Anesthetic Equipment and Monitoring — MCQs
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What is the composition of soda lime?
What is the ionized calcium (IC) content of Ringer's lactate in mmol/L, and why is it clinically significant?
Which of the following is a characteristic of the Supreme Laryngeal Mask Airway (LMA)?
What is the PRIMARY application of capnography during patient monitoring?
Critical temperature of oxygen is?
Circuit of choice for controlled ventilation ?
Which inhalational anesthetic has the highest global warming potential?
Which anaesthetic drug contributes to green house effect?
Central venous monitoring is typically used for all of the following except:
Phase II block is seen with:
Anesthetic Equipment and Monitoring Indian Medical PG Practice Questions and MCQs
Question 401: What is the composition of soda lime?
- A. 4% NaOH, 90% Ca(OH)2, 1% KOH, 5% H2O
- B. 15% NaOH, 80% Ca(OH)2, trace elements, 4% H2O
- C. 4% NaOH, 80% Ca(OH)2, 1% KOH, 15% H2O
- D. 4% NaOH, 80% Ca(OH)2, trace elements, 15% H2O (Correct Answer)
Explanation: ***4% NaOH, 80% Ca(OH)2, trace elements, 15% H2O*** - **Soda lime** is primarily composed of **calcium hydroxide (Ca(OH)2)**, typically around 80%, which acts as the main absorbent. - It also contains **sodium hydroxide (NaOH)**, around 4%, which serves as an activator, along with approximately 15% **water (H2O)** to facilitate the reaction, and **trace elements** like potassium hydroxide. *4% NaOH, 90% Ca(OH)2, 1% KOH, 5% H2O* - This option shows a higher percentage of **calcium hydroxide (90%)** and a lower percentage of **water (5%)** than the standard composition. - The reduced water content might impair the efficiency of **carbon dioxide absorption**. *4% NaOH, 80% Ca(OH)2, 1% KOH, 15% H2O* - While the percentages of NaOH, Ca(OH)2, and H2O are closer to correct, this option specifically mentions **potassium hydroxide (KOH)** as a distinct component at 1%, rather than general trace elements. - The standard composition usually encompasses trace elements more broadly, and specific percentages for KOH are not always highlighted as a primary component. *15% NaOH, 80% Ca(OH)2, trace elements, 4% H2O* - This composition incorrectly suggests a significantly higher percentage of **sodium hydroxide (15%)** and a critically low percentage of **water (4%)**. - A higher NaOH concentration can increase the risk of **carbon monoxide formation** from halogenated anesthetics, and inadequate water reduces absorptive capacity.
Question 402: What is the ionized calcium (IC) content of Ringer's lactate in mmol/L, and why is it clinically significant?
- A. 4 mmol/L (Correct Answer)
- B. 0 mmol/L
- C. 130 mmol/L
- D. 109 mmol/L
Explanation: ***4 mmol/L*** - Ringer's lactate contains **calcium chloride**, contributing to its ionized calcium content of **4 mmol/L**. - This calcium is a critical component for **blood clotting** and **cardiac function**, making it clinically significant, particularly in large volume resuscitation. *130 mmol/L* - This value is close to the **sodium content** of Ringer's lactate, not its ionized calcium. - Sodium is the primary determinant of **fluid balance** and **osmolarity**, distinct from calcium's roles. *109 mmol/L* - This value approximates the **chloride content** of Ringer's lactate, which is important for acid-base balance but not its ionized calcium. - Chloride's primary role is in maintaining **electrical neutrality** and fluid distribution. *0 mmol/L* - Ringer's lactate is a **balanced electrolyte solution** and definitely contains calcium. - A value of 0 would indicate the absence of calcium, which would contradict its formulation and clinical utility, especially in scenarios requiring **electrolyte repletion**.
Question 403: Which of the following is a characteristic of the Supreme Laryngeal Mask Airway (LMA)?
- A. Designed specifically for infants
- B. Utilizes high pressure, low volume cuff design
- C. Includes a built-in drain tube (Correct Answer)
- D. Does not have a bite block
Explanation: ***Includes a built-in drain tube*** - The **Supreme Laryngeal Mask Airway (LMA)** features an integrated **drain tube** to facilitate gastric decompression and reduce the risk of aspiration. - This design allows for the passage of a gastric tube, which can be useful during longer procedures or in patients with a higher risk of gastric content regurgitation. *Designed specifically for infants* - While LMAs are available in various sizes for all age groups, the **Supreme LMA** is not designed *specifically* for infants; it is a general-purpose LMA available in multiple sizes for different patient populations. - Other LMA types, such as the LMA Unique, are more commonly associated with a broader pediatric application. *Utilizes high pressure, low volume cuff design* - The **Supreme LMA** actually utilizes a **low pressure, high volume cuff** design, which helps contour to the perilaryngeal anatomy and minimizes pressure on mucosal tissues. - A high pressure, low volume cuff is associated with traditional endotracheal tubes and could lead to increased tissue ischemia if used with an LMA. *Does not have a bite block* - The **Supreme LMA** incorporates an **integrated bite block** within its design to prevent occlusion of the airway tube from patient biting. - This feature helps maintain airway patency and protects the LMA from damage, making it a key characteristic.
