Ketamine's cardiovascular effects are primarily due to which mechanism?

Ketamine's cardiovascular effects are primarily due to which mechanism?

• A. Increased SNS Tone Leading to Increases in SVR, HR, and CO
• B. Direct Myocardial Depression
• C. Decreased SVR
• D. Decreased CO

Answer: (A)

Ketamine’s cardiovascular effects mainly arise from activating the sympathetic nervous system. It increases sympathetic outflow and catecholamine release, which raises vascular tone (increasing systemic vascular resistance) and stimulates beta-adrenergic receptors in the heart, boosting heart rate and contractility. The combined result is higher cardiac output with preserved or increased afterload. This makes direct myocardial depression unlikely as the primary mechanism. Decreased systemic vascular resistance or decreased cardiac output would not explain the usual ketamine response in healthy patients.

Ketamine’s cardiovascular effects mainly arise from activating the sympathetic nervous system. It increases sympathetic outflow and catecholamine release, which raises vascular tone (increasing systemic vascular resistance) and stimulates beta-adrenergic receptors in the heart, boosting heart rate and contractility. The combined result is higher cardiac output with preserved or increased afterload. This makes direct myocardial depression unlikely as the primary mechanism. Decreased systemic vascular resistance or decreased cardiac output would not explain the usual ketamine response in healthy patients.