Preoperative Evaluation and Management — MCQs

Preoperative Evaluation and Management Indian Medical PG Practice Questions and MCQs

Question 11: A 27-year-old male patient is referred for resection of pheochromocytoma. Which of the following medications should the patient be taking prior to surgery?

A. Propranolol
B. Labetalol
C. Phenoxybenzamine (Correct Answer)
D. Hydralazine

Explanation: ### Explanation **Phenoxybenzamine** is the correct answer because the primary goal in the preoperative management of pheochromocytoma is to achieve **alpha-blockade before beta-blockade.** #### 1. Why Phenoxybenzamine? Pheochromocytomas secrete excessive catecholamines (norepinephrine and epinephrine), leading to severe hypertension and vasoconstriction. Phenoxybenzamine is an **irreversible, non-competitive alpha-adrenoceptor antagonist**. It is the gold standard for preoperative preparation because it stabilizes blood pressure and allows for intravascular volume expansion (reversing the "contracted" state caused by chronic vasoconstriction). This prevents intraoperative hypertensive crises during tumor manipulation. #### 2. Why the Other Options are Incorrect: * **Propranolol (Option A):** This is a non-selective beta-blocker. If given alone, it blocks $\beta_2$-mediated vasodilation, leaving $\alpha$-mediated vasoconstriction unopposed. This leads to a **paradoxical hypertensive crisis**. Beta-blockers should only be started *after* adequate alpha-blockade is established. * **Labetalol (Option B):** While it has both alpha and beta-blocking properties, the ratio of $\beta:\alpha$ antagonism is approximately 7:1. This predominant beta-blockade can still lead to unopposed alpha-stimulation and hypertensive episodes. * **Hydralazine (Option D):** This is a direct vasodilator. While it can lower blood pressure, it does not address the underlying catecholamine-receptor pathophysiology required for pheochromocytoma stabilization. #### 3. Clinical Pearls for NEET-PG: * **The 10-14 Day Rule:** Alpha-blockade (Phenoxybenzamine) is typically started 10–14 days before surgery. * **Roizen Criteria:** Used to assess the adequacy of preoperative alpha-blockade (e.g., BP <160/90 mmHg, presence of orthostatic hypotension, and absence of ST-T changes on ECG). * **Fluid Resuscitation:** Patients must be encouraged to take a high-salt diet and adequate fluids once alpha-blockade begins to counteract orthostatic hypotension and expand plasma volume.

Question 12: Which statement regarding calcium channel blockers in anesthesia is TRUE?

A. They need to be decreased as they augment hypotension and muscle relaxation.
B. They should be withheld because they lower LES pressure.
C. They should be given in normal doses as they prevent MI and angina. (Correct Answer)
D. All of the above.

Explanation: **Explanation:** The perioperative management of chronic medications is a high-yield topic in Anesthesiology. The correct approach to **Calcium Channel Blockers (CCBs)** is to **continue them in normal doses** throughout the perioperative period, including on the morning of surgery. **1. Why Option C is Correct:** CCBs (such as diltiazem, verapamil, or nifedipine) are primarily used for hypertension, supraventricular arrhythmias, and coronary artery disease. Continuing them ensures hemodynamic stability and maintains the balance between myocardial oxygen supply and demand. Abrupt withdrawal can lead to **rebound hypertension** or **reflex tachycardia**, which significantly increases the risk of perioperative myocardial ischemia and angina. **2. Why Other Options are Incorrect:** * **Option A:** While CCBs can theoretically augment the effects of volatile anesthetics (hypotension) and neuromuscular blocking agents (muscle relaxation) by interfering with calcium ion flux, these effects are clinically manageable. The risk of cardiac instability from withdrawal far outweighs the risk of mild potentiation. * **Option B:** Although CCBs can decrease Lower Esophageal Sphincter (LES) pressure, this is not a contraindication for surgery. Standard aspiration prophylaxis (e.g., fasting, H2 blockers) is sufficient to manage this risk. **High-Yield Clinical Pearls for NEET-PG:** * **"Continue" List:** Beta-blockers, CCBs, Statins, and Digoxin should generally be continued on the day of surgery. * **"Withhold" List:** ACE inhibitors and ARBs are typically withheld 24 hours prior to surgery to prevent **refractory hypotension** during induction. * **Diuretics:** Usually withheld on the morning of surgery to avoid intraoperative hypovolemia and electrolyte imbalances. * **Antiplatelets:** Aspirin is often continued for secondary prevention, while Clopidogrel is stopped 5–7 days prior for high-bleeding-risk surgeries.

