Lipid emulsion therapy in cardiodepressive syndrome after diltiazem overdose—case report

Electrocardiogram Features in Non-Cardiac Diseases: From Mechanisms to Practical Aspects

Despite the noteworthy advancements and the introduction of new technologies in diagnostic tools for cardiovascular disorders, the electrocardiogram (ECG) remains a reliable, easily accessible, and affordable tool to use. In addition to its crucial role in cardiac emergencies, ECG can be considered a very useful ancillary tool for the diagnosis of many non-cardiac diseases as well. In this narrative review, we aimed to explore the potential contributions of ECG for the diagnosis of non-cardiac diseases such as stroke, migraine, pancreatitis, Kounis syndrome, hypothermia, esophageal disorders, pulmonary embolism, pulmonary diseases, electrolyte disturbances, anemia, coronavirus disease 2019, different intoxications and pregnancy.

A case of local anesthetic toxicity that wasn't: lipid rescue from self-administered benzodiazepine overdose in labor

A 32-year-old G2P1 woman presented for induction of labor at term. Her past medical history included polysubstance use disorder and methadone maintenance, scant prenatal care, morbid obesity, and intimate partner violence. Her induction was progressing smoothly until the acute onset of altered mental status near to the time of delivery, several minutes after a clinician-administered epidural local anesthetic bolus for significant pain. Given concern about local anesthetic systemic toxicity, lipid emulsion was administered and resulted in an immediate and drastic clinical response. The epidural infusion bag and pump system were evaluated and found to be correct and there was no clinical suspicion of an intravascular epidural catheter. The woman remained stable and was transferred to the postpartum unit, where she experienced a similar episode of altered mental status approximately 12 h postpartum. This episode self-resolved and she was managed conservatively. Shortly after this event, it was discovered that the patient had been self-administering benzodiazepines throughout the course of her labor, in addition to her hospital staff-administered medications. Presumably, her intrapartum altered mental status was a result of self-administered benzodiazepine that was then "rescued" with lipid emulsion. This case illustrates the potential for lipid emulsion as a reversal agent for medications other than local anesthetics.

Literature review of the evidence regarding intravenous lipid administration in drug-induced cardiotoxicity

Introduction: Intravenous lipid emulsion (ILE) administration is capable of reversing the acute cardiac and neurological toxicity caused by local anesthetic agents. In recent years, ILE has also been explored as a potential antidote for cardiotoxicity caused by non-anesthetic agents too. Areas covered: The potential mechanisms, safety, and efficacy of this approach are considered. Data were sought from published reports listed in PubMed and EMBASE, and abstracts of meetings of the North American Congress of Clinical Toxicology and European Association of Poisons Centres and Clinical Toxicologists. There were reports involving 298 patients where ILE has been administered for severe drug toxicity. Clinical improvement was observed in 57 of 59 patients with local anesthetic toxicity (96.6%); there were 239 patients where toxicity was due to non-anesthetic agents, and ILE apparently improved clinical outcome in 215 (72.1%). Expert opinion: Response rates were similar between ILE treated toxicity caused by lipid soluble and non-lipid soluble drugs. Potential adverse effects of ILE include interference with laboratory assays, acute pancreatitis, and adult respiratory distress syndrome, although the rate of occurrence is difficult to ascertain.

Bilateral blindness secondary to optic nerve ischemia from severe amlodipine overdose: a case report

Background

Calcium channel blockers are commonly prescribed medications; calcium channel blocker overdose is becoming increasingly prevalent. The typical presentation of a calcium channel blocker overdose is hypotension and decreased level of consciousness. We describe a case of a calcium channel blocker overdose that led to bilateral cortical blindness, a presentation that has not previously been reported.

Case presentation

A 49-year-old white woman with known bilateral early optic atrophy presented to our hospital with hypotension and obtundation following a known ingestion of 150 mg of amlodipine. She was transferred to our intensive care unit where she was intubated, mechanically ventilated, and required maximal vasopressor support (norepinephrine 40 mcg/minute, epinephrine 40 mcg/minute, and vasopressin 2.4 units/hour) along with intravenously administered crystalloid boluses. Despite these measures, she continued to deteriorate with persistent hypotension and tachycardia, as well as anuria.

Intralipid emulsion therapy was subsequently administered to which no initial response was observed. A chest X-ray revealed diffuse pulmonary edema; intravenous diuresis as well as continuous renal replacement therapy was initiated.

Following the initiation of continuous renal replacement therapy, her oxygen requirements as well as urine output began to improve, and 3 days later she was liberated from mechanical ventilation. Following extubation, she complained of new onset visual impairment, specifically seeing only red-green colors, but no objects. An ophthalmologic examination revealed that this was due to bilateral optic atrophy from prolonged hypotension during the first 24 hours after the overdose.

Conclusion

Persistent hypotension in the setting of a calcium channel blocker overdose can lead to worsening optic atrophy resulting in bilateral cortical blindness.

