Inhalation Sedation Flashcards
What are the aims of inhalation sedation?
Anxiolysis (reduces fear/anxiety) & analgesia (reduce pain)
Also to improve cooperation
What does Anxiolysis mean?
Reduce fear/anxiety
What does analgesia mean?
Reduces pain
How much heavier than air is nitrous oxide?
1.5
What coloured cylinders is nitrous oxide supplied in?
Blue
What size do nitrous oxide cylinders come in?
Size E
What pressure is nitrous oxide stored a liquid under?
44bar or750PSI
What are the properties of Nitrous Oxide?
Colourless and virtually odourless
How heavy is a full cylinder of Nitrous Oxide?
20lbs
How much Nitrous Oxide is needed to produce unconsciousness?
70%
What coloured cylinders is Oxygen supplied in?
Black with a white shoulder / by 2025 they will all covert to white bodies and carry the name oxygen on them
What pressure is oxygen stored a liquid under?
137bar or 2000 psi
What does MAC stand for?
minimum alveolar concentration
When referring to gases what does MAC relate to?
Potency (strength)
What is the time weighted average (TWA) for staff working with nitrous oxide?
100ppm over an 8 hour time period.
What does a half full nitrous oxide cylinder contain?
Gas above a liquid
What does a full oxygen cylinder contain?
Gas
Who has the legal responsibility for checking the inhalation sedation machine?
The treating clinician
Gases used for sedation have a relatively high MAC. What is it?
105
The MAC being “high” means that nitrous oxide is?
A weak anesthetic
Why is it virtually impossible to produce anaesthesia using nitrous oxide alone in a patient who is adequately oxygenated?
The MAC is over 80
At what concentration of nitrous oxide is plane 1 obtained?
5-25%
What is the seal called on the oxygen cylinder?
Bodok seal
At what concentration of nitrous oxide is plane 2 obtained?
20-55%
At what concentration of nitrous oxide is plane 3 obtained?
Above 50%
What is plane 1 of analgesia?
Moderate sedation and analgesia
Relaxation
Tingling in fingers, toes n cheeks
Warmth
Alert and responsive
Pulse/Bp will be normal
What is plane 2 of analgesia?
Dissociation sedation and analgesia
Relaxation/ sleepiness
Possible dreaming
Delayed response to questioning
What is plane 3 of analgesia?
Total analgesia
Marked sleepiness and glazed appearance
Nausea and dizziness
Vomiting
Unresponsive to questioning
What is sickle cell disease?
Blood disease, abnormal form of hemoglobin
What does inhalation sedation improve?
Gagging
In what trimester can inhalation sedation not be used?
1st trimester
What is the rapid onset of inhalation sedation?
2-3 minutes - peak: 3-5
What is the rapid recovery of inhalation sedation?
3-5 minutes
Are electromechanical monitoring mandatory for inhalation sedation?
No
Contraindications of inhalation sedation?
Nasal obstruction
Claustrophobic patients
ASA 3+
Muscle wasting disease (myasthenia Gravis /multiple sclerosis)
Indications of inhalation sedation?
Anxiety
Needle phobia
Pain control
Allergic to IV agents
Gagging
Pt at risks of respiratory depression - asthma/Sickle cell anaemia
Why do Sickle cell anaemia and asthma patients benefit from IHS other than IV sedation?
Benefit from a guaranteed oxygen level of at least 30%
What is sickle cell anaemia?
Lack of oxygen in the haemoglobin
Why would an asthma patient be more likely to have ihs instead of IV?
To avoid respiratory depressive effect. And they will benefit from increased level of oxygen
Why would somebody who is diabetic benefit from IHS more than GA?
GA has longer period of starvation
Why would somebody with kidney/ liver disease be treated with RA rather than IV or GA?
Drug is not metabolised in the liver
Why would somebody with cerebral palsy benefit from IHS?
Reduces involuntary movements
What does PSI stand for?
Pound per square inch
What is the quantiflex MDM head?
The inhalation machine
What on the RA machine is used to titrate the nitrous oxide?
the mixture dial
What is the tube on the left of the RA machine showing?
N20
What controls the flow rate?
Flow control valve
What is the tube on the right of the RA machine showing?
O2
How can you inflate the bag without setting the flow rate?
o2 flush button
How can you check the reservoir bag has no holes?
Cover the non-rebreathing check valve with hand and inflate bag with o2 flush button.
Inspect the bag
How often should the bodok seal be changed?
2 years
What are the safety checks on the RA machine?
Oxygen fail safe
oxygen flush
Reservoir bag
Minimum oxygen 30%
Check inlet valve isn’t blocked
what is the Air entrainment valve ?
Would operate if the patient was in spontaneous respiration and there was an obstruction in the fresh gas to the patient
What is the scavenging system?
Vacuum suction
How should Size C, D and E cylinders be stored?
Horizontally on shelves
How should Size F, G and J cylinders be stored?
Vertically on concrete floor pens
Does Nitrous oxide bind to components of the blood like oxygen?
No it is carried in the blood
Whys is there a rapid recovery from nitrous oxide?
It has a poor solubility
What is diffusion hypoxia?
Due to the sudden reversal of concentration gradients in the lungs following the discontinuation of nitrous oxide, leading to a decrease in oxygen levels in the bloodstream
How can we avoid diffusion hypoxia?
Give 2 minutes of oxygen after tx is finished
How long does it take for the patient to feel the initial effect of nitrous oxide?
after 20 seconds
How long does it take for the patient to feel the full effect of nitrous oxide?
3-5 mins
Where does the nitrous oxide is inhaled, where does it travel to?
Alveoli sacs within the lungs
When Nitrous oxide is introduced to the body, how does it get into the blood?
It diffuses through the alveolar membrane into the blood