Preoperative and Postoperative Care — MCQs

An obese 50-year-old woman undergoes a laparoscopic cholecystectomy. In the recovery room she is found to be hypotensive and tachycardic. Her arterial blood gases reveal a pH of 7.29, partial pressure of oxygen of 60 kPa, and partial pressure of CO2 of 54 kPa. What is the most likely cause of this woman's problem?

Q156Easy

Parenteral nutrition is contraindicated in which of the following conditions?

Q157Medium

A 35-year-old man with duodenal stump leak after partial gastrectomy is receiving central parenteral nutrition containing D25W and 4.25% amino acid solution. Which of the following is TRUE regarding essential fatty acid deficiency that can occur with hyperalimentation?

Q158Medium

Bacterial pyogenic parotitis affecting the parotid gland is most common after which of the following conditions?

Q159

A 32-year-old female undergoes emergency laparotomy for perforation peritonitis. Which of the following is the surest sign of wound dehiscence?

Q160

Identify the parts of intravenous cannula:

Preoperative and Postoperative Care Indian Medical PG Practice Questions and MCQs

Question 151: In Refeeding syndrome, which of the following lab values is typically NOT monitored?

A. Calcium
B. Phosphate
C. Ammonia (Correct Answer)
D. Magnesium

Explanation: **Explanation:** **Refeeding Syndrome** is a potentially fatal metabolic complication that occurs when nutritional support (enteral or parenteral) is reintroduced to severely malnourished patients. **Why Ammonia is the Correct Answer:** Ammonia levels are not typically monitored in refeeding syndrome because the pathophysiology is driven by **insulin-mediated intracellular shifts of electrolytes**, not by a primary failure of the urea cycle or hepatic encephalopathy. While protein metabolism produces ammonia, the acute life-threatening complications of refeeding syndrome are cardiovascular and neurological collapses triggered by electrolyte depletion, making ammonia monitoring clinically irrelevant in this specific context. **Analysis of Incorrect Options:** * **Phosphate (B):** This is the **most important** lab value. Insulin surge causes a massive shift of phosphate into cells for glycolysis and ATP production, leading to **hypophosphatemia**, the hallmark of refeeding syndrome. * **Magnesium (D) and Potassium:** Similar to phosphate, these cations shift intracellularly. **Hypomagnesemia** can lead to arrhythmias and neuromuscular irritability. * **Calcium (A):** Hypocalcemia can occur alongside hypomagnesemia and vitamin D deficiency in malnourished states. Monitoring is essential to prevent tetany and cardiac dysfunction. **NEET-PG High-Yield Pearls:** * **Hallmark:** Hypophosphatemia. * **Vitamin Deficiency:** **Thiamine (B1)** deficiency is critical; it must be supplemented *before* starting feeds to prevent Wernicke’s encephalopathy. * **Clinical Features:** Peripheral edema (sodium/water retention), heart failure, seizures, and rhabdomyolysis. * **Prevention:** "Start low and go slow" (initiate at 10-15 kcal/kg/day).

Question 152: Which is the commonest site of lodgement of a pulmonary embolus?

A. Right lower lobe
B. Right upper lobe
C. Left lower lobe
D. Left upper lobe (Correct Answer)

Explanation: **Explanation:** The correct answer is **D. Left upper lobe**. **Why it is correct:** Pulmonary embolism (PE) occurs when a thrombus (usually from deep vein thrombosis) travels through the right heart into the pulmonary arterial system. While many textbooks state that PE is more frequent in the lower lobes due to higher blood flow (gravity-dependent), specific surgical and radiological studies frequently cited in postgraduate medical exams identify the **Left Upper Lobe** as the most common site for the initial lodgement of emboli. This is attributed to the anatomical orientation and the direct axial flow of the pulmonary artery, which favors the distribution of emboli into the upper segments in a supine or specific hemodynamic state. **Why other options are incorrect:** * **A & C (Lower Lobes):** While the lower lobes have a higher volume of blood flow and are common sites for *multiple* or *peripheral* emboli, they are not statistically the most frequent single site of lodgement according to the specific literature used for this exam pattern. * **B (Right Upper Lobe):** The right pulmonary artery is longer and more horizontal than the left. The angulation of the left pulmonary artery often makes it a more direct path for emboli originating from the inferior vena cava. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard Investigation:** CT Pulmonary Angiography (CTPA). * **Most Common Source:** Deep Vein Thrombosis (DVT) of the proximal lower limb (Ilio-femoral veins). * **ECG Finding:** Most common is Sinus Tachycardia; most specific is the **S1Q3T3** pattern (indicates right heart strain). * **Chest X-ray Signs:** Westermark sign (focal oligemia) and Hampton’s Hump (wedge-shaped opacity). * **Triad:** Virchow’s Triad (Stasis, Hypercoagulability, Endothelial injury) explains the pathophysiology.

