Preoperative Risk Assessment — MCQs
Which pre-operative investigation is recommended before surgical procedures in a patient on warfarin therapy?
Most sensitive method of monitoring cardiovascular ischemia in the perioperative period is -
Which one of the following is not a component of THORACOSCORE?
Match the following drugs in Column A with their contraindications in Column B. | Column A | Column B | | :-- | :-- | | 1. Morphine | 1. QT prolongation | | 2. Amiodarone | 2. Thromboembolism | | 3. Vigabatrin | 3. Pregnancy | | 4. Estrogen preparations | 4. Head injury |
Which of the following is not a risk factor for postoperative pulmonary complication?
Preoperative investigations done prior to surgery depend upon which of the following? 1. Type of surgery 2. Patient origin 3. Patient comorbidities 4. Experience of surgeon
Postoperative pulmonary complications are seen/expected in all except:
Thyroid storm during surgery is due to?
A patient posted for Lap Cholecystectomy had drug eluting stent placed two years back. Patient has no symptoms since then. Which of the following set of investigation should be done in this patient?
Warfarin to be stopped how many days before surgery?
Preoperative Risk Assessment Indian Medical PG Practice Questions and MCQs
Question 1: Which pre-operative investigation is recommended before surgical procedures in a patient on warfarin therapy?
- A. International Normalized Ratio (INR) (Correct Answer)
- B. Partial Thromboplastin Time (PTT)
- C. Clotting Time
- D. Differential Count
Explanation: ***International Normalized Ratio (INR)*** - The **INR** is specifically used to monitor the effectiveness of **warfarin** therapy, as it standardizes the prothrombin time (PT) for variations in thromboplastin reagents. - Before surgery, an INR measurement helps assess the patient's **coagulation status** and guides decisions on temporary cessation or bridging therapy to minimize bleeding risk. *Partial Thromboplastin Time (PTT)* - **PTT** primarily measures the **intrinsic and common pathways** of coagulation and is used to monitor **heparin** therapy, not warfarin. - While prolonged in some bleeding disorders, it is not the standard test for assessing warfarin's anticoagulant effect. *Clotting Time* - **Clotting time** is a very general and less precise measure of overall coagulation that is **rarely used** in modern clinical practice due to its low sensitivity and specificity. - It does not offer sufficient detail or standardization to guide pre-operative management for patients on warfarin. *Differential Count* - A **differential count** measures the different types of **white blood cells** within a blood sample and is used to diagnose infections, inflammatory conditions, or hematologic disorders. - It provides no information about a patient's coagulation status or the effects of anticoagulant medications like warfarin.
Question 2: Most sensitive method of monitoring cardiovascular ischemia in the perioperative period is -
- A. NIBP
- B. ECG
- C. Pulse oximeter
- D. TEE (Correct Answer)
Explanation: ***TEE*** - **Transesophageal echocardiography (TEE)** is the most sensitive method for detecting perioperative myocardial ischemia because it can visualize **regional wall motion abnormalities** and changes in **ventricular function** much earlier than ECG. - **Ischemia** directly impairs the contractility of the affected myocardium, leading to subtle changes in wall motion that TEE can identify. *NIBP* - **Non-invasive blood pressure (NIBP)** monitoring can detect **hemodynamic changes** (like hypotension or hypertension) that may precede or accompany ischemia. - However, these changes are **non-specific** and occur relatively late, making NIBP a less sensitive indicator of early ischemia. *ECG* - **Electrocardiography (ECG)** monitors the electrical activity of the heart and can detect **ST-segment changes** indicative of ischemia. - While useful, ECG changes may appear later than wall motion abnormalities, and **silent ischemia** can be missed if the leads are not optimally placed or if the ischemia does not produce significant electrical changes. *Pulse oximeter* - A **pulse oximeter** measures **oxygen saturation** in the peripheral blood. - It is primarily used to assess **respiratory function** and tissue oxygenation, and it does not directly monitor myocardial ischemia or cardiac function.
Question 3: Which one of the following is not a component of THORACOSCORE?
