Shock Syndromes I

presenting after motor vehicle collision likely has hypovolemic shock, whereas a patient presenting after bee

sting likely has vasodilatory/distributive shock (immune-mediated [anaphylactic] subtype).

different (but sometimes overlapping) treatment goals and therapeutic strategies. Although the rest of this

chapter focuses on the first 2 phases, understanding the phase of a patient’s circulatory shock is essential for

establishing treatment goals and subsequent therapeutic approaches.

Salvage: The first phase focuses on salvage, in which efforts should be directed to achieving the minimum

perfusion pressure and CO needed to maintain the patient’s survival. Treating the underlying cause of

the patient’s shock, which consists of lifesaving measures, should be done at this time. Examples of

these measures include antimicrobials for sepsis, revascularization for acute myocardial infarction, and

surgical hemostasis for trauma.

Stabalization: In the third phase, patient stabilization is targeted with the goal of preventing or

minimizing end-organ dysfunction.

De-escalation: The fourth phase is de-escalation, in which the goals of therapy include vasoactive

medications weaning (or cessation), fluid elimination (e.g., diuresis or ultrafiltration), and antimicrobial

de-escalation as dictated by microbiology cultures, local antibiogram, and patient clinical picture.

As noted earlier, blood pressure is the driving pressure for peripheral blood flow. As such, an adequate

blood pressure is vital to ensure end-organ perfusion.

SBP or diastolic blood pressure as a therapeutic target.

The perfusion pressure of any organ can be calculated by subtracting the pressure within the organ or

anatomic space from the MAP (e.g., cerebral perfusion pressure = MAP − intracranial pressure).

The target blood pressure for a patient in shock is usually a MAP greater than 65 mm Hg or an SBP

greater than 90 mm Hg, but this must be individualized according to other clinical/biochemical markers

of perfusion.

MAP is an insensitive resuscitation parameter (e.g., blood pressure may be at goal when CO is inadequate),

because of this, additional resuscitation parameters should be used to ensure the optimization of all

hemodynamic components that may influence end-organ perfusion and Do2.

These additional resuscitation goals typically include ensuring (1) adequate end-organ perfusion, (2)

lack of fluid responsiveness, and (3) adequate Do2.

Each organ has a critical perfusion pressure that must be exceeded to maintain adequate perfusion. This

critical perfusion pressure is organ- and patient-specific because of adaptation for chronic conditions.

decreases.

Adequate organ perfusion is best assessed clinically on a per-patient basis.