Postoperative Delirium — MCQs
What is the drug of choice for treating delirium tremens?
Emergence delirium is associated with –
What is the most common postoperative psychiatric complication?
True about delirium is all Except:
Which of the following is the LEAST significant risk factor for postoperative pulmonary complications?
Which of the following is the FIRST-LINE antiemetic drug most commonly used for post-operative nausea and vomiting (PONV) prophylaxis?
Which Benzodiazepine decreases post-operative nausea & vomiting:-
In the immediate post operative period the common cause of respiratory insufficiency could be because of the following, except -
What oxygen concentration should be supplemented in all post-operative patients?
A 35-year-old patient is given excessive intravenous Benzodiazepine. She suddenly becomes agitated, combative, and exhibits involuntary movements. The anesthesiologist determines that she is having a reaction to the drug which has been given in excess. What is the next step in management?
Postoperative Delirium Indian Medical PG Practice Questions and MCQs
Question 1: What is the drug of choice for treating delirium tremens?
- A. Phenytoin
- B. Morphine
- C. Lorazepam (Correct Answer)
- D. Diazepam
Explanation: ***Lorazepam*** - **Benzodiazepines** are the first-line treatment for **delirium tremens** due to their effectiveness in reducing central nervous system hyperexcitability through GABA-A receptor agonism. - **Lorazepam** is often preferred, especially in patients with liver impairment (common in chronic alcoholics), because it is metabolized by **glucuronidation** rather than hepatic oxidation, making it safer in hepatic dysfunction. - It has an **intermediate half-life (10-20 hours)** with **no active metabolites**, providing predictable pharmacokinetics and easier dose titration. - Can be administered via multiple routes (IV, IM, oral), making it versatile in acute settings. *Diazepam* - Also a **first-line benzodiazepine** for alcohol withdrawal and delirium tremens, particularly effective in patients with normal liver function. - Has a **long half-life (20-100 hours)** with **active metabolites** (desmethyldiazepam), which can accumulate in patients with hepatic impairment, leading to prolonged sedation. - Metabolized by hepatic **oxidation** (CYP450), making it less ideal in liver disease. - The longer duration of action can be advantageous for tapering protocols but may cause excessive sedation in vulnerable patients. *Phenytoin* - **Phenytoin** is an **anticonvulsant** that is **not effective** for treating delirium tremens or alcohol withdrawal seizures as monotherapy. - It does not address the primary pathophysiology of alcohol withdrawal, which involves GABAergic and glutamatergic system imbalance. - May be used as **adjunctive therapy** in patients with concurrent seizure disorders, but benzodiazepines remain the mainstay. *Morphine* - **Morphine** is an **opioid analgesic** with **no role** in the treatment of delirium tremens. - Use of opioids could **worsen respiratory depression**, particularly dangerous in agitated patients with potential for aspiration. - Does not address the neurochemical basis of alcohol withdrawal and may complicate management.
Question 2: 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 3: What is the most common postoperative psychiatric complication?
- A. Delirium (Correct Answer)
- B. Depression
- C. Psychosis
- D. Anxiety
Explanation: ***Delirium*** - **Delirium** is the most frequent postoperative psychiatric complication, especially in elderly patients and those undergoing major surgery. - It is an acute **neuropsychiatric syndrome** characterized by fluctuating attention, disorganized thinking, and altered level of consciousness. - Incidence ranges from **15-50% in elderly surgical patients** and **up to 80% in ICU settings**. *Depression* - Postoperative depression is common but typically emerges days to weeks after surgery, unlike the acute onset of **delirium**. - While it can significantly affect recovery, its incidence directly after surgery is lower than that of **delirium**. *Psychosis* - Postoperative psychosis is relatively rare and often linked to pre-existing psychiatric conditions, substance withdrawal, or severe medical complications. - It involves more severe thought disturbances and hallucinations than the more common **delirium**. *Anxiety* - Postoperative anxiety is common and can affect recovery, but it is typically **less severe** than delirium. - Unlike delirium, anxiety does not involve altered consciousness or acute cognitive impairment requiring immediate psychiatric intervention.
