Moul_Ch01.qxd 4/7/06 2:39 PM Page 1
Chapter 1
The principles of emergency
medicine
People from many different backgrounds, with an If responsive, then the patient will usually be able
enormous variety of problems, present to an to elaborate on the cause of the sudden deteriora-
emergency department (ED) both by day and by tion that has brought him or her to an ED.
night. Fortunately, certain basic principles are Failure to respond indicates a significantly
applicable to the care of them all. 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
Immediate (or primary) assessment
manoeuvres and action to protect the airway.
and management of the patient
The priorities are as follows. In all cases, swift and Look, listen and feel for breathing
accurate assessment must immediately lead to The absence of breath sounds indicates the need
appropriate action. to attempt airway opening manoeuvres (see below)
For cardiac arrest protocols see page 156. and if unsuccessful to consider the possibility of a
For further details of immediate assessment and manage- foreign body obstruction.
ment of children see Chapter 18, page 323.
Foreign body obstruction may initially present as a
distressed, very agitated, cyanosed patient – ‘choking’.
A – Airway
For choking protocols see page 205.
The airway may be: For respiratory arrest see page 208.
● patent, partially obstructed or completely For cardiorespiratory arrest see Chapter 11, page 156.
obstructed (this results from physical obstruction If breathing is present then:
or loss of muscle tone); Look for the signs of partial upper airway
● adequately protected or at-risk (this depends on obstruction
the protective reflexes of the airway). ● Snoring – the familiar sound of obstruction
caused by the soft tissues of the mouth and phar-
Check for responsiveness ynx. Often it accompanies the reduced muscle
Is the patient alert and responsive to questions? tone of a lowered level of consciousness.
A verbal reply confirms that there is: ● Rattling or gurgling – the sound of fluids in the
● a maintained and protected airway; upper airway.
● temporarily adequate breathing and circulation; ● Stridor – a harsh, ‘crowing’ noise, which is
● cerebral functioning. heard best in inspiration. It is thus different from
1
,Moul_Ch01.qxd 4/7/06 2:39 PM Page 2
Chapter 1 The principles of emergency medicine
wheezing, which is usually loudest in expiration. Clearance and maintenance of the
Stridor suggests obstruction at the level of the airway
larynx and upper trachea. General illness and
A patent airway is a prerequisite for life; a blocked
temperature usually indicate an infection causing
airway is a common harbinger of death in emer-
swelling. Obstruction by a foreign body is the
gency situations. There are two main ways in
other main cause.
which the airway becomes blocked.
1 The most common cause of airway obstruction
In cases of suspected supraglottic swelling, examination
or instrumentation of the throat should not be carried is a depressed level of consciousness. The tone of
out for fear of causing complete obstruction. the muscles controlling the patency of the mouth
and the pharynx is under neural control in much
● Drooling – the inability to swallow saliva. It sug- the same way as is the activity of the other striated
gests blockage at the back of the throat. muscles of the body. When this control is lost the
● Hoarseness – gross voice change. This suggests soft tissues around the airway prolapse and fail to
obstruction at the level of the larynx. maintain its patency (simplistically, the tongue
falls back). This can be overcome by:
● tightening these tissues (chin lift manoeuvre);
Cyanosis and reduced haemoglobin saturation read-
● pushing the jaw and the hyoid bone and
ings on a pulse oximeter are very late signs of airway
obstruction. their attached soft tissues forward (jaw thrust
manoeuvre);
● putting an artificial airway down the anatom-
For clearance and protection of the airway see below.
For laryngotracheal obstruction see page 205. ical airway (oro- or naso-pharyngeal airways,
For allergic reactions see page 295. endotracheal tubes, laryngeal masks, etc., see
For surgical airways see page 23. Figure 1.1).
2 The other way that the airway becomes blocked
is by physical obstruction. Many things can do this
Assess the need for cervical spine protection before any
airway intervention. (direct trauma, external or intramural mass, etc.)
However, in emergency practice, there is usually
Epiglottis Vocal cord
Ventricular
fold
Trachea
Arytenoid
Aryepiglottic
cartilage
fold
Figure 1.1 Visualisation of the larynx.
2
, Moul_Ch01.qxd 4/7/06 2:39 PM Page 3
The principles of emergency medicine Chapter 1
either something in the airway (vomitus, blood or the soft tissues to be positioned in such a way that
foreign body) or there is swelling in the wall of the they do not cause obstruction. Once the airway is
airway (oedema, haematoma, etc.). This is over- clear, this position can be used to both maintain
come by: and protect the airway.
● removing the cause of the obstruction (suc- ● A high-flow suction catheter must always be
tion, manual removal or choking manoeuvres); near the patient’s head.