Question 404: What is the PRIMARY application of capnography during patient monitoring?
- A. Correct intubation (Correct Answer)
- B. Pulmonary embolism
- C. Adequate ventilation
- D. Significant metabolic change
Explanation: ***Correct intubation*** - Capnography is the **gold standard** for confirming **endotracheal tube (ETT) placement** by detecting carbon dioxide in exhaled breath. - A persistent waveform indicates the ETT is in the **trachea**, while absence suggests esophageal intubation. *Pulmonary embolism* - While capnography can show a **decrease in end-tidal CO2 (ETCO2)** due to increased dead space in pulmonary embolism, it is not its primary or most definitive diagnostic application. - Other diagnostic methods like CT pulmonary angiogram are preferred for confirming pulmonary embolism. *Adequate ventilation* - Capnography provides information about **ETCO2 levels**, which can indirectly reflect adequate ventilation by showing CO2 elimination. - However, it's more direct application is intubation confirmation, and other measures like **tidal volume** and **respiratory rate** are also crucial for assessing overall ventilation. *Significant metabolic change* - Capnography can show changes in CO2 production reflecting metabolic rate, such as in **hypermetabolic states** (e.g., fever, sepsis) or hypometabolic states. - While useful for monitoring trends, its primary role is not for diagnosing such changes but rather intubation confirmation.
Question 405: Critical temperature of oxygen is?
- A. -118°C (Correct Answer)
- B. 400°C
- C. 20°C
- D. 36.5°C
Explanation: ***-118°C*** - The **critical temperature** is the temperature above which a gas cannot be liquefied, no matter how much pressure is applied. - For oxygen, its critical temperature is approximately **-118°C**, meaning it can only exist as a gas above this temperature, regardless of pressure. *400°C* - This temperature is significantly **above** the critical temperature of oxygen, so oxygen would always be a gas at this temperature. - It does not represent any specific physical property of oxygen in relation to its phase changes. *20°C* - This temperature is also well **above** oxygen's critical temperature, so oxygen would remain in its gaseous state. - This is approximately room temperature, where oxygen is commonly found as a gas. *36.5°C* - This is close to typical human body temperature and is far **above** the critical temperature of oxygen. - At this temperature, oxygen exists only as a gas.
Question 406: Circuit of choice for controlled ventilation ?
- A. Magill circuit
- B. Type C
- C. Type E
- D. Type D (Correct Answer)
Explanation: **Type D** - The **Type D circuit** (also known as the **Bain circuit** or a modified Mapleson D circuit) is highly efficient for **controlled ventilation** due to its fresh gas flow entering near the patient, effectively sweeping away exhaled gases. - Its design maintains a relatively constant **expiratory resistance**, making it suitable for precise control of ventilation parameters. *Magill circuit* - The **Magill circuit** (Mapleson A) is efficient for **spontaneous ventilation** but requires a high fresh gas flow to prevent rebreathing during controlled ventilation. - During controlled ventilation, a high minute volume is required to flush out expired gases efficiently, which can be wasteful of anesthetic agents. *Type C* - The **Type C circuit** (Mapleson C circuit) is a simple system useful for **resuscitation** and short procedures but is inefficient for prolonged controlled ventilation. - It has a high resistance to gas flow and a tendency for significant rebreathing during both spontaneous and controlled breathing, leading to high CO2 levels. *Type E* - The **Type E circuit** (Mapleson E circuit) is a basic T-piece system, primarily used for **spontaneous breathing in infants and children**. - It lacks a reservoir bag and adjustable pressure limiting valve, making it unsuitable for controlling ventilation effectively in adults.
Question 407: Which inhalational anesthetic has the highest global warming potential?
- A. Desflurane (Correct Answer)
- B. Isoflurane
- C. Sevoflurane
- D. Halothane
Explanation: ***Desflurane*** - **Desflurane** has the highest global warming potential among commonly used volatile anesthetics due to its high **infrared absorbance** and long **atmospheric lifetime**. - Its environmental impact is a recognized concern, leading to efforts to reduce its use in clinical practice. *Isoflurane* - **Isoflurane** has a lower global warming potential and atmospheric lifetime compared to **desflurane**. - While it contributes to greenhouse gas emissions, its impact is less significant than desflurane. *Sevoflurane* - **Sevoflurane** has the lowest global warming potential and the shortest atmospheric lifetime among the modern volatile anesthetics. - It is often considered a more **environmentally friendly** option compared to desflurane and isoflurane. *Halothane* - **Halothane** is an older inhalational anesthetic that is rarely used today due to concerns about **hepatotoxicity** and **cardiac arrhythmias**. - Although it has ozone-depleting potential due to its chlorine content, its global warming potential is less than desflurane and its clinical use is negligible.
