Extracorporeal treatment of intoxications:

Use of extracorporeal therapies to treat life-threatening intoxications

Toxic ingestions are a significant cause of pediatric morbidity and mortality, with some requiring extracorporeal removal for therapy. Given the emergent and life-threatening nature of such scenarios, it is paramount that clinicians caring for intoxicated children be familiar with the subject. This review summarizes the following: (a) the properties of a substance which lend it amenable to removal; (b) the current extracorporeal treatment modalities available for such removal (of which hemodialysis is typically the ideal choice); (c) an introduction and framework to use a quick reference guide from the Extrip organization, which has a website available to guide clinicians' rapid decisions; and (d) new membranes/approaches that may optimize clearance of certain intoxications.

Application of Hemoperfusion in the Treatment of Acute Poisoning

Rescue of acute poisoning is a race against time, and it is particularly important to remove toxic substances in time. Traditional methods include gastric lavage, promoting elimination, chelating agents, and other treatments. Hemoperfusion is a common blood purification technique. In the clinical practice of acute poisoning, hemoperfusion can directly remove toxic substances through its unique adsorption effect, showing its excellent efficacy. This paper reviews the experience of hemoperfusion in the treatment of various drug overdoses, pesticides, biological toxins, and industrial poisons, even drug addiction. It is hoped to provide a reference for clinicians in acute poisoning rescue.

Experimental Demonstration of Compact Polymer Mass Transfer Device Manufactured by Additive Manufacturing with Hydrogel Integration to Bio-Mimic the Liver Functions

In this paper, we designed and demonstrated a stimuli-responsive hydrogel that mimics the mass diffusion function of the liver. We have controlled the release mechanism using temperature and pH variations. Additive manufacturing technology was used to fabricate the device with nylon (PA-12), using selective laser sintering (SLS). The device has two compartment sections: the lower section handles the thermal management, and feeds temperature-regulated water into the mass transfer section of the upper compartment. The upper chamber has a two-layered serpentine concentric tube; the inner tube carries the temperature-regulated water to the hydrogel using the given pores. Here, the hydrogel is present in order to facilitate the release of the loaded methylene blue (MB) into the fluid. By adjusting the fluid’s pH, flow rate, and temperature, the deswelling properties of the hydrogel were examined. The weight of the hydrogel was maximum at 10 mL/min and decreased by 25.29% to 10.12 g for the flow rate of 50 mL/min. The cumulative MB release at 30 °C increased to 47% for the lower flow rate of 10 mL/min, and the cumulative release at 40 °C climbed to 55%, which is 44.7% more than at 30 °C. The MB release rates considerably increased when the pH dropped from 12 to 8, showing that the lower pH had a major impact on the release of MB from the hydrogel. Only 19% of the MB was released at pH 12 after 50 min, and after that, the release rate remained nearly constant. At higher fluid temperatures, the hydrogels lost approximately 80% of their water in just 20 min, compared to a loss of 50% of their water at room temperature. The outcomes of this study may contribute to further developments in artificial organ design.

The Efficacy of Albumin Dialysis in the Treatment of Severe Cholestatic Drug-Induced Liver Injury

Drug-induced liver injury (DILI) is a significant cause of acute liver injury and can present as cholestatic injury with or without associated hepatitis. Although most patients with DILI recover with supportive care, some can develop severe refractory cholestasis that impairs recovery of hepatic function, with subsequent progression to acute or chronic liver failure. Current pharmacotherapy and extracorporeal therapies such as hemodialysis have limited benefit. Albumin dialysis is an emerging strategy in the extracorporeal treatment of intoxications caused by protein bound drugs and can be used for the removal of albumin bound bilirubin and bile acids.

Extracorporeal blood purification in acutely intoxicated veterinary patients: A multicenter retrospective study (2011-2018): 54 cases

OBJECTIVE

To investigate the clinical outcome and complications associated with extracorporeal blood purification (EBP) using either hemodialysis (HD), hemodialysis and hemoperfusion (HD + HP), or therapeutic plasma exchange (TPE) for the management of acute toxin ingestion in small animals.