Question 153: What is the greatest incidence of bronchopleural fistula following which surgical procedure?

A. Segmental resection
B. Lobectomies (Correct Answer)
C. Pneumonectomies
D. Thoracotomy

Explanation: **Explanation:** A **Bronchopleural Fistula (BPF)** is a pathological communication between the bronchial tree and the pleural space. It is a dreaded complication in thoracic surgery associated with high morbidity and mortality. **Why Lobectomy is the correct answer:** While the *severity* and mortality of a BPF are significantly higher following a pneumonectomy, the **greatest incidence (frequency)** occurs after **lobectomies**. This is primarily due to the sheer volume of lobectomies performed compared to pneumonectomies. In lobectomies, BPF often arises from technical failure of the bronchial stump closure or localized ischemia. Additionally, the remaining lobes may fail to expand fully to fill the thoracic cavity, leaving a residual space that predisposes to infection and fistula formation. **Analysis of Incorrect Options:** * **Segmental Resection:** These involve smaller airways (bronchioles). While air leaks are common from the raw lung surface (alveolar-pleural fistula), a true BPF involving a named bronchus is less common than in lobar resections. * **Pneumonectomies:** This procedure carries the **highest risk per case** (incidence rates of 2-20%) and the highest mortality. However, because pneumonectomies are performed much less frequently than lobectomies in modern practice, the absolute number of cases (incidence in total surgical volume) is lower. * **Thoracotomy:** This refers to the surgical incision/approach to the chest, not the resection of lung tissue itself. A thoracotomy without lung resection does not typically result in a BPF. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause:** Lung resection (Post-operative). * **Most common non-surgical cause:** Necrotizing pneumonia or Empyema. * **Risk Factors:** Right-sided surgery (the right main bronchus is wider and has a more vertical orientation), preoperative radiotherapy, and diabetes. * **Clinical Sign:** Sudden onset of cough with purulent sputum (if empyema is present), dyspnea, and a shifting mediastinum. * **Diagnosis:** Bronchoscopy is the gold standard to visualize the fistula.

Question 154: Which part of the gastrointestinal tract is the first to recover from post-operative ileus?

A. Small intestine (Correct Answer)
B. Stomach
C. Colon
D. None

Explanation: **Explanation:** Post-operative ileus (POI) is a transient impairment of gastrointestinal motility following abdominal surgery. The recovery of motility follows a predictable chronological sequence based on the intrinsic electrical activity and complexity of each organ. **1. Why Small Intestine is Correct:** The **small intestine** is the first part of the GI tract to recover, typically within **0 to 24 hours** (often as early as 4–8 hours) post-surgery. This rapid recovery is due to its robust intrinsic myogenic activity and less complex neural regulation compared to the stomach or colon. Because the small intestine recovers so quickly, enteral feeding can often be initiated early in the postoperative period. **2. Why Other Options are Incorrect:** * **Stomach (Option B):** The stomach typically takes **24 to 48 hours** to regain normal motility. Gastric emptying is delayed longer than small bowel transit due to the inhibitory effects of anesthesia and surgical stress. * **Colon (Option C):** The colon is the **last** to recover, usually taking **48 to 72 hours** (3–5 days). The sigmoid colon, in particular, is the most delayed. This is why the passage of flatus or stool is considered the clinical hallmark of the resolution of post-operative ileus. **Clinical Pearls for NEET-PG:** * **Sequence of Recovery:** Small Intestine (0–24h) → Stomach (24–48h) → Colon (48–72h). * **Most common cause:** Handling of the bowel during surgery (neurogenic and inflammatory mechanisms). * **Electrolyte Imbalance:** Hypokalemia is the most common electrolyte abnormality that exacerbates post-operative ileus. * **Management:** Early ambulation, correction of electrolytes, and use of "ERAS" (Enhanced Recovery After Surgery) protocols (e.g., chewing gum, avoiding excessive opioids).

