Anaesthesia Flashcards
Define General Anaesthesia?
“The reversible immobile state that induces amnesia”
Define nociceptive
Nociceptive pain is a type of pain caused by damage to body tissue.
Local Anaesthetics – Mode of Action
Blocking the generation and conduction of nerve impulses, resulting in
patients feeling no pain
Are sensory or motor neurons more sensitive
Sensory Neurons
5 stages of nervous Function is Lost?
- Pain
- Heat and cold sensation
- Touch
- Deep pressure
- Motor function
Why can local anaesthetics cross blood brain barrier
Lipid soluble and low molecular weight
Therapeutic effects of local anaesthesia
Anticonvulsants, sedatives and analgesia
Negative effects of local anaesthesia in high doses
Seizures
CNS depression
Slows myocardium conduction
effects of myocardial conduction
Depressing contractility
weak pulses
hypotension
bradycardia
cardiac arrest
Species more sensitive to local anaesthetic
Cats
(and exotics)
List local anaesthetic drugs
Lidocaine
Proxymetacaine
Bupivacaine
Lidocaine benefits
Rapid onset of activity
Good tissue penetration
Short duration of activity
Good for regional blocks and
general surgery
Lidocaine activity duration
- 45 minutes without adrenaline
- 1-2 hours with adrenaline
Proxymetacaine benefits
Topical analgesia of eye
Rapid onset
(Duration:15 minutes)
Bupivacaine effects
Good epidural analgesia
post-op anaesthesia
Potency x4 lidocaine
Bupivacaine onset of activity and duration
Slow onset of activity (15 minutes)
Longer duration of action (6-8 hours)
list the Local anaesthesia blocks
Local
regional
Epidural
Intra-articular
Peri-neural (regional) block locations
Intercostal nerve block
Brachial plexus block
Maxillary/mandibular nerve blocks
Intravenous regional block AKA
Bier block
What is a Perineural (Regional) Block
Local anaesthetic injected directly around nerve
What can be used to assist with Perineural (Regional) Block
Ultrasound or Nerve stimulator
Location of Intercostal nerve block site
caudal to ribs
Location of Brachial Plexus block site
Distal to elbow
Needle used for Epidural
Tuohy needle
or 22G spinal needle
Lumbosacral epidural provides analgesia to structures…
…caudal to
thoracolumbar junction
Epidural injected between which spinal vertebrae
space between L7-S1
Patients who are at particular risk during Epidural anaesthesia
Patients Shock (Hypovolaemic)
When Would an Epidural Injection be
Contraindicated?
Patient suffering septicaemia
skin over lumbosacral junction is infected
Patient with coagulation disorder
When are Intravenous regional anaesthesia, or Bier block used
surgical procedures in body’s extremities e.g. removal of a toe
What is an Esmarch bandage
Drain blood from a limb
Dissociative Anaesthesia effects
analgesia and amnesia
minimal effect on respiratory function
can be used with brief surgery
Swallowing and eyes remain open
Dissociative anaesthesia hyperexcitation signs
- Hypersalivation
- Hyperventilation
- Tachycardia
- Muscle twitches
- Paddling of the legs
- Curling of the tongue