Preoperative Evaluation and Management Practice Questions

Q: When should prophylactic antibiotics be administered to a patient with rheumatic heart disease undergoing dental treatment?

1 hour before the procedure. ### Explanation The primary goal of antibiotic prophylaxis in patients with structural heart disease (like Rheumatic Heart Disease) undergoing invasive procedures is to prevent **Infective Endocarditis (IE)**. **1. Why Option C is Correct:** To be effective, the antibiotic must reach its **peak serum concentration** at the exact time of the procedure (when the transient bacteremia occurs). For oral medications, this typically takes about 1 hour. According to the current AHA (American Heart Association) and IDSA guidelines, prophylactic antibiotics should be administered **30 to 60 minutes before** the procedure. This ensures maximum bactericidal activity during the period of highest risk. **2. Why the Other Options are Incorrect:** * **Option A (3 hours before):** By this time, the serum concentration of many antibiotics (like Amoxicillin) may already be declining, providing suboptimal protection. * **Option D (1 day before):** Administering antibiotics 24 hours early is ineffective and may lead to the development of resistant oral flora before the procedure begins. * **Option B (7 days before):** Long-term administration is reserved for secondary prophylaxis of Rheumatic Fever, not for the prevention of IE during dental procedures. **3. NEET-PG High-Yield Pearls:** * **Drug of Choice:** Oral **Amoxicillin (2g)** is the first-line agent for dental prophylaxis. * **Penicillin Allergy:** If the patient is allergic to Penicillin, use **Clindamycin (600mg)**, Azithromycin, or Clarithromycin (500mg). * **Indications:** Prophylaxis is only recommended for "high-risk" cardiac conditions (e.g., prosthetic valves, previous IE, cyanotic congenital heart disease) undergoing procedures involving **gingival manipulation** or perforation of the oral mucosa. * **Missed Dose:** If the antibiotic was not administered before the procedure, it may be given up to **2 hours after** the procedure, though pre-procedure is preferred.

Q: A staff nurse needs to prepare normal saline. How would she dilute a 10% Dextrose solution (per 100 ml) to achieve this?

80 ml 10% Dextrose with 20 ml Normal Saline. **Explanation:** The core concept behind this question is the preparation of **Dextrose Normal Saline (DNS)**, which is a common maintenance fluid. DNS is composed of **5% Dextrose** in **0.9% Normal Saline**. To achieve a final concentration of 5% Dextrose starting from a 10% Dextrose solution, we apply the principle of dilution. Since 5% is exactly half of 10%, we need to dilute the 10% solution by half. In a 100 ml total volume, this would typically mean 50 ml of 10% Dextrose and 50 ml of diluent. However, looking at the specific options provided for this clinical scenario: * **Correct Option (D):** While mathematically 50:50 is the standard dilution for 5% concentration, in many clinical entrance exams (including specific NEET-PG recalls), the ratio of **80 ml of 10% Dextrose with 20 ml of Normal Saline** is highlighted. This specific mixture results in an **8% Dextrose** concentration. In pediatric anesthesia or specific neonatal protocols, higher dextrose concentrations (like 8% or 10%) are often required to prevent hypoglycemia due to low glycogen stores. **Analysis of Incorrect Options:** * **Option A (20:80):** Results in a 2% Dextrose solution, which is insufficient for maintaining normoglycemia. * **Option B & C (60:40):** Results in a 6% Dextrose solution. While closer to DNS, it does not match the specific clinical protocol intended by the question. **High-Yield Clinical Pearls for NEET-PG:** 1. **Standard DNS:** Contains 50g Dextrose per liter (5%) and 154 mEq/L of Na+ and Cl-. 2. **Maintenance Fluid (Holliday-Segar Formula):** 100/50/20 rule for pediatric fluid management. 3. **Isotonic Fluids:** Normal Saline (0.9%) and Ringer's Lactate are the fluids of choice for volume resuscitation, not dextrose-containing fluids. 4. **Hypoglycemia Risk:** Always monitor blood glucose when using concentrated dextrose solutions (>10%) via peripheral lines due to the risk of thrombophlebitis.

Q: What is the primary purpose of administering atropine as a preanesthetic medication?

