Anesthetic Equipment and Monitoring Practice Questions

Q: Early and reliable indication of air embolism during anaesthesia can be obtained by continuous monitoring of:

End Tidal CO2. ***End Tidal CO2*** - A sudden and unexplained decrease in **End Tidal CO2 (EtCO2)** is often the first sign of an air embolism. - This occurs because air in the pulmonary circulation obstructs blood flow, leading to reduced CO2 delivery to the lungs. *Oxygen saturation* - **Oxygen saturation** changes are typically a later sign of air embolism, as significant pulmonary impairment or right-to-left shunting must occur before a drop is detectable. - A decrease in saturation indicates a more advanced and potentially severe embolism. *ECG* - **ECG changes**, such as arrhythmias or signs of right heart strain, are usually late and non-specific indicators of air embolism. - These changes reflect the cardiovascular consequences of the embolism rather than its initial event. *Blood pressure* - A drop in **blood pressure** is a late and often profound sign of an air embolism, reflecting significant cardiovascular compromise. - Early detection methods precede observable changes in systemic blood pressure.

Q: Hardening of sodalime done by?

Sodium silicate. **Sodium silicate** - **Sodium silicate** solution, also known as **water glass**, is used to harden soda lime. - It reacts with **calcium hydroxide** in the soda lime to form a durable, insoluble matrix, increasing its structural integrity. *BaSO4* - **Barium sulfate (BaSO4)** is an insoluble salt primarily used as a **radiocontrast agent** in medical imaging. - It does not possess properties that would facilitate the hardening of soda lime. *CaCO3* - **Calcium carbonate (CaCO3)** is a common filler or antacid and is a primary component of chalk and limestone. - It does not react with soda lime in a way that would induce hardening; in fact, soda lime is often used to absorb CO2. *CaSO4* - **Calcium sulfate (CaSO4)**, particularly in its hydrated forms (like plaster of Paris), is known for its hardening properties. - However, for hardening soda lime, the interaction with calcium hydroxide specifically favors **sodium silicate** due to the formation of a rigid silicate structure.

Q: Curare notch seen in capnograph is due to

Spontaneous breathing. ***Spontaneous breathing*** - The "Curare notch" a dip in the expiratory plateau of the **capnograph waveform**, occurs when a patient begins to initiate **spontaneous breaths** against the ventilator. - This signifies that the **neuromuscular blockade** from paralytic agents (like curare derivatives) is wearing off. *Carbon dioxide rebreathing* - **CO2 rebreathing** would typically elevate the baseline of the capnogram and potentially prolong the expiratory plateau, but it would not create a characteristic notch. - This is usually caused by insufficient fresh gas flow or a faulty absorbent, leading to the patient inhaling previously exhaled CO2. *Valve malfunction* - A **valve malfunction**, such as a stuck expiratory valve, would typically cause a persistent elevation of the expiratory CO2 plateau or an inability to exhale, rather than a transient notch. - This would indicate a problem with the mechanical ventilation circuit. *Bronchospasm* - **Bronchospasm** typically results in a **sloping or shark fin-shaped expiratory plateau** on the capnogram due to prolonged expiration and uneven gas emptying from the lungs. - It does not produce a distinct "notch" as seen with the return of spontaneous breathing.

Q: All are the Complication of CVP line except

Airway injury. ***Airway injury*** - While central venous catheterization can cause various complications, direct **airway injury** (e.g., tracheal puncture) is extremely rare and not a typical complication of the procedure itself as the insertion sites are generally not near the major airways. - Complications usually involve vascular, pleural, or infectious issues rather than direct damage to the respiratory tree. *Haemothorax* - **Haemothorax** can occur if the subclavian or internal jugular vein is punctured and the needle or catheter inadvertently punctures an adjacent artery (e.g., subclavian artery), leading to bleeding into the pleural space. - This complication presents with respiratory distress and signs of hypovolemia as blood accumulates in the thoracic cavity. *Air embolism* - **Air embolism** is a serious complication, especially during insertion or removal of a CVP line, if the catheter lumen is exposed to air and negative intrathoracic pressure sucks air into the venous system. - It can lead to sudden cardiorespiratory collapse and is a recognized risk of CVP placement. *Septicemia* - **Septicemia** (or central line-associated bloodstream infection, CLABSI) is a common and serious complication, particularly with prolonged catheter dwelling times, poor aseptic technique, or inadequate site care. - Bacteria can colonize the catheter surface and enter the bloodstream, leading to systemic infection.

