Week 5 Upper Peripheral Nerve Blocks Flashcards
What are the five indications for regional anesthesia?
Primary anesthetic post-operative pain management history of severe PONV or risk of MH Patient is too ill for general anesthesia physician (surgeon) preference
Benefits of Regional Anesthesia (6)
decreased risk of PONV decreased postop pain decreased LOS increased patient satisfaction maintained upper airway adn pharyngeal reflexes increased gastric mobility
Absolute contraindications for regional anesthesia (4)
patient refusal
active bleeding in anticoagulated patient
proven allergy to a local anesthetic
local infection at the site of the proposed block
Relative contraindications for regional anesthesia
respiratory compromise
uncooperative patient/ neurological disease/psychiatric disease
an anesthetized patient
bleeding diathesis secondary to an anticoagulant or genetic disorder
blood stream infection
pre-existing peripheral neuropathy
Complications of Regional Anesthesia (4)
intravascular injection/LAST
direct nerve injury/intraneural injections
vascular injury/hematoma
infection
What region has the highest incidence of LAST?
epidural> axillary > interscalene
What is LAST?
local anesthetic systemic toxicity
systemic delivery of large quantities of LA via inadvertent intravascular injection
What channels are depressed with LAST?
Sodium, potassium and calcium
Neuro and cardiac symptoms of LAST
lack of inhibition of excitatory neurons-> seizure
cardiac: decreased contractility, arrhythmias (brady first), vfib most serious
What LA carries the most reported deaths?
Bupivacaine
What drugs are less cardiotoxic for LAST?
shorter acting drugs
What are clinical signs of LAST?
progressive CNS excitation agitation tinnitus circumoral numbness blurred vision metallic taste muscle twitching unconsicousness seizure cardiac and respiratory arrest
What are safety precautions for LAST?
ultrasound guided regional anesthesia aspiration before injection incremental injection lower doses test dose awake/sedated patients midazolam
Treatment of LAST
prompt recognition and diagnosis
airway management priority (seizure suppression, benzo) prevent hypoxia and acidosis
Lipid emulsion therapy
Vasopressors Epi< 1mcg/kg, no vasopressin
What is the dose for lipid emulsion therapy?
1.5ml/kg 20% rapidly Q2-3minutes
infusion 0.25ml/kg/min (IDW)
What are the benefits of UGRA vs. traditional landmark technique?
Visualization improvement of block quality use of lower doses of local anesthetic less painful administration improved patient satisfaction safer
What can you visualize with the US?
anatomic structures
real time needle movements
spread of LA
Define UGRA
in-plane/longitudinal preferred allows visualization of entire needle
What is an ART manuever?
alignment- sliding
rotation
tilting- maximizing angle of incidence of beam to target structure
Where are the peripheral nerve stimulators placed?
negative lead attaches to skin
positive lead attaches to needle
Define peripheral nerve stimulator for regional anesthesia?
controlled stimulating pulse of variable amplitude
What is the goal of peripheral nerve stimulator?
maintenance of motor stimulation with minimal amplitude
When using the PNS, when do you stop?
if motor response seen with <0.2mA
chance of intraneural injection
When do you turn on the stimulator?
when the needle has entered the skin