Your father probably has chronic obstructive pulmonary disease. A difficulty in the oxygen being delivered from the lungs to the red blood cells in his blood. Thus the hemoglobin in his red blood cells are not all filled with oxygen. Hemoglobin, if unfilled with oxygen, changes from a red color to a deep blue/purple color. That is why we think of blood coming from the heart as red and returning to the heart as blue on diagrams of the circulatory system. In fact, if your father was not on oxygen, his nails probably would be an even darker blue color. The oxygen should be, in fact, improving his color.
Gasping for breath, blue around the mouth, blue fingerts and under the nails, cold hands and feet and diziness
Blue nail polish or certain types of dyes in fabric or hair color can transfer onto the nail plate, resulting in a blue tint. It is important to use a base coat before applying colored nail polish to help prevent staining. Additionally, ensuring nails are clean and dry before applying any pigmented products can help reduce the risk of discoloration.
Dark nails indicate a B12 deficiency, white nails can indicate anemia, red nails are due to heart disease, blue nail beds are a sign of a lack of oxygen in the blood, and yellow nail beds are a symptom of liver disorders. There are also other things your nails can indicate by the ridge type, the shape of the nail, and the quality of nail (brittle or fraying for example) as well.
liquid oxygen is blue
Your left foot turning blue would be caused by cyanosis. This is when the blood does not get enough oxygen in it. You should immediately contact a doctor regarding this.
Blue
light blue nails
So they can monitor the color under your nails. If it turns blue, for example, you need oxygen, and it's important for the Dr's, to know that.
No, oxygen is colorless
you should paint them blue
June 30th
The blue color in snail mucus is due to a protein called hemocyanin, which contains copper and gives it a blue hue. When exposed to air, hemocyanin reacts with oxygen and changes its structure, resulting in a blue color.