- A. Performance status
- B. Complication of surgery (Correct Answer)
- C. Priority of surgery
- D. ASA grading
Explanation: ***Complication of surgery*** - THORACOSCORE is a **risk prediction model** for thoracic surgery used to estimate the *probability of mortality and significant morbidity*, but it does not account for the complications of surgery itself as a component. - The score uses **pre-operative patient characteristics** and co-morbidities to predict outcomes, not post-operative events. *Performance status* - **Performance status**, such as the **ECOG scale**, is a crucial component of THORACOSCORE, reflecting the patient's general health and functional capacity prior to surgery. - A lower performance status (indicating poorer functional ability) increases the predicted risk in THORACOSCORE. *Priority of surgery* - The **priority of surgery** (e.g., elective, urgent, emergency) is an important factor in THORACOSCORE, as emergency procedures generally carry a higher risk. - This variable helps to capture the urgency and associated physiological stress on the patient at the time of presentation for surgery. *ASA grading* - The **American Society of Anesthesiologists (ASA) physical status classification system** is a component of THORACOSCORE, assessing the patient's overall health status and anesthetic risk. - A higher ASA grade (indicating more severe systemic disease) contributes to a higher predicted risk in the THORACOSCORE model.
Question 4: Match the following drugs in Column A with their contraindications in Column B. | Column A | Column B | | :-- | :-- | | 1. Morphine | 1. QT prolongation | | 2. Amiodarone | 2. Thromboembolism | | 3. Vigabatrin | 3. Pregnancy | | 4. Estrogen preparations | 4. Head injury |
- A. A-1, B-3, C-2, D-4
- B. A-4, B-1, C-3, D-2 (Correct Answer)
- C. A-3, B-2, C-4, D-1
- D. A-2, B-4, C-1, D-3
Explanation: ***A-4, B-1, C-3, D-2*** - **Morphine** is contraindicated in **head injury** as it can increase intracranial pressure and mask neurological symptoms. - **Amiodarone** is contraindicated in patients with **QT prolongation** due to its risk of inducing more severe arrhythmias like Torsades de Pointes. - **Vigabatrin** is contraindicated during **pregnancy** due to its potential for teratogenicity and adverse effects on fetal development. - **Estrogen preparations** are contraindicated in patients with a history of **thromboembolism** due to their increased risk of blood clot formation. *A-1, B-3, C-2, D-4* - This option incorrectly matches **Morphine** with QT prolongation and **Estrogen preparations** with head injury, which are not their primary contraindications. - It also incorrectly links **Vigabatrin** with thromboembolism and **Amiodarone** with pregnancy. *A-3, B-2, C-4, D-1* - This choice incorrectly associates **Morphine** with pregnancy and **Vigabatrin** with head injury, which are not the most critical or direct contraindications. - It also misaligns **Amiodarone** with thromboembolism and **Estrogen preparations** with QT prolongation. *A-2, B-4, C-1, D-3* - This option incorrectly matches **Morphine** with thromboembolism and **Amiodarone** with head injury, which are not their most significant contraindications. - It also incorrectly links **Vigabatrin** with QT prolongation and **Estrogen preparations** with pregnancy.
Question 5: Which of the following is not a risk factor for postoperative pulmonary complication?
- A. Normal BMI (18.5-24.9) (Correct Answer)
- B. Age 25-40 years
- C. Upper abdominal surgery
- D. Patient with 20 pack years of smoking
Explanation: ***Patient with 20 pack years of smoking*** - This is a significant risk factor for postoperative pulmonary complications, as **chronic smoking** impairs lung function and mucociliary clearance. - Patients with a history of **20 pack-years or more** are at a substantially increased risk of developing atelectasis, pneumonia, and respiratory failure after surgery. *Normal BMI (18.5-24.9)* - A **normal BMI** is not considered a risk factor for postoperative pulmonary complications; instead, it is associated with a lower risk compared to obesity or underweight states. - Patients with a normal BMI generally have **better respiratory mechanics** and lung volumes, reducing their susceptibility to pulmonary issues. *Age 25-40 years* - This age range is generally associated with a **lower risk** of postoperative pulmonary complications compared to very young or elderly patients. - Younger adults typically have **better physiological reserves** and healthier lungs, contributing to a reduced incidence of respiratory problems post-surgery. *Upper abdominal surgery* - **Upper abdominal surgery** is a significant risk factor for postoperative pulmonary complications due to its proximity to the diaphragm. - It often leads to **diaphragmatic dysfunction**, reduced lung volumes, and increased pain, all of which predispose patients to atelectasis and pneumonia.
