When facing surgery or an invasive procedure, anesthesia is one of the things we worry about. Will we feel pain? Will we be completely asleep? Will we wake up? Fortunately, the science of anesthesia has progressed dramatically in recent years, reducing the risks and side effects associated with old inhaled drugs such as ether and increasing our options for painless, anxiety-free surgery.
Strictly speaking, anesthesia is the effect produced by drugs that block nerve impulses and leave the body or part of the body more or less insensitive to pain. The effects range from a short-lived numbness of a patch of skin or an extremity, to complete loss of sensation, unconsciousness, and temporary paralysis. Nowadays, anesthesia also includes medications that relieve anxiety and post-procedure pain, control of nausea and vomiting and, sometimes, even blocking our memories of the events during a procedure.
Most of us have received injected local anesthetics for minor procedures, such as dental work or stitching a cut. But when we think of anesthesia, what comes to mind is either regional or general anesthesia. These are usually administered by an anesthesiologist — a doctor who has a fully certified postgraduate training in the specialty. Anesthesiologists perform nerve blocks, provide general or regional anesthesia, and monitor life functions during surgery.
Regional Anesthesia
Procedures such as a cesarean section or surgery on an arm or leg may require regional anesthesia. The anesthetic is injected into clusters of nerves supplying the area that needs numbing, much as a dentist may numb the whole lower jaw when filling a cavity. To numb the entire lower body, the anesthetic agent is injected into the spine at the place where the nerves serving the area originate. This technique is used for childbirth, certain lower abdominal procedures, and some hip and leg surgeries. There are two such nerve blocks — epidural and spinal (see illustration on Page D-2).
To perform an epidural, the anesthesiologist inserts a thin tube (polyurethane catheter) between two vertebrae, just outside the spinal cord. The catheter is left in place so that small amounts of anesthetic can be added when necessary. An epidural can be used for hours or even days, so it’s ideally suited for controlling postoperative pain or the pain of a long labor or delivery. A spinal block, on the other hand, is injected just once, directly into the fluid surrounding the spinal cord, affecting both sensory and motor functions. It works faster than an epidural and makes use of a smaller volume of anesthetics to produce such blockade.
General Anesthesia
Extensive surgical procedures usually require general anesthesia. General anesthesia puts the patient into a deep unconscious state and provides a “quiet” operative field for the surgeon with an optimum muscle relaxation. To achieve the ideal balance, the anesthesiologist combines sleep-inducing agents such as narcotics and hypnotics, anesthetic inhalation agents, potent opioid analgesics, and muscle relaxants. Most of these medications are administered through a cannula inserted into a vein before surgery.
Preoperative medications may include opioids, antiemetic drugs, potent analgesics, and hypnotics, for relieving anxiety and apprehension, and for preventing nausea. Some preop medications act on the brain to help block any memory of the procedure. Drugs such as barbiturates are given to induce unconsciousness. Anesthesia is maintained with the use of either gas or intravenous anesthetics with reversible muscle relaxants and opioid analgesics. A breathing tube is placed into the airway to assist or control respiration during surgery. This is later connected to a ventilator. Another option is the use of a laryngeal mask airway which is introduced into the mouth. Following surgery, the effects of the anesthetics are reversed by other drugs or the patient may simply wake up as the medications wear off. During anesthesia, the patient is hooked to monitors to vigilantly watch the vital signs and keep the patient in optimum condition.
Post-Surgical Concerns
To make sure that your post-surgical pain is adequately addressed, discuss your options with your anesthesiologist before surgery. An epidural catheter can reduce the dose of medications you need. A patient-controlled analgesia pump lets you give yourself doses of pain medication by vein. You may need intravenous or oral analgesics, such as acetaminophen (Tylenol) or non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen or naproxen or celecoxib. You may also want to familiarize yourself with relaxation techniques, such as deep breathing, meditation, or visualization.
Nausea and vomiting are common after surgery, due either to the surgical procedure itself, or, less often, to specific anesthetic drugs. Fortunately, anti-nausea drugs have become so effective that today, patients can expect to have few, if any, problems with nausea following surgery. Anesthesiologists commonly give such drugs in advance to people who are likely to develop problems. Pre-emptive control of postoperative nausea and vomiting (PONV) is a very effective method that some routinely administer them to all those undergoing surgery. Let your anesthesiologist know about any experience you’ve had with anesthesia and discuss plans to prevent and treat any nausea or vomiting that may develop. It’s common to feel fatigue after an operation, due either to the physical stress of the surgery or to the anxiety surrounding it. Depending on the surgery, your body may need a few days to weeks to recover.
Anesthesia’s Long-Term Effects
Many people wonder whether anesthesia has other lingering effects, especially on the brain. Research and experience suggest that surgery under general anesthesia may affect cognitive function — a postoperative concern for patients and physicians alike. Decline in cognitive ability following surgery was originally recognized as a complication of heart surgery, particularly in the elderly. It’s now been studied in a range of other situations, including major non-cardiac operations and more minor procedures.
One week after major non-cardiac surgery, cognitive difficulties, such as problems with attention and concentration, occur in about 25 percent of people over age 60. Fortunately, careful testing shows that this complication is usually temporary. After three months, the rate drops to 10 percent and after one to two years, to one percent. Patients undergoing minor surgery — particularly outpatient procedures — are at a lower risk because they’re not under anesthesia as long and require fewer postoperative medications. Complaints of cognitive decline following surgery may result from increased awareness of aging and possibly from depression. If you feel that your brain isn’t working as well after surgery, you’re not alone, and don’t despair. You’re likely to be back to normal within a few weeks. You can also help things along by keeping your brain active with reading, interacting with friends, and trying to keep up your usual routine as best you can during your recovery.
Preoperative Steps Help Keep You Safe
One of the most important things you can do to keep yourself safe is to have a thorough preoperative discussion with your anesthesiologist. It’s an important opportunity to provide him/her with information vital to your care and for you to express your wishes about anesthesia and postoperative pain control. Your medical history is important. Mention any previous adverse reactions to anesthesia. Bring a list of all the prescription and over-the-counter medications you take. For example, aspirin and other NSAIDs can interfere with blood clotting and will need to be discontinued up to two weeks before surgery. Be sure to mention any supplements or herbal products you take. Several herbs — such as St. John’s wort, feverfew, valerian, ginkgo, and ginseng — can cause problems with bleeding or blood pressure during surgery or interact with anesthesia medications. Make note of any allergies. And be sure to report any loose teeth, dentures, or crowns; they could be damaged if a tube is placed into your throat to help you breathe. Ask about eating, drinking, and medication use before surgery.
The preoperative interview is also a good time to learn what to expect when you wake up from surgery. For example, some anesthetics are more likely to produce nausea or headaches than others. It’s also wise to find out how long the effects of anesthesia may last. Understanding your options and knowing what to expect will increase your chances of having a smooth surgical experience and recovery.