Anesthetic Equipment and Monitoring — MCQs

Anesthetic Equipment and Monitoring Indian Medical PG Practice Questions and MCQs

Question 341: True about anesthesia cylinders is all EXCEPT:

A. Most commonly used cylinder is type E.
B. DISS is the safety mechanism to prevent wrong fitting of cylinder to machine. (Correct Answer)
C. Air is stored in cylinder with grey body with black and white shoulder.
D. Cylinders are part of high pressure system.

Explanation: *DISS is the safety mechanism to prevent wrong fitting of cylinder to machine.* - **DISS (Diameter Index Safety System)** is a safety system used on pipelines and some cylinder connections, but not on the primary connection of a cylinder to an anesthesia machine which uses the **PISS (Pin Index Safety System)**. - The **PISS** is specifically designed to prevent the wrong gas cylinder from being fitted to the wrong yoke on the anesthesia machine. ***Most commonly used cylinder is type E.*** - **Type E cylinders** are indeed the most commonly used size for anesthetic gases attached directly to the anesthesia machine. - Their compact size makes them suitable for use as **reserve gas supplies** on the machine or for transport. *Cylinders are part of high pressure system.* - Gas cylinders contain gases at very high pressures (e.g., oxygen up to **2200 psi**), making them part of the **high-pressure system** of the anesthesia machine. - This high pressure needs to be reduced by a **pressure regulator** before the gas can be delivered to the patient. *Air is stored in cylinder with grey body with black and white shoulder.* - The correct color coding for **medical air cylinders** is a **grey body** with **black and white shoulders**. - This standardized color coding helps healthcare professionals quickly identify the cylinder's contents.

Question 342: Amount of water that constitutes soda lime in carbon dioxide absorber is

A. 25-30%
B. 10-14%
C. 20-24%
D. 14-19% (Correct Answer)

Explanation: ***14-19%*** - **Soda lime** typically contains **14-19% water** by weight, which acts as a crucial catalyst in the chemical reaction with carbon dioxide. - The presence of water is essential for the **hydration of calcium hydroxide** and the formation of **carbonic acid**, facilitating CO2 absorption. *25-30%* - This percentage of water is **too high** for optimal soda lime function, potentially leading to a slushy consistency or **reduced CO2 absorption efficiency**. - Excess water can also increase the risk of **dusting** and airway irritation. *10-14%* - While closer, this range represents slightly **less than optimal water content**, which could lead to **slower CO2 absorption** rates. - Insufficient water might also decrease the overall **absorbent capacity** of the soda lime. *20-24%* - This water content is **higher than the ideal range** and could negatively impact the performance of soda lime by compromising its granular structure. - It might also contribute to **channeling** within the absorber, reducing efficient CO2 removal.

Question 343: Which of the following anaesthetic agent causes bone marrow suppression?

A. Isoflurane
B. Halothane
C. Ketamine
D. Nitrous Oxide (Correct Answer)

Explanation: ***Nitrous Oxide*** - **Nitrous oxide** can cause **bone marrow suppression** due to its ability to irreversibly oxidize the **cobalamin cofactor** of **methionine synthase**. - This inactivation leads to reduced DNA synthesis and impacts rapidly dividing cells like those in the bone marrow, potentially causing **megaloblastic anemia** with prolonged or repeated exposure. *Isoflurane* - **Isoflurane** is a volatile anesthetic known for its minimal effects on bone marrow function. - It primarily acts on the central nervous system to induce anesthesia and muscle relaxation with limited systemic toxicities. *Halothane* - **Halothane** is associated with **hepatotoxicity** (halothane hepatitis) in some susceptible individuals, but not bone marrow suppression. - Its use has largely been replaced by newer, safer volatile anesthetics due to this risk. *Ketamine* - **Ketamine** is a dissociative anesthetic that primarily affects the central nervous system, causing analgesia and amnesia. - It does not significantly impact bone marrow function or hematopoiesis.

Question 344: Sodium content of Ringer's lactate is (mEq/L):

A. 144
B. 130 (Correct Answer)
C. 12
D. 154

Explanation: ***130*** - **Ringer's lactate** solution typically contains 130 mEq/L of **sodium**, making it an **isotonic** solution with an osmolality of approximately 273 mOsm/L. - This concentration makes it an appropriate fluid for **volume resuscitation** as it closely mimics the **extracellular fluid** composition. *144* - This value is higher than the typical **sodium content** of Ringer's lactate and is more commonly associated with the sodium level in **plasma**. - Administering a solution with this higher sodium concentration might lead to **hypernatremia** if not indicated. *12* - This value is extremely low and does not represent the **sodium content** of Ringer's lactate or any commonly used intravenous fluid for **volume replacement**. - A solution with such low sodium would be highly **hypotonic** and could cause dangerous **cellular swelling**. *154* - This **high sodium concentration** is characteristic of **normal saline (0.9% NaCl)**, which contains 154 mEq/L of sodium. - Unlike Ringer's lactate, normal saline also has a **higher chloride content**, which can lead to **hyperchloremic metabolic acidosis** with large volumes.

