[Formulae to evaluate circulatory stability during anesthesia]

We analyzed anesthetic records to obtain formulae to evaluate circulatory stability during anesthesia. Eight anesthesiologists graded circulatory stability based on 67 consecutive anesthetic records. Median of the grade, on the maximum of 10 points, was determined as the criterion variables for multiple regression analysis. The explanatory variables were: age, weight, height, heart rate, anesthesia time and systolic as well as diastolic blood pressure. Interdependent parameters were not used for this analysis. Adequate numbers of the explanatory variables were determined when Akaike's information criterion (AIC) was minimal. Two different analytical methods were used. One of the most suitable formulae to express circulatory stability throughout anesthesia was: 9.28-0.012 x A-0.017 x SPmax + 0.013 x SPmin-0.009 x HRmax A: age (year) SPmax: maximal value in systolic blood pressure (mmHg) SPmin: minimal value in systolic blood pressure (mmHg) HRmax: maximal value in heart rate (bpm) We conclude that these formulae obtained are useful to evaluate circulatory stability during anesthesia.