Determinants of beta-lactam PK/PD target attainment in critically ill patients: A single center retrospective study

PURPOSE

We aimed to identify factors associated with achieving target BL plasma concentrations and describe real world data for therapeutic drug monitoring (TDM).

METHODS

A retrospective single center study was conducted. We collected data from patients admitted to ICU with at least one BL TDM. We assessed the proportion of patients attaining the recommended plasma concentrations (i.e 100%fT > 4 to 8 MIC). Univariate and multivariate analyses was performed to identify the determinants of BL target attainment.

RESULTS

156 patients were included. At the first dosing, 34% achieved target BL plasma concentrations, 50% were overdosed, and 16% were underdosed. Median time for 1st TDM were 4 (SD = 2.9) days. Multivariate analysis revealed that CKD-EPI estimated glomerular filtration rate (OR = 1.02; CI [1.01; 1.03]; p < 0.0001) and total body weight (OR = 1.03; CI [1.01; 1.04]; p = 0.0048) were the main determinant of BL target attainment. Conversely, Continuous Renal Replacement Therapy (OR = 0.28; CI [0.09; 0.89]; p = 0.0318) and meropenem use (OR = 0.31; CI [0.14; 0.69]; p = 0.0041) were identified as risk factors for overdosing. No factor was associated with underdosing.

CONCLUSION

Achieving target BL plasma concentrations remains challenging in ICUs. Identifying predictive factors of BL target attainment would favor implementing rapid dosing optimization strategies in both under and overdosing high risk patients.

Proportionate universalism intervention is effective for tackling nutritional social gradient in adolescents: the PRALIMAP-INÈS mixed randomised trial

OBJECTIVE

This study aimed to investigate the effectiveness of proportionate universalism intervention to reduce the slope of the nutritional social gradient in adolescents.

STUDY DESIGN

A mixed (experimental and quasi-experimental) multicentre trial.

METHODS

Data from 985 adolescents of the PRALIMAP-INÈS trial (North-eastern France, 2012-2015) were analysed. For this, adolescents were split into five social classes according to the Family Affluence Scale: Highly Less Advantaged (H.L.Ad; n = 33), Less Advantaged (L.Ad; n = 155), Intermediate (Int; n = 404), Advantaged (Ad; n = 324) and Highly Advantaged (H.Ad; n = 69). The overweight care management was a standard care for all and a strengthened one adapted to the social class of adolescents. The main outcome was the 1-year change of the body mass index z-score (BMIz) slope. Other nutritional outcomes were BMI, ΔBMI_p95 (BMI minus 95th percentile of the WHO reference), %BMI_p95 (percent of 95th percentile of the WHO reference), leisure-time sport, consumption of fruits and vegetables and consumption of sugary foods and drinks.

RESULTS

The inclusion data confirmed a weight social gradient expressed by a significant BMIz linear regression coefficient (β = -0.09 [-0.14 to -0.04], P < 0.0001). The higher the social class, the lower the BMIz. The 1-year BMIz linear regression coefficient was -0.07 [-0.12 to -0.02], corresponding to a significant weight social gradient reduction of 23.3% (β = 0.021 [0.001 to 0.041]; P = 0.04). Consistent results were found for other nutritional outcomes.

CONCLUSIONS

PRALIMAP-INÈS shows that proportionate universalism intervention is effective to reduce the adolescents' nutritional social gradient and suggests that equitable health programmes and policies are a realistic goal.

P27: INTRODUCTION OF A PILOT VIRTUAL FRACTURE CLINIC: A TIME AND COST ANALYSIS

Introduction

The British Orthopaedic Association Standards for Trauma and Orthopaedics(BOAST) have produced guidelines advising that all patients be reviewed by an orthopaedic consultant within 72 hours of presentation. However, data from traditional fracture clinics rarely fulfil this criterion. Furthermore, data from the National Health Service(NHS) has determined that traditional fracture clinics have become unfit for purpose with low patient satisfaction rates, excessive waiting times and over 6.9 million missed appointments every year. Our aim is to test the feasibility of a virtual fracture clinic(VFC) with a view to reducing service costs and improving adherence to BOAST guidelines specified timeline for orthopaedic consultant review.