Q: Colour of oxygen cylinder is –

Black with white shoulder. ***Black with white shoulder*** - Medical oxygen cylinders are typically **black** with a **white shoulder** to allow for clear identification. - This standardized color coding helps healthcare professionals quickly distinguish oxygen from other medical gases. *Grey* - Grey cylinders are commonly used for **carbon dioxide** in medical settings. - Using a grey cylinder for oxygen would be a **safety hazard** due to incorrect gas delivery. *Blue* - Blue cylinders are typically designated for **nitrous oxide** (laughing gas). - Administering nitrous oxide instead of oxygen could lead to **hypoxia and adverse patient outcomes**. *White* - White cylinders are often used to identify **compressed air** in medical facilities. - Confusion with compressed air could lead to a lack of oxygen delivery to a patient in need, which is **life-threatening**.

Q: Heparin interferes with which of the following results of ABG

All of the options. ***Correct: All of the options*** Heparin interferes with **all three major parameters** of arterial blood gas (ABG) analysis when used in excess amounts: **pH - Acidic effect:** - Heparin is an acidic solution (pH approximately 5-7) - Excess heparin in the sample causes **falsely low pH** readings - The acidic nature of heparin directly lowers the pH of the blood sample **PO2 - Dilutional and metabolic effects:** - Heparin dilutes the blood sample, affecting oxygen concentration - Can cause **falsely decreased PO2** if excess liquid heparin is used [1] - Cellular metabolism in delayed samples can consume oxygen, further reducing PO2 - Effect is more pronounced if analysis is not performed promptly **PCO2 - Dilutional effect:** - Excess heparin causes **dilution** of the blood sample - Results in **falsely decreased PCO2** readings [1] - The dilutional effect is the primary mechanism affecting PCO2 measurement **Clinical Pearl:** To minimize interference, use the minimum amount of heparin necessary (just enough to coat the syringe), avoid liquid heparin when possible, and analyze samples promptly after collection.

Q: The function of the Heidbrink meter in Boyle's machine is to:

Indicates flow of gases. ***Indicates flow of gases*** - The **Heidbrink meter** is a type of **rotameter** designed to visibly indicate the **flow rate** of gases to the patient. - Its tapered tube and rotating bobbin allow the anesthesiologist to accurately monitor the **volume of gas** delivered. *Reduces pressure of gases* - **Pressure regulators** and **reducing valves** are responsible for reducing gas pressure from cylinders or pipelines, not the Heidbrink meter. - Flowmeters operate after pressure has been reduced to a safe and usable level. *It is a fixed orifice meter* - A Heidbrink meter is a **variable orifice flowmeter**, where the annular space around the bobbin changes with flow. - **Fixed orifice meters** rely on a constant opening and measure pressure differential across it to determine flow. *Indicates humidity of gases* - Devices like **hygrometers** or **humidifiers** are used to measure or add moisture to gases, respectively. - The Heidbrink meter's sole function is to display **gas flow**, not humidity.

Q: What are the present-day applications of oxygen concentrators?

