Read the passage below. Use the information in the passage and your own knowledge to answer the questions that follow.
In 2015, a clinical trial in the United States tested a Wearable Artificial Kidney (WAK). This device is a miniature, wearable dialysis machine designed to be worn continuously as a belt around the patient's waist. Before this device was developed, patients with end-stage renal failure had to spend several hours, three times a week, tethered to large, stationary hemodialysis machines in hospitals or clinics. The WAK takes over the primary work of the kidneys: removing excess water, urea, and salts from the blood and returning the cleansed blood to the body.
The device is connected to the patient's vascular system via a catheter inserted into a large vein in the chest. This allows blood to enter the device, pass through the dialyzer membrane, and then return safely to the patient's cardiovascular system.
The pump and filtration systems are powered by rechargeable batteries housed within the belt itself. These batteries must be swapped or recharged every six hours to ensure uninterrupted operation.
A nephrologist conducting the trial wrote that the patient's blood urea nitrogen levels remained stable. Importantly, the continuous filtering meant patients did not suffer from the rapid blood pressure drops often experienced during traditional three-hour high-speed dialysis sessions. Furthermore, because the device is wearable, patients were able to walk, perform light exercise, and go about their daily lives. During light exercise, the clearance rate of metabolic waste can be manually adjusted on the device.
The major advance with the WAK is its portability and continuous operation. Traditional dialysis units are very heavy, loud, and limit the patient's freedom. There is a severe shortage of donor kidneys for transplantation, so a permanent, wearable filtration device represents a potential long-term alternative for many patients who cannot receive a transplant.
Name two waste substances that are removed from the blood by healthy kidneys.
Suggest one reason why the batteries for the Wearable Artificial Kidney (WAK) are placed outside the body rather than inside.
Describe how the blood entering the WAK differs from the blood leaving the WAK.
Explain why a patient might need to increase the clearance rate (filtration speed) of the device during exercise.
Explain why some kidney failure patients are 'not able to receive a transplant'.
Suggest what is meant by the medical term renal.
Suggest two advantages of using the Wearable Artificial Kidney (WAK) compared to traditional stationary hospital dialysis machines.
