Preoperative and Postoperative Care Practice Questions

Q: Following splenectomy in children, which one of the following is recommended?

Pneumococcal vaccination. **Explanation:** The spleen plays a critical role in the immune system by filtering blood-borne pathogens and producing opsonins (like tuftsin and properdin). Post-splenectomy, patients are at a lifelong risk of **Overwhelming Post-Splenectomy Infection (OPSI)**, primarily caused by **encapsulated organisms**. **Why Pneumococcal Vaccination is Correct:** *Streptococcus pneumoniae* is the most common cause of OPSI, accounting for 50–90% of cases. Therefore, immunization against Pneumococcus is mandatory. Ideally, vaccines should be administered **at least 2 weeks before** elective splenectomy or **2 weeks after** emergency surgery to ensure an adequate immune response. **Analysis of Incorrect Options:** * **Hepatitis B & Typhoid Vaccination:** While important in general pediatric schedules, these are not specifically mandated by the loss of splenic function. The spleen is not the primary site for clearing these specific pathogens. * **Regular Follow-up:** While follow-up is necessary for monitoring, it is a general management step and does not provide the specific immunological protection required to prevent life-threatening sepsis. **High-Yield Clinical Pearls for NEET-PG:** 1. **The "Big Three" Vaccines:** Post-splenectomy patients must receive vaccines against *Streptococcus pneumoniae*, *Haemophilus influenzae* type b (Hib), and *Neisseria meningitidis*. 2. **Antibiotic Prophylaxis:** Daily oral **Penicillin V** prophylaxis is recommended, especially in children under 5 years of age or for at least 2 years post-surgery. 3. **Timing:** If the surgery is elective, vaccinate 14 days prior. If emergency, vaccinate 14 days post-op (to avoid the period of post-surgical "immunological stun"). 4. **Annual Flu Shot:** Recommended to prevent secondary bacterial pneumonia.

Q: When should antibiotics be given for surgical prophylaxis?

1 hour before surgery. The goal of surgical antimicrobial prophylaxis (SAP) is to ensure that the **peak serum and tissue concentrations** of the antibiotic exceed the minimum inhibitory concentration (MIC) for the likely pathogens at the exact moment of **skin incision**. ### Why Option A is Correct Administering antibiotics **within 60 minutes before the surgical incision** (ideally at the time of anesthesia induction) allows for optimal tissue distribution. For most commonly used antibiotics (like Cefazolin), this window ensures maximum bactericidal activity during the period of highest contamination risk—the incision and initial dissection. *Note: For antibiotics with longer infusion times or half-lives, such as Vancomycin or Fluoroquinolones, administration should begin within 120 minutes before incision.* ### Why Other Options are Incorrect * **Option B & D (Post-surgery):** Administering antibiotics after the incision has been made or the surgery has ended is ineffective for prophylaxis. By this time, bacteria may have already contaminated the surgical site and established a nidus of infection. * **Option C (2 hours before):** For standard beta-lactams, giving the dose too early (beyond 60 minutes) may result in serum levels falling below the MIC by the time the surgery reaches its critical stages or if the procedure is prolonged. ### NEET-PG High-Yield Pearls 1. **Timing:** The single most important factor in SAP is the timing relative to the incision. 2. **Redosing:** Antibiotics should be redosed if the surgery exceeds two half-lives of the drug or if there is significant blood loss (>1500 mL). 3. **Duration:** In most clean and clean-contaminated cases, a **single preoperative dose** is sufficient. Prophylaxis should generally not exceed 24 hours postoperatively. 4. **Choice of Drug:** First-generation cephalosporins (e.g., Cefazolin) are the gold standard for most procedures due to their coverage against *Staphylococcus aureus*.

Q: A 42-year-old man has had a rocky course for the 3 days following a bowel resection for intestinal perforation due to inflammatory bowel disease. His central venous pressure (CVP) had been 12 to 14 but is now 6, in the face of diminished blood pressure and oliguria. Which of the following is the most likely etiology of his hypotension?

