Preoperative Evaluation and Management Practice Questions

Q: Which is the most potent antiemetic agent used in the preoperative period?

Hyoscine. ### Explanation The correct answer is **Hyoscine (Scopolamine)**. **Why Hyoscine is the Correct Choice:** Hyoscine is a tertiary amine anticholinergic that effectively crosses the blood-brain barrier. It acts primarily on the **muscarinic receptors in the vestibular apparatus** and the nucleus tractus solitarius. Among the options provided, it is the most potent agent for preventing **Postoperative Nausea and Vomiting (PONV)**, particularly when motion sickness or vestibular stimulation is a factor. In clinical practice, it is often administered as a transdermal patch (1.5 mg) preoperatively to provide sustained antiemetic effects for up to 72 hours. **Analysis of Incorrect Options:** * **Glycopyrrolate:** A quaternary ammonium compound that does **not** cross the blood-brain barrier. While it is excellent for reducing secretions (antisialagogue), it has no central antiemetic effect. * **Atropine:** A tertiary amine that crosses the blood-brain barrier but has minimal effect on the vomiting center compared to Hyoscine. It is primarily used to treat bradycardia or as an antisialagogue. * **Metoclopramide:** A dopamine (D2) antagonist. While it has prokinetic and antiemetic properties, its potency in preventing PONV is significantly lower than Hyoscine or 5-HT3 antagonists (like Ondansetron). **High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice for Motion Sickness:** Hyoscine (Scopolamine). * **Antisialagogue Potency:** Scopolamine > Glycopyrrolate > Atropine. * **Sedative Potency:** Scopolamine > Atropine > Glycopyrrolate (Zero). * **Tachycardia Potency:** Atropine > Glycopyrrolate > Scopolamine. * **Central Anticholinergic Syndrome:** Caused by Atropine/Hyoscine; treated with **Physostigmine** (a tertiary amine acetylcholinesterase inhibitor).

Q: Which of the following statements regarding preoperative modification of drugs is incorrect?

Low-dose aspirin should be stopped 7 days before surgery.. **Explanation:** The correct answer is **B** because the current clinical guidelines recommend that **low-dose aspirin (75–150 mg)** should generally be **continued** throughout the perioperative period, especially in patients with coronary artery disease or drug-eluting stents. The risk of major adverse cardiac events (MACE) from stopping aspirin often outweighs the risk of surgical bleeding. It is only stopped (usually for 7–10 days) in specific "closed-space" surgeries where even minor bleeding is catastrophic, such as intracranial, posterior chamber of the eye, or deep spinal procedures. **Analysis of other options:** * **A. Lithium:** It is traditionally stopped **48–72 hours** before major surgery because it prolongs the action of neuromuscular blocking agents and carries a risk of toxicity due to perioperative dehydration and electrolyte shifts. * **C. Tricyclic Antidepressants (TCAs):** These can be **continued** until the day of surgery. However, the anesthesiologist must be cautious as TCAs increase sympathetic tone, potentially leading to exaggerated responses to indirect-acting sympathomimetics (like ephedrine) and an increased risk of arrhythmias. * **D. Oral Anticoagulants (e.g., Warfarin):** These are typically stopped **4–5 days** prior to surgery to allow the INR to normalize (<1.5). High-risk patients may require "bridging therapy" with Heparin. **High-Yield Clinical Pearls for NEET-PG:** * **Continue:** Beta-blockers, Calcium channel blockers, Statins, and most Antiepileptics. * **Stop on the day of surgery:** ACE inhibitors and ARBs (due to risk of refractory hypotension), and Oral Hypoglycemic Agents (Metformin is stopped 24–48 hours prior to avoid lactic acidosis). * **MAO Inhibitors:** Traditionally stopped 2 weeks prior, but modern practice often allows continuation with strict avoidance of Pethidine (risk of Serotonin Syndrome).

Q: Which of the following is NOT part of routine preoperative preparation?

