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Thousands of people every day in the United States have heart surgery. In 2006 (the most recent year for which the American Heart Association has data), surgeons did nearly 448,000 coronary bypass surgeries. Even though there is a shortage of donor organs, over 2,000 people had heart transplants.
Because the heart is constantly beating, heart surgery has challenges that no other type of surgery has. Not only does it move, it cannot be stopped for more than a few minutes without causing brain damage.
Two major medical advances have made heart surgery possible:
- The heart-lung machine, which takes over the work of the heart during surgery
- Body cooling techniques, which allow more time for surgery without causing brain damage
The Heart-Lung Machine
This machine is also called a cardiopulmonary bypass machine. It pumps blood while your heart is stopped and adds oxygen to the blood before it is pumped throughout the body.
During surgery a perfusion technologist or blood-flow specialist operates the machine, monitoring the flow of the blood during surgery to make sure that the heart-lung machine is doing its work properly.
Before you are hooked up to the machine, a blood-thinning drug (an anticoagulant) will be given to you to prevent your blood from clotting in the machine. The heart-lung machine works like your heart:
- It carries blood from the heart's upper right chamber (right atrium) to a special reservoir.
- The reservoir, called an oxygenator, bubbles oxygen through the blood. The red blood cells pick up the oxygen, changing from dark to bright red.
A filter removes the air bubbles from the oxygen-rich blood.
- The blood is returned to the body's main blood vessel, the aorta, through a plastic tube.
- From the aorta, the blood moves through the rest of the body back into the heart-lung machine.
By cooling the heart, its need for oxygen is reduced. This allows surgeons to work on the heart for two to four hours without damaging the heart tissue. There are two ways to cool the heart:
- Cooling the blood as it passes through the heart-lung machine, which causes the body temperature to go down as the blood moves through the body
- Pouring cold salt water (saline) over the heart
Not all heart surgeries done today require the heart-lung machine or extreme cooling.
Throughout the preparations for surgery and the surgery itself you will be monitored using an electrocardiogram. You may be given blood tests, urine tests and a chest X-ray to give your surgeon the latest status of your heart and health.
After you are completely asleep, a tube will be inserted down your windpipe and connected to a machine called a respirator, which will take over your breathing. A second tube will be inserted through your mouth, down your throat and into your stomach. This stops liquid and air from collecting in your stomach, so you will not feel sick and bloated when you wake up. A thin tube called a catheter will be inserted into your bladder to collect any urine produced during the operation.
An intravenous (IV) line (a needle with a tube connected to it) will be put into a vein. This will be used to give you anesthesia before and during the operation. A special line will be put into a artery to monitor your blood pressure and to draw blood samples.