Table of Contents
Kent R. Olson, MD (in part)
The first priority in the poisoned patient is to assure a patent airway and adequate breathing. Respiratory arrest and pulmonary aspiration are two common complications of depressed mental status that can lead to serious morbidity or death.
- The airway may be obstructed by a floppy tongue or by secretions or vomitus. Position the patient to enhance patency by slightly tilting the head backward (extension of the neck) while lifting the head forward relative to the chest (the “sniffing position”). Or, lift the chin forward by placing your fingers behind the angle of the jaw on each side — this lifts the tongue forward, relieving obstruction, and it often provides an uncomfortable stimulus that may awaken the mildly intoxicated patient.
- Airway injury by thermal or chemical burns may result in swelling and laryngeal obstruction. Look for burns in the oropharynx, stridor or brassy cough. Inutubate early if airway injury is supected.
- Since pulmonary aspiration of gastric contents is a serious complication of coma or seizures, it is important to asses the ability of the patient to protect the airway. Normally, the cough reflex is activated when foreign substances enter the upper trachea. However, with CNS depression these protective reflexes are often dulled and pulmonary aspiration may occur. Various methods have been employed to asses the competency of the airway reflexes, such as determining the gag response, but they are only indirect estimates of the actual airway responsiveness. And, making the patient gag might result in vomiting which increases the risk of aspiration. Other indirect methods of assessing the airway reflex include the eyelash (“blink”) response, nasopharyngeal irritant response (e.g., ammonia capsule or stimulating the nasal passage with a q-tip), or the corneal reflex. None is foolproof but they help to determine if the patient is unable to protect their airway.
- In patients with mild airway depression who are not going to be intubated, it is prudent to place them in the left lateral decubitus position to allow the tongue to fall sideways and to make it less likely that the person will aspirate gastric secretions if they vomit. In the patient with deep coma, an artificial airway can be placed in the nasopharynx or oropharynx to make bag-valve mask ventilation easier while preparing for endotracheal intubation.
INTUBATION AND VENTILATION
The decision to intubate should be based primarily on:
- the patient's level of consciousness
- the interventions that are required for gastrointestinal decontamination
- the likelihood of complications developing suddenly
- the degree to which the patient is cooperating with treatment
- the need to prevent mild respiratory acidosis
If it is obvious that the airway reflexes are impaired (deep coma, no gag or cough reflex) then the patient will need to be intubated endotracheally. This is usually performed via the orotracheal route, although if the patient is breathing spontaneously the nasotracheal route can be used. Rapid sequence intubation (RSI) is a standardized procedure that includes pre-oxygenation, administration of sedative-hypnotic drugs (e.g., midazolam, etomidate) and muscle relaxants (e.g., succinylcholine, rocuronium) in conjunction with orotracheal intubation. After intubation, a rapid assessment is needed to assure that the endotracheal tube is in the trachea and not the esophagus. This is done by listening over the lungs and stomach, watching for chest rise with ventilation, and use of a carbon dioxide detector on the end of the ET tube. Looking for condensation in the ET tube is also helpful.