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!!!!! Advanced Anesthesia I !!!!! > Orthopedic Surgery > Flashcards

Orthopedic Surgery Flashcards

1
Q

Orho surgery to hand and wrist will NOT use this block. Why?

A

Interscaline

Incomplete block of ulnar nerve 15-30% of the time

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2
Q

Beir block

  1. Advantage
  2. Disadvantage
  3. Time
  4. Tournequate specifics
  5. Local
  6. Complications
A
  1. pemits more extensive surgery and longer surgical time
  2. Does Not provide post op pain
    • (will then use infraclavicular block for post op pain controll)
  3. Short procedures >30 min, but <1 hour
  4. Double tourniquet
    • inflate upper (proximal) first → after 15 min inflate distal → then let down upper
    • Inflate to 250mmHg and record times
  5. 50mL 0.5% lidocaine = 250mg
  6. Comlications = tourniquet failure, LA toxicity
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3
Q

Surgery to the arm

Brachial plexus blocks used

A
  1. Infraclavicular
  2. Interscaline
  3. Axillary
  4. Contiuous (kept in for 4-7 days)
    • 0.125% bupivicaine
    • prevents vasospasm and improves circulation
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4
Q

Supraclavicular block

A

“Spinal of the arm”

  1. Trunks (middle/inferior)
  2. Upper arm to hand
  3. May cause ipsilateral phrenic nerve paralysis (50%)
    • CANNOT use if patient has contralateral paralysis of phrenic nerve
    • Horners Syndrome “Horny PAM’
      • ptosis, anhydrosis, meiosis
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5
Q

Infraclavicular

A
  1. Lateral, posterior and medial cords
  2. Used in Elbow, forearm and hand surgery
    • Preferred over axillary block for elbow surgery
  3. spares musculocutaneous nerve
  4. Must traverse pectoralis major and minor = pain
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6
Q

Interscaline Block

A
  1. Roots/trunks
  2. Used for surgery from shoulder to hand
    • ​​Ulnar sparing
  3. higher CNS toxiticy risk
    • Close proximity to vertebral artery, corotid artery and juggular vein
  4. Landmarks: at the level of C6 the interscaline grove
    • between aneterior and medial scaline muscle posterior to sternocleoidomastioid muscle
  5. Complications:
    1. ​Horners syndrome + phrenic nerve block (100%)
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7
Q

Axillary block

A
  1. Median, Ulnar and radial nerves
  2. Used for procedures below the elbow
  3. Transarterial approach = 1/2 local ingected on each side of artery
    1. Radial nerve = Posterior to axillary artery
    2. Ulnar nerve = Inferior to axillary artery
    3. Median nerve = Anterior (superioir) to axillary artery
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8
Q

Prefered block for elbow surgery

A
  1. Axillary
    • Supraclavicular + infraclavicular risk pneumothorax which ususally occurs 6-12 hours after discharge
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9
Q

Decompression of pneumothorax

A
  1. Ideally chest tube (releive increased intrathoracic pressure)
  2. 14-18 guage IV angiocath
    • Anteriorly to 2nd or 3rd intercostal space
    • laterally to 4th or 5th intercostal space
    • keep catheter in place until chest tube can be placed
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10
Q

Muscles and innervation of the rotator cuff

A
  1. suprapinatus and infraspinatus muscles
    • suprascapular nerve
  2. teres muscle
    • axillary nerve
  3. subscapularis
    • subscapular nerve
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11
Q

Where should BP be measured when patient is in the beach chair position?

A
  1. at the level of the auditory meatus of the ear
    1. (location of the base of the brain and the circle of willis)
  2. BP cuff on the arma by be 7-22mmHg LOWER than the brain!
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12
Q

Blood loss comparison for Shouler arthroscopy and arthroplasty

A
  1. arthroscopy = minimal (need 1 IV)
  2. arthroplasty = up to 1000mL (need 2 large bore IVs)
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13
Q

Advantages and risks of beach chair position:

A

Advantages

  1. Improves visualization & decreases distortion of intra-articular anatomy

Risks

  1. Neck stretch/Cervical spine injury (avoid head dislodgement)
    • Flexion of neck = obstruct internal jugularvein = venous engorgement
    • Extension may impair CBF = cerebral ischemia
  2. Venous air embolism/pneumothorax
  3. Cerebral hypoperfusion/stroke risk
    • must reference SBP @ level of brain
  4. Eye injury (avoid deliberate hypotensive technique)
  5. Hypotensive bradycardiac events (HBE)
    • assoc w interscalene block (30% of pt).
    • A decrease HR 30 beats/min within 5 min interval, decrease BP 30 mmHg or any systolic BP below 90.
    • Etiology unknown/ is transient.
    • Bezold-Jarish reflex-proposed mechanism
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14
Q

Bezold-Jarish reflex-proposed mechanism

A
  1. inhibitory reflex mediated through cardiac sensory receptors with a vagal efferent limb.
  2. When in beach chair the enhanced venous pooling leads to increase sympathetic response and activation of increased vagal tone.
  3. The combo venous pooling and vagal tone can be difficult to rapidly reverse.
  4. Epi in local may have a role-increases cardiac hypercontractility as well as exacerbates position related hypovolemic state
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15
Q

Risks of lateral decubitus positioning

A
  1. Musculocutaneous nerve injury (lateral aspect of the arm
  2. Fluid related obstructive airway comprimise
  3. V/Q mismatch -
    1. dependent lung (down) has more profusion and less ventilation (zone 3)
    2. non-dependent (upper) has more ventilation and less profusion (Zone 1)
  4. Decreased CO due to downward and left shift of mediastinum = decreased venous return leading to decreased CO
    1. treat with fluids and vasoactive meds
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16
Q

