Intravenous Conscious Sedation (aka “IV sedation”) is when a drug, usually of the anti-anxiety variety, is administered into the blood system during dental treatment.
What does it feel like? Will I be asleep?
A lot of dental offices and practices use terms such as “sleep dentistry” or “twilight sleep” when talking about IV sedation. This is confusing, because it suggests that IV sedation involves being put to sleep. These terms are more descriptive of deep sedation. Deep sedation isn’t commonly used (in the U.K. at least), and is classified as general anaesthesia (even though sedation occurs on a continuum).
In reality, you remain conscious during conscious IV sedation. You will also be able to understand and respond to requests from your dentist.
However, you may not remember much (or anything at all) about what went on because of two things:
- IV sedation induces a state of deep relaxation and a feeling of not being bothered by what’s going on
- the drugs used for IV sedation produce either partial or full memory loss (amnesia) for the period of time when the drug first kicks in until it wears off. As a result, time will appear to pass very quickly and you will not recall much of what happened. Many people remember nothing at all. So it may, indeed, appear as if you were “asleep” during the procedure.
First-hand accounts of IV sedation
“Basically, its just a tiny pinch in the back of the hand and in goes the ‘stuff’. Nothing happens for several seconds and then you begin to feel light-headed (a little drunk) for a few moments, which is not unpleasent. Then instantly several hours have magically passed and everything has been done. Its like the flick of a switch which turns your brain off for an hour or two. You feel fairly dopey and woozy afterwards where you may want to go and sleep it off.”
“Well, I DID IT !!!!!!!! … As I sat in the chair, I could feel my heart racing and remember telling the dentist that I needed to do this… I didn’t feel the IV being inserted, and as he was topping up the sedation level, he gave me the local injections, now this should be freaking me out, but honestly, I only felt a scratch!! and me being needle phobic too! And just to quell any fears about infection being present throughout extraction: The infection i’ve had on and off for months now came back with a vengeance last night, and I NEVER felt it being extracted. Next thing I knew I was in the little recovery room with my partner.”
“I had iv sedation last Friday and remember nothing about what happened. It was called ‘Twillight Sleep’. If i had known how well it worked i would have had it years ago! Felt absolutely fine afterwards although i am told i was quite confused! You need someone to accompany you and bring you home afterwards.”
“i had iv sedation back in june, got 2 rotten and abcessed teeth extracted and a filling to a front tooth – remember nothing at all from the iv going in, to being aware i was in my husbands car asking for some water and telling him how i felt nothing ”
“IV sedation is the best!! I would not hesitate to use it again if I needed to. They numb your hand first, then they put the IV in and before you know it you are off to sleepyland. I really don’t remember too much, just bits and pieces of conversations.”
“I had IV sedation when I got my wisdom teeth surgically removed yesterday. Let me tell you, it was AMAZING. Cannot put it in better words. All I remember is the doctor putting the sedative in the IV, feeling COMPLETELY relaxed, and still in control of everything, and closed my eyes and before I could reach 8 counting backwards, I was peacefully asleep. I woke literally 2 seconds later with no pain at all! I didn’t believe the doctor when he said it was all over.”
Is it still necessary to be numbed with local anaesthetic? Will my dentist numb my gums before or after I’m sedated?
The drugs which are usually used for IV sedation are not painkillers (although some pain-killing drugs are occasionally added, see below for more info), but anti-anxiety drugs. While they relax you and make you forget what happens, you will still need to be numbed.
If you have a fear of injections, you will not be numbed until the IV sedation has fully kicked in. If you have a phobia of needles, you will very probably be relaxed enough not to care by this stage. Your dentist will then wait until the local anaesthetic has taken effect (i. e. until you’re numb) before starting on any procedure.
“But how does the dentist know whether I’m numb?”
“You check the local anesthetic has worked by asking the patient. Just coz they’re sedated doesn’t mean they can’t answer you… in fact they better be able to answer or they ain’t sedated, they’re anaesthetised! If they’re not numb enough they’ll soon tell you. But they won’t remember telling you of course because of the amnesia effect…” (answer courtesy of Gordon Laurie, BDS – yet again!)
How is IV sedation given?
