Pascal Augustin

Risk factors for multidrug resistant bacteria and optimization of empirical antibiotic therapy in postoperative peritonitis

IntroductionThe main objective was to determine risk factors for presence of multidrug resistant bacteria (MDR) in postoperative peritonitis (PP) and optimal empirical antibiotic therapy (EA) among options proposed by Infectious Disease Society of America and the Surgical Infection Society guidelines.MethodsOne hundred patients hospitalised in the intensive care unit (ICU) for PP were reviewed. Clinical and microbiologic data, EA and its adequacy were analysed. The in vitro activities of 9 antibiotics in relation to the cultured bacteria were assessed to propose the most adequate EA among 17 regimens in the largest number of cases.ResultsA total of 269 bacteria was cultured in 100 patients including 41 episodes with MDR. According to logistic regression analysis, the use of broad-spectrum antibiotic between initial intervention and reoperation was the only significant risk factor for emergence of MDR bacteria (odds ratio (OR) = 5.1; 95% confidence interval (CI) = 1.7 - 15; P = 0.0031). Antibiotics providing the best activity rate were imipenem/cilastatin (68%) and piperacillin/tazobactam (53%). The best adequacy for EA was obtained by combinations of imipenem/cilastatin or piperacillin/tazobactam, amikacin and a glycopeptide, with values reaching 99% and 94%, respectively. Imipenem/cilastin was the only single-drug regimen providing an adequacy superior to 80% in the absence of broad spectrum antibiotic between initial surgery and reoperation.ConclusionsInterval antibiotic therapy is associated with the presence of MDR bacteria. Not all regimens proposed by Infectious Disease Society of America and the Surgical Infection Society guidelines for PP can provide an acceptable rate of adequacy. Monotherapy with imipenem/cilastin is suitable for EA only in absence of this risk factor for MDR. For other patients, only antibiotic combinations may achieve high adequacy rates.

Clinical review: Intrapericardial fibrinolysis in management of purulent pericarditis

Purulent pericarditis (PP) is a potentially life-threatening disease. Reported mortality rates are between 20 and 30%. Constrictive pericarditis occurs over the course of PP in at least 3.5% of cases. The frequency of persistent PP (chronic or recurrent purulent pericardial effusion occurring despite drainage and adequate antibiotherapy) is unknown because this entity was not previously classified as a complication of PP. No consensus exists on the optimal management of PP. Nevertheless, the cornerstone of PP management is complete eradication of the focus of infection. In retrospective studies, compared to simple drainage, systematic pericardiectomy provided a prevention of constrictive pericarditis with better clinical outcome. Because of potential morbidity associated with pericardiectomy, intrapericardial fibrinolysis has been proposed as a less invasive method for prevention of persistent PP and constrictive pericarditis. Experimental data demonstrate that fibrin formation, which occurs during the first week of the disease, is an essential step in the evolution to constrictive pericarditis and persistent PP. We reviewed the literature using the MEDLINE database. We evaluated the clinical efficacy, outcome, and complications of pericardial fibrinolysis. Seventy-four cases of fibrinolysis in PP were analysed. Pericarditis of tuberculous origin were excluded. Among the 40 included cases, only two treated by late fibrinolysis encountered failure requiring pericardiectomy. No patient encountered clinical or echocardiographic features of constriction during follow-up. Only one serious complication was described. Despite the lack of definitive evidence, potential benefits of fibrinolysis as a less invasive alternative to surgery in the management of PP seem promising. Early consideration should be given to fibrinolysis in order to prevent both constrictive and persistent PP. Nevertheless, in case of failure of fibrinolysis, pericardiectomy remains the primary option for complete eradication of infection.

Preoperative Statin Treatment Is Associated With Reduced Postoperative Mortality After Isolated Cardiac Valve Surgery in High-Risk Patients

OBJECTIVE The aim of the present study was to assess the influence of preoperative statin therapy on postoperative mortality in high-risk patients after isolated valve surgery. DESIGN An observational cohort study. SETTING A 1,200-bed university hospital. PARTICIPANTS All consecutive patients undergoing isolated nonemergent valve surgery with cardiopulmonary bypass between November 2005 and December 2007 were included. INTERVENTION None. MEASUREMENTS AND MAIN RESULTS During the period, 772 consecutive patients underwent nonemergent isolated valve surgery. Among them, 430 were high cardiovascular risk (defined by patients with 2 or more cardiovascular risk factors). In the high-risk cardiovascular patients, statin pretreatment was administered in 222 patients (52%). In multivariate analysis, after adjustment with a propensity score analysis, preoperative statin therapy was associated with a significant reduction of postoperative mortality in patients with high risk (odds ratio = 0.41; 95% confidence interval, 0.17-0.97; p = 0.04). Low left ventricular ejection fraction and elevated pulmonary artery pressure also were independently associated with increased postoperative mortality. By contrast, in the low-risk patient group, few patients received preoperative statin therapy (7%). CONCLUSIONS This study suggests that preoperative statin therapy may have a potential beneficial effect on postoperative mortality after isolated cardiac valve surgery in high-risk cardiovascular patients.

Abdominal Compartment Syndrome Due to Extracorporeal Membrane Oxygenation in Adults

Extracorporeal membrane oxygenation (ECMO) improves the outcome of refractory cardiogenic shock. Few studies in adult populations have specifically addressed the complications of ECMO. Abdominal compartment syndrome (ACS) has been previously described in the pediatric literature, but it has never been directly attributed to ECMO alone. The authors describe two cases of ACS directly induced by venoarterial ECMO. In one case, decompressive laparotomy restored an adequate hemodynamic status. The authors hypothesize that ECMO contributed to ACS by inducing massive fluid overload and subsequent tense ascites. In conclusion, when ECMO dysfunction or hemodynamic impairment occurs, ACS should be considered and a decompressive laparotomy should be performed.

A Comparison of a Machine Learning Model with EuroSCORE II in Predicting Mortality after Elective Cardiac Surgery: A Decision Curve Analysis

Background The benefits of cardiac surgery are sometimes difficult to predict and the decision to operate on a given individual is complex. Machine Learning and Decision Curve Analysis (DCA) are recent methods developed to create and evaluate prediction models. Methods and finding We conducted a retrospective cohort study using a prospective collected database from December 2005 to December 2012, from a cardiac surgical center at University Hospital. The different models of prediction of mortality in-hospital after elective cardiac surgery, including EuroSCORE II, a logistic regression model and a machine learning model, were compared by ROC and DCA. Of the 6,520 patients having elective cardiac surgery with cardiopulmonary bypass, 6.3% died. Mean age was 63.4 years old (standard deviation 14.4), and mean EuroSCORE II was 3.7 (4.8) %. The area under ROC curve (IC95%) for the machine learning model (0.795 (0.755–0.834)) was significantly higher than EuroSCORE II or the logistic regression model (respectively, 0.737 (0.691–0.783) and 0.742 (0.698–0.785), p < 0.0001). Decision Curve Analysis showed that the machine learning model, in this monocentric study, has a greater benefit whatever the probability threshold. Conclusions According to ROC and DCA, machine learning model is more accurate in predicting mortality after elective cardiac surgery than EuroSCORE II. These results confirm the use of machine learning methods in the field of medical prediction.

Pseudomonas aeruginosa Post-Operative Peritonitis: Clinical Features, Risk Factors, and Prognosis

BACKGROUND Postoperative peritonitis (PP) is associated with a high rate of multi-drug-resistant micro-organisms. The role of Pseudomonas aeruginosa in this condition has never been assessed. We evaluated the risk factors and prognosis for PP caused by P. aeruginosa. METHODS Patients hospitalized in the intensive care unit (ICU) after re-operation for PP were identified prospectively. Analyses were performed retrospectively. Specific risk factors were investigated by comparing P. aeruginosa PP with PP having other causes. The main outcome endpoint was death in the hospital. RESULTS We found 55 P. aeruginosa PP among the 349 cases of PP (16%) in the ICU over 14 years. Factors associated with the presence of P. aeruginosa in peritoneal fluid culture were Acute Physiology and Chronic Health Evaluation (APACHE) II score (odds ratio [OR] 1.1; 95% confidence interval [CI] 1.02-1.09; p=0.004) and respiratory failure (OR 2.3; 95% CI 1.26-4.16; p=0.006). These criteria performed poorly in predicting P. aeruginosa PP. Such infections were associated with a higher hospital mortality rate, but not after adjustment for the severity score. Adequate antibiotic therapy comprising two antibiotics effective against P. aeruginosa was associated with a lower mortality rate for P. aeruginosa PP in the ICU. CONCLUSION The prevalence of P. aeruginosa PP is not high. Risk factors do not allow accurate prediction of the infection. Our data suggest two drugs effective against P. aeruginosa should be considered for treating these infections.

Accuracy of a feedback device for cardiopulmonary resuscitation on a dental chair

Background Conflicting studies exist about the effectiveness of cardiopulmonary resuscitation (CPR) on a dental chair. In some situations, dental surgeons are obliged to perform CPR with the patient on the chair. Feedback devices are supposed to guide the compression depth in order to improve the quality of CPR, but some devices are based on an accelerometer that can theoretically report erroneous results because of the lack of rigidity of a dental chair. Objective The aim of this study was to evaluate the accuracy of these devices to guide chest compressions on a dental chair. Methods A prospective, randomised, crossover, equivalence/non-inferiority study was conducted to compare the values of compression depths provided by the feedback device (Real CPR Help®, delivered by Zoll© Medical Corporation, Chelmsford, MA, USA) with the real measurements provided by the manikin (Resusci Anne® Advanced SkillTrainer, Laerdal Medical AS©, Norway). Chest-compression-only CPR was performed by 15 Basic Life Support instructors who carried out two rounds of continuous CPR for 2 min each. Data were analysed with a correlation test, a Bland–Altman method and a Wilcoxon test. Statistical significance was defined as p<0.05. Results A significant difference was found between the mean depths of compression measured by the feedback device and the manikin on a dental chair and on the floor (p<0.0001). The feedback device overestimated the depth of chest compressions, and Bland–Altman analysis demonstrated poor agreement. Conclusion This study indicates that feedback devices with accelerometer technology are not sufficiently reliable to ensure adequate chest compression on dental chairs.