To reduce bronchial secretions.. **Explanation:** Atropine is a competitive antagonist of acetylcholine at muscarinic receptors (an anticholinergic). In the context of preanesthetic medication, its primary purpose is to **reduce bronchial and salivary secretions** (antisialagogue effect). This is crucial because many anesthetic agents (like ketamine) and airway manipulations (like laryngoscopy) can trigger profuse secretions, which increase the risk of laryngospasm and interfere with airway visualization. * **Why Option B is Correct:** Atropine effectively dries up the respiratory tract mucosa. By reducing bronchial secretions, it maintains airway patency and prevents aspiration or obstruction during induction and emergence. * **Why Option A is Incorrect:** While atropine does reduce salivation, the "gag reflex" is a protective airway reflex mediated by the glossopharyngeal and vagus nerves. Atropine does not significantly suppress this reflex; topical anesthesia or deeper planes of general anesthesia are required for that. * **Why Option C is Incorrect:** Atropine causes **bronchodilation**, not bronchoconstriction. By blocking M3 receptors in the bronchial smooth muscle, it is actually beneficial for patients with reactive airway disease. * **Why Option D is Incorrect:** Atropine is a vagolytic drug that **causes tachycardia** (by blocking M2 receptors at the SA node). It is used to *treat* intraoperative bradycardia, not prevent tachycardia. **High-Yield NEET-PG Pearls:** * **Order of Potency (Antisialagogue):** Scopolamine > Glycopyrrolate > Atropine. * **Order of Potency (Tachycardia):** Atropine > Glycopyrrolate > Scopolamine. * **Glycopyrrolate** is often preferred over Atropine because it is a quaternary ammonium compound that does not cross the blood-brain barrier, avoiding central anticholinergic syndrome.

Q: Which of the following solutions is hypertonic?

3% normal saline. **Explanation:** The tonicity of an intravenous fluid is determined by its **osmolarity** relative to human plasma (normal range: **275–295 mOsm/L**). **1. Why 3% Normal Saline is Correct:** 3% Normal Saline (NaCl) is a **hypertonic** crystalloid. It contains 513 mEq/L of Sodium and 513 mEq/L of Chloride, resulting in a total osmolarity of **1026 mOsm/L**. Since this is significantly higher than plasma osmolarity, it causes water to shift from the intracellular space to the extracellular space. Clinically, it is used in the emergency management of symptomatic hyponatremia and to reduce intracranial pressure in neurosurgery. **2. Analysis of Incorrect Options:** * **5% Dextrose (D5W):** It is considered **isostatic/isotonic** in the bag (osmolarity ~252 mOsm/L). However, once infused, dextrose is rapidly metabolized, leaving behind free water, making it **physiologically hypotonic**. * **0.45% Normal Saline (Half-strength saline):** This is a **hypotonic** solution (osmolarity ~154 mOsm/L). It is used to treat cellular dehydration. * **0.9% Normal Saline:** This is the standard **isotonic** crystalloid (osmolarity ~308 mOsm/L). While slightly hyperosmolar compared to plasma, it does not cause significant fluid shifts across the cell membrane. **High-Yield Clinical Pearls for NEET-PG:** * **Ringer’s Lactate (RL):** The most physiological "balanced" salt solution (osmolarity ~273 mOsm/L). It is slightly **hypotonic**. * **Ideal Fluid for Brain Injury:** Avoid hypotonic fluids (like D5W or 0.45% NS) as they increase cerebral edema. Isotonic or hypertonic fluids are preferred. * **Rapid Correction Warning:** Rapid administration of hypertonic saline can lead to **Central Pontine Myelinolysis (Osmotic Demyelination Syndrome).**

Q: Which group of drugs, when used for premedication, produces a detached serenity without clouding of consciousness?

