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NSU AA Denver: Summer 2025 (2nd Semester) > Anesthesia Principles and Practice I: Lecture 2 - MAC/TIVA > Flashcards

Anesthesia Principles and Practice I: Lecture 2 - MAC/TIVA Flashcards

1
Q

What is Monitored Anesthesia Care (MAC)?

A

A sedation technique involving monitoring, support of vital functions, and treatment of physiological derangements by an anesthesia provider.

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2
Q

What is administered in MAC?

A

Sedative, anxiolytic, and/or analgesic medications.

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3
Q

What is the anesthetic choice for 1/3 ambulatory anesthetics for diagnostic/therapeutic procedures?

A

MAC, many of these are outside of an operating room.

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4
Q

Where is MAC commonly used?

A

One-third of ambulatory anesthetics, often outside the OR for diagnostic or therapeutic procedures such as GI Suite (EGD/Colonoscopy), Ophthalmology, vascular, combined with regional/neuraxial.

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5
Q

What is another term for MAC?

A

Twilight Sleep, psychological support and physical comfort.

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6
Q

Who can provide MAC?

A

Must be provided by personnel capable of converting to general anesthesia if needed.

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7
Q

What are preop requirements for MAC?

A

Same as general anesthesia—PMH, physical and airway exam.

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8
Q

What are contraindications for MAC?

A

Inability to lie flat, persistent cough, movement disorders, cognitive dysfunction, language/hearing barriers, inability to cooperate.

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9
Q

What conditions increase risk of aspiration, therefore concern for MAC?

A
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10
Q

Preop Airway Eval

A
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11
Q

What qualities must a MAC patient have?

A

Must be able to communicate, lie flat, and remain motionless without deep sedation. R/O are persistent cough, orthopnea, movement disorder

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12
Q

What patient cooperation concerns are there with MAC?

A

Cognitive dysfunction, dementia, extreme anxiety, language barrier/hearing deficit.

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13
Q

Must the patient be able to communicate with a care provider during MAC?

A

Yes, to assess depth of anesthesia, explain goings on, and provide reassurance.

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14
Q

What distinguishes MAC from moderate sedation?

A

MAC involves deeper sedation, readiness for conversion to GA, and management of adverse events.

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15
Q

What are provider responsibilities under MAC?

A

Exclusive focus on airway, hemodynamics, sedation depth, and adverse responses.

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16
Q

Does MAC provide amnesia?

A

Not always—patients may remember parts or all of the procedure.

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17
Q

MAC vs CS: What is the key difference?

A

Moderate (Conscious) sedation is not expected to induce depths of sedation that would impair the patient’s own ability to maintain the integrity of his or her airway. Maximal depth of sedation in MAC > Moderate Sedation

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18
Q

What are post-procedure responsibilities in MAC beyond expectations of moderate sedation?

A
  • Assuring a return to full consciousness
  • Relief of pain
  • Management of adverse physiological responses or side effects from medications administered during the procedure
  • Diagnosis and treatment of co-existing medical problems.
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19
Q

What must a patient understand with MAC?

A

May be aware and remember some or all of a procedure performed under MAC; total lack of awareness and amnesia cannot be expected without GA.

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20
Q

Why is MAC preferred in some cardiopulmonary patients?

A

To avoid general anesthesia risks associated with compromised respiratory or cardiac status.

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21
Q

What standard monitors are used during MAC?

A
  • ECG
  • NIBP q5min
  • Pulse oximetry
  • Temperature
  • Capnography.
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22
Q

Why is capnography important in MAC?

A

Helps detect apnea or airway obstruction early.

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23
Q

What are signs of oversedation under MAC?

A

Unarousable to painful stimulus—means patient has transitioned to GA, diaphoresis, pallor, shivering, cyanosis, and acute neurological changes

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24
Q

What monitors might you consider with MAC?

A

Processed electroencephalography may consider use of bis, SedLine, etc.

