Norepinephrine combined with phenylephrine versus norepinephrine in patients with septic shock: a retrospective cohort study

BACKGROUND Phenylephrine (PE) and norepinephrine (NE) may be used to maintain adequate blood pressure and tissue perfusion in patients with septic shock, but the effect of NE combined with PE (NE-PE) on mortality remains unclear. We hypothesized that NE-PE would not inferior to NE alone for all-cause hospital mortality in patients with septic shock. METHODS This single-center, retrospective cohort study included adult patients with septic shock. According to the infusion type, patients were divided into the NE-PE or NE group. Multivariate logistic regression, propensity score matching and doubly robust estimation were used to analyze the differences between groups. The primary outcome was the all-cause hospital mortality rate after NE-PE or NE infusion. RESULTS Among 1, 747 included patients, 1, 055 received NE and 692 received NE-PE. For the primary outcome, the hospital mortality rate was higher in patients who received NE-PE than in those who received NE (49.7% vs. 34.5%, p<0.001), and NE-PE was independently associated with higher hospital mortality (odds ratio=1.75, 95% confidence interval=1.35–2.27, p<0.001). Regarding secondary outcomes, patients in the NE-PE group had longer lengths of stay in ICU and hospitals. Patients in the NE-PE group also received mechanical ventilation for longer durations. CONCLUSIONS NE combined with PE was inferior to NE alone in patients with septic shock, and it was associated with a higher hospital mortality rate.