Anesthesia for Gastrointestinal Endoscopy — MCQs
What does a pulse oximeter primarily measure?
Which drug is commonly used for emergency intubation?
A 32-year-old male is a known hypertensive and is being planned for cholecystectomy. Which of the following anesthetic agents is contraindicated in this person?
As per the latest NRP guidelines, what is the target preductal saturation after birth at 5 minutes?
Steps in review of patient's history during secondary survey of trauma care can be summarised as
Which of the following is not a known complication associated with the procedure done in the patient?
What is the most reliable indicator to prevent esophageal intubation?
Which one of the following is the investigation of choice in a patient with haematemesis?
Which of the following is used for day care surgery?
What effect does Propofol have on the EEG?
Anesthesia for Gastrointestinal Endoscopy Indian Medical PG Practice Questions and MCQs
Question 1: What does a pulse oximeter primarily measure?
- A. Oxygen content of blood
- B. Oxygen saturation (Correct Answer)
- C. Partial pressure of oxygen
- D. Carbon dioxide levels
Explanation: ***Oxygen saturation*** - A pulse oximeter primarily measures the **percentage of hemoglobin** in arterial blood that is saturated with oxygen. - This is often reported as **SpO2** (peripheral oxygen saturation), an estimate of SaO2 (arterial oxygen saturation). *Oxygen content of blood* - The **total amount of oxygen** in the blood includes dissolved oxygen and oxygen bound to hemoglobin. - Pulse oximeters only measure the proportion of hemoglobin bound to oxygen, not the absolute amount of oxygen. *Partial pressure of oxygen* - This refers to the **amount of oxygen dissolved in the plasma** and is denoted as PaO2. - Measurement of PaO2 requires an **arterial blood gas (ABG)** analysis, which is an invasive procedure. *Carbon dioxide levels* - Pulse oximeters do **not measure CO2**; they use light absorption at specific wavelengths to differentiate oxyhemoglobin from deoxyhemoglobin. - Measurement of carbon dioxide requires **capnography** or arterial blood gas analysis.
Question 2: Which drug is commonly used for emergency intubation?
- A. None of the options
- B. Etomidate (Correct Answer)
- C. Propofol
- D. Ketamine
Explanation: ***Etomidate*** - Etomidate is a **short-acting nonbenzodiazepine hypnotic** often preferred for rapid sequence intubation (RSI) due to its minimal impact on **hemodynamic stability**. - It induces **rapid unconsciousness** with a quick onset and offset, making it suitable for emergency airway management in patients who are hemodynamically compromised. *Propofol* - Propofol is a **potent intravenous anesthetic** that can cause significant **hypotension** due to vasodilation and myocardial depression. - While it provides rapid onset of sedation and amnesia, its cardiovascular side effects make it less ideal for patients with **unstable hemodynamics** during emergency intubation. *Ketamine* - Ketamine is a **dissociative anesthetic** that causes a cataleptic state, amnesia, and analgesia, often leading to **bronchodilation** and cardiovascular stimulation. - While useful in patients with **reactive airway disease** or hypotension, it can increase intracranial pressure and may induce sympathetic stimulation, which might not be ideal for all emergency intubation scenarios. *None of the options* - This option is incorrect because **Etomidate is a commonly used drug** for emergency intubation, particularly where hemodynamic stability is a concern. - Other agents are also used but Etomidate is a clear clinical choice in many situations.
Question 3: A 32-year-old male is a known hypertensive and is being planned for cholecystectomy. Which of the following anesthetic agents is contraindicated in this person?
- A. Etomidate
- B. Propofol
- C. Ketamine (Correct Answer)
- D. Midazolam
Explanation: ***Ketamine*** - **Ketamine** can cause significant increases in **heart rate** and **blood pressure**, which are undesirable in a hypertensive patient undergoing surgery. - Its **sympathomimetic effects** can exacerbate pre-existing hypertension and increase the risk of perioperative cardiovascular complications. *Etomidate* - **Etomidate** is known for its **cardiovascular stability**, making it a good choice for hypertensive patients as it has minimal effects on heart rate and blood pressure. - It can, however, suppress adrenal steroid synthesis, which is generally not a contraindication for a single dose in a healthy hypertensive patient. *Propofol* - **Propofol** often causes a **dose-dependent decrease in blood pressure** due to vasodilation and myocardial depression. - While this can be a concern, it is usually managed by careful titration and is less likely to exacerbate hypertension than ketamine. *Midazolam* - **Midazolam** is a benzodiazepine that provides **sedation and anxiolysis**; it has minimal effects on hemodynamics at typical anesthetic induction doses. - It is often used as a co-induction agent, not as a primary induction agent, and generally does not worsen hypertension.
