Non-invasive Airway Management of Comatose Poisoned Emergency Patients

A decreased level of consciousness is a common reason for presentation to the emergency department (ED) and is often the result of intoxication (up to 1% of all ED visits and 3% of intensive care unit (ICU) admission). In France, approximately 165 000 poisoned patients are managed each year.1 Originally developed in head injured patients, the Glasgow Coma Scale (GCS) is a validated reproducible score evaluating the level of consciousness - a GCS ≤ 8 is associated with reduced gag reflex and increased incidence of aspiration pneumonia (with an adjusted odds ratio of 2.32, 95%CI =1.60 to 3.33). However, whether this risk of aspiration pneumonia (AP) may be decreased by early intubation is unknown, and no difference in the risk of AP was reported between patients that were intubated early and patients who were not.

Although it is well established that in trauma patients, a GCS ≤ 8 mandates airway management by endotracheal intubation, it remains unknown whether this strategy should be applied to other etiologies of coma, in particular for acute poisoned patients. Tracheal intubation and mechanical ventilation allow to prevent aspiration pneumonia, to optimize oxygenation and gas exchange.

Investigators will include patients with a decreased level of consciousness (defined by a GCS of 8 or less) caused by acute intoxication (alcohol, recreative drugs, or other prescription drugs (with the exception intoxication with cardiotropic drugs, e.g. beta blockers, calcium channel inhibitor, angiotensin conversion enzyme)). These patients will be included at the initial stage of their management: in the ED, or out of hospital with a pre-hospital emergency physician. Patients with clear proven benefit of intubation will be excluded : patients in shock, patients with suspicion of brain lesion, seizure related with poisoning, visualization of regurgitation of gastric content or sign of respiratory distress. Conservative airway management. Patients will be conservatively managed, i.e. close monitoring and no intubation and mechanical ventilation unless the patient presents a clinical event that needs intubation (shock, sign of respiratory distress, visualization of regurgitation or seizure).

Acute poisoning is a common reason for presentation to the ED or MICU intervention (up to 1% of all ED visits and 3% of intensive care unit (ICU) admission). These patients are often intubated (reported rate ranging from 20 to 50% in different cohort studies), when their GCS is below 8, in order to protect their airways. However there is currently no clear demonstration of its efficacy in this specific target population, while it is known that intubation is associated with morbidity and mortality.

Intubated patients need subsequent intensive care unit admission and invasive monitoring, and this can be associated with increased risk of pulmonary complications, length of hospital-stay, nosocomial infections and cost. In a context of expenditures control in health care, appropriate intensive care resource utilization is an important issue. When considering the increasing demand for intensive care among emergency patients, the importance of health care resource allocation and expenditure control, and the possible absence benefit of intubation and intensive care, an endotracheal airway management of poisoned coma patients might be detrimental.

Thus, if our hypothesis is demonstrated, the results of NICO study will change practice and guidelines for management of acute coma poisoned patients, with less exposure to the morbidity of endotracheal intubation and associated with decrease of ICU stay, and reduction of their health costs.

Inclusion criteria

• Age ≥ 18 years
• Clinical suspicion of acute poisoning (either alcohol, drug or medication)
• Decreased level of consciousness with a GCS ≤ 8 assessed by an emergency physician either in the ED or in the out of hospital field with the mobile intensive care unit (MICU).
• Written informed consent signed by the patient / the trustworthy person / family member / close relative or inclusion in case of emergency
• Patients affiliated to French social security ("AME" excepted)

Exclusion criteria

• Respiratory failure (SpO2 < 90% with oxygen provided by nasal cannula (≤ 4 l/min.), clinical signs of respiratory distress)
• Sustained systolic blood pressure < 90 mmHg despite fluid resuscitation of 1 liter of critalloid
• Witnessed seizure
• Acute cerebral aggression (Traumatic brain injury, intracranial hematoma, stroke)
• Suspected Cardiotropic drugs poisoning (beta blockers, calcium channel inhibitor, angiotensin conversion enzyme), QRS or QT enlargement on ECG.
• Suspected sole intoxication with toxic for which there is an antidote
• Patient under legal protection measure (tutorship or curatorship) and patient deprived of freedom
• Known Pregnant women and breast feeding woman
• Participation in another intervention trial