Association between serum procalcitonin levels and outcomes of patients admitted to two tertiary paediatric intensive care units in Bloemfontein: A retrospective analytical study.

Background: Procalcitonin (PCT) is used in the diagnosis of sepsis. Its capability as a prognostic marker is unclear. The association between PCT and paediatric intensive care unit (PICU) outcomes has not been investigated in the South African setting.

Objectives: To determine the association between admission PCT, and trends within 72 hours of admission, and outcomes of patients admitted to the PICU at two tertiary academic hospitals.

Methods: The study was a two-year, double centre, retrospective, analytical cross-sectional medical record review.

Results: A total of 381 participants were included in the study; 55 died and 220 required mechanical ventilation. Non-survivors had a higher median admission PCT than survivors (p<0.0001, 95% confidence interval (CI) 1.28 - 15.12). Non-survivors had a higher median PCT at 48 - 72 hours than survivors (p<0.0001, 95% CI 2.50 - 21.72). Non-survivors had less of a median decrease in PCT than survivors (p=0.22, 95% CI -0.59 - 4.72). The area under the receiver operating characteristics curve (AUROCC) for admission PCT to discriminate for mortality was 0.6702 and for the 48 - 72 hour PCT it was 0.7369. There was a positive correlation between PCT and number of ventilator days (Spearman correlation co-efficient =0.1477, p=0.0138). There was no correlation between the length of PICU stay and admission PCT (p=0.7579) or PCT change (p=0.2034).

Conclusion: Single PCT measurements display some ability to discriminate for PICU mortality. Serial PCT measurements provide greater prognostic information. Non-survivors had a significantly greater median admission PCT, median PCT at 48 - 72 hours and a lower median PCT decrease than survivors.

Contribution of the study: This study clarifies the role and limitations of procalcitonin measurements and trends in PICU outcomes.