Question 4: As per the latest NRP guidelines, what is the target preductal saturation after birth at 5 minutes?
- A. 65% - 70%
- B. 75% - 85%
- C. 85% - 95%
- D. 80% - 85% (Correct Answer)
Explanation: ***80% - 85%*** - The Neonatal Resuscitation Program (NRP) guidelines recommend target pulse oximetry readings for **preductal oxygen saturation** in newborns. - At **5 minutes after birth**, the expected preductal saturation range is **80% - 85%**. - This represents the specific target for the 5-minute mark according to current NRP guidelines. *65% - 70%* - This range is the target for **2 minutes after birth**, reflecting the early transition from fetal circulation. - It is **too low** for the target saturation at 5 minutes post-delivery according to NRP. *75% - 85%* - This range is **too broad** and spans multiple time points (3-5 minutes). - The lower end (75%) represents the target at **3 minutes**, while 80-85% is specifically for **5 minutes**. - NRP guidelines specify **80-85%** as the precise target range for 5 minutes, not 75-85%. - This option is incorrect because it does not reflect the **specific** 5-minute target. *85% - 95%* - This higher range is the target for **10 minutes after birth**, indicating the near-complete transition to extrauterine circulation. - It is **too high** for the expected preductal saturation at 5 minutes according to current NRP guidelines.
Question 5: Steps in review of patient's history during secondary survey of trauma care can be summarised as
- A. TRIAGE
- B. ABCDE
- C. AMPLE (Correct Answer)
- D. None of the options
Explanation: ***AMPLE*** - The **AMPLE history** is a mnemonic used during the **secondary survey** in trauma care to gather crucial patient information - It stands for **Allergies, Medications, Past medical history/Pregnancy, Last meal, and Events** surrounding the injury. *TRIAGE* - **Triage** is the process of prioritizing patients based on the severity of their condition and the likelihood of benefit from immediate treatment. - It is an initial assessment done to determine the urgency of care, not a detailed historical review for a single patient. *ABCDE* - The **ABCDE approach** (**Airway, Breathing, Circulation, Disability, Exposure**) is part of the **primary survey** in trauma care. - It focuses on identifying and managing immediate life-threatening conditions. *None of the options* - This option is incorrect because **AMPLE** specifically describes the historical review process during the secondary survey.
Question 6: Which of the following is not a known complication associated with the procedure done in the patient?
- A. Aspiration
- B. Pneumothorax
- C. Refeeding (Correct Answer)
- D. Arrhythmia
Explanation: ***Refeeding*** - The image shows a **central venous catheter (CVC)**, likely in the internal jugular vein. While CVCs are used for administering nutrition such as **total parenteral nutrition (TPN)**, refeeding syndrome is a metabolic complication that occurs when nutrition is reintroduced too quickly in severely malnourished patients. - **Refeeding syndrome is NOT a direct complication of the CVC insertion procedure itself**—it is a systemic metabolic complication related to the nutritional intervention (characterized by severe shifts in fluids and electrolytes, particularly hypophosphatemia, hypokalemia, and hypomagnesemia). - Therefore, refeeding is **not associated with the procedure** of CVC insertion. *Pneumothorax* - **Pneumothorax** is a well-recognized mechanical complication of central venous catheterization, particularly with subclavian and internal jugular vein approaches. - Occurs due to accidental puncture of the **pleura** during needle insertion, allowing air to enter the pleural space and causing lung collapse. - Incidence ranges from 1-6% depending on the site and operator experience. *Arrhythmia* - **Cardiac arrhythmias** are a known complication during CVC insertion when the guidewire or catheter tip inadvertently advances too far into the heart chambers (right atrium or ventricle). - Mechanical irritation of the myocardium can trigger **premature ventricular contractions (PVCs)** or other arrhythmias. - Usually transient and resolve upon withdrawing the catheter to proper position. *Aspiration* - While **aspiration** can occur in critically ill patients who require CVCs (due to altered consciousness, dysphagia, or ventilator-associated issues), it is **not a direct mechanical complication of the CVC insertion procedure itself**. - Aspiration relates to patient condition rather than the catheter placement technique, though both may coexist in the same clinical scenario.
Question 7: What is the most reliable indicator to prevent esophageal intubation?
