Risk factors for nosocomial infections after cardiac surgery in newborns with congenital heart disease

Association Between Postoperative Lymphocyte Count and the Occurrence of Infections After Pediatric Cardiac Surgery With Cardiopulmonary Bypass

OBJECTIVE

The objective of this study was to evaluate the association between the minimal count of lymphocyte (Ly_Min) after cardiac surgery with cardiopulmonary bypass and the occurrence of infections within the first 30 postoperative days (POD).

METHODS

From a local European Congenital Heart Surgeons Association (ECHSA) database, all cardiac surgeries with cardiopulmonary bypass in children under 18 years old between January 2014 and December 2021 were eligible. Infections occurring within 30 POD were prospectively recorded according to ECHSA definitions, and classified into sepsis, pneumonia, wound infection, mediastinitis or endocarditis. For each surgery, Ly_Min was collected during the first 2 POD and the optimal threshold for predicting infection was chosen using receiver operating characteristic curve analysis. Univariate and multivariate logistic regression analyses were performed to identify variables associated with the risk of infection.

RESULTS

Of 1428 surgeries conducted over the 8-year period, 111 (8%) were complicated by at least 1 infection, including pneumonia (n = 45), wound infection (n = 41), sepsis (n = 24), mediastinitis (n = 20) and endocarditis (n = 3). Mean Ly_Min in the first 2 POD was lower in the infected group compared with the noninfected group (1.32 ± 0.81 vs. 1.81 ± 1.05 × 109/L, P < 0.001). After adjusting for confounders, Ly_Min <1.105 × 109/L within the first 1 POD was independently associated with an increased risk of postoperative infections (adjusted odds ratio = 1.75, 95% confidence interval: 1.10-2.79, P = 0.019).

CONCLUSIONS

In this large single-center cohort of pediatric cardiac surgeries, Ly_Min during the first 2 POD was associated with the development of infections within 30 days after cardiopulmonary bypass.

Bloodstream Infections in Infants and Children With Congenital Heart Disease Undergoing Cardiac Surgery

BACKGROUND

Children with congenital heart disease undergoing cardiac surgery are at risk for laboratory-confirmed bloodstream infections (LCBIs). These infections can lead to morbidity, mortality, and increased health care costs. The role of mucosal barrier injury in causing LCBIs is unknown.

OBJECTIVES

To describe characteristics of LCBIs in patients admitted to cardiac intensive care and step-down units and to assess frequencies of National Healthcare Safety Network infection types and associations with organism classification, patient clinical factors, and infection outcomes.

METHODS

A retrospective cohort analysis using manual electronic medical record data abstraction included children with congenital heart disease who developed an LCBI while receiving inpatient cardiac care between August 2011 and November 2018 at one institution. Demographic, clinical, laboratory, and outcome variables were collected and analyzed with descriptive and inferential statistics.

RESULTS

Eighty-seven patients with congenital heart disease developed 103 LCBIs during the study time frame. The most common causative microorganisms were gram-positive bacteria, including Enterococcus faecalis and Staphylococcus epidermidis. Sixty-three percent of causative organisms were characterized as originating from mucosal barrier injury, although no infections met National Healthcare Safety Network criteria for mucosal barrier injury LCBIs.

CONCLUSIONS

Translocation of bacteria through injured gut mucosa may cause bloodstream infections in children with congenital heart disease. Further investigation is warranted to understand microbiome changes that adversely select pathogenic gut organisms. Preventive care to maintain intact gut function and a healthy microbiome should be explored for this patient population.

The influence of decreasing variable collection burden on hospital-level risk-adjustment

BACKGROUND

Risk-adjustment is a key feature of the American College of Surgeons National Surgical Quality Improvement Program-Pediatric (NSQIP-Ped). Risk-adjusted model variables require meticulous collection and periodic assessment. This study presents a method for eliminating superfluous variables using the congenital malformation (CM) predictor variable as an example.

METHODS

This retrospective cohort study used NSQIP-Ped data from January 1st to December 31st, 2019 from 141 hospitals to compare six risk-adjusted mortality and morbidity outcome models with and without CM as a predictor. Model performance was compared using C-index and Hosmer-Lemeshow (HL) statistics. Hospital-level performance was assessed by comparing changes in outlier statuses, adjusted quartile ranks, and overall hospital performance statuses between models with and without CM inclusion. Lastly, Pearson correlation analysis was performed on log-transformed ORs between models.

RESULTS

Model performance was similar with removal of CM as a predictor. The difference between C-index statistics was minimal (≤ 0.002). Graphical representations of model HL-statistics with and without CM showed considerable overlap and only one model attained significance, indicating minimally decreased performance (P = 0.058 with CM; P = 0.044 without CM). Regarding hospital-level performance, minimal changes in the number and list of hospitals assigned to each outlier status, adjusted quartile rank, and overall hospital performance status were observed when CM was removed. Strong correlation between log-transformed ORs was observed (r ≥ 0.993).

CONCLUSIONS

Removal of CM from NSQIP-Ped has minimal effect on risk-adjusted outcome modelling. Similar efforts may help balance optimal data collection burdens without sacrificing highly valued risk-adjustment in the future.

LEVEL OF EVIDENCE

Level II prognosis study.

Cell Saver Blood Reinfusion Up to 24 Hours Post Collection in Pediatric Cardiac Surgical Patients Does Not Increase Incidence of Hospital-Acquired Infections or Mortality

Cell saver blood reinfusion, a blood conservation technique recently available for pediatric use, is typically limited to 6 hours post processing to guard against bacterial contamination. We hypothesize that reinfusion of cell saver blood up to 24 hours post collection in children after cardiac surgery will not increase the incidence of hospital-acquired infections (HAI). The primary aim is to compare incidence of HAI between children receiving cell saver blood ≤6 hours vs. >6 to ≤24 hours from its collection. The secondary aim is to compare mortality and clinical outcomes. Retrospective chart review of children ≤18 years undergoing cardiac surgery with cardiopulmonary bypass (CPB) from 2013 to 2018 when cell saver collection and bedside temperature controlled storage became standard of care. Patients on extracorporeal membrane oxygenation (ECMO) within 48 hours postoperatively and those who did not receive cell saver were excluded. The primary outcome was HAI incidence postoperative days 0-6. Demographic data included diagnosis, surgical severity score, and clinical outcomes. 466 patients, 45% female. No significant between-group differences identified. There was no significant difference in HAI (control 8.5% vs. treatment 8.0%, p = .80) and death (control 7.9% vs. treatment 4.9%, p = .20). Noninferiority testing indicated the treatment group was not statistically inferior to the control group (p = .0028). Kaplan-Meier curve depicted similar status between-group rates of no infection or death; 92% treatment vs. 91% control. Total volume allogeneic red blood cell transfusion (allogeneic blood transfusion [ABT]) up to 24 hours postoperatively was significantly less in the treatment group, p < .0001. Incidence of HAI or mortality was not increased in patients receiving cell saver blood reinfusion >6 to ≤24 hours post collection. Treatment subjects received significantly less volume of ABT. Considering the risks of ABT, these findings support cell saver blood reinfusion up to 24 hours post collection.

Pulmonary infection after cardiopulmonary bypass surgery in children: a risk estimation model in China

OBJECTIVES

The occurrence of pulmonary infection after congenital heart disease (CHD) surgery can lead to significant increases in intensive care in cardiac intensive care unit (CICU) retention time, medical expenses, and risk of death risk. We hypothesized that patients with a high risk of pulmonary infection could be screened out as early after surgery. Hence, we developed and validated the first risk prediction model to verify our hypothesis.

METHODS

Patients who underwent CHD surgery from October 2012 to December 2017 in the Children's Hospital of Chongqing Medical University were included in the development group, while patients who underwent CHD surgery from December 2017 to October 2018 were included in the validation group. The independent risk factors associated with pulmonary infection following CHD surgery were screened using univariable and multivariable logistic regression analyses. The corresponding nomogram prediction model was constructed according to the regression coefficients. Model discrimination was evaluated by the area under the receiver operating characteristic curve (ROC) (AUC), and model calibration was conducted with the Hosmer-Lemeshow test.

RESULTS

The univariate and multivariate logistic regression analyses identified the following six independent risk factors of pulmonary infection after cardiac surgery: age, weight, preoperative hospital stay, risk-adjusted classification for congenital heart surgery (RACHS)-1 score, cardiopulmonary bypass time and intraoperative blood transfusion. We established an individualized prediction model of pulmonary infection following cardiopulmonary bypass surgery for CHD in children. The model displayed accuracy and reliability and was evaluated by discrimination and calibration analyses. The AUCs for the development and validation groups were 0.900 and 0.908, respectively, and the P-values of the calibration tests were 0.999 and 0.452 respectively. Therefore, the predicted probability of the model was consistent with the actual probability.

CONCLUSIONS

Identified the independent risk factors of pulmonary infection after cardiopulmonary bypass surgery. An individualized prediction model was developed to evaluate the pulmonary infection of patients after surgery. For high-risk patients, after surgery, targeted interventions can reduce the risk of pulmonary infection.

