Effect of intravenous injection of dopamine on the bispectral index,entropy index,and sedation score during continuous propofol infusion

Objective To examine the effect of an intravenous injection of dopamine on the bispectral index(BIS),entropy index,and sedation score [Observer’s Assessment of Alertness/Sedation(OAAS)] during continuous propofol infusion.Methods The present study selected nine patients undergoing an operation under ASA Ⅰ-Ⅱ general anesthesia.Propofol is administered for anesthesia,and plasma/effective concentration(Cp/Ce) remained unchanged when OAA/S=2.An intravenous injection of dopamine is then administrated at a single injection dosage of 3 mg to 5 mg.BIS,response entropy(RE),state entropy(SE),OAA/S score,and mean arterial pressure(MAP) are recorded 1 min before injection and 1 min to 5 min after injection.Results Cp/Ce is 1.71±0.42 when OAA/S=2.After the intravenous injection of dopamine,BIS increases remarkably in five cases(BIS > 70 in four cases).The increment primarily occurs at 3 and 4 min.The entropy index in nine cases begins to increase at 2min,with this index apparently higher than that before the injection in six cases.The difference between RE and SE increases,and the increment of BIS and the entropy index occurs later than MAP.The OAA/S score ≥4 in five cases.Conclusion Intravenous injection of dopamine results in higher BIS,entropy index,and sedation score during a continuous infusion of propofol when OAA/S=2,thereby having an arousal effect.The entropy index is sensitive in terms of reflecting the arousal effect of dopamine.