Inhalation Sedation in Dentistry

I've recently been appointed as an accredited inhalation sedation trainer by the Royal College of Surgeons....but what is inhalation sedation?



What is Inhalation Sedation?


Inhalation sedation is one of the main sedation modalities used in dentistry, commonly used in both adults and children. Nitrous oxide is delivered in a mixture with oxygen via a nasal hood continuously during dental treatment. This is why this technique is often called gas (nitrous oxide) and air (oxygen). Other terminologies include happy air, relative analgesia, happy gas, laughing gas.

Nitrous oxide is an excellent adjunct for many because of its properties:
  • Anxiolytic
  • It is highly insoluble in blood
  • High MAC value of 110% i.e. you need to deliver 110% of nitrous oxide to a patient to deliver a general anaesthetic
  • Weak analgesic

Which Patient Groups can it Help?

Because of the above properties, this technique can be useful for:
  • Anxious adults
  • Anxious/young children
  • Patients with hypersensitive gag reflexes
  • Alternative for patients who might request IV sedation, but are contra-indicated for this e.g. respiratory diseases, 2nd trimester of pregnancy and beyond

Contra-indications for Inhalation Sedation:

  • Recent eye surgery
  • First trimester of pregnancy
  • Myasthenia Gravis
  • Nose blockages/abnormal anatomy that prevent either fitting of mask or nose breathing
  • Patients who are claustrophobic or can't tolerate wearing the nasal hood
  • Severe mental health issues e.g. schizophrenia
  • Severe respiratory issues e.g. COPD

What is the Technique?

The mixture of gases is delivered by the nasal hood pictured above, via machines such as the MDM Quantiflex, or Accutron Digital Ultra. The amount of nitrous oxide is titrated against the patient's response as follows:

  1. 100% oxygen, usually set to 6 L/min, but this can be adjusted depending on lung capacity
  2. Check the reservoir bag is moving, and isn't going flat 
  3. Once happy, start titrating the nitrous oxide up, initially 10% increments every minute
  4. Once up to 20%, then increase at 5% increments until the endpoint
  5. The maximum of nitrous oxide you can give on the machines is 70% nitrous oxide
  6. After treatment, give 100% oxygen for 2 minutes to prevent diffusion hypoxia 

Endpoint signs include: 
  • Relaxed
  • Eyelids drooping
  • Patient reporting tingling at extremities
  • Feeling heavy or floaty
  • Giggling
  • Patient allows you to do treatment

Signs of over sedation include:
  • Mouth not opening
  • Excessive laughing
  • Disorientation
  • Spontaneous mouth breathing
  • Loss of responsiveness/consciousness
  • Touching face or trying to pull off mask
  • Nausea/vomiting

How do you get Trained to do Inhalation Sedation?


To do any form of sedation in dentistry, you need to be appropriately trained as per the IACSD guidelines - see previous blog post about this here.

You need to have completed accredited training in inhalation sedation and well as having 10 signed off supervised clinical cases to do this technique independently. Courses can be:

  • Training during a deanery post e.g. DCT or StR posts
  • Accredited in house training in your trust - many CDS or hospital services are accredited
  • Completing a private accredited course - see here for the list
You also will have to complete 12 hours of sedation CPD per 5 year cycle, as well as yearly updates in ILS and PILS to offer IHS. 


As I have mentioned, I can now offer accredited training for those of you who wish to start offering this treatment modality to patients. To find out more contact me




What are your experiences of using inhalation sedation? Please leave them in the comments below.



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