Toxicologic issues during cardiopulmonary resuscitation

PURPOSE OF REVIEW

The following review intends to outline the unique aspects of providing cardiopulmonary resuscitation for the poisoned patient and highlights both current practice and new therapies that apply to toxicologic cases.

RECENT FINDINGS

Although there are few prospective randomized studies to further evidence-based care of the poisoned patient, there have been several reports of novel uses of both established medications and new medications in toxicologic patients. These case reports highlight treatment possibilities and potential avenues for further research.

SUMMARY

It is important for providers to recognize the limitations of standard advanced cardiac life support algorithms when caring for poisoned patients. Toxicologic causes of cardiopulmonary compromise should be considered along with administration of appropriate antidotes and adjunctive therapies.

Pediatric Toxicology

Pediatric patients present unique concerns in the field of medical toxicology. First, there are medicines that are potentially dangerous to small children, even when they are exposed to very small amounts. Clinicians should be wary of these drugs even when young patients present with accidental ingestions of apparently insignificant amounts. Next, over-the-counter laxatives and syrup of ipecac, although not commonly considered abused substances, may be misused in both the setting of Munchausen's syndrome by proxy and in adolescents who have eating disorders. Their use should be considered in any gastrointestinal illness of uncertain origin. Finally, as the use of syrup of ipecac at home now has been discouraged by many, some have explored using activated charcoal at home as a new method of prehospital gastrointestinal decontamination. The literature examining activated charcoal and its use in this capacity is discussed.

Pharmacokinetics of Quetiapine in Overdose and the Effect of Activated Charcoal

The aim of the study was to investigate the pharmacokinetics of quetiapine overdose and the effect of charcoal. The data set included 204 concentration-time points from 54 quetiapine overdose events (median dose 2,700 mg (300-24,000 mg)). Charcoal was administered 0.5-6 h after 19 overdoses. A fully Bayesian methodology for population pharmacokinetic analysis was used and data were modelled using WinBUGS. Uncertainty in the dose history was considered in model building by estimating dose amount and dose time within a possible range. Inclusion of informative priors stabilized the model and population parameter values could be estimated well. A one-compartment model with first-order input and first-order elimination described the data. The final model included uncertainty in dose time. The median and interquartile range of the half-life for individual patients was 6.6 h (4.9-8.4 h). Charcoal was estimated to reduce fraction absorbed by 35%. Co-ingested CYP3A4 inhibitors appeared to decrease clearance and CYP3A4 inducers increase clearance. Charcoal administration may be beneficial after quetiapine overdose.

Activated charcoal for pediatric poisonings: the universal antidote?

PURPOSE OF REVIEW

For decades, activated charcoal has been used as a 'universal antidote' for the majority of poisons because of its ability to prevent the absorption of most toxic agents from the gastrointestinal tract and enhance the elimination of some agents already absorbed. This manuscript will review the history of activated charcoal, its indications, contraindications, and the complications associated with its use as reported in the literature.

RECENT FINDINGS

Recent randomized prospective studies, although with small numbers, have shown no difference in length of hospital stay, morbidity, and mortality between groups who received and did not receive activated charcoal. No study has had sufficient numbers to satisfactorily address clinical outcome in patients who received activated charcoal less than 1 h following ingestion.

SUMMARY

If used appropriately, activated charcoal has relatively low morbidity. Due to the lack of definitive studies showing a benefit in clinical outcome, it should not be used routinely in ingestions. AC could be considered for patients with an intact airway who present soon after ingestion of a toxic or life-threatening dose of an adsorbable toxin. The appropriate use of activated charcoal should be determined by the analysis of the relative risks and benefits of its use in each specific clinical scenario.

Compliance for single and multiple dose regimens of superactivated charcoal: a prospective study of patients in a clinical trial

BACKGROUND

Although activated charcoal is widely used for the treatment of self-poisoning, its effectiveness is unknown. An important consideration is patient compliance since poor compliance will limit effectiveness. We aimed to describe compliance in a randomized controlled trial (RCT) performed in Sri Lanka, presuming that this would set the upper limits for compliance in routine clinical use.

