Marie remembers having general anesthesia to have her wisdom teeth removed several decades ago. Next week, she’ll have a much more invasive heart procedure but will remain conscious the whole time. Her doctor assures her that she should have no discomfort.
Sedation, along with analgesia or local anesthesia to relieve pain, is now used for many procedures that once required general anesthesia, and the distinction may be hard for some to understand. How can I feel comfortable if I’m awake while someone is cutting into my body or pushing a tube down my throat? Marie thought.
As with all fields of medicine, anesthesia is constantly changing. At one time, opium and alcohol were the only known anesthetics; neither was very effective unless used in doses high enough to cause major problems. In the 1840s, ether and nitrous oxide (known at the time as “laughing gas”) emerged as more effective options. The first local anesthetic was cocaine, and many drugs used today (lidocaine, novacaine, tetracaine) are chemically similar but with fewer risks.
With numerous drug options today, doctors can offer the patient a combination that will provide the greatest comfort and the quickest recovery at the lowest risk.
GENERAL ANESTHESIA: As Marie knows, there are advantages to being “knocked out” or rendered unconscious even for having wisdom teeth pulled. You don’t feel or remember anything–even the anxiety of knowing you’re being worked on or the discomfort of being in one position for an extended period. You go to sleep, and when you wake up, the whole thing is over.
Doctors still recommend general anesthesia for procedures that take a long time (such as knee replacement) or affect breathing (heart bypass surgery).
Risks are relatively high, however, so it’s necessary to meet with the doctor ahead of time to discuss your medical history, allergies and habits such as smoking and alcohol use. It’s imperative to tell your doctor about all of the medications, vitamins and supplements you’re taking (since some can increase bleeding) and to follow instructions carefully about food and liquid intake in the hours before the procedure. It’s possible during general anesthesia to breathe in the contents of the stomach, creating a life threatening situation.
During general anesthesia, the muscles of the chest are relaxed enough that a breathing mask or breathing tube is needed to keep your airways open. You’ll also be hooked to machines that continuously monitor heart rate, blood pressure, respiratory rate, oxygen and carbon dioxide levels, temperature, brain activity and the concentration of the anesthetic.
The anesthetic is administered through inhalation and/or an intravenous line until the procedure is completed. Even then, however, the patient must be monitored for three or four hours–sometimes overnight–in an anesthesia care unit.
Common side effects include shivering, nausea (perhaps vomiting), headache, sore throat from breathing tube and disorientation that may linger for awhile. More serious side effects such as suffocation, allergic reaction, organ failure, stroke and heart attack are rare but nevertheless possible.
With the monitoring technology available today, the risk of death with general anesthesis is less than 1 in 100,000. With the other options now available, however, it is rarely the first choice except for difficult, complex procedures.
REGIONAL ANESTHESIA: Wheareas local anesthetics are injected just under the skin to block pain at the site, regional anesthesia goes further along the nerve path leading to the brain, blocking signals from a central nerve or cluster of nerves.
For carotid endarterectomy, for example, effective pain relief can result from numbing the cervical plexus, an intersection of several nerves on the side of the neck.
For Cesarean births, most women today prefer a spinal or epidural that results in loss of sensation from the waist down but allows the mother to remain conscious. These are also used for lower abdominal surgery and, in some cases, hip or knee replacement.
Sometimes it’s something other than pain that triggers anxiety. One woman who had a spinal for a C-section birth commented that she could feel the pressure of being cut open even though she had no pain. Individuals undergoing hip or knee replacement might become concerned about the sawing or grinding noises they hear.
SEDATION: A sedative is a tranquilizer, and sedation is the state of being calmed. Children–and adults–undergoing dental procedures benefit from being calmed. And so do individuals undergoing cosmetic surgery, colonoscopy or cardiac catheterization.
There are several levels of sedation, ranging from the mild effect of nitrous oxide in the dental chair to the deeper sedation used for surgical procedures. Sedation is usually combined with a local anesthetic or an analgesic such as fentanyl to relieve the pain.
In most cases, you remain awake during procedural sedation and can answer questions but are relaxed, sleepy and unconcerned about the project at hand. If something unpleasant happens (such as the shocking of the heart during a cardioversion procedure), your memory of it will be blunted.
Drugs are often similar to or the same as those used for general anesthesia. And at the deepest level, there may be little difference in effect. In most cases, though, a breathing tube is not needed for procedural sedation.
Patients require monitoring to make sure they don’t slip into deeper stages of sedation. Generally, though, the monitoring required is much less since the doctor can rely on the patient for feedback.
Recovery is also much quicker than with general anesthesia. In many cases, depending on the nature of the procedure, the patient is able to go home within 30 to 40 minutes after the end of the procedure.
Each type of anesthesia has its own benefits and drawbacks, and your doctor is likely to prefer one based on your individual needs and what the doctor and anesthesiologist are comfortable performing. Which one you choose, though, is ultimately a decision to be made between you and your medical team. Make sure you ask questions and have all the information you need to make a good decision for your comfort and peace of mind.
REFERENCES:
American Dental Association, “Guidelines for the use of sedation and general anesthesia by dentists,” October, 2007.
“Anesthesia–risks and complications,” WebMD Pain Management Health Center, last updated January 28, 2010.
“Anesthesia: numbed by choices,” Harvard Health Letter, December, 2006.
“Anesthesia and how to prepare for it,” Harvard Women’s Health Watch, January, 2005.
“Conscious sedation for surgical procedures,” MedlinePlus, updated by Shabir Bhimjii, M.D., Ph.D., January 26, 2011.
Shanna Freeman, “How anesthesia works,” Howstuffworks.com.
James R. Hebel, “Regional anesthesia,” MayoClinic.com.
Christopher J. Lettieri, M.D., “Current concepts in intensive care unit sedation,” Medscape Pulmonary Medicine, September 9, 2009.
“Mayo Clinic Proceedings: study finds significant decrease in postoperative delirium in elderly patients,” Mayo Clinic Proceedings, January 18, 2010.
Mayo Clinic Staff, “General anesthesia,” MayoClinic.com, June 26, 2010.
Lee Robinson, M.D., “Benefits of I.V. sedation vs. general anesthesia,” drleerobinson.net, December 29, 2010.
Ricardo L. Rodriguez, M.D., “IV sedation vs general anesthesia,” Plasticsurgery.com, 2009.
C. Sorensen, et al, “Comparison of intravenous sedation versus general anesthesia on the effficacy of the doli 50 lithotriptor,” Journal of Urology, July, 2002.
06/28/2012
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