dumb cpr question

most recent AHA guidelines recommend 30:2 for healthcare providers, stop compressions for breaths, watch chest rise and fall, etc...start compressions again...of course it doesn't go that smoothly on a real arrest in the field! ha!
 
It's not that confusing. St. John Ambulance taught you the universal 30:2 because they taught you the lay rescuer guidelines.

If they taught you the HCP guidelines it would be 30:2 for single rescuer (adults, children, infants) and 15:2 for two rescuer children and infants only. This will be the same whether you go to the Heart and Stroke Foundation, Red Cross, or St. John as long as they are following the guidelines.

With two rescuers I think they like to see the children and infants getting more oxygen. It is still 30:2 for adult two rescuer.
 
New "dumb" question- How does capillary gas exchange occur if you have to stop compressions for rescue breaths? I'd imagine very little O2 gets into the blood from those 2 breaths, considering the heart isn't "beating" to carry away the oxygen-saturated blood and bring in more CO2 saturated blood.

Make sense? (please say yes) :)
 
I don't know a whole lot about the cardiovascular or pulmonary systems, but it would seem to me that when giving respirations, you would only be able to load up the hemoglobin present in the capilaries of the lungs at that moment with O2 since blood is not flowing. However, you are also leaving air with about 16% O2 in it in the dead space of the lungs, and while compressions are being done, gas exchange to some extent can still occur, now that you do have bloodflow.

So, gas exchange would still occur, but at a very reduced capacity.
 
Also remember that when you exhale or BVM all of the air in your lungs doesn't go out. There is still some in there, that should be able to provide some exchange, so I am sure that helps as well.
 
Also remember that when you exhale or BVM all of the air in your lungs doesn't go out. There is still some in there, that should be able to provide some exchange, so I am sure that helps as well.

Yup, that be the dead space I mentioned.
 
30 to 2 for everyone single rescuer - 15 to 2 double rescuer infants and kids. ALWAYS stop compressions then two breaths...rinse reuse repeat..lol. only continue compressions and ventalations with a et tube in place when directs by a medic it usually ends up being like 6 compressions per one breath. just watch the lifepack monitor to keep up the respiration rate.
 
New "dumb" question- How does capillary gas exchange occur if you have to stop compressions for rescue breaths? I'd imagine very little O2 gets into the blood from those 2 breaths, considering the heart isn't "beating" to carry away the oxygen-saturated blood and bring in more CO2 saturated blood.

Make sense? (please say yes) :)


Not a dumb question, it's actually very intuitive. The whole reason AHA came up with these guidelines to do more compressions, and are actually looking at continuous compressions without breaths, is because the gas exchange is only occurring with the circulation of blood throughout the capillary membrane of the alveoli. If there is no blood circulating then you have no exchange, or very minimal exchange. Therefore, compressions are key to eliminating CO2 from the blood, and delivering O2 back to the organs. However, it is known that compressions during CPR are only delivering 25% of the compression strength and contractility that the heart is delivering on it's own (in a normal state). So, that explains why we have to worry about lack of gas exchange and the body ultimately ending up in a hypercarbic state, which is why we have to give sodium bicarb to our codes.
 
New "dumb" question- How does capillary gas exchange occur if you have to stop compressions for rescue breaths? I'd imagine very little O2 gets into the blood from those 2 breaths, considering the heart isn't "beating" to carry away the oxygen-saturated blood and bring in more CO2 saturated blood.

Make sense? (please say yes) :)

Simple. Diffusion occurs continuously as long as a concentration gradient is present. The concentration gradient is refreshed when ventilated and doesn't go away the second a breath is exhaled.

Now, it's important to understand about the different types of lung volume.

spirometry_diagram1.gif


Now, if you just relax and exhale you would have about 2.5 liters of air in your lungs. That is comprised of two separate sets of "volume." Now, in your relaxed state, try to exhale ALL of your air. This is the expiratory reserve volume. Even besides that, there is still some residual volume that you can't exhale. Even if you can't exhale it, it still gets mixed, to an extent, when you breath. That's why you don't have to ventilate continuously.
 
2boss4:

You stop compressions when there is no advanced airway in place. (ex. BVM with NPA or OPA) You do not stop compressions once the pt has an advanced airway in. (ex. ET tube or Combitube) Once there is an advanced airway in place, you do continuious compressions only stopping for rythym checks ;)

Take Care,
 
Last edited by a moderator:
The vacuum

The only time what your saying is true, as some others have stated, is if an advanced airway is in place and secured.

The physiology is simplier then one might think really. Technically, if yo have an advanced airway in place, the chest will inhale and exhale with compressions, and the breaths are only suplimental to this effect. When a chest compression is performed, and if it is performed correctly, it will compress the intrathoracic muscles as well as the heart. This will cause the lungs to push out the air, and the diaphram to move in the downward direction. When the compression is released, the muscles in the chest, which are connected to the lungs via the parietal and viceral masses, will cause the lungs to reopen, which will cause the air pressure in the lungs to create a negative pressure, which will cause air to enter the lungs. Its alot like the effect of bulb syringe; when you squeeze it, it pushes out the air, and as it reexpands, it will suck air into it. Once the air enters the alveoli, diffusion does the rest, and the compressions that you are giving causes the heart to circulate the now freshly oxygenated blood.

Does this help you any?
 
Back
Top