Intravenous lipid emulsion interference in coagulation testing: an ex vivo analysis.

INTRODUCTION: Intravenous lipid emulsion is used in the rescue treatment of certain poisonings. A complication is interference with laboratory analyses. The aim of this study was to determine the impact of intravenous lipid emulsion on routine laboratory analysis of coagulation parameters ex vivo and determine if any of the analytical techniques remain reliable. METHODS: Samples were obtained from 19 healthy volunteers and divided in triplicate. One sample served as a control, and the other two were diluted to simulate the treatment of an average adult with Intralipid® 20 per cent Fresenius Kabi 100 mL (dilution-1) or 500 mL (dilution-2). Coagulation tests performed were prothrombin time, activated prothrombin time, D-dimer concentration and fibrinogen. Coagulation testing was performed by three techniques. Test-1 was performed on a Sysmex CN6000 analyzer. Test-2 was performed with a manual mechanical endpoint method using the semi-automated Stago KC4 Delta. Test-3 involved high-speed centrifugation before repeat testing on the Sysmex CN6000 analyzer. RESULTS: For test-1, only nine (47 per cent) samples in dilution-1 could be analyzed for coagulation tests, and no coagulation tests could be analyzed for dilution-2 because of lipaemia. For test-2 and test-3, all samples could be analyzed, and all results of both testing methods fell within the limits of the laboratory reference range. DISCUSSION: Difficulties in laboratory analysis of patients having received intravenous lipid emulsion are due to multiple factors. Most automated coagulation analyzers use optical measurements, which can be unreliable in the presence of a high intravenous lipid concentration. By altering the lipaemia in the testing solution using high-speed centrifugation or by using manual mechanical endpoint detection, we were able to obtain reliable results. These findings are limited by the use of an ex vivo method and healthy volunteers. CONCLUSIONS: This ex vivo model confirms that Intralipid® interferes with routine coagulation studies. It is important that clinicians are aware and inform their laboratories of its administration.

Paracetamol toxicity in mild overdose in combination with opioids: A retrospective observational study.

AIMS: Toxicity in paracetamol overdose with opioid co-ingestion is poorly understood. We compared outcomes in both paracetamol-only and paracetamol-opioid overdoses to determine whether toxicity differed significantly between the groups, and to assess the utility of the ratio of measured plasma paracetamol concentration relative to the 4-hour nomogram-adjusted level (APAPpl /APAPt ). METHODS: We conducted a retrospective observational study of all patients (n = 1159) presenting to 2 large UK hospitals between 2005 and 2013 with acute single-dose ingestion paracetamol overdose, with (n = 221) or without (n = 938) opioid co-ingestion. Adverse outcomes included biomarkers of hepatotoxicity and the need for extended treatment. Several outcomes were assessed in relation to the APAPpl /APAPt ratio. RESULTS: Median ingested dose of paracetamol was low in both groups (10 g). Statistical comparison of the median APAPpl /APAPt ratios showed a significant difference (0.65 vs. 0.56 for the paracetamol-only and paracetamol-opioid groups respectively, P = .0329). Although there was a trend towards a lower risk of predefined toxic outcomes with opioid co-ingestion, statistical analysis did not show a significant difference, with outcomes for the paracetamol-only and paracetamol-opioid groups including the following: alanine transaminase >2× upper limit of normal, 7.7 vs. 5.7% (P = .6480); alanine transaminase >1000 IU/L, 2.4 vs. 0% (P = .2145); international normalised ratio > 1.3, 8.6 vs. 4.4% (P = .2774); and transfer to tertiary liver unit, 0.2 vs. 0% (P nonsignificant). CONCLUSION: Our study does not support a change in current clinical practise beyond standard testing at 4 hours or longer post ingestion for mixed low dose paracetamol-opioid overdose.

Gadolinium Concentrations in Biological Matrices From Patients Exposed to Gadolinium-Based Contrast Agents.

