A model of hemodialysis after acute kidney injury in rats.

BACKGROUND: Acute kidney injury (AKI) is frequent among critically ill patients. Renal replacement therapy (RRT) is often required to deal with severe complications of AKI. This technique is however associated with side effects such as hemodynamic instability and delayed renal recovery. In this study, we aimed to describe a novel model of hemodialysis in rats with AKI and depict a dialysis membrane performance. METHODS: Eighteen Sprague-Dawley rats received 0.75% adenine-rich diet to induce AKI. After 2 weeks, nine underwent an arterio-venous extracorporeal circulation (ECC) (ECC group) for 2 h without a dialysis membrane on the circuit and nine received a hemodialysis session (HD group) for 2 h with an ECC circuit. All rats were hemodynamically monitored, and glomerular filtration rate (GFR) was measured by transcutaneous fluorescence after the injection of FITC-Sinistrin. Blood samples were collected at different time points to assess serum creatinine and serum urea concentrations and to determine the Kt/V. Sinistrin concentration was also quantified in both plasma and dialysis effluent. RESULTS: After 2 weeks of adenine-rich diet, rats exhibited a decrease in GFR. Both serum urea and serum creatinine concentrations increased in the ECC group but remained stable in the HD group. We found no significant difference in serum creatinine and serum urea concentrations between groups. At the end of experiments, mean serum urea was 36.7 mmol/l (95%CI 19.7-46.9 mmol/l) and 23.6 mmol/l (95%CI 15.2-33.5 mmol/l) in the ECC and HD groups, respectively (p = 0.15), and mean serum creatinine concentration was 158.0 µmol/l (95%CI 108.1-191.9 µmol/l) and 114.0 µmol/l (95%CI 90.2-140.9 µmol/l) in the ECC and HD groups, respectively (p = 0.11). The Kt/V of the model was estimated at 0.23. Sinistrin quantity in the ultrafiltrate raised steadily during the dialysis session. After 2 h, the median quantity was 149.2 µg (95% CI 99.7-250.3 µg). CONCLUSIONS: This hemodialysis model is an acceptable compromise between the requirement of hemodynamic tolerance which implies reducing extracorporeal blood volume (using a small dialyzer) and the demonstration that diffusion of molecules through the membrane is achieved.

Toward improvement of knowledge of financial conflicts of interest in a large medical school in France.

INTRODUCTION: Conflict of interests (COIs) adversely affect the integrity of science and public health. The role of medical schools in the teaching and management of COIs has been highlighted by the publication of an annual evaluation of American medical schools based on their COIs policies by the American Medical Student Association (AMSA). A deontological charter was adopted by French medical schools in 2018 but its impact on COI comprehension by students and its effects on COI prevention were not evaluated. METHODS: A 10-item direct survey was conducted among about 1000 students in Paris-Cité University in order to investigate the respect of the charter regarding COIs both in the medical school and in affiliated teaching hospitals. RESULTS: Cumulative results show a satisfying respect of prevention policies regarding COIs in the medical school and hospitals despite the fact that the existence of the charter and its major aspects were insufficiently known. Disclosure of COIs by teachers was insufficient. CONCLUSION: This first direct study among students shows better results than expected according to current non-academic surveys. Moreover, this study demonstrates the feasibility of this kind of survey whose repetition should be an appropriate tool to improve the implementation of the charter within medical schools and teaching hospitals, in particular mandatory disclosure of COIs by teachers.

[Computerized ranking test in three French universities: Staff experience and students' feedback]. / Épreuves informatisées de type ECNi: retour d'expérience sur un test multiuniversité.

BACKGROUND: The year 2016 will be pivotal for the evaluation of French medical students with the introduction of the first computerized National Ranking Test (ECNi). The SIDES, online electronic system for medical student evaluation, was created for this purpose. All the universities have already organized faculty exams but few a joint computerized ranking test at several universities simultaneously. We report our experience on the organization of a mock ECNi by universities Paris Descartes, Paris Diderot and Paris 13. METHODS: Docimological, administrative and technical working groups were created to organize this ECNi. Students in their fifth year of medical studies, who will be the first students to sit for the official ECNi in 2016, were invited to attend this mock exam that represented more than 50% of what will be proposed in 2016. A final electronic questionnaire allowed a docimological and organizational evaluation by students. An analysis of ratings and rankings and their distribution on a 1000-point scale were performed. RESULTS: Sixty-four percent of enrolled students (i.e., 654) attended the three half-day exams. No difference in total score and ranking between the three universities was observed. Students' feedback was extremely positive. Normalized over 1000 points, 99% of students were scored on 300 points only. Progressive clinical cases were the most discriminating test. CONCLUSION: The organization of a mock ECNi involving multiple universities was a docimological and technical success but required an important administrative, technical and teaching investment.

Contribution of the ethics committee of the French society of intensive care medicine to a scenario for the implementation of organ donation after Maastricht III-type cardiac death in France.

French law allows organ donation after death due to cardiocirculatory arrest. In the Maastricht classification, type III non-heart-beating donors are those who experience cardiocirculatory arrest after the withdrawal of life-sustaining treatments. French authorities in charge of regulating organ donation (Agence de la Biomédecine, ABM) are considering organ collection from Maastricht type III donors. We describe a scenario for Maastricht type III organ donation that fully complies with the ethical norms governing care to dying patients. That organ donation may occur after death should have no impact on the care given to the patient and family. The dead-donor rule must be followed scrupulously: the organ retrieval procedure must neither cause nor hasten death. The decision to withdraw life-sustaining treatments, withdrawal modalities, and care provided to the patient and family must adhere strictly to the requirements set forth in patient-rights legislation (the 2005 Léonetti law in France) and should not be influenced in any way by the possibility of organ donation. A major ethical issue regarding the family is how best to transition from discussing treatment-withdrawal decisions to discussing possible organ retrieval for donation should the patient die rapidly after treatment withdrawal. Close cooperation between the healthcare team and the organ retrieval team is crucial to minimize the distress of family members during this transition. Modalities for implementing Maastricht type III organ donation are discussed here, including the best location for withdrawing life-sustaining treatments (operating room or intensive care unit).

[New therapeutic strategies in ARDS]. / Nouveautés thérapeutiques sur le SDRA.

Treatment of acute respiratory distress syndrome (ARDS) has been subject to many researches, sometimes leading to intense controversy. New findings in this field are varied. Effects on prognosis of commonly used treatments for ARDS have recently been investigated. Consistently, prone position, previously known to improve oxygenation without effect on mortality, has been shown to improve survival of the most severely hypoxemic patients. Administration of neuromuscular blocking agents in the acute phase of ARDS has been also shown to be beneficial on survival. In contrast, the exact place of extracorporeal membrane oxygenation (ECMO) in ARDS management remains to be defined despite data suggesting its possible efficiency. In addition, a new era of research has emerged with the advent of cell therapy. Mesenchymal stem cells are able to both promote alveolar epithelium repair and prevent infections. Their efficacy in animal models of ARDS still needs to be confirmed by clinical trials. Finally, other promising therapies including beta-2 adrenergic agonists and omega-3 fatty acids have shown significant limitations in large clinical studies on ARDS.

How to prevent ventilator-induced lung injury?

The experimental evidence that ventilator could injure lungs through the application of excessive end-inspiratory volumes and transpulmonary pressures has led to major changes in the clinical management of patients suffering from the acute respiratory distress syndrome (ARDS). The prevention of ventilator-induced lung injury has become one of the main goals of current ventilator strategies for patients with ARDS as well as for patients with normal lungs that require mechanical ventilation. Tidal volume reduction allowed for a reduction in mortality that confirmed the clinical relevance of ventilator-induced lung injury. In contrast, strategies for setting positive end-expiratory pressure (PEEP) have been proposed but the optimal PEEP level remains unsettled. Considerable efforts have been made within the last decades to try to develop new ventilator strategies as well as pharmacological and mechanical measures in order to prevent VILI and further improve the outcome of ARDS patients. This review will strive to describe seminal experimental and clinical studies that aimed at preventing the development of VILI.

Midodrine treatment for chronic fatigue syndrome.

The long term results of midodrine treatment in a patient having debilitating chronic fatigue syndrome (CFS) are reported. Midodrine treatment, directed at the autonomic nervous system, resulted in correction of the dysautonomia followed by improvement of fatigue. This finding is consistent with the hypothesis that dysautonomia plays a major part in the pathophysiology of CFS and that therapies directed at the autonomic nervous system may be effective in the treatment of CFS.

Ventilator-induced lung injury.

During mechanical ventilation, high end-inspiratory lung volume (whether it be because of large tidal volume (VT) and/or high levels of positive end-expiratory pressure) results in a permeability type pulmonary oedema, called ventilator-induced lung injury (VILI). Previous injury sensitises lung to mechanical ventilation. This experimental concept has recently received a resounding clinical illustration after a 22% reduction of mortality was observed in acute respiratory distress syndrome patients whose VT had been reduced. In addition, it has been suggested that repetitive opening and closing of distal units at low lung volume could induce lung injury but this notion has been challenged both conceptually and clinically after the negative results of the Acute Respiratory Distress Syndrome clinical Network Assessment of Low tidal Volume and Elevated end-expiratory volume to Obviate Lung Injury (ARDSNet ALVEOLI) study. Experimentally and clinically, involvement of inflammatory cytokines in VILI has not been unequivocally demonstrated. Cellular response to mechanical stretch has been increasingly investigated, both on the epithelial and the endothelial side. Lipid membrane trafficking has been thought to be a means by which cells respond to stress failure. Alterations in the respiratory system pressure/volume curve during ventilator-induced lung injury that include decrease in compliance and position of the upper inflection point are due to distal obstruction of airways that reduce aerated lung volume. Information from this curve could help avoid potentially harmful excessive tidal volume reduction.

