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

Results

Baseline Characteristics

A total of 221 patients who as a group had undergone 232 operations were included. The median age of the study group was 44 months (range, 1 d to 16.9 yr). Preoperative mean Basic, and Comprehensive Aristotle Complexity Scores were 7.4 (3–14.5) and 9.4 (3–21); the preoperative mean Risk Adjusted Congenital Heart Surgery Score in our cohort was 1,928 (1,609–1,991). Preoperative risk factors were present in 43 (19%) of all included patients (Table 1). Eight patients (3%) had more than one preoperative risk factor. Indications for cardiac surgery are summarized in Table 2. Five of 221 patients (2%) suffered a MAE: one patient had a cardiac arrest, one patient required emergency extracorporeal life support, and three patients died within 3 months of cardiac surgery.

Overview Procalcitonin Levels

The median procalcitonin level of all patients after cardiac surgery was 0.01 ng/mL (0.3) at admission to PICU, reaching the postoperative peak of 0.8 ng/mL (2.1) at POD1 with a decline to 0.7 ng/mL (2.2) on POD2. Simultaneously measured median levels for serum lactate were 1.4 mmol/L (0.9) at admission, 1.4 mmol/L (0.7) for POD1, and 1.1 mmol/L (0.7) for POD2. The procalcitonin values at admission and on POD1 were not associated with age (p = 0.52 and 0.38, respectively) (Fig. 1). Preoperative risk factors associated with procalcitonin elevation at admission were mechanical ventilation prior to surgery (p = 0.001) and myocardial dysfunction (p = 0.002). There was no significant difference in procalcitonin values at admission in patients with and without chromosomal/syndromic abnormality (p = 0.57). Procalcitonin concentrations at admission were not associated with any specific cardiac condition (Fig. 2).

Figure 1.

Procalcitonin values at admission to PICU and on postoperative day 1 in relation to age.

Figure 2.

Procalcitonin values at admission to PICU in relation to indication for surgery. The broken line indicates a cut-off level of 0.3 ng/mL. ASD = atrial septal defect, AoS: aortic valve stenosis, coarctation = coarctation of the aorta, DORV = double outlet right ventricle, HLH = hypoplastic left heart syndrome, LVOTO = left ventricular outflow tract obstruction, PA = pulmonary atresia, PR = pulmonary regurgitation, PS = pulmonary stenosis, TAPVD = totally anomalous pulmonary venous drainage, TGA = transposition of the great arteries, ToF = Tetralogy of Fallot; VSD = ventricular septal defect.

Procalcitonin and CPB

In patients with CPB, the median procalcitonin level at admission was 0.01 ng/mL (0.3) and on POD1 was 0.8 ng/mL (1.9) (p = 0.24). In patients without CBP, the procalcitonin level at admission was 0.01 (0.1) and on POD1 was 0.5 ng/mL (1.3). Levels of procalcitonin at admission correlated significantly with the duration of CPB (p < 0.001), cross-clamp time (p = 0.015), and serum lactate at admission (p < 0.001). No significant difference in procalcitonin levels between patients operated with or without CBP was found for POD0, POD1, and POD2 (p = 0.24, 0.41, and 0.52, respectively).

Procalcitonin and Outcome

The median procalcitonin level at admission of the five patients suffering a MAE was significantly higher, 0.3 ng/mL (0.8), than patients without a MAE with a median level of 0.01 ng/mL (0.19) (p = 0.04). The area under the ROC curve for procalcitonin at admission as a predictor for MAE was 0.74 (95% CI, 0.52–0.96), compared with the AUC ROC for lactate at admission of 0.72 (95% CI, 0.54–0.92). Furthermore, procalcitonin levels at admission correlated significantly with the LOS in the PICU (p = 0.005), time on mechanical ventilation (p = 0.03), and duration of inotropic support (p = 0.02). procalcitonin at admission was significantly correlated with preoperative disease severity and intraoperative variables (cross-clamp time and duration on CBP). Linear regression adjusting for mechanical ventilation and cardiac dysfunction preoperatively confirmed that higher procalcitonin was independently predictive for both time on mechanical ventilation and duration of inotropic support (Table 3). The median procalcitonin levels at admission in patients with postoperative renal failure requiring temporary dialysis was with 1 ng/mL (1.7), which was significantly higher than in patients without postoperative renal failure (p = 0.01). In the early phase after cardiac surgery, procalcitonin clearance from POD1 to POD2 was not significantly different in patients with and without postoperative renal failure (p = 0.16). Table 4 summarizes procalcitonin at admission as a prognostic parameter, including MAE, postoperative renal failure requiring temporary dialysis and values above the 90th percentile for LOS in the PICU, time on mechanical ventilation and inotropic support.

Exploratory Analyses in Patients With Postoperative Infections

In nine patients (3.9%), invasive infection was suspected in the first three postoperative days, prompting initiation of broad-spectrum antibiotics. Compared with the entire study cohort, these patients with suspected infection had already significantly higher procalcitonin levels at admission to PICU (p = 0.003) with a median level of 1.0 ng/mL (1.7). In only two patients with assumed infection growth of either Staphylococcus hominis (ascites) or Moraxella catarrhalis (endotracheal aspirate) was demonstrated.

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