GA Flashcards
What is GA
- Any technique using equipment or drugs which produces a loss of consciousness in specific situations associated with medical or surgical interventions
- Loss of consciousness or abolition of protective reflexes
How do anesthetic agents produce anaesthesia
by depressing specific areas in the brain
How do inhaled agents reach the CNS
• Inhaled agents enter through the lungs distributed to tissues by the circulation, reach specific sites in the CNS by crossing the blood brain barrier. The magnitude of CNS depression is proportional to partial pressure as they reach the CNS
How do IV agents reach the CNS
• IV agents are given straight into circulation, distributed through the body and reach specific sites in the CNS by crossing the blood brain barrier
Describe a child’s anatomy
○ Large head, short neck, large tongue
○ Narrow nasal passages
○ Are obligate nasal breathers at birth
○ High anterior larynx
○ Larynx narrowest at cricoid cartilage
Large floppy epiglottis
Describe a child’s respiratory physiology
○ low functional residual capacity
○ Closing volume is greater than functional residual capacity up to 5 years of age, leading to an increased ventilation/perfusion mismatch
○ Horizontal ribs, weak intercostals muscles leading to relatively fixed tidal volume
Oxygen consumption is high 6ml/kg/min compared to 3ml/kg/min in adults
Describe a child’s temperature regulation
○ High surface area to body weight ratio
○ Large head surface area and heat loss
○ Require a higher temperature for a thermoneutral environment
○ Immature responses to hypothermia (poor shivering and vasoconstriction)
Brown fat metabolism (adults have less brown fat) which increases oxygen consumption
Describe a child’s nervous system
○ Increased incidence of periodic breathing and apnoea’s (breathing isn’t as regular and they hold their breath more)
○ Ventilatory response to CO2 is more readily depressed by opiates
Immature neuromuscular junction leads to increased sensitivity to muscle relaxant
What are the common inhaled agents
- Inhaled agents: nitrous oxide, sevoflurane (agent of choice for induction), halothane, isoflurane, desflurane
What are the common IV agents
propofol (used for induction and in some situations for maintenance)
How does the anesthetist decide on what drugs they will use
○ Depends on § Length and type of procedure § Patient preferences for induction § Medical history § Previous GA experience § Anaesthetists recommendations § Equipment § Staff § Other resources
What are the types of airway for GA
laryngeal airway mask
nasal endotracheal intubation
oral endotracheal intubation
Which airway requires a throat pack
all do
What is a throat pack
a throat pack is gauze that you pack around the tube at the back of the mouth away from where you are working to catch saliva, material, blood etc to stop it going down the airway
What are the stages of anesthesia
○ Stage 1 is induction
○ Stage 2 is excitement
○ Stage 3 is surgical anaesthesia (what we want)
Stage 4 is respiratory paralysis (what we don’t want)
What do the GDC expect from dentists regarding GA
○ As a registered dental professional you could be held responsible for the actions of any member of your team who does not have to register with the GDC
○ Be competent in when, how and where to refer a patient for GA
Evaluate the risks and benefits of treatment under GA
What are indications for GA
- Child needs to be asleep for tx because they are too young, anxious, or too uncooperative to accept treatment any other way
- Dentist needs patient to be guaranteed to be completely still, operation is complex i.e the surgeon needs the child to be fully anaesthetised
What are GA contraindications
- Risks of procedure do not outweigh the benefits
- E.g for ortho extractions
What are the major risks for GA
○ Rare - 3 in a million
Can end up with brain damage or can die
MUST INFORM PARENTS OF THIS RISK
What are the minor risks from GA
○ Common ○ Pain ○ Headache ○ Nausea, vomiting ○ Sore throat ○ Sore nose/nose bleed ○ Drowsiness ○ Upset Increased anxiety about future dental treatment
What are the risks from dental treatment
§ Pain § Bleeding § Swelling § Bruising § Loss of space § Visible restorations § Restorations may be lost/fail/wear through Stitches
What are the complications for GA
○ Damage to mouth/oropharynx from intubation especially if it was difficult
○ Minor idiosyncratic/allergic reactions - nausea and vomiting
○ Malignant hyperpyrexia
○ Slow recovery from anaesthetic ○ Prolonged apnoea after muscle relaxant (suxamethonium) ○ 'awareness' - paralysed but not effective anaesthesia if it had muscle relaxant ○ Laryngospasm § Something irritates the airway causing it to spasm ○ Coughing/moving during procedure - anaesthetic is too light during stimulation e.g extractions Prolonged bleeding, intra-operative or bleeding post op
What is malignant hyperprexia
§ This is a reaction to inhaled anaesthetic agent so need IV induction and maintained with propofol
§ (rare! But VERY important to ask about FH problems or allergy to anaesthetic as it requires specific care - they go on a morning list when the machine has been rested so there are no inhaled agents)
Why must GA be justified
