Comparative evaluation of Glasgow Coma Score and gag reflex in predicting aspiration pneumonitis in acute poisoning☆
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.
References (26)
- et al.
Relation between Glasgow Coma Scale and aspiration pneumonia
Lancet
(1996) - et al.
Inadequate assessment of the airway and ventilation in acute poisoning. A need for improved education?
Resuscitation
(1999) - et al.
Aspiration pneumonia following severe self-poisoning
Resuscitation
(2003) - et al.
The use of receiver operating characteristic curves in biomedical informatics
J Biomed Inform
(2005) - et al.
The role of anaerobes in patients with ventilator-associated pneumonia and aspiration pneumonia: a prospective study
Chest
(1999) - et al.
Interrater reliability of Glasgow Coma Scale scores in the emergency department
Ann Emerg Med
(2004) - et al.
Interobserver variability in the use of APACHE II scores
Lancet
(1999) - et al.
Position paper: gastric lavage
J Toxicol Clin Toxicol
(2004) - et al.
Aspiration pneumonitis in an overdose population: frequency, predictors, and outcomes
Crit Care Med
(2004) - et al.
Incidence, risk factors, and outcome of aspiration pneumonitis in ICU overdose patients
Intensive Care Med
(2006)
Toxicology handbook
Evaluation of the Glasgow Coma Scale score in critically ill infectious disease patients
Infection
Relation of body position at the time of discovery with suspected aspiration pneumonia in poisoned comatose patients
Crit Care Med
Cited by (22)
Airway Management of Respiratory Failure
2016, Emergency Medicine Clinics of North AmericaCitation Excerpt :In the setting of trauma, a GCS of 8 or lower signifies coma. Eizadi-Mood et al10 demonstrated aspiration pneumonitis was more likely in patients with low GCS (<6) in a population of poisoned patients undergoing gastric lavage. It is widely accepted that comatose patients are unable to maintain their airway and need definitive airway management.
Aspiration pneumonia: A review of modern trends
2015, Journal of Critical CareCitation Excerpt :Adnet and Baud [60] demonstrated an association between the degree of AMS (as measured by Glasgow Coma Scale) and aspiration, supporting the pathophysiologic link between the entities. Most available case series focus on the association of acute AMS with chemical pneumonitis in the setting of sedation, poisoning, and trauma [15,61–63]. In these populations, vomiting and large-volume reflux of gastric contents may also increase the risk of aspiration pneumonia.
Basic Airway Management
2012, Emergency Medicine: Clinical Essentials, SECOND EDITIONWhat is the relationship between the Glasgow coma scale and airway protective reflexes in the Chinese population?
2012, ResuscitationCitation Excerpt :These studies add to the weight of evidence that the current common practise of using GCS ≤ 8 as a marker of a patient's ability to protect their own airway may be inappropriate and detrimental to some patients. Most of the research into the relationship of airway reflexes with GCS has concentrated on patients with alcohol intoxication, poisoning and head injury.4,5,10 In addition, most previous studies have been in predominantly young, Caucasian populations.
Tu-Be or Not Tu-Be…That is the Question: Commentary on “Prehospital Intubation of Patients with Severe Traumatic Brain Injury”
2023, Prehospital Emergency Care
- ☆
The manuscript or parts of it have not been and will not be submitted elsewhere for publication.