DESIGN

Retrospective, multicenter study from January 2011 to July 2018.

SETTING

One university teaching hospital and one private specialty hospital.

ANIMALS

Fifty-one dogs and 3 cats with a history of acute toxin exposure that could lead to severe morbidity and mortality, managed with different EBP techniques.

MAIN RESULTS

Nonsteroidal anti-inflammatory drugs (38/54, 52%), baclofen (8/54, 15%), and ethylene glycol (7/54, 13%) were the most common toxicities treated with EBP. Membrane-based TPE was used most commonly (22/54, 40.7%), followed by HD (17/54, 31.5%) and then HD + HP (15/54, 27.8%). There was an 83.3% (45/54) overall survival, with 88.9% (8/9) of nonsurvivors having clinical signs prior to therapy. One third (18/54) of the patients never developed clinical signs of toxicity. Treatment complications occurred in 44.4% (24/54) of the animals, although only 18.5% (10/54) of these complications, such as mild hypotension, thrombocytopenia secondary to the HP cartridge, facial swelling after plasma transfusion for TPE, bleeding from catheter size secondary to heparinization, or clotting of the system, could be attributed to the EBP treatment. None of the nonsurvivors died because of EBP complications.

CONCLUSIONS

Early initiation of EBP therapy might be considered as an alternative route of decontamination in severe acute toxicities with high potential for significant morbidity and mortality. The survival rate in small animals undergoing EBP is high despite exposure to potential lethal doses of toxins, and survival appears to be more likely if clinical signs of toxicity are not present at the time of EBP. Continued research is warranted with randomized controlled clinical trials to further evaluate the clinical efficacy and benefit of EBP.

Therapeutic nanoreactors for detoxification of xenobiotics: Concepts, challenges and biotechnological trends with special emphasis to organophosphate bioscavenging

The introduction of enzyme nanoreactors in medicine is relatively new. However, this technology has already been experimentally successful in cancer treatments, struggle against toxicity of reactive oxygen species in inflammatory processes, detoxification of drugs and xenobiotics, and correction of metabolic and genetic defects by using encapsulated enzymes, acting in single or cascade reactions. Biomolecules, e.g. enzymes, antibodies, reactive proteins capable of inactivating toxicants in the body are called bioscavengers. In this review, we focus on enzyme-containing nanoreactors for in vivo detoxification of organophosphorous compounds (OP) to be used for prophylaxis and post-exposure treatment of OP poisoning. A particular attention is devoted to bioscavenger-containing injectable nanoreactors operating in the bloodstream. The nanoreactor concept implements single or multiple enzymes and cofactors co-encapsulated in polymeric semi-permeable nanocontainers. Thus, the detoxification processes take place in a confined space containing highly concentrated bioscavengers. The article deals with historical and theoretical backgrounds about enzymatic detoxification of OPs in nanoreactors, nanoreactor polymeric enveloppes, realizations and advantages over other approaches using bioscavengers.

Retrospective evaluation of the use of hemodialysis in dogs with suspected metaldehyde poisoning (2012-2017): 11 cases

OBJECTIVE

To evaluate dogs treated with hemodialysis for severe metaldehyde intoxication and to compare them with conventionally-managed patients.

DESIGN

Retrospective study (2012-2017).

SETTING

University teaching hospital.

ANIMALS

Data from 18 dogs with severe metaldehyde intoxication were analyzed. Eleven dogs were treated with intermittent hemodialysis and 7 managed conventionally.

INTERVENTIONS

None.

