Inhalation Sedation (Laughing Gas)
Inhalation sedation, laughing gas, relative analgesia, RA, happy gas, gas, nitrous, nitrous oxide, N2O-O2… this one has more names than any other sedation technique! And deservedly so. Inhalation sedation with nitrous oxide (N2O) and oxygen (O2) has been described as “representing the most nearly ‘ideal’ clinical sedative circumstance”…
How is nitrous oxide administered?
The equipment used for delivering “happy gas” is quite simple. It consists of a supply of compressed gases and an apparatus which delivers the gases to the client. By turning some knobs and flipping on/off switches, the administrator can produce the desired mix of N2O-O2 in the desired quantities. Flowmeters and pressure gauges allow the administrator to keep an eye on the flow of gases.
The desired N2O-O2 mix is fed through a tube to which a nasal hood or cannula is attached. This hood is put over your nose. All you have to do now is breathe normally through your nose – bingo!
In modern machines there is a sort of double mask (see photo) where the outside mask is connected to a vacuum machine to suck away the waste gas – you wouldn’t want your dentist to get a face full of N2O… The white inside mask, which is placed over your nose, comes in lots of yummy scents.
The twin tubes running to the mask are for “gas in” and “gas out”. The “gas out” line is attached to the vacuum machine, while the “gas in” line is attached to the RA (short for relative analgesia) machine. The inner mask is attached to the “line in”, you breathe out through a one-way valve in the inner mask, and the exhaust gas is collected inside the outer mask and sucked into the vacuum machine.
IV (Intravenous) Sedation
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.
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, and 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 trade name 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”).
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