Prevention Strategies — MCQs
A patient with a non-obstructing carcinoma of the sigmoid colon is being prepared for elective resection. To minimize the risk of postoperative infectious complications, what should be included in your planning?
What is the optimal timing for administering antibiotic prophylaxis before surgery?
What is the term for bacteria that are actively dividing and have invaded the wound surface in the context of surgical site infection?
When do we have to start antibiotics to prevent post-operative infection?
Which of the following is true regarding prophylactic antibiotic use in surgical practice?
Preferred time for prophylactic antibiotic administration for surgery?
Untidy wounds are characterised by which of the following? 1. Crushed or avulsed tissues 2. Contaminated wound 3. Devitalised tissue 4. No loss of tissue
What is the type of incision commonly used in pancreaticoduodenectomy?
Which of the following statements are correct regarding sutures in surgery? I. Barbed sutures have the advantage of eliminating the need for knots. II. Vertical mattress sutures help in eversion of wound edges. III. Aberdeen knot is used for continuous suturing. IV. Silk is preferred for subcuticular suturing. Select the answer using the code given below :
A man is brought to casualty who met with an accident. He sustained multiple rib fractures with paradoxical movement of chest. Management is
Prevention Strategies Indian Medical PG Practice Questions and MCQs
Question 1: A patient with a non-obstructing carcinoma of the sigmoid colon is being prepared for elective resection. To minimize the risk of postoperative infectious complications, what should be included in your planning?
- A. Postoperative administration for 5 to 7 days of parenteral antibiotics effective against aerobes and anaerobes
- B. A single preoperative parenteral dose of antibiotic effective against aerobes and anaerobes may provide initial coverage. (Correct Answer)
- C. Postoperative administration for 2 to 4 days of parenteral antibiotics effective against aerobes and anaerobes
- D. Avoidance of oral antibiotics to prevent emergence of Clostridioides difficile
Explanation: ***Single preoperative parenteral dose of antibiotic effective against aerobes and anaerobes*** - For **elective colorectal surgery**, a single dose of a **broad-spectrum parenteral antibiotic** administered within 60 minutes prior to incision is the standard of care to reduce surgical site infections. - This approach ensures adequate drug levels in the tissues during the period of potential bacterial contamination and is a cornerstone of modern surgical prophylaxis. - Current guidelines (WHO, SCIP) recommend a single preoperative dose, which may be redosed intraoperatively if the procedure is prolonged beyond 3-4 hours. *Avoidance of oral antibiotics to prevent emergence of Clostridioides difficile* - This is **incorrect**. **Oral antibiotics** (such as neomycin and metronidazole) are routinely used preoperatively in conjunction with mechanical bowel preparation for colorectal surgery to reduce intraluminal bacterial load. - The concern for *Clostridioides difficile* infection is generally low with short-term, targeted prophylactic antibiotic regimens compared to broad-spectrum, prolonged use. - The combination of oral and parenteral antibiotics has been shown to further reduce surgical site infections. *Postoperative administration for 5 to 7 days of parenteral antibiotics* - **Prolonged postoperative antibiotic administration** beyond 24 hours in uncomplicated cases is not recommended as it increases the risk of **antibiotic resistance**, *C. difficile* infection, and adverse drug reactions without additional benefit. - The goal of prophylactic antibiotics is to cover the period of contamination during surgery, not to treat presumed ongoing infection postoperatively. *Postoperative administration for 2 to 4 days of parenteral antibiotics* - While administration for up to 24 hours post-operatively may be considered in some high-risk cases, routine **prolonged postoperative antibiotics** (2-4 days) are unnecessary for most elective colorectal resections. - Evidence suggests that continuing antibiotics beyond the immediate perioperative period does not further reduce the incidence of **surgical site infections** in clean-contaminated surgeries.
Question 2: What is the optimal timing for administering antibiotic prophylaxis before surgery?