MEASUREMENT AND MAIN RESULTS

Metaldehyde poisoning was diagnosed based on clinical signs and toxicological analysis or presence of turquoise material in the gastrointestinal content. Clinical signs, additional treatments, dialysis prescription, duration of anesthesia and hospitalization, complications, and outcome were documented. Results were analyzed by t-test, Mann-Whitney U-test, and Chi-square test. P < 0.05 was considered significant. Dialysis was performed for median (range) 180 min (150-420 min) with median of 2.28 L/kg (1.66-4.48 L/kg) blood volume processed. In the hemodialysis group, anesthesia was discontinued at a median of 3.0 hours (1.5-6.7 h) after starting dialysis. The conventional-group received general anesthesia for a median of 17.5 hours (7.0-30.5 h). No further anticonvulsive treatment was necessary for the hemodialysis group. Time to hospital discharge was shorter in dialyzed dogs (median 18 h; 15-41 h) compared to conventionally treated dogs (median 89 h; 61-168 h; P = 0.0014). Aspiration pneumonia was reported in 5 conventionally treated dogs and none of the dialyzed dogs (P = 0.001). Five dialyzed dogs developed hematoma at the dialysis catheter site. One dog in each group was euthanized.

CONCLUSION

Hemodialysis significantly decreases the requirement for anesthesia and length of hospitalization in dogs with metaldehyde intoxication. Aspiration pneumonia occurred less often in dialyzed patients. Prospective studies are warranted to confirm the clinical utility of hemodialysis in dogs with metaldehyde poisoning.

Hemoadsorption Improves Survival of Rats Exposed to an Acutely Lethal Dose of Aflatoxin B1

Mycotoxins, such as aflatoxin B1 (AFB1), pose a serious threat as biological weapons due to their high toxicity, environmental stability, easy accessibility and lack of effective therapeutics. This study investigated if blood purification therapy with CytoSorb (CS) porous polymer beads could improve survival after a lethal aflatoxin dose (LD90). The effective treatment window and potential therapeutic mechanisms were also investigated. Sprague Dawley rats received a lethal dose of AFB1 (0.5-1.0 mg/kg) intravenously and hemoperfusion with a CS or Control device was initiated immediately, or after 30, 90, or 240-minute delays and conducted for 4 hours. The CS device removes AFB1 from circulation and significantly improves survival when initiated within 90 minutes of toxin administration. Treated subjects exhibited improved liver morphology and health scores. Changes in the levels of cytokines, leukocytes and platelets indicate a moderately-severe inflammatory response to acute toxin exposure. Quantitative proteomic analysis showed significant changes in the level of a broad spectrum of plasma proteins including serine protease/endopeptidase inhibitors, coagulation factors, complement proteins, carbonic anhydrases, and redox enzymes that ostensibly contribute to the therapeutic effect. Together, these results suggest that hemoadsorption with CS could be a viable countermeasure against acute mycotoxin exposure.

Phenytoin Toxicity Treatment with Haemodialysis in Epilepsy due to Glioblastoma Multiforme: Case Report and Review of the Literature

Phenytoin is one of the most commonly used anticonvulsants in the developing world, but lack of monitoring and concurrent medications can easily lead to toxicity. We report the case of a 35-year-old female on phenytoin for symptomatic epilepsy due to previously treated glioblastoma multiforme, who presented with status epilepticus 1 week after being treated for a urinary tract infection. She was loaded with phenytoin and levetiracetam as per emergency protocol but had a persistently low level of consciousness, and her preloading phenytoin level result came back in the toxic range. She was managed conservatively, but after 4 days with no change she was dialyzed and her level of consciousness improved within 24 h, allowing for safe discharge home shortly after. Our case illustrates the option of haemodialysis in phenytoin-toxic patients who do not improve with conservative measures or who may need urgent reduction due to potentially fatal complications of phenytoin toxicity.

Extracorporeal treatment in children with acute severe poisoning

Acute poisoning in children is a clinical emergency. Prompt and effective treatment is critical for life-threatening poisoning. Extracorporeal treatment (ECTR) is a practical option for enhancing the elimination of poisons.We conducted a retrospective observational study on 338 children with severe acute poisoning who received ECTR during hospitalization from January 2010 to December 2017. The poisonous substances, utilization of ECTR, adverse reactions to ECTR, and outcomes were recorded.The top 3 poisoning categories, in order of frequency, were found to be pesticides (57.99%), biotoxins (25.15%), and pharmaceuticals (14.20%). Paraquat (35.21%), an organic heterocyclic herbicide with high toxicity to humans, was the most common toxic substance. The main modalities of ECTR use were hemoperfusion (50.59%) and therapeutic plasma exchange (42.60%), followed by continuous renal replacement therapy (4.44%) and hemodialysis (1.18%). There were also 4 patients (1.18%) with a combination of ECTR performed. Adverse events of ECTR included errhysis and hematomas around the catheter exit site, oral cavity bleeding, allergic reactions, hypothermia, hypotension, and blood coagulation. The adverse reactions were mostly mild to moderate and were manageable. During the study period, there were 295 patients (87.28%) who were cured, 9 (2.66%) who experienced some improvement, and 34 (10.06%) who died.ECTR modalities were found to be clinically effective approaches to the treatment of poisoning by pesticides, biotoxins, and pharmaceuticals, indicating they are important modalities in toxicology and treatment, and are well tolerated by children.

Hemoperfusion leads to impairment in hemostasis and coagulation process in patients with acute pesticide intoxication

Hemoperfusion (HP) is one of the important treatment modalities in extracorporeal therapy for patients with acute intoxication. Its use has declined during the past 20 years despite its efficacy, because of its side effects, especially an increased risk of bleeding. Mechanisms of hemostasis impairment have not been clearly elucidated and studies demonstrating the mechanism are lacking. It is not clear which step of the hemostatic process is impaired during HP, and whether it leads to an increased risk of bleeding. We performed both in vivo and in vitro studies to elucidate the mechanism of impairment in the hemostatic process. In patients with acute pesticide intoxication who underwent HP, the platelet count decreased rapidly during the first 30 minutes from 242.4 ± 57.7 × 10³/μL to 184.8 ± 49.6 × 10³/μL, then gradually decreased even lower to 145.4 ± 61.2 × 10³/μL over time (p < 0.001). As markers of platelet activation, platelet distribution width increased continuously during HP from 41.98 ± 9.28% to 47.69 ± 11.18% (p < 0.05), however, mean platelet volume did not show significant change. In scanning electron microscopy, activated platelets adhered to modified charcoal were observed, and delayed closure time after HP in PFA-100 test suggested platelet dysfunction occurred during HP. To confirm these conflicting results, changes of glycoprotein expression on the platelet surface were evaluated when platelets were exposed to modified charcoal in vitro. Platelet expression of CD61, fibrinogen receptor, significantly decreased from 95.2 ± 0.9% to 73.9 ± 1.6%, while those expressing CD42b, von Willebrand factor receptor, did not show significant change. However, platelet expression of CD49b, collagen receptor, significantly increased from 24.6 ± 0.7% to 51.9 ± 2.3%. Thrombin-antithrombin complex, a marker for thrombin generation, appeared to decrease, however, it was not statistically significant. Fibrin degradation products and d-dimers, markers for fibrinolysis, increased significantly during HP. Taken together, our data suggests that hemoperfusion leads to impairment of platelet aggregation with incomplete platelet activation, which was associated with reduced thrombin generation, accompanied by increased fibrinolysis.

Extracorporeal Barbotage Detoxification of the Blood Plasma

We studied the efficiency of bubbling air as a method of detoxification of the blood plasma and its mixtures with plasma substitutes from CCl4. The efficiency of detoxification depended on the characteristics of the obtained foams: foam forming ability, frequency rate, dispersion, stability of a foam skeleton, syneresis, etc. A hardware-software complex for extracorporeal blood plasma detoxification was developed and the programs for the control and regulation of this process were tested. Physical and mathematical models of toxicant excretion from the body during extracorporal blood detoxification were proposed. Verification of the mathematical model demonstrates high correspondence between the theoretical and experimental data.

