Conscious Sedation

Patients today are participating more fully in their medical care. With improvements in technology and the increase in non-invasive surgeries, conscious sedation is a viable option, and can mean earlier discharge and lower hospital bills. But with this availability comes risks.

Conscious sedation is an effective and relatively inexpensive means of providing a patient with the most comfort during surgical procedures. When administered properly, the patient is able to maintain his/her own airway, remain comfortable and follow commands.

According to the American Society of Regional Anesthesia and Pain Medicine (ASRA) figures, as many as one in three patients undergoing an orthopedic procedure now requests regional anesthesia.¹Conscious sedation is rapidly becoming the most common type of procedural analgesic sedation for many procedures particularly in the fields of plastics, gastroenterology and endoscopy,” says Sandra Tunajek, CRNA, ND, director of practice at the American Association of Nurse Anesthetists (AANA). “These are not very comfortable procedures to undergo, and the patients don’t really want to know what’s going on. But they don’t really need to be under a general endotracheal anesthesia.”

Regional anesthesia is usually combined with a sedative to help the patient relax. That combination is used to place the patient in various stages of awareness, from fully awake and conversant to vaguely aware, with little or no memory of the surgery.

Advantages Over General Anesthetic

Tunajek cites the benefits of conscious sedation as rapid recovery, few side effects like nausea and vomiting, and drugs titrated to the individual needs of the patient. “Generally the drugs themselves are very fast-acting, and most of the time the patient is very aware and able to eat, drink and sit up right after the procedure,” she says. “Each facility has policies established for how long the patients have to stay after one of these procedures. It can vary from 30 minutes to two hours. It depends on what the procedure is and how the patient is doing.”

“The advantage of conscious sedation is that in its simplest sense, it can be done anywhere,” says Joseph A. Stirt, MD. “99.9 percent of general anesthetics happen in operating rooms.Conscious sedation can happen in an operating room, in a dentist’s chair, a doctor’s office — anywhere that medical care of any sort is given. Therefore, the number of people who can give conscious sedation multiplies as compared to those who can give a general anesthetic from the limited group of anesthesiologists and nurse anesthetists.” But, he warns, with this prevalence comes risk. “All of a sudden, anybody who can hold a syringe and push the plunger down can give conscious sedation, which means in some cases ancillary office personnel, office assistants, people who don’t have formal training in the administration of drugs. That opens up the practice of conscious sedation to basically anyone. You could give a ten year old the syringe, and say, ‘Whenever the patient complains, just give a little more of that drug.’ But the problem that you run into is that conscious sedation can become a general anesthetic. And when it becomes a general anesthetic, it becomes potentially much more lethal.”

Inherent Risks

“What happens, unfortunately a little bit too often, and what keeps my consulting business busy, are cases where the person who was administering the conscious sedation really wasn’t capable of understanding that he or she had crossed this sort of line — it’s not a line like stepping off a curb and you know you’re in the street. What you have here is kind of like a wheelchair ramp,” says Stirt. “The top is conscious sedation, and the bottom is general anesthetic. Somewhere along that ramp you get to a certain point where the patient is no longer conscious. To an untrained individual, that may not be clear.”

“The biggest risk for conscious sedation is when nonanesthesia providers giving the patient the sedation aren’t knowledgeable, educated or qualified to rescue that patient if something goes wrong,” says Tunajek. “The primary risk for sedation is that there is no set dosage for every patient. One size does not fit all. What is the tolerance level of one patient will not be tolerated by another. They need to be prepared for any worse-case scenario. I know these people are paying attention to what they’re doing, but it can become routine. And with anything that is routine, you just don’t think about what you’re doing half the time. It’s like driving a car and talking on a cell phone.”

The precise danger of the shift from being conscious to being unconscious, in practical terms of the endosurgical nurse, is the fact that unconsciousness is correlated with the lack of ability to control the airway. “What happens, in general, are two things: the absence of the patient’s ability to respond appropriately, and the ability to close the vocal cords should there be reflux and regurgitation from the stomach,” says Stirt. “The danger is not that the patient becomes unconscious per se, because an unconscious person will breathe, the heart will beat, blood pressure is fine. But should that patient have regurgitation or reflux of stomach contents, because of the administration of drugs that made the airway and the brain stem basically lose consciousness — those protective reflexes that immediately make you gag and choke and cough aren’t there, and that patient will aspirate.”

Tunajek also stresses the need for a thorough pre-op patient interview. “There is a real growing problem with the alternative therapy drugs that patients don’t tell you they are taking,” she says. “People don’t think about it, and the physician/nurse/anesthesiologist doesn’t think to ask the question. They’re taking drugs that they don’t think of as having any medicinal properties, so to speak. They don’t think about drug interaction, or prolonged bleeding times or other things that those over-the-counter herbal medicines can cause. That needs to be addressed in the pre-op interview.”

“When you sedate a patient with narcotics, you get respiratory depression,” continues Stirt. “These drugs depress the brain stem and respiratory centers. They decrease respiratory rate and volume. Along with the sedation is a decrease in gas exchange. Unfortunately, often the person administering sedation isn’t doing just that, but is doing a lot of other things. Overhead is high, and labor costs a lot of money. That person may be getting instruments, writing vital signs down, she may go to the head of the table and push some drugs, then run back and get another instrument that they need. Respiration doesn’t just stop, but slows down gradually, and the question is, How slow is too slow?”

Every patient is different. “I can be comfortable with someone breathing eight times a minute if I’m satisfied that they’re oxygenating well and that there’s enough gas exchange and blood pressure is okay,” says Stirt. “But other patients whose respiration drops to eight a minute may be shallow, they may have decreased cardiac output, may be retaining carbon dioxide, may be heading toward some cardiac arrhythmias. It’s not a matter of seeing how one patient does and giving the same dose to the next patient, because the dose response curve in terms of the drugs that we’re using is too great. When I start my anesthetics, I give small doses. I always titrate it in while I’m putting on my various monitors. Enough times that it’s remarkable and makes me pay very close attention and never turn my back on a patient, is that first cc will knock them out. I’ll turn to the patient and say, ‘Are you comfortable?’ and they’re out. That’s no longer conscious sedation — that’s a general anesthetic right there.”

As the trend for minimally-invasive surgeries continues, the use of conscious sedation will grow in tandem. “I’d say the curve is going to increase in slope as more and more cases are moved out of the operating room and moved into the radiologist’s suite, the endoscopy suite,” says Stirt. “My feeling is that most of these procedures have to be done, and they’re certainly not all going to be done in an OR, because nobody’s going to pay for it. So they’ll have to be done in a doctor’s office by whoever’s there. But I have to say that there is a small but real risk. Most of the time you can screw up and nothing happens. Most of the time people don’t screw up, so you’re talking about the times you do screw up and something bad happens. It’s not often, but it’s often enough if you’re that person.”

For a complete list of references, email: kdix@vpico.com .

“The problem that you run into is that conscious sedation can become a general anesthetic. And when it becomes a general anesthetic, it becomes potentially much more lethal.”

— Joseph A. Stirt, MD

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