The clinical implications of the systemic inflammatory reaction related to cardiac operations in children

Bioactive adrenomedullin (bio-ADM) is associated with endothelial dysfunction in infants and children with complex congenital heart disease undergoing open-heart surgery on cardiopulmonary bypass

OBJECTIVES

Children with congenital heart disease (CHD) undergoing cardiac surgery on cardiopulmonary bypass (CPB) are at risk for systemic inflammation leading to endothelial dysfunction associated with increased morbidity. Bioactive adrenomedullin (bio-ADM) is a peptide regulating vascular tone and endothelial permeability. The aim of this study was to evaluate the dynamics of plasma bio-ADM in this patient cohort and its role in capillary leak.

METHODS

Plasma samples from 73 pediatric CHD patients were collected for bio-ADM measurement at five different timepoints (TP) in the pre-, intra-, and post-operative period. The primary endpoint was a net increase in bio-ADM levels after surgery on CPB. Secondary endpoints included association of bio-ADM levels with clinical signs for endothelial dysfunction.

RESULTS

Bio-ADM levels increased after surgery on CPB from pre-operative median of 12 pg/mL (IQR [interquartile range] 12.0-14.8 pg/mL) to a maximum post-operative median of 48.8 pg/mL (IQR 34.5-69.6 pg/mL, p<0.001). Bio-ADM concentrations correlated positively with post-operative volume balance, (r=0.341; p=0.005), increased demand for vasoactive medication (duration: r=0.415; p<0.001; quantity: TP3: r=0.415, p<0.001; TP4: r=0.414, p<0.001), and hydrocortisone treatment for vasoplegia (bio-ADM median [IQR]:129.1 [55.4-139.2] pg/mL vs. 37.9 [25.2-64.6] pg/mL; p=0.034). Patients who required pleural effusion drainage revealed higher bio-ADM levels compared to those who did not (median [IQR]: 66.4 [55.4-90.9] pg/mL vs. 40.2 [28.2-57.0] pg/mL; p<0.001).

CONCLUSIONS

Bio-ADM is elevated in children after cardiac surgery and higher levels correlate with clinical signs of capillary leakage. The peptide should be considered as biomarker for endothelial dysfunction and as potential therapeutic target in this indication.

Haemodynamic effects of prophylactic post-operative hydrocortisone following cardiopulmonary bypass in neonates undergoing cardiac surgery

Multiple studies have endeavoured to define the role of steroids in paediatric congenital heart surgery; however, steroid utilisation remains haphazard. In September, 2017, our institution implemented a protocol requiring that all neonates undergoing cardiac surgery with the use of cardiopulmonary bypass receive a five-day post-operative hydrocortisone taper. This single-centre retrospective study was designed to test the hypothesis that routine post-operative hydrocortisone administration reduces the incidence of capillary leak syndrome, leads to favourable postoperative fluid balance, and less inotropic support in the early post-operative period. Data were gathered on all term neonates who underwent cardiac surgery with the use of bypass between September, 2015 and 2019. Subjects who were unable to separate from bypass, required long-term dialysis, or long-term mechanical ventilation were excluded. Seventy-five patients met eligibility criteria (non-hydrocortisone group = 52; hydrocortisone group = 23). For post-operative days 0-4, we did not observe a significant difference in net fluid balance or vasoactive inotropic score between study groups. Similarly, we saw no major difference in secondary clinical outcomes (post-operative duration of mechanical ventilation, ICU/hospital length of stay, and time from surgery to initiation of enteral feeds). In contrast to prior analyses, our study was unable to demonstrate a significant difference in net fluid balance or vasoactive inotropic score with the administration of a tapered post-operative hydrocortisone regimen. Similarly, we saw no effect on secondary clinical outcomes. Further long-term randomised control studies are necessary to validate the potential clinical benefit of utilising steroids in paediatric cardiac surgery, especially in the more fragile neonatal population.

Biomarker-based risk model to predict persistent multiple organ dysfunctions after congenital heart surgery: a prospective observational cohort study

BACKGROUND

Multiple organ dysfunction syndrome (MODS) is an important cause of post-operative morbidity and mortality for children undergoing cardiac surgery requiring cardiopulmonary bypass (CPB). Dysregulated inflammation is widely regarded as a key contributor to bypass-related MODS pathobiology, with considerable overlap of pathways associated with septic shock. The pediatric sepsis biomarker risk model (PERSEVERE) is comprised of seven protein biomarkers of inflammation and reliably predicts baseline risk of mortality and organ dysfunction among critically ill children with septic shock. We aimed to determine if PERSEVERE biomarkers and clinical data could be combined to derive a new model to assess the risk of persistent CPB-related MODS in the early post-operative period.

METHODS

This study included 306 patients < 18 years old admitted to a pediatric cardiac ICU after surgery requiring cardiopulmonary bypass (CPB) for congenital heart disease. Persistent MODS, defined as dysfunction of two or more organ systems on postoperative day 5, was the primary outcome. PERSEVERE biomarkers were collected 4 and 12 h after CPB. Classification and regression tree methodology were used to derive a model to assess the risk of persistent MODS.

RESULTS

The optimal model containing interleukin-8 (IL-8), chemokine ligand 3 (CCL3), and age as predictor variables had an area under the receiver operating characteristic curve (AUROC) of 0.86 (0.81-0.91) for differentiating those with or without persistent MODS and a negative predictive value of 99% (95-100). Ten-fold cross-validation of the model yielded a corrected AUROC of 0.75 (0.68-0.84).

CONCLUSIONS

We present a novel risk prediction model to assess the risk for development of multiple organ dysfunction after pediatric cardiac surgery requiring CPB. Pending prospective validation, our model may facilitate identification of a high-risk cohort to direct interventions and studies aimed at improving outcomes via mitigation of post-operative organ dysfunction.

The cardioprotective and anti-inflammatory effect of inhaled nitric oxide during Fontan surgery in patients with single ventricle congenital heart defects: a prospective randomized study

Background

Fontan surgery with cardiopulmonary bypass (CPB) causes tremendous systemic stress and inflammatory responses, affecting postoperative organ function, morbidity, and mortality. Although this reaction triggers partially protective anti-inflammatory responses, it is harmful in patients with single ventricle congenital heart defects. Despite decades of research, an effective anti-inflammatory and stress defense strategy is lacking. This study investigated the influence of inhaled nitric oxide (NO) during CPB on early clinical results, including the duration of postoperative respiratory support as a primary outcome and a panel of laboratory analytes.

Methods

In this study, 115 patients were randomized to the Fontan-NO group (n = 48) and the Fontan group (n = 49). Eighteen patients were excluded from the study. The Fontan-NO group received NO inhaled directly into the oxygenator during CPB. Clinical data were collected, and blood samples were drawn for analysis at repeated intervals. Multiplex assays were used to analyze a proteome profile of molecules involved in stress response, inflammation, metabolic reactions, as well as heart and lung protection.

Results

Fontan-NO patients had significantly shorter respiratory support time with a median of 9.3 h (7.0; 13,2) vs 13.9 h (3.7; 18.5) by the absolute difference of 4.6 h [95% confidence interval, − 30.9 to 12.3; (p = 0.03)]. In addition, they have a shorter time in intensive care (p = 0.04) and lower pulmonary artery pressure after CPB discontinuation (p = 0.04), 4 h (p = 0.03) and 8 h (p = 0.03) after surgery. Fontan-NO patients also had a lower concentration of lactates (p = 0.04) and glucose after separation from CPB (p = 0.02) and lower catecholamine index (p = 0.042). Plasma factors analysis has shown a significantly higher concentration of interleukin-10, and a lower concentration of interleukin-6, interleukin-8, interleukin-1β, pentraxin, matrix metalloproteinase-8, troponin-I, creatine kinase myocardial band (CK-MB), and insulin in Fontan-NO group.