Erythropoietin. **Explanation:** The goal of routine preoperative preparation is to alleviate patient anxiety, provide sedation, and minimize autonomic reflexes or secretions. **Why Erythropoietin is the correct answer:** Erythropoietin is a glycoprotein hormone that stimulates red blood cell production. It is **not** a routine preoperative medication. Its use is strictly limited to specific clinical scenarios, such as patients with chronic kidney disease or those undergoing major elective surgery with anticipated high blood loss who refuse blood transfusions (e.g., Jehovah’s Witnesses). It requires weeks to be effective and carries risks of hypertension and thromboembolism, making it unsuitable for routine immediate preoperative use. **Why the other options are incorrect:** * **Diazepam & Midazolam (Benzodiazepines):** These are the most common agents used for **pre-anesthetic medication**. They provide anxiolysis and anterograde amnesia. Midazolam is preferred due to its shorter half-life and water solubility (less pain on injection). * **Atropine (Anticholinergic):** While no longer used "universally" for every patient, it remains a standard component of preoperative preparation to reduce salivary and bronchial secretions (antisialagogue effect) and to prevent reflex bradycardia during induction or surgery. **High-Yield NEET-PG Pearls:** * **Ideal time for Pre-medication:** Usually 60–90 minutes before induction. * **Midazolam:** Most common pre-medicant; provides excellent amnesia. * **Glycopyrrolate:** Often preferred over Atropine as an antisialagogue because it does not cross the blood-brain barrier (no central anticholinergic syndrome). * **Aspiration Prophylaxis:** Routine in "at-risk" patients using H2 blockers (Ranitidine) or Proton Pump Inhibitors (Pantoprazole) and prokinetics (Metoclopramide).

Q: A 65-year-old man with a history of myocardial infarction is scheduled for elective cholecystectomy. His weight is 73 kg and height is 6'2". His packed cell volume is 35%. What is the maximal allowable blood loss for the procedure?

780ml. ### Explanation The **Maximal Allowable Blood Loss (MABL)** is the amount of blood a patient can lose before their hemoglobin/hematocrit falls below a safe threshold, necessitating a blood transfusion. To calculate MABL, use the following formula: **MABL = [EBV × (Hct₀ - Hct_f)] / Hct_avg** 1. **Estimate Blood Volume (EBV):** For an adult male, EBV is approximately **70 ml/kg**. * EBV = 73 kg × 70 ml/kg = **5,110 ml**. 2. **Identify Hematocrit Values:** * Initial Hematocrit (**Hct₀**) = 35% (given). * Minimum acceptable Hematocrit (**Hct_f**): In a 65-year-old with a history of Myocardial Infarction (MI), the target hematocrit is generally **30%** to ensure adequate oxygen delivery to the myocardium. 3. **Calculate Average Hematocrit (Hct_avg):** (35 + 30) / 2 = **32.5%**. 4. **Final Calculation:** * MABL = [5,110 × (35 - 30)] / 32.5 * MABL = [5,110 × 5] / 32.5 = 25,550 / 32.5 ≈ **786 ml**. * The closest option is **780 ml (Option D)**. --- ### Analysis of Incorrect Options * **Options A, B, and C:** These values result from using incorrect EBV constants (e.g., 60 or 65 ml/kg) or assuming a lower "trigger" hematocrit (e.g., 21% or 24%). In a patient with ischemic heart disease, a higher trigger (30%) is mandatory, leading to a lower allowable loss than in a healthy young adult. --- ### High-Yield Clinical Pearls for NEET-PG * **EBV Constants:** Premature (95 ml/kg), Full-term neonate (85 ml/kg), Infant (80 ml/kg), Adult Male (70 ml/kg), Adult Female (65 ml/kg). * **Transfusion Trigger:** While 7 g/dL (Hct 21%) is the standard trigger for healthy patients, **10 g/dL (Hct 30%)** is the threshold for those with significant cardiopulmonary disease or elderly patients. * **Fluid Replacement:** Replace blood loss with crystalloids at a **3:1 ratio** or colloids/blood at a **1:1 ratio**.

Q: A 35-year-old woman with type 2 diabetes treated with metformin, anemia due to menorrhagia, and a BMI of 40, is scheduled for elective surgery for a large ovarian tumor. What ASA physical status classification would this patient be assigned?

