Mean arterial pressure/norepinephrine equivalent dose index as an early measure of initiation time for enteral nutrition in patients with shock: A prospective observational study

The aim of this study was to compare the predictive ability of the norepinephrine dose (NE), norepinephrine equivalent dose (NEQ), and mean arterial pressure (MAP)/NEQ index to predict the optimal time to initiate enteral nutrition in patients with shock on vasopressors. We prospectively enrolled patients with shock who were receiving vasopressors and followed them for ≤28 d after enrollment. Patients who developed feeding intolerance (FI) during the follow-up period were allocated to the FI group and the remaining patients were allocated to the non-feeding intolerance (non-FI) group. The primary outcome was FI occurrence. The receiving operating characteristic curve (ROC) was used to evaluate the thresholds and predictive ability of NE, NEQ, and the MAP/NEQ index to predict FI. Of the 66 patients enrolled, 47 developed FI. The MAP/NEQ index showed good predictive ability 6 h before EN initiation. The threshold of the MAP/NEQ index for predicting FI was 417 mmHg·μg·kg·min–1 (specificity: 52.9%, sensitivity: 81%) with an area under the ROC curve (AUC) of 70.3% (95% confidence interval [CI], 55.1–85.5; P = 0.015). The threshold for the NE was 0.2 μg·kg/min–1 (specificity: 47.1%, sensitivity: 88.1%), with an AUC of 65.3% (95% CI, 48.2–82.5; P = 0.067), and that for the NEQ was 0.2 μg·kg/min–1 (specificity: 47.1%, sensitivity: 88.1%), with an AUC of 66.2% (95% CI, 49.3–83; P = 0.053). Compared with the NE and NEQ, it could be possible with the MAP/NEQ index to distinguish earlier whether patients with shock receiving vasopressors were suitable for initiation of EN, thereby avoiding FI.