Venoarterial extracorporeal membrane oxygenation for the management of massive amlodipine overdose

Diagnosis and Management of Vasoplegia in Temporary Mechanical Circulatory Support: A Narrative Review

Refractory vasodilatory shock, or vasoplegia, is a pathophysiologic state observed in the intensive care unit and operating room in patients with a variety of primary diagnoses. Definitions of vasoplegia vary by source but are qualitatively defined clinically as a normal or high cardiac index and low systemic vascular resistance causing hypotension despite high-dose vasopressors in the setting of euvolemia. This definition can be difficult to apply to patients undergoing mechanical circulatory support (MCS). A large body of mostly retrospective literature exists on vasoplegia in the non-MCS population, but the increased use of temporary MCS justifies an examination of vasoplegia in this population. MCS, particularly extracorporeal membrane oxygenation, adds complexity to the diagnosis and management of vasoplegia due to challenges in determining cardiac output (or total blood flow), lack of clarity on appropriate dosing of noncatecholamine interventions, increased thrombosis risk, the difficulty in determining the endpoints of adequate volume resuscitation, and the unclear effects of rescue agents (methylene blue, hydroxocobalamin, and angiotensin II) on MCS device monitoring and function. Care teams must combine data from invasive and noninvasive sources to diagnose vasoplegia in this population. In this narrative review, the available literature is surveyed to provide guidance on the diagnosis and management of vasoplegia in the temporary MCS population, with a focus on noncatecholamine treatments and special considerations for patients supported by extracorporeal membrane oxygenation, transvalvular heart pumps, and other ventricular assist devices.

Treatment Modalities in Calcium Channel Blocker Overdose: A Systematic Review

Calcium channel blocker poisoning is one of the most common poisonings encountered which presents with life-threatening complications. However, there is no unified approach for treating these patients in the existing literature. This study aimed to assess the effects of different treatment modalities used in calcium channel blocker poisoning, as reported by previous studies. The primary outcomes studied were mortality and hemodynamic parameters after treatment. The secondary outcomes were the length of hospital stay, length of intensive care unit stay, duration of vasopressor use, functional outcomes, and serum calcium channel blocker concentrations. A thorough literature search was performed through Ovid, PubMed, Cochrane Library, and Google Scholar from January 2014 to December 31, 2022, to identify all studies analyzing the effects of the treatment of calcium channel blocker poisoning on the desired outcomes. Two reviewers reviewed 607 published articles from January 2014 to December 2022 to identify studies analyzing the effects of the treatment of calcium channel blocker poisoning on desired outcomes. In this review, 18 case reports, one case series, and one cohort study were included. Most patients were treated with an injection of calcium gluconate or calcium chloride. The use of calcium along with dopamine and norepinephrine was found to have lower mortality rates. A few patients were also treated with injection atropine for bradycardia. High-dose insulin therapy was used in 14 patients, of whom two did not survive. In the cohort study, 66 calcium channel blocker toxicity patients were included. These patients were treated with high-dose insulin therapy. A total of 11 patients with calcium channel blocker toxicity succumbed. Although it was found to be associated with improved hemodynamic parameters and lower mortality, side effects such as hypokalemia and hypoglycemia were noted. Intravenous lipid emulsion therapy (administered to eight patients), extracorporeal life support (used in three patients with refractory shock or cardiac arrest), injection glucagon, methylene blue, albumin infusion, and terlipressin were associated with a lower mortality rate as well as improvement in hemodynamic parameters. None of the case reports provided any information on end-organ damage on long-term follow-up.

Angiotensin axis antagonists increase the incidence of haemodynamic instability in dihydropyridine calcium channel blocker poisoning

CONTEXT

Amlodipine, a dihydropyridine calcium channel blocker (CCB), is the leading cause of cardiovascular drug-related overdose deaths in the USA. In contrast, angiotensin-II receptor blockers (ARBs) and angiotensin converting enzyme inhibitors (ACEIs) cause minimal toxicity in overdose. ACEIs/ARBs are often combined with dihydropyridines in hypertension treatment. Co-ingested ARBs/ACEIs may significantly contribute to the toxicity of dihydropyridine, but this has not been investigated.

OBJECTIVE

To investigate the clinical outcomes from dihydropyridine overdoses with ARBs/ACEIs versus dihydropyridine overdoses alone.

METHODS

This was a retrospective study of patients reported to the New South Wales Poisons Information Centre (NSW PIC) and 3 toxicology units (Jan 2016 to Jun 2019) in Australia. Patients >14 years who took an overdose of dihydropyridines (amlodipine, felodipine, lercanidipine, nifedipine) were included. Concurrent overdoses with non-dihydropyridine CCBs, alpha-blockers and beta-blockers were excluded. Patient demographics, drugs exposure details, serial vital signs, treatments and outcome were collected.

RESULTS

There were 100 patients. 68 took mixed overdoses of dihydropyridines with ARBs/ACEIs and 32 took single overdoses of dihydropyridines without ARBs/ACEIs. The mixed group had lower median nadir mean arterial pressures (62 vs 75 mmHg, p < 0.001), more frequently had hypotension (OR 4.5, 95%CI: 1.7-11.9) or bradycardia (OR 8.8, 95%CI: 1.1-70). Multivariable analysis indicated the mixed overdoses had an 11.5 mmHg (95%CI: 4.9-18.1) lower minimum systolic blood pressure (SBP) compared with the single group; other factors associated with a lower minimum SBP were higher doses [2.3 mmHg (95%CI: 1.1-3.5) lower per 10 defined daily doses] and younger age [2.2 mmHg (95%CI: 0.3-4.2) higher per decade]. A larger proportion of the mixed ingestion group received intravenous fluids (OR 5.7, 95%CI: 1.8-18.6) and antidotes and/or vasopressors (OR 2.9, 95%CI: 1.004-8.6).

CONCLUSION

Combined overdoses of dihydropyridines with ARBs/ACEIs caused more significant hypotension and required more haemodynamic support than overdoses of dihydropyridines alone.

Clinical utility of midodrine and methylene blue as catecholamine-sparing agents in intensive care unit patients with shock

Shock is common in the intensive care unit, affecting up to one third of patients. Treatment of shock is centered upon managing hypotension and ensuring adequate perfusion via administration of fluids and catecholamine vasopressors. Due to the risks associated with catecholamine vasopressors, interest has grown in using catecholamine-sparing agents such as midodrine and methylene blue. Midodrine is an orally administered alpha-1 adrenergic agonist while methylene blue is an intravenously administered blue dye used to restore vascular tone and increase blood pressure. Separate MEDLINE, Scopus, and Embase database searches were conducted to assess literature revolving around these agents. Examples of search terms included "midodrine", "methylene blue", "critically ill", "shock", and "catecholamine-sparing." Several studies have evaluated their use in patients with shock and found potential benefits in terms of causing significant elevations in blood pressure and hastening catecholamine vasopressor discontinuation with few adverse effects; however, robust evidence is lacking for these off-label indications. Because of the variety of dosing strategies used and the incongruences between patient populations, it is also challenging to define finite recommendations. This review aims to summarize current evidence for the use of midodrine and methylene blue as catecholamine-sparing agents in critically ill patients with resolving or refractory shock.

Severe Amlodipine Toxicity: A Case Rescued with Extracorporeal Membrane Oxygenation

Amlodipine is a widely prescribed drugs for the management of hypertension. Its toxicity is associated with severe myocardial depression and refractory hypotension. We present a case of a 28-year-old female known case of seizure disorder and depression who got admitted to our hospital with a history of consumption of 80 tablets of 5 mg amlodipine (total 400 mg). Patient presented to our hospital after 23 hours following consumption of the drug. Patient was managed in the intensive care unit (ICU) with mechanical ventilation support and intravenous infusion of noradrenalin, adrenalin, insulin-dextrose, and calcium gluconate. Due to refractory hypotension, venoarterial extracorporeal membrane oxygenation (VA-ECMO) was initiated on the same day. Patient was successfully managed and discharged home on the 8th day. This report highlights a rare case of a massive amlodipine overdose (400 mg) and ECMO as a rescue therapy.

How to cite this article

Sutar A, Venkategowda PM, Murthy A, Chikkaswamy SB. Severe Amlodipine Toxicity: A Case Rescued with Extracorporeal Membrane Oxygenation. Indian J Crit Care Med 2020;24(5):365-366.

Development and Feasibility of a Porcine Model of Amlodipine Toxicity

INTRODUCTION

Toxicity related to calcium-channel blockers remains a significant cause of morbidity and mortality. Amlodipine-induced shock is unique in that its mechanism of action is thought to occur in part via the release of nitric oxide (NO) in the peripheral vasculature. Specific therapeutic interventions, including methylene blue (an NO scavenger), have been suggested, but efficacy studies are severely limited. To facilitate a larger porcine study into the effect of various interventions on amlodipine toxicity, we undertook this model development and feasibility study.

