The association of cardiovascular toxins and electrocardiographic abnormality in poisoned patients

The limited utility of screening laboratory tests and electrocardiograms in the management of unintentional asymptomatic pediatric ingestions

BACKGROUND

Suspected ingestions are a common chief complaint to the emergency department although the majority of ingestions by children are insignificant.

OBJECTIVE

Assess the utility of screening laboratory tests and Electrocardiograms (ECGs) in unintentional asymptomatic pediatric poisonings.

METHODS

Retrospective chart review at a tertiary care children's hospital and a regional poison center of patients less than 12 years of age using ICD-9 codes from January 2005 through December 2008. Laboratory or ECG results requiring intervention and/or direct treatment, a non-RPC subspecialty consultation, and/or prolonged Emergency Department stay was considered changed management.

RESULTS

Five hundred ninety five suspected ingestions met our criteria. The median age was 2.6 years (IQR 1.6, 3.0 years) and 56% were male. One laboratory test or ECG was obtained in 233 patients (39%). Of 24 screening ECGs, 32 complete blood counts and 34 blood gases, none were clinically significant. Fifty-two patients received screening metabolic panels, 3 were abnormal and 2 changed management (anion gap metabolic acidosis with unsuspected salicylate ingestions). None of the 127 (21%) screening acetaminophen levels changed management. Two of sixty-five (13%) screening salicylate levels changed management. Three screening urine toxicology tests on patients with altered mental status were positive without ingestion history. No patient under the age of 12 years with normal vital signs and normal mental status had positive screening tests.

CONCLUSIONS

Screening laboratory tests and ECGs were of limited utility and rarely changed management despite being ordered in a significant number of patients. Screening tests are rarely indicated in unintentional overdoses in children who are asymptomatic.

Toxidromes

The critical care physician is often called to care for poisoned patients. This article reviews the general approach to the poisoned patient, specifically focusing on the utility of the toxidrome. A toxidrome is a constellation of findings, either from the physical examination or from ancillary testing, which may result from any poison. There are numerous toxidromes defined in the medical literature. This article focuses on the more common toxidromes described in clinical toxicology. Although these toxidromes can aid the clinician in narrowing the differential diagnosis, care must be exercised to realize the exceptions and limitations associated with each.

Management of the critically poisoned patient

BACKGROUND

Clinicians are often challenged to manage critically ill poison patients. The clinical effects encountered in poisoned patients are dependent on numerous variables, such as the dose, the length of exposure time, and the pre-existing health of the patient. The goal of this article is to introduce the basic concepts for evaluation of poisoned patients and review the appropriate management of such patients based on the currently available literature.

METHODS

An unsystematic review of the medical literature was performed and articles pertaining to human poisoning were obtained. The literature selected was based on the preference and clinical expertise of authors.

DISCUSSION

If a poisoning is recognized early and appropriate testing and supportive care is initiated rapidly, the majority of patient outcomes will be good. Judicious use of antidotes should be practiced and clinicians should clearly understand the indications and contraindications of antidotes prior to administration.