•Analgesic gas for moderate to severe pain / Labour Pain.
•Analgesic A pain relieving drug
•Analgesia A deadening or lack of pain without
a loss of consciousness.
•Indications: Entonox is for moderate
to severe pain / Labour pains
•Colour: Blue with white quarters
on the cylinder neck.
•Capacity: 660 litres
•Composition: 50% Nitrous Oxide, 50% Oxygen
••Hazard Labels: Compressed Gas. Oxidising Agent (breaks-down).
Care of Equipment entonox
•Storage: Well-ventilated area.
Away from combustible
•Do not lubricate cylinders and valve
assemblies with oil or
•Store cylinders horizontally.
•Avoid exposure to temperatures less than -5oC, the gases will separate. If this occurs invert the cylinder several times to mix the gases.
Advantages of Entonox
•Rapid therapeutic effects (3-5 minutes). May take
5-10 minutes before maximum effect achieved.
•Therapeutic effects wear off quickly – symptoms are not masked during examination at hospital.
•Minimal side effects.
•Does not depress respiratory or cardiac function.
•Self-administered (by patient).
•No dosage requirement.
•Facilitates patient handling and transportation
•Provides a high concentration of oxygen.
•Bends – (decompression sickness or Caissons disease)* - anyone diving within the last 24
hours should be considered a risk.
•Severe head injuries [with impaired consciousness] (may mask signs and symptoms of the injury)
•Violently disturbed psychiatric patients (difficult to administer).
•Penetrating Torso Injury
•Polytrauma involving Chest or Abdomen
•Oxygen >50% is required
•Alcohol or drug intoxication – where self-administration may not be understood (potential interaction between gas and drug/alcohol).
••Young children and those unable to understand self-administration.
•Explain the purpose - pain relief.
•Explain the likely effects:
–Drowsiness and/or dizziness.
–Feeling of intoxication.
–Effects wear off quickly.
–Unlikely to ‘knock-you-out’.
•Ensure the patient’s respiratory function is sufficient to operate the demand valve.
•Instruct the patient in the use of the equipment:
•–The mouthpiece is the 1st choice of administration currently; however, if using a mask ensure an airtight seal between the face and the mask
Take normal to deep breaths
•–Record the administration of Entonox on the patient report form and report it to the receiving hospital
Entonox can be given to children provided they can understand the instruction involved.
How effective is it?
•Evaluate the pain before administration (OPQRST)
••Document the patients pain score
•Administer the analgesic
••Re-evaluate the pain score following administration
••Remember; Entonox is effective for moderate to severe pain