All of the options. ***All of the options*** - Oxygen concentrators are versatile devices used in various medical settings due to their ability to provide a continuous supply of concentrated oxygen without the need for large, heavy oxygen tanks. - Their convenience, portability, and cost-effectiveness make them suitable for multiple applications, from home use to critical care transport and even as a source gas for anesthesia. *Domiciliary use* - Oxygen concentrators are widely used in **home care** settings for patients with chronic respiratory conditions like **COPD** or **pulmonary fibrosis**, who require long-term oxygen therapy. - They provide a continuous, on-demand supply of oxygen, reducing the need for frequent refills of oxygen cylinders. *Supplying ambulances* - Portable oxygen concentrators are increasingly used in **emergency medical services (EMS)** and during **patient transport** in ambulances. - They offer a lightweight and efficient oxygen source, crucial for immediate respiratory support during transit. *Supplying anesthesia machines* - Oxygen concentrators can be used to supply oxygen to **anesthesia machines**, especially in areas where piped medical gas systems are unavailable or unreliable. - They act as a **primary or backup source of oxygen** for mixing with anesthetic agents for patient ventilation during surgery.

Q: True about Rotameter:

The height to which bobbin rises indicates the flow rate. ***The height to which bobbin rises indicates the flow rate*** - A rotameter is a **variable-area flowmeter** where the height reached by the bobbin directly correlates with the **flow rate** of the gas. - As gas flow increases, the **drag force** on the bobbin increases, causing it to rise higher in the tapered tube until the drag force equals the bobbin's weight. *Rotameter reading may not get affected by density inside the tube* - The **fluid density** significantly affects the rotameter reading, as the buoyant force and drag force depend on it. - Variations in **gas composition** or **pressure**, which change density, will alter the bobbin's position for a given flow rate. *Rotameter reading may not get affected by static electricity* - **Static electricity** can cause the bobbin in a rotameter to stick to the sides of the glass tube, leading to inaccurate readings. - This is particularly problematic with **dry gases** flowing through glass tubes. *A rotameter is a variable pressure flowmeter* - A rotameter is a **variable-area flowmeter**, meaning the cross-sectional area through which the fluid flows changes. - **Variable pressure flowmeters** (e.g., orifice plates) involve a constant flow area but a variable pressure drop.

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

ac. ***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 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 1

Early and reliable indication of air embolism during anaesthesia can be obtained by continuous monitoring of:

Accepted Answer

End Tidal CO2

Answer

Oxygen saturation

Answer

ECG

Answer

Blood pressure

Question 2

Hardening of sodalime done by?

Accepted Answer

Sodium silicate

Answer

BaSO4

Answer

CaCO3

Answer

CaSO4

Question 3

Curare notch seen in capnograph is due to

Accepted Answer

Spontaneous breathing

Answer

Carbon dioxide rebreathing

Answer

Valve malfunction

Answer

Bronchospasm

Question 4

All are the Complication of CVP line except

Accepted Answer

Airway injury

Answer

Haemothorax

Answer

Air embolism

Answer

Septicemia

Question 5

Colour of oxygen cylinder is –

Accepted Answer

Black with white shoulder

Answer

Grey

Answer

Blue

Answer

White

Question 6

Heparin interferes with which of the following results of ABG

Accepted Answer

All of the options

Answer

pH

Answer

PO2

Answer

PCO2

Question 7

The function of the Heidbrink meter in Boyle's machine is to:

Accepted Answer

Indicates flow of gases

Answer

Reduces pressure of gases

Answer

It is a fixed orifice meter

Answer

Indicates humidity of gases

Question 8

What are the present-day applications of oxygen concentrators?

Accepted Answer

All of the options

Answer

Domiciliary use

Answer

Supplying ambulances

Answer

Supplying anesthesia machines

Question 9

True about Rotameter:

Accepted Answer

The height to which bobbin rises indicates the flow rate

Answer

Rotameter reading may not get affected by density inside the tube

Answer

Rotameter reading may not get affected by static electricity

Answer

A rotameter is a variable pressure flowmeter

Question 10

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

Accepted Answer

ac

Answer

bc

Answer

a

Answer

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Anesthetic Equipment and Monitoring — MCQs

Anesthetic Equipment and Monitoring — MCQs

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