Pharma Behaviour_Nitrous Sedation Flashcards
What are the goals of nitrous sedation?
- Facilitate appropriate care of patient
- Decrease extremes of disruptive behavior
- Decrease anxiety
- Create a safer environment for patients/staff
- Bring the patient back to a psychological state which is safe for discharge
What are the indications for use of nitrous sedation?
-Patients mildly to moderately anxious
- Fear of needles
- Gag reflex
- Profound LA can’t be obtained
- Older children with previous negative dental experience
- Child with special needs
- Complex or long procedures
- Patient needs to be medically fit
What are the pharmocodynamics of nitrous oxide sedation?
(Effect of drug on body)
- Unknown mechanism (thought to act on GABAA or opioid receptors)
- Results in chlorine influx and hyperpolarisation of neurons
- Thus require greater stimulation for action potential to be generated
What is are the pharmacokinetics of nitrous oxide?
(Effect of body on drug)
-Rapidly absorbed through alveoli and carried by serum throughout circulation via partial pressure gradient
- Insolubility of nitrous oxide means equilibrium can be achieved quickly/blood brain barrier crossed
- Insolubility also means N2O leaves bloodstream quickly and passes into other tissues
- Diffuses into closed air spaces such as middle air until equilibrium achieved
- Little to no biotransformation
- Not metabolised by liver
- 99% eliminated through lungs (diffuse from CNS into bloodstream and exhaled from lungs)
- 0.04% metabolised by GIT
- Small amounts excreted
- Rapid and repeat recovery after cessation
At what time after inhalation can the peak effects be expected?
3-5minutes
What are the physical impacts of nitrous oxide?
CNS:
- euphoric and depressant effects
- Pt should be relaxed and comfortable + acknowledge reduced fear
- Pt should be aware of surroundings
- Pt should be able to respond to instructions and converse
- Pt should be happy/in pleasant mood
- pharyngeal and laryngeal reflexes maintained
Vital signs:
-Remain normal
Body movements:
- Relaxation (shoulders drop, legs uncrossed, feet relaxed, etc.)
- Deeper inhalation
- Eyes initially alert, but lessen with sedation and blink rate slower
- Facial expression flat, may smile easier, no signs of tension
Patient’s feelings:
- Tingling in extremeities (not with all patients)
- Heaviness in thighs and legs
- Patient’s voice may resonate or carry hypernasal tone
- Operator’s voice may sound distant
- May feel warmth from vasodilation (but should be comfortable)
What are the contraindications for RA?
- Respiratory problems (COPD, asthma, cold, tonsilitis, nasal blockage, refusal to breathe through nose)
- GI bowel obstructin
- Cystic fibrosis
- Otitis media or other middle ear problems
- Psychiatric disease (e.g. drug adddiction)
- Pregnancy (1st trimester)
- Fear of nasal hood or claustrophobia
What are some adverse effects of RA?
Usually due to overdose or poor patient vomitting
- Nausea and/or vomitting
- Sleep
- Visual disturbance, room spinning
- Excessive laughing/crying
- Sweating
What are some signs of over-sedation?
- Nausea and/or vomitting, dizziness, lightheadedness
- Sleep
- Visual disturbance, room spinning
- Excessive laughing/crying
- Sweating
- Detachment/dissociation from environment
- Inability to move, communicate, keep mouth open
- Dreaming hallucination or fantasizing
- Out of body experience (Floating and/or flying)
- Humming or vibrating sounds
- Keep close eye on patient
- Uncomfortable body warmth
How should N2O be induced?
- Slowly
- Begin with 100% O2, increase N2O concentration by 10% per minute until desiered effect
- Elder patients (vomit easier)
Quick
- INtroduced to 40% N2O
- Monitor 2-3 minutes
- Titrate accordingly
- Better for younger children but increased risk adverse effect
What should be done if signs of overdose are evident?
- Reduce concentration
- Turn O2 to 100% if patient seleeps
- Avoid sudden changes/fluctuations
- Monitor patient closely
What are some precautions that shoudl be taken with RA?
- Appropriate training of those involved
- Do not leave patient unattended
- Two staff members always present
- Occupational health and safety
What are the components of equpiment used for RA?
- Gas delivery machine
- Inflatable bag
- Conducting tube
- Nasal hood
- Scavenging system
- Oxygen flush valve
(Air flows through the machine in this order, except for oxygen flush valve. Flows from scavenging system into high speed suction)
What is the flow rate of the delivery machine?
-2.5L/minute minimum
T/F the numbers on the flowmetre shows %
Flase
It shows litres of flow per minute
