The impact of nosocomial infections on patient outcomes following cardiac surgery

Effect of single-patient room design on the incidence of nosocomial infection in the intensive care unit: a systematic review and meta-analysis

Background

Previous studies have yielded varying conclusions regarding the impact of single-patient room design on nosocomial infection in the intensive care unit (ICU). We aimed to examine the impact of ICU single-patient room design on infection control.

Methods

We conducted a comprehensive search of PubMed, Embase, the Cochrane Library, Web of Science, CNKI, WanFang Data, and CBM databases from inception to October 2023, without language restrictions. We included observational cohort and quasi-experimental studies assessing the effect of single- versus multi-patient rooms on infection control in the ICU. Outcomes measured included the nosocomial infection rate, incidence density of nosocomial infection, nosocomial colonization and infection rate, acquisition rate of multidrug-resistant organisms (MDROs), and nosocomial bacteremia rate. The choice of effect model was determined by heterogeneity.

Results

Our final analysis incorporated 12 studies involving 12,719 patients. Compared with multi-patient rooms in the ICU, single-patient rooms demonstrated a significant benefit in reducing the nosocomial infection rate (odds ratio [OR]: 0.68; 95% confidence interval [CI]: 0.59, 0.79; p < 0.00001). Analysis based on nosocomial infection incidence density revealed a statistically significant reduction in single-patient rooms (OR: 0.64; 95% CI: 0.44, 0.92; p = 0.02). Single-patient rooms were associated with a marked decrease in nosocomial colonization and infection rate (OR: 0.44; 95% CI: 0.32, 0.62; p < 0.00001). Furthermore, patients in single-patient rooms experienced lower nosocomial bacteremia rate (OR: 0.73; 95% CI: 0.59, 0.89; p = 0.002) and lower acquisition rate of MDROs (OR: 0.41; 95% CI: 0.23, 0.73; p = 0.002) than those in multi-patient rooms.

Conclusion

Implementation of single-patient rooms represents an effective strategy for reducing nosocomial infections in the ICU.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/).

Utility of heparin-binding protein following cardiothoracic surgery using cardiopulmonary bypass

Cardiothoracic surgery using cardiopulmonary bypass (CPB) triggers an inflammatory state that may be difficult to differentiate from infection. Heparin-binding protein (HBP) is a candidate biomarker for sepsis. As data indicates that HBP normalizes rapidly after cardiothoracic surgery, it may be a suitable early marker of postoperative infection. We therefore aimed to investigate which variables influence postoperative HBP levels and whether elevated HBP concentration is associated with poor surgical outcome. This exploratory, prospective, observational study enrolled 1475 patients undergoing cardiothoracic surgery using CPB, where HBP was measured at ICU arrival. Patients with HBP in the highest tercile were compared to remaining patients. Multivariable logistic regressions were performed to identify factors predictive of elevated HBP and 30-day mortality. Overall median HBP was 30.0 ng/mL. Patients undergoing isolated CABG or surgery with CPB-duration ≤ 60 min had a median HBP of 24.9 ng/mL and 23.2 ng/mL, respectively. Independent predictors of elevated postoperative HBP included increased EuroSCORE, prolonged CPB-duration and high intraoperative temperature. Increased HBP was an independent predictor of 30-day mortality. This study confirms the promising characteristics of HBP as a biomarker for identification of postoperative sepsis, especially after routine procedures. Further studies are required to investigate whether HBP may detect postoperative infections.

Clinical, Microbiological and Treatment Characteristics of Severe Postoperative Respiratory Infections: An Observational Cohort Study

Respiratory infections are frequent and life-threatening complications of surgery. This study aimed to evaluate the clinical, microbiological and treatment characteristics of severe postoperative pneumonia (POP) and tracheobronchitis (POT) in a large series of patients. This single-center, prospective observational cohort study included patients with POP or POT requiring intensive care unit admission in the past 10 years. We recorded demographic, clinical, microbiological and therapeutic data. A total of 207 patients were included, and 152 (73%) were men. The mean (SD) age was 70 (13) years and the mean (SD) ARISCAT score was 46 (19). Ventilator-associated pneumonia was reported in 21 patients (10%), hospital-acquired pneumonia was reported in 132 (64%) and tracheobronchitis was reported in 54 (26%). The mean (SD) number of days from surgery to POP/POT diagnosis was 6 (4). The mean (SD) SOFA score was 5 (3). Respiratory microbiological sampling was performed in 201 patients (97%). A total of 177 organisms were cultured in 130 (63%) patients, with a high proportion of Gram-negative and multi-drug resistant (MDR) bacteria (20%). The most common empirical antibiotic therapy was a triple-drug regimen covering MDR Gram-negative bacteria and MRSA. In conclusion, surgical patients are a high-risk population with a high proportion of early onset severe POP/POT and nosocomial bacteria isolation.

A fatal Candida albicans pericarditis presenting with cardiac tamponade after COVID-19 infection and cardiothoracic surgery

BACKGROUND

Candida pericardial infection is a rare clinical entity usually related to recent cardiothoracic surgery and chronic debilitating conditions. During the COVID-19 pandemic, invasive fungal infections have been on the rise, likely due to a combination of factors such as immunosuppression, underlying conditions like diabetes, and surgical procedures.

CASE PRESENTATION

Herein, we report a 67-year-old diabetic woman with a history of COVID-19 infection who received a high dose of corticosteroids a few months before admission, and previous myocardial infarction for more than 12 years. The patient had a positive cardiac tamponade with signs of dyspnea, chest pain, and low blood pressure. Echocardiographic data were more in favor of constrictive pericarditis. The patient underwent urgent echocardiography-guided pericardiocentesis and then broad-spectrum antibiotic treatment was prescribed. Repeated echocardiography implied a persistent pericardial effusion 10 days later. Subxiphoid aspirates and biopsied tissues showed budding yeast cells and yeast colonies grew on culture media identified as Candida albicans.

CONCLUSION

This report should bring to the attention of physicians toward the possibility of Candida pericardial infection presenting with cardiac tamponade after COVID-19 infection and cardiothoracic surgery. Echocardiographic assessment, prompt pericardiotomy, molecular-based identification of causative agent, and early administration of appropriate antifungal treatment should improve the patient's survival.

Impact of preheart transplant spirometry and DCLO measurement on post-transplant pulmonary outcomes

BACKGROUND

Pulmonary function tests (PFT) are a frequent component of heart transplant evaluation. In cardiac surgery abnormal PFTs, especially reduced DLCO, have been associated with poor outcomes. We sought to evaluate the impact of pretransplant PFTs on post-transplant pulmonary outcomes and patient survival.

METHODS

Among the 652 adult heart transplant recipients between January 1, 2010 and July 31, 2021, 462 had PFTs and constituted the patient cohort. Obstructive ventilatory defects (OVD), restrictive ventilatory defects (RVD), and reduced DLCO were defined according to established criteria. The primary outcome was the combined endpoint of a post-transplant pulmonary complication defined as reintubation, postoperative pneumonia, prolonged intubation, or tracheostomy. Secondary outcomes included 90-day all-cause mortality, length of stay, and the odds of individual pulmonary complications. Kaplan-Meier survival analysis, multivariable Cox proportional-hazards regression, and multivariable logistic regression were performed to compare outcomes between the groups.

RESULTS

Patients with severe OVD (OR 1.48, 95% CI 1.18-5.23, p = 0.02) or severely reduced DLCO (OR 1.95, 95% CI 1.19-3.20, p = 0.008) had increased odds of post-transplant pulmonary complications. Following multivariable adjustment, severe OVD (aOR 2.67, 95% CI 1.15-6.19, p = 0.02) and severely reduced DLCO (aOR 1.79, 95% CI 1.05-3.04) remained strongly associated with post-transplant pulmonary complications. Patients with any degree of extrinsic RVD, moderate or less OVD, or moderately reduced DLCO or less did not have increased odds of post-transplant pulmonary complications. Ninety-day post-transplant survival was significantly reduced for both severe OVD (97.2% vs 86.5%, p = 0.04) and severely reduced DLCO (97.3% vs 90.4%, p = 0.004). Post-transplant ICU and hospital length of stay were nominally longer for both groups as well.

CONCLUSIONS

Severe OVD or severely reduced DLCO on preheart transplant PFTs were associated with increased odds of post-transplant pulmonary complications and early mortality.

Radionuclide Imaging of Infective Endocarditis

Infective endocarditis (IE) is associated with high morbidity and mortality. Early diagnosis is crucial for adequate patient management. Due to difficulties in the diagnosis, a multidisciplinary discussion in addition to the integration of clinical signs, microbiology data, and imaging data is used. Imaging, including echocardiography, molecular imaging techniques, and coronary CT angiography (CTA) is central to detect infections involving heart valves and implanted cardiovascular devices, also allowing for early detection of septic emboli and metastatic. This article describes the main clinical application of white blood cell SPECT/CT and [¹⁸F]FDG-PET/CT and CTA in IE and infections associated with cardiovascular implantable electronic devices.

Efficacy of maintaining low-tidal volume mechanical ventilation as compared to resting lung strategy during coronary artery bypass graft cardiopulmonary bypass surgery: A post-hoc analysis of the MECANO trial

STUDY OBJECTIVE

To compare a low-tidal-volume with positive end-expiratory pressure strategy (VENT strategy) to a resting-lung-strategy (i.e., no-ventilation (noV) strategy) during cardiopulmonary bypass for coronary artery bypass graft surgery on the incidence of postoperative pulmonary complications.

DESIGN

Post-hoc analysis of the MECANO trial which was a prospective single-center, blind, randomized, parallel-group controlled trial.

SETTING

Tertiary care cardiac surgery center.

PATIENTS

Patients who underwent isolated on-pump coronary bypass surgery were randomized either to VENT or noV group.

INTERVENTION

During the cardiopulmonary bypass phase of the cardiac surgery procedure, mechanical ventilation in the VENT group consisted of a tidal volume of 3 mL/kg, a respiratory rate of 5 per minute and a positive end-expiratory pressure of 5 cmH₂O. Patients in the noV group received no ventilation during this phase.

MEASUREMENTS

Primary composite outcome combining death, early respiratory failure, ventilation support beyond day 2 and reintubation.

MAIN RESULTS

In this post-hoc analysis, we retained 725 patients who underwent isolated CABG surgery, from the 1501 patients included in the original study. There were 352 in the VENT group and 373 patients in the noV group. Post-hoc comparison yielded no differences in baseline characteristics between these two groups. The primary outcome occurred less frequently in the VENT group than in the noV group, with 44 (12.5%) and 76 (20.4%) respectively (odds-ratio (OR) = 0.56 (0.37-0.84), p = 0.004). There were fewer early respiratory dysfunctions and prolonged respiratory support in the VENT group (respectively, OR = 0.34 (0.12-0.96) p = 0.033 and OR = 0.51 (0.27-0.94) p = 0.029). Complications related to mechanical ventilation were similar in the two groups.

CONCLUSIONS

In this post-hoc analysis, maintaining low-tidal ventilation compared to a resting-lung strategy was associated with fewer pulmonary postoperative complications in patients who underwent isolated CABG procedures.

MONOCYTIC MYELOID-DERIVED SUPPRESSOR CELL EXPANSION AFTER CARDIAC SURGERY WITH CARDIOPULMONARY BYPASS INDUCES LYMPHOCYTE DYSFUNCTION

ABSTRACT

Cardiac surgery with cardiopulmonary bypass (CPB) is associated with an immune paresis that predisposes to the development of postoperative infections and sepsis. Among factors responsible for CPB-induced immunosuppression, circulating myeloid-derived suppressor cells (MDSCs) have been found to induce early lymphocyte apoptosis and lymphocyte proliferation inhibition. However, the mechanisms involved are not fully understood. In this study, we found that the main lymphocyte subsets decreased significantly 24 h after cardiac surgery with CBP. As expected, cardiac surgery with CPB induced a monocytic MDSC expansion associated with an increased T-cell apoptosis and decreased proliferation capacity. Noteworthy, granulocytic MDSCs remain stable. Myeloid-derived suppressor cell depletion restored the ability of T-cell to proliferate ex vivo . After CPB, indoleamine 2,3-dioxygenase activity and IL-10 plasma level were increased such as programmed death-ligand 1 monocytic expression, whereas plasma level of arginine significantly decreased. Neither the inhibition of indoleamine 2,3-dioxygenase activity nor the use of anti-programmed death-ligand 1 or anti-IL-10 blocking antibody restored the ability of T-cell to proliferate ex vivo . Only arginine supplementation restored partially the ability of T-cell to proliferate.

Evaluation of the significance of interleukin-6 in the diagnosis of postoperative pneumonia: a prospective study

Background

Postoperative pneumonia (PP) is one of the most common complications after cardiac surgery. This study was designed to access the diagnostic value of interleukin-6 (IL-6) for pneumonia within the first 5 days after cardiac surgery in adults.

Method

This prospective observational study enrolled 694 patients who admitted to our center from 10 October 2020 to 30 June 2021. Blood samples were collected after admission and on five consecutive days after surgery to measure IL-6, procalcitonin (PCT), C-reactive protein (CRP) and white blood cells (WBC) respectively. Combined with clinical data, we assessed the diagnostic performance of different biomarkers using univariate and multifactorial analyses as well as receiver operating characteristic curves (ROC) and the area under the curve (AUC).

Result

Finally, 68 patients were diagnosed with PP (PP Group). In addition, 626 cases were assigned to the control group (Non-PP Group). From postoperative day 1 (POD1) to day 5, IL-6 and PCT levels showed higher diagnostic value (P < 0.001, P < 0.05, respectively); meanwhile, there was no difference in white blood cell counts between the two groups; CRP showed some value from POD2 onwards (P < 0.001). Among these biomarkers, IL-6 on POD1 [AUC: 0.78, 95% confidence interval (CI): 0.71–0.83], IL-6 on POD2 (AUC: 0.77, 95% CI: 0.71–0.82) and CRP levels on POD3 (AUC: 0.77, 95% CI: 0.70–0.84) had the highest diagnostic value. Multivariate analysis found that smoking status [odds ratio(OR): 7.79, 95% CI: 3.05, 19.88, p < 0.001], drinking status (OR: 22.68, 95% CI: 9.29, 55.37, p < 0.001) and hypertension (OR: 2.85, 95% CI: 1.28, 6.35, p = 0.011), IL-6 on POD2 (OR: 1.01, 95% CI: 1.00, 1.01, p = 0.018), mechanical ventilation time (OR: 1.03, 95% CI: 1.00, 1.05, p = 0.040) and intensive care unit stay time (OR: 1.01, 95% CI: 1.00, 1.02, p < 0.001) were independent risk factors for postoperative pneumonia.

Conclusion

Smoking, drinking, hypertension, prolonged duration of mechanical ventilation and intensive care unit stay, and IL-6 on POD2 were independent risk factors for pneumonia after cardiovascular surgery. IL-6 level on POD2 may serve as a promising indicator, better than WBC, PCT and CRP.

Establishment and Validation of a Nomogram to Predict Hospital-Acquired Infection in Elderly Patients After Cardiac Surgery

Background

Hospital-acquired infection (HAI) after cardiac surgery is a common clinical concern associated with adverse prognosis and mortality. The objective of this study is to determine the prevalence of HAI and its associated risk factors in elderly patients following cardiac surgery and to build a nomogram as a predictive model.

Methods

We developed and internally validated a predictive model from a retrospective cohort of 6405 patients aged ≥70 years, who were admitted to our hospital and underwent cardiac surgery. The primary outcome was HAI. Multivariable logistic regression analysis was used to identify independent factors significantly associated with HAI. The performance of the established nomogram was assessed by calibration, discrimination, and clinical utility. Internal validation was achieved by bootstrap sampling with 1000 repetitions to reduce the overfit bias.

Results

Independent factors derived from the multivariable analysis to predict HAI were smoking, myocardial infarction, cardiopulmonary bypass use, intraoperative erythrocytes transfusion, extended preoperative hospitalization days and prolonged duration of mechanical ventilation postoperatively. The derivation model showed good discrimination, with a C-index of 0.706 [95% confidence interval 0.671–0.740], and good calibration [Hosmer–Lemeshow test P = 0.139]. Internal validation also maintained optimal discrimination and calibration. The decision curve analysis revealed that the nomogram was clinically useful.

Conclusions

We developed a predictive nomogram for postoperative HAIs based on routinely available data. This predictive tool may enable clinicians to achieve better perioperative management for elderly patients undergoing cardiac surgery but still requires further external validation.

Characterisation of Plasma Mitochondrial DNA, MMP-9 and Neutrophil Elastase in Patients Undergoing Coronary Artery Bypass Grafting: Effects of Tranexamic Acid and Postoperative Pneumonia

BACKGROUND

Postoperative pneumonia is a major cause of morbidity and mortality following cardiac surgery. The inflammatory response to cardiac surgery has been widely studied, but specific mechanisms for postoperative pneumonia have not been determined. Tranexamic acid is renowned for its effect on bleeding but can also modulate inflammatory processes. Cardiac surgery is known to release mitochondrial DAMPs (mtDAMPs) and is linked to postoperative inflammation and atrial fibrillation. We speculated that mtDAMPs might be related to postoperative pneumonia and that this might be modulated by tranexamic acid.

METHODS

Forty-one (41) patients from the Aspirin and Tranexamic Acid for Coronary Artery Surgery (ATACAS) trial were studied. Levels of mitochondrial DNA, matrix metallopeptidase 9 (MMP-9) and neutrophil elastase (NE) were determined in plasma preoperatively, at 24 and 72 hours post-surgery and correlated with clinical outcome.

RESULTS

mtDNA was significantly elevated postoperatively in the placebo and tranexamic acid (TXA) groups. Neutrophil elastase increased immediately postoperatively and at 24 hours. MMP-9 was elevated in the placebo group early postoperatively and in the TXA group at the immediate postoperative time point and after 24 hours. Six (6) of the 41 (14.6%) patients subsequently developed pneumonia. mtDNA levels were significantly increased at the early postoperative period and the 24-hour time point in patients with pneumonia.

CONCLUSIONS

Cardiac surgery releases mtDNA, increases MMP-9 and NE and this was not influenced by TXA. Inflammation postoperatively might be linked to pneumonia since mtDNA was further elevated in these patients. Due to the low number of individuals developing pneumonia, further studies are warranted to clearly identify whether TXA impacts on the inflammatory response in postoperative pneumonia.

Diagnosis of infection after cardiovascular surgery (DICS): a study protocol for developing and validating a prediction model in prospective observational study

INTRODUCTION

Postoperative infection (PI) is one of the main severe complications after cardiovascular surgery. Therefore, antibiotics are routinely used during the first 48 hours after cardiovascular surgery. However, there is no effective method for early diagnosis of infection after cardiovascular surgery, particularly, to determine whether postoperative patients need to prolong the use of antibiotics after the first 48 hours. In this study, we aim to develop and validate a diagnostic model to help identify whether a patient has been infected after surgery and guide the appropriate use of antibiotics.

METHODS AND ANALYSIS

In this prospective study, we will develop and validate a diagnostic model to determine whether the patient has a bacterial infection within 48 hours after cardiovascular surgery. Baseline data will be collected through the electronic medical record system. A total of 2700 participants will be recruited (n=2000 for development, n=700 for validation). The primary outcome of the study is the newly PI during the first 48 hours after cardiovascular surgery. Logistic regression penalised with elastic net regularisation will be used for model development and bootstrap and k-fold cross-validation aggregation will be performed for internal validation. The derived model will be also externally validated in patients who are continuously included in another time period (N=700). We will evaluate the calibration and differentiation performance of the model by Hosmer-Lemeshow good of fit test and the area under the curve, respectively. We will report sensitivity, specificity, positive predictive value and negative predictive value in the validation data-set, with a target of 80% sensitivity.

ETHICS AND DISSEMINATION

Ethical approval was obtained from Medical Ethics Committee of Affiliated Nanjing Drum Tower Hospital, Nanjing University Medical College (2020-249-01).

TRIAL REGISTRATION NUMBER

Chinese Clinical Trial Register (www.chictr.org.cn, ChiCTR2000038762); Pre-results.

Methicillin-Resistant Staphylococcus aureus (MRSA): Prevalence, Antimicrobial Susceptibility Pattern, and Detection of mecA Gene among Cardiac Patients from a Tertiary Care Heart Center in Kathmandu, Nepal

Background:

Methicillin Resistant Staphylococcus aureus (MRSA) is a significant human pathogen associated with nosocomial infections. mecA in the S. aureus is a marker of MRSA. The main objective of this study was to detect mecA and vanA genes conferring resistance in S. aureus among cardiac patients attending Sahid Gangalal National Heart Centre (SGNHC), Kathmandu, Nepal between May and November 2019.

Methods:

A total of 524 clinical samples (blood, urine, sputum) were collected and processed. Bacterial isolates were tested for antimicrobial susceptibility test (AST) and screening for MRSA was carried out by cefoxitin disc diffusion method. Minimum inhibitory concentration (MIC) of vancomycin for MRSA was established by agar dilution method and chromosomal DNA was extracted and used in polymerase chain reaction targeting the mecA and vanA genes.

Results:

Out of 524 specimens, 27.5% (144/524) showed bacterial growth. Among 144 culture positive isolates, S. aureus (27.1%; 39/144) was the predominant bacteria. Among 39 S. aureus isolates, all isolates were found resistant to penicillin followed by erythromycin (94.9%; 37/39), gentamicin (94.9%; 37/39) and cefoxitin (87.2%; 34/39). Out of 39 S. aureus, 87.2% (34/39) were MRSA. Among 34 MRSA, 8.8% (3/34) were vancomycin intermediate S. aureus (VISA). None of the MRSA was resistant to vancomycin. All of the 3 VISA isolates were obtained from inpatients. Of 39 S. aureus, 82.1% (32/39) harbored mecA gene. Similarly, the entire VISA isolates and 94.1% (32/34) of the MRSA isolates were tested positive for mecA gene.

Conclusions:

High prevalence of MRSA among the cardiac patients indicates the increasing burden of drug resistance among bacterial isolates. Since infection control is the crucial step in coping with the burgeoning antimicrobial resistance in the country, augmentation of diagnostic facilities with routine monitoring of drug resistance is recommended.

Impact of healthcare-associated infection on length of stay

BACKGROUND

Increased length of stay (LOS) for patients is an important measure of the burden of healthcare-associated infection (HAI).

AIM

To estimate the excess LOS attributable to HAI.

METHODS

This was a one-year prospective incidence study of HAI observed in one teaching hospital and one general hospital in NHS Scotland as part of the Evaluation of Cost of Nosocomial Infection (ECONI) study. All adult inpatients with an overnight stay were included. HAI was diagnosed using European Centres for Disease Prevention and Control definitions. A multi-state model was used to account for the time-varying nature of HAI and the competing risks of death and discharge.

FINDINGS

The excess LOS attributable to HAI was 7.8 days (95% confidence interval (CI): 5.7-9.9). Median LOS for HAI patients was 30 days and for non-HAI patients was 3 days. Using a simple comparison of duration of hospital stay for HAI cases and non-cases would overestimate the excess LOS by 3.5 times (27 days compared with 7.8 days). The greatest impact on LOS was due to pneumonia (16.3 days; 95% CI: 7.5-25.2), bloodstream infections (11.4 days; 5.8-17.0) and surgical site infection (SSI) (9.8 days; 4.5-15.0). It is estimated that 58,000 bed-days are occupied due to HAI annually.

CONCLUSION

A reduction of 10% in HAI incidence could make 5800 bed-days available. These could be used to treat 1706 elective patients in Scotland annually and help reduce the number of patients awaiting planned treatment. This study has important implications for investment decisions in infection prevention and control interventions locally, nationally, and internationally.

Nosocomial Infection

OBJECTIVE

The first 70 years of critical care can be considered a period of "industrial revolution-like" advancement in terms of progressing the understanding and care of critical illness. Unfortunately, like the industrial revolution's impact on the environment, advancing ICU care of increasingly elderly, immunosuppressed, and debilitated individuals has resulted in a greater overall burden and complexity of nosocomial infections within modern ICUs. Given the rapid evolution of nosocomial infections, the authors provide an updated review.

DATA SOURCES AND STUDY SELECTION

We searched PubMed and OVID for peer-reviewed literature dealing with nosocomial infections in the critically ill, as well as the websites of government agencies involved with the reporting and prevention of nosocomial infections. Search terms included nosocomial infection, antibiotic resistance, microbiome, antibiotics, and intensive care.

DATA EXTRACTION AND DATA SYNTHESIS

Nosocomial infections in the ICU setting are evolving in multiple domains including etiologic pathogens plus novel or emerging pathogens, prevalence, host risk factors, antimicrobial resistance, interactions of the host microbiome with nosocomial infection occurrence, and understanding of pathogenesis and prevention strategies. Increasing virulence and antimicrobial resistance of nosocomial infections mandate increasing efforts toward their prevention.

CONCLUSIONS

Nosocomial infections are an important determinant of outcome for patients in the ICU setting. Systematic research aimed at improving the prevention and treatment of nosocomial infections is still needed.

Early infections after successful transcatheter aortic valve replacement are associated with increased short- and long-term mortality: A single-center study

BACKGROUND

We reviewed frequency, microbiological pattern, predictors, and outcomes of early infections following transcatheter aortic valve replacement (TAVR).

METHODS

Five hundred thirty-nine patients who underwent successful TAVR at a single, high-volume center between January 2014 and December 2019 were enrolled. We defined early infections as occurring within 30-day from TAVR.

RESULTS

Mean age was 83.5 ± 5.4 years; 230 (42.7%) patients were men. Median follow-up was 12.0 (5.7-18.3) months; 30-day and 1-year death rates were 8/539 (1.5%) and 30/539 (5.6%), respectively. Early infections occurred in 61/539 (11.3%) patients, of whom 2 had infections in two sites. Of the 63 infections, 10 were bloodstream infections (BSI), 5 urinary tract, 27 pulmonary (2 with sepsis), 6 access site infections, 1 enterocolitis, and 14 were clinically diagnosed (no specific site). We observed 31/63 (49.2%) microbiologically-documented infections: Gram+ bacteria were isolated in 12/31 (38.7%), Gram- in 17/31 (54.3%), both Gram+ and Gram- in 2/31 (6.5%); in thirty-two infections no specific pathogen could be isolated (clinically-documented infections). Early infections were more prevalent in patients who died within 30-day (8.2% vs. 0.6%, p < 0.001) or 1-year (14.8% vs. 4.4%, p < 0.001) from TAVR. At multivariable analysis, early infections were independently associated with 30-day (HR: 8.82, 95% CI: 1.11-19.83, p = 0.035) and 1-year mortality (HR: 2.10, 95%CI: 1.28-6.21, p = 0.041). The predictive value for 1-year mortality was maintained even restricting the analysis to documented infections only, or to more severe infections (BSI and pneumonia only) (all p < 0.05).

CONCLUSIONS

Early infections occur in 1/10th of TAVR and are associated with increased short- and long-term mortality. Whereas a causal relationship between early infections and the risk of death cannot be unequivocally proven, careful surveillance of infected patients may improve TAVR results.

A systems approach to examine hospital-acquired infections in a paediatric CICU

OBJECTIVE

We aimed to apply systems engineering principles to address hospital-acquired infections in the paediatric intensive care setting.

DESIGN

Mixed method approach involving four steps: perform time-motion study of cardiac intensive care unit (CICU) care processes, establish a meaningful schema to classify observations, design a web-based system to manage and analyse data, and design a prototypical computer-based training system to assist with hygiene compliance.

SETTING

Paediatric CICU at the Children's Healthcare of Atlanta.

PATIENTS

Paediatric patients undergoing congenital heart surgery.

INTERVENTIONS

Extensive time-motion study of CICU care processes.

MEASUREMENTS

Non-compliances were recorded for each care process observed during the time-motion study.

RESULTS

Guided by our observations, we introduced a novel categorisation schema with action types, observation categories, severity classes, procedure classifications, and personnel categories that offer a systematic and efficient mechanism for reporting and classifying non-compliance and violations. Utilising these categories, a web-based database management system was designed that allows observers to input their data. This web analytic tool offers easy summarisation, data analysis, and visualisation of findings. A computer-based training system with modules to educate visitors in hospital-acquired infections hygiene was also created.

CONCLUSION

Our study offers a checklist of non-compliance situations and potential development of a proactive surveillance system of awareness of infection-prone situations. Working with quality improvement experts and stakeholders, recommendations and actionable practice will be synthesised for implementation in clinical settings. Careful design of the implementation protocol is needed to measure and quantify the potential improvements in outcomes.

The Dynamics of Heparin-Binding Protein in Cardiothoracic Surgery-A Pilot Study

OBJECTIVES

To explore the preoperative, intraoperative, and postoperative dynamics of heparin-binding protein (HBP) in cardiothoracic surgery.

DESIGN

This was a prospective, observational study.

SETTING

The study was conducted at a single university hospital.

PARTICIPANTS

Thirty patients undergoing cardiac surgery with cardiopulmonary bypass (CPB) were included, 15 of whom underwent coronary artery bypass grafting surgery and 15 of whom underwent complex procedures. Ten patients undergoing lung surgery also were included as a conventional surgery reference group.

INTERVENTIONS

No interventions were performed.

MEASUREMENTS AND MAIN RESULTS

HBP was measured at nine different perioperative times. HBP levels increased immediately after heparin administration, further increased during CPB, but decreased rapidly after protamine administration. At arrival to the intensive care unit, median HBP levels were 24.8 (15.6-38.1) ng/mL for coronary artery bypass grafting patients and 51.2 (34.0-117.7) ng/mL for complex surgery patients (p = 0.011). One day after surgery, HBP levels in all three groups were below the proposed cutoff of 30 ng/mL, which previously was found to predict development of organ dysfunction in patients with infection.

CONCLUSIONS

HBP levels are elevated by the administration of heparin and the use of CPB but reduced by protamine administration. At postoperative day one, HBP levels were less than the threshold for organ dysfunction in patients with infection. The usefulness of HBP for predicting postoperative infections in cardiothoracic surgery should be investigated in future studies.

Perioperative outcomes of coronary artery bypass graft surgery in Johannesburg, South Africa

Background

The perioperative complications in patients with coronary artery disease undergoing coronary artery bypass graft (CABG) surgery have been reported predominantly from developed countries, with a paucity of data from sub-Saharan Africa. We aim to report on the clinical characteristics and perioperative complications in patients with obstructive coronary artery disease, managed with CABG surgery at a tertiary academic hospital in Johannesburg, South Africa.

Methods

We retrospectively reviewed data from adult patients who underwent CABG surgery during a 17-year period (January 2000 – December 2017). Data was collected from the cardiothoracic surgery department’s pre- and postoperative reports, the cardiology department’s medical records, and anaesthesiology’s intra-operative reports. We collected demographic, biochemical, clinical, surgical, echocardiographic, and angiographic data. Outcomes data collected included perioperative complications and mortality.

Results

We analysed 1218 consecutive patient records. The study cohort consisted of 951 (78.1%) males, and the mean age was 60.1 ± 10.1 years. During the study period, 137 (11.2%) patients demised with cardiac and sepsis-related causes of death accounting for 49.6 and 37.2%, respectively. Other perioperative complications included excessive bleeding in 222 (18.2%), prolonged ventilation (exceeding 48 h) in 139 (11.4%), and sternal sepsis in 125 (10.3%). On univariate logistic regression analysis, advanced age, a lower left ventricular ejection fraction, smoking, increased cardiopulmonary bypass (CPB) time, and a higher European System for Cardiac Operative Risk Evaluation (EuroSCORE) II were all significantly associated with mortality. The EuroSCORE II [OR: 0.15 95%CI: 0.09–0.22; p = 0.000], and prolonged CPB time [OR: 0.01 CI: 0.00–0.02; p = 0.000] were independent predictors of in-hospital all-cause mortality.

Conclusions

In our study, the crude perioperative mortality rate was 11.2%. Our mortality rate was significantly higher than the mortality rates reported in other developed and developing countries. To better understand the factors driving this high mortality rate, a prospective outcomes registry has been initiated, and this promises to inform on our contemporary mortality and morbidity outcomes.

Pulmonary Complications of Cardiac Surgery

Cardiothoracic surgery posits an arrangement of large, significant hemodynamic, and physiologic alterations upon the human body, which predisposes a patient to develop pathology. The care of these patients in the postoperative realm requires an astute physician with deep understanding of the cardiopulmonary system, who is able to address subtle developing problems promptly, before the patient suffers further sequelae. In this review, we describe the presentation and management of an assortment of important complications which occur in the pulmonary system. In addition, we aim to shed better light upon how the physiology of a patient responds to the condition of cardiothoracic surgery.

Impact of nosocomial infections on patient mortality following cardiac surgery

STUDY OBJECTIVE

To determine the rate of nosocomial infection among patients undergoing cardiac surgery and to identify risk factors and the impact of these infections on patient mortality.

DESIGN

Prospective observational study.

SETTING

Intensive Care Unit (ICU).

PATIENTS

1097 adult patients who underwent cardiac surgery at Hospital Clínico Universitario de Valladolid between January 2011 and January 2016.

INTERVENTIONS

None.

MEASUREMENTS

Preoperative, intraoperative and postoperative medical, surgical and anaesthetic variables.

MAIN RESULTS

A total of 111 patients (10.1%) acquired a nosocomial infection in the postoperative period. Pneumonia was the most frequent (4.2%) nosocomial infection. Three independent risk factors for the development of a nosocomial infection were identified: cardiopulmonary bypass time, kidney failure and emergency surgery. The stay in the ICU was significantly higher in patients who developed a nosocomial infection (16.6 ± 38.8 vs. 4.4 ± 17.8, P < 0.001). The mortality rate of patients who acquired a nosocomial infection was significantly greater (18%) than that of patients who did not acquire a nosocomial infection (5%) (P < 0.001). The 90-day survival was greater in the group of patients without nosocomial infection (log rank 27.55, P < 0.001). The dynamic modelling of 90-day mortality revealed that in the first week, cardiopulmonary bypass time (HR = 1.00, 95% CI 1.00-1.02, P < 0.001) and emergency surgery (HR = 0.12, 95% CI 0.04-0.37, P < 0.001) were the most important risk factors for mortality, while after the first week, nosocomial infection (HR = 6.23, 95% CI 2.49-15.63, P < 0.001) was the main risk factor, followed by cardiopulmonary bypass time (HR = 1.01, 95% CI 1.00-1.01, P = 0.001) and EuroSCORE (HR = 1.03, 95% CI 1.00-1.06, P = 0.008).

CONCLUSIONS

Nosocomial infections after cardiac surgery constitute the main independent risk factor for mortality after the first week of surgery. These data suggest that its prevention following cardiac surgery must be prioritised to improve patient outcomes.

Low Tidal Volume Mechanical Ventilation Against No Ventilation During Cardiopulmonary Bypass in Heart Surgery (MECANO): A Randomized Controlled Trial

BACKGROUND

Postoperative pulmonary complications are common after cardiac surgery and have been related to lung collapse during cardiopulmonary bypass (CPB). No consensus exists regarding the effects of maintaining mechanical ventilation during CPB to decrease these complications.

RESEARCH QUESTION

To determine whether maintaining low-tidal ventilation (3 mL/kg 5 times/min, with positive end expiratory pressure of 5 cm H₂O) during CPB (ventilation strategy) was superior to a resting-lung strategy with no ventilation (no ventilation strategy) regarding postoperative pulmonary complications, including mortality.

STUDY DESIGN AND METHODS

In a randomized controlled trial, patients undergoing cardiac surgery at a single center from May 2017 through August 2019 were randomized to the ventilation or no ventilation strategy during CPB (1:1 ratio). Apart from the CPB phase, perioperative ventilation procedures were standardized.

RESULTS

The study included 1,501 patients (mean age, 68.8 ± 10.3 years; 1,152 (76.7%) men; mean EuroSCORE II, 2.3 ± 2.7). Seven hundred fifty-six patients were in the ventilation strategy group, and no differences existed in baseline characteristics and types of procedures between the two groups. An intention-to-treat analysis yielded no significant difference between the ventilation and no ventilation groups regarding incidence of the primary composite outcome combining death, early respiratory failure, ventilation support beyond day 2, and reintubation, with 112 of 756 patients (14.8%) in the ventilation group vs 133 of 745 patients (17.9%) in the no ventilation group (OR, 0.80; 95% CI, 0.61-1.05; P = .11). Strict per-protocol analyses of 1,338 patients (89.1%) with equally distributed preoperative characteristics yielded similar results (OR, 0.81; 95% CI, 0.60-1.09; P = .16). Post hoc analysis of the subgroup who underwent isolated coronary artery bypass graft procedures (n = 725) showed that the ventilation strategy was superior to the no ventilation strategy regarding the primary outcome (OR, 0.56; 95% CI, 0.37-0.84; P = .005).

INTERPRETATION

Among patients undergoing cardiac surgery with CPB, continuation of low tidal volume ventilation was not superior to no ventilation during CPB with respect to postoperative complications, including death, early respiratory failure, ventilation support beyond day 2, and reintubation.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT03098524; URL: www.clinicaltrials.gov.

Postoperative Pneumonia Following Open Heart Surgery

Objectives

This study aimed to measure the incidence and record the relations between risk factors of postoperative pneumonia (POP) among patients who underwent open heart surgery in a single hospital in Saudi Arabia. 

Methods

This retrospective cohort study was conducted in June 2019 at King Abdulaziz University hospital in Saudi Arabia. Data including general information, comorbidities, lab investigations, preoperative risk factors, intraoperative considerations, and postoperative elements were collected and analyzed.

