Prognostic performance of the ratio of mean arterial pressure to norepinephrine equivalent dose in critically ill hypotensive patients: A single-center retrospective cohort study.

BACKGROUND

The ratio of mean arterial pressure (MAP) to norepinephrine equivalent dose (NED) may better quantify the degree of hemodynamic instability by incorporating both patient response and intervention intensity.

OBJECTIVES

To evaluate the prognostic performance of the MAP/NED ratio for mortality.

METHODS

This single-center retrospective cohort study consecutively included adult critically ill hypotensive patients who received norepinephrine infusion of at least 5 μg/min (in base formulation) within the first 24 h of intensive care unit (ICU) stay. The exposure of interest was the lowest MAP/NED ratio during the initial 24 h. The primary outcome was hospital mortality. We assessed the predictive validity of the lowest MAP/NED ratio for hospital mortality using logistic regression and area under the receiver operating characteristic curve (AUC). We compared the AUC of the lowest MAP/NED ratio with those of the lowest MAP and highest NED.

RESULTS

Among 937 patients, hospital mortality was 29%. After adjustment for clinically relevant covariates, the lowest MAP/NED ratio remained independently associated with hospital mortality (adjusted odds ratio for the highest vs. lowest tertile, 0.60; 95% CI, 0.38-0.92). The AUC of the lowest MAP/NED ratio was 0.625, which was superior to that of the lowest MAP (0.562) and comparable to that of the highest NED (0.625).

CONCLUSIONS

In adult patients receiving vasopressor infusion, the lowest MAP/NED ratio within 24 h of ICU admission was independently associated with hospital mortality. Its prognostic discrimination was slightly higher than that of the lowest MAP value and comparable to that of the highest NED.