Preoperative and Postoperative Care — MCQs

Preoperative and Postoperative Care Indian Medical PG Practice Questions and MCQs

Question 121: In parenteral alimentation for a patient with Crohn's disease, what is the optimal ratio of calories from carbohydrates per gram of nitrogen?

A. 1 kcal/g nitrogen
B. 5 kcal/g nitrogen
C. 10 kcal/g nitrogen
D. 100 kcal/g nitrogen (Correct Answer)

Explanation: ### Explanation The goal of Total Parenteral Nutrition (TPN) is to achieve a **positive nitrogen balance**, which is essential for tissue repair and protein synthesis, especially in inflammatory conditions like Crohn’s disease. **1. Why Option D is Correct:** In healthy individuals, the body requires a specific amount of non-protein calories (carbohydrates and lipids) to "spare" amino acids from being burned for energy. For patients in a **hypermetabolic or stressed state** (like Crohn’s disease), the optimal **Non-Protein Calorie to Nitrogen (NPC:N) ratio** typically ranges from **100:1 to 150:1**. * Providing **100 kcal of carbohydrates per gram of nitrogen** ensures that the administered amino acids are utilized for protein synthesis (anabolism) rather than being deaminated for energy production. **2. Why Other Options are Incorrect:** * **Options A, B, and C (1, 5, 10 kcal/g):** These ratios are physiologically insufficient. If the calorie-to-nitrogen ratio is too low, the body will oxidize the expensive intravenous amino acids to meet basic energy requirements. This leads to an increase in blood urea nitrogen (BUN) and fails to promote wound healing or weight gain. **3. High-Yield Clinical Pearls for NEET-PG:** * **Standard NPC:N Ratios:** * Normal/Stable patients: **150:1** * Critically ill/Sepsis/Stress: **100:1** (Lower ratio because nitrogen requirements increase more than calorie requirements). * **Nitrogen Content:** 6.25 grams of protein contains approximately 1 gram of nitrogen. * **Crohn’s Disease:** TPN is indicated in Crohn’s for "bowel rest" during severe flares, management of enterocutaneous fistulas, or short-bowel syndrome. * **Monitoring:** The most common metabolic complication of TPN is **hyperglycemia**; the most common electrolyte abnormality is **hypophosphatemia** (part of Refeeding Syndrome).

Question 122: In a patient receiving total parenteral nutrition, what is monitored daily?

A. Body weight (Correct Answer)
B. Plasma protein
C. Plasma osmolality
D. Coagulation profile

Explanation: **Explanation:** Monitoring a patient on Total Parenteral Nutrition (TPN) is critical to prevent metabolic and fluid-related complications. **Why Body Weight is the Correct Answer:** Daily monitoring of **body weight** is the most sensitive and practical indicator of a patient's **fluid status** and the efficacy of nutritional support. In the initial phase of TPN, rapid weight gain (>0.5 kg/day) usually indicates fluid retention or "refeeding syndrome" rather than true tissue accretion. Once stable, weight gain should ideally be 0.2–0.5 kg/day. Along with weight, intake-output charts and serum electrolytes are also monitored daily during the initiation phase. **Analysis of Incorrect Options:** * **B. Plasma Protein:** Albumin and pre-albumin have long half-lives (20 days and 2 days, respectively). They reflect long-term nutritional status and are typically monitored **weekly**, not daily. * **C. Plasma Osmolality:** While TPN is hypertonic, serum osmolality is not routinely measured daily unless the patient develops severe hyperglycemia or hypernatremia. * **D. Coagulation Profile:** Prothrombin time (PT/INR) is generally monitored **weekly** to assess liver function and Vitamin K status, unless the patient has an underlying coagulopathy. **NEET-PG High-Yield Pearls:** * **Most common complication of TPN:** Catheter-related sepsis (usually *Staphylococcus aureus* or *Candida*). * **Most common metabolic complication:** Hyperglycemia. * **Refeeding Syndrome:** Characterized by profound **Hypophosphatemia**, hypokalemia, and hypomagnesemia upon restarting nutrition in a starved patient. * **Liver changes:** Long-term TPN can lead to steatosis (fatty liver) and cholestasis.

