Preoperative and Postoperative Care — MCQs

Preoperative and Postoperative Care Indian Medical PG Practice Questions and MCQs

Question 201: After an operation on the femur, chest X-ray shows widespread mottling throughout the lung field like a snowstorm. It is diagnostic of

A. Fat embolism (Correct Answer)
B. Atelectasis
C. Shock lung
D. Bronchopneumonia

Explanation: ***Fat embolism*** - A **snowstorm appearance** or **diffuse intraparenchymal opacities** on a chest X-ray, along with a history of **long bone fracture** (like the femur), is highly characteristic of fat embolism syndrome. - Fat embolism occurs when fat droplets enter the bloodstream after trauma to fat-containing tissues, leading to lung injury and respiratory distress. *Atelectasis* - Refers to the **collapse of lung tissue**, often appearing as an area of increased opacification with **volume loss** on X-ray, which is different from a "snowstorm" pattern. - It usually results from airway obstruction or hypoventilation, not typically associated with widespread mottling. *Shock lung* - This is an older term often used to describe **Acute Respiratory Distress Syndrome (ARDS)**, which presents with diffuse bilateral infiltrates. - While ARDS can be a complication of severe trauma or systemic inflammatory response, the "snowstorm" pattern in the context of a recent femur operation is more specific to fat embolism. *Bronchopneumonia* - Typically presents with **patchy infiltrates** that may be bilateral but are usually more consolidated and localized to specific areas due to inflammation and infection in the bronchioles and alveoli. - It would also likely be accompanied by symptoms of infection, such as fever and productive cough, which are not mentioned here.

Question 202: Which of the following is the LEAST significant risk factor for postoperative pulmonary complications?

A. Age > 60 years (Correct Answer)
B. ASA class 3 and 4 patients
C. Longer surgeries >2 hr
D. Upper Abdominal surgery

Explanation: ***Age > 60 years*** - While age is a factor, it is generally considered **less significant** than other comorbid conditions or surgical factors in predicting postoperative pulmonary complications. - Pulmonary function naturally declines with age, but healthy elderly individuals may still tolerate surgery well if other risk factors are controlled. *ASA class 3 and 4 patients* - Patients classified as **ASA (American Society of Anesthesiologists) 3 or 4** have severe systemic disease or life-threatening systemic disease, respectively. - This significantly increases their risk of **postoperative pulmonary complications** due to their underlying health issues. *Longer surgeries >2 hr* - **Prolonged duration of surgery** (typically defined as >2-3 hours) is a significant independent risk factor for pulmonary complications. - This is due to longer periods of **immobility**, ventilation, and exposure to anesthetics, contributing to atelectasis and pneumonia risk. *Upper Abdominal surgery* - **Upper abdominal surgery** is one of the highest risk categories for postoperative pulmonary complications. - Incisions in this area can cause *diaphragmatic dysfunction*, pain leading to shallow breathing, and impaired cough reflex.

Question 203: A key clinical finding in post-operative ileus is:

A. No intestinal sounds heard (Correct Answer)
B. Is due to hypernatremia
C. Intestinal peristalsis never becomes normal again
D. Begins 2-3 days post-operatively

Explanation: ***No intestinal sounds heard*** - Postoperative ileus is characterized by a temporary arrest of **bowel peristalsis**, leading to absent or markedly decreased bowel sounds upon auscultation. - This lack of sounds is a key clinical indicator of the gut's inability to propel contents normally. *Is due to hypernatremia* - Postoperative ileus is primarily caused by multifactorial physiologic responses to surgery, including **inflammation**, **opioid use**, and **sympathetic nervous system overactivity**, not hypernatremia. - While electrolyte imbalances can contribute to gut dysmotility, hypernatremia is not the direct or primary cause of paralytic ileus. *Intestinal peristalsis never becomes normal again* - Postoperative ileus is typically a **self-limiting condition** where intestinal peristalsis eventually returns to normal. - While it can sometimes be prolonged or recurrent, it does not imply a permanent loss of intestinal function. *Begins 2-3 days post-operatively* - Postoperative ileus typically begins **immediately after surgery** and usually resolves within **2 to 3 days**, though its duration can vary depending on the surgical procedure and individual patient factors. - Its onset is directly linked to the surgical insult, not a delayed presentation.

Question 204: What is the most common cause of hyponatremia in surgical practice?