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25
What equipment is essential for MAC?
* Standard ASA monitors * Oxygen delivery * Warming devices * Infusion pumps.
26
What is a safety concern with oxygen use during MAC?
Increased risk of OR fire during head/neck procedures with electrocautery—keep FiO2 <30%.
27
What is the onset and duration of midazolam?
Onset 1-3 min, peak at 5 min, half-life 1-4 hours.
28
What are risks of midazolam?
Possible prolonged psychomotor impairment and enhanced sedation when mixed with opioids.
29
What are issues with Versed as a sole agent?
Patient still likely to move, prolonged amnesia.
30
What is the reversal agent for midazolam?
Flumazenil (Romazicon®), 0.2 mg over 15 sec, can repeat q min up to 1 mg max 3 mg/hr.
31
What is the Peds Min/Max dose of Flumazenil?
Peds min/max dose 0.01 mg/kg and 0.05 mg/kg.
32
What are benefits of propofol in MAC?
* Rapid onset/offset * Antiemetic * Modest amnesia * Quick recovery.
33
What is the dosage of propofol in MAC?
Can either bolus (10-30 mg) or start infusion (25-75 mcg/kg/min).
34
What are common side effects of propofol?
Pain on injection (70%), respiratory depression at higher doses.
35
How can pain from propofol injection be minimized?
Lidocaine injection before or mixed with propofol.
36
What are characteristics of fentanyl for MAC?
Onset 1-3 min, peaks in 6 min, DOA 30–60 min, used in 25–50 mcg boluses.
37
What is remifentanil’s key property?
Ultra-short acting with a context-sensitive half-time of ~3 minutes regardless of infusion time.
38
What are the dosages of Ultiva?
* Bolus- 1 mcg/kg over 30-90 seconds before LA infiltration * Infusion- 0.05-0.1 mcg/kg/min 5 min before LA infiltration.
39
Why use caution with remifentanil in MAC?
High risk of nausea, respiratory depression; difficult to titrate alone.
40
What are advantages of dexmedetomidine (Precedex)?
* Sedative * Anxiolytic * Analgesic * Antisialagogue * Minimal respiratory depression.
41
What is the dosage of Precedex?
Used either with or without a loading dose of 0.5-1 mcg/kg over 10 mins, 0.2-1.2 mcg/kg/hour.****Be careful not to set it to mcg/kg/min on a pump****
42
What are side effects of dexmedetomidine?
* Rapid admin may cause hypertension followed by Bradycardia * Hypotension * Slow onset * Variable recovery.
43
How does ketamine work in MAC?
Provides analgesia and amnesia with minimal respiratory depression.
44
What is the dosage of Ketamine?
0.25-0.5 mg/kg IV; hard to sedate patients may benefit from small doses to increase analgesia and decrease narcotics.
45
What are adverse effects of ketamine?
Emergence delirium, increased secretions (increased chance of laryngospasm), increased HR/BP.
46
What happens to the eyes during ketamine use?
Eyes remain open, may notice nystagmus.
47
When is the patient most stimulated during MAC?
Usually at the time of local anesthetic infiltration.
48
What causes agitation during MAC?
Hypoxia, hypercarbia, LAST, poor positioning, nausea, IV infiltration, etc.
49
What factors contribute to patient disinhibition with MAC?
Hypo/hyperthermia, pruritus, nausea, intolerance to positioning, IV infiltration, tourniquet pain, etc.
50
What considerations are there for procedures with minimal or no pain?
May give small doses of midazolam, precedex, or propofol; lack of access to airway may make GA with LMA/ett preferable.
51
Procedures with Brief Initial Pain?
Blocks, LA infiltration, femoral access for angiography: Midazolam 1-2 mg, fentanyl 50-100 mcg, and/or propofol 0.5-1 mg/kg over 1-2 minutes
52
Procedures with variable pain/discomfort throughout?
GI endoscopy, etc. Propofol bolus 0.5-1 mg/kg then propofol 25-100 mcg/kg/min Prn fentanyl 25-50 mcg or ketamine 0.5-1 mg/kg Consider dexmedetomidine infusion for patients with morbid obesity/sleep apnea
53
What is a typical MAC regimen for variable pain procedures?
Propofol bolus (0.5-1 mg/kg), infusion (25-100 mcg/kg/min), plus fentanyl or ketamine as needed.
54
What technique may reduce drug use but provide consistent plasma levels?
Infusion versus bolus—infusions provide steadier drug levels.
55
What is the most common MAC complication?