ASA 3. ### **Explanation** The correct answer is **ASA 3**. The **ASA Physical Status Classification System** is a clinical tool used to assess a patient's preoperative physical state and predict perioperative risk. **Why ASA 3 is correct:** ASA 3 is defined as a patient with **severe systemic disease** that is not life-threatening but causes functional limitations. This patient has multiple significant comorbidities: 1. **Morbid Obesity:** A BMI of $\geq 40$ is automatically classified as ASA 3. 2. **Type 2 Diabetes:** While controlled DM is ASA 2, the presence of multiple systemic issues (obesity + anemia + DM) pushes the patient into a higher risk category. 3. **Symptomatic Anemia:** Anemia due to menorrhagia, especially if severe enough to require surgery, contributes to systemic physiological stress. **Why other options are incorrect:** * **ASA 1:** Reserved for a normal, healthy, non-smoking patient with minimal or no alcohol use. * **ASA 2:** A patient with mild systemic disease without substantive functional limitations (e.g., BMI 30–39, well-controlled DM/HTN, or a smoker). This patient’s BMI of 40 exceeds this category. * **ASA 4:** A patient with severe systemic disease that is a **constant threat to life** (e.g., recent MI <3 months, ongoing cardiac ischemia, or end-stage renal disease not undergoing regular dialysis). --- ### **High-Yield Clinical Pearls for NEET-PG** * **BMI Thresholds:** BMI 30–39.9 is **ASA 2**; BMI $\geq 40$ is **ASA 3**. * **Pregnancy:** A healthy pregnant woman is always classified as **ASA 2**. * **The "E" Suffix:** If the surgery is an emergency, the letter 'E' is added to the classification (e.g., ASA 3E). * **ASA 5:** A moribund patient who is not expected to survive without the operation (e.g., ruptured abdominal aortic aneurysm). * **ASA 6:** A declared brain-dead patient whose organs are being removed for donor purposes.

Q: A female patient is posted for breast lumpectomy and is taking herbal medicines. What advice should be given regarding pre-operative orders?

Advise to stop herbal medication 2 weeks prior to surgery. **Explanation:** The correct management for patients taking herbal supplements prior to elective surgery is to **discontinue them at least 2 weeks before the procedure**. This recommendation, supported by the American Society of Anesthesiologists (ASA), is based on the potential for herbal medicines to interfere with anesthesia and surgical outcomes. **Why Option B is Correct:** Herbal medications are not regulated as strictly as pharmaceuticals and can have significant perioperative side effects, including: * **Coagulopathy:** Supplements like Garlic, Ginger, Ginkgo biloba, and Ginseng (the "4 Gs") increase bleeding risk. * **Cardiovascular Instability:** Ephedra can cause tachycardia and hypertension, while Ginseng may cause hypoglycemia. * **Prolonged Sedation:** Valerian and St. John’s Wort can potentiate the effects of anesthetic agents or induce cytochrome P450 enzymes, altering drug metabolism. A 2-week window allows for the clearance of these substances and the reversal of their physiological effects. **Why Other Options are Incorrect:** * **Option A:** Deferring surgery indefinitely is unnecessary if the patient can safely stop the supplement for the required duration. * **Option C & D:** Continuing these medications or ignoring them poses significant risks, such as intraoperative hemorrhage, delayed emergence from anesthesia, or unpredictable drug interactions. **High-Yield Clinical Pearls for NEET-PG:** * **St. John’s Wort:** Potent inducer of CYP3A4; reduces the efficacy of drugs like cyclosporine and warfarin. * **Ginkgo Biloba:** Potent inhibitor of platelet-activating factor (PAF); must be stopped to prevent surgical site hematomas. * **Ephedra (Ma Huang):** Should be stopped 24 hours prior due to risk of intraoperative arrhythmias. * **Garlic:** Irreversibly inhibits platelet aggregation; effects last 7–10 days.

Q: Preanesthetic medication comprises of all the following, except:

