Anesthetic Equipment and Monitoring — MCQs

Anesthetic Equipment and Monitoring Indian Medical PG Practice Questions and MCQs

Question 371: True about anesthesia machine – a) Cylinder is a part of high pressure system b) O2 flush delivers < 35 lit c) O2 flush delivers > 35 lit d) Pipeline is a part of low pressure system

A. bc
B. a
C. ad
D. ac (Correct Answer)

Explanation: ***ac*** - **Cylinder** is indeed a component of the **high-pressure system** of an anesthesia machine, holding gases under high pressure before regulation. - The **O2 flush valve** bypasses the flowmeters and vaporizers, delivering a high flow of oxygen, typically **35-75 L/min**, to the common gas outlet. *bc* - This option is incorrect because while the O2 flush delivers a high flow, stating it delivers **< 35 L/min** is inaccurate; it typically delivers significantly more. - The implication that both b and c are correct cannot be true as they are contradictory (O2 flush cannot deliver both < 35 L/min and > 35 L/min simultaneously). *a* - This option is partially correct as the **cylinder** is part of the high-pressure system, but it omits the correct information about the O2 flush. - It does not account for the accurate statement regarding the flow rate of the O2 flush. *ad* - While the **cylinder** is correctly identified as part of the high-pressure system, the statement that the **pipeline** is part of the **low-pressure system** is incorrect; pipelines are part of the high-pressure system. - The low-pressure system begins after the flowmeters, encompassing components like the vaporizers and the common gas outlet.

Question 372: Modern monitors to measure ETCO2 make use of

A. Laser technology
B. Scatter technology
C. Infrared absorption spectroscopy (Correct Answer)
D. Ultra violet rays

Explanation: ***Infrared absorption spectroscopy*** - This technique relies on the principle that carbon dioxide molecules **absorb infrared light** at specific wavelengths. - A sensor measures the **amount of infrared light absorbed** by the exhaled gases, which is directly proportional to the CO2 concentration. *Laser technology* - While lasers are used in some advanced medical diagnostics, they are **not the primary technology** employed for routine ETCO2 monitoring. - Laser-based techniques for gas analysis are often more complex and **less commonly integrated** into portable or standard capnographs. *Scatter technology* - **Light scattering** methods are typically used to measure particle size or concentration in solutions or aerosols, not gas concentrations. - This technology is **not suitable for detecting specific gas molecules** like CO2 in a breath sample. *Ultra violet rays* - Carbon dioxide molecules **do not significantly absorb ultraviolet (UV) light** in a way that allows for reliable quantitative measurement in medical settings. - UV spectroscopy is used for detecting different types of molecules, but **infrared absorption is specific to CO2** for capnography.

Question 373: A sevoflurane vaporizer can accurately deliver the dose of an anesthetic agent. This accuracy depends on which of the following properties of the anesthetic agent?

A. Vapor pressure (Correct Answer)
B. Blood gas partition coefficient
C. Molecular weight
D. Oil gas partition coefficient

Explanation: ***Vapor pressure*** - Sevoflurane vaporizers are designed to deliver a specific concentration of anesthetic gas by controlling the amount of carrier gas (**oxygen** or **air**) that flows over or through a liquid anesthetic. - The precise control relies on the **vapor pressure** of the liquid anesthetic, which determines how much vapor is formed at a given temperature. *Blood gas partition coefficient* - The **blood gas partition coefficient** describes the solubility of an anesthetic in blood relative to inspired gas, influencing the **speed of onset** and **recovery**. - It does not directly affect the vaporizer's ability to accurately deliver a set concentration of anesthetic from the liquid state. *Molecular weight* - **Molecular weight** is important for the physical properties of the anesthetic, but it does not directly determine the accuracy of vapor delivery by the vaporizer. - While it plays a role in diffusion, the vaporizer's function is primarily driven by vapor pressure and flow dynamics. *Oil gas partition coefficient* - The **oil gas partition coefficient** indicates the solubility of an anesthetic in fat, reflecting its **potency** and distribution into fatty tissues. - This coefficient influences the **pharmacodynamics** and tissue distribution of the anesthetic but has no direct bearing on the accuracy of the vaporizer's output of a specific vapor concentration.