- A. Oxygen saturation on pulse oximeter
- B. Direct visualization of passing tube beneath vocal cords
- C. Auscultation over chest
- D. Measurement of CO2 in exhaled air (EtCO2). (Correct Answer)
Explanation: ***Measurement of CO2 in exhaled air (EtCO2)*** - The presence of **carbon dioxide** in exhaled air confirms tracheal intubation as the esophagus does not contain CO2. - This method provides a **real-time**, objective assessment of tube placement that is highly reliable because even small amounts of CO2 are detected. *Oxygen saturation on pulse oximeter* - This indicator measures **oxygenation**, which can remain adequate for several minutes after esophageal intubation due to pre-oxygenation. - A **delayed drop in saturation** might indicate esophageal intubation, but it's not immediate and therefore not the most reliable early indicator. *Direct visualization of passing tube beneath vocal cords* - While helpful, **direct visualization** can sometimes be misleading due to difficult airways or poor visibility, where the tube might appear to pass correctly but enter the esophagus. - This method is **operator-dependent** and its reliability can vary based on the intubator's experience and the patient's anatomy. *Auscultation over chest* - **Auscultation** can detect breath sounds; however, sounds can be transmitted from the stomach or surrounding tissues, leading to false positives. - It is also very difficult to reliably distinguish between **esophageal and tracheal sounds**, especially in noisy environments or with inexperienced personnel, making it less reliable than EtCO2.
Question 8: Which one of the following is the investigation of choice in a patient with haematemesis?
- A. Flexible upper gastrointestinal endoscopy (Correct Answer)
- B. Contrast enhanced CT scan
- C. Barium meal for stomach and duodenum
- D. Selective left gastric angiography
Explanation: ***Flexible upper gastrointestinal endoscopy*** - This is the **investigation of choice** for haematemesis as it allows for direct visualization of the upper gastrointestinal tract to identify the source of bleeding [1]. - It also enables **therapeutic intervention**, such as injection sclerotherapy, banding, or clip application, to stop the bleeding [1]. *Contrast enhanced CT scan* - A CT scan is generally **not the primary investigation** for acute haematemesis because it offers less diagnostic accuracy for mucosal lesions and cannot provide therapeutic intervention [1]. - While it can identify large bleeds or structural abnormalities, it is **less sensitive for smaller bleeds** or subtle mucosal abnormalities compared to endoscopy. *Barium meal for stomach and duodenum* - A barium meal is **contraindicated in acute gastrointestinal bleeding** as the barium can obscure endoscopic views and interfere with subsequent attempts at endoscopy or angiography [1]. - It provides **limited diagnostic information** about the active bleeding site and offers no therapeutic capabilities. *Selective left gastric angiography* - Angiography is typically reserved for cases of **severe, persistent bleeding** where endoscopy has failed to locate or control the bleed. - It is an **invasive procedure** with potential complications and is not indicated as the initial diagnostic investigation.
Question 9: Which of the following is used for day care surgery?
- A. Thiopentone
- B. Ketamine
- C. Etomidate
- D. Propofol (Correct Answer)
Explanation: ***Propofol*** - **Propofol** is favored for **day care surgery** due to its **rapid onset** and **rapid recovery** profile, allowing patients to be discharged quickly. - It produces a **clear-headed recovery** with less postoperative nausea and vomiting compared to other agents. *Thiopentone* - **Thiopentone** has a **longer recovery time** and greater potential for **postoperative sedation** and **nausea**, making it less suitable for day care surgery. - Its use often leads to a **delayed discharge** from the recovery unit. *Ketamine* - **Ketamine** can cause **psychomimetic effects** (e.g., hallucinations, vivid dreams) and **delirium** during emergence, which are undesirable for day care procedures. - It also leads to **increased heart rate** and **blood pressure**, which may prolong recovery and observation time. *Etomidate* - **Etomidate** is known to cause **adrenocortical suppression** and can be associated with **pain on injection** and **myoclonus**, which are not ideal for routine day care use. - While it has a relatively **stable cardiovascular profile**, these side effects limit its widespread use in short procedures where rapid, smooth recovery is paramount.
Question 10: What effect does Propofol have on the EEG?
- A. Causes no significant change in EEG
- B. Causes EEG activation
- C. Induces EEG depression (Correct Answer)
- D. None of the options
Explanation: ***Induces EEG depression*** - Propofol, an intravenous anesthetic, primarily acts as a **GABA-A receptor agonist**, enhancing inhibitory neurotransmission in the brain. - This leads to a dose-dependent reduction in brain electrical activity, characterized by a decrease in the **amplitude and frequency of EEG waves**, effectively causing EEG depression. *Causes no significant change in EEG* - This statement is incorrect because propofol has profound effects on brain electrical activity, as measured by the EEG. - Its anesthetic properties are directly linked to its ability to alter neuronal excitability significantly. *Causes EEG activation* - EEG activation typically involves an increase in fast-frequency, low-amplitude waves, often associated with states of arousal or epileptic activity. - Propofol's primary effect is to depress brain activity, which is the opposite of activation. *None of the options* - This option is incorrect because propofol has a well-documented and significant effect on the EEG, which is precisely EEG depression.
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