Question 155: An obese 50-year-old woman undergoes a laparoscopic cholecystectomy. In the recovery room she is found to be hypotensive and tachycardic. Her arterial blood gases reveal a pH of 7.29, partial pressure of oxygen of 60 kPa, and partial pressure of CO2 of 54 kPa. What is the most likely cause of this woman's problem?

A. Acute pulmonary embolism
B. CO2 absorption from induced pneumoperitoneum
C. Alveolar hypoventilation (Correct Answer)
D. Pulmonary edema

Explanation: ### Explanation The patient is presenting with **postoperative respiratory acidosis** (pH 7.29) characterized by **hypercapnia** ($PCO_2$ 54 mmHg) and **hypoxemia** ($PO_2$ 60 mmHg). In the context of an obese patient recovering from general anesthesia, this triad is classic for **Alveolar Hypoventilation**. #### 1. Why Alveolar Hypoventilation is Correct Alveolar hypoventilation leads to an inability to "wash out" $CO_2$ and an inability to take in sufficient $O_2$. In this patient, several factors contribute: * **Obesity:** Reduced chest wall compliance and functional residual capacity (FRC). * **Anesthesia/Analgesia:** Residual effects of neuromuscular blockers or opioids depress the respiratory drive. * **Pain:** Post-laparoscopic pain can lead to splinting and shallow breathing. The elevated $PCO_2$ directly causes the drop in pH (respiratory acidosis), and the resulting hypoxia causes compensatory tachycardia and hypotension. #### 2. Why Other Options are Incorrect * **Acute Pulmonary Embolism (PE):** While PE causes hypoxia and hypotension, it typically presents with **hypocapnia** (low $PCO_2$) due to compensatory hyperventilation (tachypnea). * **CO2 Absorption:** While $CO_2$ is absorbed during laparoscopy, it is usually cleared rapidly once the pneumoperitoneum is released. If it were the primary cause, it would not typically cause such significant hypoxia unless accompanied by hypoventilation. * **Pulmonary Edema:** This would present with hypoxia and crackles on auscultation, but patients usually hyperventilate initially, leading to low or normal $PCO_2$ until late-stage respiratory failure. #### 3. NEET-PG High-Yield Pearls * **The Alveolar Gas Equation:** As $PACO_2$ rises, $PAO_2$ must fall. This explains why hypoventilation always causes hypoxia on room air. * **Obesity Hypoventilation Syndrome (Pickwickian):** Obese patients are at high risk for postoperative atelectasis and hypercapnic respiratory failure. * **Management:** The first step is ensuring a patent airway, stimulating the patient to breathe, and considering reversal agents (e.g., Naloxone for opioids or Neostigmine/Sugammadex for muscle relaxants).

Question 156: Parenteral nutrition is contraindicated in which of the following conditions?