- A. Immediately before induction of anesthesia
- B. 30-60 minutes before incision (Correct Answer)
- C. 2-3 hours before surgery
- D. Immediately after surgery
Explanation: ***30-60 minutes before incision*** - This is the **optimal timing** recommended by WHO, CDC, and major surgical guidelines for most commonly used prophylactic antibiotics (cefazolin, cefuroxime). - Ensures **peak tissue and serum concentrations** are achieved at the time of incision, providing maximum protection against surgical site infections. - Based on **pharmacokinetic principles**: the antibiotic must be present at bactericidal concentrations in tissues when bacterial contamination occurs. - Studies show this timing significantly reduces surgical site infection rates compared to other timings. *Immediately before induction of anesthesia* - While acceptable in some protocols, this may be too early if there is a delay between induction and incision. - Could result in **declining antibiotic levels** by the time the incision is made, especially for antibiotics with shorter half-lives. *2-3 hours before surgery* - This is **too early** for most antibiotics. - Tissue levels may have already **declined below therapeutic concentrations** by the time of incision. - Does not provide adequate protection during the critical period of bacterial contamination. *Immediately after surgery* - This is **treatment, not prophylaxis**. - Offers **no preventive benefit** against intraoperative contamination. - By this time, bacteria introduced during surgery have already adhered to tissues and begun forming biofilms.
Question 3: What is the term for bacteria that are actively dividing and have invaded the wound surface in the context of surgical site infection?
- A. Contamination
- B. Colonization
- C. Local infection
- D. Infection (Correct Answer)
Explanation: ***Infection*** - This term precisely describes bacteria that are **actively dividing** and have **invaded the host tissue**, causing a clinical infection with tissue damage and host immune response. - In surgical site infections, this represents the stage where microorganisms have overcome host defenses and are causing disease. - This is the standard terminology used in surgical literature to describe the progression from contamination to active disease. *Contamination* - **Contamination** refers to the presence of microorganisms on a surface or in a wound without active proliferation or host response. - It's an early stage where bacteria are present but not yet multiplying or causing disease. *Colonization* - **Colonization** indicates that microorganisms are replicating on the host surface or in a wound without tissue invasion or causing an immune response. - Unlike infection, colonization does not involve invasion of tissue or clinical signs of disease. *Local infection* - While this describes an infection confined to a particular anatomical area, it is a descriptor of the **location** rather than the **process** described in the question. - The question asks specifically about the term for dividing and invading bacteria, which is simply "infection" - the word "local" adds information about location but doesn't define the fundamental process.
Question 4: When do we have to start antibiotics to prevent post-operative infection?
- A. 1 week before surgery
- B. 2 days before surgery
- C. After surgery
- D. 30-60 minutes before incision (up to 24 hours post-op) (Correct Answer)
Explanation: ***30-60 minutes before incision (up to 24 hours post-op)*** - Surgical antibiotic prophylaxis (SAP) should be administered **30-60 minutes before surgical incision** to ensure adequate tissue and serum concentrations at the time of incision. - This timing allows optimal drug distribution to surgical tissues, which is crucial for preventing surgical site infections (SSIs). - For most clean and clean-contaminated surgeries, prophylaxis should be limited to a **single dose** or continued for **maximum 24 hours post-operatively** as per WHO and CDC guidelines. - Prolonged post-operative antibiotics beyond 24 hours do **not** reduce infection rates and increase the risk of **antibiotic resistance** and **adverse effects**. *1 week before surgery* - Administering antibiotics this far in advance is **unnecessary** and **ineffective** for surgical prophylaxis. - It increases the risk of **antibiotic resistance** and does not guarantee adequate drug levels at the time of incision. - Pre-operative antibiotic use should be avoided unless treating an active infection. *2 days before surgery* - This timeframe is too early to achieve prophylactic benefit during the surgical procedure. - Prolonged pre-operative use promotes **bacterial resistance** without providing additional protection. - Drug levels will not be optimal at the time of incision due to metabolism and excretion. *After surgery* - Starting antibiotics **after surgical incision** is **too late** for prophylaxis as contamination has already occurred. - Post-operative initiation is considered **therapeutic treatment** for established infection, not prevention. - The critical window for prophylaxis is the period from skin incision to wound closure.
Question 5: Which of the following is true regarding prophylactic antibiotic use in surgical practice?
