In the buffered crystalloid group , @ of @ patients ( @ % ) developed AKI within @ days after enrollment compared with @ of @ patients ( @ % ) in the saline group ( absolute difference , @ % -LSB- @ % CI , -@ % to @ % -RSB- ; relative risk -LSB- RR -RSB- , @ -LSB- @ % CI , @ to @ -RSB- ; P = @ ) .