The effects of five vasopressors on renal blood flow in septic dogs

Objective

Vasopressors are recommended for circulatory support during acute sepsis. They maintain blood pressure, but have differing effects on cardiac output (CO) and renal blood flow (RBF). In particular, they may impair RBF and increase the risk of renal insufficiency. The aim of the study was to compare the effects on RBF of five vasopressors, noradrenaline (NA), adrenaline (ADR), dopamine (DOP), phenylephrine (PE) and vasopressin (VP), in acute sepsis.

Methods

In seven anaesthetized dogs CO and RBF were measured directly using flow probes. The mean artery pressure (MAP) was measured by cannulating the femoral artery. Systemic vascular resistance (SVR) was derived. Sepsis was induced by injecting Escherichia coli. Each vasopressor was randomly infused at a recommended rate (Table 1) for 30 min. Percentage changes in MAP, CO, SVR and RBF, compared with baseline, were calculated. Data were expressed as mean (SD) and statistical analysis was performed using one-group t tests.

Table 1

Results

All five vasopressors increased MAP (P < 0.01), but their effects on CO varied, with ADR and DOP producing the greatest increases (P < 0.01). SVR was increased by NA, PE and VP (P < 0.01), and was decreased by ADR (P < 0.01). Whereas NA and DOP increased RBF (P < 0.05), RFB was decreased by ADR and PE (P < 0.05; Table 1).

Conclusion

Despite similar effects on MAP, vasopressors have different effects on CO, SVR and RBF. NA and DOP were the most effective vasopressors in preserving RBF during sepsis, while ADR and PE had negative effects.