METHODS

Intravenous amlodipine was prepared by dissolving commercially obtained amlodipine tablets in dimethylsulfoxide. The concentration of the drug was verified using ultraviolet spectroscopy. We administered this solution to three animals in order to determine a toxic dose, capable of facilitating a two-arm study of amlodipine toxicity.

RESULTS

The first pig died rapidly after the bolus infusion. The second pig developed mild toxicity, but the dissolution of the plastic tubing by the solvent and subsequent leakage limited the interpretability of the result. The third animal developed expected toxicity with an infusion rate between 2.0  and 5.5 mg/kg/h.

CONCLUSION

This study demonstrates a potentially repeatable model of amlodipine-induced toxic shock using intravenous administration of amlodipine and several methodological considerations for researchers undertaking similar work.

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.

A Case of Severe, Refractory Hypotension After Amlodipine Overdose

Calcium channel blockers (CCBs) are responsible for a substantial portion of the mortality associated with cardiovascular medication overdose cases. Amlodipine, a dihydropyridine CCB, can cause prolonged hypotension in overdose. This report describes a severe amlodipine overdose case that was refractory to multiple therapeutic approaches. A 53-year-old male presented after ingesting eighty 10 mg amlodipine tablets in a suicide attempt. The patient was initially managed with calcium boluses, glucagon, multiple vasoactive agents, lipid emulsion infusions and hyperinsulinemic euglycemic therapy. Methylene blue boluses were initiated when hypotension persisted despite conventional treatments. Refractory hypotension prompted the use of plasmapheresis in an attempt to lower serum amlodipine levels. Finally, the patient was placed on extracorporeal membrane oxygenation (ECMO) to maintain perfusion while the effects of the amlodipine ingestion dissipated. Following an episode of asystole and pulseless electrical activity prior to the start of ECMO, the patient suffered an anoxic brain injury and suspected herniation prompting the family to withdraw medical care. There is limited evidence in the literature describing the refractory treatment modalities utilized in this patient. This report is unique as it describes the clinical course of a patient when a multitude of unique treatments were combined.

Use of veno-venous extracorporeal membrane oxygenation to treat severe combined calcium channel blocker and angiotensin converting enzyme inhibitor overdose

INTRODUCTION

Calcium channel blockers (CCBs) are a commonly prescribed medication that, at toxic levels, are capable of causing severe refractory hypotension, hypoxic respiratory failure and cardiotoxicity. There is little evidence currently guiding the approach to managing CCB overdose, particularly when combined with other antihypertensive agents.

CASE REPORT

We describe the use of veno-venous extracorporeal membrane oxygenation (VV ECMO) in a previously healthy man following combined overdose with amlodipine and lisinopril in a suicide attempt. ECMO was used to provide oxygenation support, allowing for the amlodipine and lisinopril to be metabolized and cleared while also reducing ventilator-induced lung injury (VILI) and avoiding the complications associated with venous-arterial (VA) ECMO, such as differential hypoxemia.

CONCLUSION

Limited case reports suggesting the use of ECMO in CCB overdose have employed VA ECMO due to CCB-induced cardiotoxicity. We believe that, if cardiac function has been preserved, VV ECMO should be considered a viable treatment strategy for CCB and ACE-I overdose resulting in refractory hypoxemic respiratory failure.

Pharmacological and mechanical management of calcium channel blocker toxicity

Cardiovascular instability associated with calcium channel blocker toxicity comprises a small percentage of overdose presentations, yet they are associated with a high mortality rate. We detail the management of a 64-year-old man who took an intentional overdose of 840 mg nimodipine. We include the treatment he received and highlight the scarcity of evidence behind the use of gastric decontamination, calcium, glucagon, intravenous lipid emulsion, high-dose insulin therapy, sodium bicarbonate, vasopressors and methylene blue in calcium channel blocker toxicity. Additionally, the article explores the use of electrical pacing and venoarterial extracorporeal membrane oxygenation (VA-ECMO). Following successful weaning of VA-ECMO, the patient was successfully extubated but remained neurologically impaired due to hypoxic-ischaemic brain injury, critical care polyneuropathy and renal failure requiring dialysis. He has cerebral performance category 3; he has mild cognitive impairment but able to perform some activities of daily living independently and communicate his thoughts and needs. He requires no respiratory or cardiovascular support.