Microbial Contamination after Cardiac Surgery in a Hospital Cardiac Surgery Ward

Surgery site infection is one of the most common postoperative complications which is associated with increased morbidity, mortality and admission costs. It is considered a priority to determine the level of nosocomial infection and its control in reflecting the quality of care. Therefore, this study aimed to evaluate the microbial contamination after cardiac surgery at a hospital cardiac surgery ward of Besat Hospital, Tehran.

In this cross-sectional descriptive-analytic study (2013-2017), 610 patients underwent surgery at the Department of Cardiac Surgery of Besat Hospital. All necessary information such as urine culture, surgical site, histopathologic examination for the diagnosis of microbial contamination and microorganisms were collected from the patient records and inserted in the questionnaire. The data were analyzed using SPSS (version 25).

The incidence of nosocomial infections following cardiac surgery reportedly ranged from 17% to 23%. Accordingly, pneumonia (51.2%) and local infections (22%) were the most common infections in the studied population. The mortality rate in our population was 11.4%. Moreover, 64.3% of the total mortality cases were reported in patients with sepsis. The mean age and duration of admission of patients with catheter infection were significantly higher than other subjects.

Given the relatively high prevalence of the infection and its importance, it is necessary to take more serious measures to prevent and control these infections.

Low risk of necrotising enterocolitis in enterally fed neonates with critical heart disease: an observational study

OBJECTIVE

We aimed to investigate the frequency of necrotising enterocolitis (NEC) in infants with critical congenital heart disease (CCHD) hypothesising that preoperative enteral feeding does not increase the risk of NEC.

BACKGROUND

When NEC affects term infants, underlying risk factors such as asphyxia, sepsis or CCHD are often found. Due to fear of NEC development in infants with CCHD great caution is practised in many countries to defer preoperative enteral feeding, but in Sweden this is routinely provided.

DESIGN, SETTING AND PATIENTS

An observational study of all infants born with CCHD who were admitted to Queen Silvia Children's Hospital in Gothenburg between 2010 and 2017. The International Classification of Diseases 10th Revision diagnosis code of NEC was used to identify NEC cases in this group. Infants described as 'fully fed' or who were fed at least 45 mL/kg/day before cardiac surgery were identified.

MAIN OUTCOME MEASURES

NEC in infants with CCHD in relation to preoperative enteral feeding.

RESULTS

There were 458 infants with CCHD admitted during the study period. 408/458 were born at term and 361/458 required prostaglandin E1 before surgery. In total, 444/458 infants (97%) were fully fed or fed at least 45 mL/kg daily before cardiac surgery. Four of 458 infants developed NEC (0.9%). All four had other risk factors for NEC.

CONCLUSIONS

This study showed a low risk of NEC in term infants fed enterally before cardiac surgery. We speculate that preoperative enteral feeding of neonates with CCHD does not increase the risk of NEC development.

Bloodstream infections during post-cardiotomy extracorporeal membrane oxygenation: Incidence, risk factors, and outcomes

Introduction:

Veno-arterial extracorporeal membrane oxygenation after heart surgery is a relatively common procedure. It is easily applicable but associated with a number of complications, including bloodstream infections. The aim of this study is to determine the current rate and the risk factors related to bloodstream infections acquired during post-cardiotomy veno-arterial extracorporeal membrane oxygenation.

Methods:

Single-center retrospective study. From the overall population receiving any kind of extracorporeal membrane oxygenation from March 2013 through December 2017, the post-cardiotomy patient population was extracted, with a final sample of 92 veno-arterial extracorporeal membrane oxygenations. The risk of developing bloodstream infections as a function of extracorporeal membrane oxygenation exposure was analyzed with appropriate statistical analyses, including a Kaplan–Meier analysis.

Results:

Overall, 14 (15.2%) patients developed a bloodstream infection during extracorporeal membrane oxygenation or within the first 48 h after extracorporeal membrane oxygenation removal. The total extracorporeal membrane oxygenation duration in the population was 567 days, and the incidence of bloodstream infections was 24.7 bloodstream infections/1000 extracorporeal membrane oxygenation days. There was a progressive increase in the cumulative hazard ratio during the first 7 days, reaching a value of 20% on day 7; from day 7 and day 15, the hazard ratio remained stable, with a second increase after day 15. The independent risk factors associated with bloodstream infections were adult age, pre-implantation serum total bilirubin level, and the amount of chest drain blood loss.

Discussion:

Infections acquired during veno-arterial extracorporeal membrane oxygenation are common. Identify the risk factors that may improve strategies for treatment and prevention.