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What every Emergency Physician needs to know

Catherine Williams

Emergency Medicine Consultant, Royal Bolton Hospital, Bolton, UK

Health Education North West, Manchester, UK

People from many different backgrounds, of all ages and with an enormous variety of problems, present to an emergency department (ED) both by day and by night. The definition of 'what constitutes an emergency' is highly variable, and the ED often acts as a medical and societal safety net.

EMERGENCY ASSESSMENT OF THE UNDIFFERENTIATED PATIENT

All emergency physicians must be able to respond to, and manage an undifferentiated patient, presenting with a sudden emergency. A structured initial approach, following the ABCDE format discussed below, will ensure that immediately life-threatening problems are addressed in order or priority. In many cases, where multiple clinicians are involved, these elements may be undertaken in parallel, but it remains important for a team leader to maintain a structured overview.

Cardiac arrest Chapter 11, p. 157.

Children p. 342.

The ABCDE assessment

A rapid initial ABCDE assessment should be possible in about 30?seconds. Immediate threats should be addressed at each stage before moving on.

Special considerations of the ABCDE assessment in trauma Chapter 2, p 22.

A - Airway

The airway may be:

• patent, partially obstructed or completely obstructed (from physical obstruction or loss of muscle tone)
• adequately protected or at risk (this depends on the protective reflexes of the airway).

Check for responsiveness

Is the patient alert and responsive to questions? A verbal reply confirms that there is:

• a maintained and protected airway
• temporarily adequate breathing and circulation
• cerebral functioning.

If responsive, then the patient will usually be able to elaborate on the cause of the sudden deterioration that has brought him or her to an ED.

Failure to respond indicates a significantly lowered level of consciousness and therefore an airway that may be obstructed and is definitely at risk. There may be a need for airway-opening manoeuvres and action to protect the airway.

Foreign body obstruction may initially present as a distressed, very agitated, cyanosed patient - 'choking'.

Cardiorespiratory arrest p. 157.

Choking p. 205.

Respiratory arrest p. 209.

Look for signs of partial upper airway obstruction

Complete upper airway obstruction will be silent.

• Snoring: the familiar sound of obstruction caused by the soft tissues of the mouth and pharynx. Often it accompanies the reduced muscle tone of a lowered level of consciousness.
• Rattling or gurgling: the sound of fluids in the upper airway.
• Stridor: a harsh, 'crowing' inspiratory (or occasionally biphasic) noise. Stridor suggests obstruction at the level of the larynx and upper trachea, which may be caused by foreign body or local infection. In cases of suspected supraglottic swelling, instrumentation of the throat (including the use of tongue depressor) should not be carried out, and examination should be undertaken very carefully as there is a risk of precipitating complete obstruction.
• Drooling:??suggests obstruction at the posterior pharynx.
• Hoarseness: gross voice change suggests obstruction at the level of the larynx.
• 'See-saw' respiration (abdominal expansion with thoracic wall indrawing): is indicative of airway obstruction with ongoing respiratory effort.

Cyanosis and reduced saturation readings on a pulse oximeter are very late signs of airway obstruction.

Allergic reactions p. 306.

Laryngotracheal obstruction p. 205.

Surgical airways p. 23.

Assess the need for cervical spine protection before any airway intervention.

Clearance and maintenance of the airway

There are two main ways in which the airway becomes blocked.

• Depressed level of consciousness: the most common cause. When muscle tone is lost, the relaxation of soft tissues around the airway, in particular the tongue, may precipitate airway obstruction.
• Physical obstruction: from a variety of causes such as direct trauma, external or intramural mass or foreign body.

Airway obstruction may be immediately relieved by:

• removing the cause of the obstruction (suction, manual removal or choking manoeuvre)
• chin lift/head tilt manoeuvre
• jaw thrust - pushing the jaw and the hyoid bone and their attached soft tissues forward
• use of an oro-pharyngeal/nasopharyngeal airway, supraglottic airway (i-gel or laryngeal mask) or endotracheal intubation
• reducing the swelling with vasoconstrictor drugs (adrenaline)
• tracheal intubation
• bypassing the cause of obstruction with a surgical airway.

Protection of the airway

Airway reflexes may be compromised by specific nerve palsies (e.g. stroke), the effect of drugs (including alcohol) and decreased conscious level. They may also be impaired at the extremes of age and in states of general debilitation. Vigilance is required in all such situations as there is a risk of aspiration of vomitus.

• The recovery position should be used whenever possible if consciousness is decreased. This allows fluid and vomitus to drain from the airway under gravity, and the airway should be positioned to ensure patency. A high-flow suction catheter must always be near the patient's head.
• The patient trolley must be capable of tilting 'head down' to drain vomitus out of the airway.

Obtunded patients require consideration of endotracheal intubation for airway protection.

Over 10% of normal individuals have no gag reflex, and thus presence or absence of a gag reflex is not a good predictor of need for intubation.

In a patient with a reduced level of consciousness, the airway must be assumed to be at risk until proved otherwise.

Protection of the cervical spine

If the patient has an injury to the cervical spine, there is a risk of damage to the spinal cord during the procedures needed to maintain the airway. Because of the potentially devastating outcomes of cervical cord injury, care must be taken to protect the cervical spine in patients who are:

• unresponsive with a history of trauma or no clear history
• suffering from multiple trauma
• difficult to assess
• showing any symptoms or signs that might be attributable to the cervical spine.

Adequate protection of the potentially unstable cervical spine conventionally consists of a rigid collar and blocks secured with tape. Cervical immobilisation makes airway management more challenging and can be distressing for the patient and so in these circumstances, manual inline stabilisation may be preferable.

Exclusion of cervical spine injury p. 54.

B - Breathing

Look for

• Difficulty in talking
• Abnormal respiratory rate: usually fast, laboured breathing. Very slow respiratory rates may occur just before respiratory arrest or due to poisoning with respiratory depressant drugs (e.g. opiates)
• Nasal flaring and use of shoulder and neck muscles
• Paradoxical respiration: a see-sawing movement of the chest and abdomen, which indicates airway obstruction, fatigue of the diaphragm or occasionally cervical cord injury
• Unequal, diminished or abnormal breath sounds
• Hyperresonance or dullness to percussion
• Displacement of the trachea or apex beat
• A flail segment
• In children, subcostal or intercostal recession and tracheal tug: indrawing of the elastic tissues caused by increased respiratory effort.

All the above suggest that the patient is struggling to achieve normal respiration. Failure to oxygenate the blood adequately and hence the tissues are shown by:

• Tachycardia: the nervous system has detected hypoxia and is stimulating the heart
• Pallor and sweating: caused by sympathetic stimulation
• Cyanosis: a late sign
• Irritability, confusion or reduced responsiveness: the brain is short of oxygen. This is an extremely worrying sign
• A low SaO2(<94%): pulse oximetry should be established as soon as possible

Allergic reactions p. 306.

Chest decompression and drainage p. 76.

Chest injuries p. 74.

Respiratory distress p. 205.

Oxygen therapy

The common denominator of most life-threatening illness, irrespective of cause, is the failure to deliver adequate amounts of oxygen to the tissues.

In the initial phase of assessment of the critically ill patient, high-flow...