METHOD

1,103 patients randomized to single or multiple (six doses q4h) 50 g doses of superactivated charcoal were prospectively observed. Charcoal was given by study doctors who recorded the amount ingested and the amount of persuasion required for the patients to drink the charcoal.

RESULTS

559 patients were randomized to receive one dose and 544 to receive six doses. Data was available for 1,071 (97%) patients. Eighty-eight were unable to complete their course; 98 required a NG tube, leaving 885 patients that received the first dose by mouth. The mean estimated amount of the prescribed dose of charcoal taken orally as a single or first dose was 83% (95% C.I. 82-84%). For patients receiving multiple doses, this amount fell over the next five doses to 66% (63-69%). While only 3.2% of patients refused the first dose, 12.3% refused the sixth. Relatively less persuasion was required for patients ingesting the first or single dose; 38% of patients required intense persuasion by the sixth dose.

CONCLUSION

Compliance for a single dose of superactivated charcoal among trial patients was good. However, even in the ideal circumstances of a RCT, compliance decreased thereafter for patients taking more than one dose.

Salicylate poisoning: an evidence-based consensus guideline for out-of-hospital management

A review of U.S. poison center data for 2004 showed over 40,000 exposures to salicylate-containing products. A guideline that determines the conditions for emergency department referral and pre-hospital care could potentially optimize patient outcome, avoid unnecessary emergency department visits, reduce health care costs, and reduce life disruption for patients and caregivers. An evidence-based expert consensus process was used to create the guideline. Relevant articles were abstracted by a trained physician researcher. The first draft of the guideline was created by the lead author. The entire panel discussed and refined the guideline before distribution to secondary reviewers for comment. The panel then made changes based on the secondary review comments. The objective of this guideline is to assist poison center personnel in the appropriate out-of-hospital triage and initial out-of-hospital management of patients with a suspected exposure to salicylates by 1) describing the process by which a specialist in poison information should evaluate an exposure to salicylates, 2) identifying the key decision elements in managing cases of salicylate exposure, 3) providing clear and practical recommendations that reflect the current state of knowledge, and 4) identifying needs for research. This guideline is based on an assessment of current scientific and clinical information. The expert consensus panel recognizes that specific patient care decisions may be at variance with this guideline and are the prerogative of the patient and the health professionals providing care, considering all of the circumstances involved. This guideline does not substitute for clinical judgment. Recommendations are in chronological order of likely clinical use. The grade of recommendation is in parentheses: 1) Patients with stated or suspected self-harm or who are the victims of a potentially malicious administration of a salicylate, should be referred to an emergency department immediately. This referral should be guided by local poison center procedures. In general, this should occur regardless of the dose reported (Grade D). 2) The presence of typical symptoms of salicylate toxicity such as hematemesis, tachypnea, hyperpnea, dyspnea, tinnitus, deafness, lethargy, seizures, unexplained lethargy, or confusion warrants referral to an emergency department for evaluation (Grade C). 3) Patients who exhibit typical symptoms of salicylate toxicity or nonspecific symptoms such as unexplained lethargy, confusion, or dyspnea, which could indicate the development of chronic salicylate toxicity, should be referred to an emergency department (Grade C). 4) Patients without evidence of self-harm should have further evaluation, including determination of the dose, time of ingestion, presence of symptoms, history of other medical conditions, and the presence of co-ingestants. The acute ingestion of more than 150 mg/kg or 6.5 g of aspirin equivalent, whichever is less, warrants referral to an emergency department. Ingestion of greater than a lick or taste of oil of wintergreen (98% methyl salicylate) by children under 6 years of age and more than 4 mL of oil of wintergreen by patients 6 years of age and older could cause systemic salicylate toxicity and warrants referral to an emergency department (Grade C). 5) Do not induce emesis for ingestions of salicylates (Grade D). 6) Consider the out-of-hospital administration of activated charcoal for acute ingestions of a toxic dose if it is immediately available, no contraindications are present, the patient is not vomiting, and local guidelines for its out-of-hospital use are observed. However, do not delay transportation in order to administer activated charcoal (Grade D). 7) Women in the last trimester of pregnancy who ingest below the dose for emergency department referral and do not have other referral conditions should be directed to their primary care physician, obstetrician, or a non-emergent health care facility for evaluation of maternal and fetal risk. Routine referral to an emergency department for immediate care is not required (Grade C). 8) For asymptomatic patients with dermal exposures to methyl salicylate or salicylic acid, the skin should be thoroughly washed with soap and water and the patient can be observed at home for development of symptoms (Grade C). 9) For patients with an ocular exposure of methyl salicylate or salicylic acid, the eye(s) should be irrigated with room-temperature tap water for 15 minutes. If after irrigation the patient is having pain, decreased visual acuity, or persistent irritation, referral for an ophthalmological examination is indicated (Grade D). 10) Poison centers should monitor the onset of symptoms whenever possible by conducting follow-up calls at periodic intervals for approximately 12 hours after ingestion of non-enteric-coated salicylate products, and for approximately 24 hours after the ingestion of enteric-coated aspirin (Grade C).

