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Anesthesia Q and A with Alex Macario, MD

Updated: Nov 14, 2019

Recently, I received a phone call from a friend. Unfortunately, she shared with me that her father has colon cancer and needs to have surgery. She had many questions concerning the upcoming operation in terms of the anesthetic that would be used. I thought it would be valuable to present some of her questions in a Q & A format. My colleague, Alex Macario, MD, professor of anesthesia at Stanford, agreed to answer the questions. —Jeanne

What kind of training does an anesthesiologist need? Following the four years of medical school, one has to complete four years of an anesthesia residency. Many anesthesiologists go on to do additional training in the form of a one-year fellowship in a subspecialty of anesthesia. Subspecialties include critical care medicine to work in an ICU, cardiac anesthesia, obstetric anesthesia, pain medicine and pediatric anesthesia.

What happens during the preoperative visit? When a patient with colon cancer, for example, is scheduled for surgery, the anesthesiologist will see them in the preoperative clinic. Hospitals handle the preoperative clinic differently—some do it through a detailed phone call, others require a visit to a clinic a few days before surgery, still others handle the assessment the day of the surgery. The doctor will conduct an overall health assessment and, based on their findings, present an individualized anesthetic plan that works best for that patient.

It is useful to communicate with your anesthesiologist any concerns you may have about the anesthesia during this visit—particularly if you've experienced delayed awakening or severe nausea and vomiting after a surgery. There are a variety of tools and techniques and drugs that the anesthesiologist can choose from to customize an anesthetic to meet the patient’s needs. For example, if a patient had severe nausea after surgery in the past performed with general anesthesia, it may be possible to undergo the scheduled surgical procedure with a nerve block that completely numbs the arm, leg or portion of the body that’s being operated on. In addition, there is an array of drugs that can be used to help ease nausea.

Everyone involved in caring for the patient has a common objective: to do everything they can to help the patient have the best possible results with the fastest and safest recovery. When scheduled for surgery be sure to ask the anesthesiologist any questions you may have regarding the available options for the different types of anesthesia.

Can you differentiate between conscious sedation and general anesthesia? Is there a difference between these two different modalities in terms of physiologically altering our body?

Great question! It may be useful to think about those terms as a continuum or, in other words, a spectrum of the depth of anesthesia. The American Society of Anesthesiologists defines Moderate Sedation/Analgesia (conscious sedation) as a drug-induced depression of consciousness during which patients respond purposefully to verbal commands, either alone or accompanied by light tactile stimulation. With this level of sedation, the patient breathes on their own without support from the anesthesiologist. As the patient becomes increasingly anesthetized, the patient can transition in this consciousness continuum to deep sedation. In this state, patients cannot be easily aroused but respond purposefully following painful stimulation such as rubbing the patient's sternum to stimulate them to awaken. The ability to breathe fully on their own is usually impaired with deep sedation. Furthest along this continuum is general anesthesia during which patients are not arousable, even by painful stimulation. The anesthesiologist has to assist the patient to maintain lung ventilation and breathing by inserting a tube in the windpipe for example. While in surgery, is the anesthesiologist there at all times?  If the patient has surgery at a community hospital where there is not a residency program, then the fully trained anesthesiologist, called the attending, is in the operating room the entire time. If the patient has surgery at an academic center, then the attending anesthesiologist will often supervise the resident anesthesiologist in training. The attending may leave the room, depending on the experience of the resident and the difficulty of the case. However, it is important to know there will be an anesthesiologist in the operating room at all times.

What is the anesthesiologist doing during the surgery? The anesthesiologist chooses a combination of medications and techniques that best suit the patient’s medical history. Once the patient enters the operating room, various monitors are applied that continually check the patient’s blood pressure, heart rate and oxygen saturation. Medications are administered through an intravenous catheter (IV) to put the patient to sleep (if a child is anesthetized, they are often put to sleep with anesthetic gases through a mask first). Additional medications may be given to help prevent movement and memory of the surgery and/or to provide pain control. At all times, the anesthesiologist is working to ensure the patient's blood pressure, heart rate and oxygenation remain at normal levels. Typically, a tube is placed in the trachea so that a ventilator can deliver breaths to the patient. Throughout the procedure, the anesthesiologist works closely with the surgeon to ensure the safest experience for the patient.