Respiratory depression due to oversedation. Overall rate of complications similar to GA.
56
What are specific mechanisms of injury for respiratory depression from oversedation?
* Hypoxemia * Hypercarbia * Aspiration from depressed airway reflexes * Hypotension * Cardiac ischemia/arrest * Arrhythmias * Complications secondary to patient movement * Burn injury from supplemental O2 and ignition source (electrocautery) near face.
57
What is LAST?
Local Anesthetic Systemic Toxicity.
58
What are signs of Low LAST?
* Sedation * Tongue and circumoral numbness * Metallic taste in mouth.
59
What are signs of Medium LAST?
* Restlessness * Vertigo * Tinnitus * Difficulty focusing.
60
What are signs of High LAST?
* Slurred speech * Skeletal muscle twitching * Tonic-clonic seizure.
61
LAST and decreased CV Function/CO?
Will have lower liver perfusion and therefore decreased LA metabolism
62
How does hypoventilation lead to toxicity?
Hypoventilation = Hypercarbia = more acidic = intracellular ion trapping = toxicity.
63
What increases CV toxicity?
Hypercarbia, hypoxia, acidosis, hyperkalemia.
64
How does LA affect cardiac muscle?
LA may block sodium channels in cardiac muscle during systole Bupivacaine dissociates slower in diastole making it more cardiotoxic Still many sodium channels blocked at the end of diastole
65
How does hypercarbia contribute to LAST?
It increases CBF and LA delivery to the brain, worsening toxicity.
66
How is LAST treated?
* Airway management * Oxygen * Benzos or propofol for seizures * Lipid emulsion therapy (1-1.5 ml/kg).
67
What is TIVA?
Total intravenous anesthesia—entire anesthetic delivered using IV medications.
68
What are advantages of TIVA?
* No airway gases * Useful in MH risk * Less PONV * Better for spine/neuromonitoring * Portable * No scavenging needed.
69
What types of surgeries is TIVA generally used for?
Airway/ENT surgery or pulmonary surgery.
70
Is TIVA useful for spine surgery?
Yes, has less effect on evoked potentials than volatile agents. MEP (motor evoked potentials) more sensitive than SSEP (somatosensory evoked potentials) High doses of propofol can still produce burst suppression/electrical silence
71
What are disadvantages of TIVA?
* Higher cost * Risk of IV infiltration * Respiratory depression (dose dependent) * Difficult monitoring of drug levels * Incorrect programming can deliver subanesthetic or overdose of medication.
72
TIVA and monitoring the IV limb?
The limb receiving the IV anesthetic may not visible or accessible Unrecognized IV infiltration could result in compartment syndrome Unrecognized disconnection not delivering anesthesia
73
Why is BIS monitoring helpful in TIVA?
Helps titrate depth of anesthesia to avoid under/overdosing.
74
What is the typical propofol infusion range for TIVA?
75–150 mcg/kg/min (lower in elderly or low cardiac output, may need more in healthy young patient or those with a cross tolerance)
75
How is remifentanil dosed for TIVA?
* Induction: 0.5–1 mcg/kg * Maintenance: 0.1–0.25 mcg/kg/min.
76
What opioid may be used for long TIVA cases?
Sufentanil: 0.2–1 mcg/kg/hr.
77
What long-acting opioids can be given before emergence?
Hydromorphone (0.25-0.5 mg) or morphine (2.5-5mg), 20-30 min or longer before emergence if significant post-op pain is expected.
78
How can lidocaine be used during TIVA?
1–2 mg/kg/hr infusion (lean body weight) Mixed reviews on postop pain control Potentially decreases airway reactivity during head and neck procedures Comparatively inexpensive
79
What are the advantages of NMB and TIVA?
May allow for lower insufflation pressures with laparoscopy and may reduce total dose of anesthetics as it prevents patient movement.
80
When should NMBAs be avoided in TIVA?
In spine cases where motor evoked potentials (MEPs) are monitored.
81
What are disadvantages of NMBA use during TIVA?
* Potential increase in risk of awareness under anesthesia * Residual blockade associated with morbidity and mortality * Relatively high incidence of allergic reaction. * Can’t be given in spines when motor evoked potentials are being monitored

NSU AA Denver: Summer 2025 (2nd Semester) (12 decks)

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