Preoperative Evaluation and Management — MCQs
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According to current guidelines, how many hours before surgery should solids per oral be stopped?
A 65-year-old man with a history of severe COPD (chronic smoker), diabetes mellitus (on insulin and metformin), and hypertension (on antihypertensive medications), not on regular follow-up, is scheduled for emergency laparoscopic appendectomy. He experiences dyspnea on walking more than a few meters. According to the ASA physical status classification system, to which class would this patient be assigned?
Which of the following statements is true regarding preoperative evaluation of respiratory disease?
A homeless man is admitted unresponsive after being found by police on a park bench. He has no external signs of injury. An esophageal temperature probe records his core body temperature to be 34°C. Which of the following management options is not routinely indicated in this case?
How many days before surgery should lithium be stopped?
Elective dental extractions on a patient who has had a myocardial infarct two months prior are best:
Lithium potentiates the action of non-depolarizing muscle relaxants. How many days before administration of the muscle relaxant should lithium be stopped?
What is the ASA grading system used to assess?
A patient is on regular medications for co-existing medical problems. Which of the following drugs may be stopped safely with minimal risk of adverse effects before an abdominal surgery?
Which of the following drugs is NOT commonly used in pre-anesthetic medication?
Preoperative Evaluation and Management Indian Medical PG Practice Questions and MCQs
Question 91: According to current guidelines, how many hours before surgery should solids per oral be stopped?
- A. 4 hours
- B. 6 hours (Correct Answer)
- C. 8 hours
- D. 10 hours
Explanation: **Explanation:** The correct answer is **6 hours**. The primary goal of preoperative fasting (NPO status) is to reduce the volume and acidity of gastric contents, thereby minimizing the risk of **pulmonary aspiration of gastric contents**, a potentially fatal complication known as Mendelson’s Syndrome. **Why 6 hours is correct:** Current guidelines (ASA and ISA) recommend a minimum fasting period of **6 hours** for a "light meal" (e.g., toast and clear liquids) and for non-human milk or infant formula. This duration allows sufficient time for gastric emptying in healthy individuals. However, if the meal includes fatty or fried foods, the duration is typically extended to 8 hours. **Analysis of Incorrect Options:** * **A. 4 hours:** This is the recommended fasting time specifically for **breast milk** in infants, as it empties faster than solids or formula. It is insufficient for solid food. * **C. 8 hours:** While often practiced ("NPO after midnight"), 8 hours is specifically reserved for **heavy, fatty, or fried meals**. For a standard light solid meal, 6 hours is the guideline-defined minimum. * **D. 10 hours:** This is unnecessarily long and can lead to dehydration, hypoglycemia, and patient discomfort without providing additional safety benefits. **High-Yield Clinical Pearls for NEET-PG:** * **Clear Liquids:** Can be taken up to **2 hours** before surgery (e.g., water, fruit juices without pulp, carbonated beverages, black coffee). * **The "2-4-6-8 Rule":** * 2 hours: Clear liquids. * 4 hours: Breast milk. * 6 hours: Light meal/Infant formula/Non-human milk. * 8 hours: Fatty or fried foods. * **Exceptions:** Patients with delayed gastric emptying (Diabetes, pregnancy, obesity, or GERD) are often treated as "full stomachs" regardless of fasting time.
Question 92: A 65-year-old man with a history of severe COPD (chronic smoker), diabetes mellitus (on insulin and metformin), and hypertension (on antihypertensive medications), not on regular follow-up, is scheduled for emergency laparoscopic appendectomy. He experiences dyspnea on walking more than a few meters. According to the ASA physical status classification system, to which class would this patient be assigned?