Method

A retrospective analysis of 103 patients referred to our pilot VFC from January 1st to 31st 2019 was carried out. We included shoulder dislocations, clavicle injuries, simple distal radius fractures, radial head fractures, metacarpal and metatarsal injuries, undisplaced fractures of the medial and lateral malleolus of the ankle and soft tissue injuries. The primary outcome measured time from presentation to review by an orthopaedic consultant. A cost analysis was also performed to estimate the overheads and potential savings associated with VFC introduction. Statistical analysis was done via SPSS.

Result

Following VFC establishment, time from ED presentation to review by orthopaedic consultant reduced from a mean of 229 hours to 72 hours(P=0.0001). Cost analysis demonstrated that the VFC created savings of €3170 per week, amounting to projected savings of €38,040.

Conclusion

VFC has the potential to improve clinical performance while delivering substantial financial savings.

Take-home message

Virtual fracture clinic improves patients review times bringing them in line with BOAST guidelines while providing significant reductions in overheads leading to potential savings of over 38,000 euro.

Exosomes: nanodust?

Until recently, exosomes were considered to be dust in electron microscopy. This perception has changed dramatically in the past few years. A new research field has emerged aiming to describe the formation, release, and function of these nanoparticles. The role of exosomes evolved from garbage bins to biologically active, selectively secreted particles that are part of a novel and broader messaging system. They were shown to display immunomodulatory properties. Today, exosomes are regarded as attractive targets for diagnostic and therapeutic purposes, especially in the field of oncology.

P4499Development of a hydrogel-based pre-vascularized 3D cardiac patch displaying capillary network

Purpose

Stem cell-based attempts at regenerating chronically failing heart have not met the clinical outcomes expected by experimental studies. The efficacy of cell transplant is largely dependent on the engraftment rate, which requires cells to receive an adequate blood supply. To address this issue, we propose to develop a composite tissue engineering construct made of biocompatible pre-vascularized fibrin hydrogel. The objectives of this study are to determine co-culture conditions and to optimize fabrication of fibrin hydrogels supporting generation of capillaries and cardiomyocyte activity at the same time.

Materials and methods

Rat primary cardiomyocytes were co-seeded with human umbilical vein endothelial cells (HUVECs) in fibrin hydrogels. Cultures were performed in 96 well plates. Cells were cultured in a mixture of medium conditioned with human dermal fibroblasts and of cardiomyocyte medium (1:1) for 8 days. To improve co-culture of the two cell types, insulin (1 μg/mL) and/or VEGF (5 ng/mL) were added 24 hours after the initial day of culture and maintained for 24 hours. The cells treated with VEGF were also treated 5 days after initial seeding with insulin and VEGF (insulin at 1 μg/mL and VEGF at 1 or 5 ng/mL). After culture, cardiomyocytes were immuno-stained for Troponin T or Connexin-43, endothelial cells for CD31, basement membrane for collagen IV. From spinning disk images, cardiomyocyte volume, contraction and total length/ branches of capillaries were measured.

Results

: We first determine the best conditions allowing the generation of active cardiomyocytes and the formation of a network of mature capillaries into fibrin hydrogels. We showed that cardiomyocytes volume and contraction were not influenced by the addition of VEGF or insulin. For cells treated with VEGF for 24 hours, total length and total branches of capillaries were significantly increased over other conditions without supplements (control), or with insulin alone or with VEGF. We also observed lumen formation and basement membrane deposition.

Conclusions

These results may provide a new model of vascularized human heart tissue for in vitro studies, displaying cardiomyocyte contractility together with lumenized capillary formation. Furthermore, our data may help overcome current obstacles toward the success of cardiac cell therapy for damaged myocardium. In such approach, endothelial capillaries will serve as structural and trophic support through inosculation with the host cardiac vasculature after epicardial graft. As a perspective of this work, and in order to improve the cardiomyocyte alignment and the development of capillaries, we will design specific PDMS mold to allow the formation of a micro-tissue. Application of human cardiac cells and implantation in in vivo model is expected.

