A retrospective review of the prehospital use of activated charcoal

Abstract

Objective

We studied the complications and timing implications of prehospital activated charcoal (PAC). Appropriateness of PAC administration was also evaluated.

Methods

We retrospectively reviewed prehospital records over 32 months for overdose cases, where PAC was administered. Cases were assessed for amount and type of ingestant, clinical findings, timing of PAC, timing of transport and arrival into the emergency department (ED), and complications. Encounter duration in cases of PAC was compared with that, for all cases during the study period, where an overdose patient who did not receive activated charcoal was transported.

Results

Two thousand eight hundred forty-five total cases were identified. In 441 cases, PAC was given; and complications could be assessed. Two hundred eighty-one of these had complete information regarding timing of ingestion, activated charcoal administration, and transport. The average time between overdose and PAC was 49.8 minutes (range, 7-199 minutes; median, 41.0 minutes; SD, 30.4 minutes). Complications included emesis (7%), declining mental status (4%), declining blood pressure (0.4%), and declining oxygen saturation (0.4%). Four hundred seventeen cases of PAC had documentation of timing of emergency medical service (EMS) arrival on scene and arrival at the ED. Average EMS encounter time was 29 minutes (range, 10-53 minutes; median, 27.9 minutes). Two thousand forty-four poisoning patients were transported who did not receive PAC. The average EMS encounter time for this group was 28.1 minutes (range, 4-82 minutes; median, 27.3 minutes), not significantly different (P = .114).

Conclusions

Prehospital activated charcoal did not appear to markedly delay transport or arrival of overdose patients into the ED and was generally safe.

Introduction

Activated charcoal (AC) is the preferred method of decontamination when indicated for a variety of intoxicants. Activated charcoal contains a complex pore structure and a large surface area allowing it to bind intoxicants in the gastrointestinal tract, thereby preventing systemic absorption. It is generally well tolerated and has few side effects [1]. Activated charcoal can be given for a wide variety of toxic ingestions but is not generally recommended for poisonings with alcohol, hydrocarbons, corrosives, or heavy metals [1], [2]. Timing of charcoal administration is crucial to its efficacy in oral overdose, as several volunteer studies have shown that AC can significantly reduce drug absorption when given within 1 hour of drug ingestion, but becomes much less effective if given more than 1 hour after ingestion [3], [4], [5].

For the period examined in this study, our city's protocol for the administration of AC included ingestion of a substance potentially bound by AC with a cooperative patient whose gag reflex is intact. Paramedics in our prehospital system in many cases contact our local poison control center for assistance in management of overdose patients before arrival in an emergency department (ED). In some cases, this prevents transport, when a nontoxic exposure has occurred. City prehospital protocol allows administration of up to 50 g of AC by standing order or in consultation with our poison control center or a base hospital. Consultation with poison control or a base hospital is not mandatory for AC to be administered. The protocol in use during the study period specifically did not distinguish between substances ingested when recommending AC but does exclude its use in cases of isolated alcohol, heavy metals (including iron), caustic agents, and hydrocarbons.

Although the relative safety of AC in the hospital setting has been established, few studies have examined the safety of AC in the prehospital setting [6], [7]. In addition, there may be concern that the administration of AC in the field may delay transport of patients and ultimately delay their arrival into the ED. We attempted to examine ambulance transport times, appropriateness of administration, and complications in prehospital AC administration.