Question 13: A 45-year-old male with a history of smoking is scheduled for elective surgery. Which of the following statements regarding the effects of smoking is FALSE?

A. The effect of nicotine on aortic and carotid bodies can increase sympathetic tone.
B. Carbon monoxide shifts the O2-Hb dissociation curve to the right. (Correct Answer)
C. Muscle relaxant dose requirements are increased in smokers.
D. Smoking decreases surfactant levels.

Explanation: **Explanation:** **Why Option B is the correct (False) statement:** Carbon monoxide (CO) has an affinity for hemoglobin that is 200–250 times greater than oxygen, forming carboxyhemoglobin. This results in two major effects: it reduces the oxygen-carrying capacity of the blood and, crucially, it **shifts the oxygen-hemoglobin dissociation curve to the LEFT**. A leftward shift increases the affinity of hemoglobin for the remaining oxygen molecules, making it harder for oxygen to be released to the peripheral tissues, thereby worsening tissue hypoxia. **Analysis of other options:** * **Option A:** Nicotine stimulates the autonomic nervous system by acting on the aortic and carotid bodies, leading to increased sympathetic tone. This results in tachycardia, peripheral vasoconstriction, and hypertension. * **Option C:** Chronic smoking induces hepatic microsomal enzymes (Cytochrome P450). This accelerated metabolism can lead to an increased dose requirement for certain drugs, including some neuromuscular blocking agents (muscle relaxants). * **Option D:** Smoking causes a decrease in pulmonary surfactant production and impairs its function, contributing to small airway collapse and increased work of breathing. **High-Yield Clinical Pearls for NEET-PG:** * **Short-term cessation (12–24 hours):** Reduces carboxyhemoglobin levels (half-life is 4–6 hours) and normalizes heart rate/blood pressure due to nicotine elimination. * **Intermediate cessation (2–4 weeks):** Improvement in airway closure and sputum volume. * **Long-term cessation (6–8 weeks):** Optimal period to reduce postoperative pulmonary complications (PPC); it allows for the recovery of ciliary function and normalization of immune response. * **Paradoxical effect:** Stopping smoking immediately before surgery (<24 hours) may temporarily increase airway secretions and irritability.

Question 14: Atropine when used as a pre-medication causes all of the following symptoms except:

A. Skin flush
B. Bronchoconstriction (Correct Answer)
C. Prevents bradycardia
D. Dryness of mouth

Explanation: **Explanation:** Atropine is a competitive **muscarinic antagonist** (anticholinergic) commonly used in pre-anesthetic medication. Its primary mechanism involves blocking the action of acetylcholine at parasympathetic effector sites. **Why Bronchoconstriction is the Correct Answer:** Atropine causes **bronchodilation**, not bronchoconstriction. By blocking M3 receptors on bronchial smooth muscles, it reduces airway resistance and decreases secretions. This property is particularly beneficial in patients with hyperreactive airways, though it is not the primary drug for asthma. **Analysis of Incorrect Options:** * **Skin Flush:** Atropine causes cutaneous vasodilation (known as "Atropine flush"), especially in the blush area. This occurs due to a compensatory mechanism to dissipate heat, as atropine inhibits sweat glands (thermoregulatory sweating), leading to hyperthermia. * **Prevents Bradycardia:** This is a primary clinical use. Atropine blocks M2 receptors at the SA node, increasing the heart rate. It is used preoperatively to counteract vagal reflexes triggered by surgical manipulation or certain anesthetic agents (e.g., halothane, succinylcholine). * **Dryness of Mouth:** Atropine potentally inhibits salivary secretions (antisialogogue effect) by blocking M3 receptors in salivary glands. This is useful in anesthesia to maintain a clear airway and facilitate intubation. **NEET-PG High-Yield Pearls:** * **Order of Sensitivity:** Salivary, bronchial, and sweat glands are highly sensitive to atropine (inhibited at low doses), while the heart and eyes require moderate doses, and the GI tract/bladder require higher doses. * **Blood-Brain Barrier:** Unlike Glycopyrrolate, Atropine is a tertiary amine and **crosses the BBB**, potentially causing postoperative delirium or "Central Anticholinergic Syndrome" in the elderly. * **Contraindication:** Avoid in patients with **Narrow-Angle Glaucoma** (causes mydriasis and cycloplegia) and Prostatic Hypertrophy (causes urinary retention).

