Emergence and Recovery from Anesthesia — MCQs

10 questions

Shivering observed in the early part of the postoperative period is due to

A 40–year female has to undergo incisional hernia surgery under general anaesthesia. She complains of awareness during her past cesarean section. Which of the following monitoring techniques can be used to prevent such awareness ?

Emergence Delirium is characteristic of?

Patient was in an accident and put on mechanical ventilation. He is opening his eyes on verbal command and follows motor commands with all four limbs. What is his GCS score?

Which of the following is the FIRST-LINE antiemetic drug most commonly used for post-operative nausea and vomiting (PONV) prophylaxis?

What is the MOST COMMON cause of apnea after anesthesia?

Which Benzodiazepine decreases post-operative nausea & vomiting:-

Emergence delirium is associated with –

At the end of anaesthesia after discontinuation of nitrous oxide and removal of endotracheal tube, 100% oxygen is administered to the patient to prevent:

Q10

Why 100% oxygen has to be given to a patient after recovering from N2O anesthesia?

Emergence and Recovery from Anesthesia Indian Medical PG Practice Questions and MCQs

Question 1: Shivering observed in the early part of the postoperative period is due to

A. Hypothermia (Correct Answer)
B. Pain
C. Emergence delirium
D. Drug withdrawal

Explanation: **Hypothermia** - Shivering is a primary physiological response to **hypothermia**, an attempt by the body to generate **heat** by increasing muscle activity. - Patients often experience a drop in core body temperature during surgery due to factors like cold operating rooms, exposed body cavities, and anesthetic effects. *Pain* - While pain can cause discomfort and muscle tension, it typically does not manifest as generalized **shivering** in the early postoperative period. - Pain is usually managed with analgesics, and shivering is more indicative of a **thermoregulatory disturbance**. *Emergence delirium* - Emergence delirium is characterized by disorientation, agitation, and non-purposeful movements, but not primarily by **shivering**. - This condition is often related to the residual effects of anesthetic agents or anxiety upon waking. *Drug withdrawal* - Drug withdrawal can cause tremors and agitation, but it is less likely to present as **shivering** in the immediate postoperative period in a patient without a known history of substance dependence. - Withdrawal symptoms typically manifest hours to days after the cessation of the drug, depending on its half-life.

Question 2: A 40–year female has to undergo incisional hernia surgery under general anaesthesia. She complains of awareness during her past cesarean section. Which of the following monitoring techniques can be used to prevent such awareness ?

A. Color doppler
B. Transesophageal echocardiography
C. Bispectral index monitoring (Correct Answer)
D. Pulse plethysmography

Explanation: ***Bispectral index monitoring*** - **Bispectral Index (BIS) monitoring** is a technology that processes electroencephalogram (EEG) signals to provide a numerical value (0-100) indicating the patient's **level of consciousness or depth of anesthesia**. - A lower BIS value (typically 40-60) indicates a suitable depth of anesthesia for surgery, helping to prevent **intraoperative awareness**, especially in patients with a history of it. *Color doppler* - **Color Doppler** is an imaging technique used to visualize blood flow in vessels and assess the speed and direction of flow. - It is primarily used to diagnose conditions like **deep venous thrombosis**, *arterial stenosis*, or to evaluate blood flow to organs, and has no direct role in monitoring depth of anesthesia. *Transesophageal echocardiography* - **Transesophageal echocardiography (TEE)** is an invasive imaging technique that uses ultrasound from a probe inserted into the esophagus to provide detailed images of the heart. - TEE is critical for assessing **cardiac function**, *valvular heart disease*, or *aortic dissection* during surgery, but it does not monitor brain activity or the depth of anesthesia. *Pulse plethysmography* - **Pulse plethysmography** is a non-invasive method that measures changes in blood volume in a part of the body, often used to determine **heart rate** and assess peripheral perfusion. - While it is a component of pulse oximetry, it does not provide information about the **depth of anesthesia** or brain activity.