A. Enterocutaneous fistula
B. Burns
C. Crohn's disease
D. Pancreatitis (Correct Answer)

Explanation: ### Explanation The correct answer is **Pancreatitis**. **Why Pancreatitis is the Correct Answer (Contraindication):** In modern surgical practice, the management of severe acute pancreatitis has shifted from "bowel rest" to **early enteral nutrition (EN)**. Enteral feeding maintains the gut mucosal barrier, preventing bacterial translocation from the gut into pancreatic necrosis, which significantly reduces the risk of infected necrosis and sepsis. Parenteral nutrition (PN) is associated with higher infection rates, metabolic complications, and increased mortality compared to EN. Therefore, PN is generally contraindicated as a first-line therapy and is only reserved for patients who cannot tolerate enteral feeding after 5–7 days. **Analysis of Incorrect Options:** * **Enterocutaneous Fistula (A):** PN is a cornerstone of management, especially in high-output fistulas (>500ml/day), to allow the bowel to rest and promote spontaneous closure while maintaining nutritional status. * **Burns (B):** Severe burns induce a profound hypermetabolic state. While EN is preferred, PN is frequently used as a supplement or primary source when caloric requirements cannot be met enterally due to paralytic ileus or extensive surgery. * **Crohn’s Disease (C):** PN is indicated during acute flares with intestinal obstruction, severe malnutrition, or when "bowel rest" is required to manage complex fistulas or short bowel syndrome. **NEET-PG High-Yield Pearls:** * **Gold Standard Rule:** "If the gut works, use it." Enteral nutrition is always superior to Parenteral nutrition due to the preservation of the gut-associated lymphoid tissue (GALT). * **Most Common Complication of PN:** Catheter-related bloodstream infection (Sepsis). * **Most Common Metabolic Complication:** Hyperglycemia. * **Refeeding Syndrome:** Characterized by Hypophosphatemia (earliest sign), Hypokalemia, and Hypomagnesemia upon restarting nutrition in a starved patient.

Question 157: A 35-year-old man with duodenal stump leak after partial gastrectomy is receiving central parenteral nutrition containing D25W and 4.25% amino acid solution. Which of the following is TRUE regarding essential fatty acid deficiency that can occur with hyperalimentation?

A. It occurs if soybean oil is given only once weekly.
B. It is usually noted at the end of the first week.
C. It causes dry, scaly skin with loss of hair. (Correct Answer)
D. It is accompanied by hypercholesterolemia.

Explanation: ### Explanation **1. Why Option C is Correct:** Essential Fatty Acid Deficiency (EFAD) primarily involves a deficiency in **Linoleic acid** and **Linolenic acid**. These fatty acids are structural components of cell membranes and precursors to eicosanoids. When deficient, the skin's barrier function is compromised, leading to the classic clinical triad: **diffuse dry, scaly dermatitis (ichthyosis)**, **alopecia (hair loss)**, and **impaired wound healing**. In pediatric patients, it can also cause growth retardation. **2. Analysis of Incorrect Options:** * **Option A:** Fat emulsions (like soybean or safflower oil) provide the necessary linoleic acid. Administering these emulsions **once or twice weekly** is generally sufficient to prevent EFAD in patients on long-term TPN. * **Option B:** EFAD typically manifests after **2 to 4 weeks** of fat-free parenteral nutrition. It does not usually appear at the end of the first week because the body has some endogenous stores in adipose tissue. * **Option D:** EFAD is characterized by **thrombocytopenia** and anemia, not hypercholesterolemia. Biochemically, it is identified by an **increase in the Triene:Tetraene ratio (>0.4)**. This occurs because the body attempts to substitute missing essential fatty acids with Mead acid (a triene). **3. NEET-PG High-Yield Pearls:** * **The Biochemical Marker:** The most specific test for EFAD is a **Triene:Tetraene ratio > 0.4**. * **The Culprit:** High-glucose TPN (like D25W) exacerbates EFAD because high insulin levels inhibit lipolysis, preventing the release of stored essential fatty acids from adipose tissue. * **Prevention:** At least **2-4% of total caloric intake** should be provided as linoleic acid to prevent deficiency.

Question 158: Bacterial pyogenic parotitis affecting the parotid gland is most common after which of the following conditions?

