Determination of the standard value of circulating blood volume during anesthesia using pulse dye-densitometry: a multicenter study in Japan.

PURPOSE: The standard value for circulating blood volume (BV) during anesthesia was determined by a multicenter study in Japan. The significance of BV on the reduction of blood pressure after the induction of anesthesia was also examined. METHODS: The study included 184 patients from eight university hospitals. After the induction of anesthesia, pulse dye-densitometry was performed according to a uniform protocol. Factors contributing to reduced blood pressure after induction of anesthesia were examined by multiple logistic regression analysis. RESULTS: The mean and standard deviation of BV was 80.0 +/- 13.9 ml x kg(-1); for females and 84.2 +/- 15.3 ml x kg(-1) for males (P > 0.05). There was no age difference in terms of BV. After adjusting for the effects of height, weight, and age, the factors predisposing to a reduction in blood pressure of >20 mmHg after induction of anesthesia were found to be age (P < 0.01) and BV (ml x kg(-1)) (P < 0.001). CONCLUSION: We determined the BV of anesthetized patients before surgery in Japan using pulse dye-densitometry. It is suggested that age is not a factor regarding BV, and that blood pressure tends to be reduced in hypovolemic patients after induction of anesthesia.