Question 408: Which anaesthetic drug contributes to green house effect?
- A. Enflurane
- B. Sevoflurane
- C. Halothane
- D. Desflurane (Correct Answer)
Explanation: **Desflurane** - **Desflurane** has the highest **global warming potential (GWP)** among commonly used volatile anesthetics, primarily due to its long atmospheric half-life and potent infrared absorption. - Its environmental impact is also amplified by its high **minimum alveolar concentration (MAC)** and low blood solubility, requiring higher delivered concentrations for anesthesia. *Enflurane* - **Enflurane** has a lower GWP compared to desflurane and is less commonly used in modern practice. - While it contributes to the greenhouse effect, its impact is significantly less than that of desflurane due to differences in chemical structure and atmospheric persistence. *Sevoflurane* - **Sevoflurane** has a relatively low GWP and a short atmospheric half-life compared to desflurane, making it a more environmentally friendly option among volatile anesthetics. - Although it still contributes to atmospheric warming, its overall environmental impact is considerably less than desflurane's. *Halothane* - **Halothane** is a potent greenhouse gas but is no longer used in many parts of the world due to concerns about hepatotoxicity and its significant ozone-depleting potential. - While it contributes to atmospheric warming, its current lack of clinical use limits its ongoing contribution to the greenhouse effect compared to currently utilized agents.
Question 409: Central venous monitoring is typically used for all of the following except:
- A. Administering thrombolytics (Correct Answer)
- B. Deciding the need for plasma infusion
- C. Deciding the requirement for blood transfusion
- D. Regulating the speed and amount of fluid infusion
Explanation: ***Administering thrombolytics*** - Central venous monitoring is a technique used to measure central venous pressure (CVP), which reflects right atrial pressure and indirectly **right ventricular preload**. It does not directly relate to the administration of **thrombolytics**. - Thrombolytics are typically administered intravenously through a peripheral or central line to dissolve clots, but CVP monitoring is not a prerequisite or a direct function of this administration. *Regulating the speed and amount of fluid infusion* - **Central venous pressure (CVP)** monitoring is crucial for assessing a patient's **fluid status** and guiding fluid resuscitation. - By continuously monitoring CVP, clinicians can determine whether to increase, decrease, or maintain the rate of **fluid infusion** to optimize cardiac preload without causing fluid overload. *Deciding the need for plasma infusion* - CVP values help assess **circulatory volume** and guide decisions on fluid replacement, including the need for **plasma infusion** in conditions like severe hypovolemia or coagulopathy. - A low CVP in a patient with bleeding or coagulation issues might indicate the need for volume expansion with **plasma**. *Deciding the requirement for blood transfusion* - **Low CVP** can indicate **hypovolemia**, which might be due to blood loss, thereby suggesting the need for a **blood transfusion**. - While not the sole determinant, CVP is one of several physiological parameters used to assess the urgency and amount of **blood products** required to restore circulating volume and oxygen-carrying capacity.
Question 410: Phase II block is seen with:
- A. SCh infusion (Correct Answer)
- B. Single dose SCh
- C. Mivacurium
- D. None of the options
Explanation: ***SCh infusion*** - A **prolonged infusion or high dose** of succinylcholine (SCh) can lead to a **Phase II block**, a desensitizing block resembling that of a non-depolarizing neuromuscular blocker. - This occurs due to the **persistent presence of SCh** at the neuromuscular junction, which initially depolarizes the endplate (Phase I) but eventually leads to **receptor desensitization** and repolarization, preventing further muscle contraction. *Single dose SCh* - A **single bolus dose of succinylcholine** typically produces a **Phase I block**, characterized by initial muscle fasciculations followed by flaccid paralysis due to persistent depolarization of the motor endplate. - It resolves relatively quickly as **succinylcholine is rapidly hydrolyzed** by pseudocholinesterase, usually not leading to a prolonged desensitization characteristic of Phase II. *Mivacurium* - **Mivacurium** is an intermediate-acting, **non-depolarizing neuromuscular blocker**. - Its mechanism of action involves **competitively binding to nicotinic acetylcholine receptors** at the neuromuscular junction, thereby preventing acetylcholine from binding and initiating muscle contraction, which is fundamentally different from a Phase II block caused by prolonged depolarization. *None of the options* - This option is incorrect because **SCh infusion** is a recognized cause of Phase II block. - The phenomenon of Phase II block is a well-established pharmacological response to **excessive and prolonged exposure** to depolarizing neuromuscular blockers like succinylcholine.
Practice by Chapter
Anesthesia Machine Components
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Breathing Systems
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Vaporizers
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Gas Cylinders and Pipeline Supply
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Anesthesia Ventilators
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Standard Monitoring: ECG, BP, Pulse Oximetry
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Capnography
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Neuromuscular Monitoring
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Temperature Monitoring
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Invasive Hemodynamic Monitoring
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Equipment Troubleshooting
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Safety Features in Modern Anesthesia Equipment
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