It is a far more involved and all-encompassing role than one may think: anesthesiology inherently spans the continuum of care.
Anesthesiologists are involved during the assessment of a patient prior to a surgical procedure to understand their medical history, medication tolerance, and to estimate risks before, during and after operation.
During a surgical procedure, an anesthesiologist's primary function is to assess and manage patients' vital functions, minimize discomfort, and provide optimal conditions for surgery to be performed. In the postoperative period, anesthesiologists continue to ensure patients optimal recovery from anesthesia and surgery.
Dr. George Djaiani likens it to flying an airplane.
"Our operating room encounters are commonly compared to pilot's work with takeoff – for us known as the induction of anesthesia," he explains. "Then we cruise, sometimes even with bad turbulence. Finally, it's time for landing, which in our world is the patient waking up."
Anesthesiologists like Dr. Djaiani now play a crucial role in the 'awake TAVI,' or transcatheter aortic valve implantation - a procedure pioneered in Ontario by the Peter Munk Cardiac Centre.
TAVIs are performed on patients suffering from severe aortic stenosis. This condition occurs when the heart's aortic valve is prevented from opening completely. The narrowing of the aortic valve prevents blood flow from the heart to the rest of the body. It results in the heart working harder to pump blood, which could lead to a host of serious heart conditions and, in the worst cases, death.
Until recently, patients undergoing a TAVI procedure would be put under general anesthesia. That changed in January 2015, when a medical team at the PMCC performed a TAVI on a patient who was kept awake intentionally.
Dr. Djaiani provides a behind-the-scenes look at the anesthesiologist's role in such a procedure.
What is the anesthesia department's role during an 'awake TAVI' procedure?
Strictly speaking, it is not really an 'awake TAVI', but rather a 'conscious sedation' state, in which the patient is in a sort of twilight zone.
The conscious sedation can be either deepened, or converted to general anesthetic if the need arises. The patient is sedated, or sleepy, but is able to respond to verbal commands. The anesthesiologist keeps an eye on the patient's vital signs - such as heart rate, blood pressure, and breathing – to ensure the patient is comfortable and safe.
How would you describe 'conscious sedation' and how is it achieved?
Conscious sedation means that the patient is relaxed, sedated, pain free, but the verbal contact can always be maintained.
If the verbal contact is lost then it is a general anesthesia, which is kind of a fine line. It is usually achieved by a combination of drugs (sedatives and opioid analgesics), for example, midazolam, and fentanyl. If an anesthesiologist is not present during general anesthesia, it may endanger a patient's life. Some of the side effects patients may experience from general anesthesia include drowsiness, a sore throat, nausea, vomiting, dizziness, blurred vision, short-term memory loss, delirium, low blood pressure, and breathing problems.
We have started to use a drug called dexmedetomidine for conscious sedation that has many favourable properties over the currently-used sedation techniques. In fact the first 'awake TAVI' patient at UHN received dexmedetomidine.
How has anesthesia made 'awake TAVIs' possible?
This type of anesthesia has been used for a long time in different patient populations such as, dental anesthesia, colonoscopies, and cardiac catheterization procedures, with great success.
We have only recently introduced it for TAVIs in our institution, although it has been successfully used in Europe and the United States for some time. One of the goals of the 'awake TAVI' is an earlier recovery and a shorter length of stay at the hospital.
Are there an increasing number of cases/circumstances in which general anesthesia is no longer employed?
There has been a great expansion in minimally-invasive surgical procedures outside of the operating room, such as interventional cardiology and interventional radiology; and in office-based practices, such as dentistry procedures, colonoscopies, and gastroscopies. These do not require general anesthesia and the conscious sedation is a method of choice.
What are the top three current trends in anesthesia in general and at UHN specifically?
Ultrasound-guided procedures, prevention of chronic pain, and facilitated early recovery are the top three trends in anesthesia.
In the Anesthesia department at UHN we are particularly focused on the use of ultrasound and point of care testing (which involves coagulation, and platelet work) to guide blood product transfusion. We are also working to facilitate early recovery, prevent delirium, and expand the conscious sedation strategy to patients undergoing TAVI procedures.
How would you describe the importance of an anesthesiologist to a medical team?
Anesthesiologists are perioperative physicians. That means we are part of the preoperative visit, we help find ways to optimize the patient's condition, we understand their surgical needs, and then we plan the appropriate anesthetic technique and monitoring.
The next step includes the intraoperative period, which consists of induction and maintenance of anesthesia during surgery and monitoring the patient's vital signs. After the surgery is done, we must help to decide on the patient's disposition, for example should they be taken to the post-anesthesia care unit, or intensive care unit. Furthermore, we look after postoperative pain management for the patient.
We are there to make sure nothing bad happens to the patient.
What is the most common misconception about anesthesia?
I often find that many people don't know that anesthesiologists are firstly physicians, and secondly specialists.
DID YOU KNOW:
An awake TAVI:
Where are we moving when it comes to cardiac anesthesiology?
We are moving towards minimally invasive cardiac surgery, which requires more involved echocardiography surveillance in the operating room. We are seeing more and more peripherally inserted ventricular assist devices – also known as mechanical hearts – in patients with heart failure.
More complex catheterization lab procedures in sicker patients also mean there's more of a need for conscious sedation and we're also seeing more TAVI patients who need conscious sedation during their procedures.
Is there anything else you'd like to add?
Pertinent to the TAVI program, I would emphasize the importance of cardiac or heart teams that include an interventional cardiologist, an anesthesiologist, a cardiac surgeon, an intensive care specialist, and a geriatrician/psychiatrist to ensure a high level of cohesion between all parties involved. This approach facilitates a seamless perioperative course and the best possible outcomes for our patients.