Acknowledgement/Funding

ESC research grant, Fondation de l'avenir, Societe Francaise de Cardiologie, Institut Servier

Comparison of different techniques of central venous pressure measurement in mechanically ventilated critically ill patients

BACKGROUND

Several techniques exist for measuring central venous pressure (CVP) but little information is available about the accuracy of each method. The aim of this study was to compare different methods of CVP measurements in mechanically ventilated patients.

METHODS

CVP was measured in mechanically ventilated patients without spontaneous breathing using four different techniques: 1) end expiratory CVP measurement at the base of the" c" wave (CVP_MEASURED), chosen as the reference method; 2) CVP measurement from the monitor averaging CVP over the cardiac and respiratory cycles (CVP_MONITOR); 3) CVP measurement after a transient withdrawing of mechanical ventilation (CVP_NADIR); 4) CVP measurement corrected for the transmitted respiratory pressure induced by intrinsic PEEP (calculated CVP: CVP_CALCULATED). Bias, precision, limits of agreement, and proportions of outliers (difference > 2 mm Hg) were determined.

RESULTS

Among 61 included patients, 103 CVP assessments were performed. CVP_MONITOR bias [-0.87  (1.06) mm Hg] was significantly different from those of CVP_CALCULATED [1.42  (1.07), P < 0.001 and CVP_NADIR (1.04  (1.29), P < 0.001]. The limits of agreement of CVP_MONITOR [-2.96 to 1.21 mm Hg] were not significantly different to those of CVP_NADIR (-1.49 to 3.57 mm Hg, P = 0.39) and CVP_CALCULATED (-0.68 to 3.53 mm Hg, P = 0.31). The proportion of outliers was not significantly different between CVP_MONITOR (n = 5, 5%) and CVP_NADIR (n = 9, 9%, P = 0.27) but was greater with CVP_CALCULATED (n = 16, 15%, P = 0.01).

CONCLUSIONS

In mechanically ventilated patients, CVP_MONITOR is a reliable method for assessing CVP_MEASURED Taking into account transmitted respiratory pressures, CVP_CALCULATED had a higher proportion of outliers and precision than CVP_NADIR.

Comparison of two ultrasound guided approaches for axillary vein catheterization: a randomized controlled non-inferiority trial

BACKGROUND

Axillary vein catheterization via a distal approach is an alternative to the proximal approach to axillary/subclavian vein catheterization under ultrasound (US) guidance. The aim of this trial was to compare the two approaches.

METHODS

In a randomized single-centre study, all patients requiring central vein catheterization in intensive care or the operating room were randomly assigned to proximal or distal approach groups. If catheterization failed after two attempts using the approach allocated, the non-allocated approach was used. The primary endpoint was the initial success rate of distal to compared with the proximal approach, using a non-inferiority analysis (lower limit 90% CI greater than -8% non-inferiority margin for group difference). The secondary endpoints were: overall success rates, catheter position and complications.

RESULTS

119/122 included patients were analysed (57 and 62 in the proximal and distal axillary approach groups, respectively). Primary success rates for proximal and distal sites were 87.7 and 85.5%, respectively (difference -2.2%, 90% CI [-12.5-8.1%], non-inferiority P=0.18). The proximal and distal overall success rates were 96.5 and 98.4%, respectively (difference -1.9%, 90% CI [-4.9-8.7%], non-inferiority P<0.01). Thrombogenic catheter positions were 7 (12.3%) in proximal approach group vs 19 (31.7%) in the distal approach group (P=0.01). Complications were comparable in the two groups (2 (3.3%) vs 4 (6.5%), P=0.68).

CONCLUSION

In terms of absolute and overall success rates, a distal approach is not non-inferior to a proximal approach. Although associated with a more thrombogenic catheter extremity position, the distal approach can be considered as a rescue alternative after failure of a proximal approach.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT01543360.

