Types of Anaesthesia
During surgery, you will be given some form of anaesthesia, which is medication administered for the relief of pain and sensation during surgery. The type and dosage of anaesthesia is administered by the anaethetist. When a patient faces surgery, he or she will meet with the anaethetist before the procedure. The anaethetist will review the patient’s medical condition and history to plan the appropriate anaesthetic for surgery.
There are various forms of anaesthesia. The type of anaesthesia you will receive will depend on the type of surgery and your medical condition. Usually, an anaethetist will administer a sedative in addition to the anaesthetic. The different types of anaesthesia include the following:
- Local anaesthesia. Local anaesthesia is an anaesthetic agent given to temporarily stop the sense of pain in a particular area of the body. A patient remains conscious during a local anaesthetic. For minor surgery, a local anaesthetic can be administered via injection to the site. However, when a large area needs to be numbed, or if a local anaesthetic injection will not penetrate deep enough, doctors may use regional anaesthetics.
- Regional anaesthesia. Regional anaesthesia is used to numb only the portion of the body that will receive the surgical procedure. Usually an injection of local anaesthetic is given in the area of nerves that provide feeling to that part of the body. There are several forms of regional anaesthetics, two of which are described below:
- Spinal anaesthetic. A spinal anaesthetic is used for lower abdominal, pelvic, rectal, or lower extremity surgery. This type of anaesthetic involves injecting a single dose of the anaesthetic medication into the subarachnoid space, which surrounds the spinal cord. The injection is made into the lower back, below the end of the spinal cord, and causes numbness in the lower body. In some situations, such as a prolonged procedure, continuous spinal anaesthesia may be used. A thin catheter (hollow tube) is left in place in the subarachnoid space for additional injections of the anaesthetic agent, which ensures numbness during the length of the procedure.
- Epidural anaesthetic. The epidural anaesthetic is similar to a spinal anaesthetic and is commonly used for surgery of the lower limbs and during labor and childbirth. This type of anaesthesia involves continually infusing an anaesthetic medication through a thin catheter (hollow tube). The catheter is placed into the space that surrounds the spinal cord in the lower back (just outside the subarachnoid space), causing numbness in the lower body. Epidural anaesthesia may also be used for chest or abdominal surgical procedures. In this case, the anaesthetic medication is injected at a higher location in the back to numb the chest and abdominal areas.
- General anaesthesia. General anaesthesia is an anaesthetic used to induce unconsciousness during surgery. The medication is either inhaled through a breathing mask or tube, or administered through an intravenous line (a thin plastic tube inserted into a vein, usually in the patient’s forearm). A breathing tube may be inserted into the windpipe to maintain proper breathing during surgery. Once the surgery is complete, the anaethetist ceases the anaesthetic and the patient is taken to the recovery room for further monitoring.
About your Anaethetist
Anaethetists are the doctors trained to administer and manage anaesthesia given during a surgical procedure. They are also responsible for managing and treating changes in your critical life functions–breathing, heart rate, and blood pressure–as they are affected by the surgery being performed. Further, they immediately diagnose and treat any medical problems that might arise during and immediately after surgery.
Prior to surgery, the anaethetist will evaluate the patient’s medical condition and formulate an anaesthetic plan that takes that patient’s physical condition into account. It is vital that the anaethetist knows as much about your medical history, lifestyle, and medications, including over-the-counter and herbal supplements, as possible. Some particularly important information he or she needs to know includes the following:
- Reactions to previous anaesthetics. If you have ever had a bad reaction to an anaesthetic agent, you need to be able to describe exactly what the reaction was and what your specific symptoms were. Give the anaethetist as much detail as possible, such as you felt nauseated when you woke up or the amount of time it took you to wake up.
