Background-Procalcitonin has been advocated as a marker of bacterial infection.Objective-To evaluate diagnostic markers of infection in critically ill children, comparing procalcitonin with C reactive protein and leucocyte count in a paediatric intensive care unit (PICU). Methods-Procalcitonin, C reactive protein, and leucocyte count were measured in 175 children, median age 16 months, on admission to the PICU. Patients were classified as: non-infected controls (43); viral infection (14); localised bacterial infection without shock (25); bacterial meningitis/encephalitis (10); or septic shock (77). Six children with "presumed septic shock" (without suYcient evidence of infection) were analysed separately. Optimum sensitivity, specificity, predictive values, and area under the receiver operating characteristic (ROC) curve were evaluated. Results-Admission procalcitonin was significantly higher in children with septic shock (median 94.6; range 3.3-759.8 ng/ ml), compared with localised bacterial infection (2.9; 0-24.3 ng/ml), viral infection (0.8; 0-4.4 ng/ml), and non-infected controls (0; 0-4.9 ng/ml). Children with bacterial meningitis had a median procalcitonin of 25.5 (7.2-118.4 ng/ml). Area under the ROC curve was 0.96 for procalcitonin, 0.83 for C reactive protein, and 0.51 for leucocyte count. Cut oV concentrations for optimum prediction of septic shock were: procalcitonin > 20 ng/ml and C reactive protein > 50 mg/litre. A procalcitonin concentration > 2 ng/ml identified all patients with bacterial meningitis or septic shock. Conclusion-In critically ill children the admission procalcitonin concentration is a better diagnostic marker of infection than C reactive protein or leucocyte count. A procalcitonin concentration of 2 ng/ml might be useful in diVerentiating severe bacterial disease in infants and children. (Arch Dis Child 1999;81:417-421)

Objectives-To evaluate the ability of clinicians involved in the provision of paediatric intensive care to estimate cardiac index in ventilated children, based on physical examination and clinical and bedside laboratory data. Methods-Clinicians were exposed to all available haemodynamic and laboratory data for each patient, allowed to make a physical examination, and asked to first categorise cardiac index as high, high to normal, low to normal, or low, and then to quantify this further with a numerical estimate. Cardiac index was measured simultaneously by femoral artery thermodilution (coeYcient of variation 5.37%). One hundred and twelve estimates were made by 27 clinicians on 36 patients (median age 34.5 months). Results-Measured cardiac index ranged from 1.39 to 6.84 l/min/m 2 . Overall, there was poor correlation categorically ( statistic 0.09, weighted 0.169) and numerically (r = 0.24, 95% confidence interval 0.06 to 0.41 ), although some variation was seen among the various levels of seniority. Conclusion-Assuming that objective measurement, and hence manipulation, of haemodynamic variables may improve outcome, these findings support the need for a safe, accurate, and repeatable technique for measurement of cardiac index in children who are critically ill.

Background-Functional adrenal insuYciency has been documented in critically ill adults. Objective-To document the incidence of adrenal insuYciency in children with septic shock, and to evaluate its eVect on catecholamine requirements, duration of intensive care, and mortality. Setting-Sixteen-bed paediatric intensive care unit in a university hospital. Methods-Thirty three children with septic shock were enrolled. Adrenal function was assessed by the maximum cortisol response after synthetic adrenocorticotropin stimulation (short Synacthen test). InsuYciency was defined as a post-Synacthen cortisol increment < 200 nmol/l. Results-Overall mortality was 33%. The incidence of adrenal insuYciency was 52% and children with adrenal insuYciency were significantly older and tended to have higher paediatric risk of mortality scores. They also required higher dose vasopressors for haemodynamic stability. In the survivor group, those with adrenal insuYciency needed a longer period of inotropic support than those with normal function (median, 3 v 2 days), but there was no significant diVerence in duration of ventilation (median, 4 days for each group) or length of stay (median, 5 v 4 days). Mortality was not significantly greater in children with adrenal insuYciency than in those with adequate adrenal function (6 of 17 v 5 of 16, respectively). Conclusion-Adrenal insuYciency is common in children with septic shock. It is associated with an increased vasopressor requirement and duration of shock. (Arch Dis Child 1999;80:51-55)

The admission PCT, like TNF and IL-10, is related to the severity of organ failure and mortality in children with septic shock. A fall in PCT after 24 hrs of treatment may have favorable prognostic significance.

Hypofibrinogenemia and inadequate heparin reversal are 2 important factors contributing to clot strength and perioperative hemorrhage after pediatric CPB. TEG may be a useful tool for predicting and guiding early treatment of mediastinal bleeding in this group.