Procalcitonin in the post-operative burns patient

Abstract

Background: Infectious complications are common in hospitalized burns patients, with a high incidence contributing to significant morbidity and a high mortality. Serum Procalcitonin (PCT) has emerged as a biomarker to diagnose sepsis and infection. Following invasive bacterial infection PCT is detectable in peripheral blood. Levels of PCT more than 0.5μg/L are regarded as abnormal.

Objectives: The aim of our study was to determine if there is a correlation between serum PCT post burn wound debridement and burn related sepsis. The primary objective is to determine serum PCT level threshold post burn wound debridement that correlates with a positive blood culture. Our secondary objective was to describe factors associated with elevated PCT post burn wound debridement.

Methods: 34 participants were recruited into the study from 1st November 2019 to 31st July 2020. Serum PCT levels were drawn on days 0, 1,2 and 3, day 0 being day of surgery. Blood cultures (BC) samples were drawn on days 0 and 3. Statistical analyses were performed to establish median serum PCT values and the interquartile range of the PCT level was reported for each day in μg/L. A two-sample Wilcoxon-Mann-Whitney test was performed to compare the PCT values with the blood culture result to establish if a correlation with a positive blood culture existed.

Results: There were 33 patients on whom burn debridement procedures were done, and 1 patient demised before surgery. The median age was 35.5 years, and 61.8% were male. 4 patients were identified to have comorbidities. There was a trend to higher serum PCT values from day 0 to day 3. The median PCT on day 0 was 3.30 μg/L (IQR 0.78 – 15.10), compared to day 3 PCT which was 5.15μg/L (IQR 1.35 – 18.55). All median values for serum PCT for days 0 to 3 were above the threshold considered to be within normal limits regardless of BC positivity. There was a statistically significant difference in PCT level between positive and negative BC, with a p-value of 0.0087 for Day 3 serum PCT. The median serum PCT on day 0 and day 3 in the subgroup of patients with a negative BC was 1.8 and 0.91 respectively.

Conclusion: Burns patients have a serum PCT that is higher than the threshold considered to be normal even in the absence of sepsis with both the burn injury itself and surgical debridement causing an induction of PCT. There is an association of a high serum PCT level with a positive blood culture in a burns patient post debridement surgery. In these patients interpretation should be performed cautiously to prevent unwarranted antibiotic exposure, a contributor of antibiotic resistance. Serum PCT level in burns patients with or without a positive blood culture is higher than the threshold considered positive in non-burns patients. A higher numerical threshold should be used for this cohort of patients, to aid in diagnosis of infectious complications to augment already existing criteria used to diagnose burn related sepsis. A cut off value could not be determined in this study due to the small sample size