Regional vs General for lower extremety surgery

A

For total hip replacement

  • studies show decreased blood loss under neuroaxial block compared to general
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17
Q

LMWH and lower extremety surgery

A

High risk for DVT/PE (>50% incidence WITHOUT prophylaxis, and 10-20% incidence WITH prophylaxis)

  1. Hip
  2. knee
  3. hip fracture repair
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18
Q

Physiologic effects of hypothermia

A
  1. Shivering
    1. leads to metabolic acidosis
    2. increases oxygen consumtion up to 600%
    3. Left-shift in O2 Hg disassociation curve = decreased oxygen delivery to tissues
    4. Increases cardiac irritability
  2. Reduced platelet function = increased bleeding
  3. depressed neuronal ativity and increased seizure threshold
19
Q

Hypotensive technique

A

NOT recommended for upper extremity surgeries, recommended for lower (total hip and knee)

20
Q

Methyl Mythacrolyate (MMA) cement

USE

A
  1. Binds prosthetic with bone
  2. Cement mixing is an exothermic reaction
    • expands cement causing pressure against bone surfaces
  3. Intramedullary HTN pushes fat, air and marrow into the femoral venous channels
21
Q

Methyl Mythacrolyate (MMA) cement

Physiologic changes

A

Bone cement implant syndrome

  1. Decreased SVR
  2. HYPOtension
  3. Hypoxia
  4. Cardiac arrythmias
    • increased PVR, loss conciousness, cardiac arrest
22
Q

First signs of BCIS (Bone cement implant syndrome)

A
  1. First sign under GA is drop in ETCO2
  2. First sign under regional is dyspnea and altered sensorium
23
Q

Treatment of BCIS (Bone cement implant syndrome)

A
  1. 100% FiO2
  2. Aggressive fluids
  3. Correct hypotension with Alpha agonists

Prior to Cement

  1. BP should be optimized
  2. Turn on 100% FiO2
  3. have full bags of fluid on pressure bags ready
  4. Document cement time
24
Q

Causes of BCIS from MMA

A

Unknown etiology

  1. Possibly direct vasodilation or cardiac depression from MMA
  2. Possibly Pulmonary emboli caused by the forced entry of air, fat or bone marrow into the venous system (EtCO2 Drop)
25
Q

How long can hypoxia last from methylmathacylate?

A

It can las tp to 5 days

  • judicious use of opioids –> may further hypoxia via hypoventilation or airway obstruction
  • Continuous pulse ox monitoring
  • fluid management and diuresis
26
Q

Surgery MOST associated with bone cement implantaion syndrome (BCIS)

A

HIP Replacement

(less common in elective procedure and more common in high risk groups)

27
Q

Risks associated with Hip Arthroplasty procedure

A
  1. MMA causing BCIS
  2. Hemorrage
    • can lose > 1500cc blood
      • T&C, warm fluid, LArge bore IV 18g
    • Epidural or hypotensive technique may decrease blood loss
      1. spinal = more hypotension than epidural d/t rapid onset
28
Q

Considerations with surgery for fractured neck of femur

A
  1. Patient usually > 80 yrs and has dimentia
  2. ASA status influences mortality
    • Most common casues of intraop death = MI & PE
    • Post op PNA contributes to mortality
  3. Use of fracture table (allows for x-rays)​
    • Pad perineal (crotch) post
  4. Regional reduces postoperative risk of death, pulmonary complications, and DVT by 30-50%!
29
Q

Fat Embolism symptom triad

A
  1. Dyspnea
  2. Cunfusion
  3. Petechiae to chest
30
Q

How to identify Fat Embolism under GA

A
  1. Sudden drop in EtCO2
  2. decreased arterial oxygenation
  3. EKG changes

(usually within 72 hours postop of long bon fracture

31
Q

Knee arthroscopy and CHF

A

if irrigating fluids are used, there can be systemic absorbtion

32
Q

Nerve innervation of the foot

A
  1. deep and superficial paroneal
  2. sural
  3. Saphenous
  4. posterior tibial

Saphenous is the only one from the femoral nerve; all others are derrived from the sciatic nerve

33
Q

What two things do you want to avoid with Cervical spine surgery?

A
  1. Avoid the Sniffing Position
  2. Avoid cricoid pressure
34
Q

where does degerative disease most liely occur in the cervical spine?

A

C5-C7

35
Q

why use SSEP?

A
  1. To determine surgical impingement on spinal roots
  2. Monitor posterior (sensory) spinal cord function.
36
Q

Paath of the current for SSEP monitoring

A

current delivered to the peripheral nerve;

if the nerve is intact,

electrical potential will transmit to the contralateral sensory cortex

37
Q

Do NMB impact SSEP?

A

No they do not, because the measurement is the posterior sensory component of the spinal cord,

NMB do impact motors

38
Q

What is the best anesthetic choice for SSEP?

A
  1. TIVA = Best choice
  2. the 0.5MAC with 50% nitrous
    • this can still produce unreliable results
39
Q

How can hypotension be detected with SSEP monitoring

A

A decrease in SSEP signal despite no change in anesthetic

40
Q

Where do the dorsal colums of the spinal cord receive their blood supply from

A

The posterior spinal arteries

41
Q

Most common monitoring sites for SSEPs

A
  1. Upper extremeties = Median nerve
  2. Lower extremeties = Posterior tibial nerve
42
Q

two places recording electrodes are placed for SSEPs

A
  1. Scalp and cervical spine
43
Q

This drug decreases optic nerve profusion

A

phenylephrine

!!!!! Advanced Anesthesia I !!!!! (9 decks)

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