Mean arterial pressure to norepinephrine equivalent dose ratio for predicting renal replacement therapy requirement: a retrospective analysis from the MIMIC-IV

This study aimed to assess the predictive value of the ratio of mean arterial pressure (MAP) to the corresponding peak rate of norepinephrine equivalent dose (NEQ) within the first day in patients with shock for the subsequent renal replacement therapy (RRT) requirement.

Patients were identified using the Medical Information Mart for Intensive Care IV (MIMIC-IV) database. The relationship was investigated using a restricted cubic spline curve, and propensity score matching(PSM) was used to eliminate differences between groups. Odds ratios (OR) with 95% confidence intervals (CI) were calculated using logistic regression. Variable significance was assessed using extreme gradient boosting (XGBoost), and receiver operating characteristic (ROC) curves were generated.

Of the 5775 patients, 301 (5.2%) received RRT. The MAP/NEQ index showed a declining L-shaped relationship for RRT. After PSM, the adjusted OR per 100 mmHg/mcg/kg/min for RRT was 0.93(95% CI 0.88–0.98). The most influential factors for RRT were fluid balance, baseline creatinine, and the MAP/NEQ index. The threshold for the MAP/NEQ index predicting RRT was 161.7 mmHg/mcg/kg/min (specificity: 65.8%, sensitivity: 74.8%) with an area under the ROC curve of 75.9% (95% CI 73.1–78.8).

The MAP/NEQ index served as an alternative predictor of RRT necessity based on the NEQ for adult patients who received at least one vasopressor over 6 h within the first 24 h of intensive care unit(ICU) admission. Dynamic modulation of the MAP/NEQ index by the synergistic use of various low-dose vasopressors targeting urine output may be beneficial for exploring individualized optimization of MAP.