Elsevier

Journal of Critical Care

Volume 24, Issue 3, September 2009, Pages 470.e9-470.e15
Journal of Critical Care

Comparative evaluation of Glasgow Coma Score and gag reflex in predicting aspiration pneumonitis in acute poisoning

https://doi.org/10.1016/j.jcrc.2008.08.008Get rights and content

Abstract

Purpose

The purpose of the study was to assess the incidence of aspiration pneumonitis (AP) and its association with gag reflex and Glasgow Coma Score (GCS).

Materials and Methods

In a retrospective analysis study after prospective data collection, 155 poisoned patients with GCS less than or equal to 12 were evaluated. An assessment of GCS and the quality of gag reflex was made on arrival and recorded. Intubation status before gastrointestinal decontamination was noted. All patients were subsequently followed for developing of AP.

Results

The incidence of AP was 15.5%, with significant variance among patients with respect to the gag reflex, GCS, and the performance of intubation. A logistic regression model for predicting AP contained the following predictors: GCS (odds ratio [OR], 0.43; 95% confidence interval [CI], 0.30-0.62), intubation (OR, 0.07; 95% CI, 0.01-0.49), organophosphate ingestion (OR, 1.39; 95% CI, 0.96-2.01), and gastric evacuation (OR, 4.29; 95% CI, 0.94-9.51). In patients with reduced gag reflex, variations in GCS were associated with AP (OR, 0.43; 95% CI, 0.20-0.90), whereas in patients with absent gag reflex, age was the most important predictor of AP (OR, 2.67; 95% CI, 0.99-7.22).

Conclusions

A reduced GCS and a nonintubated trachea are associated with an increased incidence of AP.

Introduction

There has been a considerable shift among the toxicology community of the Western world away from the routine use of gastrointestinal decontamination procedures in the setting of acute poisonings [1]. This may relate in part to a risk-benefit assessment grounded in the reality that most Western poisonings follow the ingestion of pharmaceuticals, with associated case mortality rates that are low by virtue of legislative restrictions on drug availability, the ready availability of good quality supportive care, and adequate antidote supplies.

Our experience in our Poisoning Emergency Department (PED) is somewhat different from that common to Western toxicology as a consequence of the frequent ingestion of high-lethality chemical compounds (insecticides, pesticides, etc) and a less regulated approach to pharmaceutical distribution. The combined effect is large numbers of poisoning presentations and a preponderance of high-grade clinical toxicity. As a consequence of this experience, there has been reluctance among local practitioners to move away from historically used decontamination techniques that are considerably more interventional than existing international guidelines.

It is standard practice in our institution for most patients to receive gastric evacuation followed by activated charcoal. Gastric evacuation is performed by inserting a small-bore nasogastric tube (NGT), suctioning gastric contents, and then repeated irrigation and reaspiration of 50- to 150-mL boluses of water until aspirates are clear (thus departing from traditional gastric lavage techniques).

This practice falls outside existing guidelines for the practice of gastrointestinal decontamination [1] and has not previously been formally evaluated. Our institutional approach to airway protection during these decontamination procedures centers on an assessment of the gag reflex, with intubation before decontamination routine for patients with absent gag reflexes, left to individual practitioner discretion for those with reduced (but present) gag, and not performed for patients with normal gag. Quantitative assessments of the level of obtundation (such as the Glasgow Coma Score [GCS]) are not routinely used.

Few studies have directly addressed the problem of aspiration pneumonitis (AP) in the poisoned patient. A number of authors have attempted to identify risk factors associated with the development of AP [2], [3], [4], [5], [6]. The use of formal gastric lavage and activated charcoal increases the risk of AP in the patient with a reduced level of consciousness and an unprotected airway [5]. The GCS, age, sex, and time from ingestion to presentation, emesis, seizure, and tricyclic antidepressant ingestion have been shown to be associated with aspiration in poisoned patients [3]. These statistical associations, however, offer little clinical guidance given that the time between ingestion and presentation, and the occurrence of seizures or vomiting before arrival in hospital are often unknown. Laryngeal reflexes, gag reflex, and level of consciousness are the only available clinical parameters available to emergency physicians as aids in the decisions regarding airway intervention before gastrointestinal decontamination.

This study was designed to evaluate the following:

  • 1- The incidence of AP in poisoned patients within our institution and the variance of that incidence within subgroups determined by the quality of gag reflex and GCS on arrival (GCS <8 and GCS ≥8), and the election to intubate or not before gastrointestinal decontamination.

  • 2- The predictive value of GCS and gag reflex on arrival for the subsequent development of AP.

  • 3- The discriminatory power of admission GCS in predicting AP and, by inference, the need for intubation before gastrointestinal decontamination.

Section snippets

Materials and methods

The PED of Noor University Hospital is a main referral center of Isfahan Province, Iran, and is specifically staffed and designed exclusively for the management of poisoned patients. Approximately 400 patients are admitted monthly; and their initial care is managed under the supervision of a clinical toxicologist with the input and involvement of anesthesiology, intensive care, and forensic medicine. This study involved prospective data collection followed by retrospective analysis and was

Results

During the study, 155 eligible poisoned patients were evaluated. The patients were divided into 3 groups: normal (58.1%), reduced (23.8%), and absent (18.1%) gag reflexes. The proportion of AP with respect to age, sex, toxic agents, the time from ingestion to presentation, gag reflex, GCS, gastric evacuation, activated charcoal administration, and outcome is shown in Table 1. The median (25th-75th percentiles) GCS score was 10 (9-11) for patients with normal gag reflex, 7 (6-8) for patients

Discussion

The incidence of AP in our study was 15.5%. Drug overdose is a common cause of aspiration, with historical estimates of its incidence ranging from 29% to 50% [12], [13], [14]. These previous studies have only included patients admitted to an intensive care unit. In contrast, our study includes all poisoned patients presenting to a PED, which makes the results more generalizable.

Aspiration pneumonitis was seen in patients with an absent gag reflex who were intubated on arrival to the PED,

Conclusions

It is concluded that impairments in GCS and gag reflex are related to the subsequent development of AP in the setting of our clinical practice. Intubation before decontamination was observed to be protective. The combination of an impaired gag and reduced GCS would appear to confer additional risk of AP; therefore, early tracheal intubation in the poisoned patients with a reduced gag reflex and impaired GCS may be suggested to prevent AP, particularly where gastrointestinal decontamination is

Acknowledgment

The authors would like to thanks the members of the Anaesthesiology and Intensive Care Department, Isfahan University of Medical Sciences; the staff of the PED; and Dr H Shariatmadari for their valuable support.

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