Bedside prediction rule for infections after pediatric cardiac surgery

Endocytosis of peroxiredoxin 1 links sterile inflammation to immunoparalysis in pediatric patients following cardiopulmonary bypass

After cardiopulmonary bypass (CPB), the occurrence of systemic inflammatory response is often accompanied by a persistent compensatory anti-inflammatory response syndrome that can lead to a compromised immune competence termed immunoparalysis, rendering the patients susceptible to infections which is a leading complication following cardiac surgery. However, the underlying mechanisms of CPB-elicited immunoparalysis remain obscure. In this study we showed that peroxiredoxin 1 (Prdx1), a putative cytosolic antioxidant, was released immediately after CPB in a cohort of pediatric patients receiving congenital cardiac surgery. This increased Prdx1 was correlated to a reduced human leukocyte antigen-DR expression and an elevated interleukin-10 (IL-10) production, as well as a hypo-responsiveness of macrophages to endotoxin and a higher incidence of nosocomial infection. We demonstrated that substitution of Ser⁸³ for Cys⁸³ prevented Prdx1 from oligomerization and subsequent binding and internalization to macrophages. These effects mitigated Prdx1-induced IL-10 induction and endotoxin tolerance. Furthermore, after engagement with toll-like receptor (TLR) 4, clathrin-dependent endocytosis is crucial for Prdx1 to elicit IL-10 production in phagocytes. Congruently, inhibition of Prdx1/TLR4 endocytosis in phagocytes reversed the Prdx1/IL-10-mediated hypo-responsiveness to endotoxin. Our findings unveiled the possible mechanisms by which Prdx1 undertakes to cause immunoparalysis, and targeting endocytosis of Prdx1 could be a novel therapeutic approach for postoperative infections associated with CPB.

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Cardiopulmonary bypass-elicited ischemia/reperfusion injury causes release of Prdx1.

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High molecular weight forms of Prdx1 interact with TLR4 to initiate sterile inflammation.

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Endocytosis of Prdx1/TLR4 induces IL-10 production that leads to immunoparalysis and subsequent septic inflammation.

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Inhibition of Prdx1/TLR4 endocytosis reverses Prdx1/IL-10-mediated hypo-responsiveness to endotoxin in phagocytes.

Extracardiac Complications in Intensive Care Units after Surgical Repair for Congenital Heart Disease: Imaging Review with a Focus on Ultrasound and Radiography

Pediatric patients show various extracardiac complications after cardiovascular surgery, and radiography and ultrasound are routinely performed in the intensive care unit to detect and evaluate these complications. This review presents images of these complications, sonographic approach, and timing of occurrence that are categorized based on their extracardiac locations and include complications pertaining to the central nervous system, mediastinum, thorax and lung parenchyma, diaphragm, liver and biliary system, and kidney along with pleural effusion and iatrogenic complications. This pictorial review will make it easier for medical doctors in intensive care units to identify and manage various extracardiac complications in pediatric patients after cardiovascular surgery.

A Systematic Review of Antibiotic Prophylaxis for Delayed Sternal Closure in Children

Antibiotic prophylaxis following delayed sternal closure in pediatric cardiac surgery is not standardized. We systematically reviewed relevant literature published between 1990 and 2019 to aid future trial design. Patient characteristics, antimicrobial prophylaxis regimens, and postoperative incidence of infection were collected. Twenty-eight studies described 36 different regimens in over 3,000 patients. There were 11 single-drug regimens and 25 multidrug regimens. Cefazolin-only was the most common regimen (9/36, 25%). The overall incidence of surgical site infection was 7.5% (217/2,910 patients) and bloodstream infection was 7.4% (123/1,667 patients). In the 2010s, multidrug regimens were associated with a significantly lower incidence of both surgical site infections (4.6% vs. 20%, P < .001) and bloodstream infections (6.0% vs. 50%, P < .001) compared to single-drug regimens.

Creation of a severity index for hidradenitis suppurativa that includes a validated quality-of-life measure: the HIDRAscore

Background

Hidradenitis suppurativa (HS) is a chronic, debilitating disease with a considerable effect on patient quality of life. Its clinical severity can be measured using different scoring systems; however, few of them include patient‐centred parameters.

Objective

To create a new scoring system for HS that includes a quality‐of‐life instrument, the HIDRAdisk.

Methods

This post hoc analysis was carried out within the framework of a multicentre, longitudinal, epidemiologic study conducted over 9 months on quality‐of‐life aspects of HS. The new severity score was created using as reference a question from the Subject Satisfaction Questionnaire (SSQ) concerning the severity of HS as evaluated by the patient. Associated variables were selected using univariable and multivariable logistic regression models. The discriminant capabilities of the final model and of the final score were evaluated by the area under the receiver operating characteristic curve and the Hosmer–Lemeshow test.

Results

The study population included 308 patients with HS of any severity grade. According to the results of the regression models, the variables associated with the reference SSQ measure were number of inflammatory nodules, abscesses and draining fistulas; the HIDRAdisk score; and the number of subumbilical lesions. The HIDRAscore is obtained by the sum of the scores associated with the number of these parameters. Possible scores range from 0 to 10.

Conclusion

The HIDRAscore is a new scoring system for HS severity which, in addition to the clinical evaluation by the physician, includes a validated patient‐reported outcome measure, the HIDRAdisk.

Acute kidney injury is associated with subsequent infection in neonates after the Norwood procedure: a retrospective chart review

BACKGROUND

Acute kidney injury (AKI) and infection are common complications after pediatric cardiac surgery. No pediatric study has evaluated for an association between postoperative AKI and infection. The objective of this study was to determine if AKI in neonates after cardiopulmonary bypass was associated with the development of a postoperative infection.

METHODS

We performed a single center retrospective chart review from January 2009 to December 2015 of neonates (age ≤ 30 days) undergoing the Norwood procedure. AKI was defined by the modified neonatal Kidney Disease Improving Global outcomes serum creatinine criteria using (1) measured serum creatinine and (2) creatinine corrected for fluid balance on postoperative days 1-4. Infection, (culture positive or presumed), must have occurred after a diagnosis of AKI and within 60 days of surgery.

RESULTS

Ninety-five patients were included, of which postoperative infection occurred in 42 (44%). AKI occurred in 38 (40%) and 42 (44%) patients by measured serum creatinine and fluid overload corrected creatinine, respectively, and was most commonly diagnosed on postoperative day 2. The median time to infection from the time of surgery and AKI was 7 days (IQR 5-14 days) and 6 days (IQR 3-13 days), respectively. After adjusting for confounders, the odds of a postoperative infection were 3.64 times greater in patients with fluid corrected AKI (95% CI, 1.36-9.75; p = 0.01).

CONCLUSIONS

Fluid corrected AKI was independently associated with the development of a postoperative infection. These findings support the notion that AKI is an immunosuppressed state that increases the risk of infection.

Risk Factors for Healthcare-Associated Infections After Pediatric Cardiac Surgery

OBJECTIVES

Healthcare-associated infections after pediatric cardiac surgery are significant causes of morbidity and mortality. We aimed to identify the risk factors for the occurrence of healthcare-associated infections after pediatric cardiac surgery.

DESIGN

Retrospective, single-center observational study.

SETTING

PICU at a tertiary children's hospital.

PATIENTS

Consecutive pediatric patients less than or equal to 18 years old admitted to the PICU after cardiac surgery, between January 2013 and December 2015.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

All the data were retrospectively collected from the medical records of patients. We assessed the first surgery during a single PICU stay and identified four common healthcare-associated infections, including bloodstream infection, surgical site infection, pneumonia, and urinary tract infection, according to the definitions of the Centers for Disease Control and Prevention and National Healthcare Safety Network. We assessed the pre-, intra-, and early postoperative potential risk factors for these healthcare-associated infections via multivariable analysis. In total, 526 cardiac surgeries (394 patients) were included. We identified 81 cases of healthcare-associated infections, including, bloodstream infections (n = 30), surgical site infections (n = 30), urinary tract infections (n = 13), and pneumonia (n = 8). In the case of 71 of the surgeries (13.5%), at least one healthcare-associated infection was reported. Multivariable analysis indicated the following risk factors for postoperative healthcare-associated infections: mechanical ventilation greater than or equal to 3 days (odds ratio, 4.81; 95% CI, 1.89-12.8), dopamine use (odds ratio, 3.87; 95% CI, 1.53-10.3), genetic abnormality (odds ratio, 2.53; 95% CI, 1.17-5.45), and delayed sternal closure (odds ratio, 3.78; 95% CI, 1.16-12.8).

CONCLUSIONS

Mechanical ventilation greater than or equal to 3 days, dopamine use, genetic abnormality, and delayed sternal closure were associated with healthcare-associated infections after pediatric cardiac surgery. Since the use of dopamine is an easily modifiable risk factor, and may serve as a potential target to reduce healthcare-associated infections, further studies are needed to establish whether dopamine negatively impacts the development of healthcare-associated infections.

Perioperative infections in congenital heart disease

BACKGROUND

Perioperative infections have significant consequences for children with congenital heart disease (CHD), which can manifest as acute or chronic infection followed by poor growth and progressive cardiac failure. The consequences include delayed or higher-risk surgery, and increased postoperative morbidity and mortality.

METHODS

A systematic search for studies evaluating the burden and interventions to reduce perioperative infections in children with CHD was undertaken using PubMed.

RESULTS

Limited studies conducted in low- to middle-income countries demonstrated the large burden of perioperative infections among children with CHD. Most studies focussed on infections after surgery. Few studies evaluated strategies to prevent preoperative infection or the impact of infection on decision-making around the timing of surgery. Children with CHD have multiple risk factors for infections including delayed presentation, inadequate treatment of cardiac failure, and poor nutrition.

CONCLUSIONS

The burden of perioperative infections is high among children with CHD, and studies evaluating the effectiveness of interventions to reduce these infections are lacking. As good nutrition, early corrective surgery, and measures to reduce nosocomial infection are likely to play a role, practical steps can be taken to make surgery safer.

Applying vacuum to accomplish reduced wound infections in laparoscopic pediatric surgery

INTRODUCTION

The prevention of surgical site infections has received little attention in pediatric surgery. Negative pressure wound therapy is used to treat complex wounds. We hypothesized that this principle could reduce wound infection rates following laparoscopic surgery. We tested this in a randomized controlled trial.

MATERIALS AND METHODS

We randomized pediatric patients with an umbilical port site to a standard dressing or a vacuum dressing. The dressings were removed 48h after surgery. A nurse blinded for the treatment inspected the umbilical wound between post-operative days 7-10 for infection. Data comparison was performed using a Fisher exact test with p<0.05 defined as significant.

RESULTS

We recruited 90 patients over 2 years and randomized 44 to the vacuum dressing arm and 42 to the control arm. We observed a 2.8% (n=1/35) infection rate in the vacuum dressing group and 3.3% (n=1/30) in the control group (p=1.0).

DISCUSSION

We ended our study early when an interim analysis showed an impractical number of patients would be required to achieve sufficient power. We did not find a significant difference between the control and vacuum dressings in reducing post-operative wound infections.

LEVEL OF EVIDENCE

3.

Immunologic and Infectious Diseases in Pediatric Cardiac Critical Care: Proceedings of the 10th International Pediatric Cardiac Intensive Care Society Conference

Since the inception of the Pediatric Cardiac Intensive Care Society (PCICS) in 2003, remarkable advances in the care of children with critical cardiac disease have been developed. Specialized surgical approaches, anesthesiology practices, and intensive care management have all contributed to improved outcomes. However, significant morbidity often results from immunologic or infectious disease in the perioperative period or during a medical intensive care unit admission. The immunologic or infectious illness may lead to fever, which requires the attention and resources of the cardiac intensivist. Frequently, cardiopulmonary bypass leads to an inflammatory state that may present hemodynamic challenges or complicate postoperative care. However, inflammation unchecked by a compensatory anti-inflammatory response may also contribute to the development of capillary leak and lead to a complicated intensive care unit course. Any patient admitted to the intensive care unit is at risk for a hospital acquired infection, and no patients are at greater risk than the child treated with mechanical circulatory support. In summary, the prevention, diagnosis, and management of immunologic and infectious diseases in the pediatric cardiac intensive care unit is of paramount importance for the clinician. This review from the tenth PCICS International Conference will summarize the current knowledge in this important aspect of our field.

Urinary tract infection in children after cardiac surgery: Incidence, causes, risk factors and outcomes in a single-center study

Nosocomial urinary tract infection (UTI) increases hospitalization, cost and morbidity. In this cohort study, we aimed to determine the incidence, risk factors, etiology and outcomes of UTIs in post-operative cardiac children. To this end, we studied all post-operative patients admitted to the Pediatric Cardiac Intensive Care Unit (PCICU) in 2012, and we divided the patients into two groups: the UTI (UTI group) and the non-UTI (control group). We compared both groups for multiple peri-operative risk factors. We included 413 children in this study. Of these, 29 (7%) had UTIs after cardiac surgery (UTI group), and 384 (93%) were free from UTIs (control group). All UTI cases were catheter-associated UTIs (CAUTIs). A total of 1578 urinary catheter days were assessed in this study, with a CAUTI density rate of 18 per 1000 catheter days. Multivariate logistic regression analysis demonstrated the following risk factors for CAUTI development: duration of urinary catheter placement (p<0.001), presence of congenital abnormalities of kidney and urinary tract (CAKUT) (p<0.0041) and the presence of certain syndromes (Down, William, and Noonan) (p<0.02). Gram-negative bacteria accounted for 63% of the CAUTI. The main causes of CAUTI were Klebsiella (27%), Candida (24%) and Escherichia coli (21%). Resistant organisms caused 34% of CAUTI. Two patients (7%) died in the UTI group compared with the one patient (0.3%) who died in the control group (p<0.05). Based on these findings, we concluded that an increased duration of the urinary catheter, the presence of CAKUT, and the presence of syndromes comprised the main risk factors for CAUTI. Gram-negative organisms were the main causes for CAUTI, and one-third of them found to be resistant in this single-center study.

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.

Evaluation of the relationship between plasma transfusion and nosocomial infection after cardiac surgery in children younger than 1 year

OBJECTIVES

Recent data have suggested a link between plasma transfusion and the development of nosocomial infections in critically ill children. However, to our knowledge, no study has specifically focused on this association among children undergoing cardiac surgery. Thus, the main objective of this study was to analyze the relationship between plasma transfusion after cardiac surgery and the risk of nosocomial infections, including bloodstream infections, mediastinitis, and ventilator-associated pneumonia, in children younger than 1 year.

DESIGN

Observational single-center study.

SETTING

A 12-bed tertiary PICU in a university hospital in France.

PATIENTS

Children less than 1 year admitted after cardiac surgery under cardiopulmonary bypass between November 2007 and December 2012.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Data from 233 children were analyzed, of which 94 children (40%) had been transfused with plasma during their PICU stay. Fifty-six episodes of nosocomial infections (51 children) were reported, yielding a nosocomial infection ratio of 24%. The unadjusted odds ratio for developing nosocomial infections associated with plasma transfusion was 4.1 (95% CI, 2.1-7.9; p < 0.001). After adjusting for a propensity score, there was no difference between the two groups (adjusted odds ratio, 1.5; 95% CI, 0.5-4.0; p = 0.5).

CONCLUSION

Plasma transfusion following cardiac surgery under cardiopulmonary bypass was not independently associated with the development of nosocomial infections in children (< 1 yr old) after adjustment for a propensity score.

Blood stream infection in patients undergoing systematic off-pump coronary artery bypass: incidence, risk factors, outcome, and associated pathogens

BACKGROUND

Blood stream infection (BSI) is a major cause of mortality and morbidity for patients undergoing cardiac surgery. However, information is lacking about patients undergoing off-pump coronary artery bypass (OPCAB). The purpose of this study was to assess the incidence, risk factors, outcome and associated pathogens of BSI after OPCAB.

METHODS

One thousand ten consecutive patients undergoing OPCAB between 2001 and 2012 were included in a retrospective case-control study. A propensity-matched control was used for risk factor analysis.

RESULTS

Of the 1,010 patients, 26 patients (2.6%) had 32 episodes of BSI after surgery, which occurred at a median of 14 d after surgery. Gram-negative bacilli and gram-positive cocci were distributed equally. Methicillin-resistant Staphylococcus aureus was the pathogen identified most frequently, and the most common source of infection was a surgical site. The hospital mortality rate was 54%. By univariable analysis, diabetes mellitus, pre-operative renal impairment, pre-operative low hemoglobin, pre-operative endotracheal intubation, dialysis before or after surgery, cardiogenic shock, left ventricular ejection fraction of less than 40%, non-elective surgery, low number of distal anastomoses, atrial fibrillation after surgery, and re-operation for bleeding were significant risk factors. By multivariable analysis, the independent risk factors were left ventricular ejection fraction of less than 40%, low number of distal anastomoses, atrial fibrillation after surgery, and dialysis after surgery.

CONCLUSIONS

Blood stream infections remained a common complication after OPCAB, and the mortality was high. Gram-negative bacilli and gram-positive cocci were distributed equally. Methicillin-resistant S. aureus was the pathogen identified most frequently. Preventive tactics should target likely pathogens and high-risk patients undergoing OPCAB.

Postoperative differences between colonization and infection after pediatric cardiac surgery-a propensity matched analysis

Background

The objective of this study was to identify the postoperative risk factors associated with the conversion of colonization to postoperative infection in pediatric patients undergoing cardiac surgery.

Methods

Following approval from the Institutional Review Board, patient demographics, co-morbidities, surgery details, transfusion requirements, inotropic infusions, laboratory parameters and positive microbial results were recorded during the hospital stay, and the patients were divided into two groups: patients with clinical signs of infection and patients with only positive cultures but without infection during the postoperative period. Using propensity scores, 141 patients with infection were matched to 141 patients with positive microbial cultures but without signs of infection. Our database consisted of 1665 consecutive pediatric patients who underwent cardiac surgery between January 2004 and December 2008 at a single center. The association between the patient group with infection and the group with colonization was analyzed after propensity score matching of the perioperative variables.

Results

179 patients (9.3%) had infection, and 253 patients (15.2%) had colonization. The occurrence of Gram-positive species was significantly greater in the colonization group (p = 0.004). The C-reactive protein levels on the first and second postoperative days were significantly greater in the infection group (p = 0.02 and p = 0.05, respectively). The sum of all the positive cultures obtained during the postoperative period was greater in the infection group compared to the colonization group (p = 0.02). The length of the intensive care unit stay (p < 0.001) was significantly longer in the infection group compared to the control group.

Conclusions

Based on our results, we uncovered independent relationships between the conversion of colonization to infection regarding positive S. aureus and bloodstream results, as well as significant differences between the two groups regarding postoperative C-reactive protein levels and white blood cell counts.