“Intravenous” means that the drug is put into a vein. An extremely thin needle is put into a vein close to the surface of the skin in either the arm or the back of your hand. This needle is wrapped up with a soft plastic tube. It makes the entry into the vein, then is slid out leaving the soft plastic tube in place. The drugs are put in through that tube (which is correctly referred to as an “indwelling catheter”, but more commonly known by the tradename of Venflon). The tube stays in place throughout the procedure.
The venflon to the right is a pinkie, which is one size bigger than the blue one that’s usually used for IV sedation in dentistry.
Throughout the procedure, your pulse and oxygen levels are measured using a “pulse oximeter”. This gadget clips onto a finger or an earlobe and measures pulse and oxygen saturation. It gives a useful early warning sign if you’re getting too low on oxygen, although if your dentist and the nurses are paying attention they should see it way before the machine does . Blood pressure before and after the procedure should be checked with a blood pressure measuring machine (a tongue-twister called “sphygmomanometer”, which for obvious reasons is referred to as “sphyg”).
But I’m terrified of all needles, not just dental injections!
You can get Ametop numbing cream to make the site where the needle goes profoundly numb:
“AMETOP numbing cream. I have a mortal fear of needles, and I find injections unbearable. Every injection I’ve had in my life has been intolerable. However, my dentist managed to get the IV in without me even noticing. I actually just turned round and it was in. The stuff is that good. I did not even feel any pressure. You can get a tube of it from your pharmacist for a few pounds, and it needs to stay in the fridge. If you need proof, buy two tubes, and use one a couple of days before your operation, just to reassure yourself how deeply numb it makes you.”
Ask your dentist or oral surgeon where the venflon will be going beforehand, and try it out! If you cannot get hold of Ametop, try EMLA cream.
You may also be offered laughing gas to enable you to accept the IV sedation.
What drugs are used? Are there different types of IV sedation?
Good question!! The most commonly used drugs for IV sedation are benzodiazepines, or “benzos” for short. These are anti-anxiety sedative drugs. In the UK, a benzodiazepine is almost always the only drug used for IV sedation (although I have heard of fentanyl being used as well). However, the situation is different in the U.S. First of all, regardless of location, what are the drugs which can be used for IV sedation?
1) Anti-anxiety sedatives (benzodiazepines): Midazolam and Diazepam
Mostly the drug used for IV sedation is a short acting benzodiazepine, or “benzo” for short. This is an anti-anxiety sedative. IV administered benzos have 3 main effects: they reduce anxiety/relax you, they make you sleepy, and they produce partial or total amnesia (i. e. make you forget what happened during some or, less frequently, all of the procedure). Total amnesia is more common with midazolam compared to diazepam.
By far the most commonly used drug for IV sedation is Midazolam, but occasionally Diazepam can be used.
Midazolam is the first choice because of its relatively short duration of action (meaning that it’ll be out of your system faster). Valium is (marginally) cheaper but longer acting and a bit “harder” on the veins, so you may feel a burning sensation on your arm/hand when the drug first enters. Local anaesthetic solution can be mixed in with Diazepam to make things more comfortable. The latest IV Diazepam is an emulsion which is claimed to be easier on the veins.
The drug is put into the vein at the rate of 1mg per minute for Diazepam or 1 mg every 2 minutes (followed by an extra 2 minutes to evaluate the effect) for Midazolam (because Midazolam is stronger in terms of the dose needed to achieve sedation). Because there are differences between individuals in how much of the drug you need to be sedated, your response to the drug is monitored. Once the desired level of sedation is achieved, the drug is stopped.
The Venflon is left in place during the procedure so that the sedation can either be topped up or so that the reversal agent for benzos (Flumazenil) can be put in in the unlikely event of an emergency.
Opioids (strong pain-killers) can be used as an add-on to either benzodiazepines or barbiturates.
At first glance, the use of opioids seems appealing, because of the pain-killing factor. In reality, this usually only comes into play for post-treatment pain, because local anaesthesia will take care of any pain during treatment. However, should the local anesthetic effect begin to lessen, an opioid will help to alter the experience of pain.
What is often done instead is give a long-acting local anaesthetic where post-op pain is expected. When you take opioids, even terrible pain becomes tolerable – you can still feel the pain, but somehow you don’t care. Also, where barbiturates are used (see below), an opioid must be added to counteract their pain-threshold-lowering properties.
