Diseases
of the larynx
Emergencies
Stridor
Stridor means noisy breathing. It may be inspiratory or expiratory or
occurring in both phases of respiration. Inspiratory stridor is usually due to
an obstruction at or above the vocal folds and most commonly is a result of an
inhaled foreign body or acute infection such as epiglottitis. Expiratory stridor
is usually from the lower respiratory tract and gives rise to a prolonged
expiratory wheeze. It is most commonly associated with acute asthma or acute
infective tracheobronchitis. Biphasic stridor is usually due to obstruction or
disease of the tracheobronchial airway and distal lungs.
Stridor
in children (Table 43.7)
Infants and children presenting with stridor need assessment with a full
history and careful examination if appropriate. If on presentation a child is
cyanosed and severely unwell the airway must be secured as soon as possible but
it is often possible to obtain a brief history from the parents, with important
pointers. A nurse or colleague may be derailed to do this whilst the
resuscitation is taking place.
History.
In infants in the first year of life it is important to establish whether the
stridor is associated with particular activities such as swallowing, crying or
movement. These may suggest congenital laryngomalacia or subglottic stenosis. If
the stridor is exacerbated by feeding, particularly in the first 4 weeks of
life, this suggests a vascular ring or tracheooesophageal fistula. If the cry
is weak or abnormal this -suggests a vocal fold palsy. If the problem only
occurs in association with an upper respiratory tract infection and, in
particular, is biphasic this would suggest congenital subglottic stenosis. In a
young child inspiratory stridor and drooling suggest acute epiglottitis, whereas
biphasic stridor without drooling suggests laryngotracheobronchitis or croup.
Examination.
Observe the child carefully at rest; do not attempt to move or handle
the child, particularly if the stridulous child is being held by its mother or
other family member.
If a child is stridulous and drooling and sitting upright in its
mother’s arms or chair do not attempt to lie it down and do not attempt to
look inside the mouth.
Investigation. In addition to the oximeter,
plain lateral X-rays of the neck and a chest X-ray can be obtained but only if
the child’s condition permits. If the child is severely stridulous they should
not be sent to an X-ray department without access to medical staff or
resuscitation equipment. The X-rays may confirm the presence of a foreign body
or show soft-tissue shadowing consistent with a retropharyngeal or
parapharyngeal abscess, acute epiglottitis or chest disease.
Examination
under anaesthesia.
Examination under anaesthesia is essential in all children whose
diagnosis remains in doubt.
Equipment
should be available at all times to undertake an urgent tracheostomy to
establish or maintain an airway.
Acute
epiglottitis (Table 43.7)
This illness may occur in adults, although fortunately the stridor
rarely progresses as rapidly as in children. In children it is of rapid onset
and tends to occur in children of 2 years of age or over. Stridor is usually
associated with drooling of saliva. The condition is caused by Haemophilus
influenzae infection which initially causes a severe pharyngitis at the
junction of the oropharynx and hypopharynx before progressing to produce
inflammation and oedema of the laryngeal inlet. As it progresses it actually
involves the whole of the supraglottic larynx, with severe oedema of the
ariepiglottie
folds and epiglottis being the most notable component; hence the commonly used
term ‘acute epiglottitis’. Examination and investigation are outlined
above, but these children frequently require intensive management with emergency
intubation or tracheostomy followed by oxygenation, humidification, continuous
oximetry and antibiotics such as ampicillin or chloramphenicol to combat the
haemophilus infection. This may be associated with septicaemia and blood
cultures should be obtained.
any respiratory arrest.
Laryngotracheobronchitis
(croup)
This is usually of slower onset in contrast to acute epiglottitis and
occurs most commonly in children under 2 years of age. It is usually viral in
origin and the cases often occur in clusters. The children have a biphasic
stridor and often hoarseness, and a typical barking cough. Airway intervention
is required less often but admission to hospital with oxygenation and
humidification coupled with antibiotics may be necessary if there are signs of
secondary infection.
Foreign
bodies
Both children and adults may inhale foreign bodies. Young children will
attempt to swallow a wide variety of objects, but coins, beads and parts of toys
are particularly common. In adults the aspiration is usually of food,
particularly inadequately chewed bones and meat. This is more common in
elderly edentulous adults and occasionally portions of dentures may be inhaled,
particularly in association with road traffic accidents.
