In the midazolam-PLR1-negative patients , there was no difference between the changes in the cardiac index induced by PLR1 ( PLR1 - cardiac function index [ CI ] ) and the changes in the cardiac index induced by PLR2 ( PLR2 - CI ) ( +1.4 % 7.4 % versus +1.7 % 6.4 % , P > 0.05 ) .