Answer:
Total knee replacement is a medical surgery that helps in removing the defective knee and replaced the knee with the synthetic material. Any defects in the knee can be corrected by this surgery.
Autologous transfusion is the type of blood transfusion in which the blood is taken from the another part of the patient's body and then reinsert in the same body. The total knee replacement might require autologous tranfusion. The statement made by the nurse that she needs to donate blood around 4 to 6 weeks before the surgery indicates autologous transfusion.
During an asthma attack the muscle wall contracts and the lining of the airways becomes swollen and inflamed. These changes cause a narrowing of the airways which is further aggravated by an increase in secretions from the mucus membrane, which may actually block the smaller airways hope this helps