Phenotypic and functional characteristics of CD39high human regulatory B cells (Breg)

CD39 and CD73 are key enzymes in the adenosine (ADO) pathway. ADO modulates pathophysiological responses of immune cells, including B cells. It has recently emerged that a subpopulation of ADO-producing CD39⁺CD73⁺ B cells has regulatory properties. Here, we define the CD39^high subset of these cells as the major contributor to the regulatory network operated by human B lymphocytes. Peripheral blood B cells were sorted into CD39^neg, CD39^inter and CD39^high subsets. The phenotype, proliferation and IL-10 secretion by these B cells were studied by flow cytometry. 5'-AMP and ADO levels were measured by mass spectrometry. Agonists or antagonists of A₁R, A_2AR and A₃R were used to study ADO-receptor signaling in B cells. Inhibition of effector T-cell (Teff) activation/proliferation by B cells was assessed in co-cultures. Cytokine production was measured by Luminex. Upon in vitro activation and culture of B cells, the subset of CD39^high B cells increased in frequency (p < 0.001). CD39^high B cells upregulated CD73 expression, proliferated (approximately 40% of CD39^high B cells were Ki-67⁺ and secreted fold-2 higher IL-10 and ADO levels than CD39^neg or CD39^inter B cells. CD39^high B cells co-cultured with autologous Teff suppressed T-cell activation/proliferation and secreted elevated levels of IL-6 and IL-10. The A₁R and A_2AR agonists promoted expansion and functions of CD39^high B cells. CD39 ectonucleotidase is upregulated in a subset of in vitro-activated B cells which utilize ADO and IL-10 to suppress Teff functions. Proliferation and functions of these CD39^high B cells are regulated by A₁R- and A_2AR-mediated autocrine signaling.

How Tissue Mechanical Properties Affect Enteric Neural Crest Cell Migration

Neural crest cells (NCCs) are a population of multipotent cells that migrate extensively during vertebrate development. Alterations to neural crest ontogenesis cause several diseases, including cancers and congenital defects, such as Hirschprung disease, which results from incomplete colonization of the colon by enteric NCCs (ENCCs). We investigated the influence of the stiffness and structure of the environment on ENCC migration in vitro and during colonization of the gastrointestinal tract in chicken and mouse embryos. We showed using tensile stretching and atomic force microscopy (AFM) that the mesenchyme of the gut was initially soft but gradually stiffened during the period of ENCC colonization. Second-harmonic generation (SHG) microscopy revealed that this stiffening was associated with a gradual organization and enrichment of collagen fibers in the developing gut. Ex-vivo 2D cell migration assays showed that ENCCs migrated on substrates with very low levels of stiffness. In 3D collagen gels, the speed of the ENCC migratory front decreased with increasing gel stiffness, whereas no correlation was found between porosity and ENCC migration behavior. Metalloprotease inhibition experiments showed that ENCCs actively degraded collagen in order to progress. These results shed light on the role of the mechanical properties of tissues in ENCC migration during development.

Population pharmacokinetics of linezolid in critically ill patients on renal replacement therapy: comparison of equal doses in continuous venovenous haemofiltration and continuous venovenous haemodiafiltration

OBJECTIVES

Few data are available to guide linezolid dosing during renal replacement therapy. The objective of this study was to compare the population pharmacokinetics of linezolid during continuous venovenous haemofiltration (CVVHF, 30 mL/kg/h) and continuous venovenous haemodiafiltration (CVVHDF, 15 mL/kg/h + 15 mL/kg/h).

METHODS

Patients requiring linezolid 600 mg iv every 12 h and CVVHF or CVVHDF were eligible for this prospective study. Seven blood samples were collected over one dosing interval and analysed by a validated chromatographic method. Population pharmacokinetic analysis was undertaken using Pmetrics. Monte Carlo simulations evaluated achievement of a pharmacodynamics target of an AUC from 0-24 h to MIC (AUC0-24/MIC) of 80.