Results

A total of 255 cardiac surgeries were performed from November 2014 to June 2019. Two hundred of the 255 cardiac surgeries were analyzed as open-heart surgeries. Only five patients were diagnosed with POP after open heart surgery with an incidence of 2.5%. The mean age of these patients was 47±18 years, more than half of them were smokers, three were hypertensive, four were classified as ASA 4, and three underwent the operation electively. The mean bypass time was 100.3 ± 24.5 min, the mean duration of operation was 199 ± 86.2 min, the mean postoperative intensive care unit (ICU) stay was 97.4 ± 83.4 hours, and the mean overall hospital stay was 10.4 ± 7.2 days. We observed significant differences in only the following correlations: amount of blood transfusion with ICU stay and with the overall hospital stay.

Conclusion

The incidence of developing postoperative pneumonia in patients undergoing open heart surgery in the King Abdulaziz University hospital from November 2014 to June 2019 was 2.5%, indicating a high-quality level of surgical technique and proper infection control.

Mortality due to hospital-acquired infection after cardiac surgery

PURPOSE

Hospital-acquired infections have been associated with significant morbidity and mortality in critically ill surgical patients. However, little is known about mortality due to hospital-acquired infections in cardiac surgery.

METHODS

We conducted a retrospective analysis of prospectively collected data from the cardiac surgery unit of a university hospital. All patients who underwent cardiac surgery over a 7-year period were included. Patients with hospital-acquired infections were matched 1:1 with patients with nonhospital-acquired infections based on risk factors for hospital-acquired infections and death after cardiac surgery using propensity score matching. We performed a competitive risk analysis to study the mortality fraction due to hospital-acquired infections.

RESULTS

Of 8853 patients who underwent cardiac surgery, 370 (4.2%) developed 500 postoperative infections (incidence density rate 4.2 hospital-acquired infections per 1000 patient-days). Crude hospital mortality was significantly higher in patients with hospital-acquired infections than in matched patients who did not develop hospital-acquired infections, 15.4% and 5.7%, respectively (P < .001). The in-hospital mortality fraction due to hospital-acquired infections in our cohort was 17.1% (12.3%-22.8%). Pseudomonas aeruginosa infection (hazard ratio, 2.09; 95% confidence interval, 1.23-3.49; P = .005), bloodstream infection (hazard ratio, 2.08; 95% confidence interval, 1.19-3.63; P = .010), and pneumonia (hazard ratio, 1.68; 95% confidence interval, 1.02-2.77; P = .04) were each independently associated with increased hospital mortality.

CONCLUSIONS

Although hospital-acquired infections are relatively uncommon after cardiac surgery (4.2%), these infections have a major impact on postoperative mortality (attributable mortality fraction, 17.1%).

Risk Factors for Candidemia After Open Heart Surgery: Results From a Multicenter Case-Control Study

BACKGROUND

Candida species are among the most frequent causative agents of health care-associated bloodstream infections, with mortality >40% in critically ill patients. Specific populations of critically ill patients may present peculiar risk factors related to their reason for intensive care unit admission. The primary objective of the present study was to assess the predictors of candidemia after open heart surgery.

METHODS

This retrospective, matched case-control study was conducted in 8 Italian hospitals from 2009 to 2016. The primary study objective was to assess factors associated with the development of candidemia after open heart surgery.

RESULTS

Overall, 222 patients (74 cases and 148 controls) were included in the study. Candidemia developed at a median time (interquartile range) of 23 (14-36) days after surgery. In multivariable analysis, independent predictors of candidemia were New York Heart Association class III or IV (odds ratio [OR], 23.81; 95% CI, 5.73-98.95; P < .001), previous therapy with carbapenems (OR, 8.87; 95% CI, 2.57-30.67; P = .001), and previous therapy with fluoroquinolones (OR, 5.73; 95% CI, 1.61-20.41; P = .007). Crude 30-day mortality of candidemia was 53% (39/74). Septic shock was independently associated with mortality in the multivariable model (OR, 5.64; 95% CI, 1.91-16.63; P = .002). No association between prolonged cardiopulmonary bypass time and candidemia was observed in this study.

CONCLUSIONS

Previous broad-spectrum antibiotic therapy and high NYHA class were independent predictors of candidemia in cardiac surgery patients with prolonged postoperative intensive care unit stay.

Seasonality of postoperative pneumonia after coronary artery bypass grafting: A national inpatient sample study

BACKGROUND

The development of postoperative pneumonia following cardiac surgery is associated with significant morbidity and mortality. However, seasonal variation as a risk factor for the development of postoperative pneumonia remains to be investigated. We sought to investigate whether patients undergoing coronary artery bypass grafting (CABG) during "flu season" (Fall and Winter months) at increased risk of postoperative pneumonia.

MATERIALS AND METHODS

A retrospective cohort study of patients undergoing CABG in the National Inpatient Sample between 2005 and 2015 was completed. Concomitant diagnosis of pneumonia was defined as the primary outcome. Secondary outcomes were defined to include pneumonia secondary to several known pathogens. Outcomes with significant differences between Fall/Winter and Spring/Summer groups were further analyzed with additive time series decomposition. Odds ratios were generated and adjusted for age, sex, elective status, and 29 other Agency for Healthcare Research and Quality comorbidity measures.

RESULTS

A total of 238 757 and 277 941 patients undergoing CABG during Fall/Winter and Spring/Summer, respectively, were identified. A significantly increased risk of postoperative pneumonia (adjusted odds ratio [aOR] = 1.15) and infection with influenza (aOR = 4.08), Haemophilus influenzae (aOR = 1.40), and Streptococcus pneumoniae (aOR = 1.47) was observed among patients receiving CABG in Q1 (January-March) compared to Q3 (July-September).

CONCLUSIONS

There is a strong seasonality in the incidence of postoperative pneumonia after CABG which may persist across other cardiothoracic surgeries. In addition to optimizing infection control and perioperative care, cardiac surgeons should consider preoperative vaccination against seasonal influenza, H. influenzae, and S. pneumoniae to improve outcomes among high-risk patients.

Risk factors of nosocomial infection after cardiac surgery in children with congenital heart disease

Background

The aim of our study was to analyze the risk factors of nosocomial infection after cardiac surgery in children with congenital heart disease (CHD).

Methods

We performed a retrospective cohort study, and children with CHD who underwent open-heart surgeries at Shanghai Children’s Medical Center from January 1, 2012 to December 31, 2018 were included. The baseline characteristics of these patients of different ages, including neonates (0–1 months old), infants (1–12 months old) and children (1–10 years old), were analyzed, and the association of risk factors with postoperative nosocomial infection were assessed.

Results

A total of 11,651 subjects were included in the study. The overall nosocomial infection rate was 10.8%. Nosocomial infection rates in neonates, infants, and children with congenital heart disease were 32.9, 15.4, and 5.2%, respectively. Multivariate logistic regression analysis found age (OR 0798, 95%CI: 0.769–0.829; P < 0.001), STS risk grade (OR 1.267, 95%CI: 1.159–1.385; P < 0.001), body mass index (BMI) <5th percentile (OR 1.295, 95%CI: 1.023–1.639; P = 0.032), BMI >95th percentile (OR 0.792, 95%CI: 0.647–0.969; P = 0.023), cardiopulmonary bypass (CPB) time (OR 1.008, 95%CI: 1.003–1.012; P < 0.001) and aortic clamping time (OR 1.009, 1.002–1.015; P = 0.008) were significantly associated with nosocomial infection in CHD infants. After adjusted for confounding factors, we found STS risk grade (OR 1.38, 95%CI: 1.167–1.633; P < 0.001), BMI < 5th percentile (OR 1.934, 95%CI: 1.377–2.715; P < 0.001), CPB time (OR 1.018, 95%CI: 1.015–1.022; P < 0.001), lymphocyte/WBC ratio<cut off value (OR 3.818, 95%CI: 1.529–9.533; P = 0.004) and AST>cut off value (OR 1.546, 95%CI: 1.119–2.136; P = 0.008) were significantly associated with nosocomial infection in CHD children.

Conclusion

Our study suggested STS risk grade, BMI, CPB duration, low lymphocyte/WBC or high neutrophil/WBC ratio were independently associated with nosocomial infection in CHD infant and children after cardiac surgery.

Effects of perioperative transcutaneous electrical acupoint stimulation on monocytic HLA-DR expression in patients undergoing coronary artery bypass grafting with cardiopulmonary bypass: study protocol for a double-blind randomized controlled trial

BACKGROUND

Cardiac surgery involving cardiopulmonary bypass (CPB) is known to be associated with a transient postoperative immunosuppression. When severe and persistent, this immune dysfunction predisposes patients to infectious complications, which contributes to a prolonged stay in the intensive care unit (ICU), and even mortality. Effective prevention and treatment methods are still lacking. Recent studies revealed that acupuncture-related techniques, such as electroacupuncture and transcutaneous electrical acupoint stimulation (TEAS), are able to produce effective cardioprotection and immunomodulation in adult and pediatric patients undergoing cardiac surgery with CPB, which leads to enhanced recovery. However, whether perioperative application of TEAS, a non-invasive technique, is able to improve immunosuppression of the patients with post-cardiosurgical conditions is unknown. Thus, as a preliminary study, the main objective is to evaluate the effects of TEAS on the postoperative expression of monocytic human leukocyte antigen (-D related) (mHLA-DR), a standardized "global" biomarker of injury or sepsis-associated immunosuppression, in patients receiving on-pump coronary artery bypass grafting (CABG).

METHODS

This study is a single-center clinical trial. The 88 patients scheduled to receive CABG under CPB will be randomized into two groups: the group receiving TEAS, and the group receiving transcutaneous acupoint pseudo-electric stimulation (Sham TEAS). Expression of mHLA-DR serves as a primary endpoint, and other laboratory parameters (e.g., interleukin [IL]-6, IL-10) and clinical outcomes (e.g., postoperative infectious complications, ICU stay time, and mortality) as the secondary endpoints. In addition, immune indicators, such as high mobility group box 1 protein and regulatory T cells will also be measured.

DISCUSSION

The current study is a preliminary monocentric clinical trial with a non-clinical primary endpoint, expression of mHLA-DR, aiming at determining whether perioperative application of TEAS has a potential to reverse CABG-associated immunosuppression. Although the immediate clinical impact of this study is limited, its results would inform further large-sample clinical trials using relevant patient-centered clinical outcomes as primary endpoints.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02933996. Registered on 13 October 2016.

Negative-pressure sternal wound closure with interrupted subcuticular suturing and a subcutaneous drain tube reduces the incidence of poststernotomy wound infection after coronary artery bypass grafting surgery

PURPOSES

To retrospectively evaluate the effect of negative-pressure sternal wound closure (NPSWC) with a subcutaneous closed drain tube on the sternal surgical site infection (SSI) incidence.

METHODS

After propensity score matching of 231 patients undergoing coronary artery bypass grafting (CABG), we compared 104 pairs in the NPSWC and historical control groups. In the molecular analysis, the interleukin-6 (IL-6), basic fibroblast growth factor (b-FGF), and transforming growth factor β1 (TGF-β1) levels in the wound fluid were measured using two different reservoir types at postoperative days 2 and 7.

RESULTS

NPSWC significantly reduced the SSI incidence from 10.6 to 2.9%. No mediastinitis occurred in the NPSWC group. A multivariate logistic regression analysis identified female sex (p = 0.0040) and no NPSWC (p = 0.0084) as significant risk factors for sternal SSI development. The Negative-pressure value was 49.4 ± 4.1 and 115.5 ± 15.2 mmHg in the standard-type (SSR) and bulb-type suction reservoirs (BSR), respectively. Given that growth factors were affected by the difference in negative pressure, the IL-6, b-FGF, and TGF-β1 levels were significantly higher in the BSR than in the SSR.

CONCLUSIONS

NPSWC using a subcutaneous closed drain tube was effective in preventing sternal SSI after CABG and may accelerate wound healing even when both internal thoracic arteries are harvested.

CLINICAL REGISTRATION NUMBER

University Hospital Medical Information Network Clinical Trials Registry, registration number: UMIN000037060.

Epidemiology and outcome of Klebsiella pneumoniae carbapenemase-producing Klebsiella pneumoniae (KPC-KP) infections in cardiac surgery patients: a brief narrative review

Klebsiella pneumoniae carbapenemase-producing Klebsiella pneumoniae (KPC-KP) is a difficult-to-treat pathogen due to its multidrug-resistant phenotype. Cardiac surgery patients are at increased risk of developing KPC-KP infections compared to other populations, with previous KPC-KP colonization being a critical factor in influencing the risk of subsequent infection. Two different pieces of information are essential to comprehensively assess the local characteristics of KPC-KP colonization in cardiac surgery patients: (i) the local prevalence of colonization; (ii) the timing of colonization. Treatment of KPC-KP infections in cardiac surgery patients is a complex task, but more effective treatment options have recently become available. Nonetheless, implementation and full adherence to infection-control measures remain of pivotal importance for reducing the burden of KPC-KP infections in this peculiar population. The aim of this narrative review is to summarize the available literature on the epidemiology and outcome of KPC-KP infections in cardiac surgery patients.

Changes of the Serum Antibiotic Levels During Open Heart Surgery (ceftazidim, ciprofloxacin, clindamycin)

Background: Wound, mediastinal and intracardiac infections are still very serious complications of open-heart surgey. The incidence of it is still in the range of 0.4%-5%. The aims of our study were to assess the adequacy of regimen using ceftazidim (CTZ), ciprofloxacin (CPF) and clindamycin (CLIN) as prophylactic antibiotics and to verify whether cardiopulmonary bypass (CPB) can modify the time of antibiotic serum concentrations. That is why the serum levels of them were measured during open heart procedures. Methods: The prospective study comprised 75 consequent coronary patients randomized in to three groups receiving 1 g of CTZ or 400 mg of CPF or 900 mg of CLIN i.v. with anesthesia induction. Routine coronary surgery with left internal mammary artery harvesting, moderate body hypothermic (30 °C) CPB with crystaloid cardioplegia was performed. Serum antibiotic levels were determined before application, with skin incision, prior CPB induction, after cardioplegia infusion, every 20 minutes of CPB, prior end of CPB, in time of chest closure. Conventional cylinder – plate microbiological assay was used for antibiotic levelmeasurement. Results: All serum antibiotic concentrations showed a sharp decrease immediately after starting CPB and lasted until CPB ended. After initiating of CPB after cardioplegia administration serum concentrations of CTZ (105 min after initial dose) decreased by, on average 55%, CPF (97 min) by 42% and CLIN (116 min) by 78%. Conclusion: CPB can modify the time course of antibiotic serum concentrations. The serum levels of CTZ at the end of the longest procedures were found to be below the MICs for some of the suspected pathogens. We recommend to use higher antibiotic doses for prophylaxis and to administer the second dose with protamin sulphate to obtain maximum concentration in newly formed blood clots.

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.

Multiplex polymerase chain reaction to diagnose bloodstream infections in patients after cardiothoracic surgery

Background

Sepsis and other infectious complications are major causes of mortality and morbidity in patients after cardiac surgery. Whereas conventional blood culture (BC) suffers from low sensitivity as well as a reporting delay of approximately 48–72 h, real-time multiplex polymerase chain reaction (PCR) based technologies like “SeptiFast” (SF) might offer a fast and reliable alternative for detection of bloodstream infections (BSI). The aim of this study was to compare the performance of SF with BC testing in patients suspected of having BSI after cardiac surgery.

Methods

Two hundred seventy-nine blood samples from 169 individuals with suspected BSI were analyzed by SF and BC. After excluding results attributable to contaminants, a comparison between the two groups were carried out. Receiver operating characteristic (ROC) curves were generated to determine the accuracy of clinical and laboratory values for the prediction of positive SF results.

Results

14.7% (n = 41) of blood samples were positive using SF and 17.2% (n = 49) using BC (n.s. [p > 0.05]). In six samples SF detected more than one pathogen. Among the 47 microorganisms identified by SF, only 11 (23.4%) could be confirmed by BC. SF identified a higher number of Gram-negative bacteria than BC did (28 vs. 12, χ² = 7.97, p = 0.005). The combination of BC and SF increased the number of detected microorganisms, including fungi, compared to BC alone (86 vs. 49, χ² = 13.51, p < 0.001). C-reactive protein (CRP) (21.7 ± 11.41 vs. 16.0 ± 16.9 mg/dl, p = 0.009), procalcitonin (28.7 ± 70.9 vs. 11.5 ± 30.4 ng/dl, p = 0.015), and interleukin 6 (IL 6) (932.3 ± 1306.7 vs. 313.3 ± 686.6 pg/ml, p = 0.010) plasma concentrations were higher in patients with a positive SF result. Using ROC analysis, IL-6 (AUC 0.836) and CRP (AUC 0.804) showed the best predictive values for positive SF results.

Conclusion

The SF test represent a valuable method for rapid etiologic diagnosis of BSI in patients after cardiothoracic surgery. In particular this method applies for individuals with suspected Gram-negative blood stream. Due to the low performance in detecting Gram-positive pathogens and the inability to determine antibiotic susceptibility, it should be used in addition to BC only (Pilarczyk K, et al., Intensive Care Med Exp ,3(Suppl. 1):A884, 2015).

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.

Health care-associated infections - an overview

Health care-associated infections (HCAIs) are infections that occur while receiving health care, developed in a hospital or other health care facility that first appear 48 hours or more after hospital admission, or within 30 days after having received health care. Multiple studies indicate that the common types of adverse events affecting hospitalized patients are adverse drug events, HCAIs, and surgical complications. The US Center for Disease Control and Prevention identifies that nearly 1.7 million hospitalized patients annually acquire HCAIs while being treated for other health issues and that more than 98,000 patients (one in 17) die due to these. Several studies suggest that simple infection-control procedures such as cleaning hands with an alcohol-based hand rub can help prevent HCAIs and save lives, reduce morbidity, and minimize health care costs. Routine educational interventions for health care professionals can help change their hand-washing practices to prevent the spread of infection. In support of this, the WHO has produced guidelines to promote hand-washing practices among member countries.

Estimating excess length of stay due to healthcare-associated infections: a systematic review and meta-analysis of statistical methodology

BACKGROUND

Healthcare-associated infection (HCAI) affects millions of patients worldwide. HCAI is associated with increased healthcare costs, owing primarily to increased hospital length of stay (LOS) but calculating these costs is complicated due to time-dependent bias. Accurate estimation of excess LOS due to HCAI is essential to ensure that we invest in cost-effective infection prevention and control (IPC) measures.

AIM

To identify and review the main statistical methods that have been employed to estimate differential LOS between patients with, and without, HCAI; to highlight and discuss potential biases of all statistical approaches.

METHODS

A systematic review from 1997 to April 2017 was conducted in PubMed, CINAHL, ProQuest and EconLit databases. Studies were quality-assessed using an adapted Newcastle-Ottawa Scale (NOS). Methods were categorized as time-fixed or time-varying, with the former exhibiting time-dependent bias. Two examples of meta-analysis were used to illustrate how estimates of excess LOS differ between different studies.

FINDINGS

Ninety-two studies with estimates on excess LOS were identified. The majority of articles employed time-fixed methods (75%). Studies using time-varying methods are of higher quality according to NOS. Studies using time-fixed methods overestimate additional LOS attributable to HCAI. Undertaking meta-analysis is challenging due to a variety of study designs and reporting styles. Study differences are further magnified by heterogeneous populations, case definitions, causative organisms, and susceptibilities.

CONCLUSION

Methodologies have evolved over the last 20 years but there is still a significant body of evidence reliant upon time-fixed methods. Robust estimates are required to inform investment in cost-effective IPC interventions.

Relationship between endotoxin core, staphylococcal and varicella antibody levels and outcome following aortic valve replacement surgery: a prospective observational study

Background

Morbidity and mortality following cardiac valve surgery is high. Immunity is an important contributor to outcome. This study examines the relationship of staphylococcal and endotoxin antibody levels to outcome following cardiac surgery.

Methods

Using enzyme-linked immunosorbent assays (ELISA), we measured pre-operative levels of antibodies to endotoxin core (EndoCAb); 3 common staphylococcal epitopes and varicella on saved serum of 60 adult patients scheduled to undergo elective primary surgical aortic valve replacement (AVR). Primary outcome measure was post-operative length of stay (LOS) in hospital with secondary outcomes being development of infective complications, length of stay on the intensive care unit (ICU) and 30-day mortality. Patients were quartiled according to antibody levels and outcomes compared between the quartile groups using Mann-Whitney tests for length of stay and Fisher's test for development of infection.

Results

Sixty patients (34 M, 26 F) were recruited with mean age 73 years (IQR 66-78), mean body mass index (BMI) 27.7 (IQR 25-31) and EuroSCORE II 1.44 (0.95-1.99). Those patients in the lower quartile for pre-operative antibody level had a longer post-operative stay than the upper quartile. EndoCAb (median IgG level Q1 42.2 MU/ml vs Q4 256 MU/ml) 9 vs 6 days, p = 0.025; alpha-toxin (median IgG level Q1 63 U vs Q4 558 U) 10 vs 7 days, p = 0.034; teichoic acid (median IgG level Q1 14 U vs Q4 419 U) 10 vs 8 days, p = 0.441; staphylococcal enterotoxin A (median IgG level Q1 55 U vs Q4 427 U) 9 vs 7 days, p = 0.865; varicella zoster (median IgG level Q1 1.325 U vs Q4 2.54 U) 8 vs 7 days, p = 1.0; and combined antibody levels 10 vs 6 days, p = 0.017. There were no differences in the number developing post-operative infections for each antibody type. The combined antibody analysis suggested a reduction in proportion of individuals developing infection from the upper vs lower quartile: 0 vs 0.33, p = 0.042.

Conclusions

This study again suggests the inverse relationship between endotoxin core antibody levels and outcome following aortic valve surgery as well as suggesting a similar relationship with antibodies to staphylococcus. There is no such relationship for antibody levels against an organism not providing a peri-operative threat. Understanding this relationship may enable therapeutic manipulation of immune status, re-evaluation of risk and further investigation of the low immune state.

Trial registration

The patients in this study are a sub-group of the RELIEF AS study.ClinicalTrials.gov identifier NCT02174471.

Kinetics of endocan in patients undergoing cardiac surgery with and without cardiopulmonary bypass

BACKGROUND

Endocan plays an important role in the processes of inflammation and infection. The use of cardiopulmonary bypass (CPB) during cardiac surgery can induce an inflammatory response. We aimed to describe the kinetics of endocan in patients undergoing cardiac surgery with and without the use of CPB.

METHODS

Single-centre, observational study with retrospective analysis of prospectively collected data, to compare the kinetics of endocan in patients undergoing isolated coronary artery bypass graft (CABG) surgery. Endocan was measured at induction of general anesthesia (baseline), and at 6, 24, 48 and 72 h after the end of surgery. Patients were classified into two groups, namely those undergoing CPB (CPB group) and those without CPB (off-pump group).

RESULTS

In total, 91 patients were included in this analysis: 61 patients in the CPB group and 30 in the off-pump group. There were no major significant differences between groups. Patients with CPB had a significantly higher level of endocan at 6 h (9.7 ± 6.7 ng/ml vs 6.9 ± 3.3 ng/ml, p = 0.03), but the difference was no longer statistically significant at subsequent timepoints. Endocan values were not significantly correlated with the duration of CPB (p = 0.53).

CONCLUSION

Endocan levels in patients undergoing isolated CABG surgery with CPB are significantly higher at 6 h than in patients with off-pump surgery, and peaks earlier in those with CPB (6 h) than in those undergoing off-pump surgery (24 h).

The "3M" Approach to Cardiovascular Infections: Multimodality, Multitracers, and Multidisciplinary

Cardiovascular infections are associated with high morbidity and mortality. Early diagnosis is crucial for adequate patient management, as early treatment improves the prognosis. The diagnosis cannot be made on the basis of a single symptom, sign, or diagnostic test. Rather, the diagnosis requires a multidisciplinary discussion in addition to the integration of clinical signs, microbiology data, and imaging data. The application of multimodality imaging, including molecular imaging techniques, has improved the sensitivity to detect infections involving heart valves and vessels and implanted cardiovascular devices while also allowing for early detection of septic emboli and metastatic infections before these become clinically apparent. In this review, we describe data supporting the use of a Multimodality, Multitracer, and Multidisciplinary approach (the 3M approach) to cardiovascular infections. In particular, the role of white blood cell SPECT/CT and [¹⁸F]FDG PET/CT in most prevalent and clinically relevant cardiovascular infections will be discussed. In addition, the needs of advanced hybrid equipment, dedicated imaging acquisition protocols, specific expertise for image reading, and interpretation in this field are discussed, emphasizing the need for a specific reference framework within a Cardiovascular Multidisciplinary Team Approach to select the best test or combination of tests for each specific clinical situation.

Low tidal volume mechanical ventilation against no ventilation during cardiopulmonary bypass heart surgery (MECANO): study protocol for a randomized controlled trial

Background

Postoperative pulmonary complications are a leading cause of morbidity and mortality after cardiac surgery. There are no recommendations on mechanical ventilation associated with cardiopulmonary bypass (CPB) during surgery and anesthesiologists perform either no ventilation (noV) at all during CPB or maintain low tidal volume (LTV) ventilation. Indirect evidence points towards better pulmonary outcomes when LTV is performed but no large-scale prospective trial has yet been published in cardiac surgery.

Design

The MECANO trial is a single-center, double-blind, randomized, controlled trial comparing two mechanical ventilation strategies, noV and LTV, during cardiac surgery with CPB. In total, 1500 patients are expected to be included, without any restrictions. They will be randomized between noV and LTV on a 1:1 ratio. The noV group will receive no ventilation during CPB. The LTV group will receive 5 breaths/minute with a tidal volume of 3 mL/kg and positive end-expiratory pressure of 5 cmH2O. The primary endpoint will be a composite of all-cause mortality, early respiratory failure defined as a ratio of partial pressure of oxygen/fraction of inspired oxygen <200 mmHg at 1 hour after arrival in the ICU, heavy oxygenation support (defined as a patient requiring either non-invasive ventilation, mechanical ventilation or high-flow oxygen) at 2 days after arrival in the ICU or ventilator-acquired pneumonia defined by the Center of Disease Control. Lung recruitment maneuvers will be performed in the noV and LTV groups at the end of surgery and at arrival in ICU with an insufflation at +30 cmH20 for 5 seconds. Secondary endpoints are those composing the primary endpoint with the addition of pneumothorax, CPB duration, quantity of postoperative bleeding, red blood cell transfusions, revision surgery requirements, length of stay in the ICU and in the hospital and total hospitalization costs. Patients will be followed until hospital discharge.

Discussion

The MECANO trial is the first of its kind to compare in a double-blind design, a no-ventilation to a low-tidal volume strategy for mechanical ventilation during cardiac surgery with CPB, with a primary composite outcome including death, respiratory failure and postoperative pneumonia.

Trial registration

ClinicalTrials.gov, NCT03098524. Registered on 27 February 2017.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-017-2321-9) contains supplementary material, which is available to authorized users.

Preoperative asymptomatic leukocytosis and postoperative outcome in cardiac surgery patients

BACKGROUND

Despite showing a prognostic value in general surgical patients, preoperative asymptomatic elevated white blood cell (WBC) count is not considered a risk factor for cardiac surgery. Whereas there is sporadic evidence of its value as a preoperative risk marker, it has not been looked at methodically as a specific index of outcome during cardiac surgery. Using a national database we sought to determine the relationship between preoperative WBC count and postoperative outcome in cardiac surgical patients.

METHODS

Cardiac surgeries were extracted from the 2007-2013 American College of Surgeons National Surgical Quality Improvement Program database. Leukocytosis was defined by a preoperative WBC count greater than 11,000 cells/μL. A univariate analysis compared the incidence of adverse outcomes for patients with and without leukocytosis. A multivariate logistic regression model was constructed in order to test whether leukocytosis was an independent predictor of morbidity and mortality.

RESULTS

Out of a total of 10,979 cardiac surgery patients 863 (7.8%) had preoperative leukocytosis. On univariate analysis, patients with leukocytosis experienced greater incidences of 30-day mortality, wound complications, and medical complications. Wound complications included surgical site infection as well as wound dehiscence. The medical complications included all other non-surgical causes of increased morbidity and infection leading to urinary tract infection, pneumonia, ventilator dependence, sepsis and septic shock. After stepwise model adjustment, leukocytosis was a strong predictor of medical complications (OR 1.22, 95% CI: 1.09-1.36, p = 0.002) with c-statistic of 0.667. However, after stepwise model adjustment leukocytosis was not a significant predictor of 30-day mortality and wound complications.

