Chapter 7 Flashcards

1
Q

Who gave the first public demonstration of general anesthesia at Mass Gen?

A

William T.G. Morton on October 16, 1846

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2
Q

What are the “A”s of anesthesia?

A
Amnesia
Anesthesia
Analgesia
Akinesia
Areflexia
Anxiolysis
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3
Q

Amnesia

A

Inability to form memories

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4
Q

Anesthesia

A

Lack of sensation

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5
Q

Analgesia

A

Relief/lack of perception of pain

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6
Q

Akinesia

A

Lack of movement in response to surgical stimulus

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7
Q

Areflexia

A

Blunting of autonomic reflexes- attenuation of reflexic hemodynamic responses to surgical stimulus

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8
Q

Anxiolysis

A

Decrease in procedure-related anxiety

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9
Q

What does the preoperative assessment include?

A

Detailed hx
PE
Review of pertinent data and studies

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10
Q

What are the advantages of a preoperative assessment?

A

Allows further studies to be performed, if indicated

Allows interventions to take place so that the pt may be “optimized”

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11
Q

What is the goal of the preoperative assessment?

A

Summarize the pt’s status to formulate an anesthetic plan

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12
Q

Which active cardiac conditions should be evaluated and treated before noncardiac surgery?

A

Decompensated heart failure
Severe valvular disease
Significant arrhythmias
Unstable coronary syndromes

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13
Q

What procedures are considered to have elevated cardiac risk?

A
Aortic and other major vascular
Peripheral vascular
Anticipated prolonged surgical procedures associated with large fluid shifts and/or blood loss
Carotid endarterectomy
Head and neck
Intraperitoneal and intrathoracic
Orthopedic 
Prostate
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14
Q

What procedures have a low cardiac risk?

A

Cataract

Plastic surgery

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15
Q

What are five clinical predictors of cardiac risk independent of the surgical procedure?

A
Ischemic heart dz
Hx of heart failure
Cerebrovascular dz
Diabetes mellitus
Renal insufficiency
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16
Q

When is perioperative cardiac morbidity increased?

A

In those unable to achieve four METs

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17
Q

What is more predictive of perioperative outcomes than spirometry?

A

Clinical findings and pt exercise capability

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18
Q

In evaluation of the pulmonary system, what diseases should be inquired about?

A
Reactive airway dz
COPD
Tobacco use
Oxygen requirement
Obstructive sleep apnea sx
Recent upper respiratory tract infections
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19
Q

Who is at increased risk of pulmonary complications?

A

FEV1 <70%

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20
Q

When is the highest likelihood of gastric aspiration?

A

Induction

Emergence

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21
Q

When is aspiration more likely during the maintenance phase of anesthesia?

A

If the airway is not protected intraoperatively with an ET tube

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22
Q

What must be in place during heavy sedation?

A

ET tube

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23
Q

What are specific risk factors for aspiration during surgery and anesthesia?

A
Recent ingestion of food (<8 hrs for heavy meals, <6 h for light solid food, <2 h for clear liquids)
Trauma
Gi dysfunction
Increased intra-abdominal pressure
Use of opioids
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24
Q

When does the ACC/AHA recommend continuing beta blockers?

A

HTN
Angina
Symptomatic arrhythmias

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25
Q

When does the ACC/AHA recommend starting beta blockers?

A

Those undergoing vascular surgery who were found to have ischemia on preoperative testing

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26
Q

What does LEMON stand for?

A
Look externally
Evaluate the 3-3-2 rule
Mallampati
Obstruction
Neck mobility
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27
Q

What in the look externally part of LEMON would make for a more difficult intubation?

A
Known face or neck pathology
Abnormal face shape
Sunken cheeks
Receding mandible
Narrow mouth
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28
Q

In the 3-3-2 rule, what would make for a more difficult intubation?

A

Mouth opening <3 fingers
Hyoid-chin distance <3 fingers
Thyroid cartilage-mouth floor distance <2 fingers

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29
Q

What obstruction can cause a difficult airway?

A

Pathology within and/or around the upper airways (e.g., epiglottis, abscess, etc.)

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30
Q

What are predictors of difficulty with ventilation?

A
Obesity
Presence of beard
Edentulousness
Presence of OSA sx
Advanced age
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31
Q

Possible effects of diuretics on anesthetic course during surgery

A

Hypovolemia and hypotension

Electrolyte abnormalities and ECG changes

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32
Q

Possible effects of ACE inhibitors, certain aniarrhythmics on anesthetic course during surgery

A

Refractory vasodilation and hypotension

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33
Q

Possible effects of antiplatelet agents, anticoagulant agents on anesthetic course during surgery

A

Possible increased blood loss

Increased risk of epidural hematoma formation on epidural catheter placement or removal

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34
Q

Possible effects of insulin, oral hypoglycemics on anesthetic course during surgery

A

Hypoglycemia, altered level of consciousness

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35
Q

What are the possible effects of MAO inhibitors on anesthetic course during surgery?

