If you or a loved one has been diagnosed with coronary atherosclerosis, it means there's cholesterol build-up as well as injury and inflammation in the inner wall of the heart’s arteries. 

Lifestyle changes, medical therapies and stents to open up obstructions in the arteries can work for years and even decades. When they fail, a heart bypass surgery, which reroutes blood flow around the blocked area, may be needed.

Patients who visit the Yale Medicine Cardiac Anesthesiology Program often have significant blockage and failing health. The medical management—not just for the heart but for all the organs—becomes the responsibility of the anesthesiologist.

Heart bypass surgery can take from three to six hours and requires general anesthesia. During that time, you may be attached to a bypass machine, which does the work of the heart and the lungs while the surgeon is working and the heart is arrested (not beating).

Anesthesiologist have two different roles during the surgery. The first is administering the anesthesia to keep you asleep, numb pain and prevent movement.

The anesthesiologist also has the crucial role of monitoring your overall health before, during and after the surgery. That means monitoring blood pressure and performance of the heart and all other organs (brain, lungs, kidneys, liver) and anticipating and skillfully dealing with such challenges as resuscitation during the operation or bleeding major enough to require transfusion.

These responsibilities continue until the patient is safely transferred to the intensive care team after the surgery ends. 

Before heart bypass surgery, surgeons and anesthesiologists gather information about a patient’s arterial blockages, noting which vessels are diseased, for example, and how severely. In addition, the anesthesiologist will want to know about all underlying health problems, including ventricular dysfunction, diabetes or kidney problems. 

When a patient has been prepared for heart bypass surgery, doctors place standard monitors (including an electrocardiogram, or EKG) followed by an arterial line, which monitors blood pressure continuously.

Not long after that, the anesthesiologist puts you asleep with intravenous sedation drugs. That’s the last thing you should feel until waking up in the intensive care unit or sometimes a special cardiothoracic ICU. You stay under general anesthesia (fully asleep) during the duration of the surgery.

You will be maintained under general anesthesia while the success of the surgery is monitored, making sure the bypass is allowing blood to reach the heart.

When you wake up in the ICU, you will still be hooked up to several monitors, including a mechanical ventilator to help with breathing. After several hours if stable, you will begin weaning from the artificial breathing to spontaneous (normal) breathing without support.

Doctors set up several monitors to oversee a patient’s well being during heart bypass surgery. The first step is to set up an arterial line, which allows the anesthesiologist to observe blood pressure while the surgeon is operating on the heart.

Once a patient goes to sleep, anesthesiologists insert other monitors. One is a catheter that goes into the heart and checks its function and pressures within several of its chambers. Another is an ultrasound probe that goes in through the mouth to the esophagus or stomach.

This is called a transesophageal echocardiography (TEE), and it enables doctors to see a clear picture of the heart and nearby structures. Using all of these monitors, anesthesiologists chart a patient’s blood pressure, blood oxygenation, levels of carbon dioxide and heart rate and alter medical management as needed.

The anesthesiologist is also responsible for assessing the success of the bypass. The TEE, in particular, can help the anesthesiologist tell whether the heart is functioning properly, or whether there are remaining adjustments needed, even after the bypass.

Once the anesthesiologist and the surgeon confirm that the surgery is a success, the team can wind down the operation.

In general, the incidence of death under anesthesia is low. But because cardiac surgery is very complex, and the patients who come in are not in peak health, there is some risk.

Side effects to anesthesia include a few reactions to narcotics, such as nausea and vomiting. Combined with surgery, the drugs can also result in shivering and some mental confusion. All of these problems generally clear up for patients very quickly. 

There are also separate overall surgical risks such as bleeding and infection.

Yale Medicine doctors and researchers are always innovating, testing and adapting new procedures. That means that patients can expect to be treated by cardiologists and surgeons who are experts in the newest technologies.