due to risk of mortality
What should be done when sharing airway
○ Need to ensure head and neck is positioned so not over extended
○ During dental treatment, especially extractions on the lower arch, the mandible can easily fall or be pushed backwards and the chin onto the chest which would obstruct the airway
The dentist must be aware of this and lift the mandible or anaesthetist/assistant may help to hold the mandible forward
What must be present incase of emergency
- Necessary to have space, facilities, equipment, appropriately trained personnel, if emergency arises and resuscitation is required
Agreed protocol to summon help and ensure timely transfer to specialist anaesthetic and medical care e.g PICU or high dependency
What is the WHO surgical safety checklist
○ Brief before list, debrief after
§ Before the GA the team can introduce themselves, discuss the px, check medical history, discuss how long it will take, can share concerns and opinions
§ Debrief consists of what went well and what didn’t
○ For every px every time
§ Sign in
§ Time out
§ Sign out
What are some medical conditions which require careful work up for GA
Sickle cell disease Down syndrome Bleeding disorder Cardiac condition Renal disease Diabetes Liver disease Cystic fibrosis Severe asthma Epilepsy
What is the discharge criteria for GA
○ Fully conscious, able to maintain clear airway, exhibits protective reflexes
○ Satisfactory oxygenation and respiration
○ DVS stable - no unexplained cardiac irregularities, no persistent bleeding, pulse and BP acceptable, adequate peripheral perfusion ○ Pain, nausea and vomiting controlled ○ Temperature in normal limits Eaten, drunk, been to toilet
What is satisfactory oxygenation and respiration
§ 2-5 YO = 24-30breaths a min
§ 5-12 YO = 20-24 breaths a min
What stable CVS
§ HR = 2-10 years mean 80 beats/min
BP for 1-10 years = 90 + 2xage in years
What are post op instructions
○ Pain control ○ Travel home ○ Rest/quiet play ○ Monitoring ○ What to look out for - pain, bleeding etc ○ Next day off school/nursery ○ Extraction advice ○ Soft diet ○ Prevention ○ Follow up Discharge letters
Who makes initial decision that GA is required
dentist but may change at assessment visit
What should be explained to parents when getting consent
- Explanation of risks and benefits of GA and all alternative options (prevention only, biological caries management, LA +/- IS, IV, doing nothing)
- Explanation of how different treatment modalities might affect the treatment plan - GA treatment plan is more radical and reliable and clear prognostic outcomes (i.e you should be confident the plan will last at least 5 years without child having pain)
Advise that 1st appointment will be for treatment planning ONLY and that plan may change with a specialist opinion
- Explanation of how different treatment modalities might affect the treatment plan - GA treatment plan is more radical and reliable and clear prognostic outcomes (i.e you should be confident the plan will last at least 5 years without child having pain)
Who can consent
mother
father sometimes
adoptive parents
married step parents if they have acquired parental responsibility
legally appointed guardian
person with a residence order concerning the child
local authority that is designated to care for the child
local authority or person with an emergency protection order for the child
if no legal guardian then social services will need to be involved
do foster parents and kinship carers have automatic parental responsibility?
no
when can fathers consent
if married to mother at time of child’s birth (Eng/ W/NI), conception (Scot) or subsequently
- Unmarried father if named on birth certificate, 04/05/2006 Scot
Unmarried father whose child registered before these dates OR if not mentioned on birth certificate DOES NOT automatically have parental responsibility
but may acquire by court
When can a child consent to their own treatment
onsent to medical treatment can be given by a child under the age of 16 if ‘Gillick competent’
○ children under the age of 16 can consent to medical treatment if they have sufficient maturity and judgement to enable them fully to understand what is proposed. (Gillick vs West Norfolk and Wisbech AHA & DHSS in 1985)
When should first stage of consent be done
should ideally be done on a separate day before the operation to give parents and child time to fully understand all risks, benefits and alternatives
What is the pre-op info
○ Fasting
§ As reflexes are lost so anything in the stomach can come up and go into the lungs resulting in aspiration pneumonia
○ Proposed treatment
○ GA procedure
○ Adult escort with no children, post op arrangements, post op care and pain control
What type of consent is a must for GA
written
What should the referral letter state
○ Patient name ○ Patient address ○ Patient/ Parent contact numbers- landline and mobile ○ Patient medical history ○ Patient GP details ○ Parental responsibility ○ Justification for GA ○ Proposed treatment plan Previous treatment details
What MUST a referral letter include
Recent radiographs or if not available explanation of why (e.g. I have attempted to take bitewings/ periapicals but the patient is uncooperative)
