The safety of high-dose insulin euglycaemia therapy in toxin-induced cardiac toxicity

Beta-blocker and calcium-channel blocker toxicity: current evidence on evaluation and management

Beta-blocker and calcium-channel blocker overdoses are associated with severe morbidity and mortality; therefore, it is important to recognize and appropriately treat individuals with toxicity. The most common clinical findings in toxicity are bradycardia and hypotension. In addition to supportive care and cardiac monitoring, specific treatment includes administration of calcium salts, vasopressors, and high-dose insulin euglycaemia treatment. Other advanced treatments (e.g. ECMO) may be indicated depending on the severity of toxicity and specific agents involved.

2023 American Heart Association Focused Update on the Management of Patients With Cardiac Arrest or Life-Threatening Toxicity Due to Poisoning: An Update to the American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care

In this focused update, the American Heart Association provides updated guidance for resuscitation of patients with cardiac arrest, respiratory arrest, and refractory shock due to poisoning. Based on structured evidence reviews, guidelines are provided for the treatment of critical poisoning from benzodiazepines, β-adrenergic receptor antagonists (also known as β-blockers), L-type calcium channel antagonists (commonly called calcium channel blockers), cocaine, cyanide, digoxin and related cardiac glycosides, local anesthetics, methemoglobinemia, opioids, organophosphates and carbamates, sodium channel antagonists (also called sodium channel blockers), and sympathomimetics. Recommendations are also provided for the use of venoarterial extracorporeal membrane oxygenation. These guidelines discuss the role of atropine, benzodiazepines, calcium, digoxin-specific immune antibody fragments, electrical pacing, flumazenil, glucagon, hemodialysis, hydroxocobalamin, hyperbaric oxygen, insulin, intravenous lipid emulsion, lidocaine, methylene blue, naloxone, pralidoxime, sodium bicarbonate, sodium nitrite, sodium thiosulfate, vasodilators, and vasopressors for the management of specific critical poisonings.

High-dose insulin should be used before vasopressors/inotropes in calcium-channel blocker toxicity

High-dose insulin (HDI) therapy with adapted glucose supplementation to maintain euglycaemia has been suggested to treat calcium-channel blocker (CCB) poisonings. Its underlying mechanisms of action are now well documented. We present a narrative review of the published experimental studies, case reports and experts' opinions to support the effectiveness and safety of HDI in the treatment of CCB poisoning. Our review strongly encourages the use of HDI as first-line therapy in CCB-poisoned patients in the presence of cardiovascular compromise, especially if cardiac function impairment has been diagnosed, before, but without delaying, the administration of vasopressors/inotropic drugs.

High dose insulin therapy for inotropic support during veno-arterial extracorporeal membrane oxygenation decannulation: A case report

RATIONALE

High-dose insulin (HDI) therapy has been used as inotropic support for toxin-induced cardiogenic shock, but literature suggests that it can also be used in non-toxin-induced cardiogenic shock states. Its use has not been reported in veno-arterial extracorporeal membrane oxygenation (VA-ECMO) decannulation.

PATIENT CONCERNS

A 56-year-old male presented with progressive dyspnea and lower extremity edema without any reported toxic ingestion.

DIAGNOSIS

After left heart catheterization, he was diagnosed with acute biventricular nonischemic cardiac failure that ultimately required VA-ECMO support for 8 days, after which decannulation was planned.

INTERVENTIONS

During decannulation, he was initiated on HDI therapy via a 1 U/kg regular insulin bolus with 25 g of dextrose and a 1 U/kg/hr insulin infusion.

OUTCOMES

During the decannulation, he was monitored with transesophageal echocardiography. Initially, left ventricular (LV) ejection fraction (EF) was estimated at 10% to 15%. Transesophageal echocardiography after HDI but prior to decannulation showed LVEF 30% to 40%. Transthoracic echocardiography 3.5 hours after HDI bolus and decannulation revealed normal LV systolic function; LVEF 50% to 55%.

LESSONS

While multiple interventions occurred during decannulation, HDI therapy may have assisted in transitioning off ECMO support, and HDI should be investigated as an adjunctive option in future decannulations and other non-toxin-induced cardiogenic shock states.

Evaluation of high-dose insulin/euglycemia therapy for suspected β-blocker or calcium channel blocker overdose following guideline implementation

PURPOSE

High-dose insulin/euglycemia (HDIE) is targeted therapy for β-blocker and calcium channel blocker overdose. A guideline using concentrated insulin infusions (20 units/mL), aggressive monitoring, and supportive recommendations was implemented. We sought to evaluate safety before and after HDIE guideline implementation and describe the patient population, insulin doses, supplemental dextrose, vasopressor use, hospital and intensive care unit (ICU) lengths of stay, and mortality.

