Corresponding Bundle Element:
“In the event of persistent hypotension despite fluid resuscitation (septic shock) and/or lactate > 4 mmol/L (36 mg/dl) achieve central venous pressure (CVP) of > 8 mm Hg.”
Related Measures
Central Venous Pressure Goal
Background:
Goal-directed therapy represents an attempt to predefine resuscitation end-points to help clinicians at the bedside to resuscitate patients in septic shock. The end-points used vary according to the clinical study but attempt to adjust cardiac preload, contractility, and afterload to balance systemic oxygen delivery with demand.
Two essential features of early goal directed therapy include: 1) maintaining an adequate central venous pressure (CVP) to carryout other hemodynamic adjustments; and 2) maximizing mixed or central venous oxygen saturation, discussed elsewhere.
Following the Sepsis Resuscitation Bundle, once lactate is > 4 mmol/L (36 mg/dl), or hypotension has been demonstrated to be refractive to an initial fluid challenge with 20 mL/kg of crystalloid or colloid equivalent, patients should then have their CVP maintained > 8 mm Hg.
Of note, in adhering to this strategy, patients receive the initial minimum 20 mL/Kg fluid challenge prior to placement of a central venous catheter and attempts to maximize CVP. This recommendation is consistent with the methods used in Rivers et al. [1]
Maintaining CVP:
Techniques to maintain an appropriate CVP amount to placing a central venous catheter and delivering repeated fluid challenges until the target value is achieved. Fluid challenges are distinct from an increase in the rate of maintenance fluid administration (see Treat Hypotension and Elevated Lactate First with Fluids).
Consider Blood Products:
In carrying out early goal directed therapy, one key aim is central venous pressure, but it is also imperative to maintain central or mixed venous oxygen saturation targets. If a patient is both hypovolemic and anemic with a hematocrit less than 30 percent of blood volume, it is appropriate to transfuse packed red blood cells. This may have the dual advantage of increasing oxygen delivery to ischemic tissue beds and keeping central venous pressure > 8 mm Hg for longer periods than fluids alone.
Special Considerations:
In mechanically ventilated patients, a higher target central venous pressure of 12–15 mm Hg is recommended to account for the presence of positive end expiratory pressure and increases in intrathoracic pressure.
Similar consideration to the above may be warranted in circumstances of increased abdominal pressure.
Although the cause of tachycardia in septic patients may be multifactorial, a decrease in elevated pulse with fluid resuscitation is often a useful marker of improving intravascular filling.
River’s Protocol:
Rivers et al. performed a randomized, controlled, predominantly blinded study in an 850-bed tertiary referral center over a 3-year period. This study was performed in the emergency department of the hospital and enrolled patients presenting with severe sepsis or septic shock who fulfilled two of the four systemic inflammatory response syndrome criteria in association with a systolic blood pressure of < 90 mm Hg after a 20–30 mL/kg crystalloid challenge or a blood lactate concentration of > 4 mmol/l (36 g/dl).
The patients were randomized to receive six hours of standard therapy or six hours of early goal-directed therapy before admission to the intensive care unit. Clinicians who were subsequently involved in the care of these patients were blinded to the treatment arm of the study.
The control group’s care was directed according to a protocol for hemodynamic support. The aims of this protocol were to ensure that the patients had a central venous pressure of between 8 and 12 mm Hg, a mean arterial pressure of > 65 mm Hg, and a urine output of > 0.5 mL·kg-1·min-1. These goals were targeted with the use of 500-mL boluses of crystalloid or colloid and vasopressor agents as necessary. The patients assigned to the early goal-directed therapy group received a central venous catheter capable of measuring ScvO2. Their treatment aims were then the same as the control groups, except that they also had to achieve a ScvO2 of > 70 percent.
The patients assigned to the early goal-directed therapy group received a central venous catheter capable of measuring ScvO2. Their treatment aims were then the same as the control groups, except that they also had to achieve a ScvO2 of > 70 percent. This was achieved first by the administration of transfused red blood cells, then with positive inotropic therapy, and if this goal was then not achieved, by sedation and mechanical ventilation to reduce oxygen demand.
The study enrolled 263 patients equally between the two groups. There were no significant differences between the two groups at baseline. During the initial 6 hours of therapy, the early goal-directed therapy group received more intravenous fluid (5.0 vs. 3.5 L, p < .001), red cell transfusions (p < .001), and inotropic therapy (p < .001). During the subsequent 66 hours, the control group received more red cell transfusions (p < .001), more vasopressors (p = .03), and had a greater requirement for mechanical ventilation (p < .001) and pulmonary artery catheterization (p = .04). This in part reflects the fact that the control group patients were relatively under-resuscitated initially, and this was noticed and thus acted on by clinicians later on in their treatment course. In-hospital mortality was significantly higher in the control group than in the early goal-directed therapy group (46.5 percent vs. 30.5 percent, p = .009). These differences were maintained through to 28 (p = .01) and 60 days (p = .03).
References:
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