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"Among a large array of laboratory variables, procalcitonin has emerged as the leading one to indicate systemic infections with high accuracy," senior author Dr. Stefan Schroeder, from West Coast Hospital, Heide, Germany, told Reuters Health.

"There is extensive clinical evidence that procalcitonin allows reliable differentiation between systemic inflammatory response syndrome and bacterial or fungal sepsis and closely correlates with the systemic severity of infections in various diseases and medical disciplines," he added. "Moreover, some recent clinical studies have also shown that procalcitonin is a reliable means to guide antibiotic therapy in community acquired pneumonia and sepsis."

The goal of the present study was to determine if a procalcitonin-based algorithm could be used to guide antibiotic therapy in intensive care patients. Included in the investigation were 110 surgical intensive care patients who were receiving antibiotic therapy for confirmed or suspected high-grade bacterial infections. All of the subjects met at least two standard criteria for a systemic inflammatory response syndrome.

The subjects were randomized to receive antibiotic therapy for 8 consecutive days or as dictated by procalcitonin levels. In the procalcitonin group, if a patient had clinical improvements in signs and symptoms and if the procalcitonin level fell below 1 ng/mL or dropped by 25% to 35% from the initial value over 3 days, then antibiotic therapy could be discontinued.

The duration of antibiotic therapy was reduced by 2 days, on average, in the procalcitonin group compared to controls: 5.9 vs. 7.9 days (p <>

"Beyond a reduction of the length of antibiotic treatment, procalcitonin-guidance also had a favorable effect on the length of the intensive care stay," Dr. Schroeder said. The average length of stay was 15.5 days in the procalcitonin group compared with 17.7 days in the control group (p = 0.046).

The results clearly show that a procalcitonin-guided algorithm is a helpful approach to reduce the length of antibiotic therapy without negatively influencing the outcome of surgical intensive care patients, Dr. Schroeder said.

"Monitoring of procalcitonin is a valuable tool for therapeutic decision-making concerning the length of antibiotic treatment," he added. "However, adequate interpretation of procalcitonin concentrations always requires the background of clinical course and symptoms. This concept contributes to less extensive antibiotic treatment with positive effects on economical factors and the development of drug-resistances in intensive care medicine."

Regarding future research, Dr. Schroeder said that "our procalcitonin-based algorithm is certainly practicable and simple. However, procalcitonin cut-off points for antibiotic termination have not uniquely defined. Thus, procalcitonin-controlled antibiotic therapy must still be tested in heterogenous groups of patients, particularly the safety."

Crit Care. 2009;13:R83.

Clinical Context

Study Highlights

• Participants for study enrollment were all admitted to 1 surgical intensive care unit in Germany. All participants required antibiotic therapy based on confirmed or highly suspected bacterial infection along with at least 2 criteria for systemic inflammatory response syndrome.
• Participants were randomly assigned in the open-treatment study to receive either 8 days of antibiotics or a varying course of antibiotics based on procalcitonin levels. Antibiotics were discontinued among subjects in the procalcitonin-guided therapy group when the procalcitonin level decreased to less than 1, or when this value decreased by 25% to 35% of the initial value during 3 days.
• The type of antibiotic chosen was left to the discretion of the treating physician.
• The main outcomes of the study were the duration of antibiotic use, the duration of stay in the intensive care unit, and participants' clinical outcomes of hospitalization.
• 57 patients were assigned to the procalcitonin-guided therapy group, and 53 comprised the control group. The mean age of participants was 67 years old, and peritonitis and pneumonia accounted for the vast majority of admissions. The severity of illness between groups at baseline was similar.
• The most popular antibiotic choices for all patients were acylaminopenicillin plus a beta-lactamase inhibitor or nitroimidazole.
• Procalcitonin-guided therapy was associated with a significantly shorter duration of antibiotic treatment vs standard therapy (5.9 days vs 7.9 days, respectively).
• Procalcitonin-guided therapy was also associated with a shorter stay in the intensive care unit vs standard therapy (15.5 days vs 17.7 days, respectively).
• Disease severity scores remained similar between groups during the study, as did leukocyte counts and C-reactive protein concentrations.
• 14 participants in the control group died during hospitalization vs 15 subjects in the procalcitonin-guided therapy group. This difference between groups was not significant.

Clinical Implications

• Sepsis can be difficult to diagnose among critically ill patients, as common signs of sepsis are nonspecific in the setting of severe illness, and traditional laboratory tests may lag behind progression of infection.
• In the current study, antibiotic treatment guided by procalcitonin levels reduced the durations of antibiotic therapy and intensive care unit stay among critically ill surgical patients. Procalcitonin-guided therapy did not harm clinical outcomes vs standard therapy.