Postoperative Delirium — MCQs
Which of the following statements is NOT true about delirium?
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?
Postoperative Delirium Indian Medical PG Practice Questions and MCQs
Question 1: Which of the following statements is NOT true about delirium?
- A. Preserved attention (Correct Answer)
- B. Disorientation
- C. Hallucination
- D. Disturbed sleep
Explanation: ***Preserved attention*** - A core diagnostic feature of **delirium** is a disturbance of attention, meaning attention is **impaired**, not preserved. - Patients typically struggle to focus, sustain, or shift attention. *Disturbed sleep* - Delirium often involves a **disturbance of the sleep-wake cycle**, leading to insomnia during the night and drowsiness during the day. - This disorganized sleep pattern is a common symptom and can contribute to agitation or lethargy. *Disorientation* - Patients with delirium frequently exhibit **disorientation**, particularly to time, place, or person. - This reflects the global cognitive impairment characteristic of the condition. *Hallucination* - **Hallucinations**, particularly visual ones, are commonly experienced by individuals with delirium. - These perceptual disturbances contribute to the agitated or fearful presentation of some delirious patients.
Question 2: 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 3: 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 4: 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 5: 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 6: 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 7: 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 8: 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 9: 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 10: 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.
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