- A. ASA Class 3E
- B. ASA Class 3
- C. ASA Class 4E (Correct Answer)
- D. ASA Class 4
Explanation: ### Explanation The **ASA Physical Status Classification System** is a clinical tool used to assess a patient's preoperative physical state and predict perioperative risk. **1. Why ASA Class 4E is correct:** * **ASA Class 4** is defined as a patient with a **severe systemic disease that is a constant threat to life**. In this case, the patient has severe COPD and experiences dyspnea after walking only a few meters. This indicates a very poor functional capacity and a disease state that significantly limits activity and poses an ongoing threat to survival. * **The "E" Modifier:** The patient is scheduled for an **emergency** laparoscopic appendectomy. According to ASA guidelines, the suffix "E" must be added to the classification for any surgery performed where a delay would significantly increase the threat to life or body part. **2. Why other options are incorrect:** * **ASA Class 3/3E:** This class represents severe systemic disease that is **not** a constant threat to life (e.g., stable COPD, controlled DM). This patient’s severe dyspnea at minimal exertion elevates him to Class 4. * **ASA Class 4 (without E):** While the physical status is correct, the classification is incomplete because it fails to account for the emergency nature of the surgery. **3. Clinical Pearls for NEET-PG:** * **ASA 1:** Healthy, non-smoking, no/minimal alcohol. * **ASA 2:** Mild systemic disease (e.g., smoker, well-controlled DM/HTN, obesity BMI 30-40). * **ASA 3:** Severe systemic disease, substantive functional limitations (e.g., stable angina, BMI >40, poorly controlled DM). * **ASA 5:** Moribund patient not expected to survive without the operation (e.g., ruptured AAA). * **ASA 6:** Declared brain-dead patient whose organs are being removed for donor purposes. * **High-Yield Tip:** Functional capacity (METs) is a key differentiator between ASA 3 and 4. Dyspnea at rest or minimal exertion usually points toward ASA 4.
Question 93: Which of the following statements is true regarding preoperative evaluation of respiratory disease?
- A. Assessment of pre-operative arterial blood gases
- B. Outcome depends upon blood gas and pulmonary function tests
- C. Involves physiotherapists and anaesthetists
- D. All of the above (Correct Answer)
Explanation: ***All of the above*** - Preoperative evaluation of respiratory disease is **comprehensive** and includes assessment of **arterial blood gases**, **pulmonary function tests**, and involvement of **multidisciplinary team**. - All components work together to optimize **perioperative outcomes** and reduce **respiratory complications** in high-risk patients. *Assessment of pre-operative arterial blood gases* - **ABG analysis** provides crucial information about **oxygenation**, **ventilation**, and **acid-base status** in patients with respiratory disease. - Helps identify **hypoxemia**, **hypercapnia**, and **respiratory acidosis** that may increase perioperative risk. *Outcome depends upon blood gas and pulmonary function tests* - **Pulmonary function tests** (spirometry, DLCO) help assess **respiratory reserve** and predict postoperative complications. - Combined with **ABG results**, these tests guide **risk stratification** and perioperative management decisions. *Involves physiotherapists and anaesthetists* - **Physiotherapists** provide preoperative **respiratory training**, **incentive spirometry**, and postoperative **chest physiotherapy**. - **Anesthetists** assess respiratory risk, plan appropriate **anesthetic techniques**, and optimize **ventilation strategies**.
Question 94: A homeless man is admitted unresponsive after being found by police on a park bench. He has no external signs of injury. An esophageal temperature probe records his core body temperature to be 34°C. Which of the following management options is not routinely indicated in this case?
- A. Cardiac monitoring
- B. Warmed peritoneal lavage (Correct Answer)
- C. Warmed intravenous fluids
- D. Intravenous dextrose
Explanation: **Explanation:** The patient presents with **mild hypothermia** (core temperature 32°C–35°C). The management of hypothermia is categorized based on severity and clinical stability. **1. Why "Warmed Peritoneal Lavage" is the correct answer:** Warmed peritoneal lavage is an **active internal (core) rewarming** technique. These invasive methods are reserved for **severe hypothermia (<28°C)** or patients with moderate hypothermia who are hemodynamically unstable or in cardiac arrest. At 34°C (mild hypothermia), the patient is typically managed with **passive rewarming** (blankets, warm room) and **active external rewarming** (forced-air warming blankets). Invasive lavage is not routinely indicated and carries risks of organ injury and infection. **2. Why the other options are incorrect:** * **Cardiac monitoring:** Essential because hypothermia increases myocardial irritability. Even mild hypothermia can lead to arrhythmias (like atrial fibrillation) or progress to life-threatening V-fib if the patient is handled roughly. * **Warmed intravenous fluids:** A standard treatment for all stages of hypothermia to prevent "afterdrop" (a further decline in core temperature as cold peripheral blood returns to the core) and to treat the "cold diuresis" induced dehydration. * **Intravenous dextrose:** Crucial in a homeless, unresponsive patient. Hypothermia often masks hypoglycemia, and glycogen stores are frequently depleted in this population due to malnutrition or alcohol use. **Clinical Pearls for NEET-PG:** * **J-wave (Osborn wave):** A characteristic ECG finding in hypothermia (positive deflection at the J-junction). * **Rewarming Shock:** Vasodilation during rewarming can lead to hypotension; hence, volume resuscitation is vital. * **Death:** A patient is not "dead" until they are **"warm and dead"** (rewarmed to 35°C without return of circulation).