Question 3: Emergence Delirium is characteristic of?

A. Midazolam
B. Thiopentone
C. Opioids
D. Ketamine (Correct Answer)

Explanation: ***Ketamine*** - **Emergence delirium**, characterized by vivid dreams, hallucinations, and confusion upon recovery from anesthesia, is a known side effect of **ketamine**, particularly in adults. - This effect is attributed to ketamine's action on **NMDA receptors** and can be attenuated by co-administration of benzodiazepines. *Midazolam* - **Midazolam** is a benzodiazepine often used for sedation and anxiolysis, and it typically causes amnesia and relaxation rather than a delirious state upon emergence. - While it can cause paradoxical agitation in some patients, it does not characteristically lead to emergence delirium similar to ketamine. *Thiopentone* - **Thiopentone** is a short-acting barbiturate used for induction of anesthesia, known for rapid onset and offset, leading to smooth emergence without significant delirium. - Its primary effect is general central nervous system depression, not dissociative anesthesia associated with emergence phenomena. *Opioids* - **Opioids** are potent analgesics that, at higher doses, can cause respiratory depression, nausea, and somnolence; however, they do not characteristically cause emergence delirium. - While they can contribute to postoperative cognitive dysfunction, it is distinct from the dissociative emergence state seen with ketamine.

Question 4: Patient was in an accident and put on mechanical ventilation. He is opening his eyes on verbal command and follows motor commands with all four limbs. What is his GCS score?

A. 12
B. 11
C. 9
D. 10 (Correct Answer)

Explanation: ***10*** - **Eye-opening on verbal command scores 3 points** on the GCS (E3). - **Following motor commands with all four limbs scores 6 points** on the GCS (M6). - The patient is on **mechanical ventilation, meaning verbal response is untestable** and scores **1 point (V1T)** for intubated patients. - **Total GCS score: E3 + V1T + M6 = 10T** *12* - This score would incorrectly assume a verbal response of 5 (oriented), which is impossible for an intubated patient. - Would require: E3 + V5 + M4 or similar incorrect combinations that don't match the clinical presentation. *11* - This score would result from incorrect component assignment. - For example, E3 + V2 + M6 = 11, but verbal response cannot be 2 in an intubated patient (must be 1T). - Does not align with the untestable verbal response due to mechanical ventilation. *9* - This score underestimates the patient's neurological status. - Would require: E2 + V1 + M6 = 9, which contradicts the finding that the patient opens eyes on verbal command (E3, not E2). - Incorrectly assigns lower eye-opening score than the clinical presentation indicates.

Question 5: Which of the following is the FIRST-LINE antiemetic drug most commonly used for post-operative nausea and vomiting (PONV) prophylaxis?

A. Lorazepam
B. Metoclopramide
C. Promethazine
D. Ondansetron (Correct Answer)

Explanation: ***Ondansetron*** - **Ondansetron** is a **5-HT3 receptor antagonist** and is considered a first-line agent due to its high efficacy and favorable side effect profile in preventing PONV. - It works by blocking serotonin receptors in the **chemoreceptor trigger zone** and the **gastrointestinal tract**, reducing the sensation of nausea and vomiting. *Lorazepam* - **Lorazepam** is a **benzodiazepine** primarily used for its **anxiolytic** and **sedative effects**, and sometimes as an adjunct for refractory nausea, but not as a first-line antiemetic for PONV prophylaxis. - While it can help indirectly by reducing anxiety, it does not directly target the key pathways involved in PONV as effectively as 5-HT3 antagonists. *Phenytoin* - **Phenytoin** is an **anticonvulsant** medication used to prevent seizures and has no role in the direct treatment or prophylaxis of PONV. - It primarily acts on voltage-gated sodium channels in neurons and does not possess antiemetic properties. *Metoclopramide* - **Metoclopramide** is a **dopamine D2 receptor antagonist** and a **prokinetic agent** that can be used for PONV, particularly when gastric stasis is a concern. - However, it is generally considered a second-line agent due to the risk of **extrapyramidal side effects**, especially with higher doses or prolonged use. *Promethazine* - **Promethazine** is a **first-generation antihistamine** with **antidopaminergic** and **anticholinergic properties** that can be effective for nausea and vomiting. - It is often used as a rescue antiemetic or in combination therapy, but its sedative effects and potential for extrapyramidal symptoms make it less preferable as a first-line prophylactic agent compared to ondansetron.