Question 4: True about delirium is all Except:
- A. Preserved attention (Correct Answer)
- B. Hallucination
- C. Disturbed sleep
- D. Disorientation
Explanation: ***Preserved attention*** - A key feature of **delirium** is a **disturbance in attention**, making it difficult to focus, sustain, or shift attention. - Therefore, **preserved attention** is inconsistent with a diagnosis of delirium. *Hallucination* - **Hallucinations**, particularly visual, are common in delirium and often contribute to the patient's distress and altered perception of reality. - They tend to be vivid, fleeting, and can be frightening. *Disturbed sleep* - **Sleep-wake cycle disturbances** are a hallmark of delirium, often manifesting as insomnia, daytime sleepiness, or a disrupted, fragmented sleep pattern. - This disturbance is part of the global alteration in brain activity. *Disorientation* - **Disorientation**, especially to time, place, and sometimes person, is a frequent symptom of delirium, reflecting the patient's impaired cognitive function. - It indicates a significant impairment in awareness of one's surroundings.
Question 5: Which of the following is the LEAST significant risk factor for postoperative pulmonary complications?
- A. Age > 60 years (Correct Answer)
- B. ASA class 3 and 4 patients
- C. Longer surgeries >2 hr
- D. Upper Abdominal surgery
Explanation: ***Age > 60 years*** - While age is a factor, it is generally considered **less significant** than other comorbid conditions or surgical factors in predicting postoperative pulmonary complications. - Pulmonary function naturally declines with age, but healthy elderly individuals may still tolerate surgery well if other risk factors are controlled. *ASA class 3 and 4 patients* - Patients classified as **ASA (American Society of Anesthesiologists) 3 or 4** have severe systemic disease or life-threatening systemic disease, respectively. - This significantly increases their risk of **postoperative pulmonary complications** due to their underlying health issues. *Longer surgeries >2 hr* - **Prolonged duration of surgery** (typically defined as >2-3 hours) is a significant independent risk factor for pulmonary complications. - This is due to longer periods of **immobility**, ventilation, and exposure to anesthetics, contributing to atelectasis and pneumonia risk. *Upper Abdominal surgery* - **Upper abdominal surgery** is one of the highest risk categories for postoperative pulmonary complications. - Incisions in this area can cause *diaphragmatic dysfunction*, pain leading to shallow breathing, and impaired cough reflex.
Question 6: 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 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: In the immediate post operative period the common cause of respiratory insufficiency could be because of the following, except -
- A. Mild Hypovolemia (Correct Answer)
- B. Residual effect of muscle relaxant
- C. Overdose of narcotic analgesic
- D. Myocardial infarction
Explanation: ***Mild Hypovolemia*** - While significant **hypovolemia** can lead to systemic complications, *mild hypovolemia* itself does not directly cause *respiratory insufficiency* in the immediate postoperative period without other complicating factors. - Hypovolemia primarily affects **cardiovascular stability** and tissue perfusion, not directly the mechanics or drive of respiration unless it progresses to **shock**. *Residual effect of muscle relaxant* - **Residual neuromuscular blockade** can lead to *diaphragmatic weakness* and impaired accessory muscle function, causing insufficient ventilation and respiratory distress. - This is a common cause of *postoperative respiratory insufficiency*, especially if reversal agents are inadequate or not administered. *Overdose of narcotic analgesic* - **Narcotic overdose** depresses the *respiratory drive* in the brainstem, leading to decreased respiratory rate and depth, which can result in **hypoventilation** and *respiratory insufficiency*. - This is a significant concern in the immediate postoperative period due to pain management requirements. *Myocardial infarction* - A *myocardial infarction* can lead to **cardiogenic pulmonary edema** due to impaired cardiac function, resulting in fluid accumulation in the lungs and *respiratory insufficiency*. - Postoperative myocardial infarction is a serious complication that directly impacts respiratory function through its effect on **pulmonary hemodynamics**.
Question 9: What oxygen concentration should be supplemented in all post-operative patients?
