Surviving on Mouth-to-Mouth Resuscitation: The Role of Exhaled Oxygen

[Drakkith]

Just wondering if their is a maximum time a person could survive solely on air provided by another person giving them mouth-to-mouth. I've read a little on the subject, and it seems like there is enough oxygen left in a person's exhalations to keep someone alive for as long as mouth-to-mouth is required, but I just wanted to make sure.

Wiki says there is about 17% oxygen content in an exhaled breath since the the body only uses about 4 of the 21% oxygen in the air.

 

[AlephZero]

Wiki says there is about 17% oxygen content in an exhaled breath since the the body only uses about 4 of the 21% oxygen in the air.

Under what conditions? For "normal" breathing, your breathing rate adjusts to match your oxygen demand. AFAK the amount of CO2 in the exhaled air is one of the "signals" which controls the rate.

But mouth-to-mouth resuscitation isn't normal breathing - you are using your lungs as an air pump.

 

[berkeman]

The problem isn't so much with the slightly reduced O2 that you are giving the patient, the problem is with the extra CO2 that you are breathing into them. The extra CO2 leads to acidosis in the blood, which is not good for the body. The sooner that you can start ventilating them with O2 rather than your exhaled breaths, the better.

http://www.nlm.nih.gov/medlineplus/ency/article/000092.htm

With O2 and good ventillations and compressions, folks have survived in the 40's of minutes, but it's rare:

http://www.procprblog.com/56-year-old-man-is-alive-after-47-minutes-of-cpr-with-aed

 

[Manish7]

mouth to mouth resuscitation means for continual of breathing although dec. breathing leads to respiratory acidosis
therefore amount of O2 in the other person continues breathing.
it advantages for only small interval of time until emergency services arrive !

 

[atyy]

The problem isn't so much with the slightly reduced O2 that you are giving the patient, the problem is with the extra CO2 that you are breathing into them. The extra CO2 leads to acidosis in the blood, which is not good for the body. The sooner that you can start ventilating them with O2 rather than your exhaled breaths, the better.

http://www.nlm.nih.gov/medlineplus/ency/article/000092.htm

With O2 and good ventillations and compressions, folks have survived in the 40's of minutes, but it's rare:

http://www.procprblog.com/56-year-old-man-is-alive-after-47-minutes-of-cpr-with-aed

I wonder how long before acidosis is a concern. Let's say the heart is fine, and only breathing stops (say pentobarbital overdose) and one catches it exactly when breathing stops, so one only has to give artificial respiration until the drug wears off a bit (say 1 hour). Would acidosis be a concern over such a short period of time?

 

[Manish7]

acidosis will increase respiration so the breathing might continue but the disadvantage is that acidosis
depress CNS activity which may lead to coma and certain death.

 

[Drakkith]

acidosis will increase respiration so the breathing might continue but the disadvantage is that acidosis
depress CNS activity which may lead to coma and certain death.

What do you mean the breathing might continue?

 

[Manish7]

i was taking a case of acidosis not talking about mouth to mouth resuscitation.