OBJECTIVES: There is increasing evidence that Gd may be retained within the skin, bones, and solid organs in patients with normal renal function after exposure to Gd-based contrast agents (GBCAs). Here we present clinical data from 19 patients who requested referral to our clinical toxicology service for assessment of potential "Gd toxicity." MATERIALS AND METHODS: Patients had undergone a median of 2 (interquartile range [IQR], 1-5) exposures to GBCAs and were reviewed at a median of 5 months (IQR, 2-8 months) after the last GBCA exposure. Patients had a clinical assessment by a clinical toxicologist, and biological samples were taken in 17 patients (89.5%). Gd concentrations were measured in these samples using inductively coupled plasma mass spectrometry. RESULTS: All patients had significant comorbidities, and after an extensive clinical review, none of the reported symptoms were considered likely to be related to "Gd toxicity." Whole blood, plasma, and urine samples had detectable Gd concentrations in 69.2%, 78.6%, and 95.2% of samples, respectively. Median (IQR) concentrations of Gd were as follows: whole blood, 0.013 ng/mL (IQR, limit of detection [LOD]-0.884 ng/mL); plasma, 0.012 ng/mL (IQR, LOD-0.046 ng/mL); and spot urine, 0.304 µg/g creatinine (IQR, 0.070-3.702 µg/g creatinine). There were positive correlations between whole blood and plasma (P = 0.0024, r = 0.84), whole blood and urine (P = 0.0018, r = 0.82), and plasma and urine (P = 0.0001, r = 0.89) Gd concentrations. There was a negative correlation between Gd concentrations and the period after exposure for whole blood (P = 0.0028, r = -0.80), plasma (P = 0.0004, r = -0.86), and urine (P < 0.0001, r = -0.91). CONCLUSIONS: We identified detectable Gd concentrations in biological matrices from all patients reporting exposure to GBCAs who were reviewed in our clinical toxicology outpatient clinic with concerns regarding potential "Gd toxicity"; however, there were no clinical features of toxicity present in this cohort. Further research is required to explore the pharmacokinetics and pharmacodynamics of GBCAs in patients with normal renal function and to determine the clinical significance of these detectable Gd concentrations.

Acute toxicity related to misuse (nonmedical use) of tramadol: Experience of the European Drug Emergencies Network Plus.

Following the development of the tramadol crisis currently affecting countries in the Middle East, and Africa, there has been increasing international interest in the regulation of tramadol. This study investigates the misuse of tramadol in patients presenting to emergency departments across Europe. Data from 32 emergency departments in 21 countries were extracted from the Euro-DEN Plus database for the 4-year period from 1 January 2014 to 31 December 2017. Of the reported 24,957 emergency department presentations, tramadol misuse was reported in 105 (0.4% presentations). Tramadol misuse was most common in Bratislava (Slovakia; n = 11, 7.5% of all presentations to this centre), Riga (Latvia; n = 4, 4.9%) and Munich (Germany; n = 17, 2.9%). On arrival, 14 (13.3%) of presentations were in coma/Glasgow coma score ≤ 8 and 9 of these had a respiratory rate <12 breaths/min. These presentations potentially pose a significant burden on emergency departments with a large proportion requiring admission to hospital for ongoing care.

Establishing Reference Intervals for Gadolinium Concentrations in Blood, Plasma, and Urine in Individuals Not Previously Exposed to Gadolinium-Based Contrast Agents.

OBJECTIVES: Over the recent years, there have been increasing concerns that exposure to gadolinium-based contrast agents (GBCAs) may be associated with retention of Gd within the skin, bones, and solid organs in patients with normal renal function, although the clinical implications of this deposition remain to be established. There are no published data available to guide the development of reference intervals for Gd concentrations in biological samples from healthy people. The aims of this study were to (1) determine whether healthy individuals who have not received GBCAs have detectable concentrations of Gd in their blood and urine, and (2) to develop a reference range for Gd concentrations in blood and spot urine samples for healthy individuals. MATERIALS AND METHODS: Whole blood, plasma, and spot urine samples were taken from 120 healthy volunteers with estimated glomerular filtration rate 70 mL/min per 1.73 m or greater. Gd concentrations were measured in these samples using inductively coupled plasma mass-spectrometry. The reference intervals for Gd concentrations in whole blood, plasma, and urine were estimated as the 2.5th percentile and the upper reference limit as the 97.5th percentile. RESULTS: Ten (8.33%) of the 120 subjects had detectable concentrations of Gd in their whole blood (n = 5) or spot urine (n = 5) samples; no subjects had detectable concentrations of Gd in their plasma samples. Our proposed reference intervals for Gd are as follows: whole blood, <0.008 ng/mL or <0.050 nmol/L; plasma, <0.009 ng/mL or <0.057 nmol/L; spot urine, <0.036 µg/g or <0.0250 nmol/mmol. CONCLUSIONS: The results of this study provide reference intervals for whole blood, plasma, and urine Gd concentrations in healthy subjects who have not previously received GBCAs and will assist clinicians in assessing patients who have concerns regarding potential Gd retention postexposure and help guide further clinical studies to explore the pharmacokinetics of GBCAs in patients with normal renal function.

Evaluation of long-term detection trends of new psychoactive substances in pooled urine from city street portable urinals (London, UK).

AIMS: To evaluate the long-term trends of new psychoactive substance (NPS) detection in pooled urine samples collected across a city centre. METHODS: Pooled urine samples from portable stand-alone urinals were collected on a monthly basis over 5.5 years (July 2013-December 2018) across a city centre. These were analysed using a high-performance liquid chromatography system, interfaced to a high-resolution accurate mass spectrometer. Data were processed against a database containing over 2000 drugs/metabolites including over 800 NPS. RESULTS: In total, 44 NPS were detected with variation over time including cathinones (15, 34.1%), synthetic cannabinoids (8, 18.2%) and 21 (47.7%) other NPS. Since the introduction of the UK Psychoactive Substances Act (May 2016) cathinone detection has decreased with minimal detection over the last 4 months of the study. Synthetic cannabinoids were not detected on a regular basis until July 2016 with a subsequent variable detection frequency. There was a consistent, low level detection frequency of all other NPS throughout the study, but which appears to have increased alongside the decrease in cathinone detection. CONCLUSION: Pooled urine analysis of samples taken from portable urinals in a city centre can be used as an effective monitoring tool to determine long-term trends in the use of NPS. The results of this study demonstrate the impact of the Psychoactive Substances Act and reflect the findings of population surveys and clinical studies. Triangulation of these data with other data sources will enable greater insight into the NPS phenomenon.

Gadolinium-based contrast agents - what is the evidence for 'gadolinium deposition disease' and the use of chelation therapy?

Introduction: Gadolinium-based contrast agents are widely used for magnetic resonance imaging and, until recently, had been generally considered to have an excellent safety profile in patients with normal renal function. Nephrogenic systemic fibrosis is a well-established disease process involving fibrosis of the skin and internal organs seen in some patients with severely impaired renal function following exposure to these agents. Following reports that individuals with normal renal function may experience gadolinium deposition within brain and bone tissue, the term "gadolinium deposition disease" has been proposed and the use of chelating agents has been recommended to treat this "disease".Objectives: This review will address the clinical evidence for "gadolinium deposition disease" and discuss whether chelation therapy is appropriate for individuals who believe they have this condition.Methods: Electronic databases (PUBMED, Ovid MEDLINE and EMBASE) were searched up to 1st October 2019 for all studies evaluating clinical signs or symptoms related to potential gadolinium toxicity post-gadolinium-based contrast agent exposure in subjects with normal renal function, or papers evaluating the potential chelation of gadolinium in humans.Does "gadolinium deposition disease" exist as a novel condition? We identified four clinical studies relating to "gadolinium deposition disease", including one that included some discussion of the use of chelation therapy. Two of the clinical studies presented data from anonymous online surveys that recruited participants from support forums for people who self-identified as having gadolinium-based contrast agent-induced toxicity, with questions focussing on their reported symptoms and signs. The published literature to date has demonstrated that gadolinium deposition within the brain primarily occurs within the dentate nucleus and globus pallidus. These patients did not complain of movement disorders, but instead reported generalised sensory symptoms, which would not be expected to occur with pathology in these areas of the brain. There was considerable selection bias and a lack of available clinical information to exclude alternative medical diagnoses for these series, thus rendering the results difficult to interpret.Role of chelation therapy in patients exposed to gadolinium-based contrast agent: One study reported data from 25 patients who were diagnosed with "gadolinium deposition disease" according to unspecified criteria and were treated with intravenous calcium or zinc trisodium pentetate. The authors reported an increase in urine gadolinium concentrations following administration of the chelating agents, which they attributed to re-chelation of gadolinium from tissue deposits, however, there are insufficient data to be able to substantiate this.Conclusion: There is currently no published information from well-designed clinical studies that support a link between gadolinium deposition and the development of clinical sequelae in patients with normal renal function. Clinicians should exercise caution when considering whether or not gadolinium is of relevance in patients reporting symptoms after administration of gadolinium-based contrast agents. The inappropriate use of chelation therapy in patients with no clear evidence-based indication for their use potentially increases the risk of clinically significant harm to these patients from the adverse effects of chelation. Further research and well-designed clinical and epidemiological surveillance is needed to determine whether there are toxicological risks related to gadolinium exposure from the use of gadolinium-based contrast agents in patients with normal renal function.

An evaluation of the role of mixing techniques in the observed variation in acetylcysteine infusion concentrations.

Intravenous acetylcysteine is commonly prescribed as a course of three infusions for the management of paracetamol poisoning. Previous studies have demonstrated large variation in administered doses of intravenous acetylcysteine, which has been attributed to numerous factors, including inadequate mixing of infusion bags. The aim of this study was to determine whether the amount of mixing of infusion bags contributes significantly to this variation. Using acetylcysteine doses for a 60-69 kg patient, we added the appropriate volume of acetylcysteine to 5% glucose and subsequently inverted the infusion bags 0-5 times to mix the solutions. Infusion bags were then run through using an infusion pump and acetylcysteine concentrations measured at the beginning and end of the infusions. We found no significant difference between the beginning and end concentrations of acetylcysteine regardless of whether bags were mixed or not; infusion 1 (150 mg kg-1 ) showed beginning and end concentrations of 44.61 and 42.48 mg ml-1 respectively after 0 mixes, whilst beginning and end concentrations were 44.45 and 44.58 mg ml-1 respectively after five mixes. The same trend was observed for infusions 2 and 3. This confirmed that mixing does not play a substantial role in variation of drug concentrations; these are likely to be caused by an accumulation of small errors in infusion preparation.

Gadolinium deposition and the potential for toxicological sequelae - A literature review of issues surrounding gadolinium-based contrast agents.

Every year, approximately 30 million magnetic resonance imaging scans are enhanced with gadolinium-based contrast agents (GBCAs) worldwide. Although the development of nephrogenic systemic fibrosis in patients with renal impairment is well-documented, over recent years it has become apparent that exposure to GBCAs can potentially result in gadolinium deposition within human bone and brain tissue even in the presence of normal renal function. This review will address some of the controversies surrounding the safety of GBCA administration based on evidence from in vivo experiments, animal studies and clinical studies. We additionally evaluate the potential risk of toxicity from exposure to gadolinium in light of new guidance published by the US Food and Drug Administration and the European Medicines Agency, and discuss whether gadolinium deposition disease exists as a new diagnosis.

The effect of aspirin on circulating netrin-1 levels in humans is dependent on the inflammatory status of the vascular endothelium.

In atherosclerotic animal models, the cyclo-oxygenase (COX)-inhibitor aspirin counteracts downregulation of endothelial-derived netrin-1, thus reducing arterial inflammation. We here explored the effect of aspirin on netrin-1 in healthy subjects undergoing influenza immunisation, which is an established experimental model of inflammation-related endothelial dysfunction. Our data showed that netrin-1 undergoes reduction (-29.25% from baseline; p=0.0017) in the presence of endothelial activation (VCAM-1 rose by 9.98% 2-days post-vaccination; p=0.0022). Aspirin counteracted vaccine-induced endothelial activation and reduction of netrin-1 in a dose-dependent manner (-3.06% and -17.03% from baseline at a dose of 300mg and 75mg respectively; p=0.0465 and p>0.05 vs untreated). Clopidogrel, which was used as a comparator due to its similar anti-platelet activity, also reduced endothelial activation but, unlike aspirin, enhanced netrin-1 levels (+20.96% from baseline; p=0.0033 vs untreated). A correlation analysis incorporating cytokines, hs-CRP, VCAM-1, TXB2 and PGE2, showed that changes in netrin-1 were directly related to PGE2 variations only (r=0.6103; p=0.0002). In a separate population of 40 healthy unimmunised volunteers, 28-day treatment with aspirin 300mg reduced netrin-1 (-18.76% from baseline; p=0.0012) without affecting endothelial markers or hs-CRP; as expected, aspirin suppressed TXB2 and PGE2. Netrin-1 and PGE2 levels were directly related (r=0.358; p=0.0015), but other parameters including TXB2, hs-CRP and endothelial markers, were not. In conclusion, aspirin counteracts downregulation of netrin-1 following endothelial dysfunction due to its anti-inflammatory effect on the activated endothelium. However, inhibition of COX-dependent prostanoids negatively modulates netrin-1 synthesis in healthy subjects, and this could give rise to aspirin-dependent reduction in netrin-1 under steady state conditions.

Antiplatelet Therapy in Acute Coronary Syndrome.

Antiplatelet agents have for decades been used to improve outcomes in patients with acute coronary syndromes and have become increasingly valued, not only for their antithrombotic properties but also for their anti-inflammatory effects. The drug class continues to evolve as novel agents with increasingly efficacious antiplatelet actions are identified. This review will discuss antiplatelet agents, including aspirin, the P2Y12 receptor antagonists and the glycoprotein IIb/IIIa inhibitors, that are currently used to treat patients with unstable angina and myocardial infarction, focusing on their pharmacological properties and the clinical evidence supporting their use.

Traditional Chinese medicines in the management of cardiovascular diseases: a comprehensive systematic review.

AIMS: The aim was to perform a systematic review of the efficacy of traditional Chinese medicines (TCM) in cardiovascular disease. METHODS: Electronic databases were searched up to 11 November 2015 for all randomized-controlled trials evaluating the effect of TCM in hypertension, ischaemic stroke, heart failure, coronary heart disease and type 2 diabetes mellitus. Pooled odds ratios (ORs) were calculated using a fixed-effects model. RESULTS: Four hypertension studies were eligible for statistical analysis and included 133 patients receiving TCM and 130 control patients. There were significant reductions in systolic blood pressure in patients receiving TCM, comparable to results achieved with pharmaceutical medicines. An OR of 3.781 (95% confidence interval 2.392, 5.977; P = 0.000) was observed for the anti-hypertensive effect of TCM. Significant heterogeneity was present (P = 0.011), with a tendency towards publication bias that did not reach significance (P = 0.05275). Outcome measures for other cardiovascular diseases were inconsistent. CONCLUSIONS: Certain TCM compounds appear to have significant anti-hypertensive effects, and although some are associated in some studies with improved outcomes in coronary heart disease, heart failure and type 2 diabetes mellitus, the data are inconsistent and will require large-scale randomized-controlled trials to allow full evaluation of any potential therapeutic benefit in these areas.

Anti-platelet drugs attenuate the expansion of circulating CD14highCD16+ monocytes under pro-inflammatory conditions.

AIMS: Levels of circulating CD14(high)CD16(+) monocytes increase in atherosclerotic patients and are predictive of future cardiovascular events. Platelet activation has been identified as a crucial determinant in the acquisition of a CD16(+) phenotype by classical CD14(high)CD16(-) cells. We tested the hypothesis that anti-platelet drugs modulate the phenotype of circulating monocytes. METHODS AND RESULTS: Sixty healthy subjects undergoing influenza immunization were randomly assigned to either no treatment or anti-platelet therapy, namely aspirin 300 mg or 75 mg daily, or clopidogrel (300 mg loading dose followed by 75 mg), for 48 h post-immunization (n = 15/group). Monocyte subsets, high-sensitivity C-reactive protein, pro-inflammatory cytokines, and P-selectin were measured at baseline and post-immunization. The CD14(high)CD16(+) monocyte cell count rose by 67.3% [interquartile range (IQR): 35.7/169.2; P = 0.0002 vs. baseline] in untreated participants. All anti-platelet regimes counteracted expansion of this monocytic subpopulation. Although no statistical differences were noted among the three treatments, aspirin 300 mg was the most efficacious compared with the untreated group (-12.5% change from baseline; IQR: -28.7/18.31; P = 0.001 vs. untreated). Similarly, the rise in P-selectin (17%; IQR: -5.0/39.7; P = 0.03 vs. baseline) observed in untreated participants was abolished by all treatments, with aspirin 300 mg exerting the strongest effect (-30.7%; IQR: -58.4/-0.03; P = 0.007 vs. untreated). Changes in P-selectin levels directly correlated with changes in CD14(high)CD16(+) cell count (r = 0.5; P = 0.0002). There was a similar increase among groups in high-sensitivity C-reactive protein (P < 0.03 vs. baseline levels). CONCLUSIONS: Anti-platelet drugs exert an immunomodulatory action by counteracting CD14(high)CD16(+) monocyte increase under pro-inflammatory conditions, with this effect being dependent on the amplitude of P-selectin reduction.

Netrin-1 as a novel therapeutic target in cardiovascular disease: to activate or inhibit?

Netrins are a family of laminin-like proteins, which were initially identified for their role in embryonic axonal guidance. Over recent years, it has become apparent that netrin-1 may additionally be involved in the underlying pathology of several multisystem diseases, making it an attractive potential therapeutic target. It is involved in postnatal angiogenesis, particularly in the context of an ischaemic insult, although there are conflicting reports as to whether netrin-1 acts in a pro- or anti-angiogenic capacity. In atherosclerosis, opposing effects have similarly been reported on plaque progression, due to the ability of netrin-1 to inhibit both macrophage egress from and monocyte ingress into lesions. Netrin-1 has also been shown to exert a cardioprotective action in the context of ischaemia-reperfusion injury following myocardial infarction. Moreover, urinary netrin-1 levels rise in response to acute kidney injury and at a faster rate than traditional markers of renal impairment, highlighting a potential clinical role for netrin-1 as a biomarker of renal function. The increased urinary excretion of netrin-1 during kidney disease is paralleled by a down-regulation of its plasma levels, with potential implications at a systemic level. In summary, the role of netrin-1 in cardiovascular disease is an emerging area of research requiring further in-depth study to elucidate its mechanism of action and potential as a therapeutic target, especially in view of its seemingly contradictory actions in certain physiological pathways which serve to highlight its manifold and often opposite effects in numerous physiological and pathophysiological processes.

Modernising morning report: innovation in teaching and learning.

BACKGROUND: Over recent years there has been a shift in undergraduate medical education, from predominantly passive, didactic teaching methods to facilitating learning by focusing on the management of common scenarios, through the means of problem- and case-based learning. CONTEXT: Case-based learning and peer-led teaching are often overlooked at postgraduate level, despite the continuing demonstrated success of these methods in fostering independent reasoning and problem-solving skills that are vital for newly qualified doctors to develop. When trying to strike a balance between educational needs and service provision, it is essential to identify and implement efficient, effective approaches to optimise learning opportunities. INNOVATION: We have adapted the pre-existing framework of the American 'Morning Report' to suit the needs of today's junior doctors, creating a system of providing case-based learning paired with peer-led teaching. IMPLICATIONS: We evaluated the educational model through a focus group session, and found that our Morning Report was a unique environment where junior doctors feel comfortable engaging with group case-based teaching, with the support and encouragement of senior consultants, reinforced with online case summaries and blog resources.