Preoperative Evaluation and Management — MCQs

Preoperative Evaluation and Management Indian Medical PG Practice Questions and MCQs

Question 71: A 40-year-old lady presents with a large left parietal convexity meningioma with perilesional edema. She is scheduled for surgery the next day. Which of the following pre-operative notes would be inappropriate to document?

A. Initiate anti-epileptic treatment if not already started.
B. Wash the head with antiseptic shampoo.
C. Document antibiotic sensitivity if applicable.
D. Stop steroids. (Correct Answer)

Explanation: **Explanation:** The correct answer is **D (Stop steroids)** because this action is contraindicated in the preoperative management of a patient with a brain tumor and perilesional edema. **1. Why "Stop steroids" is inappropriate:** Brain tumors, such as meningiomas, often cause **vasogenic edema** due to the breakdown of the blood-brain barrier. This increases intracranial pressure (ICP). **Corticosteroids (specifically Dexamethasone)** are the mainstay of treatment to reduce this edema and improve neurological status before surgery. Stopping steroids abruptly would worsen the edema, potentially leading to herniation or intraoperative brain swelling (tight brain). **2. Analysis of Incorrect Options:** * **Option A (Anti-epileptics):** Supratentorial tumors (like a parietal meningioma) carry a high risk of seizures. Prophylactic or therapeutic anti-epileptic drugs (AEDs) are standard to prevent perioperative seizures. * **Option B (Head wash):** Preoperative scalp hygiene with antiseptic shampoo (like Chlorhexidine) is a standard neurosurgical protocol to reduce the microbial load and prevent Surgical Site Infections (SSI). * **Option C (Antibiotic sensitivity):** Documenting allergies or sensitivities is a vital part of the WHO Surgical Safety Checklist to ensure safe administration of prophylactic antibiotics before the incision. **Clinical Pearls for NEET-PG:** * **Drug of Choice:** Dexamethasone is preferred in neurosurgery due to its high potency, long half-life, and minimal mineralocorticoid (salt-retaining) activity. * **Cushing’s Triad:** A sign of high ICP—Hypertension, Bradycardia, and Irregular Respiration. * **Mannitol:** Used intraoperatively to "relax" the brain by osmotic diuresis, but steroids are the primary choice for long-term vasogenic edema management.

Question 72: What is the minimum acceptable hematocrit value for elective oral surgery?

A. 11%
B. 18%
C. 23%
D. 30% (Correct Answer)

Explanation: **Explanation:** The correct answer is **30% (Option D)**. In the context of elective surgery, particularly oral and maxillofacial procedures, the traditional "Rule of 10 and 30" has long been the clinical benchmark. This rule states that for a patient to safely undergo elective surgery under general anesthesia, they should ideally have a **Hemoglobin (Hb) of at least 10 g/dL** and a **Hematocrit (Hct) of at least 30%**. **Why 30%?** Hematocrit represents the volume percentage of red blood cells in the blood. A level of 30% ensures adequate oxygen-carrying capacity and blood viscosity to maintain tissue perfusion and meet the increased metabolic demands during the perioperative period. While modern "restrictive" transfusion triggers (Hb <7 g/dL) are used in critical care, for **elective** procedures, maintaining these higher baseline values minimizes the risk of intraoperative myocardial ischemia and delayed wound healing. **Analysis of Incorrect Options:** * **11% and 18% (Options A & B):** These values represent severe anemia. At these levels, the oxygen delivery ($DO_2$) is critically compromised, posing a high risk of high-output heart failure and intraoperative hypoxia. * **23% (Option C):** This corresponds to a Hemoglobin of approximately 7-8 g/dL. While this may be an acceptable "trigger" for transfusion in a stable, hospitalized patient, it is below the recommended threshold for initiating an elective surgical procedure. **Clinical Pearls for NEET-PG:** * **The 1:3 Rule:** Hemoglobin and Hematocrit generally maintain a 1:3 ratio (e.g., Hb 10 g/dL ≈ Hct 30%). * **Exceptions:** In patients with compensated chronic anemia (e.g., Chronic Kidney Disease) or cyanotic heart disease, elective surgery may proceed with lower values after specialist clearance. * **NPO Guidelines:** Remember the **2-4-6-8 rule** (Clear liquids: 2h, Breast milk: 4h, Light meal/Infant formula: 6h, Fatty meal: 8h) as these are frequently tested alongside preoperative labs.