Are there new techniques being employed in the operating room that help make the surgical outcome more successful? Yes. An example of one such innovation is an Enhanced Recovery After Surgery protocol. Hospitals that use this protocol reduce the number of complications and the length of stay by making several important modifications to the traditional anesthesia protocol. These changes include the following:Have the patient take a carbohydrate drink two hours before surgery (instead of the traditional nothing to eat or drink for eight hours before surgery);Have the surgeon use minimally invasive approaches (instead of large open incisions) that injure less of the body’s tissue during the operation;Avoid large volumes of intravenous fluids during the time the patient is in the operating room (instead of the traditional liberal administration of intravenous fluids);Encourage the patient to get out of bed soon after surgery (instead of being sedated and immobile in the hospital bed for a couple of days after surgery); andRecommend the patient begin food and drink intake as quickly as possible, sometimes even soon after the surgery (instead of delaying resumption of eating for several days). Does going on an exercise program to increase fitness before surgery (such as for colon cancer) help with recovery after the surgery? A number of studies have reviewed this question. Each of the available published studies looked at the outcomes a little bit differently, so it isn't possible to answer this question conclusively. The idea is a good one, in theory. Analogous to an athlete training for a competition, preparing the mind and body for the stress of surgery and recovery by increasing one’s functional capacity makes intuitive sense. However, the studies found that better exercise function did not translate to better recovery and fewer complications.

How long does it take to fully recover your physical and mental faculties, especially after general anesthesia?

Patients can expect to have their mental function be back to normal soon after surgery and general anesthesia, so they can answer emails and tend to other duties as soon as they get home. However, the published research indicates that some patients suffer from postoperative brain dysfunction, which can be subtle; for example, it may take them a little bit longer to finish the crossword puzzle. Elderly individuals may be at particularly high risk for this decline which may take months to fully resolve. The cause is unknown but is probably related to surgical stress, perhaps the other medical issues the patient has such as high blood pressure, baseline brain frailty, and perhaps even the anesthetic drugs. More studies are being done to try to better understand the mechanisms and the things that can be done to minimize the risk of mental decline after surgery and anesthesia.

Are there any risks for anesthesia?  The more common but less serious risks of general anesthesia include a sore throat, nausea and vomiting postoperatively. Sometimes a patient can get a chipped tooth. Rarer yet more serious risks include awareness intraoperatively, a heart attack, or even death from something like an anaphylactic reaction to a medication. However, the anesthesiologists are well trained to avoid these types of complications. If these issues do arise, the anesthesiologists are highly trained experts and well prepared to treat them. Patients should know that anesthesia in 2018 is extraordinarily safe.


"Continuum of Depth of Sedation: Definition of General Anesthesia and Levels of Sedation/Analgesia," American Society of Anesthesiologists:

Alex Macario, MD

Alex Macario spent the first decade of his life in Europe with his scientist parents in Sweden, Italy and France. He finished high school in Albany, New York, and attended the University of Rochester on a Joseph C. Wilson Merit Scholarship. 

Alex completed his undergraduate, medical school and business school education at the University of Rochester. He then trained in the anesthesiology residency at Stanford University, went on to serve as chief resident, and completed a postgraduate fellowship in health services research.

Alex is a professor in the department of Anesthesiology, Perioperative and Pain Medicine and, by courtesy, also in the department of Health Research and Policy at the Stanford University School of Medicine. He is also vice-chair for education and program director for the Stanford anesthesiology residency program. Alex has, additionally, led the creation of multiple innovative education initiatives and is the recipient of numerous honors and awards.

300 Pasteur Drive, H3580 Stanford University School of Medicine Stanford, California 94305 (650) 723-6411

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