Question 6: What is the MOST COMMON cause of apnea after anesthesia?

A. Prolonged anesthesia
B. Recurrent intubation leading to airway trauma
C. Neuromuscular blockade (Correct Answer)
D. None of the options

Explanation: ***Neuromuscular blockade*** - **Residual neuromuscular blockade** is a common and often preventable cause of **postoperative apnea** and hypoventilation, as it impairs the patient's ability to maintain an open airway and breathe adequately. - It results from insufficient reversal of **neuromuscular blocking agents (NMBAs)** used during surgery, leading to **weakness of respiratory muscles**. *Prolonged anesthesia* - While prolonged anesthesia can contribute to slower recovery and increased risk of respiratory depression, it is not the *most common* direct cause of **postoperative apnea** compared to residual NMBAs. - The effects of most **anesthetic agents** are usually reversible by the time the patient is extubated, although some residual effects might persist. *Recurrent intubation leading to airway trauma* - **Airway trauma** from recurrent intubation is a serious complication, but it primarily leads to issues like airway edema, bleeding, or vocal cord dysfunction, not typically **apnea**. - While airway issues can compromise breathing, apnea is more directly linked to problems with the **respiratory drive** or **muscle function**. *None of the options* - This option is incorrect because **residual neuromuscular blockade** is a well-established and frequent cause of **postoperative apnea**.

Question 7: Which Benzodiazepine decreases post-operative nausea & vomiting:-

A. Midazolam (Correct Answer)
B. Diazepam
C. Lorazepam
D. All of the options

Explanation: ***Midazolam*** - **Midazolam** is a commonly used benzodiazepine in anesthesia that has been shown to have **antiemetic properties** and can decrease the incidence of **postoperative nausea and vomiting (PONV)**. - Its mechanism may involve its sedative and anxiolytic effects, indirectly reducing the triggers for nausea. *Diazepam* - While **diazepam** is a benzodiazepine with sedative and anxiolytic effects, it is not primarily known for reducing PONV. - Its longer duration of action compared to midazolam can also contribute to unwanted **postoperative sedation**. *Lorazepam* - **Lorazepam** is another benzodiazepine used for anxiolysis and sedation but is not a primary agent for the prevention of PONV. - Like diazepam, its prolonged effects can lead to **delayed recovery** and drowsiness, which may not be desirable in the postoperative period. *All of the options* - While all listed drugs are benzodiazepines, only **midazolam** is consistently recognized and utilized for its ability to reduce PONV in the perioperative setting. - The other benzodiazepines do not demonstrate the same consistent benefit in PONV reduction and may have other side effects that limit their utility for this specific purpose.