Extracorporeal Membrane Oxygenation in Drug Overdose: A Clinical Case Series

Overdose of cardiovascular medications such as beta blockers and calcium channel blockers cause impaired cardiac contractility, vasoplegia, and/or rhythm disturbances. In addition to conventional management of limiting absorption, increasing elimination and hemodynamic support intravenous (IV) calcium infusion, hyperinsulinemia-euglycemia therapy, glucagon infusion, and IV lipid emulsion have been tried. Extracorporeal circulatory assist device support has been reported as a rescue therapy in overdose refractory to maximal medical therapy. We report three patients with cardiovascular medication overdose presenting with profound cardiovascular instability refractory to medical therapy. Venoarterial extracorporeal membrane oxygenation support (VA ECMO) was initiated to provide hemodynamic support. Despite the occurrence of device-associated complications, the outcome was good and all patients survived. VA ECMO may be considered in patients with severe refractory shock due to cardiotoxic medication overdose.

Examining the role of extracorporeal membrane oxygenation in patients following suspected or confirmed suicide attempts: A case series

The decision to offer extracorporeal membrane oxygenation (ECMO) is based on a risk/benefit assessment and the likelihood of a treatable underlying condition or the feasibility of destination therapy (durable mechanical support or thoracic organ transplantation) should heart-lung function fail to improve. Patients who present following suspected suicide attempts who fail medical therapy may pose a dilemma for clinicians. An assessment to determine if a patient has a high likelihood of psychiatric recovery such that bridging with ECMO or ultimately destination therapy could or should be offered is not always feasible in the setting of critical illness. This case series reviews our institution's experience with ECMO in the management of five patients who presented following suspected or confirmed suicide attempts. All five patients survived to hospital discharge. Two had subsequent psychiatric admissions, one following a repeat suicide attempt. A discussion of these cases demonstrates the effectiveness of ECMO in supporting this group of patients in the short-term. The self-limited natural history of many psychiatric episodes, poisonings and traumatic injuries makes the use of ECMO a potentially reasonable support strategy. However, careful consideration must be given to psychiatric history and follow-up given the substantial commitment of resources, potential for complications and for stranding patients on extracorporeal therapy without definitive destination therapy.

Experts Consensus Recommendations for the Management of Calcium Channel Blocker Poisoning in Adults

OBJECTIVE

To provide a management approach for adults with calcium channel blocker poisoning.

DATA SOURCES, STUDY SELECTION, AND DATA EXTRACTION

Following the Appraisal of Guidelines for Research & Evaluation II instrument, initial voting statements were constructed based on summaries outlining the evidence, risks, and benefits.

DATA SYNTHESIS

We recommend 1) for asymptomatic patients, observation and consideration of decontamination following a potentially toxic calcium channel blocker ingestion (1D); 2) as first-line therapies (prioritized based on desired effect), IV calcium (1D), high-dose insulin therapy (1D-2D), and norepinephrine and/or epinephrine (1D). We also suggest dobutamine or epinephrine in the presence of cardiogenic shock (2D) and atropine in the presence of symptomatic bradycardia or conduction disturbance (2D); 3) in patients refractory to the first-line treatments, we suggest incremental doses of high-dose insulin therapy if myocardial dysfunction is present (2D), IV lipid-emulsion therapy (2D), and using a pacemaker in the presence of unstable bradycardia or high-grade arteriovenous block without significant alteration in cardiac inotropism (2D); 4) in patients with refractory shock or who are periarrest, we recommend incremental doses of high-dose insulin (1D) and IV lipid-emulsion therapy (1D) if not already tried. We suggest venoarterial extracorporeal membrane oxygenation, if available, when refractory shock has a significant cardiogenic component (2D), and using pacemaker in the presence of unstable bradycardia or high-grade arteriovenous block in the absence of myocardial dysfunction (2D) if not already tried; 5) in patients with cardiac arrest, we recommend IV calcium in addition to the standard advanced cardiac life-support (1D), lipid-emulsion therapy (1D), and we suggest venoarterial extracorporeal membrane oxygenation if available (2D).

CONCLUSION

We offer recommendations for the stepwise management of calcium channel blocker toxicity. For all interventions, the level of evidence was very low.

Are vasopressors useful in toxin-induced cardiogenic shock?

OBJECTIVE

Overdoses with cardio-depressive medications can result in toxin-induced cardiogenic shock (TICS), a life-threatening condition characterized by severe hypotension and ineffective tissue perfusion. Vasopressors are often employed in the treatment of shock to increase heart rate and blood pressure. We sought to conduct a systematic review of the literature to evaluate the effectiveness of vasopressors in improving hemodynamic function and survival in the treatment of TICS.

