too fast & a lot going on - however once you get to know the cardiac cycle it's a really satisfying marriage of electrical activity, biomechanics and fluid dynamics #iteachphysics
First thing to say is this is not taught for out of hospital cardiac arrest. In fact it's very rarely done IN hospital as there are usually better techniques. To an onlooker it just appears as though you're hitting a dead person! The idea is simple though #iteachphysics
#iteachphysics Q10: @MedCrisis You recently rode the London tubes with a cow's heart in your cartage. I presume you were doing a demo somewhere. How did that day go for you? What can physics students learn from bovine cardiology?
It is a poor man's defibrillation. It is supposed to deliver ~5J of energy. It is not very effective compared to electrical defib and it is entirely ineffective for non-shockable rhythms. You don't know what rhythm someone is in without a monitor - don't guess! #iteachphysics