Question 73: A 38-year-old hypothyroid female patient presents for uterine fibroid excision. She is 5'5" and weighs 60 kg. She last ate at 8 PM the previous night and took her thyroxine tablet with a sip of water in the morning. If the surgery is scheduled to start at 8 AM, what is her estimated fluid deficit?

A. 1.5 L
B. 1.2 L (Correct Answer)
C. 1.4 L
D. 1.6 L

Explanation: ### Explanation The calculation of preoperative fluid deficit is a high-yield topic in Anesthesiology, based on the **4-2-1 Rule** (Holliday-Segar formula) for maintenance fluid requirements and the duration of fasting. **1. Step-by-Step Calculation:** * **Maintenance Fluid Requirement:** For a 60 kg patient: * First 10 kg: 10 × 4 mL/hr = 40 mL/hr * Next 10 kg: 10 × 2 mL/hr = 20 mL/hr * Remaining 40 kg: 40 × 1 mL/hr = 40 mL/hr * **Total Maintenance Rate:** 40 + 20 + 40 = **100 mL/hr** * **Fasting Duration:** The patient last ate at 8 PM and the surgery is at 8 AM, totaling **12 hours** of fasting. * **Fluid Deficit:** Maintenance Rate × Fasting Hours = 100 mL/hr × 12 hours = **1200 mL (1.2 L).** **2. Analysis of Options:** * **Option B (1.2 L) is correct** as it accurately reflects the product of the hourly maintenance requirement and the fasting interval. * **Options A, C, and D** are incorrect because they result from miscalculating the maintenance rate (e.g., using a flat 2 mL/kg/hr) or miscounting the fasting hours. **3. Clinical Pearls for NEET-PG:** * **Thyroxine Management:** Patients should continue thyroid medications on the morning of surgery with a sip of water to maintain a euthyroid state, as seen in this vignette. * **Deficit Replacement:** In clinical practice, the calculated deficit is typically replaced using the **50-25-25 rule**: 50% in the 1st hour of surgery, 25% in the 2nd hour, and 25% in the 3rd hour (in addition to maintenance and blood loss). * **NPO Guidelines:** While this patient fasted for 12 hours, standard ASA guidelines allow clear liquids up to 2 hours and a light meal up to 6 hours before induction.

Question 74: A 60-year-old hypertensive patient on angiotensin II receptor antagonists (losartan) is scheduled for hernia repair surgery. How should the antihypertensive medication be managed perioperatively?

A. Continue till the day of operation (Correct Answer)
B. Discontinue 24 hours preoperatively
C. Discontinue one week preoperatively
D. Administer in increased dosage on the day of operation

Explanation: ### Explanation **1. Why Option A is Correct:** The current consensus in perioperative medicine (supported by many recent guidelines) emphasizes maintaining hemodynamic stability. For most hypertensive patients, continuing antihypertensive medications—including **Angiotensin II Receptor Blockers (ARBs)** like Losartan and **ACE inhibitors**—until the morning of surgery is generally recommended. This prevents "rebound hypertension" and sympathetic surges during induction and intubation. While there is a theoretical risk of "ACE-inhibitor-associated hypotension" during induction, it is usually transient and easily managed with vasopressors or fluid boluses. **2. Why the Other Options are Incorrect:** * **Option B & C:** Discontinuing ARBs 24 hours or a week prior can lead to uncontrolled intraoperative hypertension. While some older protocols suggested withholding them 24 hours prior to avoid refractory hypotension, modern practice favors continuity to ensure better overall cardiovascular protection, especially in minor to moderate risk surgeries like hernia repair. * **Option D:** There is no clinical indication to increase the dosage. Increasing the dose preoperatively significantly raises the risk of profound, refractory intraoperative hypotension without providing additional benefit. **3. High-Yield Clinical Pearls for NEET-PG:** * **The "Continue" Rule:** Most chronic medications (Beta-blockers, Calcium Channel Blockers, Statins, and ARBs/ACEIs) should be continued on the day of surgery with a sip of water. * **The "Stop" Rule:** * **Diuretics:** Usually withheld on the day of surgery to avoid hypovolemia and electrolyte imbalances. * **Oral Hypoglycemics:** Withheld on the morning of surgery (patient is NPO). * **SGLT2 Inhibitors:** Stopped 3–4 days prior to avoid euglycemic ketoacidosis. * **Antiplatelets (Clopidogrel):** Ideally stopped 5–7 days prior (unless the risk of stent thrombosis is high). * **Beta-Blockers:** Never stop abruptly; doing so can cause reflex tachycardia and myocardial ischemia.

