Gastrointestinal decontamination for acute poisoning

Gastroesophageal intussusception secondary to induction of emesis with subsequent development of septic pericardial effusion after corrective surgery

A juvenile boxer dog was diagnosed with gastroesophageal intussusception that occurred after the induction of emesis with apomorphine. A ventral midline coeliotomy and diaphragmotomy were performed and the intussusception was manually reduced. Despite initial satisfactory recovery, the dog was diagnosed with cardiac tamponade 1 week post-operatively. Escherichia coli was cultured from pericardial and pleural effusion samples. During subtotal pericardiectomy surgery the pericardium was found to be markedly thickened with adhesions to the epicardium, thoracic wall and diaphragm. Substantial haemorrhage and refractory hypotension necessitated the administration of a blood transfusion during surgery. The dog entered cardiac arrest in the immediate post-operative period and cardiopulmonary resuscitation was unfortunately unsuccessful. Gastroesophageal intussusception should be considered a possible severe adverse effect of administering apomorhine to induce emesis in dogs. Additionally, septic pericardial and pleural effusions may occur post-reduction of gastroesophageal intussusception.

Gastrointestinal decontamination of the poisoned patient

Gastrointestinal decontamination has been a historically accepted modality in the emergency management of oral intoxicants. Theoretically, gastric and whole-bowel emptying procedures hinder absorption, remove toxic substances, prevent clinical deterioration, and hasten recovery. This article presents a current overview of gastrointestinal decontamination. It challenges the accepted precepts of gut decontamination and assesses the utility of syrup of ipecac-induced emesis, orogastric lavage, single-dose-activated charcoal, cathartics, and whole-bowel irrigation.

Management of toxic exposure in children

Millions of children ingest household products and medications yearly. The continuous proliferation of new products and pharmaceutic agents makes it difficult for physicians to maintain a current command of toxicologic information. Multiple sources, including poison control centers, can provide information; however, EPs must be familiar with several agents that are either significant for their frequency or for their disproportionate potential for morbidity and mortality in pediatric patients. With this select group of intoxicants, physicians must anticipate cardiovascular and pulmonary instability and rapid changes in central nervous system functioning. Appropriate supportive care requires monitoring of the following: vital signs, level of consciousness, airway control, ventilation and circulatory support, body temperature, urine output, and acid base balance. Once these concerns are addressed, prevention of further absorption, enhancing a product's elimination, and treatment with specific antidotes may enhance supportive care. Care is also likely to be enhanced if the EP recognizes the inherent differences (medically and socially) between adults and children of various ages. Definitive emergency care is completed only after the provision of a developmentally oriented preventive strategy.

Unrecognized pregnancy in the overdosed or poisoned patient

A 22-year-old woman was found in bed unresponsive and hypotensive after an apparent overdose. Subsequent workup in the emergency department identified a ruptured ectopic pregnancy and extensive hemoperitoneum. A significant delay occurred when emergency physicians excluded the possibility of pregnancy because of the patient's normal menstrual history. A qualitative serum or urine pregnancy test is recommended in all women of child-bearing age who present with poisoning or drug overdose.

Ondansetron for treating nausea and vomiting in the poisoned patient

OBJECTIVE

To describe the efficacy of ondansetron for the treatment of poisoning-associated vomiting in two patients following drug intoxication.

PATIENTS

Two self-poisoned adolescent patients.

INTERVENTION

Intravenous ondansetron.

RESULTS

Resolution of nausea and vomiting in both patients.

CONCLUSIONS

Ondansetron appears to be a very effective antiemetic drug for use in selected intoxicated patients.

Potential misuse of ipecac

STUDY OBJECTIVE

To evaluate the use of ipecac by health care professionals.

DESIGN

A descriptive case series based on a one-year review of all calls to a poison center.

SETTING

A university hospital-affiliated regional poison center.

INTERVENTIONS

The use of ipecac was judged appropriate or inappropriate based on the consensus of three professionals associated with the poison center using predetermined contraindications.

MEASUREMENTS AND MAIN RESULTS

In 20% of cases in which ipecac was used, its use was inappropriate. The most common inappropriate situation was that too much time had elapsed from the time of ingestion. Among adults the most common contraindication was the ingestion of a substance known to cause altered mental status. Among children, the most common contraindication was the ingestion of a nontoxic substance or amount of substance. The poison center recommended ipecac inappropriately less often than emergency departments and usually in children ingesting a nontoxic substance. EDs recommended ipecac inappropriately with a broader range of contraindications and more often in adults.

