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AP 1 > Test 1 part V (CM) > Flashcards

Test 1 part V (CM) Flashcards

1
Q

Electrical potentials that are measured in response to a particular type of stimulus.

A

Evoked Potentials (EP)

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2
Q

Used to guide the surgical strategy and to act as a warning of neurologic deficits to prevent irreversible damage.
-Brainstem Auditory (BAEP), visual (VEP), motor (MEP), and somatosensory (SSEP) stimuli are commonly used.

A

Evoked Potentials

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3
Q

Changes in EP response may indicate ______.

A

Injury

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4
Q

Injuries to neural structures (that cause a change in EP) can arise from what?

A
  1. Heat (ECU)
  2. Mechanical Stress (Retraction)
  3. Ischemia (ligation, edema, and vessel damage)
  4. Loss of functional integrity (transection)

Also, can be affected by hypothermia, hypotension, positioning, and anemia (and medications we give).

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5
Q

What is the key to reducing serious complications when monitoring EPs?

A

Early Detection!!

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6
Q

What are the three components of the EP waveform that are examined?

A
  1. General Appearance
  2. Amplitude (the intensity of the evoked response)
  3. Latency (the time necessary for the evoked response to be measured in the brain).
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7
Q

A ____ decrease in amplitude or a ___ increase in latency is suggestive of the possibility of ________, and the surgical team should be made aware of this change.

A

50%; 10%; cerebral ischemia

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8
Q

When would you use Brainstem Auditory Evoked Potentials (BAEPs)?

A

Brain surgery at or near brainstem, or for acoustic neuroma resection (pediatrics)

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9
Q

Can you use sedation with Visual EPs?

A

No, most sensitive to anesthetic agents and difficult to monitor

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10
Q

Used to monitor the integrity of the neural structures along both the peripheral and central somatosensory pathways of the brain and spinal cord.

A

Somatosensory Evoked Potentials (SSEPs)

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11
Q

What induces a Somatosensory Evoked Potential (SSEP)?

A

Stimulation of a peripheral nerve (mixed motor/sensory nerve)

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12
Q

The lower extremities are SSEP monitored using which nerve?

A

Posterior Tibial Nerve

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13
Q

The upper extremities are SSEP monitored using which nerve?

A

Median Nerve

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14
Q

What are the indications for SSEP monitoring?

A
  1. Neurosurgical procedures (cerebral aneurysm & spine)
  2. Aortic cross clamping
  3. CEA with shunting
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15
Q

Most anesthetic agents _____ latency and _____ amplitude of SSEPs, except for _____, ______, and _____.

A

Increase; Decrease; ketamine, etomidate, and opioids.

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16
Q

Inhalational agents have a ____ depressant effect on EP waveforms compared to IV agents.

A

Greater depressant effect

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17
Q

What anesthetic technique is utilized in SSEP Monitoring?

A

Opioid based, TIVA, ½ MAC inhalation

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18
Q

Avoid which anesthetic with SSEP monitoring and why?

A

Avoid N2O because it potentiates depressant effects.

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19
Q

_____ & ____ increase cortical amplitudes and enhance the SSEP waveforms.

A

Etomidate and Ketamine

20
Q

Do NMBAs effect SSEP monitoring?

A

No, but you won’t get a motor response (MEP) -communicate with surgery team & neuromonitoring tech.

21
Q

Evoked potentials that are the gold standard for monitoring the integrity of motor tracts.

A

Motor Evoked Potentials (MEPs)

22
Q

What are the indications for monitoring of Motor Evoked Potentials (MEPs)?

A

Spine & Intracranial surgery where the motor cortex or descending motor pathways are at risk.

23
Q

What are the anesthetic techniques employed during monitoring of Motor Evoked Potentials (MEPs)?

A
  1. Opioid based, TIVA, 1/2 MAC
  2. Etomidate & ketamine increase cortical amplitudes and enhance MEP waveforms
24
Q

What anesthetic agents are avoided (contraindicated) with MEPs and why?

A
  1. Avoid N2O due to potentiation of depressant effects
  2. NMBAs are contraindicated because then no motor responses can happen
25
Q

Multimodal monitoring of what EPs is the standard for spinal surgery?

A

SSEPs and MEPs

26
Q

What EPs are the most susceptible to anesthesia?