Conclusions

NO inhaled into the oxygenator during CPB can improve short-term clinical outcomes. It shortens intubation time and intensive care time. It reduces inflammatory response, improves myocardial and lung protection, and diminishes metabolic stress in patients with a single ventricle undergoing Fontan surgery.

Trial registration number: The trial was preregistered, supervised, and supported by The Polish National Science Center (NCN/01/B/NZ5/04246).

Supplementary Information

The online version contains supplementary material available at 10.1186/s40560-022-00639-y.

Uni-ventricular palliation vs. bi-ventricular repair: differential inflammatory response

Background

To examine whether uni-ventricular palliation (UVP) and bi-ventricular repair (BVR) result in a different pattern of systemic inflammatory response to pediatric cardiac surgery with extra-corporeal circulation (ECC).

Methods

In 20 children (median age 39.5 months) undergoing either UVP (n = 12) or BVR (n = 8), plasma levels of the inflammatory cytokines TNF-α, IL-6, IL-10, and IL-12 and of procalcitonin (PCT), were measured before, during and after open cardiac surgery up to postoperative day (POD) 10.

Results

Epidemiologic, operative- and outcome variables were similar in both groups but post-operative central venous pressure that was higher in UVP. In the whole cohort, the inflammatory response was characterized by an early important, significant and parallel increase of IL-6 and IL-10 that reached their peak values either at the end of ECC (IL-10) or 4 h postoperatively (IL-6), respectively and by a significant and parallel decrease of TNF-α and IL-12 levels after connection to ECC, followed by a bi-phasic significant increase with a first peak 4 h after ECC and a second at POD 10, respectively. Patients after UVP showed a shift of the cytokine balance with lower IL-6- (p = 0.01) after connection to ECC, lower early post-operative TNF-α - (p = 0.02) and IL-12- (p = 0.04) concentrations and lower TNF-α/IL-10-ratio (p = 0.03) as compared with patients with BVR. Levels of PCT were similar in both groups.

Conclusions

UVP is associated with an anti-inflammatory shift of the inflammatory response to cardiac surgery that might be related to the particular hemodynamic situation of patients with UVP.

Patterns and Determinants of Change in Cortisol Levels and Thyroid Function as a Function of Cardiac Risk in Children Undergoing Cardiac Surgery

Background

Children undergoing cardiac surgery with cardiopulmonary bypass (CPB) are exposed to the risk of hormonal imbalances resulting from acute stress, which may eventually result in high postoperative mortality and morbidity.

Objective

We assessed adrenal and thyroid hormonal changes and their determinants following cardiac surgery in children and explored their prognostic value in predicting cardiac outcomes. Study Design and Methods. A prospective cohort study was conducted at King Abdulaziz University Hospital (KAUH), between 2017 and 2018. The study involved 46 children aged 14 years or younger who underwent elective cardiac surgery with cardiopulmonary bypass. Serum levels of cortisol, TSH, fT3, and fT4 were measured preoperatively and 24, 48, and 72 hours after surgery. The cardiac risk was assessed using the risk adjustment for congenital heart surgery (RACHS) scale. A composite cardiovascular outcome was analyzed as a numerical variable and calculated as the number of cardiovascular events.

Results

Overall, the changes in thyroid function parameters resulted in a U-shaped curve, while cortisol levels yielded a bell-shaped curve. The most significant changes occurred at 24 hours postop, including a decrease in mean TSH by 2.08 μIU/L (p < 0.001), fT3 by 2.39 pmol/L (p < 0.001), and fT4 by 2.45 pmol/L (p < 0.001) and an increase in cortisol levels by 406.48 nmol/L (p < 0.001) with respect to the baseline. Cortisol concentration peaked higher and recovered slower among patients with high cardiac risk than their counterparts. Cardiovascular outcomes were independently predicted by the extent of the decline in fT4 and TSH at 48 and 72 hours postop, with reference to the baseline, and by the cortisol level at 24 h postop, independent of the baseline, besides the RACHS category.

Conclusion

Cardiac surgery among children yields a high adrenocortical response and a high incidence of nonthyroidal illness syndrome, increasing cardiovascular risk. A preventive management strategy involves improving surgical techniques to minimize trauma-related stress.

Neutrophil-Lymphocyte Ratio in Congenital Heart Surgery: What Is Known and What Is New?

Operative mortality after repair of congenital heart disease has improved dramatically over the past few decades. Nevertheless, there is always room for the additional mitigation of complications and mortality. Being able to anticipate adverse outcomes is clearly important, especially when using low-cost and easily accessible resources. The neutrophil-lymphocyte ratio (NLR) is defined as the ratio of the absolute neutrophil to lymphocyte count, which can be easily measured using a regular white blood cell count. Recently, preoperative NLR has been shown to be a predictor of outcomes in patients undergoing congenital heart surgery. Although it presented promising results, there are still many gaps to be filled like the normal value for children, the ideal cutoff value to predict adverse outcomes, the wide variation and its correlation with other biomarkers, and if it is a modifiable risk factor. The aim of this review is to understand the prognostic value of preoperative NLR as a biomarker predictor of outcomes in patients undergoing congenital heart surgery based on previous clinical studies and to propose future directions in order to solve the above-mentioned questions.

Diagnosis and management of junctional ectopic tachycardia in children

Junctional ectopic tachycardia (JET) is more common in its postoperative form. A thorough understanding of its etiology, pathophysiology, and management strategies is essential. Classically, postoperative JET is considered to arise from surgical trauma. Genetic susceptibility and an intrinsic morphologic/functional defect in the conduction system inherent in congenital heart diseases likely play a significant role. The devastating effects on postoperative hemodynamics warrant prompt attention. A multipronged management approach with general measures, pharmacotherapy, and pacing has decreased morbidity and mortality. Amiodarone and procainamide remain the preferred drugs, while ivabradine appears promising. Carefully planned randomized trials can go a long way in developing a systematic management protocol for postoperative JET.

Preoperative Neutrophil-Lymphocyte Ratio Can Predict Outcomes for Patients Undergoing Tetralogy of Fallot Repair

INTRODUCTION

Elevated neutrophil-lymphocyte ratio (NLR) has been associated with poorer outcomes in cyanotic patients undergoing single ventricle palliation. Little is known about this biomarker on patients with tetralogy of Fallot (TOF), the most common cyanotic congenital heart disease. Our objective is to study the impact of preoperative NLR on outcomes of TOF patients undergoing total repair.

METHODS

This retrospective study included 116 consecutive patients between January 2014 and December 2018. Preoperative NLR was measured from the last complete blood count test before the surgery. Using the cutoff value of 0.80, according to the receiver-operating characteristic (ROC) curve, the sample was divided into two groups (NLR < 0.80 and ≥ 0.80). The primary endpoint was hospital length of stay (LOS).

RESULTS

ROC curves showed that higher preoperative NLR was associated with longer hospital LOS, with an area under the curve of 0.801±0.040 (95% confidence interval 0.722 - 0.879; P<0.001). High preoperative NLR was also associated with long intensive care unit (ICU) LOS (P=0.035). Preoperative NLR predicted longer hospital LOS with a sensitivity of 63% and a specificity of 81.4%.

CONCLUSION

Higher preoperative NLR was associated with long ICU and hospital LOS in patients undergoing TOF repair.

Clinical and Laboratory Predictors for the Development of Low Cardiac Output Syndrome in Infants Undergoing Cardiopulmonary Bypass: A Pilot Study

Cardiac surgery employing cardiopulmonary bypass exposes infants to a high risk of morbidity and mortality. The objective of this study was to assess the utility of clinical and laboratory variables to predict the development of low cardiac output syndrome, a frequent complication following cardiac surgery in infants. We performed a prospective observational study in the pediatric cardiovascular ICU in an academic children’s hospital. Thirty-one patients with congenital heart disease were included. Serum levels of nucleosomes and a panel of 20 cytokines were measured at six time points in the perioperative period. Cardiopulmonary bypass patients were characterized by increased levels of interleukin-10, -6, and -1α upon admission to the ICU compared to non-bypass cardiac patients. Patients developing low cardiac output syndrome endured longer aortic cross-clamp time and required greater inotropic support at 12 h postoperatively compared to bypass patients not developing the condition. Higher preoperative interleukin-10 levels and 24 h postoperative interleukin-8 levels were associated with low cardiac output syndrome. Receiver operating characteristic curve analysis demonstrated a moderate capability of aortic cross-clamp duration to predict low cardiac output syndrome but not IL-8. In conclusion, low cardiac output syndrome was best predicted in our patient population by the surgical metric of aortic cross-clamp duration.

Early postoperative arrhythmias in patients undergoing congenital heart surgery

Background

This study aims to evaluate early postoperative arrhythmias in children undergoing congenital cardiac surgery.

Methods

A total of 670 pediatric patients (355 males, 315 females; median age: 4 months; range, 1 day to 18 years) who underwent cardiac surgery due to congenital heart defects between December 2018 and November 2019 were included. The rate of postoperative arrhythmias, diagnosis, potential risk factors, and management strategies were evaluated. Multivariate regression analysis was used to identify significant factors of development of postoperative arrhythmias.

Results

Tachyarrhythmia was detected in 54 patients (8.1%), and the most common tachyarrhythmia was junctional ectopic tachycardia. Medical treatment was required in 25/38 (66%) of junctional ectopic tachycardia patients. Amiodarone was initiated in 18, dexmedetomidine in five, and flecainide + amiodarone in two of the patients. Different degrees of atrioventricular block were observed in 30 patients (4.5%). In 12 patients, permanent pacemakers were implanted during hospitalization. Age at the time of surgery under one-year-old, high inotropic scores, prolonged operation time, and high Aristotele"s scores were independent risk factors associated with early postoperative arrhythmia (p<0.05). The most common operations associated with early postoperative arrhythmia were left ventricular outflow tract, (6/20, 30%), complete atrioventricular septal defect (13/53, 24%), and tetralogy of Fallot (20/134, 14%) surgeries.

Conclusion

Cardiac arrhythmias are common in the early period after congenital heart surgery in children. The diagnosis and frequency of arrhythmias may vary according to different surgical procedures.

Myocardial Expression of Estrogen Receptor-mRNA Is Associated With Lower Markers of Post-operative Organ Damage in Young Patients With Congenital Cardiac Defect

Background: Estrogen receptors (ERs) relate to cardio-protection in adults, but their role in younger patients is not known. We aimed to assess the myocardial expression of ERα- and ERβ- mRNA in young patients with congenital cardiac disease and to analyze their putative protective role. Patients and Methods: Twenty children and young adults (seven females and 13 males) with a median age of 13.8 years (interquartile range: 12.3 years) were enrolled in this prospective study. The myocardial expression of ER-mRNA and genes involved in inflammation, growth, and stress response was assessed by real-time PCR and was correlated to post-operative (po) outcome. Results: ER-mRNA was detected in the myocardium of all patients, independently of gender and age. The expression of ER-mRNA correlated with that of mRNA coding for brain natriuretic peptide and for all cytokines tested. A higher ERα-mRNA expression correlated with lower troponin T concentrations at 24 h po (p = 0.032), higher PaO₂/FiO₂ ratio at 4 h po (p = 0.059), lower fluid retention at 4 h po (p = 0.048), and lower aspartate aminotransferase (AST) levels at 24 h po (p = 0.047). A higher ERβ-mRNA expression was also correlated with lower fluid retention at 24 h po (p = 0.048). Patients in whom the levels of ERα- and ERβ-mRNA were >P50 had lower troponin T (p = 0.003, respectively) and lower AST concentrations at 24 h po (p = 0.043, respectively) than the others. Conclusions: The expression of ERα- and ERβ-mRNA is present in the myocardium of children and young adults with congenital cardiac defect and is associated with lower markers of po organ damage. This suggests that ERs may provide perioperative organ protection in this population.

Effect of modified ultrafiltration on cytokines and hemoconcentration in dogs undergoing cardiopulmonary bypass

Cardiac surgery using cardiopulmonary bypass (CPB) generates severe inflammatory reactions secondary to hemodilution and surgical stress. This study was conducted to evaluate whether modified ultrafiltration (MUF) could be performed safely and to clarify its effects during mitral valve repair in dogs in terms of hemodilution and the status of inflammatory cytokines. We retrospectively studied 38 dogs with mitral valve disease who underwent MUF immediately after mitral valve repair under CPB. To determine the effect of MUF, we measured the pre- and post-MUF blood dilution and blood cytokine levels. The levels of red blood cells, hematocrit (HCT), and albumin were significantly increased after MUF, whereas interleukin (IL)-6 levels were significantly increased from 24.3 (range 9.6–54.6) to 32.3 (15.9–65.1) pg/ml. The levels of IL-8 and IL-10 declined significantly after MUF, from 368.2 (246.1–669.4) and 45.4 (28.6–76.1) to 272.2 (174.1–414.4) and 28.8 (18.8–44.5) pg/ml, respectively. Our results demonstrated that MUF can be applied in dogs undergoing CPB and is effective in achieving hemoconcentration. Moreover, MUF may be useful for the removal of cytokines. Further studies are needed to validate these findings and clarify the effects of inflammatory cytokines after CPB.

Meeting nutritional needs of infants under 3 months of life within the first week after cardiovascular surgery

BACKGROUND

After heart surgery requiring cardiopulmonary bypass, neonates have a profound metabolic response to stress. If adequate nutritional support is not provided this leads to loss of lean mass and deterioration of vital organs. The objective of this study was to describe the nutritional status and nutritional support achieved in infants younger than 3 months of life undergo in cardiovascular surgery.

METHODS

A prospective, descriptive study was conducted in a Pediatric Cardiovascular intensive therapy at tertiary care center. All patients younger than 3 months of life admitted to the cardiovascular unit undergoing heart surgery between April 2013 and May2014 were included. We proposed to achieve 67 kcal/kg/day as one of the nutritional intervention goals. The children were evaluated on admission and at 3 and 7 days post-surgery.

RESULTS

Seventy-four patients were evaluated. Total parenteral nutrition could be implemented in all patients that were entered into the protocol requiring parenteral nutrition. Mean volume administered over this period was 50 mL/kg/day (range, 25 to 80 mL/kg/day). Evaluation on admission, at 72 hours, and one week postoperatively showed that 70%, 69%, and 62.7% of the patients, respectively, were not able to achieve the 67 kcal/kg/day proposed as one of the nutritional intervention goals. It was found that at the three study time points enteral and parental caloric intake could cover 100% of the metabolic resting energy expenditure (REE) estimated using the Schofield and WHO equations with no significant differences between the two.

CONCLUSIONS

Although the calorie intake proposed by our intervention was not achieved, it did cover 100% of the REE calculated by the equations.

Albumin 5% Versus Crystalloids for Fluid Resuscitation in Children After Cardiac Surgery

OBJECTIVES

To determine the clinical benefit of using colloids versus crystalloids for volume resuscitation in children admitted after cardiac surgery.

DESIGN

Retrospective pre-/postintervention cohort study.

SETTING

Stollery Children's Hospital tertiary care pediatric cardiac ICU.

PATIENTS

Children admitted to the pediatric cardiac ICU after cardiac surgery.

INTERVENTIONS

Fluid resuscitation policy change in which crystalloids replaced albumin 5% as the primary fluid strategy for resuscitation after cardiac surgery.

MEASUREMENTS AND MAIN RESULTS

Children who underwent cardiac surgery in the 6 months prior to the policy change (5% albumin group) were compared with children admitted during the 6 months after (crystalloid group). Demographic, perioperative, and outcome variables (fluid intake days 1-4 postoperative, vasoactive therapy, blood products, time to negative fluid balance, renal replacement therapies, mechanical ventilation, pediatric cardiac ICU, and length of stay) were collected. Data were analyzed using linear and logistic multivariate analysis. The study included 360 children. There was no association between fluid group and fluid intake (mL/kg) on day 1 postoperatively (coefficient, 2.84; 95% CI, 5.37-11.05; p = 0.497). However, crystalloid group was associated with significantly less fluid intake on day 2 (coefficient, -12.8; 95% CI, -22.0 to -3.65; p = 0.006), day 3 (coefficient, -14.9; 95% CI, -24.3 to -5.57; p = 0.002), and on the first 48 hours postoperative (coefficient, 10.1; 95% CI, -27.9 to -1.29; p = 0.032). Pediatric cardiac ICU stay (coefficient, -1.29; 95% CI, -2.50 to -0.08; p = 0.036) was shorter for the crystalloid group. There were no significant differences in the time to negative balance, need for renal replacement therapy, mechanical ventilation days, hospital stay, or pediatric cardiac ICU survival.

CONCLUSIONS

In our study, the use of albumin 5% for resuscitation after cardiac surgery was not associated with less fluid intake but rather the opposite. Albumin administration did not provide measured clinical benefit while exposing children to side effects and generating higher costs to the healthcare system.

Arrhythmias in Children in Early Postoperative Period After Cardiac Surgery

Background:

Postoperative arrhythmias are a known complication after cardiac surgical repairs for congenital heart disease.

Methods:

Data were reviewed pertaining to incidence, diagnosis, potential risk factors, and management of postoperative arrhythmias in 369 consecutive patients under 18 years of age, undergoing elective open heart surgery. All children were admitted to the intensive care unit and continuous electrocardiographic monitoring was performed. Patient factors such as Aristotle Basic Complexity Score, total surgical duration, hypotension, tachycardia, serum lactate level, and inotropic score were analyzed. Univariate analysis was done to assess associations between these factors and the occurrence of postoperative arrhythmias.

Results:

Twenty-five (6.7%) patients developed arrhythmias. Junctional ectopic tachycardia (JET) was the most common arrhythmia occurring in 15 (60%) patients, followed by supraventricular tachycardia in 3 (12%), ventricular premature contractions in 3 (12%), hemodynamically unstable ventricular tachycardia and fibrillation in 3 (12%), and atrial fibrillation in 1 (4%) patient. Different grades of heart block were noted in 13 patients. Aristotle score (P = .014), total surgical duration (P < .01), hypotension (P = .02), heart rate (beats per minute) (P = .001), serum lactate level (P = .04), and inotropic score (P = .02) in the early postoperative period were associated with arrhythmia occurrence. Surgeries for ventricular septal defect alone or in association with other diseases including tetralogy of Fallot (TOF) and transposition of the great arteries (TGA) were found to be associated with higher risk of arrhythmias.

Conclusion:

This study showed a low incidence of arrhythmias, JET being the commonest, seen more in TOF repair and these could be treated efficiently. Higher Aristotle score, longer surgical time, hypotension, tachycardia, high inotropic score, and high serum lactate levels were associated with the occurrence of arrhythmias postoperatively.

A Case-Control Analysis of Postoperative Fluid Balance and Mortality After Pediatric Cardiac Surgery

OBJECTIVES

A positive fluid balance after cardiac surgery may be associated with poor outcomes; however, previous studies looking at this association have been limited by the number of deaths in the study population. Our primary aim was to determine the relationship between postoperative cumulative fluid balance and mortality in cardiac surgical patients. Secondary aims were to study the association between fluid balance and duration of mechanical ventilation, intensive care and hospital length of stay.

DESIGN

Case-control study.

SETTING

A 30-bed multidisciplinary PICU.

PATIENTS

All patients admitted to the PICU following cardiac surgery from 2010 to 2014.

INTERVENTIONS

Deaths during PICU admission following cardiac surgery (cases) were matched 1:3 with children who survived to PICU discharge (controls) using the following criteria: age at surgery (within a 20% age range), Risk Adjusted Congenital Heart Surgery (RACHS-1) category, and year of admission.

MEASUREMENTS AND MAIN RESULTS

Of 1,996 eligible children, 46 died (2.3%) of whom 45 (98%) were successfully matched. Cumulative fluid balance on days 2 and 7 was not associated with PICU mortality. On multivariable analysis, factors associated with mortality were cardiopulmonary bypass time (per 10-min increase, odds ratio [95% CI], 1.06 [1.00-1.12]; p = 0.03), extracorporeal membrane oxygenation requirement within 3 days (46.6 [9.47-230.11]; p < 0.001), peak serum chloride (mmol/L) in the first 48 hours (1.12 [1.01-1.23]), and time to start peritoneal dialysis after surgery (in comparison to no peritoneal dialysis, odds ratio [95% CI] in those started on early peritoneal dialysis was 1.07 [0.33-3.41]; p = 0.90 and in late peritoneal dialysis 3.65 [1.21-10.99]; p = 0.02). Children with cumulative fluid balance greater than or equal to 5% by day 2 spent longer on mechanical ventilation (median [interquartile range], 211 hr [97-539] vs 93 hr [34-225]; p <0.001), in PICU (11 d [8-26] vs 6 [3-13]; p < 0.001) and in hospital (22 d [13-39] vs 14 d [8-30]; p = 0.001).

CONCLUSIONS

Early fluid overload is not associated with mortality. However, it is associated with increased duration of mechanical ventilation and PICU length of stay. Early peritoneal dialysis commencement (compared with late peritoneal dialysis) after surgery was associated with decreased mortality.

Management of children with congenital heart defect: state of the art and future prospects

The treatment of children with congenital heart defects has evolved in the last 60 years from conservative care to a highly specialized management where advances in imaging, surgical, interventional and support techniques meet together to ensure satisfactory development and good quality of life to the child and to the upcoming grown up. Management of congenital heart defects best begins before birth with the aim, whenever possible, to maintain or establish biventricular physiology or, if this is excluded, to optimize the conditions for univentricular physiology. Current research in the field of genetics, device bioengineering and miniaturization, stem cell therapy, and fusion imaging technology is expected to help to improve further patient outcome. In this review, current management strategies and future prospects are discussed.

Mannose-binding lectin (MBL) insufficiency protects against the development of systemic inflammatory response after pediatric cardiac surgery

We investigated MBL2 and MASP2 genotypes, serum MBL (mannose-binding lectin) levels and activities of its complexes with associated serine proteases (MASP-1, MASP -2), in relation to complications following cardiac surgery in 195 children. The incidence of SIRS was lower in patients carrying MBL2 A/O and O/O genotypes (p=0.024). Children with MBL levels <500ng/ml had a lower risk of SIRS (p=0.014) and fever (p=0.044). Median MBL concentration was higher in patients who developed SIRS (p=0.048) but lower in those with post-operative infections (p=0.046). MBL-MASP-2 activities <100mU/ml protected from SIRS (p=0.007), low cardiac output syndrome (p=0.03) and multiorgan failure (p=0.012). In contrast, MBL2 YA/YA genotypes were associated with SIRS (p=0.018), low cardiac output syndrome (p=0.018), fever (p=0.018) and high inotropic score (VIS>30) (p=0.021). Thus, low MBL concentrations and associated genotypes may protect patients from systemic inflammation while high MBL serum levels and corresponding genotypes are risk factors of postoperative complications.

Early postoperative arrhythmias after pediatric cardiac surgery

BACKGROUND

This prospective study proposed to determine the incidence, risk factors, and management protocols for early postoperative arrhythmias after pediatric cardiac surgery, with focus on outcomes, using a uniform protocol, and also to see if children operated on at a later age have different issues from those operated on earlier.

METHODS

Of 224 consecutive pediatric patients undergoing cardiac surgery from September 2013 to July 2014, 24 were excluded because their procedures were performed without cardiopulmonary bypass.

RESULTS

The median age was 24 months (mean 50.1 ± 62.4 months, range 0.5-216 months). Fifteen (7.5%) patients developed arrhythmia, the most common was junctional ectopic tachycardia (n = 7, 46.6%) followed by supraventricular tachycardia (n = 5, 33.3%). All junctional ectopic tachycardias occurred within 24 h of intensive care unit admission. Of the 7 patients with junctional ectopic tachycardia, 5 responded to conventional measures and 2 required amiodarone infusion. There was a significant longer cardiopulmonary bypass time in patients with arrhythmias compared to those without arrhythmias.

CONCLUSION

We observed a very low incidence of arrhythmias, particularly junctional ectopic tachycardia, after open heart surgery in children. Other than a longer cardiopulmonary bypass time, no specific predictors were identified. It appears that the cause of arrhythmias following pediatric cardiac surgery is multifactorial and needs further study with a greater number of patients.

Safety and utility of passive peritoneal drainage following Fontan palliation

OBJECTIVE

Placement of peritoneal drainage catheters intra-operatively has been shown to help prevent fluid overload in children recovering from surgery for two-ventricle heart disease. We aimed to determine whether this practice is also helpful in children recovering from Fontan palliation.

MATERIAL AND METHODS

A retrospective review was performed on children with single-ventricle anatomy undergoing Fontan palliation at our institution from 2007 to 2011. Variables in those with peritoneal drainage were compared with those without using t-tests, Mann-Whitney U-tests, chi-square tests, or analysis of variance for repeated measures as appropriate. Data were represented as mean with standard deviation unless otherwise noted.

RESULTS

A total of 43 children were reviewed, 21 (49%) with peritoneal drainage catheters. No complications from catheter placement occurred. The groups did not differ with regard to cardiopulmonary bypass duration, dominant ventricle, pre-operative haemodynamic data, fenestration use, and initial intensive care unit ventilation index. Central venous pressures, vasoactive medication use, and diuretic use during the first 48 hours were also not statistically different. At 48 hours, the median fluid balance was -9 (interquartile range : -50, +20) in those with peritoneal drainage and +77 cc/kg (interquartile range : +22, +96) in those without (p < 0.001), yet median duration of mechanical ventilation was 40 hours (range: 19-326) in those with peritoneal drainage and 23 hours (range: 9-92) in those without, p = 0.01.

CONCLUSION

Patients with peritoneal drainage recovering from Fontan palliation achieved negative fluid balance as compared with those without peritoneal drainage, although this difference was associated with a longer duration of mechanical ventilation.

Major cardiac surgery induces an increase in sex steroids in prepubertal children

While the neuroprotective benefits of estrogen and progesterone in critical illness are well established, the data regarding the effects of androgens are conflicting. Surgical repair of congenital heart disease is associated with significant morbidity and mortality, but there are scant data regarding the postoperative metabolism of sex steroids in this setting. The objective of this prospective observational study was to compare the postoperative sex steroid patterns in pediatric patients undergoing major cardiac surgery (MCS) versus those undergoing less intensive non-cardiac surgery. Urinary excretion rates of estrogen, progesterone, and androgen metabolites (μg/mmol creatinine/m(2) body surface area) were determined in 24-h urine samples before and after surgery using gas chromatography-mass spectrometry in 29 children undergoing scheduled MCS and in 17 control children undergoing conventional non-cardiac surgery. Eight of the MCS patients had Down's syndrome. There were no significant differences in age, weight, or sex between the groups. Seven patients from the MCS group showed multi-organ dysfunction after surgery. Before surgery, the median concentrations of 17β-estradiol, pregnanediol, 5α-dihydrotestosterone (DHT), and dehydroepiandrosterone (DHEA) were (control/MCS) 0.1/0.1 (NS), 12.4/11.3 (NS), 4.7/4.4 (NS), and 2.9/1.1 (p=0.02). Postoperatively, the median delta 17β-estradiol, delta pregnanediol, delta DHT, and delta DHEA were (control/MCS) 0.2/6.4 (p=0.0002), -3.2/23.4 (p=0.013), -0.6/3.7 (p=0.0004), and 0.5/4.2 (p=0.004). Postoperative changes did not differ according to sex. We conclude that MCS, but not less intensive non-cardiac surgery, induced a distinct postoperative increase in sex steroid levels. These findings suggest that sex steroids have a role in postoperative metabolism following MCS in prepubertal children.

Prevalence of and risk factors for early postoperative arrhythmia in children after cardiac surgery

BACKGROUND

The aims of this study were to (i) evaluate postoperative arrhythmias following congenital heart surgery, on 12-lead electrocardiography and Holter monitoring; and (ii) analyze the association between the type of repair and postoperative arrhythmia.

METHODS

A total of 229 children and 10 neonates with a mean age of 4.71 ± 0.41 years (range, 15 days-17 years) who underwent congenital cardiac surgery were included the study. Twelve-lead electrocardiography and Holter monitoring were used to evaluate arrhythmias after the operation.

RESULTS

Within the evaluation period, 104 patients (43.5%) developed arrhythmias after surgery. No arrhythmias were observed in neonates. Female sex (51.9%) was slightly associated with the occurrence of arrhythmias after operation. The most common arrhythmia was supraventricular extra-systoles (65.4%). Risk factors for supraventricular extra-systoles were repair of secundum atrial septal defect (32.3%), ventricular septal defect (25%) and tetralogy of Fallot (14.7%). Also, ventricular extra-systoles were associated with repair of ventricular septal defect.

CONCLUSIONS

Postoperative arrhythmia is usually a frequent and transient phenomenon after congenital cardiac surgery, and is provoked by both mechanical irritation of the conduction system and humoral factors. Postoperative arrhythmia should be anticipated in patients with congenital cardiac surgery. Finally, the association between this type of surgical repair and arrhythmia may be helpful for estimating the type of arrhythmia that develops after congenital cardiac surgery in children.

The effects of multiple doses of glucocorticoids on the inflammatory response to cardiopulmonary bypass in children

BACKGROUND

We previously demonstrated that a dose of glucocorticoids (GCs) administered prior to cardiopulmonary bypass (CPB) is effective at suppressing the inflammatory response to CPB and leads to an improved postoperative course. We evaluated whether an additional dose of GC administered eight hours prior to CPB would lead to further clinical benefit.

METHODS

We conducted a prospective study in which patients were randomized to receive placebo or GC eight hours prior to CPB, in addition to a dose of GC administered following induction of anesthesia. We measured serum inflammatory mediator levels and postoperative clinical parameters.

RESULTS

Thirty-one patients were included in the study. Eighteen patients received two doses of GC and 13 patients received a single does of GC. Complement C3a levels were significantly lower at 24 hours following surgery in those patients who received two doses of GC (3136 ± 1650 vs 1779 ± 1616 ng/mL, P = .04). There was no significant difference in tumor necrosis factor (TNF)-α or interleukin (IL)-6 levels at any time between groups. There was no significant difference in core body temperature or renal function (based on serum creatinine levels) between groups. There was no significant difference between groups in duration of mechanical ventilation (2.4 ± 1.5 vs 3.6 ± 3.7 days, two vs one dose, respectively, P = .33) or length of stay in the intensive care unit ([ICU]; 3.4 ± 1.4 vs 4.9 ± 3.6 days, 2 vs 1 dose, respectively, P = .15).

CONCLUSION

While those patients who received two doses of GC prior to surgery had significantly less complement activation postoperatively, clinical outcomes did not differ between groups. We conclude that the practice of administering an additional dose of GC prior to CPB is not supported. However, a large randomized study is needed to conclusively discount the potential benefit of this strategy.

Adrenomedullin alterations related to cardiopulmonary bypass in infants with low cardiac output syndrome

BACKGROUND

Low cardiac output syndrome (LCOS) remains a major perioperative complications in infants subjected to open-heart surgery with cardiopulmonary bypass (CPB). The present study investigated whether perioperative blood assessment of a potent vasoactive peptide namely adrenomedullin (AM) can predict the risk of LCOS.