● passing an artificial airway (as detailed above) ● The patient’s trolley must be capable of tilting
past the obstruction; “head down” so as to drain vomitus out of the
● reducing the swelling with vasoconstrictor airway.
drugs (adrenaline); ● If endotracheal intubation is attempted, the air-
● bypassing the obstruction with a surgical way must be protected by the manoeuvre known
airway. as cricoid pressure throughout the period of
instrumentation. Pressure is applied to the front of
the patient’s cricoid cartilage by an assistant using
Protection of the airway
the thumb and two fingers. This compresses the
The airway is normally kept clear of foreign matter oesophagus against the cervical spine and thus
by the gag, cough and laryngeal reflexes. These prevents the passive regurgitation of gastric con-
may be attenuated by specific palsies, the effects tents. The airway is vulnerable from the start of
of drugs or a generalised depression of conscious induced paralysis until the cuff is inflated on a
level. They may also be impaired at the extremes correctly positioned endotracheal tube.
of age and in states of general debilitation. Special
vigilance is required in all such situations;
Protection of the cervical spine
the recovery position should be used whenever
possible. If the patient has an injury to the cervical spine,
Paradoxically, these same reflexes may make there is a risk of damage to the spinal cord during
advanced airway care extremely difficult in situa- the procedures needed to maintain the airway.
tions where they are not completely absent. Because of the terrible outcome of such damage, it
At such times, the airway should be managed by a is mandatory to protect the neck immediately in
person skilled in both its assessment and the use patients who are:
of sedating and paralysing drugs. 1 unresponsive with a history of trauma or no
clear history;
Over 10% of normal subjects have no gag reflex. 2 suffering from multiple trauma;
3 difficult to assess;
Laryngospasm, bleeding, vomiting and conse- 4 showing any symptoms or signs that might be
quent hypoxia can result from ill-judged attempts attributable to the cervical spine.
at intubation. It should be noted that the absence Adequate protection of the potentially unstable
of the gag reflex is not a good predictor of the cervical spine consists of a rigid collar and either a
need for (or the ease of) endotracheal intubation. purpose-made cervical immobiliser or sandbags
and tape.
In a patient with a reduced level of consciousness, the For exclusion of cervical spine injury see page 57.
airway must be assumed to be at-risk until proved
otherwise.
B – Breathing
On-going protection of the airway requires con- Breathing is the means by which oxygen is deliv-
tinual vigilance. The following are also essential: ered to the alveoli and thus made available to
● The recovery position uses gravity, both to drain the circulating red cells. At the same time carbon
fluid matter away from the airway and to allow dioxide (CO2) is eliminated.
3
Chapter 1
The principles of emergency
medicine
People from many different backgrounds, with an If responsive, then the patient will usually be able
enormous variety of problems, present to an to elaborate on the cause of the sudden deteriora-
emergency department (ED) both by day and by tion that has brought him or her to an ED.
night. Fortunately, certain basic principles are Failure to respond indicates a significantly
applicable to the care of them all. 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
Immediate (or primary) assessment
manoeuvres and action to protect the airway.
and management of the patient
The priorities are as follows. In all cases, swift and Look, listen and feel for breathing
accurate assessment must immediately lead to The absence of breath sounds indicates the need
appropriate action. to attempt airway opening manoeuvres (see below)
For cardiac arrest protocols see page 156. and if unsuccessful to consider the possibility of a
For further details of immediate assessment and manage- foreign body obstruction.
ment of children see Chapter 18, page 323.
Foreign body obstruction may initially present as a
distressed, very agitated, cyanosed patient – ‘choking’.
A – Airway
For choking protocols see page 205.
The airway may be: For respiratory arrest see page 208.
● patent, partially obstructed or completely For cardiorespiratory arrest see Chapter 11, page 156.
obstructed (this results from physical obstruction If breathing is present then:
or loss of muscle tone); Look for the signs of partial upper airway
● adequately protected or at-risk (this depends on obstruction
the protective reflexes of the airway). ● Snoring – the familiar sound of obstruction
caused by the soft tissues of the mouth and phar-
Check for responsiveness ynx. Often it accompanies the reduced muscle
Is the patient alert and responsive to questions? tone of a lowered level of consciousness.
A verbal reply confirms that there is: ● Rattling or gurgling – the sound of fluids in the
● a maintained and protected airway; upper airway.
● temporarily adequate breathing and circulation; ● Stridor – a harsh, ‘crowing’ noise, which is
● cerebral functioning. heard best in inspiration. It is thus different from
1
,Moul_Ch01.qxd 4/7/06 2:39 PM Page 2
Chapter 1 The principles of emergency medicine
wheezing, which is usually loudest in expiration. Clearance and maintenance of the
Stridor suggests obstruction at the level of the airway
larynx and upper trachea. General illness and
A patent airway is a prerequisite for life; a blocked
temperature usually indicate an infection causing
airway is a common harbinger of death in emer-
swelling. Obstruction by a foreign body is the
gency situations. There are two main ways in
other main cause.
which the airway becomes blocked.