Intravenous Lipid Emulsion for Management of Systemic Toxic Effects of Drugs

The incidence of toxic effects of drugs leading to emergency department visits has increased in the United States in the past several years. Most of these patients can be adequately managed by supportive care alone. However, pharmacological antidotes may be necessary, particularly in patients with hemodynamic instability. In severe cases refractory to conventional antidote therapy, rescue therapy with intravenous lipid emulsion (ILE) may be necessary. Traditionally, ILE has been used as an antidote of choice in treating toxic effects of local anesthetics. But data continue to emerge on the successful use of ILE to treat overdoses of drugs other than local anesthetics, particularly lipophilic medications. The recommended ILE dose is a 1.5 mL/kg bolus followed by infusion of 15 mL/kg per hour, with repeat dosing permissible for continued hemodynamic instability. Use of ILE should be considered early as a rescue therapy in the settings of lipophilic medication overdoses when cardiovascular compromise or cardiac arrest is present.

Pilot Trial of Intravenous Lipid Emulsion Treatment for Severe Nifedipine-Induced Shock

Animal studies and human case reports show promise in using lipid rescue to treat refractory calcium channel antagonist toxicity. However, the majority of research and clinical experience has focused on non-dihydropyridine agents. Thus, we sought to investigate the value of lipid emulsion (ILE) therapy for dihydropyridine-induced shock. This IACUC-approved study utilized seven swine that were sedated with alpha-chloralose, mechanically ventilated, and instrumented for drug delivery and hemodynamic measures. After stabilization and basal measures, nifedipine (0.01875 mg/kg/min) was infused until imminent cardiac arrest (seizure, end tidal CO2 < 10 mmHg, bradydysrhythmia, or pulseless electrical activity). Animals then received a 7 mL/kg bolus of 20% lipid emulsion via central catheter. Lipid circulation was visually confirmed by the presence of fat in peripheral arterial blood. Hemodynamics were continuously monitored until 10 min after lipid bolus. Surviving animals were euthanized. Pre- and post-lipid treatment parameters were analyzed using the Wilxocon signed rank test (p <0.05 significant). Nifedipine toxicity was characterized by vasodilatory hypotension, impaired vascular contractility, and tachycardia with terminal bradycardia. The median time to imminent cardiac arrest from start of nifedipine infusion was 218 min. Lipid treatment did not improve hemodynamics or restore circulation in any animal. There was no benefit from lipid rescue in this model of nifedipine toxicity. Further study of ILE for dihydropyridine toxicity is warranted but initial animal model results are not promising.

Asystole immediately following intravenous fat emulsion for overdose

Use of intravenous fat emulsion (IFE) for the treatment of poisoned patients in extremis is increasing. Little literature exists describing failures and complications of IFE. We describe two cardiac arrests temporally associated with IFE. A 50-year-old woman presented after ingesting 80 total tablets of metoprolol 25 mg and bupropion 150 mg. Bradycardia and hypotension were refractory to calcium salts, catecholamines, and high dose insulin (HDI). With a pulse of 40/min and mean arterial pressure (MAP) of 30 mmHg, 100 mL of 20 % IFE was given; within 30 s, brady-asystolic arrest occurred. Pulses returned after 3 min of CPR. The patient died on hospital day 4 of multisystem organ failure (MSOF). A 53-year-old man presented after ingesting of 3,600 mg of diltiazem and 1,200 mg of propranolol. Bradycardia and hypotension were refractory to calcium salts, catecholamines, HDI, bicarbonate, and atropine. With a pulse of 30/min and a MAP of 40 mmHg, 150 mL of 20 % IFE was given; within 1 min, a brady-asystolic arrest occurred. Pulses returned after 6 min of CPR. The patient died on hospital day 7 of MSOF. Reported cases of IFE failures or potential complications are sparse. This report adds only case experience, not clarity. We report two cardiac arrests that were temporally associated with IFE.

The effects of intravenous lipid emulsion on prolongation of survival in a rat model of calcium channel blocker toxicity

CONTEXT

Intravenous lipid emulsion (ILE) has been shown to ameliorate the toxicity of lipid-soluble agents in animal studies and clinical cases.

OBJECTIVES

To investigate the therapeutic effects of ILE in a rat model of toxicity from calcium channel blockers (CCBs), including diltiazem and nicardipine.

METHODS

Two sets of experiments of CCB poisoning were conducted. In the first set, 14 male Sprague-Dawley rats were sedated and treated with ILE or normal saline (NS), followed by continuous intravenous infusion of diltiazem (20 mg/kg/h). In the second experiment, the study protocol was the same except the infusion of nicardipine (20 mg/kg/h). The total dose of infused drug and the duration of survival were measured. In addition, mean arterial pressure and heart rate were monitored.