Question 123: What is true about reactionary hemorrhage following surgery?

A. Hemorrhage occurring within 48 hours
B. Hemorrhage occurring within 36 hours
C. Hemorrhage occurring within 24 hours (Correct Answer)
D. Hemorrhage occurring during surgery

Explanation: ### Explanation In surgical practice, postoperative hemorrhage is classified based on the timing and etiology of the bleed. **Why Option C is Correct:** **Reactionary hemorrhage** is defined as bleeding that occurs within **24 hours** of surgery (typically between 4–6 hours). It is caused by the **rise in blood pressure** to normal levels as the patient recovers from the effects of anesthesia and surgical shock. This increase in pressure can dislodge "slipping ligatures" or wash out soft clots from vessels that were not bleeding during the hypotensive state of surgery. **Analysis of Incorrect Options:** * **Option A & B (48/36 hours):** These timeframes are incorrect. While bleeding can occur during this window, it does not fit the specific clinical definition of "reactionary." * **Option D (During surgery):** Bleeding that occurs during the procedure is termed **Primary Hemorrhage**. It is usually due to direct vessel injury or inadequate intraoperative hemostasis. **High-Yield NEET-PG Pearls:** 1. **Primary Hemorrhage:** Occurs at the time of operation. 2. **Reactionary Hemorrhage (within 24 hours):** Key triggers include recovery from anesthesia, coughing, vomiting, or aggressive fluid resuscitation (raising BP). 3. **Secondary Hemorrhage (7–14 days):** This occurs late and is almost always due to **infection** eroding a vessel wall. 4. **Management:** For reactionary hemorrhage, the patient often needs to be taken back to the operating theater (re-exploration) to identify and ligated the bleeding vessel.

Question 124: The likely metabolic complications of total parenteral nutrition within the first two weeks of therapy would include all of the following EXCEPT?

A. Cardiopulmonary failure (Correct Answer)
B. Hyperosmolar non-ketotic hyperglycemia
C. Zinc deficiency
D. Hypophosphatemia

Explanation: **Explanation:** The question asks for the complication **least likely** to be classified as a primary metabolic complication of Total Parenteral Nutrition (TPN) within the first two weeks. **1. Why Cardiopulmonary Failure is the Correct Answer:** While fluid overload during TPN can lead to heart failure, **Cardiopulmonary failure** is primarily a clinical syndrome or a systemic consequence rather than a direct "metabolic complication." In the context of TPN, it is usually a secondary result of the **Refeeding Syndrome**, which is characterized by severe electrolyte shifts (like hypophosphatemia). Therefore, it is categorized as a systemic clinical outcome rather than a metabolic derangement itself. **2. Analysis of Incorrect Options (Metabolic Complications):** * **Hyperosmolar non-ketotic hyperglycemia:** This is a common early metabolic complication caused by the high glucose infusion rate in TPN, exceeding the body's insulin capacity. * **Hypophosphatemia:** This is the hallmark of **Refeeding Syndrome**. When glucose is introduced, insulin release shifts phosphate into cells for ATP production, leading to dangerously low serum levels within the first few days. * **Zinc deficiency:** Trace element deficiencies are well-documented metabolic complications of TPN. While some deficiencies take months, zinc levels can drop relatively quickly, especially in patients with high GI output (e.g., fistulas or diarrhea). **High-Yield Clinical Pearls for NEET-PG:** * **Refeeding Syndrome:** Occurs in malnourished patients. Key features: **Hypophosphatemia (most common)**, hypomagnesemia, and hypokalemia. * **Most common TPN complication:** Catheter-related sepsis (Infectious). * **Most common metabolic complication:** Hyperglycemia. * **Long-term TPN complication:** Hepatobiliary dysfunction (steatosis, cholestasis, and gallstones). * **Monitoring:** Check electrolytes and blood glucose daily during the first week of TPN initiation.

Question 125: Which vein is considered the best for initiating total parenteral nutrition?