New paradigm for rapid achievement of appropriate therapy in special populations: coupling antibiotic dose optimization rapid microbiological methods

INTRODUCTION

Some special patient populations (e.g. critically ill, burns, hematological malignancy, post-major surgery, post-major trauma) have characteristics that lead to higher rates of failure and mortality associated with infection. Choice of effective antibiotics and optimized doses are challenging in these patients that are commonly infected by multidrug-resistant pathogens. Areas covered: A review of the importance of diagnosis and the place of newer microbiological methods (e.g. whole-genome sequencing) to ensure rapid transition from empiric to directed antibiotic therapy is provided. The effects of pathophysiological changes on antibiotic pharmacokinetics are also provided. Expert opinion: Product information dosing regimens do not address the pharmacokinetic alterations that can occur in special patient populations and increase the likelihood of therapeutic failure and the emergence of bacterial resistance. Altered dosing approaches, supplemented with the use of dosing software and therapeutic drug monitoring, may be needed to ensure optimal antibiotic exposure and better therapeutic outcomes in these patients with severe infection. Dose optimization needs to be coupled with advanced microbiological techniques that enable rapid microbiological identification and characterization of resistance mechanism to ensure that maximally effective directed therapy can be chosen.

A stepwise approach for the management of poisoning with extracorporeal treatments

The use of an extracorporeal treatment (ECTR) in a poisoned patient may be life-saving in a limited number of scenarios. The decision-processes surrounding the use of ECTR in poisoning is complex: most nephrologists are not trained to assess a poisoned patient while clinical toxicologists rarely prescribe ECTRs. Deciding on which ECTR is most appropriate for a poison requires a good understanding of the poison's physicochemical and pharmacokinetic properties. Further, a detailed understanding of the capabilities and limitations of the different ECTRs can be useful to select the most appropriate ECTR for a given clinical situation. This manuscript provides a stepwise approach to assess the usefulness of ECTRs in poisoning.

Recrudescent digoxin toxicity treated with plasma exchange: a case report and review of literature

A 53-year-old woman presented with digitalis toxicity caused by acute overdose that manifested as atrial tachycardia with block, sinus pauses, and competing AV junctional rhythm with atrial fibrillation. Patient admitted to overdosing with digoxin 15-20 h before presentation with intent to commit suicide. Serum digoxin level was 35.6 ng/ml and renal function was normal. Patient was treated with 1,040 mg of digoxin-specific antibody Fab fragment with prompt resolution of arrhythmias and restoration of sinus rhythm. Four hours after digoxin antibody administration, serum digoxin level declined to 0.2 ng/ml. Eighteen hours after treatment with Fab fragment, patient developed premature ventricular complexes, atrial tachycardia with and without atrioventricular block, and non-sustained ventricular tachycardia followed by ventricular fibrillation from which she was successfully resuscitated. Electrocardiogram showed no evidence of acute myocardial infarction, and emergent coronary angiogram did not reveal significant coronary artery disease. Repeat digoxin level was 20.4 ng/ml. A diagnosis of recrudescent digoxin toxicity was made and the patient was treated with one session of plasma exchange with resolution of arrhythmias. Immediately after plasma exchange, digoxin level decreased to 10.4 ng/ml, and after 10 h, the level further decreased to 6.6 ng/ml. The following day, digoxin level had decreased to 2.9 ng/ml. Our experience with this case would suggest that plasma exchange should be considered as a treatment modality for recrudescent digoxin toxicity.

Albumin-drug interaction and its clinical implication

BACKGROUND

Human serum albumin acts as a reservoir and transport protein for endogenous (e.g. fatty acids or bilirubin) and exogenous compounds (e.g. drugs or nutrients) in the blood. The binding of a drug to albumin is a major determinant of its pharmacokinetic and pharmacodynamic profile.

SCOPE OF REVIEW

The present review discusses recent findings regarding the nature of drug binding sites, drug-albumin binding in certain diseased states or in the presence of coadministered drugs, and the potential of utilizing albumin-drug interactions in clinical applications.