A. Electrolyte loss due to duodenal fistula
B. Electrolyte loss due to pancreatic fistula
C. Intussusception causing bowel obstruction
D. Fluid shifts in small intestinal obstruction (Correct Answer)

Explanation: ***Fluid shifts in small intestinal obstruction*** - In **small intestinal obstruction**, fluid and electrolytes accumulate in the **dilated bowel loops**, a phenomenon known as "third spacing." - This leads to **intravascular volume depletion** and subsequent release of **antidiuretic hormone (ADH)**, causing water retention and dilutional hyponatremia. *Electrolyte loss due to duodenal fistula* - While a **duodenal fistula** can cause significant electrolyte loss, leading to hyponatremia, it is a less common clinical scenario compared to **small bowel obstruction**. - The fluid loss in a duodenal fistula is generally **hypotonic**, meaning it contains less sodium than plasma, contributing to hyponatremia. *Electrolyte loss due to pancreatic fistula* - A **pancreatic fistula** can lead to significant fluid and electrolyte loss, particularly of bicarbonate and potassium, but direct sodium loss is usually not as prominent as in small bowel obstruction. - While it can contribute to **dehydration**, it's a less common cause of hyponatremia in surgical patients than the widespread fluid shifts in obstruction. *Intussusception causing bowel obstruction* - **Intussusception** is a cause of bowel obstruction, and it leads to hyponatremia through the same mechanism of **fluid shifts** and third-spacing. - However, "fluid shifts in small intestinal obstruction" is a broader, more encompassing description of the most common cause, of which intussusception is one specific etiology.

Question 205: Postoperative third-space accumulation should be managed by intravenous fluid with

A. Albumin
B. Normal saline (Correct Answer)
C. Fluid restriction
D. Dextrose in water

Explanation: ***Normal saline*** - **Third-space accumulation** leads to fluid shifts from the intravascular space to the interstitial space, commonly seen after trauma or surgery, resulting in **hypovolemia**. - **Isotonic solutions** like normal saline help replenish the lost intravascular volume and maintain blood pressure without shifting more fluid into the third space. *Albumin* - While albumin can increase oncotic pressure and draw fluid back into the intravascular space, it is typically reserved for cases of **severe hypoalbuminemia** or when crystalloids alone are insufficient. - Using albumin in the setting of acute third-space loss without clear indications of hypoalbuminemia may not be the initial or most appropriate intervention. *Fluid restriction* - **Fluid restriction** would worsen the patient's hypovolemia as third-space losses deplete the effective circulating volume of the patient. - This approach is appropriate for conditions like **heart failure** or **SIADH**, where there is true fluid excess or impaired excretion, not for hypovolemic states due to fluid shifts. *Dextrose in water* - Dextrose in water is a **hypotonic solution** that would rapidly distribute into the intracellular and interstitial compartments and may contribute to worsening edema in the third space. - It does not effectively expand intravascular volume and can lead to **hyponatremia** if administered in large quantities.

Question 206: Which of the following is true about the immediate postoperative period in a young patient with previously normal lungs having upper abdominal surgery?

A. Diffusion hypoxia is the major determinant of arterial hypoxaemia
B. The CXR will typically reveal no abnormalities
C. Arterial oxygen tension will normalize after 15 minutes
D. Arterial oxygen tension will typically be reduced by an average of 10 mm Hg when breathing room air (Correct Answer)

Explanation: **Arterial oxygen tension will typically be reduced by an average of 10 mm Hg when breathing room air** - Even in young patients with previously normal lungs undergoing upper abdominal surgery, a mild to moderate reduction in **arterial oxygen tension (PaO2)** is common postoperatively due to changes in **lung mechanics and gas exchange**. - This reduction is often around **10 mmHg** and is a consequence of factors like **atelectasis**, altered **ventilation-perfusion (V/Q) mismatch**, and reduced **functional residual capacity (FRC)**. *Diffusion hypoxia is the major determinant of arterial hypoxaemia* - **Diffusion hypoxia** (or the **Fink effect**) primarily occurs during the washout of nitrous oxide, where the rapid exit of N2O from the blood into the alveoli dilutes oxygen and carbon dioxide, leading to transient hypoxemia. - While it can contribute to *transient* hypoxemia immediately after N2O cessation, it is **not the major or sustained determinant** of arterial hypoxemia in the *overall immediate postoperative period* following upper abdominal surgery. *The CXR will typically reveal no abnormalities* - It is common for **chest X-rays (CXR)** in the immediate postoperative period after upper abdominal surgery to show **some abnormalities**, such as **basilar atelectasis** or small **pleural effusions**, even in patients with previously normal lungs. - These findings, though often mild, reflect the physiological changes and potential complications that can occur with surgical stress and altered breathing patterns. *Arterial oxygen tension will normalize after 15 minutes* - While the most acute effects of anesthesia and immediate recovery may subside in a short period, the physiological changes leading to reduced **arterial oxygen tension** after upper abdominal surgery often persist for **several hours to days**. - Factors such as pain, splinting, and altered breathing patterns contribute to ongoing **V/Q mismatch** and **atelectasis**, preventing rapid normalization of PaO2.