RESULTS

Nine CVVHDF and eight CVVHF treatments were performed in 13 patients. Regimens of CVVHDF and CVVHF were similar. A two-compartment linear model best described the data. CVVHDF was associated with a 20.5% higher mean linezolid clearance than CVVHF, without statistical significance (P = 0.39). Increasing patient weight and decreasing SOFA score were associated with increasing linezolid clearance. The mean (SD) parameter estimates were: clearance (CL), 3.8 (2.2) L/h; volume of the central compartment, 26.5 (10.3) L; intercompartmental clearance constants from central to peripheral, 8.1 (12.1) L/h; and peripheral to central compartments, 3.6 (4.0) L/h. Achievement of pharmacodynamic targets was poor for an MIC of 2 mg/L with the studied dose.

CONCLUSIONS

During CVVHF and CVVHDF, there is profound pharmacokinetic variability of linezolid. Suboptimal achievement of therapeutic targets occurs at the EUCAST breakpoint MIC of 2 mg/L using 600 mg iv every 12 h.

Large and prolonged food-borne multistate hepatitis A outbreak in Europe associated with consumption of frozen berries, 2013 to 2014

In May 2013, Italy declared a national outbreak of hepatitis A, which also affected several foreign tourists who had recently visited the country. Molecular investigations identified some cases as infected with an identical strain of hepatitis A virus subgenotype IA. After additional European Union/European Economic Area (EU/EEA) countries reported locally acquired and travel-related cases associated with the same outbreak, an international outbreak investigation team was convened, a European outbreak case definition was issued and harmonisation of the national epidemiological and microbiological investigations was encouraged. From January 2013 to August 2014, 1,589 hepatitis A cases were reported associated with the multistate outbreak; 1,102 (70%) of the cases were hospitalised for a median time of six days; two related deaths were reported. Epidemiological and microbiological investigations implicated mixed frozen berries as the vehicle of infection of the outbreak. In order to control the spread of the outbreak, suspected or contaminated food batches were recalled, the public was recommended to heat-treat berries, and post-exposure prophylaxis of contacts was performed. The outbreak highlighted how large food-borne hepatitis A outbreaks may affect the increasingly susceptible EU/EEA general population and how, with the growing international food trade, frozen berries are a potential high-risk food.

Human CD4+ CD39+ regulatory T cells produce adenosine upon co-expression of surface CD73 or contact with CD73+ exosomes or CD73+ cells

While murine CD4(+) CD39(+) regulatory T cells (T(reg)) co-express CD73 and hydrolyze exogenous (e) adenosine triphosphate (ATP) to immunosuppressive adenosine (ADO), surface co-expression of CD73 on human circulating CD4(+) CD39(+) T(reg) is rare. Therefore, the ability of human T(reg) to produce and utilize ADO for suppression remains unclear. Using mass spectrometry, we measured nucleoside production by subsets of human CD4(+) CD39(+) and CD4(+) CD39(-)CD73(+) T cells or CD19(+) B cells isolated from blood of 30 volunteers and 14 cancer patients. CD39 and CD73 expression was evaluated by flow cytometry, Western blots, confocal microscopy or reverse transcription-polymerase chain reaction (RT-PCR). Circulating CD4(+) CD39(+) T(reg) which hydrolyzed eATP to 5'-AMP contained few intracytoplasmic granules and had low CD73 mRNA levels. Only ∼1% of these T(reg) were CD39(+) CD73(+) . In contrast, CD4(+) CD39(neg) CD73(+) T cells contained numerous CD73(+) granules in the cytoplasm and strongly expressed surface CD73. In vitro-generated T(reg) (Tr1) and most B cells were CD39(+) CD73(+) . All these CD73(+) T cell subsets and B cells hydrolyzed 5'-AMP to ADO. Exosomes isolated from plasma of normal control (NC) or cancer patients carried enzymatically active CD39 and CD73(+) and, when supplied with eATP, hydrolyzed it to ADO. Only CD4(+) CD39(+) T(reg) co-incubated with CD4(+) CD73(+) T cells, B cells or CD39(+) CD73(+) exosomes produced ADO. Thus, contact with membrane-tethered CD73 was sufficient for ADO production by CD4(+) CD39(+) T(reg). In microenvironments containing CD4(+) CD73(+) T cells, B cells or CD39(+) CD73(+) exosomes, CD73 is readily available to CD4(+) CD39(+) CD73(neg) T(reg) for the production of immunosuppressive ADO.

