The General Anesthesia Quiz! Trivia

Minimal Alveolar Concentration (MAC) refers to the concentration of an inhalation anesthetic that is required to prevent 50% of the population from responding to a surgical stimulus, typically the scalpel. It is a measure of the potency of the anesthetic and is used to determine the appropriate dosage for patients undergoing anesthesia. The other options provided in the question do not accurately describe the concept of MAC.

Stage 3 of anesthesia is the best stage for surgery because it is characterized by a state of surgical anesthesia. In this stage, the patient is unconscious, has a stable and controlled level of anesthesia, and is able to undergo surgery without feeling pain or experiencing awareness. Stage 3 provides the optimal conditions for the surgical team to perform procedures safely and effectively.

The depth of anesthesia of inhalation anesthetics depends on multiple factors. The alveolar concentration of the agent is important because it determines the amount of the anesthetic reaching the alveoli and being available for gas exchange. The concentration of the agent in the inspired gas mixture is also significant as it affects the overall delivery of the anesthetic to the patient. The solubility of the agent in the blood plays a role in the rate of uptake and distribution of the anesthetic throughout the body. Finally, pulmonary blood flow, which is influenced by cardiac output, affects the removal of the anesthetic from the lungs. Therefore, all of the mentioned factors contribute to the depth of anesthesia.

Ether is not a parenteral anesthetic because it is administered through inhalation, rather than through injection or infusion. Parenteral anesthetics are those that are delivered directly into the bloodstream, bypassing the gastrointestinal tract. Propofol, thiopental, and ketamine are all examples of parenteral anesthetics as they are administered intravenously.

Propofol is the most commonly used parenteral anesthetic in the US because it has a rapid onset and short duration of action, making it ideal for procedures requiring sedation or general anesthesia. It also has a favorable side effect profile and is well-tolerated by patients. Additionally, propofol provides smooth induction and emergence, and its sedative properties allow for easy titration of the desired level of anesthesia. Therefore, propofol is preferred over other options such as ether, thiopental, ketamine, and etomidate in the US.

General anesthetics can have multiple effects on ion channels. Activation of a certain class of K+ channel can contribute to the overall effect of anesthetics by hyperpolarizing the membrane potential and reducing neuronal excitability. Increasing the sensitivity of GABAa receptors to GABA enhances inhibitory neurotransmission, leading to a sedative effect. Inhibiting excitatory current in NMDA receptors helps to reduce synaptic transmission and neuronal activity. Enhancing the action of glycine on glycine receptors also enhances inhibitory neurotransmission. Therefore, all of these actions can explain the effects of general anesthetics on ion channels.

The P4 plane or substage of anesthesia is characterized by intercostal muscle paralysis. This means that the muscles between the ribs are unable to contract or move, leading to impaired respiratory function. This can result in shallow breathing or even respiratory arrest if not managed properly. Intercostal muscle paralysis is an important aspect of anesthesia as it helps to ensure adequate ventilation and oxygenation during surgery or other procedures.

General anesthetics are available in various dosage forms, including intravenous, inhaled gases and volatile liquids, intramuscular, and intrarectal. However, oral administration is not a common route for general anesthetics. This is because oral administration may not provide the rapid onset and precise control of anesthesia that is required in surgical procedures. Therefore, general anesthetics are not typically available in oral dosage form.

The correct order of the stages of anesthesia is D, B, A, C. First, analgesia occurs, which is the stage where the patient experiences pain relief. Then, amnesia and irregular respiration occur, which refers to the loss of memory and changes in breathing patterns. After that, surgical anesthesia takes place, which is the stage where the patient is unconscious and feels no pain. Finally, medullary depression occurs, which refers to the depression of the medulla oblongata in the brainstem, leading to further respiratory depression and potential cardiac arrest.

The given answer, "Increases anxiety," is not a reason for using adjuncts for anesthetics. Adjuncts are used to prevent undesirable effects, reduce the amount of anesthetic needed, and increase the effectiveness of the anesthetic. However, increasing anxiety is not a desired outcome when using adjuncts for anesthetics.

Stress and anxiety do not require a decrease in anesthetic dosing to produce anesthetic effects. In fact, high levels of stress and anxiety can actually increase the amount of anesthetic required for effective anesthesia. This is because stress and anxiety can cause an increase in the body's natural stress response, which can lead to increased heart rate, blood pressure, and metabolism. These physiological changes can result in a faster metabolism of the anesthetic drugs, requiring higher doses to achieve the desired effect.

The mechanism for stage 2 of anesthesia involves higher centers in the brain increasing the release of excitatory neurotransmitters. This leads to a state of amnesia and irregular respiration. The other options mentioned do not accurately describe the mechanism for stage 2 anesthesia.

