Intro to Anaesthesia Flashcards
What is Anaesthesia?
A loss of sensation resulting from pharmalogical depression of nerve function.
What is General Anaesthesia?
A state of unconciousness produced by controlled reversible drug-induced intoxication of the CNS in which the patient neither PERCEIVES or RECALLS noxious stimuli.
What is Local Anaesthesia?
A temporary blockade of sensory nerves (usually simultaneously blocking motor nerves)
What is included in the “Triad” of GA?
Unconciousness ‘narcosis’, Muscle Relaxation, Analagesia ‘anti-noception’
What is the principle behind Balanced anaesthesia?
Using smaller doses of a combination of drugs to reduce the disadvantages. You use different drugs to block differnt parts of triad of GA.
What are the four stages in Anaesthesia?
Premedication, Induction of Anaesthesia, Maintenance of Anaesthesia, and Recovery.
What are the 3 main side effects of anaesthesia? (during)
Physiological depression of CVS and resp systems, Decreases homeostatic mechanisms (e.g. baroreceptors, pulomonary hypoxic response), and Specific drug effects.
What are the steps in pre-operative preparation of the patient?
History/signalment, Pre-anaesthetic exams/tests, Perioperative plan, Misc (clipping etc.), Premedication
What kind of clinical signs in a history would you look into before GA? Why?
Coughing (resp/cardiac disease), excercise intolerance (cardiac disease), PU/PD (kidney problems), Vom/diarrhoea (fluid/electrolyte), Trauma (blood loss), Seizures (CNS)
What questions would you want to ask or answers would you want to gain from history/signalment before GA?
Concurrent drugs, timing of last meal (fasting), previous anaesthetic responses, clinical signs that may need investigating.
What kind of exams/tests would you want to do before GA? What would you especially be looking for?
Physical exam, blood tests. Especially keeping an eye out for anaemias, low plasma proteins (hypoalbuminaemia), any evidence of kidney failure, cardiac disease.
How would Anaemia affect the conduction of Anaesthesia?
Oxygen content is reduced, and therefore cardiac output will need to be increased to maintain O2 delivery. Most Anaesth drugs decrease CO, and so blood transfusion may be necessary.
How would Hypoalbuminaemia affect the conduction of Anaesthesia?
Many anaesthetic agents are highly protein bound and hypoalbuminaemia will increase the amount of free (unbound) drug, so that a greater response is seen with a given dose.
How would Azotemia affect the conduction of Anaesthesia?
Usually indicates renal disease or dehydration. Concurrent acidosis increases free drug concentrations, changes resting membrane potential (resulting in myocardial depression), O2 dissociation curve shifted to the right (reducing oxygen affinity).
What types of drugs would you expect to be included in Premedication?
Sedation, analegesics (potentially anti-cholinergics)
