So, at the end of the day, your answer is "spirit = life force = breathing". It's just a metaphor for breathing. So when you write:
"If it's lungs are underdeveloped they can't handle spirit or force of life effectively assistance would therefore be required for the baby to benefit from the force of life spirit oxygen to allow it a chance of survival.", we can rephrase that as "If it's lungs are underdeveloped they can't handle breathing or force of breathing effectively assistance would therefore be required for the baby to benefit from breathing oxygen to allow it a chance of survival."