Question 75: What is the purpose of pre-anesthetic medication?

A. To decrease the dose of anesthetic drugs
B. To decrease post-operative complications
C. To relieve anxiety
D. All of the above (Correct Answer)

Explanation: The primary goal of pre-anesthetic medication (premedication) is to prepare the patient physically and psychologically for surgery, ensuring a smooth induction, maintenance, and recovery from anesthesia. **Explanation of Options:** * **To relieve anxiety (Anxiolysis):** This is a core objective. Psychological stress triggers a sympathetic surge (tachycardia, hypertension). Drugs like Benzodiazepines (e.g., Midazolam) are used to provide sedation and amnesia, making the patient more cooperative. * **To decrease the dose of anesthetic drugs:** Premedication with opioids (e.g., Fentanyl) or α2-agonists (e.g., Clonidine/Dexmedetomidine) provides basal analgesia and sedation. This synergistic effect reduces the Minimum Alveolar Concentration (MAC) of inhalational agents and the required dose of intravenous induction agents (Propofol/Thiopental), thereby increasing the safety margin. * **To decrease post-operative complications:** Premedication addresses specific risks. For example, H2-blockers or Proton Pump Inhibitors (PPIs) reduce gastric acidity to prevent aspiration pneumonitis (Mendelson’s Syndrome). Antiemetics (e.g., Ondansetron) reduce Post-Operative Nausea and Vomiting (PONV), and anticholinergics (e.g., Glycopyrrolate) prevent excessive secretions and vagal bradycardia. Since all these factors contribute to perioperative safety and patient comfort, **Option D** is the correct answer. **High-Yield Clinical Pearls for NEET-PG:** * **Midazolam:** Most common premedication for anxiolysis and anterograde amnesia. * **Mendelson’s Syndrome:** Risk is high if gastric pH <2.5 and volume >0.4 ml/kg (25 ml). * **Glycopyrrolate:** Preferred over Atropine as an antisialogogue because it does not cross the blood-brain barrier (quaternary ammonium) and causes less tachycardia. * **Clonidine:** Reduces anesthetic requirements and provides hemodynamic stability.

Question 76: Ringer lactate is a:

A. Isotonic crystalloid solution (Correct Answer)
B. Hypertonic crystalloid solution
C. Hypotonic crystalloid solution
D. Isotonic colloid solution

Explanation: **Explanation:** **Ringer’s Lactate (RL)**, also known as Hartmann's solution, is the most commonly used **isotonic crystalloid** in perioperative care. 1. **Why Option A is Correct:** An isotonic solution has an osmolarity similar to that of human plasma (~285–295 mOsm/L). The calculated osmolarity of RL is approximately **273 mOsm/L**. While technically slightly hypo-osmolar in a lab setting, it behaves as an **isotonic** solution clinically because it maintains the effective osmotic pressure across semi-permeable cell membranes, preventing significant fluid shifts between the intracellular and extracellular compartments. 2. **Why Other Options are Incorrect:** * **Hypertonic (B):** Solutions like 3% Saline or Mannitol have much higher osmolarity than plasma, causing water to move out of cells. * **Hypotonic (C):** Solutions like 0.45% Saline (Half-normal saline) have lower osmolarity, causing cells to swell. * **Colloid (D):** Colloids (e.g., Albumin, Hetastarch) contain large molecules that do not cross the capillary membrane. RL consists of small electrolytes (Sodium, Potassium, Calcium, Chloride) and Lactate, making it a crystalloid. **High-Yield Clinical Pearls for NEET-PG:** * **Composition:** Na⁺ (130), Cl⁻ (109), K⁺ (4), Ca²⁺ (3), and Lactate (28) in mEq/L. * **Metabolism:** The lactate in RL is converted by the **liver** into bicarbonate, making it useful in treating metabolic acidosis. * **Contraindications:** * Avoid in **Traumatic Brain Injury (TBI)** as its slight hypo-osmolarity can worsen cerebral edema. * Do not co-administer with **blood transfusions** in the same IV line; the Calcium in RL can bind with the Citrate anticoagulant in blood bags, leading to clot formation. * Use cautiously in severe liver failure (impaired lactate metabolism).

Question 77: What are the benefits of stopping smoking before surgery, excluding one?