METHODS

We measured AM levels in 48 patients (LCOS: n = 9; controls: n = 39) undergone to open-heart surgery with CPB at five predetermined time points before, during and after the surgery. Clinical, laboratory and perioperative data were analyzed by a multiple logistic regression model.

RESULTS

AM significantly decreased (p < 0.01) during and after the surgical procedure exhibiting a dip at the end of the CPB. Multivariable analysis demonstrated significant correlations among LCOS, AM measured at the end of CPB (p < 0.001), and cooling duration (p < 0.05). AM at 27 pg/L cutoff achieved a sensitivity of 100% and a specificity of 64.1%, while cooling at 11-min cutoff combined a sensitivity of 55.6% and a specificity of 92.3% for LCOS prediction.

CONCLUSIONS

This study suggests that AM can constitute, alone or combined with standard parameters, a promising predictor of LCOS in infants subjected to open-heart surgery with CPB.

Cardiopulmonary bypass and serum thyroid hormone profile in pediatric patients with congenital heart disease

OBJECTIVE

To study the effect of cardiopulmonary bypass (CPB) on serum thyroid hormone profile in children undergoing open-heart surgery.

DESIGN

Prospective cross-sectional study.

SETTING

Multispecialty tertiary level referral center.

PATIENTS

One hundred consecutive patients (age 15.9 ± 14.6 months, weight 6.7 ± 2.5 kg) undergoing open-heart surgery under CPB.

INTERVENTIONS

None.

OUTCOME MEASURES

Levels and trends of serum total thyroxine (TT4), free thyroxine (FT4), total tri-iodothyronine (TT3), free tri-iodothyronine (FT3) and thyroid stimulating hormone (TSH), survival, inotropic score, duration of mechanical ventilation, postoperative complications.

RESULTS

TT4 levels were 9.08 ± 3.6, 6.4 ± 2.5, 6.24 ± 2.1, 6.43 ± 2.4, 7.20 ± 3.0 µg/dL at baseline and at 1, 24, 48 and 72 hours; FT4 levels were 1.82 ± 0.5, 1.49 ± 0.3, 1.29 ± 0.3, 1.32 ± 0.4, and 1.43 ± 0.5 ng/dL; TT3 levels were 1.81 ± 0.4, 1.31 ± 0.3, 0.99 ± 0.2, 1.0 ± 0.37, and 1.17 ± 0.48 ng/ml; FT3 levels were 4.09 ± 1.0, 3.02 ± 0.8, 2.21 ± 0.6, 2.22 ± 0.7, and 2.66 ± 1.05 pg/ml; TSH levels were 5.40 ± 3.8, 2.0 ± 3.1, 1.24 ± 1.1, 2.90 ± 3.3, and 4.03 ± 3.4 mIU/L. There was significant fall (29.1% for FT4, 32.1% for TT4, 77% for TSH, 46% for FT3 and 45% for TT3, p < 0.0001). When area under curve (AUC) TT4 was compared between survivors (n = 87) and nonsurvivors (n = 12), significantly larger AUC was seen in survivors (492.81 ± 158.6) than nonsurvivors (360.75 ± 179.6 p = 0.0125). In survivors >72 hours, AUC TT4 was larger in patients with uneventful postoperative course versus those with postoperative complications (516.48 ± 18.6 vs. 394.78 ± 29.9, p = 0.001). AUC TT4 showed significant inverse correlation with inotropic score and borderline inverse correlation with duration of mechanical ventilation.

CONCLUSION

Children undergoing surgery under CPB showed significant fall in thyroid hormones. Because TT4 level is modifiable, prophylactic administration of TT4 for improving outcomes needs to be studied further.

Dexamethasone pretreatment provides antiinflammatory and myocardial protection in neonatal arterial switch operation

BACKGROUND

This prospective double-blinded randomized study tested the hypothesis that preoperative treatment with dexamethasone would attenuate inflammatory priming of the myocardium, reduce the systemic inflammatory reaction upon cardiac operation, and provide organ protection in neonates.

METHODS

Twenty neonates (age, 8 to 21 days) with transposition of the great arteries scheduled for arterial switch operation were included. Nine received dexamethasone (1 mg/kg body weight) 4 hours before cardiopulmonary bypass, and 11 received natrium chloride. We studied intramyocardial messenger RNA expression of interleukin (IL)-6, IL-8, IL-1β, and tumor necrosis factor-α (TNF-α), as well as IL-10 and expression of TNF-α on protein level in right atrial tissue taken before institution of CPB. We measured plasma levels of IL-6, IL-10, lipopolysaccharide binding protein, and cardiac troponin T. Cytokine expression was related to postoperative outcome.

RESULTS

Pretreatment with dexamethasone led to a significant decrease in myocardial expression of IL-6, IL-8, IL-1β, and TNF-α messenger RNA and to a decrease in protein synthesis of TNF-α. Plasma concentrations of IL-6 were significantly lower and those of IL-10 significantly higher in pretreated patients. This was associated with lower cardiac troponin T values and lower dobutamine requirement. Levels of lipopolysaccharide binding protein were significantly higher postoperatively in pretreated neonates.

CONCLUSIONS

Dexamethasone administration before arterial switch operation leads to a shift in the myocardial and systemic cytokine expression profile in neonates with transposition of the great arteries, with downregulation of proinflammatory and upregulation of antiinflammatory cytokines. Lower myocardial cell damage and lower catecholamine requirement suggest myocardial protection in treated patients.

Passive peritoneal drainage improves fluid balance after surgery for congenital heart disease

OBJECTIVE

In some centers, passive peritoneal drainage (PD) is implemented following surgery for congenital heart disease. The utility of this practice has yet to be studied. We hypothesized that passive PD can promote negative fluid balance without compromising intravascular volume.

METHODS

A retrospective review of infants who underwent repair of complete atrioventricular septal defect (AVSD) between 6/2006 and 8/2010 was completed. Data are represented as mean ± standard deviation.

RESULTS

Thirty-six infants underwent AVSD repair, 18 of whom had PD catheters placed without complication. Infants with passive PD had longer duration of cardiopulmonary bypass (211 ± 59 vs 137 ± 41 min, P < 0.001) and aortic cross-clamp (148 ± 29 vs 102 ± 21 min, P < 0.001); had higher Aristotle complexity score (12.6 ± 3 vs 10.7 ± 2, P = 0.03) and ventilatory support immediately after surgery (ventilation index score 19.5 ± 6.5 vs 14.3 ± 2.5, P = 0.004); and received greater fluid administration (225 ± 6 3 vs 168 ± 45 ml kg(-1), P = 0.002) in the first 48 postoperative hours. Despite these differences, infants with passive PD achieved negative fluid balance more rapidly (12 ± 10 vs 27.3 ± 13 h, P < 0.0001) and to a greater extent (-73 + 55 vs +2.6 + 39 mL kg(-1) at 48 h, P = 0.002). Moreover, postoperative hemodynamics, urine output, creatinine clearance, blood urea nitrogen, peak lactate, and duration of mechanical ventilation were similar between groups.

CONCLUSIONS

Passive PD is safe and promotes negative fluid balance after repair of complete AVSD without adversely affecting intravascular volume.

Management of the postoperative pediatric cardiac surgical patient

OBJECTIVE

To review the salient aspects and latest advances in the management of the postoperative pediatric cardiac patient.

DATA SOURCE

A Medline-based literature source.

CONCLUSION

The practice of pediatric cardiac intensive care has evolved considerably over the last several years. These efforts are the result of a collaborative effort from all subspecialties involved in the care of pediatric patients with congenital heart disease. Discoveries and innovations that are representative of this effort include the extension of cerebral oximetry from the operating room into the critical care setting; mechanical circulatory devices designed for pediatric patients; and surgery in very low birth weight neonates. Advances such as these impact postoperative management and make the field of pediatric cardiac intensive care an exciting, demanding, and evolving discipline, necessitating the ongoing commitment of various disciplines to pursue a greater understanding of disease processes and how to best go about treating them.

