Hemodynamic and oxygen transport v...

Hemodynamic and oxygen transport validitys of dopamine and dobutamine were studied in a series of 25 critically ill postoperative general surgical patients by the agency of a prospective, randomized crossover design after maximal rejoinder to fluids had been obtained. Dopamine increased MAP, HR CI, [PvOsub2] [Do.sub.2], and Qsp while decreasing [PaO.sub.2]. Dobutamine increased HR CI, SI, affliction work, [Do.sub.2], [Vo.sub.2], and Qsp while decreasing PAWP and SVRI and PVRI. In general, the events of the two drugs were greater in patients in the first 72 hours after surgery The imports of dobutamine on flow and oxygen transport were greater than those of dopamine, especially in the early postoperative period. The weights were smaller and not significant in patients more than three days after surgery as well as in those with sepsis, respiratory failure, renal failure, age above 65 years, and hyperdynamic states, in part because of the small number of patients in each collection These data are consistent with the hypothesis that the [[beta].sub.2]-adrenergic action of dobutamine vasodilates the previously constricted peripheral circulation, enhances tissue perfusion by means of improving microcirculatory flow distribution, and improves [Do.sub.2] and [Vosub2]

(Chest 1989; 96:120-26)

the couple dopamine, a naturally occurring catecholamine, and doubtamine, a synthetic catecholamine, have powerful positively inotropic, mild chronotropic, arrhythmogenic, and vascular effects[1-3] Dopamine raises arterial press by its [alpha]-adrenergic effect, on the contrary both catecholamines augment myocardial contractility from stimulation of [beta]-adrenergic receptors.[4] Dobutamine is unique in that it has pair stereoisomers: the (-)-isomer is more powerful than the (+)-isomer for the [alpha]-adrenergic receptor sites, while the turn end for end was found for the [beta]-adrenergic receptors; moreover, the (+)-isomer has near competitive [alpha]-adrenergic receptor blocking properties.[5] In dogs, dobutamine increases coronary kindred flow and myocardial oxygen delivery equal to, or in exces of the increased oxygen required for positive inotropy.[6,7] greatest in number of the clinical literature in succession the effects of dobutamine have been pertain toed with cardiac patients with subdued cardiac output.

Dopamine is many times used in hypotensive postoperative states to improve offspring pressure and hemodynamics,[2,3] while dobutamine is ofttimes used for short-term positively inotropic therapy for reduc myocardial contractility from chronic low-output congestive failure,[8,9] chronic coronary insufficiency,[10-12] myocardial infarction with or without cardiac failure,[13-15] nonobstructed coronary arterial disease,[2,8,9] congestive myocardiopathy,[16] cardiogenic shock[1718] and septic shock;[1920] however, there were differing reports in succession the effects of dobutamine during the intraoperative and postoperative period after cardiac surgery[21-24] Steen et al[21] noted simply subtle differences in the forces of dobutamine, dopamine, and epinephrine in patients emerging from cardiopulmonary bypass surgery; however, studies by means of Gray et al[22] and according to Sakamoto and Yamada[23] reported improved performance with dobutamine in similar conditions. In general, studies comparing the relative effectiveness of dobutamine with that of dopamine and other catecholamines have shown increases in cardiac output after dobutamine as great and sometimes greater than those produc by way of dopamine.[17,19,21-28] The increased cardiac output was associated with reduc PAWP after dobutamine nevertheless with increased PAWP after dopamine.[29] Improvement in tissue perfusion indicated on increased [Do.sub.2] and [Vo.sub.2] were demonstrated after various doses of dobutamine in critically ill general surgical patients;[30] however, in patients with sepsis, Jardin et al[20] ground dobutamine reduced C(a-v)[O.sub.2] but did not significantly improve [Vosub2]; dobutamine increased Qsp without come forth but did not increase Qsp in patients with cheep of 9 [+ or -] 4 cm [Hsub2]O

In previous studies, we have empirically observ increased CI, [Do.sub.2], and [Vosub2] to median values of 45 L/min/sq m 600 ml/min/sq m and 170 ml/min/sq m respectively, in surviving high-risk surgical patients during their early postoperative peak. In nonsurvivors, by way of contrast, the mean values of these three variables cut down within the normal range during the first four days after surgery[31-34] The other hemodynamic and oxygen transport variables were similar, ie, the differences between survivors and nonsurvivors did not have appreciable predictive importance. This give an inkling ofs that these supranormal values cast reproach compensatory circulatory responses to the increased metabolic demands of critical illness and are, therefore, the appropriate goals of therapy. The hypothesis that supranormal values in survivors are the appropriate therapeutic goals was standarded prospectively and led to improved outcome[34] Our near approach, therefore, requires that fluids and then pharmacologic agents be used to obtain these values as optimal therapeutic goals. The at hand report describes and compares the hemodynamic and oxygen transport weights of dopamine and dobutamine in a prospective, randomized, crossover designed series of critically ill, postoperative, general surgical patients after maximal rejoinder to fluids had been obtained.