Pharmacokinetics of digoxin cross-reacting substances in patients with acute yellow Oleander (Thevetia peruviana) poisoning, including the effect of activated charcoal

Intentional self-poisonings with seeds from the yellow oleander tree (Thevetia peruviana) are widely reported. Activated charcoal has been suggested to benefit patients with yellow oleander poisoning by reducing absorption and/or facilitating elimination. Two recent randomized controlled trials (RCTs) assessing the efficacy of activated charcoal yielded conflicting outcomes in terms of mortality. The effect of activated charcoal on the pharmacokinetics of Thevetia cardenolides has not been assessed. This information may be useful for determining whether further studies are necessary. Serial blood samples were obtained from patients enrolled in an RCT assessing the relative efficacy of single-dose and multiple-dose activated charcoal (SDAC and MDAC, respectively) compared with no activated charcoal (NoAC). The concentration of Thevetia cardenolides was estimated with a digoxin immunoassay. The effect of activated charcoal on cardenolide pharmacokinetics was compared between treatment groups by determining the area under the curve for each patient in the 24 hours following admission, the 24-hour mean residence time, and regression lines obtained from serial concentration points, adjusted for exposure. Erratic and prolonged absorption patterns were noted in each patient group. The apparent terminal half-life was highly variable, with a median time of 42.9 hours. There was a reduction in 24-hour mean residence time and in the apparent terminal half-life estimated from linear regression in patients administered activated charcoal, versus the control group (NoAC). This effect was approximately equal in patients administered MDAC or SDAC. Activated charcoal appears to favorably influence the pharmacokinetic profile of Thevetia cardenolides in patients with acute self-poisoning and may have clinical benefits. Given the conflicting clinical outcomes noted in previous RCTs, these mechanistic data support the need for further studies to determine whether a particular subgroup of patients (eg, those presenting soon after poisoning) will benefit from activated charcoal.

Management of dofetilide overdose in a patient with known cocaine abuse

Dofetilide, a class III antiarrhythmic agent, is prescribed for conversion to and maintenance of normal sinus rhythm in patients with persistent atrial fibrillation or atrial flutter. Most antiarrhythmics have significant toxicities such as torsade de pointes, and patients should be closely monitored while receiving antiarrhythmic therapy. However, we know of no reports concerning management of intentional overdose of dofetilide that have been published. We report the case of a 33-year-old man who was treated for ingestion of approximately 5 mg of dofetilide as a suicide attempt. In addition, he had a known history of cocaine abuse. He came to the emergency department approximately 45 minutes after the ingestion; examination revealed a QTc interval of approximately 570 msec. He was treated with activated charcoal and sorbitol by nasogastric tube and received aggressive supplementation with potassium and magnesium. The patient was monitored by telemetry for several days and responded well. Cardiac toxicity is the utmost concern when treating dofetilide overdose. The mainstay of treatment focuses on supportive care and prevention of drug absorption. Ventricular dysrhythmias or torsade de pointes should be treated according to advanced cardiac life support guidelines.

Colchicine use in children and adolescents with familial Mediterranean fever: literature review and consensus statement

The daily application of colchicine is the standard therapy for prophylaxis of attacks and amyloid deposition in familial Mediterranean fever. However, because of many issues (eg, dosage, time of introduction, etc), no standardized treatment recommendations have been established. In this work we review the available literature on colchicine use with respect to its indication, efficacy, mode of application, and safety in children and adolescents with familial Mediterranean fever. On the basis of this analysis, a consensus statement on the application of colchicine in children and adolescents with familial Mediterranean fever was developed by caregivers from Germany, Austria, and Turkey.

European first aid guidelines

AIM

Our objectives were to determine the most effective, safe, and feasible first aid (FA) techniques and procedures, and to formulate valid recommendations for training. We focussed on emergencies involving few casualties, where emergency medical services or healthcare professionals are not immediately present at the scene, but are available within a short space of time. Due to time and resource constraints, we limited ourselves to safety, emergency removal, psychosocial FA, traumatology, and poisoning. Cardiopulmonary resuscitation (CPR) was not included because guidelines are already available from the European Resuscitation Council (ERC). The FA guidelines are intended to provide guidance to authors of FA handbooks and those responsible for FA programmes. These guidelines, together with the ERC resuscitation guidelines, will be integrated into a European FA Reference Guide and a European FA Manual.

METHODS

To create these guidelines we used an evidence-based guideline development process, based on the methodology of the Scottish Intercollegiate Guidelines Network (SIGN).

RESULTS

The recommendations cover FA for bleeding, wounds, burns, spinal and head trauma, musculoskeletal trauma, and poisoning, as well as safety and psychosocial FA.

CONCLUSIONS

Where good evidence was available, we were able to turn science into practice. Where evidence was lacking, the recommendations were consensus-based. These guidelines provide systematically developed recommendations and justifications for the procedures and techniques that should be included in FA manuals and training programmes.

Demands on scientific studies in clinical toxicology

Scientific case studies in clinical toxicology on single cases or series of similar cases should document sufficient information on the clinical methodology and observations, the medical laboratory methodology and results, the toxicological analyses methodology and results, the source of used reference values for drug/poison concentrations and kinetics with critical discussion of such values, a description and discussion of the toxicodynamic, the toxicological and the kinetic properties of the detected drugs and/or poisons. The data management, statistical analysis and finally the clinical and/or analytical outcomes must also be described and discussed in correlation to already published data. Statistical methods used for evaluation of clinical as well as for analytical data should be described in detail. When possible, quantitative findings should be presented with appropriate indicators of measurement error or uncertainty. Requirements for such studies are discussed.

The acute treatment of nerve agent exposure

Nerve agents (NA) are simple and cheap to produce but can produce casualties on a massive scale. They have already been employed by terrorist organizations and rogue states on civilians and armed forces alike. By inhibiting the enzyme acetylcholine esterase, NAs prevent the breakdown of the neurotransmitter acetylcholine. This results in over-stimulation of muscarinic and nicotinic receptors in the autonomic and central nervous systems and at the neuromuscular junction. Increased parasympathetic stimulation produces miosis, sialorrhea, bronchospasm and bronchorrhea. Effects at the neuromuscular junction cause weakness, fasciculations, and eventually paralysis. Central effects include altered behavior and mental status, loss of consciousness, seizures, or apnea. Most deaths are due to respiratory failure. Treatment with atropine competitively blocks the parasympathetic effects. Oximes like pralidoxime salvage acetylcholine esterase by "prying off" NA, provided the attachment has not "aged" to an irreversible bond. This reverses weakness. Benzodiazepines like diazepam are effective against NA induced seizures. Mortality has been surprisingly low. If victims can survive the first 15 to 20 min of a vapor attack, they will likely live. The low mortality rate to date underscores that attacks are survivable and research reveals even simple barriers such as clothing offer substantial protection. This article reviews the properties of NAs and how to recognize the clinical features of NA intoxication, employ the needed drugs properly, and screen out anxious patients who mistakenly believe they have been exposed.

