WBR0537
| Author | [[PageAuthor::Rim Halaby, M.D. [1], Alison Leibowitz [2] (Reviewed by Alison Leibowitz)]] |
|---|---|
| Exam Type | ExamType::USMLE Step 1 |
| Main Category | MainCategory::Pharmacology |
| Sub Category | SubCategory::Neurology |
| Prompt | [[Prompt::A researcher, studying the hemodynamic and respiratory effects of intravenous anesthetics, injects a mouse with intravenous ketamine infusion. Several minutes later, he measures the mouse's heart rate (HR), blood pressure (BP), cerebral blood flow (CBF), and bronchial diameter (BDm) to assess the cardiovascular and respiratory roles of ketamine. Which of the following hemodynamic and respiratory changes are most likely to occur following ketamine infusion in this experiment?]] |
| Answer A | AnswerA::Increased HR, increased BP, increased CBF, and increased BDm |
| Answer A Explanation | AnswerAExp::See overall explanation. |
| Answer B | AnswerB::Increased HR, decreased BP, increased CBF, and increased BDm |
| Answer B Explanation | [[AnswerBExp::BP frequently increases following ketamine infusion.]] |
| Answer C | AnswerC::Increased HR, decreased BP, increased CBF, and decreased BDm |
| Answer C Explanation | [[AnswerCExp::BP and BDm frequently increase following ketamine infusion.]] |
| Answer D | AnswerD::Increased HR, decreased BP, decreased CBF, and decreased BDm |
| Answer D Explanation | [[AnswerDExp::BP, CBF, and BDm frequently increase following ketamine infusion.]] |
| Answer E | AnswerE::Decreased HR, increased BP, increased CBF, and increased BDm |
| Answer E Explanation | [[AnswerEExp::HR frequently increases following ketamine infusion.]] |
| Right Answer | RightAnswer::A |
| Explanation | [[Explanation::Ketamine, a PCP analog used as an intravenous anesthetic drug, acts as a non-competitive NMDA receptor blocker. A side effect of ketamine is dissociative anesthesia, a state of profound analgesia with only superficial sleep and spontaneous ventilation. It does not usually suppress respiratory drive unless used at very high doses.
Because ketamine increases intracranial pressure, it is contraindicated in patients with brain injury. Following ketamine administration, frequently there is an increase in heart rate, blood pressure, CVP, CO2 baroreceptor function, bronchodilation, respiratory rate, uterine tone, and salivation. |
| Approved | Approved::Yes |
| Keyword | WBRKeyword::ketamine, WBRKeyword::systemic effect, WBRKeyword::hemodynamic, WBRKeyword::respiratory, WBRKeyword::adverse drug reaction, WBRKeyword::dissociative analgesia, WBRKeyword::heart rate, WBRKeyword::cerebral blood flow, WBRKeyword::bronchial, WBRKeyword::side effects, WBRKeyword::intravenous, WBRKeyword::trial |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |