Different acute-phase response in newborns and infants undergoing surgery

Noninfectious influencers of early-onset sepsis biomarkers

Diagnostic tests for sepsis aim to either detect the infectious agent (such as microbiological cultures) or detect host markers that commonly change in response to an infection (such as C-reactive protein). The latter category of tests has advantages compared to culture-based methods, including a quick turnaround time and in some cases lower requirements for blood samples. They also provide information on the immune response of the host, a critical determinant of clinical outcome. However, they do not always differentiate nonspecific host inflammation from true infection and can inadvertently lead to antibiotic overuse. Multiple noninfectious conditions unique to neonates in the first days after birth can lead to inflammatory marker profiles that mimic those seen among infected infants. Our goal was to review noninfectious conditions and patient characteristics that alter host inflammatory markers commonly used for the diagnosis of early-onset sepsis. Recognizing these conditions can focus the use of biomarkers on patients most likely to benefit while avoiding scenarios that promote false positives. We highlight approaches that may improve biomarker performance and emphasize the need to use patient outcomes, in addition to conventional diagnostic performance analysis, to establish clinical utility.

Procalcitonin versus C-reactive protein: review of kinetics and performance for diagnosis of neonatal sepsis

Procalcitonin (PCT) and C-reactive protein (CRP) are commonly used biomarkers, but their diagnostic advantage for neonatal early-onset (EOS) or late-onset (LOS) sepsis is controversial. In a comprehensive literature review we found significant heterogeneity between studies in sample timing, cut-off values, consideration of blood culture results for sepsis classification, and definition of EOS versus LOS. We identified 39 studies directly comparing PCT with CRP, but only four in very low birth weight (VLBW) neonates. The mean sensitivity for EOS, LOS, and EOS + LOS was 73.6%, 88.9%, and 76.5% for PCT, compared to 65.6%, 77.4%, and 66.4% for CRP, respectively. Mean specificity of PCT and CRP was 82.8% versus 82.7% for EOS, 75.6% versus 81.7% for LOS, and 80.4% versus 91.3% for EOS + LOS. More studies directly comparing both biomarkers for EOS and LOS, especially in extremely and very-low-birth-weight infants, are needed to determine their clinical value for guidance of antibiotic therapy in neonatal sepsis.

Is Procalcitonin Useful in Pediatric Critical Care Patients?

This review examines the use of procalcitonin in different clinical situations in the pediatric patient, with special emphasis on those requiring intensive care. We review the latest articles on its potency as a biomarker in both infectious processes at diagnosis and on the response to treatment.

Kinetics of Procalcitonin in Pediatric Patients on Extracorporeal Membrane Oxygenation

Objectives:

To assess the kinetics of procalcitonin (PCT) and C-reactive protein (CRP) in pediatric patients who required extracorporeal membrane oxygenation (ECMO) and to analyze its relationship with morbidity and mortality.

Patients and methods:

Prospective observational study including pediatric patients who required ECMO. Both PCT and CRP were sequentially drawn before ECMO (P0) and until 72 hours after ECMO.

Results:

A total of 40 patients were recruited. Two cohorts were established based on the value of the P0 PCT (>10 ng/mL). Comparing the kinetics of PCT and CRP in these cohorts, the described curves were the expected for each clinical situation. The cutoff for P0 PCT to predict multiple organ dysfunction syndrome was 2.55 ng/mL (sensibility 83%, specificity 100%). Both PCT and CRP did not predict risk of neurologic sequelae or mortality in any group.

Conclusions:

Procalcitonin does not seem to be modified by ECMO and could be a good biomarker of evolution.

Pediatric Perioperative Stress Responses and Anesthesia

Surgical stress responses cause an array of endocrinological, metabolic and immunological changes in patients. The landmark studies in the 1980s showed that adequate anesthesia dramatically improved the outcomes of pediatric surgical patients by attenuating stress hormonal responses, pointing out the harm of 'inadequate' anesthesia. Subsequent studies questioned the role of administering very high-dose anesthetics to further attenuate stress responses. Here we review the feature of surgical stress responses in pediatric patients including their difference from those in adult patients. Overall, pediatric patients show minimal or no resting energy expenditure change postoperatively. In adult patients, increased resting energy expenditure has been described. Pediatric patients demonstrated robust cortisol and catecholamine responses than adult patients. However, the duration of these surges is often short-lived. Systemic proinflammatory and anti-inflammatory cytokine levels have been measured. Pediatric patients showed less proinflammatory cytokine elevation, but had similar anti-antiinflamatory responses. We also review in detail the immunological changes in response to surgical stress. Based on our current knowledge, we attempted to understand the underlying mechanism how adequate anesthesia dramatically improved the outcome of patients. Although more work is needed to be done, understanding how pediatric patients respond to perioperative stress, and its mechanism and consequence will allow us to direct us into a better, perioperative management in this population.

Preventively enteral application of immunoglobulin enriched colostrums milk can modulate postoperative inflammatory response

Several studies demonstrated acute inflammatory response following traumatic injury. Inflammatory response during surgical interventions was verified by a significant increase of endotoxin plasma levels and a decrease of the endotoxin neutralizing capacity (ENC). However, the incidence of elevated endotoxin levels was significantly higher (89%) than detected bacterial translocation (35%). Thus parts or products of Gram-negative bacteria seem to translocate more easily into the blood circulation than whole bacteria. Along with the bacterial translocation, the inflammatory response correlated directly with the severity of the surgical intervention. In comparison after major and minor surgery Interleukin-6 (IL-6) and C-reactive protein (CRP) was also significantly different. Similar effects in mediator release were shown during endovascular stent graft placement and open surgery in infrarenal aortic aneurysm. Open surgery demonstrated a significant stronger endotoxin translocation and a decrease of ENC. Strategies to prevent translocation seem to be sensible. Colostrum is the first milk produced by the mammary glands within the first days after birth. It contains a complex system of immune factors and has a long history of use in traditional medicine. Placebo-controlled studies verified that prophylactic oral application of immunoglobulin-enriched colostrum milk preparation diminishes perioperative endotoxemia, prevents reduction of ENC and reduces postoperative CRP-levels, suggesting a stabilization of the gut barrier. This effect may be caused by immunoglobulin transportation by the neonatal receptor FcRn of the mucosal epithelium.In conclusion, there is an association of perioperative endotoxemia and the subsequent increase in mediators of the acute phase reaction in surgical patients. A prophylactic oral application of colostrum milk is likely to stabilize the gut barrier i.e. reduces the influx of lipopolysaccharides arising from Gram-negative bacterial pathogens and inhibits enterogenic endotoxemia. This appears to be a major mechanism underlying the therapeutic effect in patients at risk for Gram-negative septic shock.

Time course of C-reactive protein and inflammatory mediators after neonatal surgery

OBJECTIVE

To characterize the perioperative course of C-reactive protein (CRP) and inflammatory mediators in neonates ≤44 weeks' corrected gestational age.

STUDY DESIGN

Prospective study of CRP and inflammatory mediators interleukin (IL)-1β, IL-6, IL-8, IL-10, and tumor necrosis factor-α in 55 neonates undergoing thoracic or abdominal surgery.

RESULTS

In the absence of infection, CRP increased after surgery, peaking on post-operative day 2. The perioperative patterns of CRP differed by diagnosis and inflammatory state. Surgery alone did not cause an increase in CRP because in 13 of 55 infants (24%), CRP remained <1.0 mg/dL at all time points. For thoracic procedures, patent ductus arteriosus ligation showed the least post-operative increase in CRP, and patients undergoing repair of congenital diaphragmatic hernia or tracheoesophageal fistula had a greater response. Abdominal procedures with low CRP response included repair of imperforate anus and pyloric stenosis, while gastroschisis repair and bowel reanastomosis after necrotizing enterocolitis were accompanied by a robust CRP response. IL-6 concentrations peaked on post-operative day 1 and correlated with the post-operative day 2 CRP peak (r=0.398, P=.004). The additional inflammatory mediators measured were not informative.

CONCLUSIONS

The range and time course of perioperative CRP differ by diagnosis. Serial measurements may be more informative than CRP magnitude.

A clinic-biological score for diagnosing early-onset neonatal infection in critically ill preterm infants

OBJECTIVE

To identify the best combination of serum cytokines and clinical parameters to diagnose rapidly early-onset neonatal infection (EONI) in critically ill preterm infants. At birth, most critically ill neonates are receiving broad-spectrum antibiotics pending bacterial culture results, because distinguishing infected from noninfected infants at birth is difficult.

DESIGN

Prospective study.

SETTING

Neonatal intensive care unit in a tertiary care hospital.

PATIENTS

Two hundred thirteen infants, born before 33 wks' gestation, admitted to the neonatal intensive care unit within 6 hrs of life with a presumptive diagnosis of EONI.

INTERVENTION

A presumptive diagnosis of EONI was associated with a 300-μL blood sample to measure six cytokine (interleukin [IL]-1β, IL-6, IL-8, IL-10, IL-12, tumor necrosis factor-α) concentrations, using the cytometric bead array technique.

MEASUREMENTS AND MAIN RESULTS

Of the 213 infants included, 31 had a definite or possible EONI and 182 were not infected. Concentrations of IL-6, IL-8, and IL-10 were significantly increased in infected neonates, in comparison with infants without EONI. In contrast, IL-1β, IL-12, and tumor necrosis factor-α concentrations were not. Logistic regression analyses were performed to construct multivariate predictive models that could distinguish infected from noninfected infants at birth. A clinical score was based on three parameters independently associated with EONI (i.e., interval of >12 hrs between the membranes rupture and delivery, prenatal maternal colonization and mechanical ventilation at birth). This score was compared with scores including clinical parameters and serum cytokines, alone or in combination. The best predictive model combined the three clinical parameters, IL-6 (positive threshold, 300 pg/mL) and IL-8 (positive threshold, 300 pg/mL) concentrations.

CONCLUSION

A predictive model combining serum IL-6 and IL-8 measurements and selected clinical variables could distinguish infected from noninfected preterm infants at birth and should help the clinician in reducing or shortening the unnecessary use of antibiotics.

Use of special education services among children with and without congenital gastrointestinal anomalies

Our objective was to evaluate the relationship between congenital gastrointestinal anomalies requiring neonatal surgery and neurodevelopmental outcome. Among the children born in metropolitan Atlanta during 1982-2001 who survived to age 1 year (N = 762,824), we identified children with congenital gastrointestinal anomalies via linkage with the Metropolitan Atlanta Congenital Defects Program and children who received special education services via linkage with the Special Education Database of Metropolitan Atlanta. Several modest increases in special education service use were observed among children with isolated congenital gastrointestinal anomalies; no association was statistically significant. Among children with Hirschsprung disease, gastroschisis, esophageal atresia, intestinal malrotation, bowel atresia, or imperforate anus who had multiple anomalies, we observed statistically significant increases in special education service use.

Inflammatory response in a rat model of gastroschisis is associated with an increase of NF-kappaB

Babies with gastroschisis have high morbidity, which is associated with inflammatory bowel injury caused by exposure to amniotic fluid. The objective of this study was to identify components of the inflammatory response in the intestine and liver in an experimental model of gastroschisis in rats. The model was surgically created at 18.5 days of gestation. The fetuses were exposed through a hysterotomy and an incision at the right of the umbilicus was made, exposing the fetal bowel. Then, the fetus was placed back into the uterus until term. The bowel in this model had macro- and microscopic characteristics similar to those observed in gastroschisis. The study was conducted on three groups of 20 fetuses each: gastroschisis, control, and sham fetuses. Fetal body, intestine and liver weights and intestine length were measured. IL-1beta, IL-6, IL-10, TNF-alpha, IFN-gamma and NF-kappaB levels were assessed by ELISA. Data were analyzed statistically by ANOVA followed by the Tukey post-test. Gastroschisis fetuses had a decreased intestine length (means +/- SD, 125 +/- 25 vs 216 +/- 13.9; P < 0.005) and increased intestine weight (0.29 +/- 0.05 vs 0.24 +/- 0.04; P < 0.005). Intestine length correlated with liver weight only in gastroschisis fetuses (Pearson's correlation coefficient, r = 0.518, P = 0.019). There were no significant differences in the concentrations of IL-1beta, TNF-alpha or IFN-gamma in the intestine, whereas the concentration of NF-kappaB was increased in both the intestine and liver of fetuses with gastroschisis. These results show that the inflammatory response in the liver and intestine of the rat model of gastroschisis is accompanied by an increase in the amount of NF-kappaB in the intestine and liver.