1 The most common cause of airway obstruction
In cases of suspected supraglottic swelling, examination
or instrumentation of the throat should not be carried is a depressed level of consciousness. The tone of
out for fear of causing complete obstruction. the muscles controlling the patency of the mouth
and the pharynx is under neural control in much
● Drooling – the inability to swallow saliva. It sug- the same way as is the activity of the other striated
gests blockage at the back of the throat. muscles of the body. When this control is lost the
● Hoarseness – gross voice change. This suggests soft tissues around the airway prolapse and fail to
obstruction at the level of the larynx. maintain its patency (simplistically, the tongue
falls back). This can be overcome by:
● tightening these tissues (chin lift manoeuvre);
Cyanosis and reduced haemoglobin saturation read-
● pushing the jaw and the hyoid bone and
ings on a pulse oximeter are very late signs of airway
obstruction. their attached soft tissues forward (jaw thrust
manoeuvre);
● putting an artificial airway down the anatom-
For clearance and protection of the airway see below.
For laryngotracheal obstruction see page 205. ical airway (oro- or naso-pharyngeal airways,
For allergic reactions see page 295. endotracheal tubes, laryngeal masks, etc., see
For surgical airways see page 23. Figure 1.1).
2 The other way that the airway becomes blocked
is by physical obstruction. Many things can do this
Assess the need for cervical spine protection before any
airway intervention. (direct trauma, external or intramural mass, etc.)
However, in emergency practice, there is usually
Epiglottis Vocal cord
Ventricular
fold
Trachea
Arytenoid
Aryepiglottic
cartilage
fold
Figure 1.1 Visualisation of the larynx.
2
, Moul_Ch01.qxd 4/7/06 2:39 PM Page 3
The principles of emergency medicine Chapter 1
either something in the airway (vomitus, blood or the soft tissues to be positioned in such a way that
foreign body) or there is swelling in the wall of the they do not cause obstruction. Once the airway is
airway (oedema, haematoma, etc.). This is over- clear, this position can be used to both maintain
come by: and protect the airway.
● removing the cause of the obstruction (suc- ● A high-flow suction catheter must always be
tion, manual removal or choking manoeuvres); near the patient’s head.
● passing an artificial airway (as detailed above) ● The patient’s trolley must be capable of tilting
past the obstruction; “head down” so as to drain vomitus out of the
● reducing the swelling with vasoconstrictor airway.
drugs (adrenaline); ● If endotracheal intubation is attempted, the air-
● bypassing the obstruction with a surgical way must be protected by the manoeuvre known
airway. as cricoid pressure throughout the period of
instrumentation. Pressure is applied to the front of
the patient’s cricoid cartilage by an assistant using
Protection of the airway
the thumb and two fingers. This compresses the
The airway is normally kept clear of foreign matter oesophagus against the cervical spine and thus
by the gag, cough and laryngeal reflexes. These prevents the passive regurgitation of gastric con-
may be attenuated by specific palsies, the effects tents. The airway is vulnerable from the start of
of drugs or a generalised depression of conscious induced paralysis until the cuff is inflated on a
level. They may also be impaired at the extremes correctly positioned endotracheal tube.
of age and in states of general debilitation. Special
vigilance is required in all such situations;
Protection of the cervical spine
the recovery position should be used whenever
possible. If the patient has an injury to the cervical spine,
Paradoxically, these same reflexes may make there is a risk of damage to the spinal cord during
advanced airway care extremely difficult in situa- the procedures needed to maintain the airway.
tions where they are not completely absent. Because of the terrible outcome of such damage, it
At such times, the airway should be managed by a is mandatory to protect the neck immediately in
person skilled in both its assessment and the use patients who are:
of sedating and paralysing drugs. 1 unresponsive with a history of trauma or no
clear history;
Over 10% of normal subjects have no gag reflex. 2 suffering from multiple trauma;
3 difficult to assess;
Laryngospasm, bleeding, vomiting and conse- 4 showing any symptoms or signs that might be
quent hypoxia can result from ill-judged attempts attributable to the cervical spine.
at intubation. It should be noted that the absence Adequate protection of the potentially unstable
of the gag reflex is not a good predictor of the cervical spine consists of a rigid collar and either a
need for (or the ease of) endotracheal intubation. purpose-made cervical immobiliser or sandbags
and tape.
In a patient with a reduced level of consciousness, the For exclusion of cervical spine injury see page 57.
airway must be assumed to be at-risk until proved
otherwise.
B – Breathing
On-going protection of the airway requires con- Breathing is the means by which oxygen is deliv-
tinual vigilance. The following are also essential: ered to the alveoli and thus made available to
● The recovery position uses gravity, both to drain the circulating red cells. At the same time carbon
fluid matter away from the airway and to allow dioxide (CO2) is eliminated.
3