Question 345: Stage 2 block (Phase II block) is seen with:

A. Isoflurane
B. Enflurane
C. Suxamethonium (Correct Answer)
D. Sevoflurane

Explanation: ***Suxamethonium*** - **Suxamethonium** (succinylcholine) is a depolarizing neuromuscular blocker that can cause a **Phase II block** with prolonged or high-dose administration. - Phase II block, also known as **desensitization block**, clinically resembles a non-depolarizing block and can be antagonized by **anticholinesterases**. *Isoflurane* - **Isoflurane** is an inhaled anesthetic that causes muscle relaxation by enhancing the effects of non-depolarizing neuromuscular blockers, but does not directly induce a Phase II block. - It primarily acts on GABA receptors in the CNS to produce anesthesia and has minimal direct effect on **nicotinic acetylcholine receptors** at the neuromuscular junction. *Enflurane* - **Enflurane** is another inhaled anesthetic that, similar to isoflurane, potentiates neuromuscular blockade but does not directly cause a **Phase II block**. - Its effects are primarily on the **central nervous system**, contributing to anesthesia and muscle relaxation through central mechanisms. *Sevoflurane* - **Sevoflurane** is a commonly used inhaled anesthetic that also enhances the effects of neuromuscular blockers but does not cause a unique **Phase II block** itself. - Like other volatile anesthetics, it facilitates muscle relaxation, thereby reducing the dose of neuromuscular blockers required.

Question 346: What is the pin index of O2-CO2 (CO2 < 7.5%)?

A. 1,6 (Correct Answer)
B. 2,6
C. 3,6
D. 4,6

Explanation: ***1,6*** - The pin index system for medical gases helps ensure the correct gas is connected to the appropriate equipment. For **O2-CO2 mixtures with CO2 less than 7.5%**, the pin index is **1,6**. - This specific pin configuration prevents accidental administration of the wrong gas mixture, ensuring patient safety. *2,6* - This pin index configuration is typically associated with **medical air**, which is a mixture of nitrogen and oxygen, not an O2-CO2 mixture. - Using the wrong pin index could lead to connecting a medical air cylinder to an O2-CO2 port, potentially causing inappropriate gas delivery. *3,6* - This pin index configuration is designated for **nitrous oxide**. - Connecting a nitrous oxide cylinder to an O2-CO2 port would be a severe medical error, as these gases have very different clinical applications and effects. *4,6* - This pin index corresponds to **carbon dioxide (CO2)** when it is supplied as a pure gas or in higher concentrations. - While O2-CO2 mixtures contain CO2, the specific pin index 4,6 is not used for mixtures with CO2 less than 7.5%, distinguishing it for pure CO2 applications.

Question 347: Ideal anaesthetic circuit for spontaneously breathing pediatric patient is:-

A. Bains circuit
B. Magills circuit (Correct Answer)
C. Jackson rees circuit
D. Mapleson D

Explanation: ***Magills circuit*** - This is a **Mapleson A** system, which is the most efficient for spontaneously breathing patients due to its ability to prevent rebreathing and minimize fresh gas flow requirements. - While pediatric patients are often managed with other circuits due to anatomical and physiological considerations, the Magill circuit's design makes it theoretically ideal for spontaneous breathing in any patient. *Bains circuit* - The Bain circuit is a **Mapleson D** system, which is more suited for controlled ventilation rather than spontaneous breathing due to its configuration. - While it offers advantages like warmth and humidification, its efficiency for spontaneous breathing is lower, often requiring higher fresh gas flows to prevent rebreathing. *Jackson rees circuit* - The Jackson Rees modification is a type of **Mapleson F** circuit, which is an adaptation of the Ayre's T-piece. It is commonly used in pediatrics due to its low resistance and suitability for both spontaneous and controlled ventilation. - However, for *spontaneous breathing*, it is less efficient than the Magill circuit in terms of fresh gas flow requirements, as it relies on a high fresh gas flow to flush exhaled gases. *Mapleson D* - The Mapleson D circuit is efficient for **controlled ventilation** due to the position of the fresh gas inlet near the patient and a long expiratory limb with a reservoir bag and APL valve at the machine end. - For spontaneous breathing, it is less efficient than a Mapleson A circuit (like the Magill), as higher fresh gas flows are required to prevent rebreathing of exhaled CO2.