Ward reduction of gastroschisis in a single stage without general anaesthesia may increase the risk of short-term morbidities: results of a retrospective audit

BACKGROUND

 Ward reduction of gastroschisis in a single stage without the need for general inhalational anaesthesia (ward reduction) has been reported by some authors to be effective and safe. We introduced this practice to our neonatal unit 2 years ago.

AIM

To compare the short-term outcomes of this new practice with the standard procedure of reduction under general anaesthesia (GA).

METHODS

Retrospective case series of all infants with gastroschisis between January 2004 and January 2008.

RESULTS

Twenty-seven infants were managed with the traditional approach and 11 infants underwent ward reduction without GA. Infants in the ward reduction group had an increased frequency for all the three major adverse events (ischemic necrosis of bowel: 27.3% vs. 3.7%, odds ratio (OR) 10.72, 95% confidence interval (CI): 0.72, 159.6; need for total parenteral nutrition (TPN) more than 60 days: 18% vs. 3.7%, OR 4.13, 95% CI: 0.28, 61.55; and unplanned return to theatre: 27.3% vs. 7.4%, OR 3.88, 95% CI: 0.44, 34.08), although none of these events reached statistical significance. There were no significant differences between the groups for the outcomes of time to reach full feeds, duration of hospital stay and number of days on antibiotics.

CONCLUSIONS

These results raise concerns over the role of ward reduction of gastroschisis in a single sitting without the use of GA. Randomised trials with appropriate design and sample size are needed before embracing this method as a standard practice.

Lipopolysaccharide-binding protein, lipopolysaccharide, and soluble CD14 in sepsis of critically ill neonates and children

OBJECTIVE

To compare the diagnostic accuracy of lipopolysaccharide-binding protein (LBP) for sepsis in critically ill neonates and children with the two markers participating in the same inflammatory pathway, lipopolysaccharide and soluble CD14.

DESIGN AND SETTING

Prospective, observational study in a multidisciplinary neonatal and pediatric intensive care unit.

PATIENTS

47 critically ill neonates and 49 critically ill children with systemic inflammatory response syndrome (SIRS) and suspected sepsis, classified into two groups: those with and those without sepsis.

INTERVENTIONS

Serum LBP, lipopolysaccharide, soluble CD14, C-reactive protein, and procalcitonin were measured on 2 consecutive days. The area under the receiver operating characteristic curve (AUC), sensitivity, specificity, and predictive values were evaluated.

RESULTS

AUC for LBP on the first day of suspected infection was 0.97 in neonates aged under 48 h, 0.93 in neonates over 48 h and 0.82 in children. AUCs for lipopolysaccharide and soluble CD14 were 0.77 and 0.74 in neonates under 48 h, 0.53 and 0.76 in neonates over 48 h, and 0.72 and 0.53 in children. AUCs for procalcitonin and C-reactive protein were 0.65 and 0.89 in neonates under 48 h, 0.65 and 0.91 in neonates over 48 h, and 0.76 and 0.69 in children.

CONCLUSIONS

In critically ill neonates and children LBP concentration on the first day of suspected sepsis is a better marker of sepsis than lipopolysaccharide, soluble CD14, procalcitonin, and in neonates younger than 48 h and children, also a better marker than C-reactive protein. Lipopolysaccharide and soluble CD14 are not suitable markers for the differentiation of infectious and noninfectious SIRS.

Different Proinflammatory Cytokine Serum Pattern in Neonate Patients Undergoing Open Heart Surgery. Relevance of IL-8