Question 374: Inhalational anesthetic with highest respiratory irritation is:-

A. Desflurane (Correct Answer)
B. Halothane
C. Nitrous oxide
D. Sevoflurane

Explanation: ***Desflurane*** - **Desflurane** has the highest **pungency** among common inhalational anesthetics, leading to significant respiratory irritation. - This irritation can manifest as **coughing**, **laryngospasm**, and **bronchospasm**, particularly during induction. *Halothane* - **Halothane** is a less pungent anesthetic and is generally well-tolerated by the respiratory system. - It was historically known for its **bronchodilating properties**, making it less irritating than Desflurane. *Nitrous oxide* - **Nitrous oxide** is a gaseous anesthetic with a very low solubility and virtually no respiratory irritant properties. - It is often used as a carrier gas and is known for its quick onset and offset without causing airway reactivity. *Sevoflurane* - **Sevoflurane** is known for its sweet smell and is considered a non-pungent agent, making it suitable for inhalational induction, especially in children. - It causes minimal respiratory irritation and has **bronchodilating effects**, which are beneficial in patients with reactive airway disease.

Question 375: Depth of Anesthesia is best measured by:

A. TOF
B. MAC
C. BIS (Correct Answer)
D. Post Tetanic Potentiation

Explanation: ***BIS*** - The **BIS (Bispectral Index)** is an EEG-derived parameter that provides a quantitative measure of the patient's level of consciousness or depth of anesthesia. - A typical range for adequate surgical anesthesia is a BIS score between **40 and 60**, indicating a low probability of consciousness and recall. *TOF* - **TOF (Train-of-Four)** monitoring is used to assess the level of neuromuscular blockade, measuring the response of a muscle to a series of four electrical stimuli. - While important for managing **muscle relaxants**, it does not directly measure the depth of anesthesia or consciousness. *MAC* - **MAC (Minimum Alveolar Concentration)** is a measure of the potency of an inhaled anesthetic, defined as the concentration at which 50% of patients do not respond to a surgical stimulus. - It reflects the **ED50 of the anesthetic agent** itself rather than the patient's individual depth of anesthesia at a given moment. *Post Tetanic Potentiation* - **Post Tetanic Potentiation (PTP)** is a phenomenon observed during neuromuscular monitoring where a single twitch response is enhanced following a brief tetanus (rapid series of high-frequency stimuli). - PTP is used to assess **deep neuromuscular blockade** and recovery from paralytics, not the depth of anesthesia.

Question 376: Neuromuscular monitoring shows TOF ratio 0.7. This indicates:

A. Adequate recovery
B. Complete recovery
C. Partial recovery (Correct Answer)
D. Deep block

Explanation: ***Partial recovery*** - A **TOF ratio of 0.7** indicates significant recovery from neuromuscular blockade, but not full return to baseline. - This level might allow for some spontaneous movements but could still pose a risk for **post-operative respiratory complications** due to residual weakness. *Adequate recovery* - Adequate recovery is generally considered when the **TOF ratio is 0.9 or greater**, indicating near-normal muscle function and reduced risk of residual block complications. - At a TOF ratio of 0.7, although significant recovery has occurred, the patient is still susceptible to **airway obstruction** and **hypoventilation**. *Complete recovery* - **Complete recovery** from neuromuscular blockade is defined by a TOF ratio of **1.0**, meaning the fourth twitch is equal in amplitude to the first, indicating no residual paralysis. - A TOF ratio of 0.7 does not signify complete recovery as there is still a noticeable fade in subsequent twitches. *Deep block* - A **deep block** would be characterized by a very low TOF ratio or the absence of all four twitches in the train-of-four stimulus. - A TOF ratio of 0.7 clearly shows the presence of all four twitches, negating the possibility of a deep block.

Question 377: Which of the following is a second-generation laryngeal mask airway (LMA)?

A. Ambu
B. Classic LMA
C. LMA Flexible
D. LMA Proseal (Correct Answer)

Explanation: ***LMA Proseal*** - The **LMA Proseal** is classified as a second-generation LMA because it incorporates features like a **gastric access channel** (drain tube) to allow for suctioning of gastric contents and a **higher seal pressure** around the glottis. - These advancements improve **airway protection** and ventilation efficacy compared to first-generation devices. *Ambu* - The term "Ambu" primarily refers to the company that manufactures various medical devices, including LMAs, but does not specify a particular LMA model that is exclusively second-generation. - Ambu has produced both first and second-generation supraglottic airway devices. *Classic LMA* - The **Classic LMA** is considered a **first-generation** laryngeal mask airway. - It lacks features such as a gastric access channel and typically provides a lower seal pressure, offering less protection against aspiration. *LMA Flexible* - The **LMA Flexible** is also a **first-generation** laryngeal mask airway, distinguished by its wire-reinforced, flexible tube allowing for surgical access to the head and neck. - While it has a specialized design, it does not possess the inherent safety features (e.g., gastric access) that define second-generation devices.

