Postoperative Care Practice Questions

Q: Post-anesthetic nausea and vomiting is uncommon with which of the following agents?

Propofol. **Explanation:** **Propofol** is the correct answer because it possesses unique **anti-emetic properties**. Unlike most anesthetic agents, propofol directly modulates the chemoreceptor trigger zone (CTZ) and decreases dopaminergic activity in the area postrema. It is considered the drug of choice for Total Intravenous Anesthesia (TIVA) specifically to reduce the incidence of Postoperative Nausea and Vomiting (PONV). **Analysis of Incorrect Options:** * **Halothane (Option B):** Inhalational agents (volatile anesthetics) are a primary risk factor for PONV. They trigger the vomiting center during the emergence phase of anesthesia. * **Fentanyl & Sufentanil (Options C & D):** These are potent opioids. Opioids are notorious for causing nausea and vomiting by increasing the sensitivity of the vestibular apparatus, delaying gastric emptying, and directly stimulating the CTZ in the medulla. **Clinical Pearls for NEET-PG:** * **Gold Standard for PONV Prophylaxis:** Propofol (TIVA) is the most effective anesthetic strategy to prevent PONV. * **Apfel Score:** A high-yield clinical tool used to predict PONV risk. Key risk factors include: Female gender, non-smoker status, history of motion sickness/PONV, and postoperative opioid use. * **Emetic Potential:** Nitrous oxide ($N_2O$) and Etomidate are also associated with a high incidence of PONV compared to Propofol. * **Management:** The first-line treatment for established PONV often includes 5-HT3 receptor antagonists (e.g., Ondansetron) or Dexamethasone.

Q: Post-operative vomiting is reduced and the patient is able to ambulate sooner with the use of which of the following agents?

Propofol. **Explanation** The correct answer is **Propofol**. **1. Why Propofol is Correct:** Propofol is the induction agent of choice for Day Care Surgery (Ambulatory Surgery) due to its unique pharmacological profile. It possesses potent **anti-emetic properties**, likely mediated through its action on the chemoreceptor trigger zone (CTZ) and subcortical pathways. By significantly reducing Post-Operative Nausea and Vomiting (PONV), it facilitates earlier oral intake and faster recovery. Furthermore, Propofol has a rapid onset and a very short context-sensitive half-life, leading to "clear-headed" recovery with minimal residual sedation, allowing patients to ambulate sooner. **2. Why Other Options are Incorrect:** * **Ketamine:** Known for causing emergence delirium, hallucinations, and vivid dreams. It does not have anti-emetic properties and may actually increase the risk of nausea. * **Enflurane:** Like most volatile inhalational anesthetics, Enflurane is a significant risk factor for PONV. It also has a slower elimination profile compared to modern agents like Sevoflurane or Desflurane, delaying discharge. * **Remifentanil:** While it is an ultra-short-acting opioid, all opioids are notorious for causing dose-dependent nausea and vomiting (PONV), which hinders early ambulation. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard for TIVA:** Propofol is the mainstay of Total Intravenous Anesthesia (TIVA). * **PONV Reduction:** Propofol is the only induction agent with intrinsic anti-emetic activity (sub-hypnotic doses of 10–20 mg can be used to treat refractory vomiting). * **Day Care Surgery:** The "ideal" anesthetic for day care should have rapid onset, rapid recovery, and minimal side effects (no PONV/shivering). Propofol fits this best. * **Mnemonic:** Propofol = **P**ost-op **P**eace (No vomiting, fast wake-up).

Q: Which of the following drugs is commonly used for post-anesthetic shivering?

Meperidine. **Explanation:** **Post-anesthetic shivering (PAS)** is a common complication occurring in up to 40% of patients recovering from general anesthesia. It is primarily caused by intraoperative hypothermia and the effects of anesthetic agents on thermoregulatory control. **Why Meperidine is the Correct Choice:** **Meperidine (Pethidine)** is considered the drug of choice for treating post-anesthetic shivering. Unlike other opioids, meperidine possesses unique **anti-shivering properties** mediated through its potent agonist activity at **$\kappa$ (kappa) opioid receptors** and its inhibitory effect on the $\alpha_2$-adrenoceptor. It effectively lowers the shivering threshold (the core temperature at which the body initiates shivering) more significantly than it lowers the vasoconstriction threshold, providing rapid relief. **Analysis of Incorrect Options:** * **B. Methylmorphine (Codeine):** This is a weak opioid primarily used as an antitussive or for mild pain; it has no significant effect on the thermoregulatory center. * **C. Methadone:** A long-acting $\mu$-opioid agonist used for chronic pain and opioid withdrawal; it lacks the specific $\kappa$-receptor profile required to suppress shivering effectively. * **D. Morphine:** While morphine is a potent analgesic, it acts primarily on $\mu$-receptors. It is significantly less effective than meperidine in treating PAS and requires much higher doses to achieve a similar effect, increasing the risk of respiratory depression. **High-Yield Clinical Pearls for NEET-PG:** * **Mechanism:** Meperidine reduces the shivering threshold via $\kappa$-receptors and $\alpha_2$ agonism. * **Dose:** A low intravenous dose (12.5–25 mg) is usually sufficient for PAS. * **Other Drugs:** Alpha-2 agonists (Clonidine, Dexmedetomidine) and Tramadol are also effective alternatives. * **Gold Standard Prevention:** Forced-air warming (Bair Hugger) is the most effective non-pharmacological method to prevent PAS.