A. Subclavian vein (Correct Answer)
B. Femoral vein
C. Brachial vein
D. Saphenous vein

Explanation: **Explanation:** Total Parenteral Nutrition (TPN) is a hyperosmolar solution (often >1500 mOsm/L) containing high concentrations of glucose and amino acids. If administered through small peripheral veins, it causes rapid chemical phlebitis and sclerosis. Therefore, TPN must be delivered into a high-flow, large-diameter central vein where rapid hemodilution occurs. **Why the Subclavian Vein is the Correct Answer:** The **subclavian vein** is the preferred site for long-term central venous access and TPN. Its anatomical fixation to the clavicle and first rib ensures it remains patent even in hypovolemic states. Clinically, it is favored because it has the **lowest risk of catheter-related bloodstream infections (CRBSI)** compared to other central sites and offers the greatest patient comfort and ease of dressing maintenance. **Analysis of Incorrect Options:** * **Femoral Vein:** While large, it carries the **highest risk of infection** and thromboembolic complications. It also limits patient mobility. * **Brachial Vein:** This is a peripheral vein. While used for PICC lines (Peripherally Inserted Central Catheters), the vein itself cannot tolerate TPN osmolarity unless the catheter tip is advanced into the Superior Vena Cava. * **Saphenous Vein:** This is a peripheral vein in the lower limb with low flow rates, making it unsuitable for hypertonic TPN solutions. **High-Yield Clinical Pearls for NEET-PG:** * **Ideal Tip Position:** The tip of the TPN catheter should lie in the **Superior Vena Cava (SVC)**. * **Most Common Complication:** The most common metabolic complication of TPN is **Hyperglycemia**; the most common life-threatening electrolyte abnormality is **Hypophosphatemia** (as part of Reeding Syndrome). * **Infection Control:** If a patient on TPN develops an unexplained fever, the TPN line must be considered the primary source until proven otherwise.

Question 126: Which is the best vein for initiating total parenteral nutrition?

A. Subclavian vein (Correct Answer)
B. Femoral vein
C. Brachial vein
D. Saphenous vein

Explanation: **Explanation:** Total Parenteral Nutrition (TPN) is a hyperosmolar solution (often >900 mOsm/L) containing high concentrations of glucose, amino acids, and lipids. To prevent **thrombophlebitis** and ensure rapid dilution of these irritating solutes, TPN must be infused into a large-diameter vein with high blood flow. **Why the Subclavian Vein is the Correct Choice:** The **subclavian vein** is the preferred route for central venous access in TPN because: 1. **High Flow Rate:** It provides rapid dilution of hypertonic solutions, protecting the vessel wall. 2. **Anatomic Stability:** The vein is held patent by its attachments to the clavicle and first rib, making cannulation predictable. 3. **Patient Comfort:** It allows for easier dressing maintenance and greater neck/limb mobility compared to other sites. 4. **Lower Infection Risk:** It has a lower rate of catheter-related bloodstream infections (CRBSI) compared to the femoral or internal jugular routes. **Analysis of Incorrect Options:** * **Femoral Vein:** Associated with the highest risk of **thrombosis and infection** due to its proximity to the groin and difficulty in maintaining a sterile dressing. * **Brachial Vein:** Too small for standard TPN; hyperosmolar solutions would cause immediate chemical phlebitis. (Note: While PICC lines can be inserted here, the tip must still reach the SVC). * **Saphenous Vein:** A peripheral vein in the lower limb with low flow rates; it carries an unacceptably high risk of thrombophlebitis and varicosities. **High-Yield Clinical Pearls for NEET-PG:** * **Ideal Tip Location:** The tip of the TPN catheter should lie in the **Superior Vena Cava (SVC)**. * **Most Common Complication:** The most common metabolic complication of TPN is **Hyperglycemia**; the most common life-threatening electrolyte abnormality is **Hypophosphatemia** (part of Re-feeding Syndrome). * **Infection Control:** If a patient on TPN develops a fever without an obvious source, the TPN catheter is the presumed source until proven otherwise.

