Sepsis

Definitions 3.4.1.1

Systemic Inflammatory Response Syndrome

If a patient presents with at least two of the criteria listed in Table 3.5, but lacks evidence for infection, the conditions for a systemic inflammatory response syndrome (SIRS) are met. The SIRS is the uniform answer of the body to a variety of diseases such as pancreatitis, major operation, severe trauma, or ischemia. Additionally a drop in the platelet count and the antithrombin-III levels (AT-III) is usually seen (Fresenius and Heck 2001).

Table 3.5. Definition of the systemic inflammatory response syndrome

Temperature >38°C or <36°C Tachycardia > 90 beats/min

Respiratory insufficiency (at least one of the following three criteria)

Respiratory frequency > 20/min

Hyperventilation paCO2 <32 mmHg (with spontaneous respiration)

paO2 < 70 mmHg (during spontaneous respiration) or paO2/FjO2 <175 (during mechanical ventilation with absence of pulmonary disease) WBC > 12,000/|l or <4,000/|l or > 10% immature bands

For the diagnosis of SIRS at least two criteria have to be met From AACP/SCCM (1992); WBC white blood cell count

3.4.1.2 Sepsis

If the source of an infection can be located and the SIRS criteria are present, the definition of sepsis is met. The incidence of sepsis is five per 1,000 inpatients; the 28-day mortality varies between 25% and 35%, in severe sepsis up to 60 %.

The definition for severe sepsis includes the standard sepsis criteria in conjunction with signs of organ dysfunction, hypoperfusion, or sepsis-induced hypotension, which present as lactate acidosis, oliguria, en-cephalopathy, or thrombocytopenia.

A septic shock is the combination of sepsis with arterial hypotension, defined as arterial blood pressure below 90 mm Hg(ora decrease of more than 40 mm Hg from the baseline value for more than 1 h) despite adequate fluid resuscitation. It is accompanied by decreased perfusion or dysfunction of the organs.

Standard Therapy for Sepsis

The standard therapy for sepsis consists of the following:

• Identification and verification of the origin of the sepsis and removal of this focus (surgery and/or anti-infectious therapy)

• Accompanying antimicrobiologic treatment, initially as broad calculated antibiotic therapy using a combination of two or more antibiotics according to the CID (Centre of Infectious Disease) guidelines, after antibiogram testing-specific deescala-ting antibiotic treatment

• Optimization of organ perfusion and oxygen delivery with catecholamines

• Early mechanical ventilation

• Transfusion of red blood cells until the hematocrit reaches 30 %

• Volume resuscitation with crystalloid or colloid solutions

• Decreasing peripheral oxygen consumption by lowering of body temperature, analgesia, and sedation

• Early enteral nutrition

Early Goal-Directed Therapy for Sepsis

In 2001 Rivers et al. (2001) presented a new treatment strategy for sepsis that reduced the in-hospital mortality from 46.5% to 30.5% when compared to standard treatment with the so called early goal-directed therapy (EGDT). Patients were included in this study if they met the SIRS criteria and showed signs of global tissue hyp-oxia, which was defined by a systolic pressure of 90 mmHg or below or a lactate level of 4 mmol/l or higher.

After assessment and consent, the patients were randomized either to the standard therapy group or the EGDT group. In both groups, treatment was commenced in the emergency room; after at least 6 h the patients were transferred to an intensive care unit, where the consecutive treatment did not differ between groups and where the intensivists were blinded to the initial treatment group assignments. In both groups, the central venous pressure (CVP) was kept at or above 8-12 mmHg with boluses of 500 ml crystalloid solutions every 30 min, the mean arterial pressure (MAP) monitored with an arterial cannula was kept at or above 65 mmHg with vasoactive agents and the urine output was kept at or above 0.5 ml/kg/h.

The particular feature of the EGDT was to install continuous central venous oxygen saturation monitoring (ScvO2), which was achieved by inserting a specialized central venous catheter and monitoring system (Edwards Lifesciences, Irvine, CA, USA). ScvO2 has been shown to be a surrogate for the cardiac index as a target for hemodynamic therapy. If ScvO2 was below 70%, transfusion of red cells was begun until the hematocrit reached 30 %. If ScvO2 was still below 70 % infusion of dobutamine began. Dobutamine was started at a dose of 2.5 |g/kg/min that was increased by 2.5 |g/ kg/min every 30 min until ScvO2 reached 70% or a maximum dose of 20 |g/kg/min was given. Dobutami-ne was decreased in dose or discontinued if the mean arterial pressure was less than 65 mmHg or if the heart rate was above 120 beats per minute. To decrease oxygen consumption, patients in whom hemodynamic optimization could not be achieved received mechanical ventilation and sedatives (see Fig. 3.5).

Heidelberg Sepsis Pathway

See Fig. 3.6 for the Heidelberg sepsis pathway.

Fig. 3.5. Protocol for early goal directed therapy for sepsis. CVP central venous pressure, MAP mean arterial pressure, ScvO2 central venous oxygen saturation. From Edwards Lifesciences (2006)

Fig. 3.6. Heidelberg sepsis pathway. CVP central venous pressure, MAP mean arterial pressure, ScvO2 central venous oxygen saturation. Modified from Nieminen et al. (2005)

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