WBR0537
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| Author | [[PageAuthor::Rim Halaby, M.D. [1] (Reviewed by Serge Korjian M.D.)]] |
|---|---|
| Exam Type | ExamType::USMLE Step 1 |
| Main Category | MainCategory::Pharmacology |
| Sub Category | SubCategory::Neurology |
| Prompt | [[Prompt::A researcher is studying the hemodynamic and respiratory effects of intravenous anesthetics. In one experiment, he 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::Ketamine administration results in increased HR, increased BP, increased CBF, and increased BDm. |
| Answer B | AnswerB::Increased HR, decreased BP, increased CBF, and increased BDm |
| Answer B Explanation | AnswerBExp::BP increases following ketamine infusion. |
| Answer C | AnswerC::Increased HR, decreased BP, increased CBF, and decreased BDm |
| Answer C Explanation | AnswerCExp::BP and BDm increase following ketamine infusion. |
| Answer D | AnswerD::Increased HR, decreased BP, decreased CBF, and decreased BDm |
| Answer D Explanation | AnswerDExp::BP, CBF, and BDm increase following ketamine infusion. |
| Answer E | AnswerE::Decreased HR, increased BP, increased CBF, and increased BDm |
| Answer E Explanation | AnswerEExp::HR increases following ketamine infusion. |
| Right Answer | RightAnswer::A |
| Explanation | [[Explanation::Ketamine is a phencyclidine (PCP) analog used as an intravenous anesthetic drug. Ketamine acts as a non-competitive N-methyl-D-aspartate (NMDA) receptor blocker. Ketamine is known to cause 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 among patients with brain injury. Other systemic effects of ketamine are generally also increased. Following ketamine, there is an increased heart rate, blood pressure, CVP, CO2 baroreceptor function, bronchodilation, respiratory rate, uterine tone, salivation. |
| Approved | Approved::Yes |
| Keyword | WBRKeyword::Ketamine, WBRKeyword::Hemodynamic, WBRKeyword::Respiratory, WBRKeyword::Adverse effect, WBRKeyword::Drug, WBRKeyword::Anesthesia, WBRKeyword::Dissociative, WBRKeyword::Analgesia, WBRKeyword::Heart rate, WBRKeyword::Cerebral blood flow, WBRKeyword::CVP, WBRKeyword::Bronchodilation, WBRKeyword::Respiratory rate, WBRKeyword::Uterine tone, WBRKeyword::Salivation |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |