Risk factors for surgical site infection after delayed sternal closure

Impact of delayed sternal closure on wound infections following neonatal and infant cardiac surgery

Objectives

Delayed sternal closure is a routine procedure to reduce hemodynamic and respiratory instability in pediatric patients following cardiac surgery, particularly in neonates and infants. In this setting, the possible links between sternal wound infection and delayed sternal closure are still a matter of debate. As a part of our routine, there was a low threshold for delayed sternal closure, so we reviewed our experience with sternal wound infections with a focus on potentially related perioperative risk factors, particularly delayed sternal closure.

Methods

We retrospectively identified 358 operated neonates (37%) and infants (mean age 3.6 months) in our local congenital heart disease database between January 2013 and June 2017. Potential risk factors for sternal wound infections, such as age, gender, complexity (based on Aristotle- and STS-EACTS mortality category), reoperation, use of cardiopulmonary bypass, extracorporeal membrane oxygenation, mortality and delayed sternal closure (163/358, 46%), were subjected to uni- and multivariate analysis.

Results

A total of 26/358 patients (7.3%) developed a superficial sternal wound infection. There were no deep sternal wound infections, no mediastinitis or sepsis. Applying univariate analysis, the prevalence of sternal wound infections was related to younger age, more complex surgery and delayed sternal closure. However, in multivariate analysis, sternal wound infection was only associated with delayed sternal closure (p = 0.013, odds ratio 8.6). Logistic regression revealed the prevalence of delayed sternal closure to be related to younger age, complexity, and the use of extracorporeal membrane oxygenation.

Conclusion

In patients younger than one year, sternal wound infections are clearly related to delayed sternal closure. However, in our cohort, all sternal wound infections were superficial and acceptable, considering the improved postoperative hemodynamic stability.

The solvent effect modulates the formation of homogeneous polyphenol composite hydrogels with improved transparency and mechanical strength for antibacterial delayed sternal closure films

The usage of delayed sternal closure films after thoracotomy surgery helps doctors deal with emergency conveniently. There is a growing demand to develop suturable, antibacterial and transparent films for delayed sternal closure. Although polyphenol incorporated hydrogels provide good suture ability, they lose transparency because of the heterogeneous distribution of polyphenols during the post-immersion process. Here, a solvent exchange method is proposed to fabricate homogeneous polyphenol composite hydrogels in a bottom-up manner, which utilizes the distinct solvent effect of DMSO and H₂O to modulate the association and disassociation between polyphenols and the polymer backbones on demand. DMSO first provides a protective environment to turn off the intermolecular interactions and allows tannic acid (TA) to be dispersed into the polymer network PEG-lysozyme (PEG-LZM) homogeneously. The following water rehydration turns on the intermolecular interactions between titanic acid and PEG-lysozymes, and results in a homogeneous titanic acid toughened composite hydrogel (PEG-LZM-TA (DH)), which has an improved transparency and mechanical properties than those of the materials prepared by the post-immersion method. In addition, the TA integration provides antibacterial function to the hydrogels. We establish a rabbit delayed sternal closure model to demonstrate that PEG-LZM-TA (DH) films can be sutured to temporarily close the thoracic cavity of rabbits, provide a transparent window to inspect the wound at any time, and control the bacterial contamination efficiently. We further explore the solvent exchange method to other polyphenols and polymeric hydrogel composites. The results suggest that the solvent exchange method provides generic opportunities to fabricate homogeneous polyphenol strengthened hydrogel systems with high performance.

Nosocomial Infections During Extracorporeal Membrane Oxygenation in Pediatric Patients: A Multicenter Retrospective Study

OBJECTIVE

Extracorporeal membrane oxygenation (ECMO) is increasingly used in critically ill patients with respiratory and/or cardiac failure. This study aimed to investigate the epidemiology and risk factors of nosocomial infection (NI) in pediatric patients who underwent ECMO for respiratory and/or circulatory failure.

METHODS

Medical records for patients that were administered underwent ECMO support at Xiangya Second Hospital of Central South University, The Sixth Medical Center of PLA General Hospital, and Children's Hospital Affiliation of Zhengzhou University, from September 2012 to December 2019 were retrospectively reviewed. Clinical data of the patients who developed NI were collected and analyzed. Univariate and multivariate logistic regressions were performed to identify the independent predictive factors of NI during ECMO.

RESULTS

A total of 54 first episodes of NI were identified in the 190 patients on ECMO, including 32 cases of respiratory tract infections, 20 cases of bloodstream infections, and 2 cases of surgical site wound infections. Gram-negative pathogens were the dominant pathogens isolated, accounting for 92.6% of the NI. The incidence of ECMO-related NI was 47.6 cases per 1,000 ECMO days. In the univariate logistic regression, ECMO mode, ECMO duration, ICU duration, and peritoneal dialysis were associated with the development of NI in patients with ECMO support. However, in the multivariate analysis, only ECMO duration (OR = 2.46, 95%CI: 1.10, 5.51; P = 0.029), ICU duration (OR = 1.35, 95%CI: 1.05, 1.59; P = 0.017) and peritoneal dialysis (OR = 2.69, 95%CI: 1.08, 5.73; P = 0.031) were the independent predictive factors for NI during ECMO support.

CONCLUSION

This study identified the significant correlation between ECMO-related NI and ECMO duration, ICU duration, and peritoneal dialysis. Appropriate preventive measures are needed for hospitals to reduce the incidence of ECMO in pediatric patients.

Efforts to Reduce Infections in Delayed Sternal Closure Patients: A Survey of Pediatric Practice

BACKGROUND

Pediatric patients with sternum left open after cardiac surgery experience a higher risk for sternal wound infection (SWI). These infections are costly for programs, payers, and patients and their families. Despite efforts by individual programs to reduce infections in patients undergoing delayed sternal closure (DSC), there are no established guidelines that address preventive procedures. The purpose of this study was to determine the practice of pediatric cardiac surgery programs to prevent infection in their DSC patients and if preventive measures were associated with less infections.

METHODS

A 33 question survey on institutional practices was sent to chief surgeons at pediatric cardiac surgery programs in the United States.

RESULTS

Twenty-eight (35%) surgical programs responded. The mean number of pediatric cardiac bypass operations performed by programs in 2016 was 227 (range: 69-872). Data represented 6,484 patients <18 years of age who underwent cardiac surgery with 807 (12%) of those undergoing DSC. One hundred fifty-eight (2.4%) of all patients and 51 (6.3%) of the DSC patients developed a SWI. Patients with DSC who received preoperative baths were less likely to become infected (5.9% vs 15.8%; P = .015). Patients in programs with feeding protocols had fewer infections (5.7% vs 14.8%; P = .008).

CONCLUSIONS

The results of this survey of children's cardiac surgery programs describe their practices to reduce infection rates in DSC patients. A multicenter project on wound care and closure techniques that might impact this costly complication is needed.

A Quality Improvement Initiative to Reduce Surgical Site Infections in Patients Undergoing Delayed Sternal Closure After Pediatric Cardiac Surgery

Sternal wound infections (SWI) in delayed sternal closure (DSC) patients are a healthcare burden after congenital heart surgery. There are no guidelines specific for pediatric DSC patients to prevent this costly complication. The hypothesis was that the modifications to a bundled approach for DSC patients would decrease the SWI rate. For this prospective cohort study, DSC patients were postoperatively admitted to a pediatric cardiac care unit from February 2017 to January 2018. Using a modified protocol for prevention of SWI, the infection rates pre- and post-modified protocol were compared. The primary outcome measure was SWI. Secondary outcome measures were compliance with modifications. Retrospective review of cases in pre-protocol modification era from January 1, 2014 to December 31, 2016 showed 377 pediatric cardiopulmonary bypass cases and 39 (10.4%) underwent DSC. During the post-protocol modification era, there were 129 cardiopulmonary bypass cases and 17 (13%) DSC cases. The SWI rate in DSC were 7.7% and 0% for pre-intervention and post-intervention, respectively (p = 0.52). The Bayesian confidence interval with Jeffreys prior gives a 95% confidence interval of 1.5% to 18.3% for pre-intervention and 0 to 13.5% for post-intervention. Compliance with the protocol bundle during the post protocol era was 93-100%. Although preliminary results are not statistically significant due to cohort size, the economic burden and increased LOS for each SWI is clinically significant. The early results of reduced infections for DSC patients using a modified bundle approach appear promising. Continued study and a multicenter project would be beneficial.

Antibiotic Prophylaxis for Open Chest Management After Pediatric Cardiac Surgery

OBJECTIVES

Although open chest management optimizes hemodynamics after cardiac surgery, it increases postoperative infections and leads to increased mortality. Despite the importance of antibiotic prophylaxis during open chest management, no specific recommendations exist. We aimed to compare the occurrence rates of bloodstream infection and surgical site infection between the different prophylactic antibiotic regimens for open chest management after pediatric cardiac surgery.

DESIGN

Retrospective, single-center, observational study.

SETTING

PICU at a tertiary children's hospital.

PATIENTS

Consecutive patients younger than or equal to 18 years old with open chest management after cardiac surgery followed by delayed sternal closure, between January 2012 and June 2018.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We compared the composite occurrence rate of postoperative bloodstream infection and surgical site infection within 30 days after cardiac surgery between three prophylactic antibiotic regimens: 1) cefazolin, 2) cefazolin + vancomycin, and 3) vancomycin + meropenem. In 63 pediatric cardiac surgeries with open chest management, 17 bloodstream infections, and 12 surgical site infections were identified postoperatively. The composite occurrence rates of bloodstream infection and surgical site infection were 10 of 15 (67%), 10 of 19 (53%), and nine of 29 (31%) in the cefazolin, cefazolin + vancomycin, and vancomycin + meropenem regimens, respectively (p = 0.07). After adjusting for age, open chest management duration, extracorporeal membrane oxygenation use, and nasal methicillin-resistant Staphylococcus aureus colonization in multivariable analysis, there was no significant difference between the cefazolin and the cefazolin + vancomycin regimens (p = 0.19), while the vancomycin + meropenem regimen had a lower occurrence rate of bloodstream infection and surgical site infection than the cefazolin regimen (odds ratio, 0.0885; 95% CI, 0.0176-0.446; p = 0.003).

CONCLUSIONS

In this study, a lower occurrence rate of postoperative bloodstream infection and surgical site infection was observed among patients with broad-spectrum antibiotic regimen after pediatric cardiac surgery with open chest management. Further studies, ideally randomized controlled studies investigating the efficacy of broad-spectrum antibiotics and their complications, are warranted before routine implementation of broad-spectrum prophylactic antibiotic regimen.

Outcomes of Delayed Sternal Closure in Pediatric Heart Surgery: Single-Center Experience

Background

Delayed sternal closure (DSC) after cardiac surgery is a therapeutic option in the treatment of the severely impaired heart in pediatric cardiac surgery.

Methods

A single-center retrospective review of all bypass surgeries performed over a 10-year period (2003–2012).

Results

Of a total of 2325 patients registered in our database, the DSC group included 259 cases (11%), and the remaining 2066 cases (89%) constituted the control group (PSC). RACHS-1 risk was higher for the DSC group (74% had a score of 3 or 4) than for the PSC group (82% had a score of 2 or 3). The most frequent diagnosis for the DSC group was transposition of the great arteries (28%). We found out that hemodynamic instability was the main indication observed in patients aged ≤ 8 years (63%), while bleeding was the principal indication for patients aged ≥ 8 years (94%) (p ≤ 0.001). The average time between surgery and sternal closure was 2.3 ± 1.4 days. Overall mortality rates were higher for patients of the DSC group (22%) than for the PSC group (8.7%) (OR: 0.4 (95% CI: 0.4 to 0.5), p < 0.05). There were six patients with DSC who developed mediastinitis (2.3%). The risk of mediastinitis was significantly higher when DSC was performed 4 days after the primary surgery.

Conclusions

DSC is an important management strategy for congenital cardiac surgery in infants and children. The prolonged sternal closure time is associated with an increased rate of postoperative mediastinitis.

Impact of Delayed Chest Closure on Surgical Site Infection After Lung Transplantation

BACKGROUND

Delayed chest closure is an increasingly used approach in the management of bleeding and hemodynamic instability after lung transplantation. We sought to evaluate the impact of delayed chest closure on surgical site infection.

METHODS

We performed a single-center retrospective cohort study and included adult patients who received a lung transplant at our center between January 1, 2010, and July 31, 2014. We defined surgical site infection as a thoracotomy incision wound or pleural space infection. Follow-up was complete through 6 months after transplantation. We used logistic regression models to examine the impact of delayed chest closure on surgical site infection and to identify other potential risk factors.

RESULTS

During the study period, 67 of the 232 transplant procedures (29%) required delayed chest closure, and surgical site infection developed in 22 recipients (9%). Among the patients with surgical site infection, 18 experienced a wound infection, and 8 experienced a pleural space infection; 4 experienced concomitant wound and pleural space infection. Among the 67 who underwent delayed chest closure, 13 patients (19%) experienced a surgical site infection compared with 9 of the 165 patients (5%) who underwent primary closure (p = 0.001). In multivariate analysis, delayed chest closure was an independent risk factor for surgical site infection.