- A. is given orally
- B. continued for a minimum of 7 days
- C. first dose is given before induction of anesthesia (Correct Answer)
- D. depends on individual preference
Explanation: ***First dose is given before induction of anesthesia*** - **Prophylactic antibiotics** are most effective when present in adequate concentrations in tissue **before the surgical incision** is made - Administering the first dose **within 60 minutes before incision** (typically before induction of anesthesia) ensures optimal tissue levels at the time of potential bacterial contamination - This timing is a **key principle** of effective surgical antibiotic prophylaxis *Is given orally* - Surgical prophylaxis requires **intravenous administration** for rapid and reliable tissue levels - IV route ensures predictable bioavailability and adequate drug concentration at the surgical site - Oral route may be used in specific outpatient scenarios but is **not standard** for surgical prophylaxis *Continued for a minimum of 7 days* - Prophylactic antibiotics are given for **short duration**: typically a **single dose** or continued for less than 24 hours post-operatively - Extended courses (≥7 days) are reserved for **treating established infections**, not prophylaxis - Prolonged use increases risk of **antibiotic resistance**, adverse effects, and *Clostridioides difficile* infection *Depends on individual preference* - Prophylactic antibiotic use follows **evidence-based guidelines** and institutional protocols, not individual preference - Guidelines consider surgery type, patient risk factors, local **antibiogram data**, and established efficacy - Standardized protocols improve outcomes and reduce surgical site infections
Question 6: Preferred time for prophylactic antibiotic administration for surgery?
- A. 1 day before surgery
- B. At the time of induction of anaesthesia (Correct Answer)
- C. I.V. during surgery
- D. I.M. 6 hrs before surgery
Explanation: ***At the time of induction of anaesthesia*** - This timing ensures that a **therapeutic concentration** of the antibiotic is present in the tissues at the time of the initial surgical incision, when the risk of bacterial contamination is highest. - Administering the antibiotic too early or too late can reduce its effectiveness in preventing **surgical site infections (SSIs)**. *1 day before surgery* - Administering antibiotics a day before surgery would lead to the drug being **metabolized and eliminated** from the body before the surgical incision is made, rendering it ineffective for prophylaxis. - This timing also increases the risk of **antibiotic resistance** development without providing adequate protection against SSIs. *I.V. during surgery* - Administering the antibiotic intravenously during surgery means that the drug will not have reached sufficient **tissue concentrations** at the crucial moment of the initial incision. - The protective effect is largely dependent on adequate tissue levels **prior to contamination**, which would not be achieved by administration only during the procedure. *I.M. 6 hrs before surgery* - While closer to the optimal timing than 1 day before, administering intramuscularly 6 hours prior may result in **suboptimal drug levels** at the time of incision, especially for drugs with shorter half-lives. - Intramuscular administration can also have variable absorption rates compared to intravenous, potentially delaying peak tissue concentration and reducing reliability for **prophylactic efficacy**.
Question 7: Untidy wounds are characterised by which of the following? 1. Crushed or avulsed tissues 2. Contaminated wound 3. Devitalised tissue 4. No loss of tissue
- A. 1, 2, 3 and 4
- B. 1, 2 and 4
- C. 1, 2 and 3 (Correct Answer)
- D. 2, 3 and 4
Explanation: ***1, 2 and 3*** - **Untidy wounds**, often resulting from high-energy trauma, are defined by the presence of **crushed or avulsed tissues**, **contamination**, and **devitalized tissue**. - These characteristics make the wound more complex to manage and prone to complications like infection. *1, 2, 3 and 4* - This option incorrectly includes "no loss of tissue" (option 4) as a characteristic of untidy wounds. **Untidy wounds** frequently involve **tissue loss**, making this statement contradictory to their definition. - The presence of **crushed or avulsed tissues** inherently suggests some degree of tissue damage or loss. *1, 2 and 4* - This option incorrectly states that "no loss of tissue" is a characteristic of untidy wounds. In reality, **untidy wounds** are often associated with significant **tissue destruction and loss**. - **Crushed and avulsed tissues** are direct indicators of tissue damage and potential loss. *2, 3 and 4* - This option incorrectly omits "crushed or avulsed tissues" (option 1), which is a cardinal feature of untidy wounds. It also incorrectly includes "no loss of tissue" (option 4). - While **contamination** and **devitalized tissue** are hallmarks of untidy wounds, the absence of crushed/avulsed tissue and the idea of no tissue loss are inaccurate.
Question 8: What is the type of incision commonly used in pancreaticoduodenectomy?