Q: Which of the following drugs is believed to be effective in the treatment of postoperative shivering?

Pethidine. **Explanation:** **Postoperative Shivering (POS)** is a common complication following general or spinal anesthesia, occurring in up to 40% of patients. It increases oxygen consumption, CO2 production, and metabolic rate, which can be detrimental in patients with limited cardiac or respiratory reserve. **Why Pethidine is the Correct Answer:** Pethidine (Meperidine) is considered the **gold standard** and the most effective drug for treating postoperative shivering. Unlike other opioids, pethidine has unique **agonist activity at the κ (kappa) opioid receptors** and also inhibits the reuptake of serotonin and norepinephrine. These actions significantly lower the shivering threshold in the hypothalamus, effectively suppressing the thermoregulatory response more efficiently than pure μ-agonists like morphine or fentanyl. **Analysis of Incorrect Options:** * **Ondansetron (A):** While some studies suggest 5-HT3 antagonists may have a prophylactic role in preventing shivering by modulating central temperature regulation, they are not the primary treatment of choice once shivering has started. * **Diclofenac Sodium (B) & Paracetamol (D):** These are Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) and non-opioid analgesics. While excellent for postoperative pain management, they do not act on the central thermoregulatory mechanisms required to stop shivering. **Clinical Pearls for NEET-PG:** * **Mechanism of POS:** It is primarily caused by intraoperative core hypothermia and the "resetting" of the thermoregulatory threshold as anesthesia wears off. * **Dose of Pethidine:** A low dose (10–25 mg IV) is usually sufficient to stop shivering. * **Other Drugs:** Other agents used for prevention/treatment include **Tramadol**, **Clonidine**, and **Dexmedetomidine** (α2 agonists). * **Non-Pharmacological:** Forced-air warming (Bair Hugger) is the most effective way to prevent hypothermia intraoperatively.

Q: Postoperative shivering in the perioperative period is associated with what physiological change?

Increase in oxygen consumption. **Explanation:** Postoperative shivering (POS) is a common involuntary muscular activity occurring during recovery from general or regional anesthesia. It is primarily a thermoregulatory response to core hypothermia or the effects of anesthetic agents on the hypothalamus. **Why Option A is Correct:** Shivering involves intense, rhythmic skeletal muscle contractions. This metabolic activity significantly increases the body's demand for energy. Consequently, **oxygen consumption ($VO_2$) can increase by 200% to 500%**. This massive surge in oxygen demand can lead to hypoxemia, lactic acidosis, and increased carbon dioxide production, which is particularly dangerous in patients with limited cardiac or pulmonary reserve. **Why Other Options are Incorrect:** * **Option B:** Shivering triggers a **sympathetic nervous system surge**, leading to an *increase* in catecholamine release (norepinephrine and epinephrine), not a decrease. * **Option C:** Due to the sympathetic surge and increased metabolic demand, patients typically experience **tachycardia (increased heart rate) and hypertension (increased blood pressure)**. This increases myocardial oxygen demand and can precipitate myocardial ischemia or infarction in high-risk patients. **High-Yield Clinical Pearls for NEET-PG:** * **Mechanism:** Anesthetics cause peripheral vasodilation and inhibit the shivering threshold in the hypothalamus, leading to core-to-peripheral heat redistribution. * **Drug of Choice:** **Pethidine (Meperidine)** is the gold standard for treating postoperative shivering (dose: 10–25 mg IV). It acts on $\kappa$-opioid receptors to lower the shivering threshold. * **Other agents:** Clonidine, Tramadol, and Dexmedetomidine are also used for prevention and treatment. * **Complications:** Beyond metabolic stress, shivering increases intraocular and intracranial pressure and can cause wound dehiscence due to mechanical strain.

Q: A 63-year-old man with a 40-pack per year smoking history undergoes a low anterior resection for rectal cancer and on postoperative day 5 develops a fever, new infiltrate on chest x-ray, and leukocytosis. He is transferred to the ICU for treatment of his pneumonia because of clinical deterioration. Which of the following is a sign of early sepsis?