Preoperative fasting does not affect haemodynamic status: a prospective, non-inferiority, echocardiography study

BACKGROUND

The link between preoperative fasting and hypovolaemia remains unclear. We tested the hypothesis that preoperative fasting does not significantly increase the proportion of patients with hypovolaemia according to transthoracic echocardiography (TTE) criteria.

METHODS

Patients of ASA status I-III and without bowel preparation were included in a non-inferiority, prospective, single-centre trial. Patients underwent passive leg raising (PLR) test and TTE at admission (Day 0) and after 8 h fasting (Day 1). The primary hypothesis was that an 8 h preoperative fasting does not increase the proportion (margin=5%) of patients with a positive PLR test ('functional approach'). The secondary hypothesis was that echocardiographic filling pressures or stroke volume (margin 10%) are not affected by preoperative fasting ('static approach').

RESULTS

One hundred patients were included and 98 analysed. After an 8 h fasting, the change in the proportion of responders to PLR was -6.1% [95% confidence interval (CI)=-16.0 to 3.8] of responders to PLR test on Day 0 when compared with Day 1. Because 95% CI was strictly inferior to 5%, there was no significant increase in the proportion of PLR responders on Day 1 when compared with Day 0. The 95% CI changes of static variables were always fewer than 10%, meaning that preoperative fasting induced significantly no relevant changes in static variables.

CONCLUSION

Preoperative fasting did not alter TTE dynamic and static preload indices in ASA I-III adult patients. These results suggest that preoperative fasting does not induce significant hypovolaemia. Clinical trial registration NCT 01258361.

[ICU patients and days of intensive care: A mathematical model optimizing the consequences of ICU unit function, intensive care and continual monitoring on incurred supplementary costs]

INTRODUCTION

"Critical Care Units" are intended to admit patients with multiple organ failure. The severity of patients admitted is variable. The aim of the study was to estimate the number of days that an optimum care organization could release, and therefore the additional admissions that would have been allowed. Estimates of earnings related to the various supplements were carried out jointly.

METHODS

Reporting days associated or not with a resuscitation care during the year 2011 in an ICU of a university hospital (16 beds), optimized patient flow simulation, and computation of medical act inducing financial supplements.

RESULTS

Six hundred and fifty-seven patients (SAPS II from 0 to 110, 41% ventilated more than 48hours, mortality=26%) were admitted representing 5095days (occupancy rate=87%). Two hundred and twenty-two patients (34%) did not trigger supplement for resuscitation care for 415days in the unit. Four hundred and thirty-five patients have triggered this supplement representing 4680days, including 3035days with resuscitation care and 1645 (35% of days valued resuscitation, 32% of total days) without any. The entire year 2011 has generated earnings of 3,980,192€. Optimization of management would have allowed the admission of additional 235 to 295 patients and potential additional earnings from 524,735€ to 1,063,804€, depending on the occupancy rate chosen (80% or real 2011s) and the severity of discharged patients.

CONCLUSION

Optimization of the patients flow between "Critical Care", Intensive Care and Continuous Monitoring Units would increase the number of patients admitted in "Critical Care" Units without any financial loss related to supplements.

