Epidemiology and outcome of major postoperative infections following cardiac surgery: risk factors and impact of pathogen type

A nomogram predicting pneumonia after cardiac surgery: a retrospective modeling study

BACKGROUND

Postoperative pneumonia (POP) is the most prevalent of all nosocomial infections in patients who underwent cardiac surgery. The aim of this study was to identify independent risk factors for pneumonia after cardiac surgery, from which we constructed a nomogram for prediction.

METHODS

The clinical data of patients admitted to the Department of Cardiothoracic Surgery of Nanjing Drum Tower Hospital from October 2020 to September 2021 who underwent cardiac surgery were retrospectively analyzed, and the patients were divided into two groups according to whether they had POP: POP group (n=105) and non-POP group (n=1083). Preoperative, intraoperative, and postoperative indicators were collected and analyzed. Logistic regression was used to identify independent risk factors for POP in patients who underwent cardiac surgery. We constructed a nomogram based on these independent risk factors. Model discrimination was assessed via area under the receiver operating characteristic curve (AUC), and calibration was assessed via calibration plot.

RESULTS

A total of 105 events occurred in the 1188 cases. Age (>55 years) (OR: 1.83, P=0.0225), preoperative malnutrition (OR: 3.71, P<0.0001), diabetes mellitus(OR: 2.33, P=0.0036), CPB time (Cardiopulmonary Bypass Time) > 135 min (OR: 2.80, P<0.0001), moderate to severe ARDS (Acute Respiratory Distress Syndrome )(OR: 1.79, P=0.0148), use of ECMO or IABP or CRRT (ECMO: Extra Corporeal Membrane Oxygenation; IABP: Intra-Aortic Balloon Pump; CRRT: Continuous Renal Replacement Therapy )(OR: 2.60, P=0.0057) and MV( Mechanical Ventilation )> 20 hours (OR: 3.11, P<0.0001) were independent risk factors for POP. Based on those independent risk factors, we constructed a simple nomogram with an AUC of 0.82. Calibration plots showed good agreement between predicted probabilities and actual probabilities.

CONCLUSION

We constructed a facile nomogram for predicting pneumonia after cardiac surgery with good discrimination and calibration. The model has excellent clinical applicability and can be used to identify and adjust modifiable risk factors to reduce the incidence of POP as well as patient mortality.

Sepsis in cardiothoracic surgery

Sepsis is a life-changing condition that can occur in patients undergoing cardiothoracic surgery. It is characterized by a dysregulated inflammatory response to infection, often leading to higher rates of organ dysfunction and mortality. The importance of early recognition and prompt intervention in managing sepsis-related complications in cardiothoracic surgery is pivotal to adequate surgical practice. Due to the multiple subsections that construct the broad spectrum of cardiothoracic surgery, it is important to address the presence of sepsis in elective cardiothoracic surgery, urgent/emergency cardiothoracic surgery, solid organ transplantation, and both temporary and permanent mechanical circulatory support (ie, left ventricular assist devices, extracorporeal membrane oxygenation, and percutaneous temporary devices [eg, Impella series]). Exploring the incidence, prevalence, and risk factors of said subsections can lead to improvement in postoperative outcomes. The impact of accompanying infections can progress into further operative morbidity and mortality. To this effect, the perioperative management of cardiothoracic surgery transcends surgical techniques and should undergo additional recognition of other occurrences such as wound infections, bloodstream infections, urinary tract infections, and pneumonia. Sepsis remains a concern in cardiothoracic surgery, as it can lead to devastating consequences. Hence, there is an evident need for heightened vigilance, early recognition, and effective management strategies to mitigate the risk of sepsis in this patient population. The purpose of this article is to provide an overview of sepsis in the different cardiothoracic surgery areas.

Infectious complications following major heart surgery from the day of the surgery to hospital discharge

BACKGROUND

At some point in their lives, many people will require major heart surgery (MHS). Patients are generally older adults with various risk factors for infection. However, the incidence of infection after MHS is poorly known, as reported infection data are frequently biased due to different factors like the surgical procedure, postoperative timing, and infectious syndromes or etiologic agents, among others. In addition, most patient data are retrospectively obtained.

PURPOSE AND METHODS

Data were prospectively collected regarding the incidence of all nosocomial infections produced from the time of surgery to hospital discharge in a cohort of 800 adults consecutively undergoing a MHS procedure.

RESULTS

During postoperative hospitalization, 124 of the 800 participants developed one or more infections (15.5%): during their ICU stay in 68 patients (54.8%), during their stay on the general ward post ICU in 50 (40.3%), and during their stay in both wards in 6 (4.8%). The most common infections were pneumonia (related or not to mechanical ventilation), surgical site and bloodstream. As etiological agents, 193 pathogens were isolated: mostly Gram-negative bacilli (54.4%), followed by Gram-positive bacteria (30%), viruses (4.6%) and fungi (1.5%). In our cohort, all-cause mortality was recorded in 33 participants (4.1%) and 9 infection-related deaths (1.1%) were produced. Among subjects who developed infections, overall mortality was 13.7% and in those who did not, this was only 2.3%.

CONCLUSION

Infection following MHS remains frequent and severe. Our data suggest that hospital-acquired infection studies should consider episodes of infection in all populations during their entire hospital stay and not only those related to specific clinical syndromes or acquired while the patient is in intensive care.

Multidisciplinary Management of Sternal Osteomyelitis Due to Klebsiella aerogenes after Open Heart Surgery in a Patient with Multiple Myeloma: A Case Report and Discussion of the Literature

Sternal wound complications following cardiac surgery, including sternal dehiscence, mediastinitis, and osteomyelitis, pose significant challenges in terms of management and patient outcomes. We present a case report highlighting the complex management of a patient who underwent open heart surgery for severe aortic valve stenosis, followed by sternal wound dehiscence and sternum osteomyelitis due to extended spectrum beta lactamase (ESBL) producing Klebsiella aerogenes. A multiple myeloma diagnosis was also suspected at the positron emission tomography (PET) scan and confirmed with bone marrow biopsy. Multidisciplinary evaluation of the case led to a comprehensive treatment plan. To control the sternal osteomyelitis, total sternectomy was performed followed by immediate reconstruction with a bone (tibia) graft from the tissue bank and fixation with the minimal hardware possible. A microsurgical latissimus dorsi free flap was required to reconstruct the soft tissue defect. After 6 weeks of antibiotic treatment with ertapenem and fosfomycin based on a culture of intraoperative material, no clinical, imaging, or laboratory signs of infection were seen. Multiple myeloma treatment was then started. At 1 year of follow up, no recurrence of infection occurred, and the reconstruction was stable and closed. Multiple myeloma is under chronic treatment with novel agent combination, with an excellent haematological response.

The role of negative pressure wound therapy in the treatment of poststernotomy mediastinitis in Asians: A single-center, retrospective cohort study

Introduction

Poststernotomy mediastinitis (PSM) is a critical and life-threatening complication that can arise after cardiac surgery. The aim of this study was to evaluate and compare the outcomes of negative pressure wound therapy (NPWT) and conventional methods in the management of mediastinitis following heart surgery with a focus on Asian populations.

Methods

For this retrospective study, we included and evaluated a total of 34 patients who had undergone cardiac operations between January 2011 and September 2021 and developed PSM. The patients were divided into two groups, the NPWT group (n = 16, 47.1%) and the conventional treatment group (n = 18, 52.9%), and compared.

Results

The two groups showed no significant differences in terms of patient characteristics, PSM wound classification based on the El Oakley classification, and wound closure methods, but there was a higher incidence of diabetes mellitus in the NPWT group. With regard to mediastinal cultures, a higher prevalence of Staphylococcus epidermidis was observed in the NPWT group. However, we found no significant differences between the two groups regarding the time interval from diagnosis to wound closure, hospitalization duration, and re-exploration rate. Notably, the NPWT group exhibited a significantly higher in-hospital mortality rate than the conventional treatment group (p = 0.024).

Conclusions

Our findings suggest that the use of NPWT might not lead to improved medical outcomes for patients with PSM when compared to conventional treatment methods. As a result, it becomes imperative to exercise great care when choosing patients for NPWT. To obtain more definitive and conclusive results and identify the most appropriate cases for NPWT, conducting larger randomized clinical trials is necessary.

Diagnosis of Early Bacterial Pneumonia and Sepsis After Cardiovascular Surgery: A Diagnostic Prediction Model Based on LASSO Logistic Regression

Background

Early postoperative bacterial pneumonia and sepsis (ePOPS), which occurs within the first 48 hours after cardiovascular surgery, is a serious life-threatening complication. Diagnosis of ePOPS is extremely challenging, and the existing diagnostic tools are insufficient. The purpose of this study was to construct a novel diagnostic prediction model for ePOPS.

Methods

Least Absolute Shrinkage and Selection Operator (LASSO) with logistic regression was used to construct a model to diagnose ePOPS based on patients' comorbidities, medical history, and laboratory findings. The area under the receiver operating characteristic curve (AUC) was used to evaluate the model discrimination.

Results

A total of 1203 patients were recruited and randomly split into a training and validation set in a 7:3 ratio. By early morning on the 3rd postoperative day (POD3), 103 patients had experienced 133 episodes of bacterial pneumonia or sepsis (15 patients had both). LASSO logistic regression model showed that duration of mechanical ventilation (P=0.015), NYHA class ≥ III (P=0.001), diabetes (P<0.001), exudation on chest radiograph (P=0.011) and IL-6 on POD3 (P<0.001) were independent risk factors. Based on these factors, we created a nomogram named DICS-I with an AUC of 0.787 in the training set and 0.739 in the validation set.

Conclusion

The DICS-I model may be used to predict the risk of ePOPS after cardiovascular surgery, and is also especially suitable for predicting the risk of IRAO. The DICS-I model could help clinicians to adjust antibiotics on the POD3.

Incidence and predictors of sternal surgical wound infection in cardiac surgery: A prospective study

Sternal surgical wound infection (SSWI) in cardiac surgery is associated with increased morbidity. We investigated the incidence of SSWI, the main germs implicated and predictors of SSWI. Prospective study including patients undergoing full median sternotomy between January 2017 and December 2019. Patients were followed-up for 3 months after hospital discharge. All sternal wound infections up to 90 days after discharge were considered SSWI. 1004 patients were included. During follow-up, 68 (6.8%) patients presented SSWI. Patients with SSWI had a higher incidence of postoperative renal failure (29.4% vs 17.1%, P = .007), a higher incidence of early postoperative reoperation for non-infectious causes (42.6% vs 9.1%, P < .001), longer ICU stay (3 [2-9] days vs 2 [2-4] days, P = .006), and longer hospital stay (24.5 [14.8-38.3] days vs 10 [7-18] days, P < .001). Gram-positive germs were presented in 49% of the cultures, and gram-negative bacteria in 35%. Early reoperation for non-infectious causes (OR 4.90, 95% CI 1.03-23.7), and a longer ICU stay (OR 1.37 95% CI 1.10-1.72) were independent predictors of SSWI. SSWI is rare but leads to more postoperative complications. The need for early reoperation because of non-infectious cause and a longer ICU stay were independently associated with SSWI.

Nosocomial Extracardiac Infections After Cardiac Surgery

Purpose of Review

Nosocomial extracardiac infections after cardiac surgery are a major public health issue affecting 3–8.2% of patients within 30–60 days following the intervention.

Recent Findings

Here, we have considered the most important postoperative infective complications that, in order of frequency, are pneumonia, surgical site infection, urinary tract infection, and bloodstream infection. The overall picture that emerges shows that they cause a greater perioperative morbidity and mortality with a longer hospitalization time and excess costs. Preventive interventions and corrective measures, diminishing the burden of nosocomial extracardiac infections, may reduce the global costs. A multidisciplinary team may assure a more appropriate management of nosocomial extracardiac infections leading to a reduction of hospitalization time and mortality rate.

Summary

The main and most current data on epidemiology, prevention, microbiology, diagnosis, and management for each one of the most important postoperative infective complications are reported. The establishment of an antimicrobial stewardship in each hospital seems to be, at the moment, the more valid strategy to counteract the challenging problems.

Analysis of Risk Factors for Sternal Wound Infection After Off-Pump Coronary Artery Bypass Grafting

Objective

To investigate the risk factors of deep sternal wound infection (DSWI) after off-pump coronary artery bypass grafting and its prevention and treatment strategy.

Methods

The clinical data of 465 patients who underwent OPCABG with a median chest incision were retrospectively analyzed. The patients were divided into the observation group (with DSWI, 32 cases) and the control group (without DSWI, 433 cases) according to the occurrence of DSWI. The preoperative, intraoperative, and postoperative clinical data relevant to DSWI were collected in both groups. The univariate and multivariate logistic regression analyses were adopted to analyze the risk factors for DSWI after OPCABG and investigateand its prevention and treatment strategy.

Results

DSWI occurred in 32 cases with an incidence of infection of 6.89%. There were 5 cases died in the observation group (with DSWI), the overall mortality rate was 1.07% and the intra-group mortality rate was 15.6%. There were 16 cases died in the control group (without DSWI) because of low cardiac output syndrome and multiple organ failure, the overall and intra-group mortality rates were 3.44% and 3.69% respectively. By analyzing the risk factors of DSWI between the two groups, the differences in age, body mass index (BMI), history of diabetes mellitus (DM), operation time, tracheal intubation time, time of stay in thecardiac care unit, blood transfusion (blood plasma)>800mL, blood transfusion (erythrocyte suspension)>6um, secondary thoracotomy were statistically significant between the observation and control groups (P < 0.05 in all).

Conclusion

Obesity, history of DM, prolonged operation time and tracheal intubation time, time of stay in CCU, utilization of blood product and secondary thoracotomy were DSWI independent risk factors after OPCABG.Some preventive measure should been implemented to reduce the incidence of DSWI, such as shorter operation time and tracheal intubation time, reducing the utilization of blood product.

A bundle of infection control measures reduces post-operative sternal wound infection due to Staphylococcus aureus but not Gram-negative bacteria: a retrospective analysis of 6,903 patient episodes

BACKGROUND

Prevention of cardiac surgical site infection has largely focused on reducing infection due to Staphylococcus aureus although other bacteria also play an important role in this complication.

AIM

We assess the impact of an evolving infection control program on the incidence of sternal wound infection (SWI) and the changing incidence of non-staphylococcal infections.

METHODS

We conducted a retrospective cohort study of all patients who underwent primary sternotomy at a single UK centre between September 2010 and May 2018. Data were collated from two-years prior to the stepwise introduction of a broad-ranging infection control program, including S. aureus decolonisation.

FINDINGS

6,903 primary sternotomies were performed of which 2.6% (n=178) were complicated by SWI. Gram-negative bacteria (GNB) and S. aureus were most commonly identified as causative pathogens (45.5% and 30.3% respectively). Following program introduction there was a reduction in the rate of SWI from 3.9 to 1.8 cases/100 patients/month. This was mainly due to a sustained reduction in S. aureus infected cases with no discernible impact on GNB. Multivariable logistic regression analysis identified coronary artery bypass grafting, procedural urgency and procedures performed in the 3rd quarter as independent risk factors for post-operative infection.

CONCLUSION

A multifaceted infection control program was successful at reducing the rate of SWI primarily due to a reduction in S. aureus infections. GNB also play an important role in SWI and traditional preventative measures fail to address these. Future intervention and impact assessments should consider Gram negative infection when measuring effectiveness.

Gram-negative bacteria as a cause of mediastinitis after cardiac surgery

PURPOSE OF REVIEW

Poststernotomy mediastinitis (PSM) remains a serious infection and is significantly associated with high morbidity, short-term and long-term mortality. Gram-negative bacteria (GNB) are an underestimated cause of PSM, and there is little information on the risk factors, prevention, diagnosis and management of GNB PSM.

RECENT FINDINGS

The pathogenesis of PSM is the result of a complex and multifactorial interplay between intraoperative wound contamination, host-related and surgical host factors but GNB are probably mostly translocated from other host site infections. GNB are frequent cause of PSM (18-38% of cases) and GNB PSM have shown to more frequently polymicrobial (20-44%). GNG PSM has shown to occur earlier than Gram-positive PSM. Early diagnosis is crucial to successful treatment. The management of PSM needs a combination of culture-directed antimicrobial therapy and an early extensive surgical debridement with either immediate or delayed closure of the sternal space. Antibiotic treatment choice and duration should be based on clinical evaluation, evolution of inflammatory markers, microbiological tests and imaging studies. Mortality has shown to be significantly higher with GNB PSM compared with other causes and the inappropriateness of initial antibiotic therapy may explain the worse outcome of GNB PSM.

SUMMARY

GNB PSM is usually undervalued in the setting of PSM and have shown to be a frequent cause of inappropriate treatment with adverse prognostic potential. There is a need for efforts to improve knowledge to prevent and adequately treat GNB PSM.

Case-control study on the interplay between immunoparalysis and delirium after cardiac surgery

Background

Delirium occurs frequently following cardiothoracic surgery, and infectious disease is an important risk factor for delirium. Surgery and cardiopulmonary bypass induce suppression of the immune response known as immunoparalysis. We aimed to investigate whether delirious patients had more pronounced immunoparalysis following cardiothoracic surgery than patients without delirium, to explain this delirium-infection association.

Methods

A prospective matched case–control study was performed in two university hospitals. Cytokine production (tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-8 and IL-10) of ex vivo lipopolysaccharide (LPS)-stimulated whole blood was analyzed in on-pump cardiothoracic surgery patients preoperatively, and at 5 timepoints up to 3 days after cardiothoracic surgery. Delirium was assessed by trained staff using two validated delirium scales and chart review.

Results

A total of 89 patients were screened of whom 14 delirious and 52 non-delirious patients were included. Ex vivo-stimulated production of TNF-α, IL-6, IL-8, and IL-10 was severely suppressed following cardiothoracic surgery compared to pre-surgery. Postoperative release of cytokines in non-delirious patients was attenuated by 84% [IQR: 13–93] for TNF-α, 95% [IQR: 78–98] for IL-6, and 69% [IQR: 55–81] for IL-10. The attenuation in ex vivo-stimulated production of these cytokines was not significantly different in patients with delirium compared to non-delirious patients (p > 0.10 for all cytokines).

Conclusions

The post-operative attenuation of ex vivo-stimulated production of pro- and anti-inflammatory cytokines was comparable between patients that developed delirium and those who remained delirium-free after on-pump cardiothoracic surgery. This finding suggests that immunoparalysis is not more common in cardiothoracic surgery patients with delirium compared to those without.

The management of deep sternal wound infection: Literature review and reconstructive algorithm

Deep sternal wound infection (DSWI) is an important complication of open thoracic surgery, with a reported incidence of 0.5-6%. Given its association with increased morbidity, mortality, inpatient duration, financial burden, and re-operation rates, an aggressive approach to treatment is mandated. Flap reconstruction has become the standard of care, with studies demonstrating improved outcomes with reduced mortality and resource usage in patients undergoing early versus delayed flap reconstruction. Despite this, no evidence-based standard for the management of DSWI exists. We performed a thorough review of the literature to identify principles in management, using a PRISMA compliant methodology. Ovid-Embase, Medline and PubMed databases were searched for relevant papers using the search terms "deep sternal wound infection," and "post-sternotomy mediastinitis" to December 2019. Duplicates were removed, and the search narrowed to look at specific areas of interest i.e. negative pressure wound therapy, flap reconstruction, and rigid fixation. The reference list of included articles underwent full text review. No randomized controlled trials were identified. We review the current management techniques for patients with DSWI, and raise awareness for the need for further high quality studies, and a standardized national cardiothoracic-plastic surgery guideline to guide management. Based on our findings and the authors' own experience in this area, we provide evidence-based recommendations. We also propose a reconstructive algorithm.

Population pharmacokinetic evaluation of cefuroxime in perioperative antibiotic prophylaxis during and after cardiopulmonary bypass

AIMS

The purpose of this study was to explore pharmacokinetic and pharmacodynamic aspects of a contemporary dosing scheme of cefuroxime as perioperative prophylaxis in cardiac surgery using cardiopulmonary bypass (CPB).

METHODS

Cefuroxime plasma concentrations were measured in 23 patients. A 1.5-g dose of cefuroxime was administered at start of surgery and CPB, followed by 3 additional doses every 6 hours postoperative. Drug levels were used to build a population pharmacokinetic model. Target attainment for Staphylococcus aureus (2-8 mg/L) and Escherichia coli (8-32 mg/L) were evaluated and dosing strategies for optimization were investigated.

RESULTS

A dosing scheme of 1.5 g cefuroxime preoperatively with a repetition at start of CPB achieves plasma unbound concentrations of 8 mg/L in almost all patients during surgery. The second administration is critical to provide this level of coverage. Simulations indicate that higher unbound concentrations up to 32 mg/L are reached by a continuous infusion rate of 1 g/h after a bolus of 1 g. In the postoperative phase, most patients do not reach unbound concentrations above 2 mg/L. To improve target attainment up to 8 mg/L, the continuous application of cefuroxime with infusion rates of 0.125-0.25 g/h is simulated and shown to be an alternative to bolus dosing.

CONCLUSION

Dosing recommendations for cefuroxime as perioperative antibiotic prophylaxis in cardiac surgery are sufficient to reach plasma unbound concentration to cover S. aureus during the operation. Target attainment is not achieved in the postoperative period. Continuous infusion of cefuroxime may optimize target attainment.

Novel device prototyping for endoscopic cell sheet transplantation using a three-dimensional printed simulator

Introduction

Considering higher risks of candidates for cardiac regenerative therapy with compromised cardiac function, it is anticipated to develop less invasive surgical procedures. In the present study, we aimed to develop a prototype of totally endoscopic cell sheet delivery device and evaluate the surgical technique for epicardial cell sheet placement using three-dimensional (3D) printed simulators based on human computed tomography data.

Methods

We designed an endoscopic cell sheet delivery device with outer and inner frame with self-expandable applicator which can be opened in thoracic cavity. We launched spout line to provide liquids on the applicator surface and tension line to gently bend the applicator dorsally. We prepared human mesenchymal stem cell (MSC) sheets and compared wet/dry conditions of 3D printed heart/porcine heart and applicator to identify suitable conditions for cell sheet transplantation. Finally we validated the feasibility of endoscopic transplantation to anterior and lateral wall of left ventricle using 3D printed simulators.

Results

Moist condition of both 3D printed heart/porcine heart surface and applicator at transplantation yielded highest successful rate (100%, p = 0.0197). For both endoscopic transplantation sites, MSC sheets were successfully deployed. The procedure duration was 157 ± 23 s for anterior wall and 123 ± 13 s for the lateral wall in average, respectively.

Conclusions

We developed a novel prototype of endoscopic cell sheet delivery device for minimally-invasive cardiac regenerative therapy utilizing a 3D printed simulator. The commercialization of the prototype may provide a safe minimally-invasive method to deliver potential cardiac regenerative therapy in the future.

•

We invented a novel device for endoscopic cell sheet transplantation.

•

We optimized the transplantation procedure using three-dimensional printed simulator.

•

Commercialization of the device may provide standardized cardiac regenerative therapy.

Risk factors for surgical site infections using a data-driven approach

Objective

The objective of this study was to identify risk factors for surgical site infection from digestive, thoracic and orthopaedic system surgeries using clinical and data-driven cut-off values. A second objective was to compare the identified risk factors in this study to risk factors identified in literature.

Summary background data

Retrospective data of 3 250 surgical procedures performed in large tertiary care hospital in The Netherlands during January 2013 to June 2014 were used.

Methods

Potential risk factors were identified using a literature scan and univariate analysis. A multivariate forward-step logistic regression model was used to identify risk factors. Standard medical cut-off values were compared with cut-offs determined from the data.

Results

For digestive, orthopaedic and thoracic system surgical procedures, the risk factors identified were preoperative temperature of ≥38°C and antibiotics used at the time of surgery. C-reactive protein and the duration of the surgery were identified as a risk factors for digestive surgical procedures. Being an adult (age ≥18) was identified as a protective effect for thoracic surgical procedures. Data-driven cut-off values were identified for temperature, age and CRP which can explain the SSI outcome up to 19.5% better than generic cut-off values.

Conclusions

This study identified risk factors for digestive, orthopaedic and thoracic system surgical procedures and illustrated how data-driven cut-offs can add value in the process. Future studies should investigate if data-driven cut-offs can add value to explain the outcome being modelled and not solely rely on standard medical cut-off values to identify risk factors.

Hospital-acquired conditions occur more frequently in elective spine surgery than for other common elective surgical procedures

Hospital-acquired conditions (HACs) have been the focus of recent initiatives by the Centers for Medicare and Medicaid Services in an effort to improve patient safety and outcomes. Spine surgery can be complex and may carry significant comorbidity burden, including so called "never events." The objective was to determine the rates of common HACs that occur within 30-days post-operatively for elective spine surgeries and compare them to other common surgical procedures. Patients: >18 y/o undergoing elective spine surgery were identified in the American College of Surgeons' NSQIP database from 2005 to 2013. Patients were stratified by whether they experienced >1 HAC, then compared to those undergoing other procedures including bariatric surgery, THA and TKA. Of the 90,551 spine surgery patients, 3021 (3.3%) developed at least one HAC. SSI was the most common (1.4%), followed by UTI (1.3%), and VTE (0.8%). Rates of HACs in spine surgery were significantly higher than other elective procedures including bariatric surgery (2.8%) and THA (2.8%) (both p < 0.001). Spine surgery and TKA patients had similar rates of HACs(3.3% vs 3.4%, p = 0.287), though spine patients experienced higher rates of SSI (1.4%vs0.8%, p < 0.001) and UTI (1.3%vs1.1%, p < 0.001) but lower rates of VTE (0.8%vs1.6%, p < 0.001). Spine surgery patients had lower rates of HACs overall (3.3%vs5.9%) when compared to cardiothoracic surgery patients (p < 0.001). When compared to other surgery types, spine procedures were associated with higher HACs than bariatric surgery patients and knee and hip arthroplasties overall but lower HAC rates than patients undergoing cardiothoracic surgery.

Infections and outcomes after cardiac surgery-The impact of outbreaks traced to transesophageal echocardiography probes

Background

Infections are a frequent complication of cardiac surgery. The intraoperative use of transesophageal echocardiography (TEE) may be an underrecognized risk factor for post‐operative infections. The aim of this study was to investigate infection rates and outcomes after cardiac surgery in a nationwide cohort, especially in relation to periods where surface damaged TEE probes were used.

Methods

This was a retrospective, observational study at Landspitali University Hospital. All consecutive cardiac surgery patients from 1 January 2013 to 31 December 2017 were included. Patients’ charts were reviewed for evidence of infection, post‐operative complications or death.