CONCLUSION

Ipecac has potentially adverse consequences and should not be used reflexively. Providers of emergency care should be educated about possible contraindications to its use.

Pediatric gastrointestinal decontamination in acute toxin ingestion

The appropriate implementation of the various modalities of gastrointestinal (GI) decontamination is critical in the management of the pediatric patient who is examined in the emergency department or private office after an acute ingestion. Gastrointestinal decontamination includes gastric lavage, syrup of ipecac, activated charcoal, and whole bowel irrigation. Clinical studies have delineated the role and efficacy of these procedures. Trends in GI decontamination place less emphasis on ipecac and gastric lavage and more emphasis on activated charcoal alone in the patient with a mild overdose. Gastric lavage is indicated in serious ingestion and is most effective if done soon after the exposure. Whole bowel irrigation is the newest addition and has important clinical use in the treatment of serious iron ingestions as well as in older adolescent cocaine body suffers and packers. Indications and contraindications of the various forms of GI decontamination are discussed and relevant clinical studies are reviewed.

Selection of activated charcoal products for the treatment of poisonings

OBJECTIVE

To determine if differences exist among currently available activated charcoal products, and if an evaluation of risk versus benefit provides a guide to product selection.

DESIGN

National survey by mail.

PARTICIPANTS

US manufacturers of activated charcoal products.

RESULTS

Six companies market activated charcoal products in ready-to-use containers. The products differ in surface area of charcoal, sorbitol content, and packaging (aqueous or powdered form). No significant differences were noted in the cost of 25- to 30-g units or efficacy based on surface area of activated charcoal. The addition of sorbitol to activated charcoal, particularly at high concentrations, increases the incidence of adverse effects, especially in children.

CONCLUSIONS

Although differences do exist among currently marketed activated charcoal products, the clinical significance of these variations is unknown. Based on an evaluation of risks and benefits, any activated charcoal product that does not contain sorbitol appears to be a suitable choice for treating poisoning victims.

Gastrointestinal tract perforation with charcoal peritoneum complicating orogastric intubation and lavage

A rare complication of gastric decontamination occurred in a young woman undergoing treatment for tricyclic ingestion. After orogastric intubation and lavage, she developed an acute abdomen and underwent laparotomy. Charcoal was discovered throughout the peritoneum, but concurrent and subsequent efforts failed to localize a specific perforation site. Her hospital course was protracted and complicated by tenacious peritoneal charcoal deposition, persistent peritonitis, and adhesion and abscess formation. She underwent both percutaneous and open abscess drainage, oophorectomy, and small-bowel resection. She required total parenteral nutrition in addition to feeding jejunostomy. This present case constitutes the first report of the clinical consequences of charcoal peritoneum. Outright viscus perforation should be considered among potential complications of orogastric intubation and lavage in the poisoned patient. Methods to minimize risks of its occurrence are suggested.

Update in medical toxicology

This article examines some current issues in toxicologic care. First there is a review of the scope of pediatric poisonings and some aspects of initial management. Then there is a discussion of the decision-making process required to properly use gastric decontamination in the management of poisonings. Each of the common methods available--emesis, gastric lavage, activated charcoal, catharsis, and whole bowel irrigation--is discussed. Finally, several new and old antidotes are reviewed, namely naloxone, glucagon, bicarbonate, dimercaptosuccinic acid, digoxin-specific fab fragments, and flumazenil.

Potential pharmacodynamic effect of charcoal on theophylline neurotoxicity in normal rats

Previously, it has been found that repeated oral administration of activated charcoal (AC) to rats with renal failure markedly decreased the sensitivity of the CNS to the neurotoxic-convulsant effect of theophylline. The present study was designed to investigate whether this effect also occurs in normal rats. Normal rats received AC per os in either a single dose or in six doses every 8 h. Control animals received equal volumes of water. Two hours following the last AC dose, animals were infused IV with theophylline until the onset of maximal seizures. Although rats pretreated with repeated administrations of activated charcoal required a larger total theophylline dose to induce convulsions, the theophylline concentrations in the serum and brain at the onset of the neurotoxic episode were not affected by the charcoal pretreatment. It is, therefore, concluded that the gastrointestinal dialysis produced by the activated charcoal had no apparent effect on theophylline-induced neurotoxicity in normal rats.