DATA SOURCES

We searched PubMed, EMBASE, TOXLINE, and International Pharmaceutical Abstracts.

STUDY SELECTION

We included studies evaluating the use of vasopressors in humans or animals with TICS. We limited human study types to randomized controlled trials, clinical trials, observational studies, and case reports.

DATA EXTRACTION

Our search yielded 913 citations and 144 of these met our inclusion criteria. 130 were human case reports and 14 were animal studies.

DATA SYNTHESIS

Human case report data showed vasopressors were ineffective more often than they were partially or fully effective. In the majority of animal studies, vasopressor treatment failed to improve hemodynamic parameters and resulted in decreased survival.

CONCLUSIONS

Human case reports and controlled animal experiments lead to different conclusions about vasopressors in TICS. Most animal studies indicate that vasopressors impair hemodynamic function and increase mortality. In contrast, human case reports suggest that vasopressors are often ineffective but not necessarily harmful.

Extracorporeal Membrane Oxygenation Support in Trauma Versus Nontrauma Patients with Noninfectious Acute Respiratory Failure

The utility of extracorporeal membrane oxygenation (ECMO) in patients with acute respiratory distress syndrome (ARDS) of noninfectious origin remains unclear. Data on patients with ARDS of noninfectious origin who underwent ECMO were reviewed retrospectively. We compared the pre-ECMO characteristics and hospital outcomes of patients with traumatic and nontraumatic ARDS. In total, 23 patients (trauma, n = 9; nontrauma, n = 14) were included in the study. The mean patient age was 42 years, there were three females, and the mean pre-ECMO Simplified Acute Physiologic Score (SAPS) II was 60.0 (49.0-71.0). The hemoglobin level was lower and the prothrombin time (PT) more prolonged, prior to initiation of ECMO, in traumatic compared with nontraumatic ARDS patients. During the first 48 h of ECMO support, the coagulation parameters did not differ between the two groups, but the platelet counts, PT, and activated partial thromboplastin time indicated that coagulopathy was developing in all patients. The hospital and 28-day mortality rates were 21.7 and 13.0%, respectively, and serious neurological outcomes (cerebral performance category [CPC] of three points or more) developed in 26.1% of all patients; however, the extent of such outcomes did not differ between traumatic and nontraumatic ARDS patients. Upon multivariate analysis, the pre-ECMO SAPS II tended to be associated with composite events (i.e., hospital death and/or a CPC of three points or more) (P = 0.051). Additionally, a history of hypertension and an elevated pre-ECMO SAPS II were significant risk factors for serious neurological outcomes among hospital survivors (n = 18). In conclusion, ECMO support can be associated with favorable outcomes in patients with ARDS of noninfectious origin, irrespective of whether the ARDS is associated with trauma. The pre-ECMO SAPS II and a history of hypertension may be independent risk factors for poor outcomes.

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.

Extracorporeal membrane oxygenation (ECMO) for critically ill adults in the emergency department: history, current applications, and future directions

Extracorporeal membrane oxygenation (ECMO) is a mode of extracorporeal life support that augments oxygenation, ventilation and/or cardiac output via cannulae connected to a circuit that pumps blood through an oxygenator and back into the patient. ECMO has been used for decades to support cardiopulmonary disease refractory to conventional therapy. While not robust, there are promising data for the use of ECMO in acute hypoxemic respiratory failure, cardiac arrest, and cardiogenic shock and the potential indications for ECMO continue to increase. This review discusses the existing literature on the potential use of ECMO in critically ill patients within the emergency department.

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.

Extracorporeal life support in critically ill adults

Extracorporeal life support (ECLS) has become increasingly popular as a salvage strategy for critically ill adults. Major advances in technology and the severe acute respiratory distress syndrome that characterized the 2009 influenza A(H1N1) pandemic have stimulated renewed interest in the use of venovenous extracorporeal membrane oxygenation (ECMO) and extracorporeal carbon dioxide removal to support the respiratory system. Theoretical advantages of ECLS for respiratory failure include the ability to rest the lungs by avoiding injurious mechanical ventilator settings and the potential to facilitate early mobilization, which may be advantageous for bridging to recovery or to lung transplantation. The use of venoarterial ECMO has been expanded and applied to critically ill adults with hemodynamic compromise from a variety of etiologies, beyond postcardiotomy failure. Although technology and general care of the ECLS patient have evolved, ECLS is not without potentially serious complications and remains unproven as a treatment modality. The therapy is now being tested in clinical trials, although numerous questions remain about the application of ECLS and its impact on outcomes in critically ill adults.