Anesthesia Overview Quiz

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Questions and Answers

What is the primary risk associated with general anesthesia?

It does not affect breathing during surgery.

It often leads to prolonged memory loss.

It is most likely to cause side effects. (correct)

It guarantees no postoperative complications.

Which condition significantly increases the risk of complications during anesthesia?

Slight anxiety about surgery

History of mild colds

Minor headaches

Allergies to anesthesia (correct)

What is the safest type of anesthesia?

Sedation anesthesia

General anesthesia

Local anesthesia (correct)

Regional anesthesia

What common side effect might occur after general anesthesia?

Nausea and vomiting Signup and view all the answers

Which of the following conditions does NOT typically increase anesthesia risk?

Previous successful surgeries Signup and view all the answers

Inhaled anesthetics are measured by which parameter?

Partial pressure or 'Tension' in inspired air Signup and view all the answers

What factor does NOT influence the selection of an anesthetic technique?

Cost of procedure Signup and view all the answers

Which demographic is more likely to experience postoperative cognitive dysfunction?

Older people Signup and view all the answers

What effect does pregnancy have on the minimum alveolar concentration (MAC) of anesthetics?

Decreases MAC due to elevated progesterone Signup and view all the answers

Which inhalational anesthetic is recognized for its rapid onset and recovery, making it suitable for outpatient surgery?

Desflurane Signup and view all the answers

What potential risk is associated with prolonged exposure to nitrous oxide?

Megaloblastic anemia due to Vitamin B12 deficiency Signup and view all the answers

How do inhaled anesthetics differ in terms of metabolism?

Halothane is significantly metabolized, while desflurane is minimally metabolized Signup and view all the answers

What is the mechanism by which general anesthetics can cause nausea and vomiting?

By affecting the chemoreceptor trigger zone and brainstem centers Signup and view all the answers

What role does neostigmine play in conjunction with atropine during the postoperative period?

To reverse neuromuscular block Signup and view all the answers

Which statement best describes the effects of chronic alcohol use on the minimum alveolar concentration (MAC)?

Chronic alcoholics undergo cross-tolerance, resulting in increased MAC Signup and view all the answers

What is a common effect of inhaled anesthetics on the heart?

Sensitization of the heart to catecholamines, leading to arrhythmias Signup and view all the answers

Which of the following is true regarding the speed of induction of general anesthesia?

Ventilation rate influences the speed of induction. Signup and view all the answers

What is an important use of opioids such as remifentanil in anesthesia?

To minimize hemodynamic changes from painful stimuli. Signup and view all the answers

Which characteristic of nitrous oxide makes it suitable for use in dentistry?

It produces rapid recovery and has a good safety profile. Signup and view all the answers

Which of the following anesthetic agents can cause marked hypotension?

Propofol Signup and view all the answers

What does the plasma half-life of a drug indicate?

The time required for the drug concentration to be reduced by half. Signup and view all the answers

What is a common side effect of high doses of opioids in anesthesia?

Chest wall rigidity Signup and view all the answers

Which of these inhalational anesthetics is commonly known as 'laughing gas'?

Nitrous oxide Signup and view all the answers

Why should caution be exercised when administering barbiturates like thiopental?

They are respiratory and circulatory depressants. Signup and view all the answers

Study Notes

Hypoxia during anesthesia

Hypoxia during anesthesia can be caused by problems in the lungs, inadequate oxygen delivery to tissues, and impaired oxygen utilization.
Free radical generation can occur due to hypoxia.

Inhaled Anesthetics

Inhaled anesthetics are easily vaporized liquid halogenated hydrocarbons.
They are administered as gases.
Minimum Alveolar Concentration (MAC) is the minimum concentration of an anesthetic in the alveoli required to prevent a response to a painful stimulus in 50% of patients.

MAC & Patient Condition

MAC varies depending on patient factors.
Pregnancy decreases MAC due to elevated progesterone levels.
Elderly patients have decreased MAC due to less brain activity.
Chronic alcoholics have increased MAC due to cross-tolerance.
Acute alcoholic poisoning decreases MAC due to an additive effect.

Bispectrality Index monitor

The bispectrality index monitor uses electroencephalography (EEG) to measure a patient's anesthetic depth.
Anesthesia is typically terminated by redistribution of the drug from the brain to the blood and then out through the lungs.
Halothane and methoxyflurane undergo hepatic metabolism.

Properties of Inhaled Anesthetics

Desflurane and Sevoflurane have very low blood-gas coefficients, leading to rapid onset and recovery.
Desflurane and Sevoflurane are commonly used for outpatient surgery.
Desflurane and Sevoflurane are non-irritating to the airways.
Sevoflurane is a useful induction agent, particularly for children.
Isoflurane has a medium onset of action and recovery.
Isoflurane is used for induction and maintenance of anesthesia.
Isoflurane was previously the most common inhaled anesthetic but has been largely replaced by desflurane.

