As mentioned above, there are several instances in which the provider should be very cautious about using aggressive fluid resuscitation, as it may worsen the shock state If signs of hepatomegaly or pulmonary edema develop, ongoing fluid resuscitation should be reevaluated It is also important to perform ongoing clinical assessment of the patient response to fluid administration One option is to monitor the hemodynamic changes as fluid is rapidly administered, as a decrease in heart rate and increase in blood pressure suggest that the patient is appropriately responding to fluid administration Bedside dynamic maneuvers can approximate this therapeutic effect to predict if a patient is likely to respond positively to a fluid bolus For example, a transient decrease in heart and/or increase in blood pressure in response to a passive leg raise or gentle palpation over the liver that augments cardiac preload have been shown to predict which patients are likely to benefit from additional fluid administration For patients with an arterial catheter in place, pulse pressure variation ≥15% has also been associated with fluid responsiveness POCUS can also be helpful for serial assessments of volume status If there is underlying congenital heart disease, severe malnutrition, or critical level of anemia, fluid administration could precipitate or worsen congestive heart failure Similarly, if myocarditis is suspected, fluid administration should proceed cautiously, with initial volumes of to 10 mL/kg rather than 20 mL/kg Finally, in patients with pre-existing oliguric or anuric renal failure, judicious fluid administration is important as the child may not be able to mobilize the administered fluid after shock reversal Vasoactive Agents Two randomized trials in pediatric septic shock have provided evidence that epinephrine as first-line vasoactive therapy is more effective at reducing mortality than dopamine As such, epinephrine, rather than dopamine, is considered a firstline vasoactive therapy for fluid-refractory shock However, in children with a low SVR state in septic, distributive, or neurogenic shock, norepinephrine may be preferentially used as the first-line vasoactive therapy Table 10.4 describes the mechanism of action and considerations for use of vasoactive agents They may be run initially via peripheral IV or an IO in dilute concentrations, but should be transitioned to a central vein once central venous access is obtained The decision to add a second vasoactive agent in the ED setting should be considered for patients in whom hypotension persists despite titration of the initial vasoactive therapy For patients with “warm” shock, if initially receiving norepinephrine, addition of vasopressin or epinephrine may be considered Case reports, case series, and one trial indicate that administration of vasopressin is associated with an increase in mean arterial blood pressure and urine output in