If Scvo2 or SVo2 of 70% or 65%, respectively, is not achieved with fluid resuscitation to the central venous pressure target, then transfusion of packed red blood cells to achieve a hematocrit of ≥ 30% and/or administration of a dobutamine infusion (up to a maximum of 20 µg • kg-1 • min-1) be used to achieve this goal.
It is important to remember that vasopressors should be utilized not only when fluids fail to reverse hypotension, but also during resuscitation to maintain minimally adequate blood pressure. Traditionally, the use of noradrenalin in patients with shock has been restricted by the fear of excessive vasoconstriction that may result in end-organ hypo perfusion. In the past it was usually given only when other vasopressin agents failed, and thus such patients would be predicted to have a poor outcome. Recent studies indicate that the fear of deleterious effect was unwarranted and that noradrenalin may have a role as a first-line vasopressor agent in patients with septic shock.
Vasopressin should be considered in refractory shock despite high dose conventional vasopressors. Vasopressin is an endogenously produced hormone that is deficient in many patients with septic shock. Exogenously administered vasopressin in physiologic replacement doses may act synergistically with other vasopressor agents, and has been associated with early withdrawal of catecholamine. Most studies have evaluated short-term infusions of vasopressin at 0.08 U/minute or less as add-on therapy in patients requiring adrenergic agents. The results show that starting vasopressin in patients with septic shock increases systemic vascular resistance and arterial blood pressure, thus reducing the dosage requirements of adrenergic agents [12]. These effects are rapid and sustained. Substantial enhancement of urine production, likely due to increased glomerular filtration rate, was shown in several studies. A few studies demonstrated clinically significant reduced cardiac output or cardiac index after vasopressin was begun, necessitating cautious use in patients with cardiac dysfunction.