Patient undergoing spinal decompression surgery. The hand of a patient undergoing surgery, showing IV (intravenous) lines (tubes) and a pulse oximeter attached to the finger. The IV lines are connected to a canula in the patient's wrist, through which various drugs can be administered directly into a vein, including those necessary to anaesthetise the patient. A pulse oximeter attached to the finger measures the patient's pulse rate and the amount of oxygen in their blood. Spinal decompression surgery is an operation to treat pressure put on the spinal cord in this case due to ageing.