Malposition of pediatric gastric lavage tubes demonstrated radiographically

Gastric lavage may be indicated in the initial treatment of toxic substance ingestion. We retrospectively surveyed the charts of 36 pediatric patients who underwent gastric lavage to evaluate the clinical and radiographic evidence indicating proper tube placement. Only 14 patients had a radiograph prior to lavage, and 50% of these documented malposition. The most common was excess tube insertion, stretching the stomach inferiorly towards the pelvis. The traditionally acceptable clinical test by auscultation of insufflated air was favorable in 100% of patients, thus failing to detect all of the malpositionings documented radiographically. We suggest that initial insertion of tube length be based on the patient's height or length using an adaptation of Strobel's previously published formula for esophageal pH probe placement: Tube Insertion Depth (TID), orogastric = 9.7 cm + (0.226 x length of patient in cm) and TID, nasogastric = 8 cm + (0.252 x length of patient in cm). These formulae have been displayed in graphic form for easy use. Diagnostic imaging remains the only certain means to document tube placement. Prospective studies to validate the formulae in clinical use are ongoing.

Prevention of chloroquine absorption by activated charcoal

1. The ability of activated charcoal to prevent the absorption of chloroquine was investigated in healthy volunteers, and the effect of the charcoal-chloroquine ratio on the completeness of binding was studied in vitro. 2. After an overnight fast, six subjects ingested 500 mg of chloroquine phosphate with water, and another group of six subjects ingested 25 g of charcoal suspension within 5 min of chloroquine intake. The concentrations of chloroquine in plasma and whole blood were measured by high-performance liquid chromatography for 192 h. 3. Activated charcoal reduced the areas under the plasma and whole blood chloroquine concentration-time curves (AUC) from 0 to 192 h, the total AUCs, and the peak concentrations by 99% (P less than 0.001). 4. Chloroquine was very effectively bound by activated charcoal in vitro, even at low charcoal-chloroquine ratios. For example, at a ratio of 5:1, about 98% of chloroquine was bound. 5. Activated charcoal should be very effective in reducing the absorption of that fraction of chloroquine dose which is in the stomach at the time of charcoal administration. Because the acute toxicity of chloroquine is extremely high and death usually occurs within 1-3 h of overdosage, charcoal should be given as early as possible in suspected chloroquine intoxication.

Drug overdose — reducing the load

OBJECTIVE

To review available information about various methods for reducing gastrointestinal absorption of a poison or drug.

DATA SOURCES

Articles on overdose and accidental poisoning generated by the Australian Medlars Service and concentrating on the period between 1985 and 1990 were surveyed. Earlier studies were included if relevant.

STUDY SELECTION AND DATA EXTRACTION

English language articles with an emphasis on studies using objective methods to measure individual and comparative efficacy of gastrointestinal decontamination techniques were selected. A total of 65 articles were reviewed.

DATA SYNTHESIS

Gastric emptying procedures (gastric lavage or emesis caused by syrup of ipecac) are only effective if performed within one hour of drug ingestion. Gastric lavage is superior to syrup of ipecac. Oral administration of activated charcoal is more effective than either gastric emptying procedure, and is recommended for most cases of poisoning. Cathartics (sorbitol) can be used with activated charcoal. Whole bowel lavage with polyethylene glycol is indicated in selected cases of potentially lethal overdose where the toxic substance cannot be absorbed by charcoal and has passed the pylorus.

CONCLUSIONS

Children--syrup of ipecac can be given at home to children older than 12 months. Most children who reach hospital can be treated by charcoal alone. ADULTS--Most patients are managed with supportive care and, in the absence of contraindications, a single dose of activated charcoal if seen within four hours of ingestion of the poison or drug. Gastric lavage is used if the patient presents within one hour of ingestion and has clinical features of toxicity.

Effect of activated charcoal on the absorption of amiodarone

1 The ability of activated charcoal to prevent the absorption of amiodarone was studied in 18 healthy volunteers, divided into three groups of six subjects. 2 All subjects were administered a single dose of 400 mg amiodarone; one group ingested the drug with water only (control) and the second with 25 g of activated charcoal as a water suspension. The subjects in the third group were given 25 g of charcoal immediately after the 1.5 h blood sample. 3 The extent of amiodarone absorption was reduced by about 98% by simultaneously administered charcoal (P less than 0.001); taking charcoal 1.5 h after amiodarone still resulted in a 50% reduction in amiodarone bioavailability (P less than 0.05). 4 These results indicate that activated charcoal should be effective in preventing amiodarone absorption in acute poisoning.