Assessment of the National French recommendations regarding the dosing regimen of 8 mg/kg of gentamicin in patients hospitalised in intensive care units

INTRODUCTION To assess the French National Agency for Medicines and Health Products Safety (ANSM) guidelines concerning the peak plasma concentration (Cmax) of gentamicin when using a loading dose of 8mg/kg administered in patients hospitalised in the intensive care unit (ICU). PATIENTS AND METHODS A prospective observational cohort study conducted in one ICU. RESULTS During the study period, 34 patients with a median simplified acute physiology score 2 of 54 [44-70] received a median dose of 8 [7.9-8.1] mg/kg of gentamicin. The median Cmax was 17.5 [15.4-20.7] mg/L and no patient had a Cmax>30mg/L. Twenty-four of 34 patients (71%) had a Cmax>16mg/L. Following multivariate analysis, the only factor associated with Cmax<16mg/L was a positive fluid balance 24hours before gentamicin administration (per 1000mL increment) (OR: 0.37, 95% CI: 0.18-0.77, P=0.008). CONCLUSIONS These results suggest that a Cmax>30mg/L [which corresponds to approximately 8 times the minimal inhibiting concentrations (MIC) breakpoints for Pseudomonas aeruginosa and Enterobacteriaceae with intermediate sensitivity] of gentamicin as recommended by ANSM guidelines seems impossible to obtain with a loading dose of 8mg/kg in the ICU. A loading dose of 8mg/kg should probably not be used in the empiric antibiotic treatment of infection due to non-fermenting Gram-negative bacilli and Enterobacteriaceae with intermediate sensitivity whose MIC breakpoint is 4mg/L. A Cmax>16mg/L was not reached in almost 30% of patients, particularly in the group with a positive fluid balance who require higher doses than currently recommended.

Diagnosis and management of the postoperative surgical and medical complications of bariatric surgery

Perioperative complications following bariatric surgery (BS) have been poorly analysed and their management is not clearly assessed. The associated frequency of ICU admission is difficult to estimate. Among surgical complications, digestive perforations are the most frequent. The most common postoperative complications of sleeve gastrectomy are fistulas, but bleeding on the stapling line is also commonly reported. Complication rates are higher after Roux-en-Y gastric bypass, mainly due to anastomotic leaks. Medical complications are mainly thromboembolic or respiratory complications. All these surgical and medical complications are not easily detected; clinical signs can be atypical or insidious, often resulting in delayed management. Respiratory signs can be predominant and lead erroneously to pulmonary or thromboembolic diseases. Diagnostic criteria are based on minor clinical signs, tachycardia being probably the most frequent one. Lately, complications are revealed by haemodynamic instability, respiratory failure or renal dysfunction and radiographic findings. Management decision according to these abnormal signs is based on a combined multidisciplanary approach including surgical and/or endoscopic procedures and medical care, depending on the nature and severity of the surgical complication. Medical management is based on supportive ICU care of organ dysfunctions, curative anticoagulation if required, nutritional support, and appropriate anti-infective therapy. Pharmacological data are limited in morbidly obese patients and the appropriate doses are debated, especially for anti-infective agents. Complicated BS cases have a poor outcome, probably largely related to delayed diagnosis and reoperation.

Extracorporeal Membrane Oxygenation in 5 Patients With Bronchial Fistula With Severe Acute Lung Injury

PURPOSE The management of bronchial fistula associated with acute lung injury raises two major concerns: (1) high ventilation pressures are necessary for lung recruitment but detrimental for fistula healing, and (2) adequate lung recruitment is prevented by large air leak. Primary surgical closure of bronchial fistula should be attempted but is rarely successful during mechanical ventilation. We sought to evaluate the efficacy of extracorporeal membrane oxygenation associated with lung-protective ventilation in case of failure of conventional management. DESCRIPTION Arteriovenous extracorporeal membrane oxygenation was initiated by femorofemoral cannulation. A stepwise increase of extracorporeal membrane oxygenation output and a decrease of mechanical ventilation settings were simultaneously performed, aiming at lung-protective ventilation. EVALUATION During a 1-year period, this protocol management was used in 5 patients with refractory respiratory failure associated with bronchial fistula after thoracic operations. This strategy allowed fistula healing in 3 patients. CONCLUSIONS If correctly timed, extracorporeal membrane oxygenation can provide a therapeutic bridge to lung-protective ventilation and allow bronchial fistula healing in case of refractory respiratory failure.