understanding how a cardiac arrest leads to respiratory arrest

catshowlady · May 7, 2009

I work ICU. Basically, once the heart goes, the pt becomes unconscious. That means they can no longer protect their airway and they quit breathing, which buys them an ET tube. Anybody who arrests, unless they come back immediately, ends up intubated. In addition, BVM ventilation is to be done with relationship to chest compressions during CPR, whereas once the pt is intubated, you can ventilate without interrupting chest compressions.

Plus, some of the reasons for a code include things that can be fixed/helped by mechanical ventilation, especially hypoxia and hydrogen ion imbalances.

HTH.

:paw:

thinkertdm · May 7, 2009

Maybe something like this- the heart can no longer adequately pump enough blood to keep tissue (including the diaphragm and intercostal muscles) oxygenated and producing ATP. Since those muscles now have no source of energy (which should be coming from the heart), they have to switch to an anaerobic souce of energy, which can't keep up with the metabolic demand of those muscles, and since no more oxygen is getting in the system, you have a double whammy (no blood circulation and a rapidly diminishing source of oxygen). On top of that, you now have huge amounts of CO2 being produced, lactic acid is building up...

How does that sound?

pagandeva2000, LPN · May 7, 2009

Both explanations sound like winners to me! ~

silas2642 · May 7, 2009

Basically what you need to know is that there are two hearts-- the right heart, which pumps deoxygenated blood to the lungs to get oxygenated, and then the left heart which pumps oxygenated blood to the rest of the body. In cardiac arrest, the pump doesn't work and blood doesn't flow at all-- it just sits there.

Remember that the brain does not do well at all without oxygen, and the brainstem (medulla) is what is responsible for your breathing-- within minutes brain cells start to die. So you can imagine that if your heart isn't pumping blood, and your brain isn't working because it isn't receiving oxygen from your heart farting out how this could lead to your lungs failing since your breathing depends on your brain.

thinkertdm · May 7, 2009

Basically what you need to know is that there are two hearts-- the right heart, which pumps deoxygenated blood to the lungs to get oxygenated, and then the left heart which pumps oxygenated blood to the rest of the body. In cardiac arrest, the pump doesn't work and blood doesn't flow at all-- it just sits there.
Remember that the brain does not do well at all without oxygen, and the brainstem (medulla) is what is responsible for your breathing-- within minutes brain cells start to die. So you can imagine that if your heart isn't pumping blood, and your brain isn't working because it isn't receiving oxygen from your heart farting out how this could lead to your lungs failing since your breathing depends on your brain.

This is true, and brain damage is very important to consider with any episode of hypoxia/anoxia, and both probably happen within seconds/minutes of each other.

However, consider this- if the brain is so damaged that it cannot maintain breathing, then your chances of recovery are slim (as the brain is damaged). However, as catshowlady points out, you can have a successful recovery by mechanical ventilation.

I would suppose that muscle exhaustion occurs first, followed shortly by brain damage, and then death.

jjjoy, LPN · May 7, 2009

Great discussion!

drew9319 · May 8, 2009

keep this in mind as well. when the heart stops. we only have a 5% chance of recovering a pt. if the cod ehappens outside the hospital. it doesnt increase that much inside the hospital from the outside. when the heart fails and the o2 in the blood runs out. thats when the brain starts to die, as well as the heart. research has show that we can reduce the incidence of anoxic brain injury by inducing hypothermia. here is the link. http://content.nejm.org/cgi/content/short/346/8/549

hope this can help increse the knowledge we are sharing great thread

gt4everpn, BSN, RN · May 8, 2009

Cardiac arrest= no blood supply to medulla region in brain which controls breathing which can lead to respiratory arrest due to starvation of oxygen to medulla, as well as lung cells.

nursgirl · May 8, 2009

I am a student also... what is the best way to induce hypothermia? I feel stupid for asking... but I've never seen it done.. are we talking ice? Is there some med that is used? Thanks in advance!!!!!

Btw, thanks for the above info too...

catshowlady · May 8, 2009

I don't know the best way, as we don't use this protocol (yet). I believe iced saline infusions are one thing that can be used to induce hypothermia, followed by a cooling blanket. You could also use ice bags in a pinch, I suppose.

I'm sure my facility would use a cooling blanket, as we already have these to use to control fevers.

drew9319 · May 9, 2009

we use the artic sun blanket here to induce hypothermia. but you can do it with iced saline and ice packs. that is only in an emergency though(ie malignant hyperthermia) the reson you really should use a cooling blanket is because you want to control the rate of cooling.