Why would patients with COPD be given low flow concentration (1-2l/min) supplemental oxygen?

Low blood oxygen. At the advanced stages of copd, the lungs do not perform their function well, oxygen has a harder time crossing into the blood stream. At this point, the body is not getting enough energy, the blood oxygen level is low. Raising the amount of inhaled oxygen offsets the problem, and prolongs life. Oxygen is used at the lowest amount that would achieve the goal.
All they need... Patients with COPD need to have a certain level of oxygen in their blood to decrease their morbidity and mortality rate. Most patients only need 1-2 liters of oxygen to achieve this level.

Related Questions

For what reason should patients with COPD be given low flow concentration (1-2l/min) supplemental oxygen?

Low oxygen... People with COPD can develop low oxygen levels due to their lung disease. Oxygen therapy is then administered in the lowest amount needed to treat their hypoxia. Too much oxygen can actually cause lung toxicity which worsens lung function.

Why should patients with COPD be given low flow concentration supplemental oxygen?

Helps. If a patient has a saturation less than 88 they qualify for supplemental oxygen. Oxygen is the only therapy proven to prolong life in advanced copd.

For copd, what's considered a high concentration of required supplemental oxygen?

4 - 5 lpm. There is no classification commonly agreed to since it would serve no medical purpose. Most supplier are not able to provide more than 6 lpm without liquid oxygen tanks. People requiring these levels have a very limited life expectancy.
Low flow... Most COPD patients who need oxygen will require 1-2l. It is considered high flow oxygen if greater than 4l is required. Oxygen should only be tittated by your doctor as there is associated toxicity if you are using more than you need.
Depends. 2-3 liters is the usual concentration of oxygen that patients require, anything more than that is a high concentration.