Human Disease Flashcards
When were GAs banned in GDPs?
2000
Name the 3 categories of pateints whom should recieve a GA?
- Situations where it would be impossible to achieve adequate local anaesthesia and complete treatment without pain
- Patients who, because of problems related to age/maturity or disability, are unlikely to allow safe completion of treatment
- Patients in whom long term dental phobia will be induced or prolonged
What is the definition of anaesthesia?
A reversible iatrogenic state characterised by unrousable unconciousness and reflex depression
Unarousable Unconsciousness - IV agents and gaseous agents?
IV:
- propofol
- thiopentone
- ketamine
Gaseous:
- volatile - isoflurane/sevoflurane/desflurane
- NO2
IV anaestehtics - aim? side effects? adverse affects?
Unconsicuosness
Sides:
- loss of airway reflexes
- stop breathing
- depress cardiac function
Adverse:
- death
Volatile anaestehtics - aim? side effects?
Unconsicuosness
Sides:
- loss of airway reflexes
- stop breathing
- depress cardiac function
What is the defintion of reflex depression?
Drugs which cause unconsciousness depress some reflexes
Larger doses of iv or volatile anaesthetic
- greater reflex depression
- more side effects
The degree of reflex depression required will depend on the surgery being performed
Decrease the noxious stimulus (input)
Local anaesthetic nerve block
Analgesic drugs
Decrease the response to stimulus (output)
Local anaesthetic nerve block
Neuromuscular junction (NMJ) blocking agents
Explain the process of a GA?
Preparation
- Fasting (6 hrs food, 2 hrs fluid)
- Consent
Induction
-IV or inhalation
Maintenance
- Volatile or continuous IV infusion propofol
- Reflex suppression
Emergence
- Reverse NMJ blockers
- Turn off anaesthetic agent
What is monitored during a GA?
Airway
- Facemask
+/- oropharyngeal/nasopharyngeal airway
- Laryngeal mask airway
- Endotracheal tube
Oral, nasal or tracheostomy
Breathing
- Spontaneous
- Intermittent Positive Pressure Ventilation
- Monitoring- SpO2, gas analysis
Circulation
- Monitoring -HR, BP, ECG
- IV access, fluids
The art of GA - what is included?
Tailoring the anaesthetic to
Patient
Surgery
Pre-operative assessment
Intra-operative care
Post-operative care
Communication
Non-technical skills
Why is dental GA more risky than general GAs?
Shared airway
- Competing for same space
- Airway soiling (blood/saliva)
- Laryngospasm
Anxious patients
- Mask/needle phobias
Significant co-morbidities
- Learning disability
Epilepsy/cardiac anomalies/airway/neck
- Blood borne diseases
Solutions to a shared airway?
Nasal mask - patient exhales at you
Laryngeal mask airway - takes up a lot of room in operative field
Nasal endotracheal tube - more technique sensitive and needs more drugs - higher risk for failure
Trachestomy - highest risk - but best outcome
Whom should recieve conscious sedation?
Should be considered in preference to GA
What is conscious sedation?
Patient remains conscious and is able to both understand and respond to verbal commands either alone or accompanied by a light tactile stimulus
Very difficult to achieve!
Easily becomes rousable but unconscious, and is a small step away from GA without airway control.
Requires equipment, training, assistance and close monitoring of patient and clear understanding of risks
Usually in combination with local anaesthesia
Drugs for conscious sedation? - Benzos, IVs and gaseous?
Benzodiazepines
- Oral temazepam/diazepam
- IV midazolam
- Transmucosal
Intravenous anaesthetic agents
- Propofol
Intravenous opiods
- Fentanyl
Gaseous
- Volatile anaesthetics
Isoflurane/sevoflurane/desflurane
- Nitrous oxide in oxygen
Antidotes for conscious sedation drugs - Benzos, Opiates? Propofol and NO?
Benzodiazepines
- Flumazenil
Opiates
- Naloxone
Propofol, ketamine
- No antidote
Nitrous oxide, volatile anaesthetics
- No antidote
Describe the process of conscious sedation?
Consent for treatment
- Children, Mental Capacity Act
Environment/equipment
- Pulse oximetry, BP
Team/ training
- Basic Life Support, critical incidents
Recovery, discharge, aftercare
Clinical governance/ audit/ incident reporting
Name the risks of conscious sedation
Oversedation
Loss of airway
Respiratory depression
Vomiting and aspiration
Idiosyncratic reactions
Delayed recovery
Describe the basic technqiues and process for conscious sedation?
IV midazolam
Inhalational with nitrous oxide/oxygen
Oral / transmucosal benzodiazepine
Only nitrous/oxygen is considered basic in children under 12
Require training
- Must have competence in IV techniques to perform ANY basic technique
Monitoring
- BP, pulse oximetry
Operator sedationist with dental nurse assistant
Describe the advanced technqiues and process for conscious sedation?
Any form of conscious sedation for patients under the age of 12 years (other than nitrous oxide/oxygen inhalation sedation)
Benzodiazepine + any other intravenous agent for example: opioid, propofol, ketamine
Propofol either alone or with any other agent for example: benzodiazepine, opioid, ketamine
Inhalational sedation using any agent other than nitrous oxide / oxygen alone
Combined (non-sequential) routes for example: intravenous + inhalational agent (except for the use of nitrous oxide / oxygen during cannulation)
Require a lot more training
Rescue
- Airway competencies (basic airway manoeuvres, airway adjuncts and the ability to administer positive pressure ventilation) are mandatory
Monitoring
- BP, pulse oximetry, capnography
Separate sedationist
Team must have “immediate access to the equivalent range of skills and facilities to be found in an NHS Acute Trust”
Advanced paediatric sedation
- Even more training
What was included in the Poswillo Report 1990?
Avoid general anaesthesia where possible
Same standards of monitoring, personnel and equipment should apply whether anaesthetic is delivered in hospital or dental surgery
Standards of resuscitation training set
Dental surgeries should be inspected and registered
Role of the general dental practitioner when suggesting anaesthesia?
Need to be aware of
- Risks of GA
- Alternatives to GA
- Process of care for GA
Patient selection
Patient preparation
Consent
ASA classification of a patient?
I Normal healthy patient
II Patient with mild systemic disease
III Patient with severe systemic disease that limits activity
IV Patient with severe incapacitating systemic disease (constant threat to life)
V Moribund patient with poor survival prognosis (< 24 hours)
Risk of death due to GA, in accordance to ASA classifcation of patient?
ASA 1 - 0.4 per 100,000
ASA 2 - 5 per 100,000
ASA 3 - 27 per 100,000
ASA 4 - 55 per 100,000