genitourinary, integument, and neurologic exam. Particular

attention should be paid to mental status. Delirium is characterized by inattention, altered level of c onsciousness, and

change in cognition. These symptoms tend to fluctuate

over periods of time.

DIAGNOSTIC STUDIES

The purpose of diagnostic studies is to (1) determine the

presence and etiology of sepsis and (2) assess the severity

and response to therapy. A patient with focal symptomatology (fever, cough, purulent sputum) may need only

focused evaluation (chest x-ray) . The discussion that follows assumes the presentation is more nebulous.

..... Laboratory

A typical diagnostic work-up for the presence and etiology

of sepsis involves assessment for leukocytosis or leukopenia (complete blood count), two blood cultures, and urinalysis. Blood cultures should be performed before

administration of antimicrobials, with at least one from a

peripheral site. Each vascular access device should have one

blood culture drawn. Other laboratory assessments, such

as wound cultures, synovial fluid, peritoneal fluid, and

CHAPTER 34

cerebrospinal fluid, should be obtained when clinical suspicion indicates.

Because severe sepsis is defined by organ failure, look

for evidence of acute kidney injury, shock liver (elevated

bilirubin), coagulopathy (elevated prothrombin time/

international normalized ratio/partial thromboplastin

time), and thrombocytopenia. Pa02 measurement

compared with Fi02 may be useful in determining the

presence of acute lung injury and acute respiratory distress

syndrome.

Patients with sepsis should undergo risk stratification.

This begins with initial lactate assessment with levels

>4 mmol!L diagnostic for severe sepsis. Although arterial

and venous samples are nearly equivalent, lactate is ideally

measured at the bedside. In the time it takes for blood to

travel to the lab, blood cells undergo anaerobic metabolism, causing false elevations. Repeat measurement should

occur after treatment or after 6 hours. Clearance of lactate

(delta lactate) of 1 0% or greater indicates a significant

reduction in mortality, whereas no change may signify a

60% mortality.

..... Imaging

Chest radiographs are typically included for most septic

patients when the presentation is concerning or the etiology is uncertain. Targeted imaging should be considered

based on clinical presentation ( eg, computed tomography

scan of the abdomen/pelvis in the febrile patient with

abdominal pain and recent surgery for Crohn disease to

assess for potential abscess).

PROCEDURES

Targeted diagnostic procedures should be considered when

indicated, such as lumbar puncture for suspected meningitis or arthrocentesis for suspected septic joint.

Invasive central monitoring such as central line

placement, arterial line, and urinary catheterization is

indicated when there is evidence of acute end-organ fail ­

ure, lactate �4 mmol/L, or shock.

MEDICAL DECISION MAKING

The initial step is to determine who is at risk for infection.

Next, determine the sepsis severity through clinical assessment, point of care lactate, laboratory assessment for endorgan injury, and blood pressure response to fluid

resuscitation. Patients with uncomplicated sepsis should

have investigation to determine the infectious source and

be treated with antimicrobials and fluids.

Patients with severe sepsis and septic shock should

receive early aggressive resuscitation, including early antimicrobial therapy and early goal-directed therapy (EGDT).

Resuscitation should occur concurrent to the diagnostic

evaluation, not after it (Figure 34-1).

TREATMENT

Antibiotics should be administered as early as possible,

preferably within 1 hour of recognition of septic shock.