CONCLUSIONS

Although delayed chest closure may have an important role in the immediate management of recipients of a lung transplant, it is an independent risk factor for surgical site infection, and this is associated with increased morbidity.

Perioperative antibiotics in pediatric cardiac surgery: protocol for a systematic review

BACKGROUND

Post-operative infections in pediatric cardiac surgery are an ongoing clinical challenge, with rates between 1 and 20%. Perioperative antibiotics remain the standard for prevention of surgical-site infections, but the type of antibiotic and duration of administration remain poorly defined. Current levels of practice variation through informal surveys are very high. Rates of antibiotic-resistant organisms are increasing steadily around the world.

METHODS/DESIGN

We will identify all controlled observational studies and randomized controlled trials examining prophylactic antibiotic use in pediatric cardiac surgery. Data sources will include MEDLINE, EMBASE, CENTRAL, and proceedings from recent relevant scientific meetings. For each included study, we will conduct duplicate independent data extraction, risk of bias assessment, and evaluation of quality of evidence using the GRADE approach.

DISCUSSION

We will report the results of this review in agreement with the PRISMA statement and disseminate our findings at relevant critical care and cardiology conferences and through publication in peer-reviewed journals. We will use this systematic review to inform clinical guidelines, which will be disseminated in a separate stand-alone publication.

STUDY REGISTRATION NUMBER

PROSPERO CRD42016052978C.

Cardiothoracic surgical site phaeohyphomycosis caused by Bipolaris mould, multiple US states, 2008-2013: a clinical description

Bipolaris mould surgical site infections (SSIs) are exceedingly rare. We describe 21 cases of Bipolaris SSIs in pediatric and adult cardiothoracic surgery patients at ten hospitals in Texas, Arkansas, and Florida during 2008-2013. Median case-patient age was 55 years (range: 3 days-82 years), and 19 (90%) were male. Ten (48%) had coronary artery bypass or valve surgery, and seven (33%) had heart transplantation. Fifteen (71%) had more than one cardiothoracic procedure (median: 3, range: 1-11). Thirteen (62%) case-patients (all 5 pediatric patients, and 8 (50%) of 16 adult patients) had delayed sternal closure (chest closed >1 day [median = 8 days; range: 2-22] following the initial cardiothoracic procedure). Thirteen (62%) had mediastinitis. Median time from initial surgery to positive Bipolaris culture was 20 days (range: 6-497). Sixteen (76%) case-patients died.

Significance of positive mediastinal cultures in pediatric cardiovascular surgical procedure patients undergoing delayed sternal closure

BACKGROUND

Many pediatric cardiac surgery centers obtain mediastinal cultures at the time of delayed sternal closure (DSC). There are no recommendations regarding how to treat patients with positive cultures. We explored the clinical significance of positive mediastinal cultures with regard to surgical site infections (SSI).

METHODS

A retrospective study was performed on all patients who underwent DSC at our institution between December 2006 and December 2011. National Healthcare Safety Network criteria were used to prospectively identify SSIs. Univariate and multivariate logistic regression analyses were performed to evaluate potential risk factors for SSI and predictors for positive mediastinal cultures obtained at DSC.

RESULTS

A total of 178 patients underwent DSC during the study period; 155 patients met the eligibility criteria for the study and were included in the analysis. Of the 155 included patients, 11 patients (7.1%) experienced SSI. Patients with a positive mediastinal culture obtained at DSC were more likely to experience SSI than were patients with a negative culture (p=0.003). In univariate analysis, a positive mediastinal culture was the only factor associated with SSI (odds ratio [OR], 7.4; 95% confidence interval [CI], 2.1 to 26.7). In multivariate analysis, age at operation≥2 weeks (adjusted OR [aOR], 4.9; 95% CI, 1.84 to 12.8), receipt of stress-dosed hydrocortisone while the chest was open (aOR, 2.9; 95% CI, 1.1 to 7.6), and gestational age≤37 weeks (aOR, 2.7; 95% CI, 1.01 to 7.27) were independent predictors for a positive mediastinal culture.

CONCLUSIONS

Patients with positive mediastinal cultures obtained at DSC had a significantly higher rate of subsequent SSI, and a positive mediastinal culture was the only statistically significant predictor of SSI.