Results

During the study period, 973 patients underwent cardiac surgery at Landspitali and 198 (20.3%) developed a post‐operative infection. The most common infections were: Pneumonia (9.1%), superficial surgical site (5.7%), bloodstream (2.8%) and deep sternal wound (1.7%). Risk factors for developing an infection included: The duration of procedure, age, insulin‐dependent diabetes, EuroScore II, reoperation for bleeding and an operation in a period with a surface damaged TEE probe in use. Twenty‐two patients were infected with a multidrug resistant strain of Klebsiella oxytoca, 10 patients with Pseudomonas aeruginosa and two patients developed endocarditis with Enterococcus faecalis. All three pathogens were cultured from the TEE probe in use at respective time, after decontamination. The 30‐day mortality rate in the patient cohort was 3.2%.

Conclusions

The intraoperative use of surface damaged TEE probes caused two serious infection outbreaks in patients after cardiac surgery. TEE probes need careful visual inspection during decontamination and probe sheaths are recommended.

A New Surgical Site Infection Risk Score: Infection Risk Index in Cardiac Surgery

Various scoring systems attempt to predict the risk of surgical site infection (SSI) after cardiac surgery, but their discrimination is limited. Our aim was to analyze all SSI risk factors in both coronary artery bypass graft (CABG) and valve replacement patients in order to create a new SSI risk score for such individuals. A priori prospective collected data on patients that underwent cardiac surgery (n = 2020) were analyzed following recommendations from the Reporting of studies Conducted using Observational Routinely collected health Data (RECORD) group. Study participants were divided into two periods: the training sample for defining the new tool (2010–2014, n = 1298), and the test sample for its validation (2015–2017, n = 722). In logistic regression, two preoperative variables were significantly associated with SSI (odds ratio (OR) and 95% confidence interval (CI)): diabetes, 3.3/2–5.7; and obesity, 4.5/2.2–9.3. The new score was constructed using a summation system for punctuation using integer numbers, that is, by assigning one point to the presence of either diabetes or obesity. The tool performed better in terms of assessing SSI risk in the test sample (area under the Receiver-Operating Characteristic curve (aROC) and 95% CI, 0.67/055–0.76) compared to the National Nosocomial Infections Surveillance (NNIS) risk index (0.61/0.50–0.71) and the Australian Clinical Risk Index (ACRI) (0.61/0.50–0.72). A new two-variable score to preoperative SSI risk stratification of cardiac surgery patients, named Infection Risk Index in Cardiac surgery (IRIC), which outperforms other classical scores, is now available to surgeons. Personalization of treatment for cardiac surgery patients is needed.

Current and emerging pharmacotherapy for the treatment of infections following open-heart surgery

INTRODUCTION

Patients undergoing open-heart surgery may suffer from postoperative complications, including severe infections. Antimicrobials to treat infectious complications in this population should be selected thoughtfully, taking into account three different and fundamental issues: (i) the site of infection; (ii) the suspected or proven causative agent and its susceptibility pattern; and (iii) the risk of suboptimal pharmacokinetic characteristics and potential toxicity of the chosen drug/s.

AREAS COVERED

The present narrative review summarizes the current and future antimicrobial options for the treatment of infections developing after open-heart surgery.

EXPERT OPINION

The pharmacological treatment of infections developing in cardiac surgery patients poses peculiar challenges, including the need for an active empirical therapy for severe events such as bloodstream infections, deep sternal wound infections, or early-onset postoperative prosthetic endocarditis. In addition, the risk for multidrug-resistant pathogens should also be taken into account in endemic areas. A multidisciplinary evaluation on a patient-by-patient basis, deeply involving infectious diseases specialists and cardiothoracic surgeons, remains essential for appropriately balancing both short-term and long-term risks and benefits of any possible surgical reintervention in combination with adequate pharmacotherapy.

Incidence and risk factors for potentially suboptimal serum concentrations of vancomycin during cardiac surgery

AIM

To investigate the incidence and risk factors for vancomycin concentrations less than 10 mg/L during cardiac surgery.

METHODS

In this prospective study, patients undergoing cardiac surgery received a single dose of 1000 mg of vancomycin. Multiple arterial samples were drawn during surgery. Exclusion criteria were hepatic dysfunction; renal dysfunction; ongoing infectious diseases; solid or hematologic tumors; severe insulin-dependent diabetes; body mass index of < 17 or > 40 kg/m²; pregnancy or lactation; antibiotic, corticosteroid, or other immunosuppressive therapy; vancomycin or nonsteroidal anti-inflammatory drug therapy in the previous 2 wk; chemotherapy or radiation therapy in the previous 6 mo; allergy to vancomycin or cefazolin; drug abuse; cardiac surgery in the previous 6 mo; previous or scheduled organ transplantation; preoperative stay in the intensive care unit for more than 24 h; emergency procedure or lack of adequate preparation for surgery; and participation in another trial.

RESULTS

Over a 1-year period, 236 patients were enrolled, and a total of 1682 serum vancomycin concentrations (median 7/patient) were measured. No vancomycin levels under 10 mg/L were recorded in 122 out of 236 patients (52%), and 114 out of 236 patients (48%) were found to have at least 1 serum sample with a vancomycin level < 10 mg/L; 54 out of 236 patients (22.9%) had at least 5 serum samples with a vancomycin level lower than 10 mg/L. Vancomycin infusion was administered for 60 min in 97 out of 236 patients (41%). In 47 patients (20%), the duration of infusion was longer than 60 min, and in 92 patients (39%) the duration of infusion was shorter than 60 min. The maximum concentration and area under the concentration-time curve were significantly higher in patients with no vancomycin levels less than 10 mg/L (P < 0.001). The multivariate analysis identified female gender, body mass index (BMI) > 25 kg/m², and creatinine clearance above 70 mL/min as risk factors for vancomycin levels less than 10 mg/L.

CONCLUSION

Results of this study identified female gender, BMI > 25 kg/m², and creatinine clearance above 70 mL/min as risk factors for suboptimal vancomycin serum concentration during cardiac surgery; no relationship was found between infusion duration and vancomycin levels less than 10 mg/L. These findings call attention to the risk of facilitating the emergence of vancomycin-resistant methicillin-resistant Staphylococcus aureus strains.

Current perspectives on diagnosis and management of sternal wound infections

Deep sternal wound infection (DSWI), also known as mediastinitis, is a serious and potentially fatal condition. The diagnosis and treatment of DSWI are challenging. In this current narrative review, the epidemiology, risk factors, diagnosis, and surgical and antimicrobial management of DSWI are discussed. Ideally, the management of DSWI requires early and sufficient surgical debridement and appropriate antibiotic therapy. When foreign material is present, biofilm-active antibiotic therapy is also needed. Because DSWI is often complex, the management requires the involvement of a multidisciplinary team consisting of cardiothoracic surgeons, plastic surgeons, intensivists, infectious disease specialists, and clinical microbiologists.

VIGILÂNCIA POR PISTAS OU RETROSPECTIVA? QUAL O IMPACTO NA NOTIFICAÇÃO DAS INFECÇÕES DO SÍTIO CIRÚRGICO EM CIRURGIA CARDÍACA

RESUMO Objetivo: avaliar o impacto das infecções do sítio cirúrgico notificadas pela vigilância por pistas comparadas àquelas detectadas pela avaliação retrospectiva do prontuário do paciente. Método: estudo epidemiológico e de reflexão conduzido em um hospital de grande porte, público, universitário. Resultados: a coleta dos dados ocorreu por meio de registros das notificações por pistas, realizada pela comissão de controle de infecção e por análise dos prontuários dos pacientes submetidos às cirurgias cardíacas entre os anos de 2011 e 2014. O diagnóstico da infecção do sítio cirúrgico seguiu os critérios definidos pelo National Healthcare Surveillance Network do Centers Disease Control. Os dados foram analisados no programa Epi-info® 6.4, por estatística descritiva. Foram analisados 294 pacientes submetidos a cirurgias cardíacas pela vigilância por pistas e 195 por revisão de prontuário. Notificaram-se 17 (65,9%) infecções do sítio cirúrgico superficiais; uma (3,8%) profunda; oito (30,8%) de órgão/cavidade na vigilância por pistas; 25 (69,4%) incisionais superficiais; dois (5,6%) profundas e nove (25%) de órgão/cavidade na revisão de prontuários. O impacto da vigilância por prontuários foi de 38,4% (36/26) em relação à vigilância por pistas. Conclusão: a vigilância por prontuários, apesar de sua reconhecida limitação, contribuiu, de forma importante, para se conhecer, de fato, as taxas de infecção do sítio cirúrgico. Sugere-se, aos serviços de investigação das infecções do sítio cirúrgico, repensar os métodos adotados para vigilância e, sobretudo, validar as taxas obtidas sob diferentes perspectivas que lhe sejam possíveis.

Deep sternal wound infection after cardiac surgery: a comparison of three different wound infection types and an analysis of antibiotic resistance

Background

Deep sternal wound infection (DSWI) is a severe complication following cardiac surgery. We compared epidemiology, clinical features, and microbiology of three types of DSWI and examined the antibiotic resistance in DSWI patients.

Methods

From 2011 to 2015, 170 adult post-cardiac surgery DSWI patients were recruited for this study and underwent the pectoralis major muscle flap transposition in our department.

Results

Of 170 adult patients with DSWI (mean age of 54 years), the majority (99 patients, 58.2%) had type II DSWI. The three types of DSWI patients showed significant differences in terms of gender, smoking history, chronic obstructive pulmonary disease (COPD), length of intensive care unit (ICU) stay, and hospitalization cost (P<0.05). The most common symptoms of DSWI patients were fever and wound dehiscence accompanied by purulent secretions. Types I and II DSWI were more frequently associated with hypoproteinemia and high leucocyte count (P<0.05). Microbiological diagnosis was available for 77 of 170 patients (45.3%). Of 157 pathogens detected, 87 (55.4%) species of gram negative bacilli were identified and most commonly were Pseudomonas aeruginosa (25.5%) and methicillin-susceptible Staphylococcus aureus (20.4%). However, no statistically significant microbiological differences among the three DSWI types were observed (P>0.05). Notably, P. aeruginosa isolates showed 100% resistance to cefazolin and cefuroxime. Meanwhile, the resistance rate of Acinetobacter baumannii isolates to commonly used antibiotics was greater than 70%, while resistance rates of staphylococcus to penicillin-G were 100% and to clindamycin were over 70%. No isolates were resistant to vancomycin, linezolid, and tigecycline.

Conclusions

Three types of DSWI exhibit differences in epidemiology and clinical features. P. aeruginosa and S. aureus are the most common pathogens in DSWI patients and antibiotic resistance is a serious concern in these patients. Therefore, prevention and treatment of DSWI should be closely tailored to clinical features, local microbiological characteristics, and resistance patterns of commonly encountered pathogens.

Incidence and outcomes of sepsis after cardiac surgery as defined by the Sepsis-3 guidelines

BACKGROUND

The Sepsis-3 guidelines diagnose sepsis based on organ dysfunction in patients with either proven or suspected infection. The objective of this study was to assess the incidence and outcomes of sepsis diagnosed using these guidelines in patients in a cardiac intensive care unit (CICU) after cardiac surgery.

METHODS

Daily sequential organ failure assessment (SOFA) scores were calculated for 2230 consecutive adult cardiac surgery patients between January 2013 and May 2015. Patients with an increase in SOFA score of ≥2 and suspected or proven infection were identified. The length of CICU stay, 30-day mortality and 2-yr survival were compared between groups. Multivariable linear regression, multivariable logistic regression, and Cox proportional hazards regression were used to adjust for possible confounders.

RESULTS

Sepsis with suspected or proven infection was diagnosed in 104 (4.7%) and 107 (4.8%) patients, respectively. After adjustment for confounding variables, sepsis with suspected infection was associated with an increased length of CICU stay of 134.1h (95% confidence interval (CI) 99.0-168.2, P<0.01) and increased 30-day mortality risk (odds ratio 3.7, 95% CI 1.1-10.2, P=0.02). Sepsis with proven infection was associated with an increased length of CICU stay of 266.1h (95% CI 231.6-300.7, P<0.01) and increased 30-day mortality risk (odds ratio 6.6, 95% CI 2.6-15.7, P<0.01).

CONCLUSIONS

Approximately half of sepsis diagnoses were based on proven infection and half on suspected infection. Patients diagnosed with sepsis using the Sepsis-3 guidelines have significantly worse outcomes after cardiac surgery. The Sepsis-3 guidelines are a potentially useful tool in the management of sepsis following cardiac surgery.

Operating Room Traffic as a Modifiable Risk Factor for Surgical Site Infection

BACKGROUND

Surgical site infections (SSI) contribute to surgical patients' morbidity and costs. Operating room traffic may be a modifiable risk factor for SSI. We investigated the impact of additional operating room personnel on the risk of superficial SSI (sSSI).

PATIENTS AND METHODS

In this matched case-control study, cases included patients in whom sSSI developed in clean surgical incisions after elective, daytime operations. Control subjects were matched by age, gender, and procedure. Operating room personnel were classified as (1) surgical scrubbed, (2) surgical non-scrubbed, or (3) anesthesia. We used conditional logistic regression to test the extent to which additional personnel overall and from each work group were associated with infection.

RESULTS

In total, 474 patients and 803 control subjects were identified. Each additional person among total personnel and personnel from each work group was significantly associated with greater odds of infection (all personnel, odds ratio [OR] = 1.082, 95% confidence interval [CI] 1.031-1.134, p = 0.0013; surgical scrubbed OR = 1.132, 95% CI 1.029-1.245, p = 0.0105; surgical non-scrubbed OR = 1.123, 95% CI 1.008-1.251, p = 0.0357; anesthesia OR = 1.153, 95% CI 1.031-1.290, p = 0.0127). After adjusting for operative duration, body mass index, diabetes mellitus, and vascular disease, additional personnel and sSSI were no longer associated overall or for any work groups (total personnel OR = 1.033, 95% CI 0.974-1.095, p = 0.2746; surgical scrubbed OR = 1.060, 95% CI 0.952-1.179, p = 0.2893; surgical non-scrubbed OR = 1.023 95% CI 0.907-1.154, p = 0.7129; anesthesia OR = 1.051, 95% CI 0.926-1.193, p = 0.4442).

CONCLUSION

The presence of additional operating room personnel was not independently associated with increased odds of sSSI. Efforts dedicated to sSSI reduction should focus on other modifiable risk factors.

Daptomycin for the treatment of major gram-positive infections after cardiac surgery

Background

Infection is a main cause of morbidity and mortality after heart surgery, with multi-resistant pathogens increasingly representing a challenge. Daptomycin provides bactericidal activity against gram-positive organisms that are resistant to standard treatment including vancomycin.

Methods

A cohort of cardiac surgical patients, treated with daptomycin for major infection at two tertiary care centers, were retrospectively studied with a particular focus on the type of infection, causative pathogens and co-infections, daptomycin dosage, adverse events and outcome in order to provide evidence for the efficiency and safety of daptomycin in a distinct high-risk patient population.

Results

Sixty-five patients (87.7 % males, 60.4 ± 13.5 years) who had undergone aortic surgery (20.0 %), ventricular assist device (VAD) implantation (21.5 %), combined procedures (21.5 %), coronary artery bypass grafting (12.3 %), isolated valve surgery (15.4 %) and heart transplantation (7.7 %) were diagnosed with catheter-related infection (26.1 %), valve endocarditis (18.8 %), sternal wound (13.0 %), VAD-associated (11.6 %), cardiac implantable electrophysiological device (CIED)-associated (4.1 %), respiratory tract (4.3 %), bloodstream (4.3 %) and other infection (4.3 %). In 13.0 %, no focus of infection was identified though symptoms of severe infection were present. The most frequent pathogens were Staphylococcus epidermidis (30.4 %), Staphylococcus aureus (23.1 %) and Enterococcus species (10.1 %). Daptomycin doses ranging from 3 mg/kg every 48 h to 10 mg/kg every 24 h were administered for 15.4 ± 11.8 days. 87.0 % of the cases were classified as success, 7.2 % as treatment failure and 5.8 as non-evaluable. Adverse events were limited to one case of mild and one case of moderate neutropenia with recovery upon termination of treatment.

Conclusion

Daptomycin proved safe and effective in major infection in high-risk cardiac surgical patients.

The human microbiota: novel targets for hospital-acquired infections and antibiotic resistance

PURPOSE

Hospital-acquired infections are increasing in frequency due to multidrug resistant organisms (MDROs), and the spread of MDROs has eroded our ability to treat infections. Health care professionals cannot rely solely on traditional infection control measures and antimicrobial stewardship to prevent MDRO transmission. We review research on the microbiota as a target for infection control interventions.

METHODS

We performed a literature review of key research findings related to the microbiota as a target for infection control interventions. These data are summarized and used to outline challenges, opportunities, and unanswered questions in the field.

RESULTS

The healthy microbiota provides protective functions including colonization resistance, which refers to the microbiota's ability to prevent colonization and/or expansion of pathogens. Antibiotic use and other exposures in hospitalized patients are associated with disruptions of the microbiota that may reduce colonization resistance and select for antibiotic resistance. Novel methods to exploit protective mechanisms provided by an intact microbiota may provide the key to preventing the spread of MDROs in the health care setting.

CONCLUSIONS

Research on the microbiota as a target for infection control has been limited. Epidemiologic studies will facilitate progress toward the goal of manipulating the microbiota for control of MDROs in the health care setting.

One Dose of Staphylococcus aureus 4C-Staph Vaccine Formulated with a Novel TLR7-Dependent Adjuvant Rapidly Protects Mice through Antibodies, Effector CD4+ T Cells, and IL-17A

A rapidly acting, single dose vaccine against Staphylococcus aureus would be highly beneficial for patients scheduled for major surgeries or in intensive care units. Here we show that one immunization with a multicomponent S. aureus candidate vaccine, 4C-Staph, formulated with a novel TLR7-dependent adjuvant, T7-alum, readily protected mice from death and from bacterial dissemination, both in kidney abscess and peritonitis models, outperforming alum-formulated vaccine. This increased efficacy was paralleled by higher vaccine-specific and α-hemolysin-neutralizing antibody titers and Th1/Th17 cell responses. Antibodies played a crucial protective role, as shown by the lack of protection of 4C-Staph/T7-alum vaccine in B-cell-deficient mice and by serum transfer experiments. Depletion of effector CD4⁺ T cells not only reduced survival but also increased S. aureus load in kidneys of mice immunized with 4C-Staph/T7-alum. The role of IL-17A in the control of bacterial dissemination in 4C-Staph/T7-alum vaccinated mice was indicated by in vivo neutralization experiments. We conclude that single dose 4C-Staph/T7-alum vaccine promptly and efficiently protected mice against S. aureus through the combined actions of antibodies, CD4⁺ effector T cells, and IL-17A. These data suggest that inclusion of an adjuvant that induces not only fast antibody responses but also IL-17-producing cell-mediated effector responses could efficaciously protect patients scheduled for major surgeries or in intensive care units.

Mortality among recipients of the Merck V710 Staphylococcus aureus vaccine after postoperative S. aureus infections: an analysis of possible contributing host factors

In a blinded randomized trial, preoperative receipt of the Merck V710 Staphylococcus aureus vaccine was associated with a higher mortality rate than placebo in patients who later developed postoperative S. aureus infections. Of the tested patients, all 12 V710 recipients (but only 1 of 13 placebo recipients) with undetectable serum IL2 levels prior to vaccination and surgery died after postoperative S. aureus infection. The coincidence of 3 factors (low prevaccination IL-2 levels, receipt of V710, and postoperative S. aureus infection) appeared to substantially increase mortality in our study population after major cardiothoracic surgery. Furthermore, 9 of the 10 V710 recipients with undetectable preoperative IL17a levels and postoperative S. aureus infections died. Although the current study is hypothesis-generating and the exact pathophysiology remains speculative, these findings raise concern that immune predispositions may adversely impact the safety and efficacy of staphylococcal vaccines actively under development. The potential benefits of an effective vaccine against S. aureus justify continued but cautious pursuit of this elusive goal.

Staphylococcus aureus Infections After Elective Cardiothoracic Surgery: Observations From an International Randomized Placebo-Controlled Trial of an Investigational S aureus Vaccine

BACKGROUND

An unmet need to prevent Staphylococcus aureus (SA) infections after cardiothoracic surgery persists despite current practices. Cost-effective implementation of preventive strategies requires contemporary knowledge about modifiable risk factors.

METHODS

From 2007 to 2011, an international, double-blind, randomized placebo-controlled trial of a novel SA vaccine (V710) was conducted in 7664 adults scheduled for median sternotomy at 164 sites. We analyzed SA infections developing up to 360 days postoperatively in 3832 placebo recipients.

RESULTS

Coronary artery bypass grafting was performed in 80.8% (3096 of 3832) of placebo recipients. The overall incidence of any postoperative SA infection was 3.1% (120 of 3832). Invasive SA infections (including bacteremia and deep sternal-wound infections) developed in 1.0%. Methicillin-resistant SA (MRSA) accounted for 19% (23 of 120) of SA infections, with 57% (13 of 23) of the MRSA infections occurring in diabetic patients. All-cause mortality was 4.1% (153 of 3712) in patients without SA infection, 7.2% (7 of 97) in methicillin-susceptible SA (MSSA) infections, and 17.3% (4 of 23) in MRSA infections (P < .01). Staphylococcus aureus nasal carriage was detected preoperatively in 18.3% (701 of 3096) patients, including 1.6% colonized with MRSA. Postoperative SA infections occurred in 7.0% (49 of 701) of colonized patients versus 2.3% (71 of 3131) of patients without colonization (relative risk = 3.1 [95% confidence interval, 2.2-4.4]).

CONCLUSIONS

In this large international cohort of patients undergoing cardiac surgery and observed prospectively, invasive postoperative SA infections occurred in 1% of adult patients despite modern perioperative management. The attributable mortality rates were 3% for MSSA and 13% for MRSA infections. Preoperative nasal colonization with SA increased the risk of postoperative infection threefold. The utility of strategies to reduce this incidence warrants continued investigation.

High-dose continuous oxacillin infusion results in achievement of pharmacokinetics targets in critically ill patients with deep sternal wound infections following cardiac surgery

Knowledge regarding antimicrobial therapy strategies in deep sternal wound infections (DSWI) following cardiac surgery is limited. Therefore, we aimed to determine the steady-state plasma and mediastinal concentrations of oxacillin administered by continuous infusion in critically ill patients with DSWI and to compare these concentrations with the susceptibility of staphylococci recovered. A continuous infusion of oxacillin (150 to 200 mg/kg of body weight/24 h) was administered after a loading dose (50 mg/kg). Plasma and mediastinal concentrations of total and unbound oxacillin were determined 4 h after the loading dose (H4) and then at day 1 (H24) and day 2 (H48). Twelve patients were included. Nine patients exhibited bacteremia, 5 were in septic shock, 8 were positive for Staphylococcus aureus, and 4 were positive for coagulase-negative staphylococci. The median MIC (first to third interquartile range) was 0.25 (0.24 to 0.41) mg/liter. Median plasma concentrations of total and unbound oxacillin at H4, H24, and H48 were, respectively, 64.4 (41.4 to 78.5) and 20.4 (12.4 to 30.4) mg/liter, 56.9 (31.4 to 80.6) and 21.7 (6.5 to 27.3) mg/liter, and 57.5 (32.2 to 85.1) and 20 (14.3 to 35.7) mg/liter. The median mediastinal concentrations of total and unbound oxacillin at H4, H24, and H48 were, respectively, 2.3 (0.7 to 25.9) and 0.9 (<0.5 to 15) mg/liter, 29.1 (19.7 to 38.2) and 12.6 (5.9 to 19.8) mg/liter, and 31.6 (14.9 to 42.9) and 17.1 (6.7 to 26.7) mg/liter. High-dose oxacillin delivered by continuous infusion is a valuable strategy to achieve our pharmacokinetic target (4× MIC) at the site of action at H24. But concerns remain in cases of higher MICs, emphasizing the need for clinicians to obtain the MICs for the bacteria and to monitor oxacillin concentrations, especially the unbound forms, at the target site.

Procalcitonin for the differential diagnosis of infectious and non-infectious systemic inflammatory response syndrome after cardiac surgery

Background

This study was performed to assess the value of procalcitonin (PCT) for the differential diagnosis between infectious and non-infectious systemic inflammatory response syndrome (SIRS) after cardiac surgery.

Methods

Patients diagnosed with SIRS after cardiac surgery between April 1, 2011 and March 31, 2013 were retrospectively studied. A total of 142 patients with SIRS, infectious (n = 47) or non-infectious (n = 95), were included. The patients with infectious SIRS included 11 with sepsis, 12 with severe sepsis without shock, and 24 with septic shock.

Results

PCT, C-reactive protein (CRP), and the white blood cell (WBC) count were significantly higher in the infectious SIRS group than in the non-infectious SIRS group. PCT had the highest sensitivity and specificity for differential diagnosis, with a cut-off value for infectious SIRS of 0.47 ng/mL. PCT was more reliable than CRP in diagnosing severe sepsis without shock, but it was not useful for diagnosing septic shock. The PCT cut-off value for diagnosing severe sepsis without shock was 2.28 ng/mL.

Conclusions

PCT was a useful marker for the diagnosis of infectious SIRS after cardiac surgery. The optimal PCT cut-off value for diagnosing infectious SIRS was 0.47 ng/mL.

Staphylococcus aureus and repeat bacteremia in febrile patients as early signs of sternal wound infection after cardiac surgery

BACKGROUND

Sternal wound infection is a devastating complication of cardiothoracic surgery that carries high postoperative morbidity and mortality rates. We explored whether our current program of extensive bacteriological examination including repeat blood cultures may contribute to the early diagnosis of sternal wound infection.

METHODS

We retrospectively analyzed 112 patients who were subjected to our bacteriological examination protocol including within 90 days after cardiothoracic surgery. Univariate and multivariate analyses were made in order to identify risk factors for sternal infection.

RESULTS

The median patient age was 75 years, and 65 patients were male. In 35 cases (31.2%) the blood cultures showed the presence of bacterial infection with the following frequencies: Staphylococcus aureus, 18 cases; Coagulase-negative Staphylococcus, 7 cases; other organisms, 10 cases. Eleven patients presented repeat bacteremia on at least 2 different occasions. Twenty patients (17.8%) presented sternal wound infections. There was no difference in operative mortality between the patients with and without sternal wound infection. Univariate and multivariate analyses demonstrated that bilateral mammary artery use (OR, 13.68, 95% CI, 1.09-167.36, p = 0.043), positive blood culture for Staphylococcus aureus (OR, 19.51, 95% CI, 4.46-104.33, p < 0.0001), repeat bacteremia (OR, 17.98, 95% CI, 2.51-161.77, p = 0.004) were risk factors that were associated for sternal wound infection.

CONCLUSION

Repeat blood cultures in febrile patients appear to be useful for the early detection of Staphylococcus aureus and repeat bacteremia, and these were associated with sternal wound infection. Bilateral internal mammary artery use was another risk factor of sternal wound infection in febrile patients. These factors may identify patients suitable for expeditious radiological examination and aggressive treatments.