Peripheral pharmacokinetics of apomorphine in humans

Apomorphine, a potent dopamine agonist, has been used in acute and chronic studies of parkinsonism and other neurological disorders. To define its peripheral pharmacokinetics, we administered apomorphine by subcutaneous injection, by subcutaneous infusion, and by intravenous infusion to 15 patients with parkinsonism and measured plasma apomorphine levels by high-performance liquid chromatography with electrochemical detection. The peak drug levels and area under the curve were closely correlated with the dose administered; time to peak was brief and was independent of dose. The variation in absorption was high between subjects but low within individual subjects. In 11 of 15 subjects, the disappearance of drug could be described by a two-compartment model, with a distribution half-life of 5 minutes and an elimination half-life of 33 minutes. The drug absorption, volume of distribution, plasma clearance, and half-lives were similar for subcutaneous injection, subcutaneous infusion, and intravenous infusion. We conclude that apomorphine is rapidly and completely absorbed from subcutaneous tissue, correlating with the rapid onset of clinical effects, and that the brief duration of clinical action of the drug is explained by its rapid clearance.

Hypermagnesemia associated with catharsis in a salicylate-intoxicated patient with anorexia nervosa

While clinicians have raised concerns about giving multiple doses of a cathartic as a part of therapy for acute poisoning, fears of excessive magnesium absorption or fluid or electrolyte imbalances have been largely unrealized. We present the case of a 19-year-old woman with anorexia nervosa and long-term laxative abuse who, despite a normal baseline serum magnesium concentration, developed hypermagnesemia during treatment with multiple doses of activated charcoal-magnesium citrate for acute salicylate intoxication. The peak serum magnesium concentration, after two doses of magnesium citrate, reached 9.8 mg/dL (4.0 mmol/L). It fell to normal levels when sorbitol was substituted as a cathartic and after the patient had been hemodialyzed for symptoms of salicylate toxicity that continued despite conventional therapy. While disordered magnesium metabolism in one patient with a severe underlying medical condition should not interdict the use of repetitive doses of magnesium citrate as a cathartic, patients requiring such therapy should have serum magnesium concentrations measured serially to monitor for signs of magnesium loading.

Sorbitol catharsis does not enhance efficacy of charcoal in a simulated acetaminophen overdose

The use of a 70% sorbitol solution has recently been advocated as an adjunct to activated charcoal. This results in rapid and profuse catharsis that could possibly cause fluid and electrolyte imbalance. An investigation was undertaken to determine if sorbitol catharsis enhanced the antidotal efficacy of activated charcoal. Eight healthy volunteers participated in a randomized, crossover trial. Subjects ingested 3 g of acetaminophen followed by either no intervention, 50 g of plain activated charcoal at one hour, or 50 g activated charcoal-sorbitol solution at one hour. Serial acetaminophen levels were determined at intervals over eight hours and side effects noted. Both interventions significantly reduced the area under the curve versus control (P less than .05). The addition of sorbitol did not enhance the efficacy of activated charcoal but did increase the side effects noted. Sorbitol has not been proven effective in enhancing drug removal and has side effects that can be significant in a poisoned patient. Current data do not warrant its use, and further investigations should be carried out with other ingested drugs.

Quinine poisoning in children

The accidental ingestion of quinine by children causes significant morbidity and mortality. We have reviewed quinine poisoning as presented in the medical literature and our experience of paediatric quinine poisoning during the period from January 1975 to September 1986. The clinical features that were seen in our patients were similar to those that are described in larger series. In our series, 13 children were identified, of whom 11 children were aged one to two years. Ten children either remained asymptomatic or made a complete recovery. Two children had a persisting major deficit and one died. Once ingestion of quinine has occurred, absorption should be prevented by the emptying of the stomach with ipecacuanha or gastric lavage promptly and then by the administration of activated charcoal. Once toxicity develops, supportive therapy should be given, but there is no specific therapy to reduce toxicity or to enhance elimination. Physicians who prescribe quinine should be aware of the potential dangers to small children.