MAJOR CONCLUSIONS

Drug-albumin interactions appear to predominantly occur at one or two specific binding sites. The nature of these drug binding sites has been fundamentally investigated as to location, size, charge, hydrophobicity or changes that can occur under conditions such as the content of the endogenous substances in question. Such findings can be useful tools for the analysis of drug-drug interactions or protein binding in diseased states. A change in protein binding is not always a problem in terms of drug therapy, but it can be used to enhance the efficacy of therapeutic agents or to enhance the accumulation of radiopharmaceuticals to targets for diagnostic purposes. Furthermore, several extracorporeal dialysis procedures using albumin-containing dialysates have proven to be an effective tool for removing endogenous toxins or overdosed drugs from patients.

GENERAL SIGNIFICANCE

Recent findings related to albumin-drug interactions as described in this review are useful for providing safer and efficient therapies and diagnoses in clinical settings. This article is part of a Special Issue entitled Serum Albumin.

Prolonged Refractory Hypotension following Combined Amlodipine and Losartan Ingestion Responsive to Metaraminol

Introduction. Overdose with the calcium channel blocker amlodipine can cause profound hypotension that may be exacerbated by the concurrent ingestion of an angiotensin II receptor antagonist. Best management of such overdoses is uncertain although the use of hyperinsulinaemia-euglycaemia (HIE) has been recommended. Case report. We report a case of mixed amlodipine and losartan overdose in a 50-year-old lady. Severe hypotension was resistant to conventional vasopressors and high-dose insulin/euglycaemia, but did respond to a metaraminol infusion. Conclusion. A trial of metaraminol early in severe cases of calcium channel blocker and angiotensin II receptor antagonist toxicity may be of benefit, especially when conventional ionotropic treatment measures are failing.

Management of toxic ingestions with the use of renal replacement therapy

Although rare, renal replacement therapy (RRT) for the treatment of the metabolic, respiratory and hemodynamic complications of intoxications may be required. Understanding the natural clearance of the medications along with their volume of distribution, protein binding and molecular weight will help in understanding the benefit of commencing RRT. This information will aid in choosing the optimal forms of RRT in an urgent setting. Overdose of common pediatric medications are discussed with suggestions on the type of RRT within this educational review.

Toxicology today: what you need to know now

Clinicians are frequently confronted with toxicological emergencies and challenged with the task of correctly identifying the possible agents involved and providing appropriate treatments. In this review article, we describe the epidemiology of overdoses, provide a practical approach to the recognition and diagnosis of classic toxidromes, and discuss the initial management strategies that should be considered in all overdoses. In addition, we evaluate some of the most common agents involved in poisonings and present their respective treatments. Recognition of toxidromes with knowledge of indications for antidotes and their limitations for treating overdoses is crucial for the acute care of poisoned patients.

Management of the critically poisoned patient

BACKGROUND

Clinicians are often challenged to manage critically ill poison patients. The clinical effects encountered in poisoned patients are dependent on numerous variables, such as the dose, the length of exposure time, and the pre-existing health of the patient. The goal of this article is to introduce the basic concepts for evaluation of poisoned patients and review the appropriate management of such patients based on the currently available literature.

METHODS

An unsystematic review of the medical literature was performed and articles pertaining to human poisoning were obtained. The literature selected was based on the preference and clinical expertise of authors.

DISCUSSION

If a poisoning is recognized early and appropriate testing and supportive care is initiated rapidly, the majority of patient outcomes will be good. Judicious use of antidotes should be practiced and clinicians should clearly understand the indications and contraindications of antidotes prior to administration.

Acute liver impairment after sodium valproate overdose

Liver impairment is a recognised adverse effect of long-term sodium valproate treatment, but there are few reports concerning its occurrence after acute overdose. This report describes a 36-year-old woman who deliberately ingested 32 g of sodium valproate (Epilim). Serum valproate concentration was 4370 μmol/l (630 mg/l) at 4.3 h post-ingestion (therapeutic reference range: 300-600 μmol/l), and the elimination half-life was 14.1 h. Liver biochemistry tests were initially normal but gradually became impaired, and highest alanine aminotransferase (761 U/l) occurred 2.3 days after ingestion. Supportive measures alone were sufficient to allow recovery of liver function. This case indicates that sodium valproate overdose may cause acute hepatocellular injury, even in the absence of pre-existing liver disease.