Peripheral vasodilation. **Explanation** The clinical presentation of fever, new pulmonary infiltrate, and leukocytosis in a postoperative patient suggests **Hospital-Acquired Pneumonia (HAP)** progressing to **Sepsis**. **1. Why Peripheral Vasodilation is Correct:** In the early stages of sepsis (often called **"Warm Shock"** or Hyperdynamic phase), the body releases inflammatory mediators (such as Nitric Oxide, Prostaglandins, and Cytokines). These mediators cause significant **peripheral vasodilation** and a decrease in systemic vascular resistance (SVR). To compensate for this drop in SVR and maintain tissue perfusion, the heart increases its rate and stroke volume, leading to a high cardiac output and warm, flushed extremities. **2. Why the Other Options are Incorrect:** * **Respiratory Acidosis:** Early sepsis typically presents with **Respiratory Alkalosis**. The inflammatory response and fever stimulate the respiratory center, causing tachypnea and "blowing off" CO₂, leading to a rise in pH. * **Decreased Cardiac Output:** This is a feature of **late sepsis** (Cold Shock) or cardiogenic shock. In early sepsis, the cardiac output is characteristically **increased** (Hyperdynamic state). * **Hypoglycemia:** Sepsis is a stress state that triggers the release of cortisol and catecholamines, which promote gluconeogenesis and glycogenolysis. Therefore, **hyperglycemia** (stress-induced) is the common finding. Hypoglycemia is rare and usually signifies hepatic failure or exhaustion of glycogen stores in end-stage sepsis. **Clinical Pearls for NEET-PG:** * **Hemodynamic Profile of Early Sepsis:** ↓ SVR, ↑ Cardiac Output, ↑ Mixed Venous Oxygen Saturation (SvO₂). * **qSOFA Score:** A quick bedside tool for sepsis—1. Altered mental status (GCS <15), 2. Systolic BP ≤100 mmHg, 3. Respiratory rate ≥22/min. * **Postoperative Fever (The 5 W's):** This patient (POD 5) fits the timeline for **W**ind (Pneumonia) or **W**ound (Infection).

Question 1

Post-anesthetic nausea and vomiting is uncommon with which of the following agents?

Accepted Answer

Propofol

Answer

Halothane

Answer

Fentanyl

Answer

Sufentanil

Question 2

Post-operative vomiting is reduced and the patient is able to ambulate sooner with the use of which of the following agents?

Accepted Answer

Propofol

Answer

Ketamine

Answer

Enflurane

Answer

Remifentanil

Question 3

Which of the following drugs is commonly used for post-anesthetic shivering?

Accepted Answer

Meperidine

Answer

Methylmorphine

Answer

Methadone

Answer

Morphine

Question 4

After undergoing a left pneumonectomy, a female patient has a chest tube in place for drainage. When caring for this patient, what is an essential nursing intervention?

Accepted Answer

Encourage coughing and deep breathing

Answer

Monitor fluctuations in the water-seal chamber

Answer

Clamp the chest tube once every shift

Answer

Milk the chest tube every 2 hours

Question 5

Which of the following drugs is believed to be effective in the treatment of postoperative shivering?

Accepted Answer

Pethidine

Answer

Ondansetron

Answer

Diclofenac sodium

Answer

Paracetamol

Question 6

Which drug is used for the postoperative reversal of muscular paralysis?

Accepted Answer

Neostigmine

Answer

Pyridostigmine

Answer

Physostigmine

Answer

D-tubocurarine

Question 7

Postoperative shivering is treated with which of the following?

Accepted Answer

Pethidine

Answer

Diazepam

Answer

Antihistaminics

Answer

Anticholinergics

Question 8

Which drug worsens post-cardiothoracic surgery delirium?

Accepted Answer

Anticholinergic agents

Answer

Antipsychotics

Answer

Benzodiazepines

Answer

Antihistamines

Question 9

Postoperative shivering in the perioperative period is associated with what physiological change?

Accepted Answer

Increase in oxygen consumption

Answer

Decreased catecholamine release

Answer

Decreased heart rate and blood pressure

Answer

All of the above

Question 10

A 63-year-old man with a 40-pack per year smoking history undergoes a low anterior resection for rectal cancer and on postoperative day 5 develops a fever, new infiltrate on chest x-ray, and leukocytosis. He is transferred to the ICU for treatment of his pneumonia because of clinical deterioration. Which of the following is a sign of early sepsis?

Accepted Answer

Peripheral vasodilation

Answer

Respiratory acidosis

Answer

Decreased cardiac output

Answer

Hypoglycemia

Postoperative Care — MCQs

Postoperative Care — MCQs

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