A. Better wound healing
B. Better mucociliary clearance
C. Better bone healing
D. Less risk of malignancies associated with smoking (Correct Answer)

Explanation: The goal of preoperative smoking cessation is to mitigate **immediate perioperative risks** and improve surgical outcomes. **Explanation of the Correct Answer:** **Option D** is the correct answer because, while smoking cessation reduces the long-term risk of developing cancer, this is a **chronic health benefit** rather than a perioperative surgical benefit. In the context of preoperative evaluation, we focus on physiological changes that occur within days to weeks to reduce surgical complications. Reducing the risk of malignancy requires years of abstinence and does not impact the immediate success of a surgical procedure. **Analysis of Incorrect Options:** * **A. Better wound healing:** Smoking causes peripheral vasoconstriction (via nicotine) and reduces oxygen delivery to tissues (via carboxyhemoglobin). Stopping smoking improves tissue oxygenation and collagen synthesis, significantly reducing the risk of wound dehiscence and infection. * **B. Better mucociliary clearance:** Smoking paralyzes the cilia in the airway. Cessation for at least **4–8 weeks** allows the mucociliary escalator to recover, facilitating the clearance of secretions and reducing postoperative pulmonary complications (PPC) like atelectasis and pneumonia. * **C. Better bone healing:** Nicotine is toxic to osteoblasts and inhibits angiogenesis. Preoperative cessation is specifically emphasized in orthopedic surgeries to prevent non-union of fractures and improve graft integration. **High-Yield NEET-PG Pearls:** * **12–24 hours:** Carboxyhemoglobin levels normalize, and the oxygen dissociation curve shifts back to the right (improving tissue oxygen delivery). * **48–72 hours:** Ciliary function begins to improve; however, sputum production may temporarily increase. * **4–8 weeks:** The "Gold Standard" duration to significantly reduce the incidence of postoperative respiratory complications. * **Nicotine effects:** Increases HR, BP, and myocardial oxygen demand (Sympathomimetic). * **Carbon Monoxide (CO) effects:** Reduces oxygen-carrying capacity and causes a leftward shift of the Hb-O2 curve.

Question 78: A patient presents with hypovolemia and a serum sodium level of 154 mEq/L. What is the initial treatment recommended?

A. Normal saline (Correct Answer)
B. Half normal saline with 5% dextrose
C. Dextran 40
D. Ringer's lactate

Explanation: ### Explanation **Correct Answer: A. Normal Saline (0.9% NaCl)** **1. Why Normal Saline is Correct:** The patient presents with **hypovolemic hypernatremia** (Sodium >145 mEq/L). In any patient with hypovolemia, the **initial priority is the restoration of intravascular volume** and hemodynamic stability over the correction of the electrolyte abnormality. Normal Saline (NS) is an isotonic crystalloid. Although it contains 154 mEq/L of sodium, it is "hypotonic" relative to this patient’s serum (154 mEq/L). It effectively expands the extracellular fluid (ECF) volume and improves tissue perfusion. Once hemodynamic stability is achieved, the fluid can be switched to hypotonic solutions to correct the free water deficit. **2. Why the Other Options are Incorrect:** * **B. Half normal saline (0.45% NaCl) with 5% Dextrose:** This is a hypotonic solution. While it is used to treat hypernatremia, using it in a *hypovolemic* patient can cause a rapid shift of water into the intracellular space, failing to expand the intravascular volume adequately and potentially worsening hypotension. * **C. Dextran 40:** This is a colloid. While it expands volume, it is not the first-line treatment for simple hypovolemia and carries risks of anaphylaxis and acute kidney injury. * **D. Ringer's Lactate (RL):** RL is an isotonic crystalloid (Sodium ~130 mEq/L). While it can be used for resuscitation, NS is traditionally preferred in the initial management of severe hypernatremia to avoid a too-rapid drop in serum osmolarity, which could lead to cerebral edema. **3. Clinical Pearls for NEET-PG:** * **Rule of Thumb:** Treat the **Volume** first, then the **Concentration**. * **Rate of Correction:** In chronic hypernatremia, do not lower serum sodium faster than **0.5 mEq/L/hr** (or 10–12 mEq/L in 24 hours) to prevent **Cerebral Edema**. * **Formula for Free Water Deficit:** $0.6 \times \text{Body Weight (kg)} \times [(\text{Current Na}^+ / \text{Desired Na}^+) - 1]$. * **Diabetes Insipidus:** A common cause of hypernatremia in neurosurgical anesthesia; treated with Desmopressin (Vasopressin).