Question 95: How many days before surgery should lithium be stopped?
- A. 1 day
- B. 2 days
- C. 3 days (Correct Answer)
- D. 4 days
Explanation: **Explanation:** **Correct Option: C (3 days)** Lithium is a mood stabilizer used primarily for bipolar disorder. It is recommended to be discontinued **72 hours (3 days)** prior to major elective surgery. The primary medical rationale is its narrow therapeutic index and its significant interaction with neuromuscular blocking agents (NMBAs). Lithium inhibits the release of acetylcholine and interferes with post-synaptic ion channels, thereby **prolonging the duration of action** of both depolarizing (succinylcholine) and non-depolarizing muscle relaxants. Furthermore, lithium can decrease anesthetic requirements (MAC) and increase the risk of cardiac arrhythmias and renal dysfunction if dehydration occurs perioperatively. **Analysis of Incorrect Options:** * **A & B (1–2 days):** While some guidelines suggest 24–48 hours for minor procedures, for the purpose of standardized exams like NEET-PG, 72 hours is the established gold standard to ensure complete clearance and stabilization of electrolyte-like interactions at the neuromuscular junction. * **D (4 days):** Discontinuing lithium for too long increases the risk of a relapse into a manic or depressive episode. Three days is considered the optimal balance between pharmacological safety and psychiatric stability. **High-Yield Clinical Pearls for NEET-PG:** * **Interaction:** Lithium **prolongs** the block of both Succinylcholine and Vecuronium/Rocuronium. * **Toxicity:** NSAIDs, ACE inhibitors, and Thiazide diuretics can increase lithium levels, leading to toxicity (ataxia, tremors, seizures). * **Restarting:** Lithium should be restarted postoperatively only when oral intake is stable and renal function/electrolyte balance is confirmed. * **ECG Changes:** Chronic lithium use may cause T-wave flattening or inversion (similar to hypokalemia).
Question 96: Elective dental extractions on a patient who has had a myocardial infarct two months prior are best:
- A. Performed under oral valium sedation
- B. Performed using an epinephrine-free local anesthetic
- C. Performed using both of the above
- D. Postponed until at least six months have elapsed (Correct Answer)
Explanation: **Explanation:** The primary concern in a post-myocardial infarction (MI) patient undergoing surgery is the risk of **Perioperative Reinfarction**. Statistics show that the risk of a recurrent MI is highest in the immediate post-infarct period and decreases over time. **1. Why Option D is correct:** Historically, the risk of reinfarction was approximately 30% if surgery was performed within 3 months of an MI, dropping to 15% between 3–6 months, and stabilizing at roughly 5–6% after **6 months**. While modern ACC/AHA guidelines suggest that elective surgery can be considered after 60 days (if no coronary intervention was done) or longer (if stents were placed), the "6-month rule" remains a classic, high-yield benchmark for NEET-PG questions regarding elective, non-urgent procedures like dental extractions to ensure maximum myocardial stability. **2. Why other options are incorrect:** * **Options A & B:** While oral sedation (Valium) can reduce anxiety-induced tachycardia and using epinephrine-free local anesthesia can prevent exogenous catecholamine-induced arrhythmias, these are **adjuncts** to safety. They do not mitigate the inherent physiological risk of reinfarction during the high-risk 0–6 month window. Safety is primarily time-dependent, not just technique-dependent. **Clinical Pearls for NEET-PG:** * **Highest Risk Period:** The risk of reinfarction is highest within the first 30 days post-MI. * **Gold Standard Timing:** For elective non-cardiac surgery, waiting **6 months** is the traditional teaching to reach the lowest baseline risk. * **Mortality:** Perioperative MI carries a high mortality rate (nearly 30–50%). * **Stent Considerations:** If a Bare Metal Stent (BMS) was placed, wait at least 30 days; for Drug-Eluting Stents (DES), wait at least 6 months (ideally 12) before elective surgery to avoid stent thrombosis.
