23. GENERAL ANESTHESIA

The development of effective anesthesia to permit pain-free surgery must go down in the history books as one of the greatest achievements in medicine. Up until the mid-1800s, some physicians administered opiates or alcohol to patients to dull the pain of a surgical procedure. Other physicians tried hypnosis or distraction to divert a patient’s attention from the impending operation. Amputations, tumor removals, hernia operations, tooth extractions, and other surgical procedures were all performed when the patient was awake. This gruesome aspect of operations stopped with the development of drugs that could stop the sensation of pain and cause reversible unconsciousness.

None of us wants to feel a surgeon’s blade as it cuts through our skin. That’s where anesthesia comes to the rescue. Anesthetics are used to relax patients, eliminate their pain, and cause unconsciousness. Local anesthetics block pain to a small part of the body, but do not lead to loss of consciousness. These drugs can be used during minor surgical procedures such as stitching a small wound or having a tooth cavity filled. Regional anesthetics are used when a larger part of the body must remain pain free, for example, during surgery on the kidney or bladder or when a woman has a Cesarean section. Patients may either be awake or sedated during procedures using regional anesthetics. General anesthesia affects the entire body. It causes unconsciousness and is used during major operations, especially when the procedure will take a long time, when breathing is affected, or when there is a chance of significant blood loss.

Since the first use of ether in patients in the mid-1840s, anesthetic agents have been significantly improved such that pain-free surgeries are now routine. Nevertheless, being diagnosed with a condition or disease that requires a major operation is a source of anxiety for most people. Being anxious about an impending surgical operation is understandable when a person’s health depends on the outcome of the procedure. But in addition to surgeons and nurses in the operating room, anesthesiologists are present to monitor a patient’s vital signs (e.g., breathing, heart function, fluids, level of consciousness) as well as administer drugs to help a patient drift off to sleep and wake up after the surgery is completed. The dread of going under the knife is often heightened by the uncertainties associated with general anesthesia. In fact, a 2013 study found that preoperative anxiety was experienced by 81% of all surgical patients. Of those patients, 64.8% of the patients were afraid of not waking up after surgery, 42.8% were afraid that they would be aware during surgery, 41.8% were afraid that they would wake up during surgery, and 33.5% of the patients were concerned that anesthesia would paralyze them.

Statistically speaking, in the United States, approximately one person dies for every 100,000 people who receive general anesthesia. Almost half (46.6%) of the anesthesia-related deaths are caused by an overdose of anesthetics. The risk of dying from general anesthesia increases as people get older, with the elderly having the highest mortality risk.

Waking up in the middle of an operation has happened, and it is a particularly horrifying experience. Imagine being able to hear the sounds in the operating room. Even more terrifying is the thought of being paralyzed by drugs used during surgery that prevent a patient from crying out or moving. While under general anesthesia, a patient is monitored by an anesthesiologist who adjusts the drug regimen to prevent awareness and keep the patient sufficiently unconscious. Instruments to monitor brain function can also assist anesthesiologists in assessing the depth of anesthesia. Fortunately, the incidence of awareness or recall in patients who have had general anesthetics is extremely low. One study reported that only six of 87,361 (0.0068%) patients who received general anesthetics were classified as having awareness or recall of the surgery. The six patients who had some awareness or recall tended to be older and were under general anesthesia longer than patients who did not have any awareness or recall.

General anesthetics also have some less shocking potential side effects. Dizziness, nausea, and vomiting are not uncommon in patients who wake up after general anesthesia. Some people have a sore throat if a breathing tube was used or may have minor pain around the site of an injection. Some temporary confusion and memory loss, especially in elderly patients, may also occur. In rare cases, especially in elderly patients, the combination of surgery and anesthetics may cause a stroke and result in brain damage.

Patients can take several steps to reduce the risk of a poor surgical outcome that involves general anesthesia. Being in good physical shape can help reduce complications related to anesthesia. A history of smoking, obstructive sleep apnea, obesity, high blood pressure, alcoholism, and other conditions increases the risk of complications during surgery. Patients should consult with their doctors well in advance of the day of surgery and get all of their questions answered. For example, patients should ask their doctors if a local or regional anesthetic could be used instead of a general anesthetic. Some patients may have genetic factors that make them susceptible to the side effects of anesthesia. Therefore, patients should talk to family members who have had general anesthesia and ask about their experiences. If a relative has had a bad experience with general anesthesia, this information should be given to the patient’s doctors. Doctors will also ask questions and provide patients with important instructions about how to prepare for surgery. For example, doctors will want to know about a patient’s allergies to medicines and whether the patient is taking any drugs (including recreational drugs), medications, vitamins, or supplements. This information will be used to avoid chemical interactions with anesthetics that will be given. Patients will likely be told not to eat anything the night before surgery. This is to prevent patients from vomiting food that could block oxygen from getting to the lungs or that could be inhaled into the lungs and cause pneumonia.

Anesthesia will always have some risks, but consider the alternative. There are few people who would refuse the benefits and comfort of a pain-free surgery.

SUMMARY

Preventability (41)

If you must have major surgery, you will want general anesthesia, and there is not much you can do to avoid it. However, patients should provide a full medical history and can ask their doctors questions about anesthetic choices to avoid potential problems.

Likelihood (5)

General anesthesia is safe for most people, most of the time.

Consequence (88)

The prospect of waking up during surgery is fairly terrifying, and the side effects of general anesthesia vary in degree. In rare instances, general anesthesia can kill.

REFERENCES

Li, G., Warner, M., Lang, B. H., Huang, L., & Sun, L. S. (2009). Epidemiology of anesthesia-related mortality in the United States, 1999–2005. Anesthesiology, 110, 759–765.

Mavridou, P., Dimitriou, V., Manataki, A., Arnaoutoglou, E., & Papadopoulos, G. (2013). Patient’s anxiety and fear of anesthesia: Effect of gender, age, education, and previous experience of anesthesia. A survey of 400 patients. Journal of Anesthesia 27, 104–108.

Pollard, R. J., Coyle, J. P., Gilbert, R. L., & Beck, J. E. (2007). Intraoperative awareness in a regional medical system: A review of 3 years’ data. Anesthesiology, 106, 269–274.