Use of single-dose activated charcoal among Canadian pediatric emergency physicians

OBJECTIVE

Gastric decontamination with single-dose activated charcoal (SDAC) is a mainstay in emergency department (ED) treatment of ingestions. Guidelines updated in 2005 encourage practitioners to use SDAC only in toxic ingestions presenting within 1 hour. Despite these guidelines, adult studies demonstrate a significant lack of consensus. This study examined the proposed use of SDAC for gastric decontamination in common pediatric ingestion scenarios by emergency physicians working in Canadian pediatric EDs.

METHODS

A standardized survey consisting of 5 clinical scenarios was mailed to all physicians with a primary clinical appointment to the ED at 9 Canadian children's hospitals.

RESULTS

One hundred thirty-one physicians were surveyed, and 95 (72%) responded. The majority of respondents were pediatricians (68.1%) with a mean of 15.0 years of experience (SD, 6.8 years). Of those surveyed; 91 (97.8%) would use SDAC for a toxic ingestion presenting in less than 1 hour; 35 (36.8%) would use SDAC for a toxic ingestion presenting after 3 hours; 61 (64.9%) would use SDAC for a nontoxic exploratory ingestion presenting in less than 1 hour; and 29 (30.5%) would use SDAC for a mildly symptomatic intentional ingestion presenting at an unknown time. Eleven (11.7%) would use SDAC for an ingestion of a substance that does not adsorb to SDAC.

CONCLUSIONS

There is variation in the use of SDAC among emergency physicians working in Canadian pediatric EDs. This variation suggests that optimal management is not clear and that continued education and research are required.

Salicylate toxicity associated with administration of Percy medicine in an infant

Percy Medicine is a nonprescription gastrointestinal suspension containing bismuth subsalicylate as the active ingredient (1050 mg/10-ml dose). A 3-month-old infant with colic developed salicylate toxicity requiring hospitalization in the pediatric intensive care unit (PICU) as a result of continued administration of this medicine. Bismuth subsalicylate has an aspirin equivalency conversion factor of 0.479 (approximately half the strength of aspirin). For 3.5 weeks the infant's parents administered the medicine, which provided the equivalent of aspirin 57-84 mg/kg/day with no reported problems. However, on the day of admission the baby presented with central nervous system depression and respiratory distress. Assessment at a local emergency facility revealed metabolic acidosis; his serum salicylate concentration was 747 mg/L. After acute management, the patient was transferred to our hospital, where he was treated with whole bowel irrigation and alkalinization therapy. Subsequently, the baby required 4 days of management in the PICU and 2 additional days of observation in a general nursing unit before he was discharged home without incident. The parents had chosen Percy Medicine based on the picture of a baby on the front of the package and because of its placement on the shelf next to a drug their family physician had recommended previously. Salicylate-containing products are not routinely recommended for children aged 1 year or younger. The general public may assume that over-the-counter products are safe because they do not require a prescription. Health care professionals must be responsible for educating the public regarding risks associated with over-the-counter products and the need to read and follow label directions.

The hospital management of fatal self-poisoning in industrialized countries: an opportunity for suicide prevention?

