VAE & LAST Flashcards

1
Q

Mechanism of a VAE

A
  • CO2 bolus enters venous circulation
  • travels back to R atrium via IVC
  • causes a gas lock blocking flow from RV to pulm system
  • decreased VR & CO
  • hemodynamic collapse
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2
Q

Symptoms indicative of VAE

A
  • rapid decrease in EtCO2
  • HoTN
  • hypoxemia
  • increased CVP
  • EKG changes
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3
Q

Most sensitive monitoring modality for air

A

TEE

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4
Q

Decreased EtCO2 seen in VAE is d/t…

A
  • decreased pulmonary BF
  • increased alveolar dead space
  • dilutional expired CO2
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5
Q

Treatment of VAE should include…

A
  • communicate
  • release pneumoperitoneum
  • flood field with NS
  • d/c N2O
  • Durant’s maneuver
  • place surgical site below level of heart
  • 100% O2
  • CVP placement to aspirate air from RA
  • pressors if needed
  • rapid IVF
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6
Q

Key symptom that differentiates fat embolism from air embolism

A

fat embolism = petechiae

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7
Q

High risk patients for VAE

A
  • sitting positions
  • op site above level of heart
  • line placement
  • operative hysteroscopy
  • CO2 insufflation
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8
Q

Areas with greatest potential for intravascular absorption of LA

A

I Think I Can Please Everyone But Susie & Sally
IV - Tracheal - Intercostal - Caudal - Paracervical - Epidural - Brachial Plexus - Subarachnoid - Sciatic - SQ

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9
Q

Symptom presentation of LAST

A
  • CNS excitement
  • Seizure or CNS depression
  • CV toxicity
    wide presentation
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10
Q

Mild to moderate LAST symptoms

A
  • circumoral numbness
  • disorientation
  • metallic taste
  • tinnitus
  • vision changes
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11
Q

Severe LAST symptoms

A
  • coma
  • resp arrest
  • seizure
  • unconsciousness
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12
Q

At exceedingly high LA plasma concentrations…

A
  • cardiac arrest
  • HTN –> HoTN
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13
Q

Conditions that potentiate LAST

Why?

A
  • hypoxia
  • hypercarbia
  • acidosis

–> vasodilate cerebral vessels, enhancing delivery
–> H+ ions bind to protein and decrease protein binding of LA

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14
Q

Lipids should be initiated in LAST…

A

at first sign of potential LAST

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15
Q

Preferred medication class to treat LAST-associated seizures:

A

Benzos
or
Propofol

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16
Q

Lipid dosing

A

> 70kg:
100mL bolus over 2-3min
200-250mL infusion over 15-20min

<70kg:
1.5mL/kg bolus over 2-3 min
0.25mL/kg/min infusion

17
Q

Maximum lipid dose

A

12 mL/kg

18
Q

Patient experiencing LAST had their first lipid bolus and 15min infusion but remains unstable. Next steps…

A

repeat initial bolus (100mL)
double infusion rate

19
Q

Effects of intralipids

A
  • lipid sink (sequesters LA)
  • enhanced FA metab
  • inotrope (increased Ca2+ influx)
  • membrane effect (impairs LA binding to voltage-gated Na channels)
20
Q

Complications of LAST

A
  • CV collapse
  • hypoxic brain injury
  • status epilepticus
  • recurrence of systemic toxicity
  • death
21
Q

LAs affect 3 cardiac functions:

A

1) cardiac action potential
2) myocardial function
3) SVR

22
Q

LA with greatest affinity for Na+ channels:

A

Bupivacaine

(greater affinity for Na+ channels and remains at receptors for longer, makes resuscitation more difficult, higher CV morbidity)

23
Q

Rate the LAs on difficulty of cardiac resuscitation

A

Bupivacaine > Levobupivacaine > Ropivacaine > Lidocaine