- Current herbal supplements. It has recently been learned that certain herbal products, commonly taken by millions of Americans, may cause changes in heart rate and blood pressure, and may increase bleeding in some patients. The popular herbs gingko biloba (an herb used for many conditions associated with aging, including poor circulation and memory loss), garlic (an herb often used for cardiovascular conditions and to help prevent colds, flu, and other infectious diseases), ginger, and ginseng (used as a general tonic to increase overall body tone; considered helpful in elevating energy levels and resistance to stress) may lead to excess blood loss by preventing blood clots from forming. In addition, St. John’s wort (a popular herb used for mild to moderate depression) and kava kava (another popular herb used for depression and to elevate mood) may prolong the sedative effect of the anaesthetic. The American Society of Anaethetists advises patients planning to have surgery to stop taking all herbal supplements at least two to three weeks prior to surgery to rid the body of these substances.
- Any known allergies. Discussing any known allergies with the anaethetist is very important, as some anaesthetic drugs trigger cross-allergies, particularly in people who have allergies to eggs and soy products. Allergies to both foods and drugs should be identified.
- Recent and/or current prescription and over-the-counter medications. It is also important to let your surgeon and anaethetist know about both prescription medications and over-the-counter medications you are taking, or have recently taken. Certain prescription medications, such as coumadin, a blood thinner, must be discontinued for some time prior to surgery. In addition, as many people take a daily aspirin to prevent heart attack, and certain dietary supplements, doctors need to be aware of these habits, as they can prolong bleeding and interfere with muscle relaxants used by anaethetists.
- Cigarette smoking and drinking. Cigarette smoking and alcohol can affect your body just as strongly (and sometimes more strongly) than many prescription medications you may be taking. Because of the way cigarettes and alcohol affect the lungs, heart, liver, and blood, these substances can change the way an anaesthetic drug works during surgery. It is important to let your surgeon and anaethetist know about your past, recent, and current consumption of these substances prior to surgery.
Undergoing surgery can be a good motivator to quit smoking. Most hospitals are smoke-free and doctors, nurses, and other health professionals will be there to give you support. In addition, you will heal and recover faster, especially in the incision area, or if your operation involves any bones. Quitting smoking also reduces your risk of heart disease and cancer.
- Use of street drugs (such as marijuana, cocaine, or amphetamines). Patients are often reluctant to discuss matters of illegal drug consumption, but you should remember that all conversations between you and your surgeon and anaethetist are confidential. It is crucial that he or she know about your past, recent, and current consumption of these substances. It is important to keep in mind that the only interest your doctor has in this information is learning enough about your physical condition to provide you with the safest anaesthesia possible.
Meeting the Anaethetist before the surgery
Because anaesthesia and surgery affect every system in the body, the anaethetist will conduct a preoperative interview. Sometimes this is done in person; in other cases, the anaethetist will interview you over the telephone. During this interview, the anaethetist will review your medical history, as well as discuss the information mentioned above. He or she will also inform you about what to expect during your surgery and discuss anaesthetic choices with you.
If you have not personally met during the preoperative interview, the anaethetist will meet with you immediately before your surgery to review your entire medical history as well as results of any medical tests previously conducted. By this time, he or she will have a clear understanding of your anaesthetic needs.
How are pre-existing medical conditions handled during surgery?
If you have a pre-existing medical condition, such as diabetes, asthma, heart problems, or arthritis, your anaethetist will have been alerted to this and will be well-prepared to treat these conditions during your surgery, as well as immediately afterward. Anaethetists are trained to handle sudden medical problems related to the surgery, as well as any chronic conditions that may need attention during the procedure.
How is the patient’s condition monitored during surgery?
Monitoring is one of the most important roles the anaethetist handles during surgery. Second-by-second observation of even the slightest changes in a wide range of body functions gives the anaethetist a tremendous amount of information about the patient’s well-being. In addition to directing your anaesthesia, the anaethetist will manage vital functions, such as heart rate, blood pressure, heart rhythm, body temperature, and breathing. He or she will also be responsible for fluid and blood replacement, when necessary. Sophisticated technology is used to monitor every organ system and its functioning during surgery.