Indications for Intubation (Emergency AirWay Management (EAM) part 1)

Airway skills are perhaps the most important skills that an emergency physician possesses. If the airway is lost in a critically ill patient for any reason, any of the other interventions you might make, or any great diagnoses are superfluous. It is good to remember that in the ABC’s of resuscitation, airway is first and foremost. With the exception of defibrillation in a cardiac arrest situation and possibly a needle decompression in the patient with a tension pneumothorax, airway control always assumes first priority. Since the need to protect the airway most often occurs in a crisis situation in the ED, the emergency physician can not rely on others, like anesthesia, to assist. Even moments of delay can spell disaster for the patient. Since every airway emergency presents in a different fashion, the emergency physician must be proficient in multiple techniques to protect and intubate the airway, and must be prepared with all the necessary equipment to perform these alternative procedures should the initial plan fail.

Indications for Intubation
There are several indications for intubation. The first occurs when the patient is unable to protect or maintain his/her airway. An example of this might be someone deeply comatose from a head injury or drug overdose who can not protect his airway from aspiration if vomiting should occur. It has been taught that the absence of the gag reflex is a reliable method of assessing whether or not the airway is protected. In fact this might not be the case. Up to 20% of the normal population may not have a gag reflex. A better assessment of airway protection is evaluation of the ability to swallow spontaneously and handle secretions. Even if the patient is “breathing on his own” and ventilation is adequate, this does not assure us that the patient will be protect his airway if vomiting were to occur, and the morbidity and mortality from aspiration is quite high. The second indication is failure of oxygenation or ventilation as might occur in someone with asthma, COPD or pulmonary edema. If the PaO2 can not be maintained with supplemental oxygen or such techniques as BiPAP, the patient will ultimately need ventilation through endotracheal intubation. The third is an anticipated clinical course that makes airway management imperative. This might include such patients as those with oropharyngeal burns from a house fire, facial trauma or facial abscesses. Airway compromise in these conditions is a real possibility and airway management often becomes increasingly difficult as time passes. If there is an anatomical distortion that will make intubation more difficult as time goes on, it is the wise physician who will recognize the problem and provide simple protection before the process progresses.
Once it has been established that airway intervention will be necessary, there are several questions the emergency physician must ask: How much time do I have? Is this a critical airway and a crash situation? Do I need to intubate now or do I have a few minutes to prepare? If you are in a crash situation like a full cardiopulmonary arrest, orotracheal intubation must proceed without further delay. If there is time to prepare, then the physician must predict which airway intervention is best and most likely to succeed. He must evaluate whether this will be a difficult airway to intubate and if it is a difficult airway and the first attempt at intubation fails, can the patient be ventilated with a bag-valve-mask. [If I am unable to intubate and I can not ventilate with a bag-valve-mask, am I prepared to manage the situation?]

Rapid Sequence Intubation
In most cases, airway management will be amenable to standard practices. “Rapid sequence intubation is the cornerstone of modern emergency airway management.
Although other techniques, such as blind nasotracheal intubation and intubation using sedation along with neuromuscular blockade, have been used widely in the past, the superiority of rapid sequence intubation in terms of success rates, complication rates and control of adverse effects, renders it clearly the procedure of choice for the majority of emergency department intubations.” (ACEP-Advanced Airway Management) “Rapid sequence intubation is the virtually simultaneous administration of a potent sedative (induction) agent and a rapidly acting neuromuscular blocking agent to induce unconsciousness and motor paralysis for tracheal intubation.” (ACEP- Advanced Airway Management) Although there are no absolute contraindications for rapid sequence intubation, the presence of a potentially difficult airway requires a careful assessment and a plan with alternatives should the intubation attempt fail.
Rapid sequence intubation (RSI) consists of a series of discrete steps that are best followed to insure the greatest success. The patient should first be evaluated for the presence of a difficult airway and the ability to ventilate with a bag-valve-mask should intubation not be successful. It is obvious that the intubation should take place in a room that is prepared in advance with all equipment needed for resuscitation should that be necessary. It is the physician’s responsibility to make sure that all equipment is present and in working order before proceeding! Although nurses may assure you that everything is in working order, the physician is ultimately responsible and will be the one to have to handle the problem if some critical equipment is not functioning or a critical drug is not available.

Reference
Advanced Emergency Airway Management Walls RM, Luten RC, Murphy ME, Schneider RE.
1997