Evaluation of procalcitonin at James Paget Intensive Care Unit

Introduction

Procalcitonin (PCT) offers the possibility of differentiating bacterial infection from viral or non-infectious reactions. PCT can be used to support decision-making on initiation or discontinuation or change of antibiotic therapy. Our aim was to determine the usefulness of PCT in our ICU.

Methods

PCT was measured once daily for all patients admitted to the ICU. Results were reviewed daily by intensivists and microbiologists and an appropriate decision about antibiotic therapy was made. We considered to stop antibiotics if the PCT was <0.5 ng/ml or had decreased to 80% of the peak value. CRP and clinical progression were also taken into consideration.

Results

One hundred and fourteen PCT values were obtained from 27 patients over 18 ICU days. PCT concentrations were lower than 0.5 ng/ml in 49 samples whilst CRP values were higher with a median of 107.5 mg/l. Antibiotics were discontinued or not initiated following low PCT values in 38 of these samples despite high CRP. For two patients who were already on antibiotics, a rise in PCT was noticed which prompted us to change the antibiotics. No new microbiologically proven systemic infection was identified in any of the patients with low PCT values. See Figure 1.

Figure 1

Example 1 (left): sepsis secondary to hydronephrosis. This graph clearly shows the rise in procalcitonin (PCT) during early onset of sepsis and its fall during antibiotic treatment. Antibiotics were discontinued when the PCT level fell to 80% of its peak value on day 8. Example 2 (right): laparoscopic cholecystectomy complicated by bile peritonitis. Good response to antibiotics initially, but PCT started to rise on day 12 which prompted us to change antibiotics. Serial PCT is useful to assess the response to treatment.

Conclusions

Frequently, discrepancy between PCT and other inflammatory markers were noticed, suggesting an inflammatory response or nonbacterial infection and not necessarily an indication for antibiotics. Regular assessment of PCT, when interpreted with clinical context, was helpful not only to decrease the duration of antibiotics but also to change the antibiotic regimen.