A

VEP > SSEP > BAEP

27
Q

Monitors the patient’s level of consciousness (reduces incidence of awareness w recall).

A

Bispectral Index (BIS) Monitor

28
Q

Uses an algorithm that processes the patient’s EEG in real time and assigns it a value between 0-100, with 100 being awake and 0 being the absence of brain activity.

A

Bispectral Index (BIS) Monitor

29
Q

BIS _____ to ____ is adequate GA for surgery, and BIS <____ is a deep hypnotic state.

A

40 to 60 is adequate GA, and BIS <40 is a deep hypnotic state

30
Q

Refers to the supratentorial CSF pressure. Normal is 5-15 mmHg in adults.

A

Intracranial Pressure (ICP)

31
Q

Pressures exceeding _____ to ____ mm Hg are indicative of intracranial hypertension necessitating monitoring and treatment.

A

20-25 mm Hg

32
Q

How to calculate CPP?

A

CPP = MAP - ICP

33
Q

What are the determinants of ICP?

A

Brain, blood, intracellular water, and CSF

34
Q

The brain is enclosed in cranium & is not compressible, so any increase in total intracranial volume produces an accompanying increase in ICP.

Expansion in 1 compartment=decrease in another

A

Monro-Kelly Doctrine

35
Q

What are S/Sx of Increased ICP?

A

Headache, N/V, papilledema, focal neuro deficits, ventilatory dysfunction, altered LOC, seizures, coma

36
Q

What is Cushing’s Triad?

A
  1. HTN
  2. Bradycardia
  3. Irregular RR
37
Q

What occurs when ICP > 30 mmHg?

A

CBF progressively decreases, and a vicious cycle is established: ischemia produces brain edema, which in turn increases ICP, and further precipitates ischemia. If this cycle remains unchecked, progressive neurologic damage or catastrophic herniation may result.

38
Q

What is the treatment for Increased ICP?

A
  1. Insertion of an intracranial pressure monitor
  2. Optimize sedation & analgesia
  3. Open external ventricular drain for >20 mmHg (for 10 min)
  4. Hyperosmolar therapy (3% saline, mannitol)
  5. Hyperventilation
  6. Elevate HOB 15-30 degrees
  7. Avoid overhydration
  8. Optimize hemodynamics
  9. Surgical decompression
  10. Mild hypothermia
  11. Avoid corticosteroids
39
Q

What is the gold standard for monitoring of ICP?

A

Intraventricular catheter (infection risk)

40
Q

What is the leading cause of AKI in hospitalized patients?

A

Surgery

41
Q

Renal dysfunction without structural injury to the renal parenchyma.

A

Prerenal (40-70% of cases)

42
Q

Is prerenal kidney injury reversible?

A

Yes, correct underlying causes and increase renal perfusion

43
Q

Dysfunction d/t injury to the tubules, glomeruli, interstitium, & intrarenal blood vessels —may result from untreated pre/post causes & nephrotoxins.

A

Renal (25% of cases)

44
Q

What is the treatment for “Renal” Kidney injury?

A

Treat underlying causes and prevent toxic exposure

45
Q

Dysfunction d/t acute obstruction to urinary flow

A

Postrenal (5% of cases)

46
Q

What is the treatment for “postrenal” Kidney injury?

A

Relieve the obstruction

47
Q

What are the Renal Protective Strategies?

A
  1. Goal-directed fluid therapy
  2. Use Balanced Isotonic crystalloid solutions (avoid 0.9% NaCl d/t hypochloremia dec RBF & HES solutions)
  3. Hemodynamic stability within autoregulation limits (MAP 80-160)
  4. Correct anemia & minimize blood transfusions
  5. Avoid nephrotoxins (aminoglycosides, vancomycin, contrast dye)
  6. Avoid diuretics
  7. Continue statin therapy
  8. Maintain normoglycemia
  9. Consider low-dose precedex & sodium bicarb
  10. Dexamethasone
  11. Early initiation RRT
  12. Hold Meds Pre-op: ACE-I, ARB, NSAIDS, diuretics
  13. Ensure adequate volume status, cardiac performance, systemic perfusion
  14. Urine output > 0.5 mL/kg/hr

AP 1 (32 decks)

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