METHODS

Retrospective review was performed of patients receiving HDIE before and after guideline implementation at an academic medical center and community hospital from March 2011 through December 2019. Information on patient and overdose demographics, ingestion data, vital signs, interventions, adverse events, and disposition was collected. Data are presented descriptively with comparisons using Mann-Whitney U analysis and Fisher's exact tests.

RESULTS

During the study period, 27 patients were treated with HDIE, 10 before guideline implementation (37%; mean [SD] initial insulin dose, 0.49 [0.35] units/kg/h; mean [SD] maximum insulin dose, 2.25 [3.29] units/kg/h; median [interquartile range] duration, 10 [5.5-18.75] hours) and 17 after guideline implementation (63%; mean [SD] initial insulin dose, 1.01 [0.34] units/kg/h; mean [SD] maximum insulin dose, 2.99 [5.05] unit/kg/h; median [interquartile range] duration, 16 [11.5-37] hours). Hypoglycemia, hypokalemia, and volume overload occurred in 80% vs 29% (P = 0.018), 40% vs 53% (P = 0.69), and 50% vs 65% (P = 0.69) of patients in the preguideline vs postguideline group, respectively. Most patients received an initial insulin bolus (85%; mean [SD], 70.3 [21.8] units, 0.9 [0.26] units/kg) and vasopressor infusion (85%). More postguideline patients received a dextrose infusion with a concentration of 20% or higher (93% vs 50%, P = 0.015). There were no differences in cardiac arrest, in-hospital mortality, or hospital or ICU length of stay between the groups.

CONCLUSION

Hypoglycemia was reduced using an HDIE guideline and concentrated insulin.

Variability in insulin pharmacokinetics following high-dose insulin therapy

INTRODUCTION

High dose insulin (HDI) therapy for cardiogenic shock from acute poisoning can be complicated by treatable hypoglycemia which persists following poisoning recovery. Glucose requirements post-HDI reflect supraphysiological insulin plasma concentration. A publication reported a patient treated with HDI with plasma insulin concentrations >1000 µU/mL and elimination half-life 10-18 h requiring intravenous glucose replacement for >5 days. We report two cases treated with HDI (Actrapid; soluble or regular insulin) with shorter elimination half-lives.

CASE REPORTS

A man ingesting diltiazem received HDI for approximately 60 h (maximum dose 10 U/kg/h) and supplemental intravenous dextrose for 44 h post-HDI. Post-HDI the maximum measured plasma insulin concentration was 6345 µU/mL and elimination half-life 5.5 h. A man ingesting propranolol received HDI for approximately 12 h (maximum dose 1.5 U/kg/h) and supplemental intravenous dextrose for 4 h post-HDI. Post-HDI the maximum measured plasma insulin concentration was 368 µU/mL and elimination half-life 2.2 h.

DISCUSSION

Markedly different insulin pharmacokinetics post-HDI is observed in two cases and a previously published report, and factors contributing to the interpatient differences are poorly defined. This pharmacokinetic variability impacts on the severity and duration of treatable hypoglycemia post-HDI. Analytical factors impacting on the measured plasma insulin concentrations include appropriate sample dilution and differing analytical specificity for the type of insulin.

Persistent Hyperinsulinemia Following High-Dose Insulin Therapy: A Case Report

INTRODUCTION

Overdoses of beta-adrenergic antagonists and calcium channel antagonists represent an uncommonly encountered but highly morbid clinical presentation. Potential therapies include fluids, calcium salts, vasopressors, intravenous lipid emulsion, methylene blue, and high-dose insulin. Although high-dose insulin is commonly used, the kinetics of insulin under these conditions are unknown.

CASE REPORT

We present a case of a 51-year-old male who sustained a life-threatening overdose after ingesting approximately 40 tablets of a mixture of amlodipine 5 mg and metoprolol tartrate 25 mg. Due to severe bradycardia and hypotension, he was started on high-dose insulin (HDI) therapy; this was augmented with epinephrine. Despite the degree of his initial shock state, he ultimately recovered, and HDI was discontinued. Insulin was infused for a total of approximately 37 hours, most of which was dosed at 10 U/kg/hour; following discontinuation, serial serum insulin levels were drawn and remained at supraphysiologic levels for at least 24 hours and well above reference range for multiple days thereafter.