Question 15: Atropine as preanesthesia has all effects except?

A. Decrease secretion
B. Bronchoconstriction (Correct Answer)
C. Prevent bradycardia
D. Prevent hypotension

Explanation: **Explanation:** Atropine is a competitive **muscarinic acetylcholine receptor antagonist** (anticholinergic). Its use in premedication is based on its ability to block parasympathetic (vagal) activity. **Why "Bronchoconstriction" is the correct answer:** Atropine causes **bronchodilation**, not bronchoconstriction. By blocking the M3 receptors on bronchial smooth muscle, it inhibits the constrictive effects of acetylcholine. This increases anatomical dead space but is beneficial in preventing intraoperative bronchospasm. **Analysis of other options:** * **A. Decrease secretion:** Atropine is a potent antisialagogue. It blocks M3 receptors in salivary and bronchial glands, reducing secretions. This is crucial for maintaining a clear airway and preventing laryngospasm during induction. * **C. Prevent bradycardia:** Atropine exerts a positive chronotropic effect by blocking M2 receptors at the SA node, thereby counteracting vagal-induced bradycardia caused by surgical maneuvers (e.g., traction on extraocular muscles) or drugs (e.g., succinylcholine, halothane). * **D. Prevent hypotension:** By preventing or treating bradycardia, atropine helps maintain cardiac output (CO = HR × SV), thereby preventing a drop in blood pressure associated with vagal stimulation. **NEET-PG High-Yield Pearls:** 1. **Blood-Brain Barrier:** Atropine is a tertiary amine; it **crosses** the BBB and can cause Central Anticholinergic Syndrome (confusion/delirium), especially in the elderly. 2. **Order of Potency:** * **Antisialagogue:** Scopolamine > Glycopyrrolate > Atropine. * **Tachycardia:** Atropine > Glycopyrrolate > Scopolamine. 3. **Contraindication:** Relative contraindication in patients with **narrow-angle glaucoma** (causes mydriasis) and prostatic hypertrophy (causes urinary retention). 4. **Glycopyrrolate** is often preferred over Atropine as it is a quaternary ammonium (does not cross BBB) and has a longer duration of action.

Question 16: According to AHA/American College of Cardiology guidelines, which of the following is NOT considered surgery with high risk in patients with known coronary artery disease?

A. Emergency surgery
B. Peripheral vascular surgery
C. Carotid endarterectomy (Correct Answer)
D. Aortic aneurysm surgery

Explanation: The AHA/ACC guidelines categorize surgical procedures based on the estimated risk of major adverse cardiac events (MACE) within 30 days. This classification is crucial for preoperative optimization in patients with coronary artery disease (CAD). ### **Explanation of the Correct Answer** **C. Carotid endarterectomy** is classified as an **Intermediate-risk surgery** (risk of MACE 1–5%). While it involves major vascular structures, it is generally less hemodynamically stressful than aortic or peripheral bypass surgeries. Other intermediate-risk procedures include head and neck surgery, orthopedic surgery, and prostate surgery. ### **Analysis of Incorrect Options (High-Risk Procedures)** High-risk surgeries are those with a reported cardiac risk of **>5%**. * **A. Emergency surgery:** Particularly in the elderly, emergency procedures carry the highest risk due to the inability to optimize the patient’s cardiac status preoperatively. * **B. Peripheral vascular surgery:** Procedures like distal revascularization are high-risk because peripheral artery disease is a strong surrogate for systemic atherosclerosis and silent CAD. * **D. Aortic aneurysm surgery:** Major vascular surgeries involving the aorta involve significant fluid shifts, blood loss, and cross-clamping stress, placing extreme demand on the myocardium. ### **NEET-PG High-Yield Pearls** * **Low-risk procedures (<1%):** Endoscopic procedures, cataract surgery, superficial surgery, and breast surgery. * **Functional Capacity:** Measured in Metabolic Equivalents (METs). If a patient can perform **>4 METs** (e.g., climbing two flights of stairs) without symptoms, they generally do not require further cardiac testing, regardless of the surgery type. * **Revised Cardiac Risk Index (Lee’s Criteria):** A common tool used to predict perioperative cardiac risk based on six predictors (High-risk surgery, Ischemic heart disease, CHF, Cerebrovascular disease, Insulin-dependent Diabetes, and Creatinine >2 mg/dL).