Gram-negative sepsis. **Explanation:** The clinical scenario describes a patient 3 days post-bowel resection for perforation (a high-risk setting for contamination) presenting with a sudden drop in Central Venous Pressure (CVP), hypotension, and oliguria. **1. Why Gram-negative Sepsis is Correct:** In the early stages of **septic shock** (distributive shock), there is massive peripheral vasodilation and an increase in capillary permeability. This leads to "relative hypovolemia" as fluid leaks into the interstitial space (third-spacing). The hallmark is a **decrease in CVP** (due to decreased venous return) accompanied by hypotension. Given the history of intestinal perforation and bowel surgery, Gram-negative bacteria (like *E. coli* or *Bacteroides*) are the most likely culprits. **2. Why the Other Options are Incorrect:** * **Pulmonary Embolism (PE):** PE typically causes obstructive shock. This leads to an **increase in CVP** because the right heart struggles to pump blood against the pulmonary obstruction (Right Heart Strain). * **Hypervolemia:** This would manifest as an **increase in CVP** (usually >15 cm H₂O) along with signs of fluid overload like pulmonary edema or raised JVP. * **Positive-Pressure Ventilation:** While it can decrease venous return, it typically causes a **falsely elevated CVP** reading because the increased intrathoracic pressure is transmitted to the vena cava and right atrium. **Clinical Pearls for NEET-PG:** * **CVP Trends:** Always look at the trend rather than a single value. A falling CVP in a surgical patient suggests fluid loss or distributive shock (sepsis/anaphylaxis). * **Shock Differentiation:** * *Hypovolemic/Distributive:* Low CVP. * *Cardiogenic/Obstructive:* High CVP. * **Sepsis Timeline:** Postoperative sepsis from an anastomotic leak or peritonitis typically manifests between postoperative days 3 and 7.

Q: What is the first sign of burst abdomen?

Serosanguinous drainage. **Explanation:** **Burst Abdomen (Abdominal Wound Dehiscence)** refers to the partial or complete separation of the layers of a surgical wound before complete healing has occurred. **1. Why Serosanguinous Drainage is Correct:** The hallmark clinical sign of an impending burst abdomen is the sudden discharge of **serosanguinous (pinkish) fluid** from the wound, often described as a "salmon-colored" discharge. This occurs because the deeper layers (fascia) have separated, allowing peritoneal fluid mixed with a small amount of blood to seep through the skin incision. This typically occurs between the **6th and 10th postoperative days**. **2. Analysis of Incorrect Options:** * **A. Bleeding at the site:** While minor oozing can occur, frank bleeding is more characteristic of immediate postoperative complications like reactionary hemorrhage or a slipped ligature, rather than fascial dehiscence. * **C. Pain at the site:** Interestingly, burst abdomen is often **painless**. Patients frequently report a sensation of "something giving way" after a bout of coughing or straining, but acute pain is rarely the presenting sign. **3. NEET-PG High-Yield Pearls:** * **The "Pink Discharge" Sign:** If a question mentions "serosanguinous soakage of dressings" on day 7-8, the diagnosis is always burst abdomen. * **Risk Factors:** Increased intra-abdominal pressure (coughing, vomiting, ascites), malnutrition (hypoalbuminemia), anemia, malignancy, and poor surgical technique (e.g., sutures placed too close to the edge). * **Management:** * **Immediate:** Cover the wound with sterile saline-soaked gauze and provide abdominal binders. * **Definitive:** Urgent surgical re-closure (tension-free) using non-absorbable sutures (e.g., Prolene) often via **interrupted "internal" or "mass" closure.**

Q: A 65-year-old man is being evaluated for possible right pneumonectomy for bronchogenic carcinoma. Which value is most suggestive of postoperative problems?

PaCO2 50 torr. ### Explanation The preoperative assessment for lung resection (pneumonectomy) focuses on the patient’s ability to tolerate a significant reduction in pulmonary reserve. **Why PaCO2 50 torr is the Correct Answer:** Hypercapnia (**PaCO2 > 45 mmHg**) is a strong independent predictor of poor postoperative outcomes and increased mortality in thoracic surgery. It indicates that the patient is already failing to maintain adequate alveolar ventilation with two lungs; removing one lung would likely lead to severe respiratory failure. Traditionally, a PaCO2 > 45 mmHg was considered an absolute contraindication to pneumonectomy. **Analysis of Incorrect Options:** * **A. DLCO 55% predicted:** While a DLCO 2L** is generally considered safe for pneumonectomy. The "rule of thumb" is that a predicted postoperative (ppo) FEV1 should be **> 0.8L** or **> 40%** of predicted to avoid ventilator dependence. * **C. MVO2 12 mL/kg/min:** Maximal oxygen uptake (VO2 max) is the gold standard for assessing cardiopulmonary reserve. A value **> 15 mL/kg/min** is safe, while ** 80%, no further testing is needed. * **The "80-40" Rule:** FEV1/DLCO > 80% (Safe), 45 mmHg, PaO2 < 50-60 mmHg, and ppoFEV1 < 0.8L are classic indicators of poor surgical candidacy.