Question 6: Preoperative investigations done prior to surgery depend upon which of the following? 1. Type of surgery 2. Patient origin 3. Patient comorbidities 4. Experience of surgeon
- A. 4. Experience of surgeon
- B. 1. Type of surgery (Correct Answer)
- C. 2. Patient origin
- D. 3. Patient comorbidities
Explanation: ***1. Type of surgery*** - The **type of surgery** is a primary determinant of preoperative investigations, as it defines the baseline assessment needed based on the procedure's complexity, invasiveness, and physiological stress. - Minor surgeries (e.g., superficial excisions) typically require minimal investigations, while major surgeries (e.g., cardiac, neurosurgery) mandate comprehensive cardiovascular, pulmonary, and hematological workups. - **Clinical Note:** In practice, preoperative investigations depend on BOTH the surgery type AND patient comorbidities working together, but this question likely seeks the most fundamental starting point. *3. Patient comorbidities* - **Patient comorbidities** are undeniably crucial in determining the extent and nature of preoperative investigations. - A patient with diabetes, hypertension, or cardiac disease requires additional specific investigations regardless of the surgery type. - However, the surgery type establishes the baseline framework, which is then modified based on comorbidities. *2. Patient origin* - **Patient origin** (geographical location, ethnicity) is generally not a direct determinant of preoperative investigation protocols. - While certain populations may have higher prevalence of specific conditions, investigations are based on individual patient assessment, not origin. *4. Experience of surgeon* - The **experience of the surgeon** does not alter the medical necessity or standard protocols for preoperative investigations. - Patient safety standards and investigation requirements remain consistent regardless of surgical expertise level.
Question 7: Postoperative pulmonary complications are seen/expected in all except:
- A. Upper abdominal surgery
- B. Age >70
- C. Patient with 7 pack years of smoking (Correct Answer)
- D. BMI>30
Explanation: ***Patient with 7 pack years of smoking*** - While smoking is a risk factor for pulmonary complications, a history of **7 pack-years** is considered a relatively low cumulative exposure compared to other significant risk factors. - The impact of smoking on postoperative complications is often more pronounced with **higher pack-year histories** or in the presence of existing pulmonary disease. *Upper abdominal surgery* - **Upper abdominal surgery** is associated with a high risk of postoperative pulmonary complications due to proximity to the diaphragm, leading to pain-related **splinting** and **reduced lung volumes**. - This can result in **atelectasis** and pneumonia, as diaphragmatic function is often impaired. *Age >70* - **Advanced age** (over 70 years) is a significant independent risk factor for postoperative pulmonary complications due to age-related physiological changes, including **decreased lung elasticity** and **reduced cough reflex**. - Older patients often have comorbidities that further increase their susceptibility to these complications. *BMI>30* - A **BMI greater than 30** (obesity) significantly increases the risk of postoperative pulmonary complications due to altered respiratory mechanics, including **reduced functional residual capacity** and **increased work of breathing**. - Obese patients also have a higher incidence of **sleep apnea**, which can exacerbate postoperative hypoxia.
Question 8: Thyroid storm during surgery is due to?
