14 Apr Local Anesthetics and Complications Pt3

Question 1

What are local anesthetics?

Answer 1

Medications used to induce a temporary loss of sensation in a specific area of the body.

Question 2

What does pKa represent in pharmacology?

Answer 2

The pH at which a drug is 50% ionized and 50% non-ionized, affecting its absorption and efficacy.

Question 3

What is systemic toxicity?

Answer 3

Adverse effects that occur when local anesthetics enter the systemic circulation, potentially leading to severe complications.

Question 4

Define Cauda Equina Syndrome.

Answer 4

A serious condition resulting from compression of the cauda equina, leading to sensory and motor deficits in the lower extremities.

Question 5

What is Methylene Blue used for?

Answer 5

A treatment for methemoglobinemia, a condition where hemoglobin is unable to carry oxygen effectively.

Question 6

List the key complications associated with local anesthetics.

Answer 6

• Allergic Reactions
• Systemic Toxicity
• Neural Tissue Toxicity
• Cauda Equina Syndrome
• Methemoglobinemia

Question 7

What should be done if an adverse reaction occurs during anesthesia?

Answer 7

Discontinue the causative agent immediately.

Question 8

What supportive care is provided during adverse reactions?

Answer 8

Provide airway support, oxygen, and IV fluids as needed.

Question 9

When should epinephrine be administered?

Answer 9

For anaphylactic reactions, to counteract severe allergic responses.

Question 10

What is the purpose of intralipid emulsion in the context of local anesthetic toxicity?

Answer 10

To sequester the anesthetic in cases of systemic toxicity.

Question 11

What is the importance of consulting specialists in anesthesia complications?

Answer 11

To refer cases of severe complications or when in doubt.

Question 12

What did seminal studies on lipid rescue therapy demonstrate?

Answer 12

The effectiveness of lipid emulsion in treating local anesthetic systemic toxicity.

Question 13

Which local anesthetic is most commonly associated with allergic reactions?

Answer 13

Lidocaine.

Question 14

What is the pKa of Drug B?

Answer 14

9.1

Question 15

What is the pKa of Drug W?

Answer 15

4.5

Question 16

Fill in the blank: Epinephrine concentration of _______ can decrease systemic absorption of local anesthetics by 1/3.

Answer 16

5 mcg/mL

Question 17

What is the maximum total dose of Intralipid for local anesthetic systemic toxicity?

Answer 17

10 mL/kg over the first 30 minutes.

Question 18

What common allergic reaction causes are associated with local anesthetics?

Answer 18

• PABA (para-aminobenzoic acid) in ester anesthetics

Question 19

What is the common dose for diphenhydramine (Benadryl) for allergic reactions?

Answer 19

50-100 mg

Question 20

True or False: Local anesthetic systemic toxicity (LAST) can occur due to excessive plasma levels of local anesthetics.

Answer 20

True

Question 21

What are the CNS effects of local anesthetics?

Answer 21

• Agitation
• Metallic taste
• Circumoral numbness
• Seizures

Question 22

What are the cardiovascular effects of local anesthetics?

Answer 22

• Hypotension
• Myocardial depression
• Dysrhythmias

Question 23

What is the first step in managing an allergic reaction to an anesthetic?

Answer 23

Stop the administration of the offending drug immediately.

Question 24

What is the role of corticosteroids in managing allergic reactions?

Answer 24

They may be administered depending on the severity of the reaction.

Question 25

What should be monitored during the administration of local anesthetics?

Answer 25

Vital signs and oxygen saturation.

Question 26

What is a common allergic reaction to local anesthetics characterized by rapid onset?

Answer 26

Anaphylaxis.

Question 27

What is the significance of monitoring plasma levels of local anesthetics?

Answer 27

To prevent toxicity.

Question 28

What is the effect of the diaphragm's position during anesthesia?

Answer 28

It can significantly affect Functional Residual Capacity (FRC).

Question 29

What is the typical starting dose of propofol?

Answer 29

1 ml (10 mg)

Question 30

What can cause circumoral numbness and skeletal muscle twitching?

Answer 30

Local Anesthetic Systemic Toxicity (LAST).

Question 31

Fill in the blank: The risk of LAST increases with the concentration and _______ of local anesthetic administered.

Answer 31

volume

Question 32

What does the term 'neural tissue toxicity' refer to?

Answer 32

Direct neurotoxic effects from high concentrations or direct injection into nerves.

Question 33

What is the pharmacological class of bupivacaine?

Answer 33

Local Anesthetic

Question 34

What is a common side effect of epinephrine in local anesthetic formulations?

Answer 34

Tachycardia

Question 35

What can excessive plasma levels of local anesthetics affect?