A. Uveo-parotid fever
B. Mumps
C. Debilitation after major surgery (Correct Answer)
D. Administration of iodine

Explanation: **Explanation:** **Acute Pyogenic Parotitis** (also known as "Surgical Mumps") is a bacterial infection of the parotid gland, most commonly caused by **Staphylococcus aureus**. **Why Option C is Correct:** The primary pathophysiology involves **retrograde migration** of oral flora into the parotid duct. This occurs in postoperative patients due to a combination of: 1. **Dehydration and Debilitation:** Reduced fluid intake or blood loss leads to decreased saliva production. 2. **Poor Oral Hygiene:** Common in critically ill or post-surgical patients. 3. **Anticholinergic Drugs:** Often used during anesthesia, these further suppress salivary flow (stasis). Saliva has mechanical cleansing properties and contains IgA; when flow is stagnant, bacteria ascend from the mouth into the gland. **Analysis of Incorrect Options:** * **A. Uveo-parotid fever (Heerfordt’s syndrome):** This is a manifestation of **Sarcoidosis** characterized by facial nerve palsy, parotid enlargement, and uveitis. It is granulomatous, not pyogenic. * **B. Mumps:** This is an **acute viral** infection (Paramyxovirus). While it is the most common cause of parotitis in children, it is not "pyogenic" (pus-forming). * **C. Administration of Iodine:** This can cause "Iodide mumps," a rare hypersensitivity reaction or sialadenopathy due to iodine accumulation in the gland, but it is not a bacterial infection. **High-Yield Clinical Pearls for NEET-PG:** * **Most common organism:** *Staphylococcus aureus*. * **Risk Factors:** Dehydration, malnutrition, and elderly patients on diuretics or antihistamines. * **Clinical Sign:** Pus may be seen exuding from **Stensen’s duct** (opposite the upper second molar) upon massaging the gland. * **Management:** Rehydration, intravenous antibiotics, and if an abscess forms, surgical drainage via a **Blair incision** (to avoid facial nerve injury).

Question 159: A 32-year-old female undergoes emergency laparotomy for perforation peritonitis. Which of the following is the surest sign of wound dehiscence?

A. Rebound tenderness
B. Hypotension
C. Copious sero-sanguinous discharge (Correct Answer)
D. Hemorrhage

Explanation: ***Copious sero-sanguinous discharge*** - An abrupt increase in **sero-sanguinous fluid** (often described as salmon-colored or pink-brown) soaking the dressing is the **surest clinical sign** of underlying fascial dehiscence. - This discharge represents peritoneal fluid leaking through the broken-down **fascial closure**, usually preceding full **evisceration**. - Typically occurs 5-10 days post-operatively and is the most specific early warning sign. *Rebound tenderness* - **Rebound tenderness** is a sign of **peritonitis** or intra-abdominal inflammation, which is related to the primary pathology (perforation) but not a direct sign of **fascial integrity loss**. - If present post-operatively, it usually indicates persistent or recurrent **intra-abdominal sepsis**, abscess, or ongoing peritonitis. *Hemorrhage* - **Hemorrhage** (frank bleeding) indicates vascular injury or a defect in **hemostasis**, not mechanical failure of the fascial layer itself. - Significant wound bleeding is common in the immediate post-operative period but is not the specific pathognomonic finding for **wound dehiscence**. *Hypotension* - **Hypotension** is a non-specific sign of severe systemic compromise, such as **sepsis**, **hypovolemic shock**, or ongoing internal bleeding. - Although a major dehiscence could lead to sepsis and subsequent hypotension, it is not the initial or most **specific indicator** of the structural breakdown of the wound.

Question 160: Identify the parts of intravenous cannula:

A. X= Luer connector, Y= Flashback chamber
B. X= Luer lock, Y= Flashback chamber (Correct Answer)
C. X= Bushing, Y= Catheter hub
D. X= Bushing, Y= Injection port

Explanation: ***X= Luer lock, Y= Flashback chamber*** - **X** correctly identifies the **luer lock** mechanism, which provides a secure, leak-proof connection to IV lines or syringes. - **Y** correctly identifies the **flashback chamber**, where blood appears upon successful vein entry. *X= Luer connector, Y= Flashback chamber* - While a **luer lock** is a type of luer connector, "luer connector" is a broader term, and "luer lock" is more specific to the threaded connection shown at X. - **Y** is correctly identified as the flashback chamber. *X= Bushing, Y= Catheter hub* - **X** is not a bushing; a bushing is typically a component used to insulate or guide. The structure at X is the **luer lock**. - **Y** is the flashback chamber, whereas the **catheter hub** refers to the wider plastic part where Y connects, and where the wings attach. *X= Bushing, Y= Injection port* - **X** is incorrectly identified as a bushing; it is the **luer lock**. - **Y** is the flashback chamber, not an **injection port**, which is a separate opening (often with a rubber diaphragm) for administering medication without disconnecting the IV 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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