- A. Chevron incision (Correct Answer)
- B. Lanz incision
- C. Maylard incision
- D. Kocher's incision
Explanation: ***Chevron incision*** - A **chevron incision** (also known as a rooftop or bilateral subcostal incision) provides **excellent exposure** to the upper abdomen, making it ideal for complex procedures like **pancreaticoduodenectomy** (Whipple procedure). - This incision allows for wide access to the **pancreas**, **duodenum**, **biliary tree**, and **major vessels**, facilitating the extensive dissection and reconstruction required. *Kocher's incision* - **Kocher's incision** is a right subcostal incision typically used for procedures on the **gallbladder** and **biliary tree**. - It does not offer sufficient exposure for the extensive and multi-quadrant dissection required during a **pancreaticoduodenectomy**. *Lanz incision* - A **Lanz incision** is a short, oblique incision in the right lower quadrant, primarily used for **appendectomy**. - This incision is far too small and incorrectly located to be used for any upper abdominal surgery, let alone a **pancreaticoduodenectomy**. *Maylard incision* - The **Maylard incision** is a transverse incision made in the lower abdomen, commonly used for **gynecological** and **urological** procedures. - It is unsuitable for upper abdominal operations such as a **pancreaticoduodenectomy** due to its low anatomical position.
Question 9: Which of the following statements are correct regarding sutures in surgery? I. Barbed sutures have the advantage of eliminating the need for knots. II. Vertical mattress sutures help in eversion of wound edges. III. Aberdeen knot is used for continuous suturing. IV. Silk is preferred for subcuticular suturing. Select the answer using the code given below :
- A. I, II and IV
- B. II, III and IV
- C. I, II and III (Correct Answer)
- D. I, III and IV
Explanation: ***I, II and III*** - **I. Barbed sutures** have unidirectional or bidirectional barbs that grip tissue, negating the need for traditional knots to secure the suture line. This property can significantly **reduce operating time** and the volume of foreign material left in the wound. - **II. Vertical mattress sutures** are designed to achieve precise wound edge approximation and eversion, which are crucial for optimal healing and cosmesis, particularly in areas under tension or for thick skin. - **III. The Aberdeen knot** is a slip knot technique specifically designed to secure the end of a **continuous suture line** efficiently and reliably. It provides a flat, secure knot that minimizes bulk and is less prone to loosening. *I, II and IV* - While statements I and II are correct, statement IV is incorrect. **Silk is a braided, non-absorbable multifilament suture** that can cause significant tissue reaction. - It is generally not preferred for subcuticular suturing due to its increased risk of infection, visibility, and foreign body reaction compared to monofilament, absorbable sutures. *II, III and IV* - Statements II and III are correct, but statement IV is incorrect. **Silk is avoided for subcuticular closure** due to its inflammatory properties and potential for suture extrusion or sinus formation. - Subcuticular sutures typically use **absorbable monofilament sutures** (e.g., poliglecaprone 25 or polydioxanone) to minimize tissue reaction and achieve good cosmetic results. *I, III and IV* - Statements I and III are correct regarding barbed sutures and the Aberdeen knot, respectively. However, statement IV is incorrect because **silk suture is a non-absorbable, braided material that is highly reactive and not suitable for subcuticular placement**, where monofilament absorbable sutures are preferred for minimal tissue reaction and good cosmesis.
Question 10: A man is brought to casualty who met with an accident. He sustained multiple rib fractures with paradoxical movement of chest. Management is
- A. Consult cardiothoracic surgeon
- B. Tracheostomy
- C. Strapping
- D. Intermittent positive pressure ventilation (Correct Answer)
Explanation: ***Intermittent positive pressure ventilation*** - **Paradoxical movement of the chest** (flail chest) indicates instability of the chest wall, impairing effective ventilation. - **Intermittent positive pressure ventilation (IPPV)** helps to stabilize the chest wall internally by applying positive pressure, improving oxygenation and reducing the work of breathing. *Consult cardiothoracic surgeon* - While a cardiothoracic surgeon might be involved for severe cases or surgical fixation, **immediate management for respiratory compromise due to flail chest** is focused on ventilation support. - Consulting a surgeon would be part of a broader management plan, but not the primary immediate intervention for ventilatory failure. *Tracheostomy* - **Tracheostomy** is a surgical procedure to create an airway, typically considered for long-term ventilation or upper airway obstruction. - It is not the immediate intervention for acute flail chest, as **endotracheal intubation** for IPPV would be performed first if needed. *Strapping* - **Strapping** the chest (e.g., with tape or bandages) is **contraindicated** in flail chest. - It restricts chest wall movement unnecessarily, **impairs ventilation**, and can exacerbate respiratory distress and atelectasis.
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