Question 97: Lithium potentiates the action of non-depolarizing muscle relaxants. How many days before administration of the muscle relaxant should lithium be stopped?
- A. 1 day
- B. 2 days (Correct Answer)
- C. 3 days
- D. 4 days
Explanation: **Explanation:** **Underlying Medical Concept:** Lithium is a monovalent cation used primarily for bipolar disorder. In the context of anesthesia, lithium significantly **potentiates the effects of both depolarizing (Succinylcholine) and non-depolarizing muscle relaxants (NDMRs)**. The mechanism involves lithium’s ability to inhibit the release of acetylcholine at the neuromuscular junction and interfere with the synthesis of intracellular second messengers. Due to its narrow therapeutic index and the risk of prolonged neuromuscular blockade (leading to delayed recovery or respiratory depression), lithium should ideally be discontinued **48 hours (2 days)** prior to elective surgery. **Analysis of Options:** * **Option B (2 days) - Correct:** This aligns with the standard recommendation to stop lithium 48 hours before surgery to allow for adequate clearance and to minimize interactions with anesthetic agents. * **Option A (1 day):** 24 hours is often insufficient for complete clearance, especially in patients with borderline renal function, leaving the patient at risk for prolonged blockade. * **Options C & D (3 & 4 days):** While stopping lithium for longer would ensure clearance, it unnecessarily increases the risk of a relapse of psychiatric symptoms (mania or depression) without providing significant additional anesthetic benefit. **High-Yield Facts for NEET-PG:** * **ECG Changes:** Lithium can cause T-wave flattening or inversion (similar to hypokalemia). * **Drug Interactions:** NSAIDs, ACE inhibitors, and Thiazide diuretics increase lithium levels, potentially leading to toxicity. * **MAC Effect:** Lithium **decreases** the Minimum Alveolar Concentration (MAC) of inhalational anesthetics, meaning less anesthetic is required. * **Post-op:** Resume lithium as soon as oral intake and renal function are stable.
Question 98: What is the ASA grading system used to assess?
- A. Cardiac status
- B. Respiratory status
- C. Surgical patient risk factors (Correct Answer)
- D. Mental status
Explanation: The **ASA Physical Status Classification System** is a standardized tool used by anesthesiologists to categorize a patient’s physiological status and overall health before surgery. ### **Why the Correct Answer is Right** The ASA grading system assesses **surgical patient risk factors** by evaluating the severity of a patient’s systemic diseases. It serves as a predictor of perioperative morbidity and mortality. While it does not predict specific anesthetic risks, it provides a baseline of the patient's "fitness" for surgery. ### **Why Other Options are Wrong** * **Cardiac Status (A) & Respiratory Status (B):** While heart and lung diseases are major components of the ASA score (e.g., a recent MI or COPD), the ASA grade is a **global assessment** of all systemic systems, not limited to one organ. Specific tools like the *Goldman Index* or *NYHA Classification* are used for cardiac status. * **Mental Status (D):** Mental status is only a small part of the overall clinical picture and is not the primary focus of the ASA grading. ### **High-Yield Facts for NEET-PG** * **ASA I:** Normal healthy patient (non-smoking, minimal alcohol). * **ASA II:** Mild systemic disease (e.g., controlled HTN, DM, pregnancy, obesity BMI 30-40). * **ASA III:** Severe systemic disease with **functional limitations** (e.g., poorly controlled DM, COPD, morbid obesity BMI >40). * **ASA IV:** Severe systemic disease that is a **constant threat to life** (e.g., recent <3 months MI, CVA, or ongoing cardiac ischemia). * **ASA V:** Moribund patient not expected to survive without the operation (e.g., ruptured aneurysm). * **ASA VI:** Declared brain-dead patient whose organs are being removed for donor purposes. * **Suffix 'E':** Added to any class to denote an **Emergency** surgery (e.g., ASA IIE).
Question 99: A patient is on regular medications for co-existing medical problems. Which of the following drugs may be stopped safely with minimal risk of adverse effects before an abdominal surgery?