Question 79: What does the ASA grading system evaluate in anesthesia?

A. Mental status
B. Physical status (Correct Answer)
C. Respiratory status
D. Socio-economic status

Explanation: **Explanation:** The **ASA (American Society of Anesthesiologists) Physical Status Classification System** is a standardized tool used to assess a patient's overall health and physiological state before surgery. It is designed to categorize patients based on their systemic health and comorbidities, which helps in predicting perioperative risks. **Why Physical Status is Correct:** The ASA grading focuses on the severity of systemic diseases. It ranges from **ASA I** (a normal healthy patient) to **ASA VI** (a declared brain-dead patient whose organs are being removed for donor purposes). The addition of an **'E'** suffix denotes an emergency procedure. It is a measure of "physical status" rather than specific organ function or surgical complexity. **Why Other Options are Incorrect:** * **Mental Status:** While a patient's neurological state is assessed during the pre-anesthetic check-up (PAC), it is not the primary basis of the ASA grade. * **Respiratory Status:** This is a component of the physical status (e.g., COPD or Asthma), but the ASA grade is a global assessment of all systemic diseases, not just the respiratory system. * **Socio-economic Status:** This has no clinical bearing on the ASA classification, which is strictly medical. **High-Yield Clinical Pearls for NEET-PG:** * **ASA I:** Healthy, non-smoking, no/minimal alcohol. * **ASA II:** Mild systemic disease (e.g., controlled HTN, controlled DM, BMI 30-40, social smoker). * **ASA III:** Severe systemic disease with functional limitations (e.g., poorly controlled DM, BMI >40, history of MI >3 months ago). * **ASA IV:** Severe systemic disease that is a constant threat to life (e.g., recent MI <3 months, ongoing ischemia, sepsis). * **ASA V:** Moribund patient not expected to survive without the operation. * **Note:** ASA grade is a subjective assessment of physical status and does **not** directly measure "anesthetic risk," though it correlates with it.

Question 80: A 60-year-old woman with a history of diabetes, hypertension, and dyspnea on exertion undergoes pre-anesthetic evaluation for cataract repair. Her ECG shows normal sinus rhythm with left axis deviation. What is the recommended approach for this patient?

A. Order a treadmill test for further cardiac evaluation.
B. Perform 2D echocardiography.
C. No further testing is required; proceed with surgery. (Correct Answer)
D. Declare the patient unfit for surgery.

Explanation: ### Explanation **1. Why Option C is Correct:** The decision-making process for preoperative cardiac evaluation is guided by the **ACC/AHA guidelines**, which prioritize the **surgical risk** and the patient’s **functional capacity**. * **Low-Risk Surgery:** Cataract surgery is classified as a "low-risk" procedure (risk of major adverse cardiac events <1%). * **Clinical Management:** For low-risk surgeries, even if the patient has clinical risk factors (diabetes, hypertension) or poor functional capacity (dyspnea on exertion), further cardiac testing (like TMT or Echo) does not change the perioperative management or outcome. Therefore, the patient can proceed to surgery without additional investigations. **2. Why Other Options are Incorrect:** * **Option A (TMT):** Stress testing is only indicated for patients undergoing **elevated-risk surgery** (vascular or intermediate risk) who have **poor functional capacity** (<4 METs) and where the results would change management. It is unnecessary for cataract repair. * **Option B (2D Echo):** Routine preoperative echocardiography is not recommended unless there is a suspicion of new or worsening valvular heart disease or heart failure. Left axis deviation on ECG is a common, non-specific finding in hypertensive patients and is not an indication for Echo in this context. * **Option D (Unfit):** The patient is not "unfit." Her comorbidities are chronic, and the surgical stress of cataract repair (usually under local/topical anesthesia) is minimal. **3. Clinical Pearls for NEET-PG:** * **METS (Metabolic Equivalents):** If a patient can climb two flights of stairs or walk 4 mph, they have >4 METS (Good functional capacity). * **Low-Risk Procedures:** Cataract, endoscopy, superficial surgery, and breast surgery. * **ECG Findings:** A preoperative ECG is not mandatory for asymptomatic patients undergoing low-risk surgery, regardless of age. * **Goldman’s Index/Revised Cardiac Risk Index (RCRI):** Used to predict perioperative cardiac risk, but surgical risk (the procedure itself) is the first branch in the decision tree.

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

Practice Questions

Informed Consent

Practice Questions

Risk Stratification

Practice Questions

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