Procalcitonin in the Early Course Post Pediatric Cardiac Surgery

Robert Zant, MD; Christian Stocker, MD, FMH (CH), FCICM; Luregn Jan Schlapbach, MD, FCICM; Sara Mayfield, BHScNurs; Tom Karl, MD, FRACS; Andreas Schibler, MD, FMH (CH), FCICM

Disclosures

Pediatr Crit Care Med. 2016;17(7):624-629. 

In This Article

Discussion

In this prospective study of children requiring surgery for congenital heart disease, we observed higher than normal procalcitonin levels postoperatively. Higher procalcitonin following surgery for congenital heart disease was predictive of MAEs and was highly correlated with postoperative renal failure, length of PICU stay, duration of mechanical ventilation, and duration of inotropic support. Procalcitonin at admission remains a significant risk factor for duration of mechanical ventilation and duration of inotropic support when accounting for the preoperative risk factors that are associated with postoperative procalcitonin elevation.

Over the past years, several studies have been published to assess the diagnostic and prognostic value of procalcitonin after cardiac surgery in adults and have identified variables other than infection having an impact on procalcitonin levels.[10] However, studies in pediatric patients have been limited, due to a small sample size. The association of elevated procalcitonin levels at admission with the LOS in PICU and duration of both inotropic and respiratory support confirms data of previous studies conducted in children.[1,7] In our cohort, procalcitonin levels at admission were significantly higher in children suffering a postoperative MAE and the ROC AUC of procalcitonin was slightly superior to lactate, which is a well-established marker of impaired oxygen delivery to end organs.[11]

Aortic cross clamp time, duration of CPB, and duration of surgery were the intraoperative factors associated with a postoperative increase in procalcitonin.[1,3,7] We suspect that the source of procalcitonin production could be triggered by nonspecific cytokine liberation from the injured tissue damage-associated molecular patterns or insufficient tissue oxygenation including the liver as the main producer of procalcitonin.[2,12–14] The latter thesis is supported by the fact that in our cohort high levels of procalcitonin were significantly associated with serum lactate levels at admission. Similarly, it is known that procalcitonin is significantly increased after pediatric cardiac arrest.[15] Indeed, a number of studies have shown that procalcitonin is a marker of poor outcome in different scenarios including cardiac surgery, post cardiopulmonary resuscitation, shock, and pediatric liver transplantation.[1,7,13,15–18]

This study was not designed to investigate performance of procalcitonin in postoperative infections, and the prevalence of such infections was low. We observed that the patients with the clinical suspicion of infection had already significantly higher procalcitonin values at admission to PICU. Attending clinicians did not have knowledge of the results of the procalcitonin levels during the entire stay in PICU. In only two patients, an infectious agent was isolated. In both cases, very high levels of procalcitonin in the early phase after surgery were observed. Larger prospective studies are needed to define sensitivity and specific of procalcitonin to diagnose invasive infections in children post cardiac surgery.

Early risk assessment after cardiac surgery might play a key role in reducing postoperative complications and death. Procalcitonin, which is increasingly used for routine postoperative infection monitoring, may in addition to lactate help in the early risk stratification of patients after cardiac surgery. It thereby may provide additional early information on the degree of inflammation and tissue damage.[19] Because no defined postoperative cutoff levels are available yet, our study may support clinicians classifying elevated procalcitonin levels after cardiac surgery in children.[10]

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