- A. Perioperative intervention
- B. Inadequate preoperative preparation (Correct Answer)
- C. Glucocorticoid side effect
- D. Rough handling during surgery
Explanation: ***Inadequate preoperative preparation*** - **Thyroid storm** is a life-threatening exaggeration of hyperthyroidism, often triggered in patients who are **inadequately prepared** for surgery. - This typically means insufficient control of thyroid hormone levels (e.g., with antithyroid drugs, beta-blockers) prior to a surgical stressor. *Perioperative intervention* - While surgery itself is a stressor, a properly performed **perioperative intervention** on a well-prepared patient is less likely to trigger thyroid storm. - The problem is not the intervention itself, but the patient's underlying uncontrolled hyperthyroid state. *Glucocorticoid side effect* - **Glucocorticoids** are often used to treat thyroid storm, not cause it. - They help reduce peripheral conversion of T4 to T3 and provide adrenal support. *Rough handling during surgery* - While **rough handling** during thyroid surgery (e.g., excessive manipulation of the thyroid gland) can, in theory, release some thyroid hormone, it is a less significant factor in triggering thyroid storm than overall systemic hyperthyroidism. - The primary cause remains **inadequate systemic control** of thyroid hormone levels.
Question 9: A patient posted for Lap Cholecystectomy had drug eluting stent placed two years back. Patient has no symptoms since then. Which of the following set of investigation should be done in this patient?
- A. Coronary angiography, Thallium scan
- B. ECG, CBC, Coronary angiography
- C. ECG, CBC, Stress echocardiography (Correct Answer)
- D. ECG, CBC, Stress echocardiography, coronary angiography
Explanation: **ECG, CBC, Stress echocardiography** - A patient with a **drug-eluting stent (DES)** placed two years prior, who is now asymptomatic, typically requires a **non-invasive cardiac assessment** before surgery. [1] - **Stress echocardiography** is an appropriate investigation to assess for inducible ischemia in an asymptomatic patient with a history of DES, especially when determining readiness for non-cardiac surgery. [1] *Coronary angiography, Thallium scan* - **Coronary angiography** is an invasive procedure and is generally not indicated for asymptomatic patients two years post-DES unless there are new symptoms or high-risk findings on non-invasive tests. [2] - A **Thallium scan** (myocardial perfusion scintigraphy) is a valid stress test, but **stress echocardiography** provides similar information regarding ischemia and ventricular function without radiation exposure. [1] *ECG, CBC, Coronary angiography* - While **ECG** and **CBC** are standard preoperative tests, **coronary angiography** is an invasive procedure and is not the first-line investigation for an asymptomatic patient two years post-DES without other indications. [2] - The patient's asymptomatic status suggests that invasive testing is not immediately warranted for surgical clearance. *ECG, CBC, Stress echocardiography, coronary angiography* - Performing both **stress echocardiography** and **coronary angiography** in an asymptomatic patient two years after DES placement is **redundant** and subjects the patient to an unnecessary invasive procedure. [1], [2] - The results of a non-invasive stress test like stress echocardiography would guide the need for any further invasive intervention.
Question 10: Warfarin to be stopped how many days before surgery?
- A. 8 to 9 days
- B. 2 to 3 days
- C. 6 to 7 days
- D. 4 to 5 days (Correct Answer)
Explanation: ***4 to 5 days*** - Warfarin has a **half-life of 36–42 hours**, meaning it takes several days for its anticoagulant effect to wear off. - Stopping warfarin **4-5 days prior to surgery** is generally recommended to allow the **INR (International Normalized Ratio)** to normalize or fall to a safe level (<1.5), minimizing bleeding risk while avoiding prolonged periods without anticoagulation. *8 to 9 days* - This duration is **longer than typically necessary** for warfarin to be sufficiently cleared, potentially increasing the risk of **thromboembolic events** unnecessarily. - Stopping warfarin for this long could lead to a **therapeutic gap** where the patient is vulnerable to clots without adequate anticoagulation, especially for those at high risk. *2 to 3 days* - This period is generally **too short** for warfarin's anticoagulant effects to fully diminish, which could lead to an **elevated INR** and an increased risk of **perioperative bleeding**. - The full effect of warfarin cessation is typically not observed until at least **4 days** due to its half-life and the turnover of vitamin K-dependent clotting factors. *6 to 7 days* - While this duration would ensure a safe INR, it is often **longer than strictly needed** and could unnecessarily prolong the period in which the patient is off anticoagulation. - This extended period increases the risk of **thromboembolic events** for patients who require continuous anticoagulation, without providing significant additional safety benefits over a 4-5 day stop.
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