Risk, clinical features, and outcomes of thrombosis associated with pediatric cardiac surgery

BACKGROUND

Thrombosis, usually considered a serious but rare complication of pediatric cardiac surgery, has not been a major clinical and/or research focus in the past.

METHODS AND RESULTS

We noted 444 thrombi (66% occlusive, 60% symptomatic) in 171 of 1542 surgeries (11%). Factors associated with increased odds of thrombosis were age <31 days (odds ratio [OR], 2.0; P=0.002), baseline oxygen saturation <85% (OR, 2.0; P=0.001), previous thrombosis (OR, 2.6; P=0.001), heart transplantation (OR, 4.1; P<0.001), use of deep hypothermic circulatory arrest (OR, 1.9 P=0.01), longer cumulative time with central lines (OR, 1.2 per 5-day equivalent; P<0.001), and postoperative use of extracorporeal support (OR, 5.2; P<0.001). Serious complications of thrombosis occurred with 64 of 444 thrombi (14%) in 47 of 171 patients (28%), and were associated with thrombus location (intrathoracic, 45%; extrathoracic arterial, 19%; extrathoracic venous, 8%; P<0.001), symptomatic thrombi (OR, 8.0; P=0.02), and partially/fully occluding thrombi (OR, 14.3; P=0.001); indwelling access line in vessel (versus no access line) was associated with lower risk of serious complications (OR, 0.4; P=0.05). Thrombosis was associated with longer intensive care unit (+10.0 days; P<0.001) and hospital stay (+15.2 days; P<0.001); higher odds of cardiac arrest (OR, 4.9; P<0.001), catheter reintervention (OR, 3.3; P=0.002), and reoperation (OR, 2.5; P=0.003); and increased mortality (OR, 5.1; P<0.001). Long-term outcome assessment was possible for 316 thrombi in 129 patients. Of those, 197 (62%) had resolved at the last follow-up. Factors associated with increased odds of thrombus resolution were location (intrathoracic, 75%; extrathoracic arterial, 89%; extrathoracic venous, 60%; P<0.001), nonocclusive thrombi (OR, 2.2; P=0.01), older age at surgery (OR, 1.2 per year; P=0.04), higher white blood cell count (OR, 1.1/10(9) cells per 1 mL; P=0.002), and lower fibrinogen (OR, 1.4/g/L; P=0.02) after surgery.

CONCLUSIONS

Thrombosis affects a high proportion of children undergoing cardiac surgery and is associated with suboptimal outcomes. Increased awareness and effective prevention and detection strategies are needed.

Immune dysregulation after cardiothoracic surgery and incidental thymectomy: maintenance of regulatory T cells despite impaired thymopoiesis

Thymectomy is performed in infants during cardiothoracic surgery leaving many patients with reduced thympopoiesis. An association between immune disorders and regulatory T cells (Treg) after incidental thymectomy has not been investigated. Questionnaires soliciting symptoms of atopic or autoimmune disease and biomarkers were measured in children and adults with congenital heart disease and either reduced or preserved thymopoiesis. Tregs were examined. Atopic or autoimmune-like symptoms and elevated anti-dsDNA antibodies were common after surgery in individuals with low thymopoiesis. Total Treg number and function were maintained but with fewer naïve Treg. TCR spectratypes were similar to other memory T cells. These data suggest that thymectomy does not reduce total Treg number but homeostasis is affected with reduced naïve Treg. Prevalence of autoimmune or atopic symptoms after surgery is not associated with total number or proportion of Tregs but appears to be due to otherwise unknown factors that may include altered Treg homeostasis.

Prevalence of and risk factors for perioperative arrhythmias in neonates and children after cardiopulmonary bypass: continuous holter monitoring before and for three days after surgery

Background

A comprehensive evaluation of postoperative arrhythmias following surgery for congenital heart disease by continuous Holter monitoring has not been carried out. We aimed, firstly, to establish the time course of pre- and early postoperative arrhythmias by beat-to-beat analysis following cardiopulmonary bypass and, secondly, to examine which surgical procedures present risk factors for specific arrhythmias.

Methods

494 consecutive patients, including 96 neonates, were studied with serial 24-hour Holter electrocardiograms before as well as uninterruptedly during the first 72 hours after surgery and prior to discharge.

Results

Within 24 hours of surgery 59% of the neonates and 79% of the older children developed arrhythmias. Junctional ectopic tachycardia occurred in 9% of neonates and 5% of non-neonates and ventricular tachycardia in 3% and 15%, respectively.

For neonates, male sex and longer cross-clamping time independently increased the risk for arrhythmias (odds ratios 2.83 and 1.96/minute, respectively). Ventricular septal defect repair was a strong risk factor for junctional ectopic tachycardia in neonates and in older children (odds ratios 18.8 and 3.69, respectively). For infants and children, older age (odds ratio 1.01/month) and closure of atrial septal defects (odds ratio 2.68) predisposed to arrhythmias of any type.

Conclusions

We present the largest cohort of neonates, infants and children that has been prospectively studied for the occurrence of arrhythmias after cardiac surgery. Postoperative arrhythmias are a frequent and transient phenomenon after cardiopulmonary bypass, provoked both by mechanical irritation of the conduction system and by humoral factors.

Bicarbonate-buffered ultrafiltration during pediatric cardiac surgery prevents electrolyte and acid-base balance disturbances

Pediatric cardiopulmonary bypass is still a challenge because of electrolyte disturbances and inflammation. Many investigations deal with different types of hemofiltration to reduce these potentially harmful side effects. We tested the hypothesis of whether bicarbonate-buffered hemofiltration of the priming solution minimizes electrolyte and acid-base disturbances during the initiation of cardiopulmonary bypass and whether bicarbonate-buffered hemofiltration performed during cardiopulmonary bypass could reduce cytokine levels. Twenty children younger than 2 years of age (mean age 166 ± 191 days; mean weight 6.42 ± 3.22 kg) scheduled for pediatric cardiac surgery with cardiopulmonary bypass were enrolled in this prospective clinical study. Cardiopulmonary bypass circuits were primed with a bicarbonate-buffered hemofiltration solution, gelatin and 1 unit of packed red blood cells. The priming was hemofiltered using an ultrahemofilter until approximately 1000 mL of ultrafiltrate was restored with the buffered solution. Further hemofiltration was performed throughout the whole bypass time, especially during rewarming. Blood gas analyses and inflammatory mediators were monitored during the operation. Blood gas analysis results after initiation of cardiopulmonary bypass and throughout the entire study remained within the physiologic ranges. Even potassium decreased from 4.0 ± 0.3 to 3.4 ± 0.4 mmol.l−1 after initiation of cardiopulmonary bypass. Plasma levels of tumor necrosis factor alpha decreased significantly (47 ± 44 vs. 24 ± 21 pg.mL−1) whereas complement factor C3a (5.0 ± 2.9 vs. 16.8 ± 6.6 ng.mL−1) and interleukin-6 (7.3 ± 15.2 vs. 110 ± 173 pg.mL−1) increased despite hemofiltration. In conclusion, this study shows that bicarbonate-buffered ultrafiltration is an efficient, simple and safe method for performing hemofiltration, both of the priming solution and during the entire bypass time. The use of a physiological restitution solution prevents electrolyte and acid-base balance disturbances. The elimination of inflammatory mediators seems to be as effective as other ultrafiltration methods.

A neutrophil elastase inhibitor, sivelestat, improved respiratory and cardiac function in pediatric cardiovascular surgery with cardiopulmonary bypass

PURPOSE

Several reports indicate that a neutrophil elastase inhibitor, sivelestat, may have prophylactic efficacy against a systemic inflammatory response after cardiovascular surgery with cardiopulmonary bypass (CPB). We evaluated the clinical pulmonary and cardiac effects of sivelestat.