Question 207: Early movement following surgery for ankylosis is

A. Desirable (Correct Answer)
B. Harmful
C. Indicated only when ankylosis is one sided
D. Unimportant

Explanation: ***Desirable*** - Early movement following surgery for **ankylosis** is crucial for preventing **re-ankylosis** and promoting the formation of a **neocartilage-like layer**. - It helps maintain joint mobility, reduce stiffness, and improves long-term functional outcomes after procedures like **arthroplasty**. *Harmful* - Delays in movement can lead to increased fibrous tissue formation, limiting the newly created joint's mobility and potentially causing **re-ankylosis**. - Prolonged immobilization after joint surgery can also lead to muscle atrophy, contractures, and impaired circulation, hindering recovery. *Indicated only when ankylosis is one sided* - The principle of early movement applies to both **unilateral** and **bilateral ankylosis** to prevent recurrence and improve range of motion in the affected joint(s). - Focusing solely on unilateral cases overlooks the functional benefits of early mobilization for all patients undergoing such surgery. *Unimportant* - Early movement is a **critical component** of postoperative recovery, as it directly impacts the success of the surgical intervention by maintaining joint space and flexibility. - Neglecting early motion can compromise the surgical outcome, increasing the risk of stiffness, pain, and the need for further interventions.

Question 208: Most common cause of postoperative renal failure:

A. Decreased renal perfusion (Correct Answer)
B. Toxicity of anesthetic drugs
C. Toxicity of antibiotics
D. None of the options

Explanation: **Decreased renal perfusion** - **Hypovolemia** and **hypotension** during or after surgery are frequent causes of reduced blood flow to the kidneys, leading to **ischemic injury**. - This inadequate perfusion results in **acute tubular necrosis (ATN)**, which is the most common intrinsic cause of postoperative acute renal failure. - Accounts for the majority (50-80%) of postoperative acute kidney injury cases. *Toxicity of anesthetic drugs* - While some anesthetic agents, particularly older ones, could be nephrotoxic, modern anesthetics are generally **well-tolerated** by the kidneys and rarely cause direct renal failure. - **Nephrotoxicity** from anesthetic drugs is an uncommon cause compared to the widespread issue of inadequate renal perfusion during surgical stress. *Toxicity of antibiotics* - Certain antibiotics, such as **aminoglycosides** (e.g., gentamicin) and **vancomycin**, are known to be nephrotoxic. However, their use is often monitored, and renal failure due to antibiotic toxicity is less common and often preventable compared to hypovolemia. - **Antibiotic-induced nephrotoxicity** typically presents with ATN but is not the most frequent cause in the general postoperative population. *None of the options* - This option is incorrect because **decreased renal perfusion** is, in fact, a widely recognized and leading cause of postoperative renal failure.

Question 209: 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 210: A patient presents in coma for 20 days, what will be the best way to give him nutrition?

A. Ryle's tube feeding (Correct Answer)
B. Feeding via jejunostomy
C. Parenteral nutrition
D. Oral feeding

Explanation: ***Ryle's tube feeding*** - A **Ryle's tube (nasogastric tube)** is the most appropriate method for enteral feeding in a patient who has been in coma for **20 days (~3 weeks)**. - **Current guidelines** recommend NG tube feeding for durations up to **4-6 weeks**, making it suitable for this patient's timeline. - NG tube placement is **non-invasive, quick to establish**, and provides effective enteral nutrition while the patient's neurological status is being assessed and managed. - The gastrointestinal tract is functioning (no contraindication mentioned), making enteral feeding via NG tube the preferred route following the principle: **"If the gut works, use it."** - Proper positioning (head elevation 30-45°) and monitoring can minimize aspiration risk in comatose patients. *Feeding via jejunostomy* - **Jejunostomy** or PEG tube placement is considered for **long-term feeding beyond 4-6 weeks**. - At 20 days, it is **premature** to proceed with a surgical/endoscopic procedure for feeding access unless there are specific indications (recurrent aspiration despite NG feeding, NG tube intolerance, anticipated prolonged need beyond 6 weeks). - Jejunostomy requires a surgical procedure with associated risks and is reserved for patients clearly requiring extended nutritional support. *Parenteral nutrition* - **Parenteral nutrition** (intravenous feeding) is indicated when the gastrointestinal tract is **non-functional** or enteral access is impossible. - Since the question doesn't mention GI dysfunction, enteral feeding is preferred as it maintains gut integrity, is more physiological, safer, and more cost-effective. - Parenteral nutrition carries risks of catheter-related infections, metabolic complications, and gut mucosal atrophy. *Oral feeding* - **Oral feeding** is absolutely contraindicated in a comatose patient due to absent protective airway reflexes and extremely high risk of **aspiration pneumonia**. - A patient in coma cannot safely swallow and protect their airway during oral intake.

Practice by Chapter

Preoperative Risk Assessment

Practice Questions

Perioperative Management of Comorbidities

Practice Questions

Preparation of Patient for Surgery

Practice Questions

Informed Consent Process

Practice Questions

Post-Anesthesia Care

Practice Questions

Pain Management

Practice Questions

Wound Care and Dressings

Practice Questions

Drain Management

Practice Questions

Postoperative Complications Detection

Practice Questions

Early Ambulation and Rehabilitation

Practice Questions

Enhanced Recovery After Surgery (ERAS) Protocols

Practice Questions

Discharge Planning and Follow-up

Practice Questions

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