Anesthesia Flashcards
1
Q
Diff types of anesthesia?
A
- general: suppression of activity in CNS, unconsciousness and total lack of sensation
- sedation: inhibition of transmission of nerve impulses b/t higher and lower centers of the brain inhibition of anxiety and memory
- regional: use of local anesthetics to make a portion of body insensate by blocking transmission of nerve impulses b/t a part of body and spinal cord -
peripheral: inhibits sensory perception w/in a specific location, nerve blocks.
central: local anesthetic delivered around spinal cord and removes sensation of body below level of bloc (spinal and epidural)
2
Q
Endpts of anesthesia? Agents used?
A
- analgesia: opiates, local anesthetics, ketamine, NSAIDs
- amnesia: benzos
- hypnosis: barbiturates, propofol, etomidate
- immobility: muscle relaxants
- hemodynamic stability: BBs, sympathomimetics
3
Q
Risks of anesthesia?
A
- death
- MI
- PE
- post-op N/V
4
Q
What is the ASA classification?
A
- American society of anesthesiologists - classification of pt’s physicla status
- the greatest predictor of the probability of a complication occuring
- higher the ASA class = increased likelihood of surgical or anesthetic complications
5
Q
ASA classes?
A
- ASA I: a normal healthy pt (no smoking, no or very minimal drinking)
- ASA II: pt w/ mild systemic disease, (smoker, more than min. drinking, pregnancy, obesity, well controlled diabetes, well controlled HTN, mild lung disease)
- ASA III: pt w/ severe systemic disease, not incapacitating (diabetets, poorly controlled HTN, distant hx of MI, CVA, TIA, cardiac stent, COPD, ESRD, dialysis, hepatitis, pacemaker, EF below 40%)
- ASA IV: pt w/ severe systemic disease that is a constant threat to life ( recent hx of MI, CVA, TIA, cardiac stent, ongoing cardiac ischemia or severe valve dysfxn, implanted ICD, EF below 25%)
- ASA V: moribund pt who isn’t expected to survive w/o the operation (ruptured abominal or thoracic aneurysm, intracranial bleed w/ mass effect, ischemic bowel in face of sig cardiac pathology)
- ASA VI: a pt who has already been declared brain dead and whose organs are being removed for transplant
6
Q
What is regional/local anesthesia?
A
- pain blocked from a part of the body using local anesthetics
7
Q
Types of regional anesthesia?
A
- infitrative
- peripheral nerve block
- IV regional anesthesia
- central nerve blockade
- topical anesthesia
- tumescent anesthesia
8
Q
What is infiltrative anesthesia?
A
- local anesthetic injected into small area to stop sensation
9
Q
What is a peripheral nerve block?
A
- local anesthetic injected near a nerve that provides sensation to portion of the body
10
Q
What is IV regional anesethesia (aka Bier block)?
A
- dilute local anesthetic infused to a limb through a vein w/ a tourniquet placed to prevent the drug from diffusing out of the limb
11
Q
What is a central nerve blockade?
A
- infusion or injection of local anesthetic in or around a portion of the CNS
- spinal (intrathecal) and epidural
12
Q
What is topical anesthesia?
A
- special formulation that diffuses through the skin or mucous membranes (EMLA patcthes)
13
Q
What is Tumescent anesthesia?
A
- large amts of dilute local anesthesia infiltrated into subq tissue used in liposuction (puff up surrounding tissue w/ anesthesia)
14
Q
Indications and CIs for Neuroaxial anesthesia?
A
Indications:
surgery or pain
appropriate distribution
CIs:
pt refusal
infection
coagulopathy
15
Q
Benefits of spinal anesthesia?
A
- decreased surgical time by 12%
- 25% less blood loss
- 50% less intraop transfusion requirements
- may decrease the incidence of DVT or PE
16
Q
Benefits of epidural anesthesia and analgesia? Complications?
A
- less blood loss
- reduced platelet aggregation
- reduced stress response to surgery
- decreased incidence of DVT
- improved graft patency after LE revascularization
- pts w/ combined (general and epidural) for aortic surgery had lower incidence of death and major periop complications
- complications:
MC: post procedural HA
spinal hematoma or abscess
17
Q
Comparison of spinal and epidural anesthesia?
A
Spinal: - location of injection: lumbar region only (below L2) - no specific levels affected - many times just a 1 time dose
Epidural:
- injection: anywhere along the spine
- specific levels: chest, abdomen, pelvis and legs
- often a catheter is left in place for multiple injections
18
Q
Diff nerve blocks? How do you localize?
A
- brachial plexus: interscalene, supraclavicular, axillary
- digital block (no Epi!!)
- use paresthesias, US, and nerve stimulation for nerve localization
19
Q
How does a nerve block work?
A
- blocks Na channels
20
Q
Diff types of local anesthetics?
A
- Esters:
short infiltration: 45-60:
procaine (novocaine), 2-chloroprocaine
long infitration 180-360 - tetracaine - Amides:
intermediate: lidocaine, mepivacaine
long: bupivacaine, Ropivacaine
21
Q
Differential block - concentration and block produced?
A
- low concentration = sympathetic block
- intermediate = sensory
- high = motor
- anesthetic effect: dose dependent
22
Q
Diff blocks dependent on diff agents?
A
- Bupivacaine:
sympathetic: 0.125% and below
motor: 0.5% and greater - lidocaine:
sympathetic: below 0.5%
motor: 2% and greater
23
Q
Why do we add Epi to LAs?
A
- prolong surgical anesthesia time: procaine from 45-60 to 60-90min lidocaine from 75-90 to 90-180 min bupivacaine from 180-360 to 200-400 - decrease peak serum levels - intravascular marker - decrease surgical site bleeding
24
Q
When should you not add epi?
A
- when vasoconstrictive properties of Epi may compromise tissue perfusion (end arteries)
- fingers/toes
- penis
- ear/nose
- skin flaps
25
Local anesthetic toxicty of lidocaine?
low plasma levels to high levels of lidocaine:
- dizziness
- tinnitus
- shivering, dysphoria, nystagmus
- somnolence, muscle twitching
- seizures
- cardiac arrhythmias
- **CV instability and collapse
26
Tx for local anesthetic toxicity?
1. stop injection
2. call for help
3. supportive care (ABCs)
4. 20% intralipid 1.5ml/kg/min, may repeat bolus (1-2x)
5. cardiopulmonary bypass
