Immediate postinjury procalcitonin levels related to final survival

Introduction

Procalcitonin (PCT) levels have been proved to be a very useful marker not only in severe microbial sepsis but also in SIRS and MOFS. Severe polytrauma is one typical example of SIRS without microbial infection, at least during the first days. High PCT levels are often seen in multiple trauma, sometimes higher than that seen in septic shock. The prognostic meaning of these high PCT levels is practically unknown and has to be further investigated.

Objective

To assess the PCT levels during the first post-traumatic days and correlate them with: the final outcome of the patient, the injury severity score (ISS) and the expected mortality, and lactic acid as a marker of tissue perfusion.

Materials and methods

Over a period of 12 months (2003–2004) 42 consecutive patients older than 18 years who were admitted to the ICU of the KAT General Hospital for an expected stay > 24 hours were prospectively included in the study. The study protocol was approved by the local ethics committee. Informed consent was obtained from the next of kin of unconscious patients. All patients (mean age 27 years old) were intubated and mechanically ventilated. From each enrolled patient blood was withdrawn at the end of the first, second and third day to assess the PCT and lactic acid levels. The modified ISS to predict mortality, the kind and the severity of the injuries, and their final outcome were also registered. The patients were divided into group A, 23 patients who survived, and group B, 19 patients who finally died.

Results

The patients of group A had a mean ISS of 32.87 with expected mortality 30.77%, and group B had ISS 35.45 with expected mortality 34.57%. In group A the mean PCT levels of the first day were 5.62 ng/dl, the second day 3.69 ng/dl and the third day 2.13 ng/dl. There was a smooth decrease of the PCT over the days and the difference was statistically significant (P = 0.05). In group B the first day mean values were 3.03 ng/dl, the second day 3.65 ng/dl and the third day 1.12 ng/dl. There was a sudden increase over the second day and a statistically significant decreased over the third day (P = 0.01). There were no correlations between the PCT levels, the lactic acid levels, the ISS and the expected mortality.

Discussion

As seen in the literature, the patients who die from trauma have higher PCT levels. But there are no comments on the possible meaning of the value fluctuation during the first post-traumatic days. In our study it seems that the initial PCT levels were lower in the patients who died than in the patients who survived. In group A the decrease of the PCT was linear over all three days. But in the patients who died the PCT increased suddenly the second day followed by a steep decrease on the third day much lower than that seen in group A.

There is no known explanation of this phenomenon. One could suggest that this is due to an immunity system malfunction that allows patients to die late after a severe trauma. That has to be proved.

Conclusion

It seems that the high initial levels of PCT do not have such a great prognostic value as has the alteration of the PCT levels seen later during the next days.