Question 17: A drug belongs to the anticholinergic drug group and is primarily used in preanesthetic medication and also during surgery. Which of the following can be this drug?

A. Glycopyrrolate (Correct Answer)
B. Pipenzolate methyl bromide
C. Isopropamide
D. Dicyclomine

Explanation: ### Explanation **Correct Option: A. Glycopyrrolate** **Why it is correct:** Glycopyrrolate is a synthetic **quaternary ammonium anticholinergic** agent. In anesthesia, it is the preferred drug for premedication and intraoperative use for several reasons: 1. **Antisialagogue effect:** It effectively reduces salivary and tracheobronchial secretions, ensuring a dry airway for intubation. 2. **Vagolytic effect:** It prevents or treats intraoperative bradycardia (e.g., due to the oculocardiac reflex or traction on viscera). 3. **Quaternary structure:** Unlike Atropine or Scopolamine, it does not cross the blood-brain barrier. This avoids central anticholinergic syndrome (confusion/sedation), making it safer for elderly patients. 4. **Reversal of Neuromuscular Blockade:** It is frequently co-administered with Neostigmine to counteract the muscarinic side effects (bradycardia, secretions) of the acetylcholinesterase inhibitor. **Why other options are incorrect:** * **B. Pipenzolate methyl bromide:** This is a synthetic anticholinergic primarily used as an antispasmodic for gastrointestinal disorders (like peptic ulcers), not in anesthesia. * **C. Isopropamide:** This is a long-acting anticholinergic used specifically for its antisecretory and antispasmodic effects in the GI tract. * **D. Dicyclomine:** This is a tertiary amine used primarily for its direct smooth muscle relaxant action in Irritable Bowel Syndrome (IBS) and intestinal colic. **High-Yield Clinical Pearls for NEET-PG:** * **Potency:** Glycopyrrolate is **twice as potent** as Atropine as an antisialagogue but has a slower onset and less initial tachycardia. * **Placental Barrier:** Because it is a quaternary ammonium, it **does not cross the placenta**, making it the drug of choice for preventing bradycardia in obstetric anesthesia. * **Heart Rate:** Atropine is preferred over Glycopyrrolate in emergency situations (like severe sinus bradycardia) because it has a faster onset of action.

Question 18: Polygelin content is found in which of the following fluids?

A. Gelofuscine
B. Haemaccel (Correct Answer)
C. Hartmann's solution
D. Hetastarch

Explanation: **Explanation:** **Haemaccel** is a synthetic colloid used for volume replacement. It is specifically composed of **Polygeline**, which is a polymer of degraded gelatin cross-linked with urea. It has a molecular weight of approximately 30,000 Daltons and is unique because it contains significant concentrations of electrolytes, specifically **Calcium (6.25 mmol/L)** and Potassium. **Analysis of Options:** * **Gelofuscine (Option A):** This is also a gelatin-based colloid, but it consists of **succinylated gelatin** in isotonic saline. Unlike Haemaccel, it does not contain calcium and is not cross-linked with urea. * **Hartmann's Solution (Option B):** This is a crystalloid, also known as **Ringer's Lactate**. It contains sodium chloride, sodium lactate, potassium chloride, and calcium chloride, but no gelatin or polygeline. * **Hetastarch (Option D):** This is a **Hydroxyethyl Starch (HES)**, a synthetic colloid derived from amylopectin. It is a glucose polymer, not a protein/gelatin derivative. **High-Yield Clinical Pearls for NEET-PG:** 1. **Calcium Content:** Because Haemaccel contains calcium, it should **not** be infused through the same line as citrated blood, as it may cause clotting (recalcification of blood). 2. **Anaphylaxis:** Gelatins (Haemaccel and Gelofuscine) have a higher incidence of anaphylactoid reactions compared to starches or crystalloids due to histamine release. 3. **Renal Safety:** Unlike older Hydroxyethyl starches, polygelins have a minimal effect on renal function and coagulation profiles. 4. **Metabolism:** Polygelin is primarily excreted unchanged by the kidneys.

Question 19: Which of the following is used as a preanesthetic medication?