Question 127: All of the following are causes of postoperative wound dehiscence except?

A. Malignancy
B. Vitamin B complex deficiency (Correct Answer)
C. Hypoproteinaemia
D. Jaundice

Explanation: **Explanation:** Postoperative wound dehiscence (burst abdomen) is a serious surgical complication usually occurring 5–8 days post-surgery. It is multifactorial, involving patient-related (systemic) and technical (local) factors. **Why Vitamin B complex deficiency is the correct answer:** While Vitamin B complex is essential for general metabolism, it does not play a direct role in collagen synthesis or wound tensile strength. In contrast, **Vitamin C (Ascorbic acid)** is the critical vitamin for wound healing, as it is a mandatory cofactor for the hydroxylation of proline and lysine residues during collagen synthesis. Therefore, Vitamin B deficiency is not a recognized cause of dehiscence. **Analysis of Incorrect Options:** * **Malignancy:** Cancer induces a catabolic state and is often associated with cachexia and poor tissue perfusion, significantly impairing the body’s inflammatory and proliferative responses. * **Hypoproteinaemia:** Albumin is essential for wound healing. Low protein levels (especially <3 g/dL) lead to prolonged inflammatory phases and decreased collagen production, weakening the incision line. * **Jaundice:** Obstructive jaundice is a well-known risk factor. High bilirubin levels and associated bile salt deficiencies impair fibroblast proliferation and collagen cross-linking, leading to poor wound strength. **NEET-PG High-Yield Pearls:** * **Most common cause:** Technical error (improper suturing/tension). * **Most common systemic cause:** Anemia and malnutrition. * **Clinical Sign:** The "Pink Toothbrush" sign—a serosanguinous (pinkish) discharge from the wound is the earliest clinical predictor of impending dehiscence. * **Management:** Immediate coverage with sterile saline-soaked gauze followed by urgent re-exploration and secondary closure (tension-free).

Question 128: Complications of total thyroidectomy are all, EXCEPT:

A. Hypocalcaemia
B. Hypercalcaemia (Correct Answer)
C. Hoarseness of voice
D. Parathyroid loss

Explanation: **Explanation:** The correct answer is **B. Hypercalcaemia**. Total thyroidectomy is a procedure where the entire thyroid gland is removed, often putting adjacent structures at risk. **Why Hypercalcaemia is the exception:** Post-thyroidectomy, the most common metabolic complication is **hypocalcaemia**, not hypercalcaemia. This occurs due to the accidental removal, devascularization, or thermal injury of the parathyroid glands during surgery. Since the parathyroid glands regulate calcium levels via Parathyroid Hormone (PTH), their impairment leads to a drop in serum calcium. **Analysis of other options:** * **Hypocalcaemia (A) & Parathyroid loss (D):** These are closely linked. The parathyroid glands (usually four) lie on the posterior aspect of the thyroid capsule. Even in expert hands, **parathyroid loss** or ischemia is a recognized complication, leading to transient or permanent **hypocalcaemia**. * **Hoarseness of voice (C):** This occurs due to injury to the **Recurrent Laryngeal Nerve (RLN)**, which runs in the tracheoesophageal groove. Unilateral injury causes hoarseness, while bilateral injury can lead to acute airway obstruction (stridor). **NEET-PG High-Yield Pearls:** 1. **Most common complication overall:** Postoperative hypocalcaemia (transient in ~20%, permanent in <1-2%). 2. **Most common nerve injured:** External branch of the Superior Laryngeal Nerve (leads to loss of high-pitched voice/easy vocal fatigue). 3. **Most dreaded complication:** Postoperative hemorrhage causing airway compression (requires immediate bedside hematoma evacuation). 4. **Chvostek’s and Trousseau’s signs:** Clinical indicators of latent tetany due to post-surgical hypocalcaemia.

Question 129: Which of the following is NOT a standard practice performed before surgery?