The correct answer is "Low margin of safety, therefore one of the most dangerous class of drugs." This means that inhalation anesthetics have a narrow range between the therapeutic dose and the toxic dose, making them more dangerous to use compared to other drugs. This narrow margin of safety increases the risk of adverse effects and complications during anesthesia.

The P3 plane or substage of anesthesia refers to the stage where there is a loss of muscle tone. This means that the patient's muscles become relaxed and may even become completely limp. This is an important stage of anesthesia as it allows for easier manipulation of the patient's body during surgical procedures. It is also a sign that the anesthesia is taking effect and the patient is entering a deeper state of unconsciousness.

The P1 plane or substage of anesthesia is characterized by sleep. This means that the patient is in a state of unconsciousness and unawareness of their surroundings. They may appear to be in a deep sleep and have no memory of what occurs during this stage.

Xenon is a noble gas that is used as an anesthetic due to its minimal side effects and ideal properties. It is extremely insoluble in blood, making it safe to use. However, unlike other noble gases, xenon is not relatively inexpensive. It is actually quite expensive, which is why it is not commonly used as an anesthetic. Therefore, the correct answer is "Relatively inexpensive."

Anesthesia is a medical process that involves the administration of drugs to induce analgesia (relief from pain), loss of consciousness, and amnesia (loss of memory). These effects are reversible, meaning that the patient can regain consciousness and normal bodily functions after the drugs wear off. However, the statement "Irreversible" is incorrect because anesthesia is not a permanent state and its effects can be reversed. Additionally, anesthesia is known to decrease autonomic responses rather than increasing them, making the statement "Increased autonomic responses" also incorrect.

The mechanism for stage 4 (medullary depression) of anesthesia is described as neurons in the medulla being normally insensitive, except at high concentrations. This means that under normal circumstances, the neurons in the medulla are not affected by anesthesia, but at high concentrations, they become sensitive to the effects of anesthesia, leading to medullary depression. This can result in respiratory depression, loss of consciousness, and potentially even death if not carefully monitored.

The stages of general anesthesia are typically described as induction (initiation of anesthesia), maintenance (sustaining anesthesia during surgery), and emergence (reversal of anesthesia). Exacerbation refers to a worsening or increase in the severity of a disease or condition, and it is not a recognized stage of general anesthesia.

Ketamine and etomidate are useful for patients at risk for hypotension because they have minimal effects on blood pressure. These anesthetics do not cause significant decreases in blood pressure, making them suitable options for patients who are prone to hypotension.

Sevoflurane is the correct answer because it is a volatile inhalation anesthetic that has been shown to increase respiration. It is commonly used in anesthesia due to its rapid onset and offset of action, as well as its minimal metabolism in the body. Sevoflurane is known to have a respiratory stimulant effect, leading to an increase in tidal volume and respiratory rate. This effect is beneficial during surgery to maintain adequate oxygenation and ventilation.

The fact that hyperbaric condition reverses anesthesia supports the membrane lipid theory used to describe the mechanism of action of general anesthetics. According to this theory, anesthetics affect the lipid bilayer of cell membranes, altering their fluidity and disrupting the normal function of ion channels and receptors. Hyperbaric conditions, which involve increased pressure, can counteract the effects of anesthetics by compressing the cell membranes and reducing the solubility of anesthetics in lipid membranes. This suggests that the lipid bilayer is involved in the mechanism of action of anesthetics.

Ketamine is a dissociative anesthetic that is known for its hallucinogenic effects, including producing hallucinations, illusions, and vivid dreams. Therefore, the statement "Produces hallucinations, illusions, and vivid dreams, especially in children" is incorrect as it contradicts the characteristic of ketamine.

Anesthetics do not enhance memory; instead, they can cause temporary memory loss. They also do not enhance excitatory pathways, such as GABA or glycine, but rather depress synaptic functions. Additionally, anesthetics do not activate the reticular activating system (RAS), which is responsible for arousal and wakefulness.

Isoflurane, enflurane, and desflurane are all inhalation anesthetics that are primarily used for the maintenance of anesthesia. These drugs are administered through inhalation and are commonly used during surgical procedures to maintain the patient in a state of unconsciousness and analgesia. They work by depressing the central nervous system and producing a reversible loss of consciousness. Sevoflurane is also an inhalation anesthetic, but it is commonly used for both induction and maintenance of anesthesia. Thiopental, on the other hand, is an intravenous anesthetic that is typically used for induction of anesthesia rather than maintenance.

Major adjuncts to anesthetics are additional medications or substances used in conjunction with anesthetics to enhance their effects or manage specific aspects of anesthesia. In this case, the correct answer includes nitrous oxide, diazepam, succinylcholine, and fentanyl. These substances are commonly used in anesthesia practice to provide analgesia, muscle relaxation, sedation, and overall anesthesia support during surgical procedures.