Question 378: In a patient undergoing surgery with significant blood loss, which parameter is monitored using TEG or ROTEM?

A. Clot Elasticity (Correct Answer)
B. Fibrinogen Level
C. Thrombin Time
D. Platelet Function

Explanation: ***Clot Elasticity*** - Both **Thromboelastography (TEG)** and **Rotational Thromboelastometry (ROTEM)** directly assess the mechanical strength and elasticity of the developing clot, which is crucial in managing significant blood loss. - This parameter, often represented by the maximum amplitude (MA) on TEG or maximum clot firmness (MCF) on ROTEM, reflects the overall contribution of platelets and fibrinogen to clot strength. *Platelet Function* - While TEG and ROTEM provide insights into **platelet contribution** to clot strength, they do not specifically isolate individual platelet functions like aggregation or adhesion. - Dedicated platelet function tests (e.g., light transmission aggregometry) would be needed for a detailed assessment of specific **platelet defects**. *Fibrinogen Level* - TEG and ROTEM can infer the contribution of **fibrinogen** to clot strength, particularly through parameters like the alpha angle and MA/MCF. - However, they do not directly measure the **quantitative fibrinogen level**; this requires specific laboratory assays such as the Clauss method. *Thrombin Time* - **Thrombin time** is a separate coagulation test that measures the time it takes for a clot to form after adding thrombin to plasma, primarily assessing **fibrinogen conversion to fibrin**. - This parameter is not directly measured by TEG or ROTEM, although the initial phase of clot formation (R-time on TEG, CT on ROTEM) can be influenced by thrombin generation.

Question 379: During a surgical procedure, a 70-year-old male develops hypotension and bradycardia after the administration of a muscle relaxant. What is the most likely cause?

A. Atracurium
B. Vecuronium
C. Succinylcholine (Correct Answer)
D. Rocuronium

Explanation: ***Succinylcholine*** - **Succinylcholine** can cause **bradycardia** and **hypotension** due to its direct stimulation of **muscarinic receptors** at the SA node, especially with repeat doses or in susceptible individuals. - This effect is more pronounced in **children** and in adults receiving a second dose within a short period, leading to a **parasympathomimetic response**. *Vecuronium* - **Vecuronium** is an **intermediate-acting non-depolarizing neuromuscular blocker** that is generally associated with minimal cardiovascular effects. - It does not typically cause **bradycardia** or **hypotension** at clinical doses, as it lacks significant **histamine release** or **ganglionic blockade**. *Atracurium* - **Atracurium** is an **intermediate-acting non-depolarizing neuromuscular blocker** that can cause **histamine release**, leading to **hypotension** and **tachycardia** (not bradycardia). - The observed **bradycardia** in the patient makes atracurium an unlikely cause, as its cardiovascular effects are primarily related to vasodilation from **histamine**. *Rocuronium* - **Rocuronium** is a **rapid-onset, intermediate-acting non-depolarizing neuromuscular blocker** that has minimal cardiovascular effects. - It is known for its stability and does not typically induce **bradycardia** or **hypotension**, making it a less likely cause for the patient’s symptoms.

Question 380: What is the significance of monitoring central venous pressure (CVP) during major surgery?

A. To assess fluid status and guide fluid therapy (Correct Answer)
B. To monitor for cardiac ischemia
C. To evaluate respiratory function
D. To detect electrolyte imbalances

Explanation: ***To assess fluid status and guide fluid therapy*** - **CVP** reflects the pressure in the **right atrium** and **vena cava**, serving as an indicator of **right ventricular preload** and overall **circulating blood volume**. - Monitoring CVP helps clinicians determine if a patient is **hypovolemic** (low CVP), **hypervolemic** (high CVP), or euvolemic, guiding the appropriate administration of **intravenous fluids** or diuretics. *To monitor for cardiac ischemia* - While cardiac function is critical during surgery, CVP is not a direct or primary monitor for **cardiac ischemia**. - **Electrocardiography (ECG)**, **troponin levels**, and **echocardiography** are more direct methods for detecting myocardial ischemia. *To evaluate respiratory function* - CVP primarily reflects intravascular volume and cardiac filling pressures, not **respiratory function**. - **Respiratory function** is assessed through measures like **tidal volume**, **respiratory rate**, **oxygen saturation**, and **end-tidal CO2**. *To detect electrolyte imbalances* - CVP measurement directly assesses pressure, not the concentration of specific substances in the blood. - **Electrolyte imbalances** are detected through **blood tests** that measure levels of **sodium**, **potassium**, **calcium**, etc.

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

Want unlimited practice?

Get full access to all questions, explanations, and performance tracking.

Start For Free