CONCLUSION

The kinetics of insulin following discontinuation of high-dose insulin therapy are largely unknown, but supraphysiologic insulin levels persist for some time following therapy; this may allow for simple discontinuation rather than titration of insulin at the end of therapy. Dextrose replacement is frequently needed; although the duration is often difficult to predict, prolonged infusions may not be necessary.

High-Dose Insulin for Toxin Induced Cardiogenic Shock: Experience at a New High and Overview of the Evidence

BACKGROUND

High-dose insulin therapy is an effective treatment for cardiogenic shock caused by the overdose of particular medications. Other treatment options are usually of limited benefit. Consensus suggests that early initiation improves efficacy. No ceiling effect has been established at doses in the general range of 0.5-10 units/kg/hour.

CASE REPORT

A 79-year-old man presented in cardiogenic shock after an intentional overdose of numerous cardioactive medications 10 days after experiencing myocardial infarction. A high-dose insulin infusion was commenced. This was titrated up to a maximum of 20 units/kg/hour (1600 units/hour) and sustained for 32 h (61,334 units total). Minimal adverse events were seen despite this exceptional infusion rate (3 episodes of hypoglycemia and 2 episodes of hypokalemia). Concurrent catecholamine support was used, and cardiovascular function was maintained until all support was withdrawn 5 days after admission. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Emergency physicians are pivotal to the successful initiation/up-titration of high-dose insulin therapy. They must balance the potential for treatment failure with other treatment options, mitigate against adverse events in the initial phase of therapy, and coordinate care between other hospital specialties. This case shows that the relative safety and efficacy was extended to an infusion rate of 20 units/kg/hour, the highest recorded in the published literature. This information may help guide treatment of similar cases in the future.

Clinical Pearls in Medical Toxicology: Updates Ranging From Decontamination to Elimination

Such as any field of medicine, it is imperative to stay current with the latest advances and treatment modalities in toxicology. With the absence of rigorous randomized controlled trials, many updated guidelines are created by expert consensus and/or case reports and clinical experience. Over the past 10 years, there have been several changes in the management of drug overdoses in light of new data available. Although this is not a comprehensive review of all available antidotes, this article will focus on several important interventions including the use of gastrointestinal decontamination, hyperinsulinemic-euglycemic therapy, methylene blue, intravenous lipid emulsion, hemodialysis, and extracorporeal membrane oxygenation.

Metformin poisoning treated with high dose insulin dextrose therapy: a case series

Purpose

We describe the compassionate use of high dose insulin dextrose (HID) for life threatening metformin associated lactic acidosis (MALA) in four patients admitted to intensive care.

Methods

Patients presenting with refractory lactic acidosis believed to be secondary to metformin poisoning were included.High dose insulin dextrose at 0.5units/kg/hour was infused in 50% dextrose. Frequent blood gas analysis allowed titration of therapy. All patients also received continuous veno-venous haemofiltration.

Results

All four patients recovered to normal or near normal lactate and pH between 10 and 24 hours of therapy. Two patients had significant separation in time between initiation of HID and haemofiltration to suggest an independent effect of HID on improving pH and lactate.All patients had at least one episode of hypoglycaemia below 4.0 mmol/L with the lowest glucose in any patient during therapy being 3.0 mmol/L. All episodes were corrected with a dextrose infusion without sequelae.

Conclusions

Our study demonstrates that HID therapy appears to be safe in patients with suspected metformin poisoning. It also appears to work to drive down lactate, improve pH and patients' clinical condition. Further evidence is required to assess the effectiveness of HID therapy in the context of MALA.

[Acute intoxications: markers for screening, diagnosis and therapy monitoring]

Acute poisonings account for a significant proportion of the patient population presenting to intensive care units, whereby mixed drug overdoses and prescription drug overdoses predominate. The aim of this article was to describe indications for screening, diagnosis and therapy monitoring in acute overdoses in the intensive care unit. To conduct this work, a literature search was carried out and a review was written based on guidelines, case reports, expert opinions and scientific publications. Toxidromes are a useful tool for classification of clinical characteristics when the causative agent is initially unknown. Especially in critical care medicine, identifying and quantifying of the causative toxin by enzyme immunoassays, chromatography and mass spectrometry should be attempted. Intensive care treatment of patients with acute overdoses includes not only monitoring and support of vital functions but also methods for primary and secondary elimination of toxins. The indication for the use of extracorporeal procedures should be carefully evaluated and the method should be chosen based on protein binding and molecular size. Lipid emulsion therapy, high-dose insulin euglycaemia therapy and hyperbaric oxygenation are also increasingly used.