Lignocaine. **Explanation:** Preanesthetic medication refers to the administration of drugs before the induction of anesthesia to reduce anxiety, provide sedation, prevent autonomic reflex responses, and minimize the risk of aspiration. **Why Lignocaine is the Correct Answer:** Lignocaine is a local anesthetic and Class Ib anti-arrhythmic agent. While it is used intraoperatively (e.g., to blunt the pressor response during intubation or as part of a multimodal analgesic infusion), it is **not** classified as a standard preanesthetic medication. Its primary role is procedural or therapeutic rather than preparatory. **Analysis of Other Options:** * **Diazepam:** A benzodiazepine used as a sedative-hypnotic to provide anxiolysis and anterograde amnesia. It is a classic premedicant. * **Atropine:** An anticholinergic (antimuscarinic) agent used to reduce salivary and bronchial secretions and to prevent vagally-mediated bradycardia during surgery. * **Metoclopramide:** A prokinetic and antiemetic agent. It is used in premedication to increase lower esophageal sphincter tone and promote gastric emptying, reducing the risk of aspiration pneumonitis (Mendelson’s Syndrome). **High-Yield Clinical Pearls for NEET-PG:** * **Mendelson’s Syndrome:** Aspiration pneumonitis characterized by a gastric volume >25 ml and pH <2.5. Premedication with Metoclopramide and H2 blockers (Ranitidine) helps mitigate this. * **Glycopyrrolate vs. Atropine:** Glycopyrrolate is often preferred over Atropine as a premedicant because it does not cross the blood-brain barrier (quaternary ammonium), causing less tachycardia and no central anticholinergic syndrome. * **Midazolam:** Currently the most common benzodiazepine used for premedication due to its rapid onset and shorter duration compared to Diazepam.

Question 1

Which is the most potent antiemetic agent used in the preoperative period?

Accepted Answer

Hyoscine

Answer

Glycopyrrolate

Answer

Atropine

Answer

Metoclopramide

Question 2

Which of the following statements regarding preoperative modification of drugs is incorrect?

Accepted Answer

Low-dose aspirin should be stopped 7 days before surgery.

Answer

Lithium should be stopped 2-3 days before surgery.

Answer

Tricyclic antidepressants can be continued until the day of operation.

Answer

Oral anticoagulants should be stopped 4 days before surgery.

Question 3

Which of the following patients should have their surgery deferred for further cardiac evaluation?

Accepted Answer

A 55-year-old female patient with Mobitz type 2 heart block rhythm.

Answer

A 60-year-old chronic smoker and diabetic with uncontrolled blood sugar and hypertension (BP=159/100).

Answer

A 70-year-old male patient with congestive heart failure who has a history of dyspnea on exertion.

Answer

A 45-year-old female patient who has shortness of breath while climbing upstairs.

Question 4

Which of the following is NOT part of routine preoperative preparation?

Accepted Answer

Erythropoietin

Answer

Diazepam

Answer

Midazolam

Answer

Atropine

Question 5

A patient has an ASA score of 3. What does this score indicate regarding their systemic disease and activity limitations?

Accepted Answer

Severe systemic disease that limits activity but is not incapacitating.

Answer

Mild systemic disease with no limitation of activity.

Answer

Moribund state with an expected survival of less than 24 hours, even with surgery.

Answer

Incapacitating systemic disease that poses a threat to life.

Question 6

A 65-year-old man with a history of myocardial infarction is scheduled for elective cholecystectomy. His weight is 73 kg and height is 6'2". His packed cell volume is 35%. What is the maximal allowable blood loss for the procedure?

Accepted Answer

780ml

Answer

600ml

Answer

680ml

Answer

700ml

Question 7

A 30-year-old man is scheduled for a laparoscopic cholecystectomy for biliary colic. He reports a family history of prolonged paralysis during general anesthesia. Which of the following medications should be avoided during his procedure?

Accepted Answer

Succinylcholine

Answer

Vecuronium

Answer

Pancuronium

Answer

Etomidate

Question 8

A 35-year-old woman with type 2 diabetes treated with metformin, anemia due to menorrhagia, and a BMI of 40, is scheduled for elective surgery for a large ovarian tumor. What ASA physical status classification would this patient be assigned?

Accepted Answer

ASA 3

Answer

ASA 1

Answer

ASA 2

Answer

ASA 4

Question 9

A female patient is posted for breast lumpectomy and is taking herbal medicines. What advice should be given regarding pre-operative orders?

Accepted Answer

Advise to stop herbal medication 2 weeks prior to surgery

Answer

Defer surgery

Answer

Continue the herbal medicine till the day of surgery

Answer

No specific advice regarding herbal medication is needed

Question 10

Preanesthetic medication comprises of all the following, except:

Accepted Answer

Lignocaine

Answer

Diazepam

Answer

Atropine

Answer

Metoclopramide

Preoperative Evaluation and Management — MCQs

Preoperative Evaluation and Management — MCQs

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