The addition of an opioid may also be desirable if a benzo has been administered to its maximum recommended dose yet the patient remains unsedated (which is more likely if you’ve been using benzodiazepines for years and have become tolerant to them). In this case, adding an opioid may provide the desired sedation. Alternatively, propofol (see below) may be used.
Opioids which may be used for IV sedation include:
- Meperidine (Demerol)
- Butorphanol (Stadol)
- Nalbuphine (Nubain)
- Fentanyl (Sublimaze)
- Pentazocine (Talwin)
Barbiturates (sleep-inducing drugs) are not used for conscious sedation in the U.K., and have gone out of fashion in the U.S. The only barbiturate which is still occasionally used is called Pentobarbital Sodium (tradename: Nembutal).
In the absence of a trained anesthesiologist, barbiturates are pretty dangerous to use, for a number of reasons: it’s very easy to have the patient slip into general anaesthesia by mistake, where breathing and heart rate are dangerously lowered and coma and death can follow. Worse still, unlike for benzos, there’s no reversal agent. Barbiturates have only one advantage over benzos, and that is that they can be used to provide very long periods of conscious sedation. If pentobarbital is used, it’s in combination with opioids (see above), because barbiturates have the effect of lowering a person’s pain threshold.
Some anaesthetists use Propofol instead of benzodiazepines. The advantage of this is the very rapid recovery time, less than 5 minutes. The drug must be continuously administered, so the drug is pumped in using an electric infusion pump, the dose rate is set by the anaesthetist. Propofol is not a common sedative agent because it’s very easy to tip over into GA (General Anaesthesia) with it, where reflexes such as breathing are lost. It can be useful you have developed a high tolerance to benzodiazepines because you’ve been hitting them hard for years. Propofol is classed as a GA drug and in the U.K. can only be administered in a hospital setting (although a few private dental clinics meet the standard of a hospital setting, and offer it as well).
Anything else? And why so many different drugs?
There are quite a few other drugs that can be used for IV sedation. But in practical terms, most of the time a single benzodiazepine, usually midazolam, is used. This is especially true in the UK, where polydrug use is discouraged (even though it is not illegal). A typical IV session takes up to 1 1/2 hours. If it takes longer, it’s done in multiple visits, or depending on the case, under General Anaesthesia.
In the U.S., the situation is slightly more complex. Polydrug use is much more common, possibly because IV sedation is taught at a high level. This encourages the use of polypharmacy (multiple drugs). Also, there appears to be a liking for long IV sessions, which require the use of polypharmacy. Long IV sessions may be driven by consumer demand, or maybe it’s a training issue.
Many IV specialists in the United States are opposed to the use of opioids for sedation, but there is a habit of using them ingrained in most practitioners. However, things appear to be changing as new dentists are coming through.
The general consensus among the leading experts in the field of dental sedation today is: the fewer medications are used, the safer the treatment tends to be (and the easier it is to track any potential problems). Usually, this means one medication only. Midazolam tends to be the drug of choice.
Is it safe? Are there any contraindications?
IV sedation is extremely safe when carried out under the supervision of a specially-trained dentist. Purely statistically speaking, it’s even safer than local anaesthetic on its own!
However, contraindications include
- known allergy to benzodiazepines
- alcohol intoxication
- CNS depression, and
- some instances of glaucoma.
Cautions (relative contraindications) include psychosis, impaired lung or kidney or liver function, advanced age, and sleep apnea. Many people who have sleep apnea haven’t been officially diagnosed – if you are overweight and you snore, do mention this.
Heart disease is generally not a contraindication.
If you have been taking benzodiazepines for many years, your tolerance may be very high – so let your dentist know that you’ve been taking them!
The Dental Sedation Teachers Group uses the following classification for making the decision if and where conscious sedation should be provided:
- I – Normal, healthy patient
- II – A Patient with mild systemic disease, e.g. well controlled diabetes or epilepsy, mild asthma
- III – A patient with severe systemic disease limiting activity but not incapacitating, e. g. epilepsy with frequent fitting, uncontrolled high blood pressure, recent heart attack
- IV – A patient (usually hospitalised or bedridden) with incapacitating disease that is a constant threat to life
- V – A patient who is expected to die within 24 hours with or without treatment
source: American Society of Anaesthesiology Classification of Physical Status (ASA)
If you are in category I or II, then you can normally be treated in a general practice.