A. Propanthelene
B. Glycopyrrolate (Correct Answer)
C. Ipratropium bromide
D. Hyoscine

Explanation: ### Explanation **Correct Answer: B. Glycopyrrolate** **Concept:** Preanesthetic medications are administered to reduce anxiety, provide sedation, and minimize potential complications of anesthesia. **Antisialagogues** (anticholinergics) are used to decrease salivary and bronchial secretions, preventing laryngospasm and maintaining a clear airway. **Glycopyrrolate** is the preferred choice because it is a **quaternary ammonium compound**. Unlike other anticholinergics, it does not cross the blood-brain barrier (BBB) or the placenta. This ensures effective reduction of secretions without causing central nervous system side effects like sedation, delirium, or postoperative cognitive dysfunction. It also has a longer duration of action and causes less tachycardia compared to Atropine. **Analysis of Incorrect Options:** * **A. Propanthelene:** This is a synthetic quaternary ammonium compound primarily used for its antispasmodic effects in gastrointestinal disorders (like peptic ulcers) rather than as a routine preanesthetic medication. * **C. Ipratropium bromide:** This is a bronchodilator administered via inhalation. It is used to manage COPD and asthma but is not used systemically as a preanesthetic antisialagogue. * **D. Hyoscine (Scopolamine):** While it is an anticholinergic, it is a tertiary amine that easily crosses the BBB. It is more commonly used for its potent sedative and anti-emetic (motion sickness) properties but can cause "Central Anticholinergic Syndrome" (confusion/hallucinations), making it less ideal than Glycopyrrolate for routine use. **High-Yield Clinical Pearls for NEET-PG:** * **Drug of choice for intraoperative bradycardia:** Atropine (fastest onset). * **Antisialagogue potency:** Scopolamine > Glycopyrrolate > Atropine. * **Tachycardia potency:** Atropine > Glycopyrrolate > Scopolamine. * **Glycopyrrolate** is also co-administered with Neostigmine during the reversal of neuromuscular blockade to counteract Neostigmine’s muscarinic side effects (bradycardia and salivation).

Question 20: A 2-year-old child is scheduled for elective tonsillectomy and adenoidectomy. The mother reports the child has a runny nose. In which of the following situations would you proceed with the surgery?

A. Child is afebrile
B. Child is not actively wheezing
C. Child is having bilateral bronchial breath sounds (Correct Answer)
D. Child is alert and feeding normally

Explanation: ### Explanation The management of a pediatric patient with an **Upper Respiratory Tract Infection (URTI)** is a frequent dilemma in anesthesia. The primary goal is to distinguish between a "mild" URTI (safe to proceed) and a "severe" URTI (high risk of perioperative respiratory adverse events like laryngospasm or bronchospasm). **Why Option C is the Correct Answer:** This question likely contains a slight clinical paradox or requires identifying the most reassuring physical finding among the choices. In pediatric chest auscultation, **bilateral bronchial breath sounds** (in the absence of adventitious sounds like rales or rhonchi) can be a normal finding in young children due to their thin chest walls and the proximity of large airways to the stethoscope. If the child has a runny nose but the lungs are clear (even with loud, transmitted bronchial sounds), it suggests the infection is limited to the upper airway and hasn't progressed to the lower respiratory tract, making it safer to proceed. **Analysis of Incorrect Options:** * **Option A & B:** While being afebrile and not wheezing are positive signs, they are non-specific. A child can have a significant lower respiratory infection or pneumonia without an active wheeze or high fever at the moment of examination. * **Option D:** Being alert and feeding normally indicates the child is not "toxic," but it does not rule out active airway hyperreactivity, which is the chief concern for an elective tonsillectomy (an airway surgery). **Clinical Pearls for NEET-PG:** * **Criteria to Cancel Surgery:** Presence of purulent nasal discharge, fever (>38.5°C), productive cough, wheezing/rhonchi that does not clear with coughing, or signs of respiratory distress. * **Wait Period:** If an elective surgery is cancelled due to URTI, it should ideally be postponed for **4–6 weeks** to allow airway hyperreactivity to subside. * **Risk Factor:** Tonsillectomy itself is an independent risk factor for respiratory complications in a child with a URTI because the surgery involves the airway. * **Management:** If proceeding, use of an LMA is often preferred over an ETT to minimize glottic stimulation, and pre-treatment with bronchodilators may be considered.

Practice by Chapter

Preoperative Assessment Framework

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ASA Physical Status Classification

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Preoperative Laboratory Testing

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Cardiovascular Evaluation

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Pulmonary Evaluation

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Assessment of the Difficult Airway

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Medication Management

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NPO Guidelines

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Perioperative Anticoagulation Management

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Premedication

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Informed Consent

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Risk Stratification

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