anaesthetics Flashcards
What are the two types of general anaesthetic agents and what are each used for
Volatile agents: used to maintain but can be used in induction of needle phobic, children and those with difficult intubation (spontaneous resp continues for a bit)
Iv: used to induce, can be used throughout the surgery aswell if history of malignant hyperthermia, or more control over the depth of anaesthetic needed
What are the main cardiovascular effects and respiratory effects of GA
CV: hypotension, lowers BP and decreases CO, arrhythmias
Resp: respiratory depression, reduced response to hypoxia/hypercapnia, laryngospasm
What the main risks of GA
- MI, HF, HTN, Arrhythmias
- Resp infections, aspiration
- PONV
- Anaphylaxis
- Awareness
What are the three principles of GA
Narcosis= knocked out
Analgesia= pain free
Muscle Relaxant= floppy
Name some routes for local anaesthetic
EMLA subcut iv: biers block + toniquet epidural spinal
What are some advantages of regional aneasthesia
avoids systemic effects less risk of chest infections less cardiovascular complications reduces PONV (unless plus an opioid) less risk of DVT useful in post op pain management
Name some side effects of local when its accidentally intravascular or at too high a dose
mild: lip numbess, tongue tingling, slurred speech, light headed, visual disturbance, twitching
severe: generalised seizure, coma, resp depression, apnoea, cardiac arrest
How does an epidural work
Local anaesthetic eg. bupivicaine injected via catheter into epidural space (before dura), acts locally, level depends on amount, positioning and level of insertion
How does a spinal work
Single injection of local anaesthetic into subarachnoid space (csf), heavy so sinks down the spinal cord, and creates a complete sensory block.
level depends on positioning
What is a epidural headache
accidental puncture of the dura and leakage of csf causes severe frontal/occipital headache that changes on posture and worsens on straining
tx: blood patch to form clot and block the leak
What are the SE of epidural/spinal
Hypotension- preload with iv fluids
bradycardia
Name some contraindications to a spinal
surgery longer than 2 hours
surgery at level of or above the thorax
raised ICP
local/systemic infection
Describe the ASA classification of surgery from 1-6
1) healthy
2) mildly sick
3) Sick but not incapacitated
4) very sick and threat to life
5) will die in the next 24 hours without surgery
6) dead but going to harvest organs for donation
When is rapid sequence induction indicated
non-starved trauma patient to reduce risk of aspiration, dont know what the airway will be like so need difficult airway equipment near
What pre-op assessments are needed for everyone over 60yo
FBC and ECG
