[Effect of dopamine and norepinephrine on hemodynamics and tissue oxygenation of patients with septic shock].

OBJECTIVE: To evaluate the effects of dopamine (DA) and norepinephrine (NE) on hemodynamics and tissue oxygenation of patients with septic shock.

METHODS: Sixteen patients with septic shock were assigned to the groups of DA and NE randomly. They were given DA or NE for 4 hours, then shifted to NE or DA. Heart rate (HR), mean artery pressure (MAP), cardiac index (CI), stroke index (SI), systemic vascular resistance index (SVRI), acceleration index (ACI), left cardiac work index (LCWI), thoracic fluid content (TFC), mixed venous oxygen saturation (SvO2), venous lactate concentration (Lac), and urine volume per hour (UV) were measured at the end of the 1st, 2nd, 3rd, and 4th hour of the treatment for each of the two drugs. Creatinine clearance rate (CCr) was measured at the end of the 4th hour of study. The differences of all parameters were compared between the two groups.

RESULTS: (1)There were no differences in MAP, SI and TFC between the two groups (P>0.05), and there was significant difference in LCWI between the two groups at the end of the 2nd hour (P=0.031). HR, CI and ACI were higher while SVRI was lower in DA group than that in NE group, with significant differences between the two groups (P<0.05 or P<0.01). The results suggested that both DA and NE had good effect on raising blood pressure; DA was more effective than NE in increasing oxygen delivery (DO2), but its use was confined to certain extent due to its effect of accelerating HR. (2) There were no significant differences of SvO2 between the two groups (P>0.05),and the levels of Lac in the group of DA were significantly higher than those in the group of NE (all P<0.05). The results suggested that NE was better than DA in improving internal organ perfusion and tissue oxygenation. (3)UV in the group of DA was significantly higher than that in the group of NE at different time points (P<0.05 or P<0.01). CCr at the end of the 4th hour in DA group was significant higher than that in NE group (P=0.023). The results suggested that DA had significant effects in increasing urine and CCr, denoting that it might have an effect in protecting renal function.

CONCLUSION: DA has better effect of increasing DO2 than NE, but its side effect of accelerating HR may to some degree restrict its use. NE may has better effects than DA on enhancing visceral perfusion and tissue oxygenation. DA may be a better choice for patients with septic shock accompanied by oliguria and/or renal dysfunction. NE may be a better choice for the patients of septic shock with tachycardia and/or severe tissue hypoxia.