METHODS

We performed a retrospective study of 25 pediatric patients who underwent elective cardiovascular surgery with CPB for ventricular septal defect with pulmonary hypertension. Ten patients received 0.2 mg x kg(-1) x h(-1) sivelestat; the other is patients were the control group. There were no significant differences in demographic characteristics between the two groups. The P(a)O(2)/fractional inspired oxygen (F(I)O(2); P/F) ratio, the respiratory index (RI), and the fractional area change (FAC) of the left ventricle (LV) in the postoperative course were measured.

RESULTS

The P/F ratio was higher in the sivelestat group compared with the control group and there were significant differences between the two groups immediately after weaning form CPB, and at 12 h after weaning from CPB (P < 0.05). The RI was lower in the sivelestat group compared with the control group and there were significant differences between the two groups at immediately after weaning from CPB, and at 6 h and 12 h after CPB (P < 0.05). The FAC of the LV was significantly better in the sivelestat group and there was a significant difference between the two groups on postoperative day (POD) 3 (P < 0.05).

CONCLUSION

We have shown that pediatric patients who underwent cardiovascular surgery with CPB who received sivelestat had a higher P/F ratio, a lower RI, and better FAC of the LV in the postoperative course.

Risk stratification in neonates and infants submitted to cardiac surgery with cardiopulmonary bypass: a multimarker approach combining inflammatory mediators, N-terminal pro-B-type natriuretic peptide and troponin I

Low cardiac output syndrome (LCOS) is a common problem following cardiac surgery with cardiopulmonary bypass (CPB) in neonates and infants, and its early recognition remains a challenging task. We aimed to test whether a multimarker approach combining inflammatory and cardiac markers provides complementary information for prediction of LCOS and death in children submitted to cardiac surgery with CPB. Forty-six children younger than 18 months with congenital heart defects were prospectively enrolled. No intervention was made. Blood samples were collected pre-operatively, during CPB and post-operatively (PO) for measurement of interleukin (IL)-6, IL-8, IL-10, tumor necrosis factor (TNF)-alpha, cardiac troponin I (cTnI) and N-terminal pro-B-type natriuretic peptide (NT-proBNP). Clinical data and outcome variables were recorded. Logistic regression was used to identify predictors of LCOS and death. Multivariate logistic regression identified pre-operative NT-proBNP and IL-8 4h PO as independent predictors of LCOS, while cTnI 4h PO and CPB length were independent predictors of death. The use of inflammatory and cardiac markers in combination improved sensitivity, negative predictive value and accuracy of the models. In conclusion, the combined assessment of inflammatory and cardiac biochemical markers can be useful for identifying young children at increased risk for LCOS and death after heart surgery with CPB.

Characterizing the Inflammatory Response to Cardiopulmonary Bypass in Children

Cardiopulmonary bypass is known to trigger a global inflammatory response. Age-dependent differences in the inflammatory response, the increased susceptibility to injury of immature organ systems, and the larger extracorporeal circuit to patient size ratio results in greater susceptibility of younger and smaller patients to the damaging effects of cardiopulmonary bypass. In this review the components of the inflammatory response to cardiopulmonary bypass are reviewed with special reference to the pediatric age group, including the age-specific impact on organ systems. In addition the current and evolving strategies to prevent, limit, and treat the inflammatory response to cardiopulmonary bypass in children are examined.

Clinical review: thyroid hormone replacement in children after cardiac surgery--is it worth a try?

Cardiac surgery using cardiopulmonary bypass produces a generalized systemic inflammatory response, resulting in increased postoperative morbidity and mortality. Under these circumstances, a typical pattern of thyroid abnormalities is seen in the absence of primary disease, defined as sick euthyroid syndrome (SES). The presence of postoperative SES mainly in small children and neonates exposed to long bypass times and the pharmacological profile of thyroid hormones and their effects on the cardiovascular physiology make supplementation therapy an attractive treatment option to improve postoperative morbidity and mortality. Many studies have been performed with conflicting results. In this article, we review the important literature on the development of SES in paediatric postoperative cardiac patients, analyse the existing information on thyroid hormone replacement therapy in this patient group and try to summarize the findings for a recommendation.

Modulation of systemic inflammatory response after cardiac surgery

Cardiac surgery and cardiopulmonary bypass initiate a systemic inflammatory response largely determined by blood contact with foreign surfaces and the activation of complement. It is generally accepted that cardiopulmonary bypass initiates a whole-body inflammatory reaction. The magnitude of this inflammatory reaction varies, but the persistence of any degree of inflammation may be considered potentially harmful to the cardiac patient. The development of strategies to control the inflammatory response following cardiac surgery is currently the focus of considerable research efforts. Diverse techniques including maintenance of hemodynamic stability, minimization of exposure to cardiopulmonary bypass circuitry, and pharmacologic and immunomodulatory agents have been examined in clinical studies. This article briefly reviews the current concepts of the systemic inflammatory response following cardiac surgery, and the various therapeutic strategies being used to modulate this response.

Long-Term Neurodevelopmental Outcome and Exercise Capacity After Corrective Surgery for Tetralogy of Fallot or Ventricular Septal Defect in Infancy

BACKGROUND

The purpose of this prospective study was to assess whether neurodevelopmental status and exercise capacity of children 5 to 10 years after corrective surgery for tetralogy of Fallot or ventricular septal defect in infancy was different compared with normal children and influenced by the preoperative condition of hypoxemia or cardiac insufficiency.

METHODS

Forty unselected children, 20 with tetralogy of Fallot and hypoxemia and 20 with ventricular septal defect and cardiac insufficiency, operated on with combined deep hypothermic circulatory arrest and low flow cardiopulmonary bypass at a mean age of 0.7 +/- 0.3 years (mean +/- SD), underwent, at mean age 7.4 +/- 1.6 years, standardized evaluation of neurologic status, gross motor function, intelligence, academic achievement, language, and exercise capacity. Results were compared between the groups and related to preoperative, perioperative, and postoperative status and management.

RESULTS

Rate of mild neurologic dysfunction was increased compared with normal children, but not different between the groups. Exercise capacity and socioeconomic status were not different compared with normal children and between the groups. Compared with the normal population, motor function, formal intelligence, academic achievement, and expressive and receptive language were significantly reduced (p < 0.01 to p < 0.001) in the whole group and in the subgroups, except for normal intelligence in ventricular septal defect patients. Motor dysfunction was significantly higher in the Fallot group compared with the ventricular septal defect group (p < 0.01) and correlated with neurologic dysfunction, lower intelligence, and reduced expressive language (p < 0.05 each). Reduced New York Heart Association functional class was correlated with lower exercise capacity and longer duration of cardiopulmonary bypass (p < 0.05 each). Reduced socioeconomic status significantly influenced dysfunction in formal intelligence (p < 0.01) and academic achievement (p < 0.05). Preoperative risk factors such as prenatal hypoxia, perinatal asphyxia, and preterm birth, factors of perioperative management such as cardiac arrest, lowest nasopharyngeal temperature, and age at surgery, and postoperative risk factors as postoperative cardiocirculatory insufficiency and duration of mechanical ventilation were not different between the groups and had no influence on outcome. Degree of hypoxemia in Fallot patients and degree of cardiac insufficiency in ventricular septal defect patients did not influence the outcome within the subgroups.

CONCLUSIONS

Children with preoperative hypoxemia in infancy are at higher risk for motor dysfunction than children with cardiac insufficiency. Corrective surgery in infancy for tetralogy of Fallot or ventricular septal defect with combined circulatory arrest and low flow bypass is associated with reduced neurodevelopmental outcome, but not with reduced exercise capacity in childhood. In our experience, the general risk of long-term neurodevelopmental impairment is related to unfavorable effects of the global perioperative management. Socioeconomic status influences cognitive capabilities.