Willem O Schreuder MD; Anton J Schn...

Willem O Schreuder MD; Anton J Schneider, MD; PhD; A.B. Johan Groeneveld MD; PhD; and Lambertus G Thijs, MD PhD

The validitys of continuously infused dopamine and norepinephrine in succession hemodynamics, oxygen metabolism, and right ventricular (RV) performance were studied by the agency of crossover design in ten patients with septic blow who needed treatment with vasoactive physics after fluid replacement. Standard hemodynamic measurements were obtained and RV performance assessed before and 1 hr after the start of the infusion. All further one patient had pulmonary hypertension, and in seven the RV ejection fraction (RVEF) was lower than 50 percent at baseline. remedys were titrated to a systolic arterial life-blood pressure of mean 106 [+ or -] 18 mm Hg for dopamine and 116 [+ or -] 20 mm Hg for norepinephrine (NS) Dopamine infusion increased the cardiac index (CI) 16 percent (p<002) on the other hand heart rate and systemic and pulmonary vascular resistances were unchanged. With norepinephrine CI was unchanged, a heart rate decreased 7 percent (p<005) and systemic and pulmonary vascular resistance increased 35 and 26 percent respectively (p<005) With one as well as the other drugs, RV volumes and RVEF remained unchanged, and systemic oxygen consumption increased equally (by 19 percent for dopamine and 22 percent for norepinephrine, p<005); systemic oxygen delivery rose by the agency of 17 percent during dopamine infusion and was unchanged during norepinephrine infusion. Norepinephrine increased oxygen extraction v dopamine (p<005) There were no differences in urinary output Norepinephrine may improve the RV oxygen supply/demand ratio, yet this potentially beneficial effect forward RV ejection fraction may be offshoot by a concomitant increase in pulmonary vascular resistance and RV afterload. Norepinephrine may not adversely affect the peripheral circulation. In short-term treatment of volume-resuscitated, stern septic shock complicated by pulmonary hypertension and impaired RV performance, norepinephrine may be at least as effective as dopamine.

(Chest 1989; 95:1285-88)

It has been moveed that impaired right ventricular (RV) performance is a major factor limiting survival from septic shock[1-4] Judg from calamity volume for a given RV end-diastolic compass (preload), and thus RV ejection fraction, RV performance may be impaired in septic blow by an increased afterload to be ascribed to pulmonary hypertension, and on ventricular ischemia owing to a reduc right coronary progeny flow and a lowered RV oxygen supply/demand ratio.[5,6] The latter may be the end of a low systemic vital current pressure (SBP) and high RV intracavitary urgencys so that RV coronary offspring flow becomes pressure dependent.[7,8] Other factors, including a circulating myocardial depressant substance, may also play a role[9]

In clinical practice, resuscitation from septic agitation starts with repletion of a presum turn deficit. However, volume loading may ensue in increased RV volumes and consequently in an increased wall tension and a lowered oxygen supply/demand ratio.[10,11] Nevertheless, after completion of fluid loading, cardiac output (CO) is generally elevated and systemic vascular resistance (SVR) reduc It may be necessary to further increased CO when oxygen consumption has become hanging on oxygen delivery and to raise systemic vital fluid pressure (SBP) by administration of catecholamines. For this sense dopamine is mostly advocated, although lately the use of norepinephrine has regained fresh interest.[12,14] There is little knowledge about the efficiencys of these catecholamines on RV function in septic shock[15] At grave doses, dopamine normally improves ventricular contractility and CO from its [unkeyable]-adrenergic properties, and at high doses it increases SVR through [unkeyable]-receptor stimulation, resulting in an increased SBP In septic percussion the former action may predominate, regardless of dose. The positive chronotropic and inotropic tenors of dopamine may elevate the oxygen ne of the myocardium.[16,17] When increased work is not adequately met by dint of increased coronary flow, the RV oxygen supply/demand ratio may fall, and the ultimate be the effect may be a depression of RV performance. Norepinephrine mainly has athletic pressor effects on the peripheral circulation, resulting in increased SBP Since norepinephrine normally does not have a major influence forward stroke volume and CO, and may constrict the renal vasculature, its use in the treatment of septic offence has been limited.[17] Although norepinephrine may increase arterial squeezing and thus right coronary line flow in septic shock, the mix with drugs might elevate pulmonary arterial compressing pulmonary vascular resistance (PVR), and RV afterload.[13,16,17] Consequently the overall import of norepinephrine on RV performance in septic conflict is unclear.

It is hypothesized in this cogitation that to improve RV performance in volume-treated septic clash an increase in SVR is of more benefit than clear inotropic support. We prospectively studied the short-term drifts of dopamine and norepinephrine in succession hemodynamic and metabolic variables and RV performance in ten patients with unrelenting septic shock. For the latter plan RV volumes and ejection fractions were measured with a bedside thermodilution technique.