If you are in category III, it is best to be treated in an environment where more experienced support is available (a hospital-based clinic or a sedation clinic where medical support is available).
What are the main advantages of IV sedation?
- IV sedation tends to be the method of choice if you don’t want to be aware of the procedure – you “don’t want to know”. The alternative in the U.S. is oral sedation using Halcion, but oral sedation is not as reliably effective as IV sedation.
- The onset of action is very rapid, and drug dosage and level of sedation can be tailored to meet the individual’s needs. This is a huge advantage compared to oral sedation, where the effects can be very unreliable. IV sedation, on the other hand, is both highly effective and highly reliable.
- The maximum level of sedation which can be reached with IV is deeper than with oral or inhalation sedation.
- Benzodiazepines produce amnesia for the procedure.
- The gag reflex is hugely diminished – people receiving IV sedation rarely experience difficulties with gagging. However, if minimizing a severe gag reflex is the main objective, inhalation sedation is usually tried first. Only if that fails to diminish the gag reflex should IV sedation be used for this purpose.
- Unlike General Anaesthesia or Deep Sedation, conscious IV sedation doesn’t really introduce any compromises per se in terms of carrying out the actual procedures, because people are conscious and they can cooperate with instructions, and there is no airway tube involved.
Are there any disadvantages?
- It is possible to experience complications at the site where the needle entered, for example hematoma (a localized swelling filled with blood).
- While IV sedation is desired precisely because of the amnesia effect (i. e. forgetting what happened while under the influence of the drug/s), there can be a downside to this: if you can’t remember that the procedure wasn’t uncomfortable or threatening, you cannot unlearn your fears. However, it depends on the precise nature of your phobia and the underlying causes to which extent this may be a problem. Some people would voice a concern that some patients can’t be “weaned off” IV sedation, as dental anxiety tends to returns to baseline levels. As a result, people who rely on IV sedation may be less likely to seek regular dental care. Other people would argue that this is not a concern if IV sedation is readily available to people.
- Some dentists may resort to IV sedation too quickly. Sedation should not be used as a substitute for TLC and behavioural techniques, but as an additional tool if these alone don’t work, or if it is a potentially traumatic procedure. You should want sedation, rather than feeling forced into it because your dentist is unwilling to explore other ways of helping you.
- Recovery from IV administered drugs is not complete at the end of dental treatment. You need to be escorted by a responsible adult.
- Cost is another disadvantage – IV sedation is more expensive than other sedation options.
Can I take valium tablets or other benzodiazepines beforehand?
Yes. You must let your dentist know about it though (unless your dentist has prescribed them and knows already). It’s best to do this before you turn up on the day, because you’re likely to forget to mention it.
What about eating and drinking before sedation?
Some dentists in the U.K. prefer to have people have a light meal about an hour before they come in (this is for conscious sedation using midazolam), but it may depend on the drugs used for the IV. In the U.S., the standard advice appears to be no eating or drinking for 8 hours beforehand. Where a GA drug like propofol or ketamine or a barbiturate is used, there is a danger that a person who regurgitates food while anesthetized could get food or liquid into their lungs.
After IV Sedation:
- Have your escort take you home and rest for the remainder of the day.
- Have an adult stay with you until you’re fully alert.
- Don’t perform any strenuous or hazardous activities and don’t drive a motor vehicle for the rest of the day.
- Don’t eat a heavy meal immediately. If you’re hungry, eat something light, e. g. liquids and toast.
- If you experience nausea, lie down for a while or drink a glass of coke.
- Don’t drink alcohol or take medications for the rest of the day unless you’ve contacted your dentist first.
- Take medications as directed by your dentist.
- If you have any unusual problems, call your dentist.
Sedation: A Guide to Patient Management 5th Edition (2009) by Stanley Malamed – A pretty comprehensive text written for dentists, but the layout is rather confusing and the text is difficult to understand for the layperson. Targeted at the U.S. market.
Clinical Sedation in Dentistry (2009) by Girdler, Hill and Wilson – “a comprehensive textbook on the principles and practice of clinical sedation in dentistry, written by experienced educators and internationally renowned researchers in the field”. Haven’t had a look at it myself, but looks like a much easier read judging from the Amazon preview. Appears to be aimed at the U.K. market.