The effects of low-dose dopamine infusions on haemodynamic and renal parameters in patients with septic shock requiring treatment with noradrenaline.

OBJECTIVE

To investigate whether low-dose dopamine (LDD) has a significant effect on systemic haemodynamic variables and renal function when used in conjunction with high-dose noradrenaline in optimally volume-resuscitated patients with septic shock.

DESIGN

A prospective clinical study in which each patient acted as his/her own control.

SETTING

Teaching hospital Intensive Care Unit.

PATIENTS

Twenty-one patients with septic shock treated with high-dose noradrenaline were studied, 17 patients completed the study.

INTERVENTIONS

Fluid loading to an optimal left ventricular stroke work index (LVSWI) whilst on more noradrenaline than 10 mcg/min and dopamine of 2.5 mcg/kg per min. Three study periods each of 2 h with LDD present, withdrawn and restarted. During each period a complete haemodynamic profile and measurement of urine flow rate, creatinine clearance and sodium excretion was performed.

MEASUREMENT AND RESULTS

Removing and restarting LDD caused marked changes in cardiac index (CI, 17% fall, p < 0.01: 23% rise, p < 0.01), stroke volume (SV, 11% fall, p < 0.05: 14% rise, p < 0.05) and systolic blood pressure (SBP, 11% fall, p < 0.05: 14% rise, p < 0.05). Urine volume fell by 40% (p < 0.05) when dopamine was withdrawn. Significant reductions in sodium excretion (p < 0.05) and fractional sodium excretion (p < 0.05) also occurred on stopping LLD. Changes in creatinine clearance were not statistically significant.

CONCLUSION

Low-dose dopamine causes significant increases in SBP SV, cardiac output and urine flow during treatment with noradrenaline.