NORepinephrine-Maintaining-individuaALIZEd Blood Pressure

Overview

This study compares the effect of individualized vs standard blood pressure management on postoperative myocardial injury in high-risk patients undergoing non-cardiac surgery by measuring the hs-cTnT levels. Continuous norepinephrine infusion is used to target a mean pressure of greater than 65mmHg and a systolic pressure less than 160mmHg in the standardized group while the target is 20% within the ward blood pressure in the individualized group. The pre- and postoperative hs-cTnT levels to detect myocardial injury are compared between the two groups.

Managing the blood pressure preoperatively is important in high-risk patients because hypotension can lead to perioperative myocardial injury. It has been reported that a systolic pressure of less than 50-55mmHg or greater than 40% decrease can lead to cardiac complications. The mechanism of hypotension leading to postoperative myocardial injury is due to hypoperfusion and ischemic reperfusion injury. In this randomized controlled study, the blood pressure for participants in the standardized group is maintained as follows: mean blood pressure greater than 65mmHg and systolic blood pressure less than 160mmHg. The individualized group participants' blood pressure is maintained at a target of 20% within the preoperative ward blood pressure. Anesthesia and intraoperative management are the same in both groups to target a bispectral index level of 50. In order to quantitatively measure the myocardial injury, high sensitive cardiac troponin T (hs-cTnT) will be measured pre- and postoperatively. A level greater than 14ng/dl has been reported to be associated with myocardial injury and mortality. The objective of this study is to show that the standardized protocol of maintaining a mean pressure greater than 65mmHg is non inferior to the individualized management in terms of postoperative myocardial injury.