In hypotensive patients, Induction of anaesthesia should be done with:
First, the core concept here is choosing the right anesthetic agent for hypotensive patients. The key is to avoid drugs that could further lower blood pressure. Agents that cause vasodilation or myocardial depression should be avoided. Common anesthetic agents include propofol, etomidate, ketamine, and thiopental.
Propofol is known for causing hypotension due to its vasodilatory effects and myocardial depression. Thiopental also has similar effects. Etomidate, on the other hand, is preferred in hypotensive patients because it has minimal cardiovascular effects. Ketamine is a bit of a paradox; it can increase blood pressure by increasing sympathetic activity but might not be ideal in all hypotensive cases, especially if the hypotension is due to hypovolemia.
So the correct answer is likely etomidate. The incorrect options would be propofol, thiopental, and maybe ketamine. I need to explain why each of these is wrong. Propofol and thiopental cause hypotension, ketamine's effects might be contraindicated in certain scenarios. The clinical pearl here is that etomidate is the drug of choice in unstable patients due to its hemodynamic stability. I should make sure the explanation is concise and fits within the character limit. Let me structure this step by step as per the user's instructions.
**Core Concept**
The question tests knowledge of anesthetic agent selection in hypotensive patients. The goal is to minimize cardiovascular depression during induction, prioritizing agents with minimal hemodynamic impact. Key agents include etomidate, which preserves myocardial function and systemic vascular resistance.
**Why the Correct Answer is Right**
Etomidate is preferred for hypotensive patients because it has minimal negative inotropic effects and maintains systemic vascular resistance. It avoids significant myocardial depression or vasodilation, making it safer in hemodynamically unstable individuals. Its mechanism involves GABA-A receptor activation without causing profound hypotension, unlike other agents.
**Why Each Wrong Option is Incorrect**
**Option A:** Propofol causes dose-dependent hypotension due to vasodilation and myocardial depression. **Option B:** Thiopental induces hypotension by reducing systemic vascular resistance and cardiac output. **Option C:** Ketamine may increase blood pressure via sympathetic activation but can worsen hypotension in hypovolemic patients and is not ideal for unstable hemodynamics.
**Clinical Pearl / High-Yield Fact**
Etomidate is the **drug of choice for anesthetic induction in hemodynamically unstable patients**. Remember: "Etomidate = no hype, no drop"—it avoids extreme hemodynamic fluctuations compared to propofol or thiopental.
**Correct Answer: C. Etomidate**