RESULTS

Survival was prolonged in the ILE group (48.4 ± 11.3 vs. 25.0 ± 3.7 min; p = 0.002). Furthermore, the cumulative mean lethal dose of diltiazem was higher in the ILE group (16.1 ± 3.8 mg/kg) than in the NS group (8.3 ± 1.1 mg/kg) (p = 0.002). With nicardipine poisoning, survival was also prolonged in the ILE group (71.0 ± 8.3 min vs. 30.6 ± 6.1 min; p = 0.002). The cumulative mean lethal dose was higher in the ILE group than in the NS group (23.7 ± 2.8 mg/kg vs. 10.2 ± 2.0 mg/kg; p = 0.002).

CONCLUSIONS

ILE pretreatment prolonged survival and increased the lethal dose in a rat model of CCB poisoning using diltiazem and nicardipine.

Treatment for calcium channel blocker poisoning: a systematic review

CONTEXT

Calcium channel blocker poisoning is a common and sometimes life-threatening ingestion.

OBJECTIVE

To evaluate the reported effects of treatments for calcium channel blocker poisoning. The primary outcomes of interest were mortality and hemodynamic parameters. The secondary outcomes included length of stay in hospital, length of stay in intensive care unit, duration of vasopressor use, functional outcomes, and serum calcium channel blocker concentrations.

METHODS

Medline/Ovid, PubMed, EMBASE, Cochrane Library, TOXLINE, International pharmaceutical abstracts, Google Scholar, and the gray literature up to December 31, 2013 were searched without time restriction to identify all types of studies that examined effects of various treatments for calcium channel blocker poisoning for the outcomes of interest. The search strategy included the following Keywords: [calcium channel blockers OR calcium channel antagonist OR calcium channel blocking agent OR (amlodipine or bencyclane or bepridil or cinnarizine or felodipine or fendiline or flunarizine or gallopamil or isradipine or lidoflazine or mibefradil or nicardipine or nifedipine or nimodipine or nisoldipine or nitrendipine or prenylamine or verapamil or diltiazem)] AND [overdose OR medication errors OR poisoning OR intoxication OR toxicity OR adverse effect]. Two reviewers independently selected studies and a group of reviewers abstracted all relevant data using a pilot-tested form. A second group analyzed the risk of bias and overall quality using the STROBE (STrengthening the Reporting of OBservational studies in Epidemiology) checklist and the Thomas tool for observational studies, the Institute of Health Economics tool for Quality of Case Series, the ARRIVE (Animal Research: Reporting In Vivo Experiments) guidelines, and the modified NRCNA (National Research Council for the National Academies) list for animal studies. Qualitative synthesis was used to summarize the evidence. Of 15,577 citations identified in the initial search, 216 were selected for analysis, including 117 case reports. The kappa on the quality analysis tools was greater than 0.80 for all study types.

RESULTS

The only observational study in humans examined high-dose insulin and extracorporeal life support. The risk of bias across studies was high for all interventions and moderate to high for extracorporeal life support. High-dose insulin. High-dose insulin (bolus of 1 unit/kg followed by an infusion of 0.5-2.0 units/kg/h) was associated with improved hemodynamic parameters and lower mortality, at the risks of hypoglycemia and hypokalemia (low quality of evidence). Extracorporeal life support. Extracorporeal life support was associated with improved survival in patients with severe shock or cardiac arrest at the cost of limb ischemia, thrombosis, and bleeding (low quality of evidence). Calcium, dopamine, and norepinephrine. These agents improved hemodynamic parameters and survival without documented severe side effects (very low quality of evidence). 4-Aminopyridine. Use of 4-aminopyridine was associated with improved hemodynamic parameters and survival in animal studies, at the risk of seizures. Lipid emulsion therapy. Lipid emulsion was associated with improved hemodynamic parameters and survival in animal models of intravenous verapamil poisoning, but not in models of oral verapamil poisoning. Other studies. Studies on decontamination, atropine, glucagon, pacemakers, levosimendan, and plasma exchange reported variable results, and the methodologies used limit their interpretation. No trial was documented in humans poisoned with calcium channel blockers for Bay K8644, CGP 28932, digoxin, cyclodextrin, liposomes, bicarbonate, carnitine, fructose 1,6-diphosphate, PK 11195, or triiodothyronine. Case reports were only found for charcoal hemoperfusion, dialysis, intra-aortic balloon pump, Impella device and methylene blue.

CONCLUSIONS

The treatment for calcium channel blocker poisoning is supported by low-quality evidence drawn from a heterogeneous and heavily biased literature. High-dose insulin and extracorporeal life support were the interventions supported by the strongest evidence, although the evidence is of low quality.

Nutrition as medical therapy

Recent data support the use of nutritional agents for use as targeted medical therapy. This article reviews some of the pharmacologic roles that parenteral nutritional ingredients (selenium, lipid emulsion, insulin, and levocarnitine) can play in the setting of critical illness.