5 ms·
No, it detects the release of CO_2 from the blood to the pulmonary alveoli. Presence of CO_2 in the alveoli signs the presence of a blood flow, regardless of t
by pygy_ 15y ago
No, it detects the release of CO_2 from the blood to the pulmonary alveoli.
Presence of CO_2 in the alveoli signs the presence of a blood flow, regardless of the nature of the pump (heart vs CPR).
If the blood flows, the organs (including the brain, which is the most sensitive to oxygen deprivation) are properly fed and viable (assuming CPR started soon enough).
- sp332 15y agoWell, the heart still has to be in more-or-less the right "shape", right? If the valves are messed up, blood won't circulate through the lungs and back to the organs properly. http://en.wikipedia.org/wiki/File:Heart_diagram_blood_flow_en.svg http://en.wikipedia.org/wiki/File:Heart_diagram_blood_flow_e...
- pygy_ 15y agoIndeed, the valves must be in working order, and there must be enough blood in the vessels to close the circuit and prime the pump. I don't know if it was confirmed, but while I was a student, there were strong suspicions that blood in the whole thorax (pulmonary circulation), not only in the heart, contributed to the assisted flow. Another fun fact: CPR is more efficient if you use a plunger to perform the chest compressions, because you can push and pull it, thus not only pumping blood out of the heart (through the arteries), but also actively sucking it back in (from the veins). As a consequence, at the end of a cycle, there is more blood in the chest to be pumped out on the next one. See http://www.ncbi.nlm.nih.gov/pubmed/21251705 http://www.ncbi.nlm.nih.gov/pubmed/21251705 for the details.