Halothane

Halothane undergoes more than 40% hepatic metabolism.
Rare cases of postoperative hepatitis can occur with halothane use.
Halothane can sensitize the heart to epinephrine, increasing the risk of arrhythmias.

Methoxyflurane

Fluoride release during methoxyflurane metabolism can lead to renal insufficiency after prolonged exposure.

Nitrous Oxide

Prolonged exposure to nitrous oxide can cause megaloblastic anemia due to decreased methionine synthase activity (Vitamin B12 deficiency).

NMJ Blockers

There are two types of NMJ blockers: depolarizing agents and non-depolarizing agents.
Succinylcholine is a depolarizing agent.
Curare-type drugs (e.g., atracurium) are non-depolarizing agents.
NMJ blockers relax skeletal muscles, facilitate intubation, and ensure immobility.
Neostigmine and glycopyrrolate are used to reverse the effects of non-depolarizing agents during the postoperative period.

Nausea and Vomiting

General anesthetics can affect the chemoreceptor trigger zone and brainstem vomiting center, causing nausea and vomiting.

Why Neostigmine is Given with Atropine

Neostigmine is given with atropine to counteract the bradycardia effect of neostigmine.

Speed of Induction of General Anesthesia

The speed of induction depends on the inspired gas partial pressure (anesthetic concentration), ventilation rate, and anesthetic solubility.
Less soluble anesthetics equilibrate more quickly with the blood and reach tissues like the brain faster.

Opioids

Opioids (morphine, fentanyl, remifentanil) provide analgesia.
General anesthetics do not produce effective analgesia (except for ketamine).
Opioids are given before surgery to minimize hemodynamic changes caused by painful stimuli and reduce anesthetic requirements.
High doses of opioids can cause chest wall rigidity and postoperative respiratory depression.
Therapeutic doses of opioids can inhibit respiration and lead to increased carbon dioxide levels.

Half-life of a Drug

The duration of action of a drug is known as its half-life.
The half-life refers to the time required for the concentration or amount of a drug in the body to be reduced by half.
Plasma half-life is the time required for the plasma concentration of a drug to decrease by half.

Classification of General Anesthetics

Intravenous anesthetic agents:
- Primarily used for induction
- Examples:
  - Barbiturates (thiopental, methohexital)
  - Benzodiazepines (midazolam, lorazepam)
  - Propofol
  - Thiopental (pentothal)
- Barbiturates are respiratory and circulatory depressants.
Total Intravenous (Maintenance) Anesthesia
- Example:
  - Propofol
Inhalational Agents
- Primarily used for maintenance of anesthesia
- Examples:
  - Inhalational Gases
    - Nitrous oxide (N2O)
    - Xenon
  - Volatile Agents

Therapeutic Gases

Oxygen:
- Administered to prevent hypoxic injury.
Anesthetic technique selection:
- Based on pre-operative examination, clinical evaluation, the type and extent of surgery, and the anesthesiologist's experience and equipment/drug availability.

Factors That Increase Anesthesia Risk

Allergies to anesthesia or a history of adverse reactions to anesthesia.
Diabetes.
Heart disease (angina, valve disease, heart failure, or a previous heart attack).
High blood pressure.
Kidney problems.
Lung conditions (asthma and chronic obstructive pulmonary disease, or COPD).
Obesity.
Obstructive sleep apnea.

Risks of Anesthesia

General anesthesia can cause unconsciousness and may have side effects and risks.
Most common side effects are minor and temporary (e.g., nausea, vomiting, chills, confusion, sore throat).
Serious risks associated with anesthesia are rare but can include:
- Postoperative delirium or cognitive dysfunction.
- Breathing problems during and after surgery.
- Unfavorable reaction to anesthesia (e.g., allergic reaction).
- Heart problems (e.g., heart attack, stroke).
- Death.

Risks Associated with Different Types of Anesthesia

Local anesthesia is the safest type, with rare side effects like pain or itching at the injection site.
Regional anesthesia, which numbs a larger part of the body, carries a slightly higher risk than local anesthesia.
- Potential risks include:
  - Nerve damage.
  - Bleeding.
  - Infection.
  - Headache after spinal anesthesia.
General anesthesia is associated with the highest risk of complications but remains very safe and effective.

Inhaled Anesthetics and Partial Pressure

The partial pressure or "tension" of an inhaled anesthetic in inspired air is a measure of its concentration.

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Description

Test your knowledge on hypoxia during anesthesia, inhaled anesthetics, and the Minimum Alveolar Concentration (MAC). This quiz also covers the effects of patient conditions on MAC and the use of the Bispectrality Index monitor in anesthesia. Perfect for medical students and anesthesia professionals.