The purpose of this work was to investigate the clinical significance of serum levels of proinflammatory cytokines in pediatric patients undergoing cardiopulmonary bypass. We divided the patients in two groups: 8 neonates, and 19 non-newborn children. IL-1beta, IL-6, IL-8, and TNF serum levels were quantified before sternotomy, at admission to the PICU (30 min postoperatively), 24 h after the onset of surgery and 3 days after the operation. Surgical cardiac stress elicits significant increments of IL-6, IL-8 and TNF serum concentrations in both neonates and non-neonates, regardless of their preoperative clinical condition. However, in newborns the magnitude of the proinflammatory cytokine increments was, in particular with IL-8, remarkably greater than in older children. Moreover, neonate and non-neonate patients showed clearly disparate patterns of serum concentrations over time of both IL-8 and TNF. There was a marked relationship between IL-8 levels and postoperative morbidity, evaluated by pulmonary dysfunction, days on inotropic support and days of PICU stay in both neonates and non-neonates patients. In contrast, we found no relationship between serum levels of IL-6 and TNF and postoperative clinical data. Newborn and non-newborn patients undergoing cardiopulmonary bypass exhibit dissimilar patterns of proinflammatory cytokines. IL-8 might be implicated in the multiorganic dysfunction related to cardiopulmonary bypass in pediatric patients.

Melatonin reduces oxidative stress in surgical neonates

BACKGROUND/PURPOSE

Cytokines are inflammatory mediators found in the circulation after surgery. Newborns have less protection against oxidation and are very susceptible to free radical oxidative damage. Melatonin has been reported recently to reduce oxidative stress in neonates with sepsis, asphyxia, and respiratory distress. The aim of this study has been to determine if melatonin would lower interleukin (IL)-6, IL-8, tumor necrosis factor alpha (TNF-alpha) and nitrite/nitrate (NOx) levels and modify serum inflammation parameters, improving the clinical course of surgical neonates.

METHODS

Ten newborns (group 1), 5 with surgical malformations and respiratory distress (group 1a) and 5 with isolated abdominal surgical malformations (group 1b) received a total of 10 doses of melatonin (10 mg/kg) at defined times interval for 72 hours. The treatment was started within 3 hours after the end of surgery. Ten surgical neonates (group 2), did not receive melatonin. Twenty healthy neonates (group 3) served as control. Blood samples were collected at the end of operation; before treatment with the antioxidant; and 24 hours 72 hours, and 7 days after start of treatment with melatonin or placebo, respectively.

RESULTS

Postoperative value of cytokines and NOx levels of groups 1 and 2 were significantly higher than group 3. Compared with group 1b, group 2 displayed significantly higher cytokines and NOx levels at 24 hours, 72 hours, and at 7 days. In group 1a the immediate postoperative values of cytokines were significantly higher than group 1b and group 2, but a significant improvement was observed after administration of melatonin with significantly lower levels of IL-6 and IL-8 with respect to group 2. An improvement of clinical outcome was observed by progressive reduction of clinical parameters of inflammation.

CONCLUSIONS

Melatonin reduces cytokines and NOx levels showing potent antioxidant properties with improvement in clinical outcome. Further studies are warranted to define, on larger numbers, the role of melatonin in surgical patients.

Airway smooth muscle changes in the nitrofen-induced congenital diaphragmatic hernia rat model

In the fetal rat, nitrofen induces congenital diaphragmatic hernia (CDH) and pulmonary vascular remodeling similar to what is observed in the human condition. Airway hyperactivity is common in infants with CDH and attributed to the ventilator-induced airway damage. The purpose of this study was to test the hypothesis that airway smooth muscle mechanical properties are altered in the nitrofen-induced CDH rat model. Lungs from nitrofen-exposed fetuses with hernias (CDH) or intact diaphragm (nitrofen) and untreated fetuses (control) were studied on gestation d 21. The left intrapulmonary artery and bronchi were removed and mounted on a wire myograph, and lung expression, content, and immunolocalization of cyclooxygenases COX-1 and COX-2 were evaluated. Pulmonary artery muscle in the CDH group had significantly (p < 0.01) lower force generation compared with control and nitrofen groups. In contrast, the same generation bronchial smooth muscle of the CDH and nitrofen groups developed higher force compared with control. Whereas no differences were found in endothelium-dependent pulmonary vascular muscle tone, the epithelium-dependent airway muscle relaxation was significantly decreased (p < 0.01) in the CDH and nitrofen groups. The lung mRNA levels of COX-1 and COX-2 were increased in the CDH and nitrofen groups. COX-1 vascular and airway immunostaining, as well as COX-1 and COX-2 lung protein content, were increased in the CDH group. This is the first report of airway smooth muscle abnormalities in the nitrofen-induced fetal rat model of CDH. We speculate that congenital airway muscle changes may be present in the human form of this disease.