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Thursday, February 25, 2016

VASOACTIVE AGENTS; DO YOU KNOW ?

Evidence suggests that dopamine can produce mild cerebral vasodilatation.

Phenylephrine can be the drug of choice when the cardiac index (CI) is sufficient but MAP is below the goal

Dobutamine does not have any dopaminergic agonist action.

In case of Labetalol, a reduction in MAP usually occurs when the dose is sufficient to decrease HR

propanolol shifts the hemoglobin-oxygen dissociation curve to the right.

Milrinone can induce thrombocytopenia as well as hypotension.

SNP is associated with the activation of the renin-angiotensin system ; reflex tachycardia can interfere with blood pressure reduction.

Occasionally, patients demonstrate relative resistance to SNP and they are at particular risk for developing cyanide toxicity.

SNP causes more arteriolar than venular vasodilatation, while NTG causes more venular than arteriolar vasodilatation.

Vasopressin increases arterial tone ; it is administered as a constant infusion, and not titrated up to avoid severe complications of distal ischemia.

Reference: Newfield, Philippa; Cottrell, James E., Handbook of Neuroanesthesia, 4th Edition