Closed-loop norepinephrine infusion reduces postoperative hypotension after cardiac surgery: Study

France: In a new study it was found that in patients admitted to the ICU following cardiac surgery, closed-loop management of norepinephrine infusion considerably reduces postoperative hypotension compared to manual control. This study was conducted by Olivier Desebbe & team, findings of which were published in the journal Anesthesia and Analgesia.

Vasopressors are essential in the treatment of vasodilatory hypotension. Currently, vasopressor infusions are manually regulated to attain a set arterial pressure target. Researchers created a closed-loop vasopressor (CLV) controller in this study to assist treat hypotension more effectively during the perioperative phase. They evaluated the hypothesis that patients treated with such a system would have less hypotension than those treated with standard care.

For this study, a 2-hour trial period, 40 patients hospitalized to the intensive care unit (ICU) following heart surgery were randomly assigned to one of two groups. The goal for all patients was to keep their mean arterial pressure (MAP) between 65 and 75 mm Hg by utilizing norepinephrine. The norepinephrine infusion in the CLV group was managed by the CLV system; in the control group, it was changed manually by the ICU nurse. Fluid administration in both groups was standardized by employing an aided fluid management system coupled to an advanced hemodynamic monitoring system. The primary outcome was the proportion of time patients were hypotensive, defined as having a MAP of less than 65 mm Hg, during the trial period.

The key findings are as follow:

1. The proportion of time spent with hypotension was considerably lower in the CLV group than in the control group over the 2-hour study period.

2. The CLV group also had a higher percentage of time with MAP between 65 and 75 mm Hg.

3. The proportion of time with a MAP greater than 75 mm Hg (and norepinephrine still being injected) was also considerably lower in the CLV group compared to the control group.

4. The number of norepinephrine infusion rate changes in the CLV group was larger than in the control group over the research period.

5. Neither group experienced any adverse events during the trial period.

Reference:

Desebbe O, Rinehart J, Van der Linden P, Cannesson M, Delannoy B, Vigneron M, Curtil A, Hautin E, Vincent JL, Duranteau J, Joosten A. Control of Postoperative Hypotension Using a Closed-Loop System for Norepinephrine Infusion in Patients After Cardiac Surgery: A Randomized Trial. Anesth Analg. 2022 Jan 21. doi:10.1213/ANE.0000000000005888.