Principles and Pharmacology Flashcards
Operative mortality vs Anaesthetic mortality
1 in 25
vs
1 in 400,000
Which system is used to classify patient fitness for undergoing anaesthetic?
American Society of Anaesthesiologists Classification
ASA
1- Normal, fit
2- Mild systemic disease
In which group of ASA classification is mortality concentrated?
Groups 3-5
Severe systemic disease to brain-dead
What is the triad of anaesthesia?
- Analgesia
- Hypnosis
- Relaxation
Types of medication used for Analgesia
Opiates
General anaesthetic
Local anaesthetic
Types of medication used for Hypnosis
General Anaesthetic
Types of medication used for Relaxation
Muscle relaxants
LA
GA
Complications of Anaesthesia
Polypharmacy
Muscle relaxation
Separation of hypnosis and relaxation
What effect does GA have on neuron channels?
Hyperpolarises - less likely to fire
Action of inhalational GA
Dissolves in membranes
Action of IV GA
Allosteric binding
GABA receptors open chloride channels
Which functions are lost first under GA?
Cerebral functions- more complex
Which functions are relatively spared under GA?
Reflexes - more primitive - small number synapses
Management priorities
ABC Airway management Respiratory function Cardiovascular impact Care for unconscious
Name two intravenous anaesthetic agents
Thiopentone
Propofol
Features of IV anaesthetics
Rapid onset of unconsciousness
Rapid recovery
Which tissues are slow to effect of IV anaesthetics?
Muscle- slow but large effect
Fat - fat solubility - storage
In which tissues/organs does IV anaesthetics exhibit a quick effect and quick decline?
Blood and vessel rich organs (brain)
Which compounds are Inhalational Anaesthetics>
Halogenated hydrocarbons
Mechanism of Inhalational Anaesthetics
Uptake and excretion via lungs
Which direction does the concentration gradient flow for inhalational compounds>
Lungs -> blood -> brain
How is the potency of inhalational anaesthetics measured?
Using Minimum Alveolar Concentration
Low = high potency
Inhalational anaesthetics cross the alveolar basement membrane easily. How does this impact arterial concentration of the drug?
Arterial concentration roughly equal to alveolar partial pressure
Sequence of general Anaesthesia
What is mostly used for induction?
Intravenous