A. Shaving the surgical site
B. Draping the patient
C. Control of blood glucose levels
D. Initiation of anticoagulation (Correct Answer)

Explanation: **Explanation:** The goal of preoperative care is to optimize the patient’s physiological state and minimize the risk of complications [1]. **Why Option D is correct:** **Initiation of anticoagulation** is generally contraindicated immediately before surgery. Anticoagulants (like Warfarin or Heparin) increase the risk of intraoperative and postoperative hemorrhage [3]. In fact, standard practice involves **discontinuing** anticoagulants (e.g., stopping Warfarin 5 days prior) or "bridging" with short-acting agents like LMWH, which are also timed to wear off before the incision. **Why the other options are incorrect:** * **A. Shaving the surgical site:** While routine "shaving" with a razor is now discouraged due to micro-abrasions that increase Surgical Site Infection (SSI) risk, hair removal using **electric clippers** immediately before surgery is still a standard practice if hair interferes with the procedure. * **B. Draping the patient:** This is a fundamental step in maintaining a sterile field. Draping occurs after skin antisepsis to prevent the transfer of microorganisms from non-sterile areas to the surgical wound. * **C. Control of blood glucose:** Hyperglycemia impairs wound healing and increases SSI risk [4]. Maintaining perioperative glucose (typically <180 mg/dL) is a critical standard of care [2]. **High-Yield Clinical Pearls for NEET-PG:** * **Hair Removal:** If necessary, use clippers; **never** use a razor the night before surgery (increases SSI risk). * **Prophylactic Antibiotics:** Should be administered within **60 minutes before** the skin incision [4]. * **Smoking Cessation:** Ideally, patients should stop smoking at least **4 weeks** before surgery to reduce pulmonary complications and improve wound healing. * **DVT Prophylaxis:** While *anticoagulation* is not "initiated" as a standard for all, **thromboprophylaxis** (mechanical or pharmacological) is assessed based on Caprini scores.

Question 130: All of the following are complications of TPN except?

A. Volume overload
B. Hypokalemia
C. Metabolic acidosis
D. Hypochloremia (Correct Answer)

Explanation: **Explanation:** Total Parenteral Nutrition (PN) is a complex intravenous therapy that bypasses the gastrointestinal tract, frequently leading to metabolic and electrolyte imbalances. **Why Hypochloremia is the correct answer:** TPN is more commonly associated with **Hyperchloremia**, not hypochloremia. This occurs because many amino acids in TPN solutions are provided as chloride salts (e.g., Lysine hydrochloride). An excess of these chloride ions can lead to **Hyperchloremic Metabolic Acidosis**. Therefore, hypochloremia is not a standard complication of TPN. **Analysis of Incorrect Options:** * **Volume Overload:** TPN solutions are highly osmolar and require significant fluid volume for administration. In patients with compromised cardiac or renal function, this can easily lead to fluid overload and pulmonary edema. * **Hypokalemia:** This is a classic feature of **Refeeding Syndrome**. When glucose is infused, insulin is released, shifting potassium, magnesium, and phosphate from the extracellular to the intracellular compartment, resulting in low serum levels. * **Metabolic Acidosis:** As mentioned, the use of crystalline amino acid solutions (hydrochloride salts) and the metabolism of certain lipids can increase the acid load, leading to metabolic acidosis. **High-Yield Clinical Pearls for NEET-PG:** * **Most common metabolic complication:** Hyperglycemia. * **Refeeding Syndrome triad:** Hypophosphatemia (most characteristic), Hypokalemia, and Hypomagnesemia. * **Hepatobiliary complication:** Cholestasis and cholelithiasis (due to lack of enteral stimulation and CCK release). * **Most common infection:** Coagulase-negative Staphylococci (*S. epidermidis*) via the central line.

Practice by Chapter

Preoperative Risk Assessment

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Perioperative Management of Comorbidities

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Preparation of Patient for Surgery

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Informed Consent Process

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Post-Anesthesia Care

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Pain Management

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Wound Care and Dressings

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Drain Management

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Postoperative Complications Detection

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Early Ambulation and Rehabilitation

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Enhanced Recovery After Surgery (ERAS) Protocols

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Discharge Planning and Follow-up

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