A

Life-threatening HTN or hyperthermia when used with sympathomimetics or meperidine

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36
Q

Clinical indicators for ordering an EKG

A
Age 50 or older
Significant cardiocirculatory dz, current or past
DM (age 40 or older)
Renal dz
Other major metabolic dz
Procedure level 5
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37
Q

Clinical indicators for CXR

A

Asthma or COPD that is debilitating or with change of sx or acute episode within past 6 mos
Cardiothoracic procedure
Procedure level 5

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38
Q

Clinical indicators for serum chemistries

A
Renal dz
Adrenal or thyroid disorders
Diuretic therapy
Chemo
Procedure level 5
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39
Q

Clinical indicators for UA

A
DM
Renal dz
Genitourologic procedure
Recent GU infection
Metabolic d/o involving renal function
Procedure level 5
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40
Q

Clinical indicators for CBC

A

Hematologic d/o
Vascular procedure
Chemo
Procedure level 4

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41
Q

Clinical indicators for coagulation studies

A

Anticoagulation therapy
Vascular procedure
Procedure level 5

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42
Q

Clinical indicators for pregnancy test

A

Pts for whom pregnancy might complicate the surgery

Pts of uncertain status by hx

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43
Q

Definition of procedure 4

A

Highly invasive procedure with blood loss >1500 mL

Includes major ortho surgery, reconstruction of the GI tract, and vascular repair without an ICU stay

44
Q

Definition of procedure 5

A

Similar to procedure 4 except with ICU stay with invasive monitoring

45
Q

What are the standard intraoperative monitors for virtually all anesthetics?

A
Pulse oximeter
Noninvasive BP monitoring
ECG
Temp monitor
A means of assessing adequacy of ventilation, usually with an end-tidal CO2 monitor
46
Q

What is the gold standard to monitor endotracheal intubation?

A

EtCO2

47
Q

EtCO2 is how much below arterial CO2?

A

5-6 mm Hg

48
Q

An increase in the gap of CO2 between the lungs and arteries in the extreme occurs during what two events?

A

PE

Cardiac arrest

49
Q

What can be detected by a delayed upstroke of the EtCO2 tracing?

A

An obstruction to expiration, such as bronchospasm

50
Q

Which nerve is usually tested in peripheral nerve stimulation when paralytic agents are used?

A

Ulnar

51
Q

What is the purpose of the intra-arterial catheter?

A

Helpful for frequent blood gas and electrolyte monitoring

52
Q

What is the purpose of the central venous pressure monitor?

A

Surrogate of the Left Ventricular End Diastolic Pressure to monitor intravascular volume

53
Q

What is the purpose of the pulmonary artery catheter

A

More accurate measurement of LVED volume

54
Q

In addition to anesthesia, what else occurs during the induction phase?

A

Pt is prexoygenated, or denitrogenated, with 100% oxygen delivered from a face mask with as tight of a seal as possible

55
Q

What is the goal of preoxygenation?

A

Bring the end-tidal concentration of oxygen >80% with an SaO2 of 100%

56
Q

What is the MOA of most IV agents?

A

Facilitate GABA pathways in the brain?

57
Q

What are some examples of IV agents?

A
Barbiturates
Propofol
Etomidate
Ketamine
Benzos
58
Q

What is the most common induction agent currently used in the US?

A

Propofol

59
Q

When should propofol be used with caution?

A

Pts with low cardiac reserve

60
Q

What is an additional benefit of propofol?

A

Antiemetic properties

61
Q

When should etomidate be used?

A

In pts with compromised hemodynamics

62
Q

What is a side effect of etomidate?

A

Can suppress adrenal hormone synthesis for up to 5-6 hrs

63
Q

What are benzos usually combined with?

A

Opiods

64
Q

Why do benzos need to be used in combination with something else?

A

They have no analgesic properties

65
Q

What is the predominant benzodiazepine used?

A

Midazolam

66
Q

How can overdose of benzos be treated?

A

Flumazenil

67
Q

MOA of ketamine

A

Inhibits thalamocortical pathways and activation of the limbic system

68
Q

When should ketamine be used?

A

Induction of anesthesia in pts who must maintain spontaneous breathing, pts with reactive airway dz
Can be used as an adjunct in pts with chronic pain

69
Q

When is ketamine undesirable?

Relatively contraindicated?

A

Head injury and/or elevations in ICP

Coronary artery dz or uncontrolled HTN

70
Q

What can be used to decrease the complications of dysphoria and hallucinations in ketamine?

A

Benzos

71
Q

When are opioids ideal adjuncts?

A

For pts with compromised cardiac function undergoing cardiac surgery

72
Q

MOA of opioids

A

Interact with opioid receptors in the CNS and mediate effects on pain, mood, respiration, circulation and bowel and bladder function

73
Q

What are the side effects of opioids?