Question 8: Emergence delirium is associated with –

A. Halothane
B. Pentothal sodium
C. Droperidol
D. Ketamine (Correct Answer)

Explanation: ***Ketamine*** - **Ketamine**, an N-methyl-D-aspartate (NMDA) receptor antagonist, is known to cause **emergent delirium** or **psychotic reactions** during recovery from anesthesia due to its dissociative properties. - This adverse effect is more common in adults and can manifest as **hallucinations**, **vivid dreams**, and **confusion**, particularly when used as a sole anesthetic agent. *Halothane* - **Halothane** is an inhalational anesthetic that was associated with relatively slow emergence, but not typically with **delirium** as a prominent feature. - Its primary concern was **hepatotoxicity** (halothane hepatitis) and **malignant hyperthermia**, rather than emergence delirium. *Pentothal sodium* - **Pentothal sodium** (thiopental) is a short-acting barbiturate used for induction of anesthesia, known for rapid onset and offset. - While it can cause some **post-operative drowsiness**, it is not primarily associated with **emergent delirium**; instead, it provides a smooth and calm recovery. *Droperidol* - **Droperidol** is an antipsychotic and antiemetic agent often used to prevent post-operative nausea and vomiting, and can cause **sedation**. - It is known to **reduce** the incidence of emergence delirium caused by other agents, rather than causing it itself.

Question 9: At the end of anaesthesia after discontinuation of nitrous oxide and removal of endotracheal tube, 100% oxygen is administered to the patient to prevent:

A. Second gas effect
B. Bronchospasm
C. Hyperoxia
D. Diffusion Hypoxia (Correct Answer)

Explanation: ***Diffusion Hypoxia*** - Post-anaesthesia administration of 100% oxygen prevents **diffusion hypoxia**, a phenomenon where **nitrous oxide** rapidly diffuses out of the blood into the alveoli, diluting alveolar oxygen and carbon dioxide. - This rapid outflow of nitrous oxide can lead to a significant drop in **partial pressure of oxygen** in the alveoli, causing hypoxemia if not counteracted with high inspired oxygen. *Second gas effect* - The **second gas effect** refers to the phenomenon where the rapid uptake of a highly soluble anesthetic (like nitrous oxide) accelerates the uptake of a co-administered less soluble anesthetic. - This is an effect related to the **induction phase** of anesthesia, not emergence, and is distinct from the issues arising from nitrous oxide washout. *Bronchospasm* - **Bronchospasm** is an acute constriction of the bronchioles, often triggered by irritants, allergens, or certain medications. - While it can occur during emergence from anesthesia, it is not directly prevented by administering 100% oxygen and is typically managed with bronchodilators. *Hyperoxia* - **Hyperoxia** is a condition of excess oxygen in the body, which can be detrimental, but it is not the primary concern immediately following the discontinuation of nitrous oxide. - Administering 100% oxygen in this context is a **controlled, short-term measure** to prevent a more immediate and severe issue (hypoxia) rather than causing chronic hyperoxia.

Question 10: Why 100% oxygen has to be given to a patient after recovering from N2O anesthesia?

A. Second gas effect
B. Diffusion hypoxia (Correct Answer)
C. Bronchoconstriction
D. Atelectasis

Explanation: ***Diffusion hypoxia*** - Upon discontinuation of N2O, its rapid diffusion out of the blood into the **alveoli** can dilute the partial pressures of **oxygen** and **carbon dioxide**, leading to hypoxemia and hypercapnia. - Administering 100% oxygen prevents this, ensuring adequate oxygenation while N2O is exhaled. *Second gas effect* - This phenomenon refers to the rapid uptake of a highly soluble anesthetic (like N2O) from the alveoli, which then concentrates the inspired partial pressure of a co-administered less soluble anesthetic, speeding its induction. - This effect is significant during the **induction phase** of anesthesia, not recovery. *Bronchoconstriction* - This is the narrowing of the airways, which can be caused by various factors like allergies, asthma, or irritants, but is not a direct consequence of recovering from N2O anesthesia or a reason for 100% oxygen administration. - While patients with **reactive airway disease** might experience bronchoconstriction under anesthesia, it is not specifically linked to N2O recovery for the general population. *Atelectasis* - This is the collapse of lung tissue, which can occur during or after surgery due to conditions like hypoventilation, airway obstruction, or pressure on the lungs. - Administering 100% oxygen is not used primarily to prevent atelectasis immediately after N2O cessation, although good ventilation and lung recruitment maneuvers are important in preventing it generally.

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