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. The needle 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.
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 dangerously
low on oxygen, although if your dentist and the nurses are paying attention
they should see it before the machine does =). The warning signs are
unresponsiveness and slow breathing. 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").
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 US, for reasons which I'll try and outline below. First of all, regardless
of location, what are the drugs which CAN be used for IV sedation?
1) Anti-anxiety sedatives ("benzos"): 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 - see the Oral
Sedation page for more info on benzos in general. 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 (see below).
By far the most commonly used drug for IV sedation is Midazolam (tradenames:
Versed in the US, Hypnovel or Dormicum in the UK), but occasionally Diazepam
(tradename: Valium) 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.
Barbiturates (sleep-inducing drugs) are not used for conscious sedation
in the UK, and have gone out of fashion in the US. The only barbiturate
which is still occasionally used is called Pentobarbital Sodium (tradename:
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 more than 1 1/2 hours
of conscious sedation (which is about the max with benzos). If pentobarbital is
used, it's in combination with opioids (see below), because barbiturates have
the effect of lowering a person's pain threshold.
Opioids (strong pain-killers) can be used as an add-on to
either benzos (for procedures up to about 1 1/2 hours) or barbiturates (for
procedures longer than 2 hours).
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. However, what is often
done instead is give a long-acting local anaesthetic where post-op pain is
expected. When you take opioids, even excruciating pain becomes tolerable - you
can still feel the pain, but somehow you don't care (I've tried it!). Also, where
barbiturates are used, an opioid must be added to counteract their
Opioids are always used in the so-called Jorgensen technique (which in
its basic form involves pentobarbital, an opioid, and an anticholinergic)
sometimes used in the US for procedures taking 2 hours or more.
The addition of an opioid may also be desirable if a benzo has been
administered to its maximal recommended dose yet the patient remains unsedated
(which is more likely if you've been hitting the valium hard for years). 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)
Some anaesthetists use Propofol instead of benzos. The
advantage of this is the very rapid recovery time, less than 5 mins. The
disadvantage is 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 with it (where reflexes such as breathing are lost). It can be
useful if a person is "immune" to benzos because they've been hitting
them hard for years.
There are quite a few other drugs that CAN be used for IV sedation. But
in practical terms, most of the time a single benzo, 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 US, the situation is slightly more complex. Polydrug use appears
to be 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 (I don't know).
Many US IV specialists 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.