Answer 35

CNS and cardiovascular systems, leading to severe complications.

Question 36

What is the role of ultrasound guidance in administering local anesthetics?

Answer 36

Allows for more precise placement of local anesthetics, reducing the risk of complications.

Question 37

What is the effect of adding epinephrine to local anesthetics?

Answer 37

It can prolong the effects and reduce systemic absorption.

Question 38

What are the early signs of Local Anesthetic Systemic Toxicity (LAST)?

Answer 38

* Metallic taste * Circumoral numbness * Skeletal muscle twitching

Question 39

What is a common early sign of systemic toxicity from local anesthetics?

Answer 39

Circumoral numbness and skeletal muscle twitching ## Footnote These symptoms indicate potential toxicity and should be monitored closely.

Question 40

Which cardiovascular complications can occur due to local anesthetic toxicity?

Answer 40

Hypotension and myocardial depression ## Footnote These complications can lead to severe issues such as seizures.

Question 41

True or False: Pregnant patients are less vulnerable to local anesthetic toxicity.

Answer 41

False ## Footnote Pregnant patients are particularly vulnerable due to lower plasma esterases and proteins.

Question 42

What is the risk associated with high plasma concentrations of local anesthetics?

Answer 42

Increased risk of cardiovascular collapse ## Footnote This is especially significant when concentrations exceed 25 mics/ml.

Question 43

What is the first step in managing local anesthetic toxicity?

Answer 43

Stop the administration of the causative agent immediately ## Footnote This is critical to prevent further complications.

Question 44

Fill in the blank: The administration of _______ during cardioversion can lead to conduction delays.

Answer 44

lidocaine ## Footnote Lidocaine can cause dangerous conduction delays and potential cardiac arrest.

Question 45

What is the purpose of lipid emulsion therapy in cases of local anesthetic toxicity?

Answer 45

Aids in myocardial metabolism and binds local anesthetics ## Footnote This therapy facilitates metabolism and clearance from the system.

Question 46

What is the standard bolus for lipid emulsion therapy?

Answer 46

1.5 mL/kg of a 20% emulsion ## Footnote This should be administered rapidly over one minute.

Question 47

What type of interventions are recommended for the management of neural tissue toxicity?

Answer 47

Consultations with neurologists and neurosurgeons ## Footnote These consultations are critical for managing severe cases.

Question 48

What are Transient Neurologic Symptoms (TNS)?

Answer 48

Moderate to severe pain in the lower back and posterior thighs ## Footnote TNS typically resolves within 1 to 7 days.

Question 49

What is a significant risk factor for anterior spinal artery syndrome?

Answer 49

Hypotensive episodes or vascular compromise ## Footnote These factors can lead to ischemia and potential permanent damage.

Question 50

What is the consequence of direct injection of local anesthetics into nerves?

Answer 50

Significant neurotoxic effects ## Footnote This can lead to complications and increased risk of toxicity.

Question 51

True or False: The use of propofol is safe in hemodynamically unstable patients.

Answer 51

False ## Footnote Propofol is contraindicated due to its hypotensive effects.

Question 52

What is the recommended infusion rate after the initial bolus of lipid emulsion therapy?

Answer 52

0.25 mL/kg/min for at least 10 minutes ## Footnote This maintains therapeutic levels following the bolus.

Question 53

What can hyperkalemia lower in the context of local anesthetic toxicity?

Answer 53

Action potential threshold ## Footnote This increases the likelihood of seizures.

Question 54

What are some potential symptoms of local anesthetic toxicity?

Answer 54

Respiratory depression and lower respiratory rates ## Footnote These symptoms are central nervous system effects.

Question 55

What is the significance of patient history in assessing risks of local anesthetic reactions?

Answer 55

It informs the choice of anesthetic agents and techniques ## Footnote A thorough history minimizes risks and enhances patient safety.

Question 56

What is the maximum total dose of Intralipid for patients weighing 70 kg or more?

Answer 56

10 mL/kg within the first 30 minutes ## Footnote This updated guideline ensures safe administration.

Question 57

Fill in the blank: The clinical presentation of anterior spinal artery syndrome can vary based on the extent of _______.

Answer 57

vascular compromise ## Footnote The duration of ischemia also affects symptoms.

Question 58

What critical vital sign reading may indicate hypotension requiring immediate intervention?

Answer 58

Blood pressure of 70/35 ## Footnote This indicates severe hypotension that may necessitate treatment.

Question 59

What should be done if a patient exhibits severe hypotension or cardiac instability?

Answer 59

Immediate intervention with lipid emulsion therapy ## Footnote This is recommended to manage severe toxicity.