CONCLUSION

Preoperative leukocytosis is associated with adverse postoperative outcome after cardiac surgery and is an independent predictor of infection-related postoperative complications.

Nosocomial infections and antibiotic resistance pattern in open-heart surgery patients at Imam Ali Hospital in Kermanshah, Iran

Background: Patients undergoing open heart surgery have a relatively high risk of acquiring nosocomial infections. The development of antibiotic-resistant infections is associated with prolonged hospital stays and mortalities.

Objectives: The present study was conducted to investigate nosocomial infections and the antibiotic resistance pattern in bacteria causing these infections in open heart surgery patients at Imam Ali Hospital in Kermanshah in the west of Iran over a 4-year period from March 2011 to March 2014.

Materials and methods: The present cross-sectional study was conducted on 135 cases of nosocomial infection among open heart surgery patients. The demographic characteristics and the risk factors of each case of infection were recorded. The antibiotic susceptibility test was carried out using the Minimum Inhibitory Concentration (MIC) method based on the Clinical and Laboratory Standards Institute (CLSI) protocol. The data collected were then analyzed in SPSS-16.

Results: Out of the 6,000 patients who underwent open heart surgery during this 4-year period at the selected hospital, nosocomial infections developed in 135 patients (2.25%), 59.3% of whom were female and 40.7% male. Surgery site infection (SSI), pneumonia (PNEU), urinary tract infection (UTI) and blood stream infection (BSI) affected 52.6%, 37%, 9.6% and 0.8% of the cases, respectively. E.coli, Klebsiella spp. and S. aureus were the most common bacteria causing the nosocomial infections. E. coli was most frequently resistant to imipenem (23.3%) Klebsiella spp. to gentamicin (38.5%) S. aureus to co-trimoxazole (54.2%).

Conclusion: SSI had a high prevalence in this study. Further studies should therefore be conducted to examine the risk factors associated with SSI in open heart surgery. Various studies have shown that antibiotic resistance patterns are different in different regions. Finding a definitive treatment therefore requires an antibiogram.

Pneumonia after cardiac surgery: Experience of the National Institutes of Health/Canadian Institutes of Health Research Cardiothoracic Surgical Trials Network

RATIONALE

Pneumonia remains the most common major infection after cardiac surgery despite numerous preventive measures.

OBJECTIVES

To prospectively examine the timing, pathogens, and risk factors, including modifiable management practices, for postoperative pneumonia and estimate its impact on clinical outcomes.

METHODS

A total of 5158 adult cardiac surgery patients were enrolled prospectively in a cohort study across 10 centers. All infections were adjudicated by an independent committee. Competing risk models were used to assess the association of patient characteristics and management practices with pneumonia within 65 days of surgery. Mortality was assessed by Cox proportional hazards model and length of stay by a multistate model.

MEASUREMENTS AND MAIN RESULTS

The cumulative incidence of pneumonia was 2.4%, 33% of which occurred after discharge. Older age, lower hemoglobin level, chronic obstructive pulmonary disease, steroid use, operative time, and left ventricular assist device/heart transplant were risk factors. Ventilation time (24-48 vs ≤24 hours; hazard ratio [HR], 2.83; 95% confidence interval [95% CI], 1.72-4.66; >48 hours HR, 4.67; 95% CI, 2.70-8.08), nasogastric tubes (HR, 1.80; 95% CI, 1.10-2.94), and each unit of blood cells transfused (HR, 1.16; 95% CI, 1.08-1.26) increased the risk of pneumonia. Prophylactic use of second-generation cephalosporins (HR, 0.66; 95% CI, 0.45-0.97) and platelet transfusions (HR, 0.49, 95% CI, 0.30-0.79) were protective. Pneumonia was associated with a marked increase in mortality (HR, 8.89; 95% CI, 5.02-15.75) and longer length of stay of 13.55 ± 1.95 days (bootstrap 95% CI, 10.31-16.58).

CONCLUSIONS

Pneumonia continues to impose a major impact on the health of patients after cardiac surgery. After we adjusted for baseline risk, several specific management practices were associated with pneumonia, which offer targets for quality improvement and further research.

Glycine Does Not Add to the Beneficial Effects of Perioperative Oral Immune-Enhancing Nutrition Supplements in High-Risk Cardiac Surgery Patients

BACKGROUND

Elderly patients and patients with a poor cardiac function have increased morbidity rates when undergoing cardiac surgery. The aim of this study was to determine whether addition of glycine to a standard preoperative oral immune-enhancing nutrition supplement (OIENS) improves outcome. Glycine-enriched OIENS was compared with 2 formulas: standard OIENS and control.

METHODS

In this double-blind, 3-armed study, patients scheduled to undergo cardiac surgery with the use of extracorporeal circulation received either the glycine-enriched OIENS (OIENS + glyc, n = 24), standard OIENS (OIENS, n = 25), or control formula (Control, n = 25) for minimally 5 preoperative days. Patients were included if they were aged 70 years or older, had a compromised left ventricular function, or were planned for mitral valve surgery. Main outcome measures were postoperative infectious morbidity, organ function, and postoperative recovery.

RESULTS

Infectious morbidity was significantly lower in both treatment groups compared with the control group (p = .02). An infection was diagnosed in 5 and 4 patients in the OIENS + glyc and OIENS groups, respectively, and in 12 control patients. Less supportive therapy was necessary to stabilize circulation in both treatment groups compared with the control group. Median length of hospital stay was 7.0, 6.5, and 8.0 days in the OIENS + glyc, OIENS, and control groups, respectively. Inflammatory responses, as measured by systemic levels of proinflammatory cytokines and surface markers on polymorphonuclear cells, were comparable for all groups.

CONCLUSIONS

Preoperative OIENS reduces postoperative infectious morbidity and results in a more stable circulation; the addition of glycine does not result in any beneficial effect over standard OIENS.

Incidence, microbiological profile of nosocomial infections, and their antibiotic resistance patterns in a high volume Cardiac Surgical Intensive Care Unit

Background:

Nosocomial infections (NIs) in the postoperative period not only increase morbidity and mortality, but also impose a significant economic burden on the health care infrastructure. This retrospective study was undertaken to (a) evaluate the incidence, characteristics, risk factors and outcomes of NIs and (b) identify common microorganisms responsible for infection and their antibiotic resistance profile in our Cardiac Surgical Intensive Care Unit (CSICU).

Patients and Methods:

After ethics committee approval, the CSICU records of all patients who underwent cardiovascular surgery between January 2013 and December 2014 were reviewed retrospectively. The incidence of NI, distribution of NI sites, types of microorganisms and their antibiotic resistance, length of CSICU stay, and patient-outcome were determined.

Results:

Three hundred and nineteen of 6864 patients (4.6%) developed NI after cardiac surgery. Lower respiratory tract infections (LRTIs) accounted for most of the infections (44.2%) followed by surgical-site infection (SSI, 11.6%), bloodstream infection (BSI, 7.5%), urinary tract infection (UTI, 6.9%) and infections from combined sources (29.8%). Acinetobacter, Klebsiella, Escherichia coli, and Staphylococcus were the most frequent pathogens isolated in patients with LRTI, BSI, UTI, and SSI, respectively. The Gram-negative bacteria isolated from different sources were found to be highly resistant to commonly used antibiotics.

Conclusion:

The incidence of NI and sepsis-related mortality, in our CSICU, was 4.6% and 1.9%, respectively. Lower respiratory tract was the most common site of infection and Gram-negative bacilli, the most common pathogens after cardiac surgery. Antibiotic resistance was maximum with Acinetobacter spp.

Hospital-Acquired Infections After Cardiac Surgery and Current Physician Practices: A Retrospective Cohort Study

Background

The management of hospital-acquired infections (HAIs) with respect to physician practices remains largely unexplored despite increasing efforts to standardize care. In the present study, we report findings from a 2-month audit of all patients that have undergone cardiac surgery at a large referral center in Atlantic Canada.

Methods

All patients who underwent cardiac surgical procedures during May and June 2013 at the Queen Elizabeth II Health Sciences Center in Halifax, Nova Scotia were identified. The prevalence of urinary tract infections (UTIs), pneumonia, leg harvest site infections, superficial sternal wound infections, deep sternal wound infections, and sepsis was examined to determine physician approaches in terms of verification rates (microbiology), time of diagnosis and duration of treatment. Continuous variables were compared using Student’s t-test and categorical variables were analyzed using Fischer’s exact test.

Results

A total of 185 consecutive patients underwent cardiac surgical procedures, of which 39 (21%) developed at least one postoperative infection. The overall prevalence of infection types, from highest to lowest, was UTI (8%), pneumonia (7%), leg harvest site infection (5%), superficial surgical site infection (4%), and sepsis (2%). There were no deep sternal wound infections. The overall in-hospital mortality rate was 3.8% with a median length of stay (LOS) of 8 days. The overall infection verification rate was 50% (ranged from 100% in sepsis to 10% in leg harvest site infections). In all cases, a full course of antibiotics was administered despite negative microbiology cultures or limited evidence of an actual infection.

Conclusions

HAIs are commonly treated without being verified and treatment is often not discontinued after negative cultures are received. Our findings highlight the fact that antibiotic treatment is not always supported by evidence, and the effect of this could contribute to increased selective pressure for antimicrobial resistant bacteria.