Ans. is 'b' i.e., Etomidate Effects of Etomidate on cardiovascular systemEtomidate has minimal effects on the cardiovascular system.It causes mild reduction in peripheral vascular resistance which may cause a slight decline in arterial blood pressure.Myocardial contractility and cardiac output are usually unchanged. Etomidate does not release histamine. Cardiovascular effect of Propofol:The major cardiovascular effect of propofol is a decrease in arterial blood pressure due to a drop in systemic vascular resistance (inhibition of sympathetic vasoconstrictor activity, cardiac contractility and preload).Propofol markedly impairs the normal arterial baroreflex response to hypotension. Sometimes there may be a marked drop in preload.Cardiovascular effect of barbiturates (Thiopental)The cardiovascular effect of barbiturates vary markedly depending on the volume status, bas line autonomic tone and preexisting cardiovascular disease.Normally, intravenously administered barbiturates cause a fall in blood pressure.Cardiac output is maintained due to increase in heart rate and increased myocardial contractility from compensatory baroreceptor reflexes.However, in the absence of adequate baroreceptor response (e.g., hypovolemia, congestive heart failure, b adrenergic blockade) cardiac output and arterial blood pressure may fall dramatically due to uncompensated pooling and unmasked direct myocardial depression.Effect of ketamine on cardiovascular systemKetamine causes central stimulation of sympathetic system which causes increased arterial blood pressure, heart rate and cardiac output. There is also increase in pulmonary artery pressure and myocardial work.Because of these effects, ketamine should be avoided in patients with coronary artery disease, uncontrolled hypertension, congestive heart failure and arterial aneurysms.