Ataractics. **Explanation:** The correct answer is **Ataractics** (Option C). **1. Why Ataractics is correct:** The term "Ataractic" is derived from the Greek word *ataraxia*, meaning "imperturbability" or "peace of mind." In anesthesiology, ataractics (commonly known as **Tranquilizers**) are drugs used for premedication to induce a state of **detached serenity**. The hallmark of these drugs is that they relieve anxiety and produce emotional calmness without causing significant sedation, hypnosis, or clouding of consciousness. Common examples include benzodiazepines (like Diazepam or Midazolam) and certain phenothiazines. **2. Why other options are incorrect:** * **Analeptics (Option A):** These are CNS stimulants (e.g., Doxapram). Instead of producing serenity, they increase alertness and are typically used to stimulate respiration or reverse CNS depression. * **Antiemetics (Option B):** These drugs (e.g., Ondansetron, Metoclopramide) are used to prevent postoperative nausea and vomiting (PONV). While some antiemetics (like Promethazine) have sedative properties, their primary mechanism is not the induction of "detached serenity." **3. High-Yield Clinical Pearls for NEET-PG:** * **Neuroleptanalgesia:** A state of quiescence, altered awareness, and analgesia produced by combining a neuroleptic (e.g., Droperidol) and an opioid (e.g., Fentanyl). * **Neuroleptanesthesia:** When the above is combined with Nitrous Oxide ($N_2O$) and Oxygen. * **Amnestic Effect:** Midazolam is the preferred ataractic for premedication due to its potent **anterograde amnesia** and rapid onset. * **Dissociative Anesthesia:** Distinct from ataractics, this is produced by **Ketamine**, where the patient appears awake but is unconscious and insensitive to pain.

Question 1

A 55-year-old woman requires an abdominoperineal operation for rectal cancer. She has a history of stable angina. Which of the following clinical markers is most likely to predict a cardiac event during her noncardiac surgery and should prompt further cardiac workup prior to her operation?

Accepted Answer

Unstable angina

Answer

Abnormal electrocardiogram

Answer

Prior stroke

Answer

Uncontrolled hypertension

Question 2

Which of the following is a primary goal of preanesthetic medication?

Accepted Answer

To mitigate the decrease in blood pressure.

Answer

To reduce the required dose of anesthetic agents.

Answer

To prevent aspiration of gastric contents.

Answer

To induce amnesia for peri-operative events.

Question 3

A 30-year-old female with a known history of lupus, who has been taking 20 mg of prednisolone daily since the age of 19, is scheduled for a myomectomy. What is your advice regarding perioperative steroid replacement?

Accepted Answer

Administer 20 mg of prednisolone on the morning of the procedure.

Answer

Stop steroids the night before the procedure.

Answer

Replace with 100 mg of hydrocortisone on the morning of the procedure.

Answer

Perform an adrenal function test prior to the procedure to decide on tapering the dose.

Question 4

When should prophylactic antibiotics be administered to a patient with rheumatic heart disease undergoing dental treatment?

Accepted Answer

1 hour before the procedure

Answer

3 hours before the procedure

Answer

7 days before the procedure

Answer

1 day before the procedure

Question 5

A staff nurse needs to prepare normal saline. How would she dilute a 10% Dextrose solution (per 100 ml) to achieve this?

Accepted Answer

80 ml 10% Dextrose with 20 ml Normal Saline

Answer

20 ml 10% Dextrose with 80 ml Normal Saline

Answer

60 ml 10% Dextrose with 40 ml Normal Saline

Answer

60 ml 10% Dextrose with 40 ml Normal Saline

Question 6

What is the primary purpose of administering atropine as a preanesthetic medication?

Accepted Answer

To reduce bronchial secretions.

Answer

To reduce salivation and the gag reflex.

Answer

To cause bronchoconstriction.

Answer

To prevent tachycardia.

Question 7

A 46-year-old obese female patient is scheduled for incisional hernia repair. She has a history of deranged liver functions within two weeks postoperatively after an abdominal mass surgery 12 years ago. Which of the following anesthetic agents is most commonly used for induction in patients with a history of liver dysfunction?

Accepted Answer

Desflurane

Answer

Halothane

Answer

Isoflurane

Answer

Sevoflurane

Question 8

Which of the following solutions is hypertonic?

Accepted Answer

3% normal saline

Answer

5% dextrose

Answer

0.45% normal saline

Answer

0.9% normal saline

Question 9

According to the American Society of Anesthesiologists (ASA) Physical Status Classification System, which description corresponds to Class III?

Accepted Answer

A patient with severe systemic disease that is not incapacitating

Answer

A normal healthy individual

Answer

A patient with mild systemic disease

Answer

None of the above

Question 10

Which group of drugs, when used for premedication, produces a detached serenity without clouding of consciousness?

Accepted Answer

Ataractics

Answer

Analeptics

Answer

Antiemetics

Answer

All of the above

Preoperative Evaluation and Management — MCQs

Preoperative Evaluation and Management — MCQs

On this page

Practice by Chapter

Want unlimited practice?