Suicide by self-poisoning is a prevalent cause of death worldwide. A substantial proportion of individuals who poison themselves come into contact with medical services before they die. Our focus in the current study was the medical management of drug self-poisoning in industrialized countries and its possible contribution to suicide prevention. We reviewed the literature to determine the proportion of self-poisoning suicides who reach hospital alive, the sociodemographic and clinical characteristics of in-hospital overdose deaths, the in-hospital management this group of patients receives, and whether there are specific aspects of pre-hospital care and in-hospital management that have the potential to improve survival. Between 11% and 28% of individuals who died following deliberate ingestion of drugs reached hospital alive. The substances which were most frequently implicated in death were paracetamol (acetaminophen) and paracetamol compounds, tricyclic antidepressants, and benzodiazepines. Most patients received fairly intensive treatment, yet death may have been preventable in a small proportion of cases. Only one intervention (the administration of acetylcysteine) was shown to reduce mortality and this was in a highly selected group of patients (those who had ingested paracetamol and developed fulminant hepatic failure). It is possible that other interventions such as better airway management, the prompt administration of activated charcoal, and improved pre-hospital care may improve outcomes but their potential contribution to suicide prevention needs to be investigated in future studies.

Interventions for paracetamol (acetaminophen) overdose

BACKGROUND

Poisoning with paracetamol (acetaminophen) is a common cause of hepatotoxicity in the Western World. Inhibition of absorption, removal from the vascular system, antidotes, and liver transplantation are interventions for paracetamol poisoning.

OBJECTIVES

To assess the benefits and harms of interventions for paracetamol overdose.

SEARCH STRATEGY

We identified trials through electronic databases, manual searches of bibliographies and journals, authors of trials, and pharmaceutical companies until December 2005.

SELECTION CRITERIA

Randomised clinical trials and observational studies were included.

DATA COLLECTION AND ANALYSIS

The primary outcome measure was all-cause mortality plus liver transplantation. Secondary outcome measures were clinical symptoms, (eg, hepatic encephalopathy, fulminant hepatic failure), hepatotoxicity, adverse events, and plasma paracetamol concentration. We used Peto odds ratios and odds ratios with 95% confidence intervals (CI) for analysis of outcomes. Random- and fixed-effects meta-analyses were performed.

MAIN RESULTS

Ten small and low-methodological quality randomised trials, one quasi-randomised study, and 48 observational studies were identified. It was not possible to perform relevant meta-analyses of randomised trials that have addressed our outcome measures. Activated charcoal, gastric lavage, and ipecacuanha are able to reduce the absorption of paracetamol, but the clinical benefit is unclear. Of these, activated charcoal seems to have the best risk-benefit ratio. N-acetylcysteine seems preferable to placebo/supportive treatment, dimercaprol, and cysteamine, but N-acetylcysteine's superiority to methionine is unproven. It is not clear which N-acetylcysteine treatment protocol offers the best efficacy. No strong evidence supports other interventions for paracetamol overdose. N-acetylcysteine may reduce mortality in patients with fulminant hepatic failure (Peto OR 0.26, 95% CI 0.09 to 0.94, one trial). Liver transplantation has the potential to be life saving in fulminant hepatic failure, but refinement of selection criteria for transplantation and long-term outcome reporting are required.

AUTHORS' CONCLUSIONS

Our results highlight a paucity of randomised trials on interventions for paracetamol overdose. Activated charcoal seems the best choice to reduce absorption. N-acetylcysteine should be given to patients with overdose but the selection criteria are not clear. No N-acetylcysteine regime has been shown to be more effective than any other. It is a delicate balance when to proceed to liver transplantation, which may be life-saving for patients with poor prognosis.

Decontamination

Decontamination is the removal or reduction of chemical, biologic, or radiologic agents from the patient's skin, mucosa, lungs, and gastrointestinal tract. Decontamination is an important step in decreasing the clinical effects of the agent on the patient, as well as protecting coworkers from exposure. For most agents and the vast majority of scenarios, the removal of clothing and a simple 5- to 6-minute shower with soap and water is sufficient to eliminate the risks to the patient and hospital staff. In rare circumstances, additional steps in decontamination including gastric lavage, broncho-alveolar lavage, surgical removal of wound foreign bodies, and administration of activated charcoal, polyethylene glycol electrolyte solution, and radioisotope binding agents, may be necessary.