Question: If we have two lungs and one is seriously damaged, could we survive (without a machine and that kind of stuff)?

Dan Gordon answered on 9 Nov 2016:

Yes. This is not as uncommon as you would think. People may loose a lung through illness (conditions such as pulmonary fibrosis) or through an accident. Under these conditions we would reduce the respiratory capacity by 50%. This would increase the minute ventilation which is the sum of the volume air per breath and the number of breaths. There would also be an increase in the rate at which blood leaves the heart to maintain oxygenation levels, but simply one could survive like this.