- A. Statins
- B. Beta blockers
- C. ACE inhibitors/ACE Receptor Blockers (Correct Answer)
- D. Steroids
Explanation: ### Explanation The perioperative management of chronic medications is crucial to ensure hemodynamic stability during anesthesia. **Why ACE Inhibitors (ACEIs) and Angiotensin Receptor Blockers (ARBs) are stopped:** The primary concern with ACEIs (e.g., Enalapril) and ARBs (e.g., Losartan) is **refractory hypotension** during the induction of general anesthesia. These drugs inhibit the Renin-Angiotensin-Aldosterone System (RAAS), which is a vital compensatory mechanism the body uses to maintain blood pressure when anesthetic agents cause vasodilation. If the RAAS is blocked, the resulting hypotension can be severe and resistant to common vasopressors like ephedrine, often requiring vasopressin. Therefore, they are typically withheld **24 hours prior to surgery**. **Analysis of Incorrect Options:** * **Beta-blockers:** These should **never** be stopped abruptly. Sudden withdrawal can lead to "rebound hypertension," tachycardia, and myocardial ischemia due to up-regulation of beta-receptors. * **Statins:** These are continued perioperatively. They have pleiotropic effects, including plaque stabilization and anti-inflammatory properties, which reduce the risk of postoperative cardiovascular events. * **Steroids:** Patients on long-term steroids may have a suppressed Hypothalamic-Pituitary-Adrenal (HPA) axis. Stopping them can trigger an **Addisonian crisis**. Instead, these patients often require "stress doses" of hydrocortisone perioperatively. **High-Yield Clinical Pearls for NEET-PG:** * **Continue:** Beta-blockers, Calcium Channel Blockers, Statins, Digoxin, and most psychiatric medications (except MAO inhibitors). * **Stop:** ACEIs/ARBs (24h before), Oral Hypoglycemics (morning of surgery), and Antiplatelets/Anticoagulants (timing depends on the specific drug, e.g., Aspirin 7 days, Clopidogrel 5 days). * **Insulin:** Long-acting insulin is usually continued at a reduced dose (e.g., 50-80%), while short-acting insulin is withheld.
Question 100: Which of the following drugs is NOT commonly used in pre-anesthetic medication?
- A. Diazepam
- B. Scopolamine
- C. Morphine
- D. Succinylcholine (Correct Answer)
Explanation: **Explanation:** The goal of **pre-anesthetic medication** is to allay anxiety, provide sedation, induce amnesia, and reduce secretions or gastric acidity before the induction of anesthesia. **Why Succinylcholine is the correct answer:** Succinylcholine is a **depolarizing neuromuscular blocking agent** (muscle relaxant). It has a very rapid onset (30–60 seconds) and a short duration of action (5–10 minutes). It is used exclusively for **induction and intubation** (to facilitate endotracheal tube placement) or for rapid sequence induction (RSI). It is never used as a premedication because it causes immediate paralysis and respiratory arrest, which requires the patient to be already unconscious and under direct airway management. **Analysis of other options:** * **Diazepam (A):** A benzodiazepine used as a pre-medicant for its **anxiolytic and sedative** properties. It also provides anterograde amnesia. * **Scopolamine (B):** An anticholinergic (antimuscarinic) agent used to **reduce salivary and bronchial secretions** (antisialogogue effect) and to provide significant sedation and amnesia. * **Morphine (C):** An opioid analgesic used in premedication to **provide basal analgesia**, especially if the patient is in pain preoperatively or if a painful procedure is anticipated. **High-Yield Clinical Pearls for NEET-PG:** * **Succinylcholine** is metabolized by **pseudocholinesterase** (plasma cholinesterase). Deficiency of this enzyme leads to prolonged apnea. * **Glycopyrrolate** is often preferred over Atropine/Scopolamine as an antisialogogue because it does not cross the blood-brain barrier (no CNS side effects). * **Midazolam** is the most common benzodiazepine used for premedication due to its rapid onset and shorter half-life compared to Diazepam.
Practice by Chapter
Preoperative Assessment Framework
Practice Questions
ASA Physical Status Classification
Practice Questions
Preoperative Laboratory Testing
Practice Questions
Cardiovascular Evaluation
Practice Questions
Pulmonary Evaluation
Practice Questions
Assessment of the Difficult Airway
Practice Questions
Medication Management
Practice Questions
NPO Guidelines
Practice Questions
Perioperative Anticoagulation Management
Practice Questions
Premedication
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Informed Consent
Practice Questions
Risk Stratification
Practice Questions
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