Question 348: An anaesthetic agent with boiling temperature more than 75°C

A. Halothane
B. Methoxyflurane (Correct Answer)
C. Cyclopropane
D. Ether

Explanation: ***Methoxyflurane*** - Methoxyflurane has a **boiling point of 104.7 °C**, making it the only agent listed with a boiling temperature above 75°C. - Its high boiling point and low vapor pressure necessitate the use of specialized **calibrated vaporizers** for safe administration [1]. *Halothane* - Halothane has a **boiling point of 50.2 °C**, which is significantly lower than 75°C [1]. - It was a commonly used inhalational anesthetic but has largely been replaced due to concerns about **hepatotoxicity**. *Cyclopropane* - Cyclopropane is a gas at room temperature and has a very low boiling point of **-32.9 °C**. - It is highly **flammable and explosive**, limiting its modern use in anesthesia. *Ether* - Diethyl ether (commonly known as simply "ether") has a boiling point of **34.6 °C**. - It was one of the earliest general anesthetics but is no longer used due to its **flammability** and slow induction/recovery.

Question 349: Capnography is useful for

A. Determining Vaporizer malfunction or contamination
B. Determining circuit hypoxia
C. Detecting concentration of oxygen in the anesthetic circuit.
D. Determining the appropriate placement of endotracheal (Correct Answer)

Explanation: ***Determining the appropriate placement of endotracheal*** - Capnography provides a direct and continuous measurement of **exhaled CO2**, which confirms proper **endotracheal tube (ETT) placement** in the trachea. - The presence of a square-wave capnogram with a distinct end-tidal CO2 (ETCO2) value indicates CO2 detection, confirming the ETT is in the airway and not the esophagus. *Determining Vaporizer malfunction or contamination* - **Anesthetic gas analyzers**, not capnographs, are used to detect vaporizer malfunctions or contamination by measuring the concentration of specific anesthetic agents. - While a capnograph might show changes in CO2 if ventilation is affected by an issue with the vaporizer, it does not directly diagnose the vaporizer problem itself. *Determining circuit hypoxia* - **Oxygen analyzers** in the anesthetic circuit are used to determine the concentration of oxygen, which helps detect circuit hypoxia. - Capnography monitors CO2 levels, and while changes in CO2 might indirectly result from hypoxia, it doesn't directly measure oxygen concentration or alert to hypoxia. *Detecting concentration of oxygen in the anesthetic circuit.* - **Oxygen sensors or galvanic cells**, integrated into the anesthesia machine, are specifically designed to measure the inspired oxygen concentration. - Capnography measures carbon dioxide, not oxygen, and therefore cannot directly assess the oxygen levels within the anesthetic circuit.

Question 350: Sodalime circuit is not used in anaesthesia with:

A. Trichloroethylene (Correct Answer)
B. Enflurane
C. Methoxyflurane
D. Isoflurane

Explanation: ***Trichloroethylene*** - **Trichloroethylene** reacts with **sodalime** to produce **dichloroacetylene**, which is neurotoxic and can cause cranial nerve palsies due to heat generation. - Due to this hazardous interaction, trichloroethylene is strictly contraindicated for use in a **sodalime circuit**. *Enflurane* - While enflurane can undergo some degradation by sodalime at high temperatures to form **Compound A**, this effect is much less significant compared to trichloroethylene. - The level of Compound A formed with enflurane in a sodalime circuit is generally considered clinically insignificant under normal operating conditions. *Methoxyflurane* - **Methoxyflurane** reacts with sodalime to produce **nephrotoxic compounds** like fluoride and oxalic acid, which can cause high-output renal failure. - Despite this, its reaction with sodalime is different from the neurotoxic products formed with trichloroethylene. *Isoflurane* - **Isoflurane** is comparatively stable in the presence of sodalime and shows minimal degradation. - It does not produce significant toxic byproducts when used in a sodalime circuit, making it a safe choice.

Practice by Chapter

Anesthesia Machine Components

Practice Questions

Breathing Systems

Practice Questions

Vaporizers

Practice Questions

Gas Cylinders and Pipeline Supply

Practice Questions

Anesthesia Ventilators

Practice Questions

Standard Monitoring: ECG, BP, Pulse Oximetry

Practice Questions

Capnography

Practice Questions

Neuromuscular Monitoring

Practice Questions

Temperature Monitoring

Practice Questions

Invasive Hemodynamic Monitoring

Practice Questions

Equipment Troubleshooting

Practice Questions

Safety Features in Modern Anesthesia Equipment

Practice Questions

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