Continuous versus intermittent infusion of vancomycin in severe Staphylococcal infections: prospective multicenter randomized study.

A continuous infusion of vancomycin (CIV) may provide an alternative mode of infusion in severe hospital-acquired methicillin-resistant staphylococcal (MRS) infections. A multicenter, prospective, randomized study was designed to compare CIV (targeted plateau drug serum concentrations of 20 to 25 mg/liter) and intermittent infusions of vancomycin (IIV; targeted trough drug serum concentrations of 10 to 15 mg/liter) in 119 critically ill patients with MRS infections (bacteremic infections, 35%; pneumonia, 45%). Microbiological and clinical outcomes, safety, pharmacokinetics, ease of treatment adjustment, and cost were compared. Microbiological and clinical outcomes and safety were similar. CIV patients reached the targeted concentrations faster (36 +/- 31 versus 51 +/- 39 h, P = 0.029) and fewer samples were required for treatment monitoring than with IIV patients (7.7 +/- 2.2 versus 11.8 +/- 3.9 per treatment, P < 0.0001). The variability between patients in both the area under the serum concentration-time curve (AUC(24h)) and the daily dose given over 10 days of treatment was lower with CIV than with IIV (variances, 14,621 versus 53,975 mg(2)/liter(2)/h(2) [P = 0.026] and 414 versus 818 g(2) [P = 0.057], respectively). The 10-day treatment cost per patient was $454 +/- 137 in the IIV group and was 23% lower in the CIV group ($321 +/- 81: P < 0.0001). In summary, for comparable efficacy and tolerance, CIV may be a cost-effective alternative to IIV.

Significance of the changes in the respiratory system pressure-volume curve during acute lung injury in rats.

UNLABELLED: The hypothesis that the changes in the respiratory system pressure- volume (PV) curve during pulmonary edema mainly reflect distal airway obstruction was investigated in rats. Normal rats had a well-defined upper inflection point (UIP) at low airway pressure. Airway occlusion by liquid instillation decreased compliance (Crs) and the volume (Vuip) of the UIP, and increased end-inspiratory pressure. The same changes were observed during the progression of edema produced by high volume ventilation (HV). Changes in Vuip and in Crs produced by HV were correlated with edema severity in normal rats or rats with lungs preinjured with alpha-naphthylthiourea. Vuip and Crs changes were proportional, reflecting compression of the PV curve on the volume axis and suggesting reduction of the amount of ventilatable lung at low airway pressure. In keeping with this explanation, the lower Vuip and Crs were before HV, the more severe HV-induced edema was in alpha-naphthylthiourea-injected rats. When edema was profuse, PV curves displayed a marked lower inflection point (LIP), the UIP at low pressure disappeared but another was seen at high volume above the LIP, and the correlation between Vuip changes and edema severity was lost. These observations may have clinical relevance in the context of the "open lung" strategy. KEYWORDS: ventilator-induced lung injury; respiratory mechanics; acute respiratory distress syndrome

Accuracy of delayed cultures of plugged telescoping catheter samples for diagnosing bacterial pneumonia.

OBJECTIVE: It is not always feasible to culture immediately bacteriologic samples of protected pulmonary specimens on a 24-hr basis before starting antibiotic treatment. We have evaluated the effect of delaying the culture of immediate plugged telescoping catheter (PTC) samples performed before starting antibiotherapy. DESIGN: Prospective paired comparisons study. SETTING: Intensive care unit in a university hospital. PATIENTS: Ninety-nine PTCs were performed on 68 intensive care unit patients suspected of nosocomial or community- acquired bacterial pneumonia. INTERVENTION: PTC samples were divided into two aliquots: one for immediate (H0) analysis and one for storage at 4 degrees C (H24) for 24 hrs before being cultured. MEASUREMENTS AND MAIN RESULTS: The results from these delayed cultures (H24) were compared with those from immediate ones (H0). All negative H0 samples (n = 59) were also negative at H24. Forty PTCs yielded one or more microorganisms, with a total of 69 microorganisms in one or both samples. H0 and H24 cultures were concordant in 119 of 128 (97.9%) cases (kappa coefficient value 0.79) with a threshold of 103 colony-forming units (cfu)/mL. Agreement between paired cultures was very good. The bias calculated as the mean difference between paired culture results was 0.128 +/- 1.024 (Deltalog). Concordance using the 103 cfu/mL threshold (102/107 cases, kappa coefficient value 0.82) and agreement were enhanced (0.067 +/- 0.645) when possible contaminants were excluded (n = 21). CONCLUSIONS: Storing PTC specimens for 24 hrs at 4 degrees C is an acceptable alternative when culturing cannot be performed immediately. This allows starting antibiotic treatment without any delay.