Anaesthetic Flashcards
Define anaesthesia
“loss of sensation”
How do drugs causing anaesthesia work?
they block signals that pass along nerves to the brain
what occurs when these anaesthetic drugs wear off?
- normal sensation regained (including pain)
define conscious sedation
a drug depressing the CNS where VERBAL CONTACT with the patient is maintained throughout the period of sedation
what make general anaesthetic particularly difficult in dentistry and MFS?
where we want to work is where the anaesthetist wants to place tubes that will maintain an open airway
what route of drug delivery induces anaesthesia?
intravenous
what are 3 IV drugs that can induce anaesthesia?
- propofol
- thiopental
- etomidate
what form of drug delivery will maintain anaesthesia?
inhalation
what 2 drugs are inhaled to maintain anaesthesia?
- oxygen and nitrous oxide
what are often given as premedication to reduce the amount of other agents are required for anaesthesia?
benzodiazepines
how many stages of anaesthesia are there?
4
what is stage 1 of anaesthesia?
loss of consciousness
what is stage 2 of anaesthesia? what may occur at this stage?
excitement or delirium
coughing, vomiting and struggling
what occurs at stage 3 of anaesthesia?
- laryngeal reflex lost
- pupils dilate
what stage of anaesthesia must you have before surgery?
stage 3
what can occur to the respiratory systems during stage 3 anaesthesia?
from onset of autonomic respiration to respiratory paralysis
what can occur at stage 4 anaesthesia?
cessation of respiratory system to death
what are the 2 subdivisions to muscle relaxants?
short acting
long acting
name a short acting muscle relaxant.
suxamethorium
why would a muscle relaxant be useful?
- surgical access to body cavities (esp abdomen)
- allowing incubation (an aid for ventilation)
name a long acting muscle relaxant and how long does it last?
atracurium (30 mins)
before a GA what are the most significant aspects of the medical history?
- cardiac
- respiratory
- diabetes
- epilepsy
- bleeding disorders
- acid reflux
- past surgery
- allergies
what is malignant hyperthermia?
- an inherited disorder of skeletal muscles ONLY TRIGGERED BY CERTAIN ANAESTHETIC DRUGS.
- an abnormal accumulation of calcium in muscle which leads to hyper metabolism
what are the two consequences of muscle hypermetabolism?
- muscle rigidity
- muscle breakdown
what is the mortality rate of malignant hyperthermia?
just under 2% - an anaesthetic emergency
what are 4 ways to indicated malignant hyperthermia
- temperature increase
- unexplained CO2 levels during expiration
- unexplained tachycardia
- unexplained increased need for oxygen
what is the only drug that will be effective in limiting MH process?
Dantrolene
