Guided learning- Anaesthetics Flashcards
(40 cards)
3 a’s of conciousness?
- alertness -> upper brainstem reticular formation
- awareness -> cerebral cortex
- attention -> limbic system frontoparietal association areas
definitions:
normal
fully orientated time place and person
define sedation
allows patients to tolerate unpleasant diagnostic or surgical procedures
relieves anxiety and discomfort
verbal contact can be maintained
define coma
state of extreme unresponsiveness
individual exhibits no voluntary movement or behaviour
define anaesthesia
no concious awareness
patient without feeling or sensation
enters a drug induced and predictably reversible coma
define : concious sedation
patient relaxed and calm
able to undergo minor surgical procedures w/out too much discomfort
can maintain verbal contact
3 levels of sedation and effects
- minimal sedation
- airway unaffected
- CV function unaffected
- normal responsiveness
- spontaenous ventilation unaffected
- reduced anxiety
- moderate sedation / concious sedation
- no airway intervention
- CV usually maintained
- responsive to verbal and tactile stimulation
- sponatenous ventilation is adequate
- Deep sedation (anaesthesia in UK)
- Airway intervention may be required
- CV function usually maintained
- responsive to purposeful repeated or pain stimulation
- spontaenous ventilation may be inadequate
3 scales of sedation?
- Ramsay (6 point)
- richmond sedation agitation scale (10 point)
- Riker sedation agitation scale (7 point)
Ramsay scale
aim?
levels
- aim for level 2 -> cooperative, oriented, calm
- 1 = agitated
- 2 = aim 3 = Response to verbal
- 4 and 5 = brisk / sluggish response to glabellar tap or loud auditory stimulus -> elicit blink reflex
- 6= unresponsive
- note unvalidated atm

Richmond scale
aim?
levels
- 10 point scale with -5 being unarousable and +4 being combatitive/ violent to staff.
- Aim for between 0 and -2:
- -2 = light sedation, briefly awaken with eye contact to voice under 10 s
- -1 = drowsy, not fully alert but sustained eye contact to voice more than 10 s
- 0 = alert and calm

Riker sedation agitation scale
aim?
levels
- 7 point scale
- Aim : level 4 -> calm, coopertive, easily arousable, follows commands
- 7 = dangerous agitation
- 1 = unarousable

What is the aim in anaesthesia?
- always aim for calm and relaxed
- allows procedure to be performed
- reduces agitation
- if too sedated prolongs recovery and longer procedure time
Normal pupil sizes in light and dark ?
Pupillary responses during anaesthesia?
What is always checked for in the anaesthetised patient?
- Light -> 2 -4 mm
- dark -> 4-8 mm
- Overdose -> FULL DILATION
- Deep surgical anaesthesia (stages 2 - 4 ) -> 6-8 mm DILATED
- brainstem function reduced
- diaphragmatic respiration
- eye and resp reflexes reduced
- Light surgical anaesthesia (stage 3) -> MIOSIS, CONSTRICTED
- PNS takes over
- reflexes dampened
- Analgesia (stage 1) -> 2-4 mm NORMAL
- conciusness not sig. affected
- Always check for pupillary light reflex and corneal blink reflex

What drugs are used for sedation
- SEDATION = BOrED
- Benzodiazepines
- Opiates
- Entonox
- Dexmedetomidine
Name the benzodiazepines used in sedation
What is the MOA
- Midazolam
- Lorazepam
- Diazepam
- Temazepam
MOA: Binds Y subunit of GABAa receptor, PAM
increase affinity for GABA and freq of channel opening
increase Cl- conductance into cell
HYPERPOLARISES cell reduce AP firing
Benzodiazepines:
USES
SE’s?
- Sedatives, muscle relaxants (hyperkinetic disorder)
- anxiolytic and panic disorder
- epilepsy
- chronic insomnia
SE’s:
- memory loss
- no analgesia
- decrease cog. function on recovery from sedation
- prolonged use can result in tolerance and dependency
- avoid in patients with heart/ resp/ liver problems or depressive / -ve sx.
Benzodiazepines:
reversal agent?
Flumazenil
(Shoo Benzo or ill give ya the FLU)
OPIATES:
name 3 short acting used in sedation
MOA?
- FENTANYL -> Short acting and strong
- AFENTANIL
- REMIFENTANIL
MOA:
Binds mu opiod R , GPCR (Gi/ Go)
Promotes opening Katp and Kir channels, inhibits opening VGCC and inhibit NT release via exocytosis block.
HYPERPOLARISATION via K+ efflux, and decreased NT release
Decrease neuronal transmission
OPIODS:
1) cardinal signs of OD
2) reversal agent?
3) Adv’s?
4) adjunct to what?
- Pinpoint pupils (miosis)
- Respiratory depression
- Coma
Reversal -> Naloxone (shorter acting antagonist) (Naltrexone longer acting)
Adv: good sedatives, analgesics, SM relaxants ,
adjunct to anaesthesia:
- counteracts increase in CV and RR during invasive treatment
- decrease dose of anaesthetic required as sedative effect
- fast acting used as adjunct to prevent resp depression and OD
SEDATIVES:
Name inhaled sedative
MOA
onset
adv’s
disadv’s
ENTONOX = Nitrous oxide 50: 50 mix O2 and N2O
Onset 2- 3 mins
MOA: unclear modulates range of R may induce opiod release
Adv’s: sweet smelling, non airway irritant, good analgesic
Disadv : potential teratogen, increase ear and lung pressures
SEDATIVES:
Name sedative used in ICU
Moa?
Dexmedetomidine
Used in ICU for procedures when patient needs to maintain verbal contact
MOA: selective alpha2 adrenoR AGONIST
Binds presynaptic adrenoR to inhibit NA release and terminate pain signals
postsynaptically inhibits SNS -> reduce BP and HR
3 main effects of anaesthetics?
Two main groups?
Unconciousness (Reticular formation and reticular activating system)
Loss of reflexes
Analgesia
Two main groups : 1) Local 2) General
Name 3 local anaesthetics
Two groups and metabolism T 1/2
MOA?
- LIDOCAINE (amide)
- BUPVICAINE (amide)
- LEVOBUPVICAINE (amide)
Two groups :
1) Amino Amides metabolism in LIVER, longer T 1/2 (3 Hrs)
2) Amino Esters metabolism in PLASMA, T 1/2 3 mins
MOA -> inhibit VG Na channel, dampends neuronal activity by inhibiting depolarisation, reduced sensory transmission to the cortex
Enter channel when open and by crossing PM and binding from the inside.
uses and duration of:
Lidocaine
Bupvicaine
Levobupvicaine
Lidocaine: Nerve block, dental and topical procedures
duration 1-2 hours
Bupvicaine: regional IV anaesthesia, peripheral nerve block, epidural and SNS nerve block
Duration 1- 3 hours
Levobupvicaine: same as Bupvicaine (regional IV anaesthesia, peripheral nerve block, epidural and SNS nerve block)
Duration 1-3 hours
+ Less cardiotoxic than bupvicaine (would not used bupvicaine in HF patient)