- A. 50-60%
- B. 40-45%
- C. 30-35% (Correct Answer)
- D. 20-25%
Explanation: **Explanation:** In the immediate postoperative period, patients are at high risk for **postoperative hypoxemia** due to several factors: residual effects of anesthetic agents (causing respiratory depression), splinting due to pain, and ventilation-perfusion (V/Q) mismatch caused by atelectasis. **Why 30-35% is the Correct Answer:** Standard practice in the Post-Anesthesia Care Unit (PACU) is to provide supplemental oxygen to maintain an arterial oxygen saturation ($SaO_2$) above 94%. An inspired oxygen concentration ($FiO_2$) of **30-35%** is generally sufficient to prevent hypoxemia in most healthy patients without causing complications. This is typically achieved using a simple face mask (5-6 L/min) or nasal prongs (2-4 L/min). **Analysis of Incorrect Options:** * **A & B (40-60%):** These concentrations are unnecessarily high for routine cases. High $FiO_2$ levels can lead to **absorption atelectasis** (where high oxygen replaces nitrogen in the alveoli, causing them to collapse) and can mask hypoventilation by maintaining saturation despite rising $CO_2$ levels. * **D (20-25%):** Room air is 21%. Providing only 20-25% oxygen offers little to no margin of safety against the physiological shunts and decreased Functional Residual Capacity (FRC) common after surgery. **High-Yield Clinical Pearls for NEET-PG:** * **Diffusion Hypoxia:** Specifically seen after Nitrous Oxide ($N_2O$) use; $N_2O$ rushes out of the blood into the alveoli, diluting oxygen. This is prevented by giving **100% $O_2$ for 5-10 minutes** at the end of surgery. * **Target Saturation:** In patients with COPD or chronic hypercapnia, the target $SaO_2$ is lower (88-92%) to avoid suppressing the hypoxic respiratory drive. * **Most common cause of early post-op hypoxemia:** Atelectasis and decreased FRC.
Question 10: A 35-year-old patient is given excessive intravenous Benzodiazepine. She suddenly becomes agitated, combative, and exhibits involuntary movements. The anesthesiologist determines that she is having a reaction to the drug which has been given in excess. What is the next step in management?
- A. Protamine
- B. Flumazenil (Correct Answer)
- C. Buprenorphine
- D. Morphine
Explanation: ### Explanation **Correct Answer: B. Flumazenil** **Mechanism and Rationale:** The patient is experiencing a **paradoxical reaction** to benzodiazepines (BZDs). While BZDs are typically used for sedation and anxiolysis, excessive doses or specific patient factors can trigger agitation, combativeness, and involuntary movements. **Flumazenil** is a specific **competitive antagonist** at the benzodiazepine receptor site on the GABA-A receptor complex. It rapidly reverses both the sedative effects and the paradoxical reactions caused by BZDs. In clinical practice, it is the "gold standard" antidote for BZD overdose or to reverse deep sedation postoperatively. **Analysis of Incorrect Options:** * **A. Protamine:** This is the specific antagonist used to reverse the anticoagulant effects of **Heparin**. It has no role in managing sedative toxicity. * **C. Buprenorphine:** A partial opioid agonist-antagonist used primarily for pain management or opioid de-addiction. It would not reverse BZD-induced symptoms. * **D. Morphine:** An opioid agonist. Giving morphine to an already agitated or over-sedated patient could worsen respiratory depression and complicate the clinical picture. **High-Yield Clinical Pearls for NEET-PG:** * **Half-life Caution:** Flumazenil has a shorter half-life (approx. 1 hour) than most benzodiazepines (e.g., Diazepam). **Resedation** can occur, so the patient must be monitored closely for several hours. * **Contraindication:** Avoid Flumazenil in patients with a history of **seizures** or those on long-term BZDs, as it can precipitate acute withdrawal seizures. * **Dosage:** The initial recommended dose is 0.2 mg IV over 15 seconds, repeated as necessary up to 1 mg. * **Paradoxical Reactions:** These are more common in pediatric and geriatric populations, or those with psychiatric comorbidities.
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