A verocytotoxin-producing E. coli outbreak with a surprisingly high risk of haemolytic uraemic syndrome, Denmark, September-October 2012

Denmark faced an outbreak of verocytotoxin-producing E. coli (VTEC) O157:H7 infections in autumn 2012. Thirteen cases were diagnosed of which eight had haemolytic uraemic syndrome (HUS). Epidemiological investigations suggested ground beef as the vehicle of the outbreak. The outbreak strain had a rare toxin gene subtype profile: eae, vtx1a and vtx2a, and a high proportion of HUS (62%) among cases, a finding previously linked with the outbreak subtype profile. Toxin subtyping can be useful to identify high risk VTEC strains.

Org-2766, an acth(4-9)-msh(4-9) analog, modulates vincristine-induced neurotoxicity in the snail lymnaea-stagnalis

In vincristine (VCR) chemotherapy the dose-limiting factor is neurotoxicity, a side-effect which probably is caused by the action of the drug on axonal microtubules. VCR transforms them into paracrystalline structures. ORG 2766, an ACTH(4-9)/MSH(4-9), analogue, might have protective properties against this toxicity, because of its potency to induce the formation of microtubules. Therefore, the effects were studied of co-treatment with VCR and ORG 2766 on paracrystals and on microtubules in axons of the cerebral commissure (CC) of the snail Lymnaea stagnalis. In vitro experiments were carried out, incubating cerebral ganglia including the CC, for various periods of time (5-25 h) in Ringer's solution, in ORG 2766 (10(-6) M), in VCR (10(-4) M), or in VCR+ORG 2766. Furthermore, the effects of VCR (5 h) were studied in CC, pre- and/or post-treated with ORG 2766 (10 h). In another experiment VCR was used at a concentration at which no paracrystals were formed (2x10(-6) M). In this experiment VCR-treatment (5, 15 h) was compared to pre treatment and pre- and post-treatment with ORG 2766 (10 h). The numbers of microtubules (per mu m(2) axoplasm) and paracrystals (number encountered along perpendicular axes of the CC) were counted and the size of the paracrystals was measured in cross-sections of the CC, using electron microscopy. Irrespective of the type of additional treatment, significant differences were not observed in the numbers of paracrystals (32+/-10) after VCR-treatment for 5 h. Between 5 and 10 h of incubation the number increased (to 55+/-21) and remained approximately at this level. The number of microtubules decreased during the first 5 h of VCR treatment from 128+/-16 (control) to 37+/-10, and decreased further 19+/-5 between 5 and 10 h of incubation. The size of the paracrystals of all groups treated for 5 h with either VCR or VCR+ORG 2766 were similar (x=1.7 mu m(2)) However, the paracrystals were significantly larger in all groups co-treated for longer periods (10, 15 or 20 h) with ORG 2766 (VCR: x=2.3-3.0 mu m(2); VCR+ORG 2766: x=3.0-3.4 mu m(2)). This indicates that after an initial period of formation of paracrystals, tubulin is added to the existing paracrystals. At the low VCR concentration studied no paracrystals were formed. However, the number of microtubules had decreased significantly (from 159+/-10 to 84+/-17 after 15 h treatment). Pre- as well as pre- and post-treatment with ORG 2766 resulted in microtubule numbers which were not different from control values, indicating the positive effect of ORG 2766. In the groups pre- and/or post-treated with the high concentration of ORG 2766 (especially in the pre-treated group), the remaining number of microtubules was higher than in those co-treated with VCR and ORG 2766, but lower than in the controls. Although translation of the present results into clinical terms is difficult, they suggest that pre-and/or post-treatment with ORG 2766 may have a benificial effect on VCR-induced neurotoxicity. This conclusion is based on the observation that when ORG 2766 is given before VCR administration or after VCR clearance, larger numbers of microtubules were found in the nervous tissue than after treatment with VCR alone.

