2 - Anesthesia

Question 1

Normal pH of local anesthetics:

Answer 1

5.5 - 6.0

Do not work well in infected tissue (more acidic environment)

Can add bicarb to buffer

Question 2

How do most local anesthetics work?

Answer 2

Block Na channels and impair propagation of action potentials

Thinner nerve fibers and myelinated fibers are more easily blocked

Question 3

Advantages of epi in locals

Answer 3

Vasoconstrictor
Increased duration of action
Decreased bleeding
Decreased volume needed for anesthesia

Question 4

Disadvantages of epi in locals

Answer 4

Increased myocardial activity

Tachycardia
HTN
Dysrhythmias

Avoid in pts with known cardiac dz, HTN, DM, thyroid problems

Question 5

Describe the ideal anesthetic

Answer 5

Short latency
Superior penetration
Non-addictive
Completely reversible
Low toxicity
Stable and water soluble
Non-irritating
Inexpensive

Question 6

MC adverse effects of local anesthetic

Answer 6

Urticaria
Erythema
Edema
Dermatitis

Txt - O2, Epinephrine, fluids, antihistamine, steroids

Question 7

Toxicity from locals - prodromal sxs

Answer 7

Cicrumoral numbness / mouth tingling
Tinnitus
Lightheaded / dizzy
Metallic taste in mouth

Question 8

Toxicity from locals - CV problems

Answer 8

HTN then HOTN
Tachy or brady
CV collapse

Question 9

Toxicity from locals - severe CNS:

Answer 9

Tonic-clonic activity

ALOC -> unconsciousness

Question 10

What do you do prior to injecting to avoid intravascular injection?

Answer 10

Aspirate first

Question 11

Bupivicaine not recommended for:

Answer 11

Kids under 12yrs

Question 12

Lidocaine dosing

Answer 12

Maximum dose 4mg/Kg WITHOUT epinephrine up to 300mg

Maximum dose 7mg/Kg WITH epinephrine up to 300mg

1% lidocaine has 10mg/ml •

2% lidocaine has 20mg/ml •

Onset 2-5 minutes •

Duration 0.5-2 hours

Question 13

Management of toxicity

Answer 13

CNS sxs? Hyperventilate

CV sxs? IV fluids for HOTN, txt the arrhythmia

Malignant hyperthermia - MC to succ - txt with rapid cooling, bicarb, dantroline

Question 14

Method for injecting local

Answer 14

Large coverage with one puncture (longer, small gauge needle

Bent 45 degrees, hub the needle, inject as you withdraw

Question 15

Sequence of clinical anesthesia

Answer 15

Vasodilation - loss of sympathetic tone

Loss of pain/temp sensation

Loss of pressure sensation

Loss of motor function

Question 16

Peripheral nerve blocks - common sites?

Answer 16

Plantar aspect of foot
Palmar aspect of hand

Aseptic technique

Question 17

Max dose Bupivicaine?

Answer 17

2mg/kg up to 100mg

Question 18

Describe spinal (subarachnoid) block

Answer 18

Lower abdominal
Lower extremity
GU
GYN

Small volume of concentrated solution (anesthetic, narcotic, with or without epi)

Blocks sympathetic, sensory, motor function

Question 19

How to prevent toxicity?

Answer 19

Combine small amounts of different agents

Better than maxing out one thing

Question 20

Where is epidural anesthesia injected?

Answer 20

Into the epidural space, NOT the CSF

Question 21

Describe epidurals

Answer 21

Catheter taped to the skin

Requires continuous infusion of larger amounts of anesthetic

Blocks sensory but not necessarily motor function

Good for rib fx’s

Question 22

Acute complications of nerve blocks

Answer 22

HOTN (neurogenic shock)
- txt with fluids and pressors

High spinal - bradycardia, HOTN, arm tingling, respiratory distress (must ventilate)(diaphragm innervated by C3-C5)

Cauda equina - bladder and bowel dysfunction, motor and sensory changes in legs

Question 23

Later complications of central nerve blocks

Answer 23

MC - urinary retention
Monitor post-op UOP
May need catheterization (a foley is fine, they don’t need a suprapubic catheter)

Spinal HA 2/2 CSF leaking out of the dura - ICP decreases with postural changes - txt with IV fluids, caffeine, blood patch (autotransfuse blood into epidural space)

Epidural hematoma - compresses spinal cord - suspect if pt is anticoagulated - anesthesia will likely be avoided in these patients

Question 24

Dermatomes - Clavicles, nipples, umbilicus

Answer 24

Clavicles - C5
Nipples - T4
Umbilicus - T10

Question 25

Conscious sedation provides

Answer 25

Analgesia and anxiolysis Minimally depressed level of consciousness

Question 26

Usual combo for conscious sedation?

Answer 26

Benzo and narcotic OR Propofol and narcotic

Question 27

Intubation in conscious sedation?

Answer 27

Nope - patient maintains their own airway

Question 28

Nice perks of conscious sedation?

Answer 28

Still follows commands Doesn’t remember any of it later

Question 29

Examples of procedures in which conscious sedation is used

Answer 29

``` Bronchoscopy EGD/colonoscopy Thoracostomy Closed reduction of fx’s Procedures in kids ```

Question 30

What does propofol provide (and not provide)?

Answer 30

It’s a sedative-hypnotic So... anxiolysis, muscle relaxant, anticonvulsant BUT NO DIRECT ANALGESIC EFFECT

Question 31

Patient safety during conscious sedation

Answer 31

Have a crash cart there Follow your SOP’s NPO beforehand ASA class I and II patients Pt has a dedicated staff member (nurse) to monitor vitals, etc

Question 32

Crash cart:

Answer 32

``` O2 Airway adjuncts ACLS drugs Defibrillator Suction Narcan Flumazenil ```

Question 33

PACU

Answer 33

Home once goals are met: - stable out of bed for 30mins - stable vitals - fully responsive - ambulatory - oriented - pain / nausea controlled - voiding

Question 34

Goals of general anesthesia

Answer 34

Pain control Amnesia Muscle relaxation

Question 35

General anesthesia - airway mangement

Answer 35

Intubate or supraglottic Laryngoscope or Glidescope

Question 36

Fluids and blood products during general anesthesia

Answer 36

``` Central vs peripheral lines Continuous vitals IV fluids and UOP Protect eyes and pressure points Prevent hypothermia ```

Question 37

Complications of general anesthesia

Answer 37

Hypoxemia Aspiration (NPO pre-surgery, may use antacids, Sellick during intubation) Nerve injury (pad the pressure points, do not hyperextend joints, lubricate and tape eyes closed

Question 38

How do you feel about a local anesthetic?

Answer 38

Actually, I’d prefer an imported one.