Question 1

A 65-year-old man undergoes a technically difficult abdominoperineal resection for a rectal cancer during which he receives three units of packed red blood cells. Four hours later in the intensive care unit he is bleeding heavily from his perineal wound. Emergency coagulation studies reveal normal prothrombin, partial thromboplastin, and bleeding times. The fibrin degradation products are not elevated but the serum fibrinogen content is depressed and the platelet count is 70,000/mL. What is the most likely cause of the bleeding?

Accepted Answer

A bleeding blood vessel in the surgical field

Answer

Delayed blood transfusion reaction

Answer

Autoimmune fibrinolysis

Answer

Factor VIII deficiency

Question 2

Following splenectomy in children, which one of the following is recommended?

Accepted Answer

Pneumococcal vaccination

Answer

Hepatitis B vaccination

Answer

Typhoid vaccination

Answer

Regular follow-up

Question 3

When should antibiotics be given for surgical prophylaxis?

Accepted Answer

1 hour before surgery

Answer

1 hour after surgery

Answer

2 hours before surgery

Answer

2 hours after surgery

Question 4

A 42-year-old man has had a rocky course for the 3 days following a bowel resection for intestinal perforation due to inflammatory bowel disease. His central venous pressure (CVP) had been 12 to 14 but is now 6, in the face of diminished blood pressure and oliguria. Which of the following is the most likely etiology of his hypotension?

Accepted Answer

Gram-negative sepsis

Answer

Pulmonary embolism

Answer

Hypervolemia

Answer

Positive-pressure ventilation

Question 5

A 70-year-old woman has a small-bowel fistula with an output of 1.5 L/d. Replacement of daily losses should be handled using which of the following fluid solutions based on its composition in mEq/L?

Accepted Answer

Solution A composition

Answer

Solution B composition

Answer

Solution C composition

Answer

Solution D composition

Question 6

What is the first sign of burst abdomen?

Accepted Answer

Serosanguinous drainage

Answer

Bleeding at the site

Answer

Pain at the site

Answer

None of the above

Question 7

A 68-year-old hypertensive man undergoes successful repair of a ruptured abdominal aortic aneurysm. He receives 9 L Ringer's lactate solution and 4 units of whole blood during the operation. Two hours after transfer to the surgical intensive care unit, the following hemodynamic parameters are obtained: systemic blood pressure (BP) 90/60 mm Hg, pulse 110 beats per minute, central venous pressure (CVP) 7 mm Hg, pulmonary artery pressure 28/10 mm Hg, pulmonary capillary wedge pressure (PCWP) 8 mm Hg, cardiac output 1.9 L/min, systemic vascular resistance 1400 (dyne*s)/cm5 (normal is 900-1300), PaO2 140 mm Hg (FiO2: 0.45), urine output 15 mL/h (specific gravity: 1.029), and hematocrit 35%. Given this data, which of the following is the most appropriate next step in management?

Accepted Answer

Administration of a fluid challenge to increase urine output

Answer

Administration of a diuretic to increase urine output

Answer

Administration of a vasopressor agent to increase systemic blood pressure

Answer

Administration of a vasodilating agent to decrease elevated systemic vascular resistance

Question 8

Which of the following is NOT true about the principal hormonal responses to surgical stress?

Accepted Answer

Increased level of thyroxine

Answer

Increased level of ACTH

Answer

Increased level of growth hormone

Answer

Decreased level of insulin

Question 9

A 59-year-old man is planning to undergo coronary artery bypass surgery. He has osteoarthritis and consumes nonsteroidal anti-inflammatory drugs (NSAIDs) for the pain. Which of the following is the most appropriate treatment prior to surgery to minimize his risk of bleeding from his NSAID use?

Accepted Answer

Stop the NSAIDs 3 to 4 days prior to surgery.

Answer

Begin vitamin K 1 week prior to surgery.

Answer

Give fresh frozen plasma (FFP) a few hours before surgery.

Answer

Stop the NSAIDs 1 week prior to surgery.

Question 10

A 65-year-old man is being evaluated for possible right pneumonectomy for bronchogenic carcinoma. Which value is most suggestive of postoperative problems?

Accepted Answer

PaCO2 50 torr

Answer

Carbon monoxide diffusion capacity (DLCO) 55 percent predicted

Answer

Forced expiratory volume in 1 second (FEV1) 2L (83 percent of total forced vital capacity)

Answer

Maximal oxygen uptake (MVO2) 12 mL/kg/min

Preoperative and Postoperative Care — MCQs

Preoperative and Postoperative Care — MCQs

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