Properties of wr2721 (ethiofos) as modulator of Cisplatin-induced neurotoxicity studied at the ultrastructural level in the pond snail lymnaea-stagnalis

Modulating effects of WR2721 were studied on cisplatin-induced histological and ultrastructural changes in the ganglia of the central nervous system of the pond snail Lymnaea stagnalis. The relevance of the study was indicated by showing histochemically that alkaline phosphatase, the enzyme converting WR2721 into the active drug WR1065, is present in the snail brain. Central nervous systems of the snail were either preincubated in 5 mM WR2721 or in snail Ringer for 1 h and then postincubated for 10 or 20 h in: (i) Ringer (control), (ii) WR2721 (5 mM), (iii) cisplatin (0.4 mM), or (iv) cisplatin (0.4 mM) plus WR2721 (5 mM). The following parameters were studied: (i) general morphology, (ii) chromatin (number and mean clump size per unit surface ama, clump size frequency distribution), (iii) nucleoli (ratio of granular/fibrillar areas, (iv), Golgi zones (mean surface area, area containing electron dense material), (v) secretory granules (number), (vi) lysosomes (number per unit surface area of cytoplasm). The focus was on two types of identified neuroendocrine cells. Incubation in Ringer alone (controls) caused slight inactivation of the cells between 10 and 20 h of incubation (e.g. relative decrease of the granular part of the nucleoli). WR2721 alone had comparable effects on the tissue. In addition, in this group, a reduction in the electron dense material of the Golgi zones was observed. No major differences in number of secretory granules were observed in any of the groups. Treatment with cisplatin alone for 20 h caused a disappearance of the orange colour of the ganglia, swelling of axons and distension of intercellular spaces. Such changes were not observed in the group treated with cisplatin plus WR2721 or any of the other experimental groups. Both cisplatin alone and cisplatin plus WR2721 caused an increase in the number of chromatin clumps and a decrease in the mean chromatin clump size after 10 and 20 h of incubation. With regard to these parameters no differences were observed between the two groups. The chromatin clump size distribution curves of both groups were significantly different from the curve of the controls. Compared to that of the cisplatin group, the curve of the cisplatin plus WR2721 group, especially after 10 h, had shifted in the direction of that of the controls. Treatment with cisplatin alone induced drastic changes in nucleolar morphology. After 20 h of incubation the nucleoli had transformed into homogeneous dense structures. After 10 h of incubation in cisplatin plus WR2721 nucleoli still had a normal appearance. After 20 h those of the co-treated group had also become electron dense and appeared to contain numerous dark dots. Cisplatin caused a significant decrease in the extent of the Golgi zones. Co-treatment with WR2721 prevented this decrease to a certain degree. In both groups the electron dense material had disappeared from the Golgi zones. Furthermore, cisplatin alone induced an increase in the number of lysosomes. This increase was slightly (but not significantly) prevented by co-treatment with WR2721. The observations on the snail neurons show that WR2721 at the concentration studied induced only minor morphological changes. The drug modulates to some extent the pathological changes caused by cisplatin. The results support clinical data indicating that cisplatin-induced neurotoxicity is reduced by WR2721.

[Reliability of the pulse contour analysis for cardiac output measurement for assessing the fluid responsiveness]

BACKGROUND

The cardiac output (CO) is classically measured in intensive care unit patients. pulse contour (PC) method allows monitoring of CO.

OBJECTIVE

The aim of the present study was to assess the ability of PC to assess the fluid responsiveness defined as an increase in CO more than or equal to 15% after 500 mL hydroxyethyl starch over 20 minutes.

PATIENTS AND METHODS

In this observational prospective study, patients in shock in whom a PC method was inserted were included. CO was measure using the PC and thermodilution methods before and after a fluid challenge indicated by the physician. The correlation coefficient was measured, the diagram of Bland and Altman was built and the percentage of error (Critchley and Critchley method) was calculated. The ability of PC to diagnose fluid responsiveness was assessed using a receiver operating characteristics (ROC) curve.

RESULTS

Sixty-two fluid challenges were performed in 37 included patients. After fluid challenge, r(2) was 0.05 (P<0.01), the bias between PC and thermodilution was 0.3 ± 1.2L/min and the percentage of error was 36%. The area of the ROC curve was 0.601 [0.468-0.723].

CONCLUSION

In ICU patients with shock, PC cannot replace thermodilution to diagnose fluid responsiveness.