Anesthesia in Cardiac Surgery

One of the questions patients facing heart surgery ask most often is: "If my heart is going to be stopped, how will I stay alive?"

The question is entirely natural. Cardiac surgery occupies a different place in people's minds from other operations.

It is indeed one of the most advanced areas of anesthesiology. Thanks to the technologies used in modern cardiac surgery and cardiac anesthesia, however, very complex operations can now be performed safely.

Why is anesthesia different in cardiac surgery?

In no operation is the job of anesthesia simply to send the patient to sleep. In cardiac surgery the task is far broader.

The anesthesia team does not only control consciousness, prevent pain and manage breathing. It also continuously follows:

• The performance of the heart
• The circulation of blood
• Blood flow to the brain
• Kidney function
• Oxygenation of the other organs

Anesthesia in cardiac surgery is, in a sense, the simultaneous management of every system in the body.

Is the heart really stopped?

In some cardiac operations, yes.

In coronary bypass and certain valve operations in particular, the heart may need to be stopped temporarily so that the surgeon can work safely.

This can sound alarming. But the body's circulation does not stop.

How does circulation continue?

This is where the heart-lung machine comes in. Known medically as cardiopulmonary bypass, it can temporarily take over the work of the heart and lungs during surgery.

The system:

• Draws blood from the body
• Oxygenates it
• Removes carbon dioxide
• Returns the blood to the body

The brain and other organs therefore continue to receive blood while the surgeon works on the heart.

What does the anesthesiologist do?

Most people know that the surgeon is working throughout the operation. In cardiac surgery the anesthesia team's role is just as active.

Throughout the operation the following are monitored moment by moment:

• Blood pressure
• Cardiac output
• Heart rhythm
• Oxygenation
• Blood gases
• Body temperature
• Blood loss

Some decisions may have to be made within seconds. Cardiac anesthesia is one of the areas of anesthesiology that demands the highest level of monitoring and coordination.

Which monitors are used?

Standard monitoring is often not enough in cardiac surgery, so additional methods may be used, among them:

• Arterial blood pressure monitoring
• Central venous pressure monitoring
• Advanced haemodynamic monitoring
• Transoesophageal echocardiography (TEE)

TEE in particular allows images of the heart to be assessed directly during the operation.

What is transoesophageal echocardiography?

TEE uses a special ultrasound probe placed in the oesophagus to image the heart from the inside. It is an extremely important tool in cardiac anesthesia.

It allows the following to be assessed during surgery:

• The heart valves
• The strength of contraction
• Blood flow
• The success of the surgical repair

Is anesthesia riskier in cardiac surgery?

Cardiac operations are inherently major surgery and require more extensive preparation than many others.

Today, however, success rates are far higher than in the past thanks to:

• Advanced monitoring systems
• Modern anesthetic drugs
• Intensive care facilities
• Progress in surgical technique

Do patients wake up straight away?

This varies with the type of operation. Some patients can be woken shortly after surgery. In other cases a period of controlled respiratory support in intensive care may be needed.

The aim is to wake the patient at the safest possible moment.

How is pain controlled?

In modern cardiac anesthesia the aim is not simply to get through the operation. Effective pain control, early breathing exercises and early mobilisation are important parts of treatment afterwards.

Multimodal approaches to pain treatment are therefore used.

Why is intensive care needed afterwards?

Patients require close follow-up after cardiac surgery. In intensive care the following are monitored closely:

• Heart rhythm
• Blood pressure
• Respiratory function
• Kidney function

This is usually a natural part of the operation and does not mean a complication has occurred.