Today took b12 inj into vein nurse pulled out some blood frm vein after inseting in vein again she push back blood with b12 is thr risk of air embolis?

No: Body can deal with a small amount of air getting into the circulation. However, B12 does not need to be administered intravenously. If you nor able to absorb B12, intramuscular injection will suffice. For good health - Have a diet rich in fresh vegetables, fruits, whole grains, milk and milk products, nuts, beans, legumes, lentils and small amounts of lean meats. Avoid saturated fats. Exercise at least 150 minutes/week and increase the intensity of exercise gradually. Do not use tobacco, alcohol, weed or street drugs in any form. Practice safe sex.