A

Direct dose-dependent depression of ventilation
Slowed peristalsis and delayed gastric emptying
N/V
Constipation
Urinary retention
Morphine and meperidine- histamine release, causing flushing and hypotension

74
Q

What is the standard measure of potency for inhaled anesthetics?

A

The minimum alveolar concentration (MAC) of a given gas at 1 atmosphere that produces immobility in 50% of subjects exposed to a noxious stimulus

75
Q

What are the inhalational agents commonly used today?

A

Isoflurane
Sevoflurane
Desflurane

76
Q

Which inhalational agent is the most insoluble agent in the blood, thereby allowing a very quick onset and offset of anesthesia?

A

Desflurane

However, it is relatively unsuitable for mask inductions

77
Q

What do volatile anesthetics cause?

A
Dose-dependent cardiac depression
Decreases in systemic, pulmonary, and venous vascular resistance
Respiratory depression
Bronchodilation
Decreases in CMRO2
Increases in ICP
78
Q

When is sevoflurane use ideal?

A

Mask induction, especially in peds or in pts without IV agents

79
Q

Use of nitrous oxide

A

Used only as an adjuvant anesthetic at relatively high inspired concentrations

80
Q

When is nitrous oxide contraindicated?

A

Pneumo
Small bowel obstruction
Air embolism
Middle ear surgery

81
Q

What are the two major classes of NMB agents?

A

Depolarizing and

Nondepolarizing agents

82
Q

What is the only depolarizing agent used in the US?

A

Succinylcholine

83
Q

What are the major advantages of succinylcholine?

A

Rapid onset
provisiono f reliable intubating conditions in 60 secs
Duration of action of 3-5 mins

84
Q

What are the adverse effects of succinylcholine?

A

Release of potassium from muscle- could lead to life-threatening hyperkalemia
Malignant hyperthermia

85
Q

What pts are susceptible to life-threatening hyperkalemia d/t succinylcholine use?

A

Pts with extensive burns
Massive tissue injuries
Neurologic injuries
Neuromuscular d/os

86
Q

What are relative contraindications to succinylcholine?

A

Pts with intracranial HTN or open orbital injuries

Children

87
Q

What is used to maintain fluids?

A

Isotonic crystalloids administered at approximately 2 mL/kg/hr

88
Q

How is blood loss replaced?

A

Crystalloid or colloids until transfusion is necessary

89
Q

How should nondepolarizing NMB agents be reversed?

A

Acetylcholinesterase inhibitors

90
Q

What else should be given to reverse nondepolarizng NMB agents?

A

Anticholinergics, otherwise reversal will result in severe bradycardia and possible asystole

91
Q

What must a pt be able to do before extubation?

A

Breathe on their own
Follow commands
Demonstrate purposeful movements
Protect their airway

92
Q

What are objective criteria for extubation?

A

Resonable RR (>8 and <30)
Adequate tidal volume (<5 mL/kg)
PaCO2 <50 mm Hg
Hemodynamic stability

93
Q

When does neuraxial anesthesia result in higher rates of graft viability?

A

Peripheral revascularization
Decreased intraoperative blood loss
Lower rate of DVT for hip surgery

94
Q

What are some systemic implications of neuraxial anesthesia?

A
Bradycardia
Hypotension
Mental status changes
Postdural HA
Epidural hematoma, more likely in pts with increased ICP
95
Q

How to treat hypotension as a result of neuraxial anesthesia

A

Fluid administration
Vasoconstrictors
Inotropic agents

96
Q

How to treat bradycardia as a result of neuraxial anesthesia

A

Anticholinergics

97
Q

How to treat postdural puncture HA

A

Bed rest
IV hydration
Caffeine
If conservative measures fail, epidural blood patch

98
Q

What are two infectious complications of neuraxial anesthesia?

A

Epidural abscess

Meningitis

99
Q

Sx of epidural hematoma

A

Backache

LE weakness or numbness

100
Q

What must be continued prior to neuraxial anesthesia?
How long?
Why?

A

Ticlopidine- 2 wks prior
Clopidogrel- 1 wk prior
Increased risk of hematoma

101
Q

Advantages of peripheral nerve blocks over neuraxial blocks

A

Greater neuraxial stability

Less risk of neurologic injury

102
Q

Complications of peripheral nerve block

A

Hematoma
Block failure
Intravascular injection
Nerve damage

103
Q

Possible complication of intercostal, interscalen, supra-or infraclavicular nerve block

A

Pneumo

104
Q

Complication of interscalene block

A

Phrenic nerve paralysis

105
Q

Relative contraindications to regional nerve blocks

A

Sepsis
Skin infection in area of proposed needle placement
Pre-existent neurologic deficit/neuropathy