Mean Arterial Pressure/Norepinephrine Equivalent Dose Index as an Early Measure for Mortality Risk in Patients With Shock on Vasopressors

Purpose: We aimed to investigate the association between the early mean arterial pressure (MAP)/norepinephrine equivalent dose (NEQ) index and mortality risk in patients with shock on vasopressors and further identify the breakpoint value of the MAP/NEQ index for high mortality risk. Methods: Based on the Medical Information Mart for Intensive Care IV database, we conducted a retrospective cohort study involving 19,539 eligible intensive care unit records assigned to three groups (first tertile, second tertile, and third tertile) by different MAP/NEQ indexes within 24 h of intensive care unit admission. The study outcomes were 7-, 14-, 21-, and 28-day mortality. A Cox model was used to examine the risk of mortality following different MAP/NEQ indexes. The receiving operating characteristic curve was used to evaluate the predictive ability of the MAP/NEQ index. The restricted cubic spline was applied to fit the flexible correlation between the MAP/NEQ index and risk of mortality, and segmented regression was further used to identify the breakpoint value of the MAP/NEQ index for high mortality risk. Results: Multivariate Cox analysis showed that a high MAP/NEQ index was independently associated with decreased mortality risks. The areas under the receiving operating characteristic curve of the MAP/NEQ index for different mortality outcomes were nearly 0.7. The MAP/NEQ index showed an L-shaped association with mortality outcomes or mortality risks. Exploration of the breakpoint value of the MAP/NEQ index suggested that a MAP/NEQ index less than 183 might be associated with a significantly increased mortality risk. Conclusions: An early low MAP/NEQ index was indicative of poor prognosis in patients with shock on vasopressors.