Clinical
features. The history is often paramount and it is important to always believe
the patient, particularly a parent who gives a history of foreign body ingestion
or inhalation in a child, even though the pain, dysphagia, coughing, etc., may
have settled. Adult patients will, on the whole, have a clear recall and the
diagnosis is more easy, but this may not always be the case particularly if the
patient is suffering from mental illness. Fish bones may lodge in the tonsils or
base of tongue with minimal symptoms but in certain areas of the world, notably
Asia, small fish bones may impact in the tonsils, oropharynx or hypopharynx and
give rise to parapharyngeal and retropharyngeal abscess formation.
Examination.
Examination may be prevented by trismus, pain and anxiety, but the presence of a
foreign body may be suspected by a salivary pool within the piriform fossa or
adjacent oedema and erythema of the pharyngolaryngeal mucosa.
Radiology.
Radiology
may be helpful but is not critical. Fish hones are often not visible on plain
X-rays, and a normal plain X-ray does not exclude a foreign body within the
pharynx, larynx, oesophagus or lungs.
Treatment. In the case of an inhaled foreign body causing severe stridor in a neonate or infant it may be removed either by hooking it from the pharynx with a finger or by inverting the child carefully by its ankles and slapping its back. In a larger child it may be more appropriate to bend them over your knee with their head hanging down and again strike them firmly between the shoulders. In the case of adults an impacted laryngeal foreign body may he coughed out in association with a Heimlich manoeuvre. This involves standing behind the patient, clasping the arms around the lower thorax such that the knuckles of the clasped hands come into contact with the patient’s xiphisternum, and then a brief firm compression of the lower thorax may aid instant expiration of the foreign body.
If
less urgent cases, if the radiography is not useful but a foreign body is
strongly suspected, then detailed endoscopy under general anaesthesia may be
indicated.
Choice
of operation
• The degree of urgency in establishing tracheostomy will determine the method used, but preference should always be for the elective procedure. One of the most appropriate pieces of advice in surgery is ‘the time to do a tracheostomy is when you first think it may be necessary’. All of the potential complications of tracheostomy are markedly decreased if a meticulous elective procedure is performed under controlled circumstances by an experienced team
If
time allows the following should be undertaken:
• indirect or direct laryngoscopy;
• tomography of the larynx and
upper trachea;
• assessment of pulmonary function.
• Whenever possible the procedure should be adequately explained to the
patient beforehand, with particular emphasis on the inability to speak
immediately following the operation and possible difficulties with swallowing.
Emergency
tracheostomy. If a skilled anaesthetist is unavailable local anaesthesia is
employed, but in desperate cases where the patient is unconscious none is
required. The only word of warning would be in those patients who have suffered
severe head and neck trauma, and may have an unstable cervical spine fracture.
Cricothyroidotomy may be more suitable under these circumstances.
If
it is possible the patient should he laid supine with padding placed under the
shoulders and the extended neck kept as steady as possible in the midline. This
aids palpation of the thyroid and cricoid cartilage between the thumb and index
finger of the free hand. The movements of the fingers of the free hand are
important in this technique. The operation is more difficult in small children
and thick-necked adults as the landmarks are difficult to palpate.
A
vertical midline incision should be made from the inferior aspect of the thyroid
cartilage to the suprasternal notch and continued down between the infrahyoid
muscles (Fig. 43.32). There may he heavy bleeding from the wound at this point,
particularly if the neck is congested as a result of the patient’s effort to
breathe around an acute upper airway obstruction. No steps should be taken to
control this haemorrhage, although an assistant and suction apparatus are
valuable if available. The operator should feel carefully, and without undue
haste, for the cricoid cartilage using the index finger of the free hand whilst
retracting the skin edges by pressure applied by the thumb and middle finger. If
the situation is one of extreme urgency a further vertical incision straight
into the trachea at the level of the second, third and fourth ring should be
made immediately without regard to the presence of the thyroid isthmus (Fig.
43.33). The knife blade is rotated through 900 thus opening the trachea. At this
point the patient may cough violently as blood enters the airway. The operator
should be aware of this possibility and avoid losing the position of the scalpel
in the open trachea. Any form of available tube should be inserted into the
trachea as soon as possible and blood and secretion sucked our. Once an airway
has been established haemostasis is then
Should
additional equipment and more time be available once the cricoid cartilage has
been identified, blunt finger dissection inferiorly can be used to mobilise the
thyroid isthmus which should be divided between haemostats, clearing the
trachea before making a vertical incision through the second—fourth rings. A
tracheal dilator should be inserted through the tracheal incision and the edges
of the tracheal wound separated gently. In cases of suspected HIV infection or
diphtheria the surgeon should place a swab over the wound so that the violent
expiratory efforts which may follow do nor contaminate the operator(s) with
infected mucus and blood. When respiratory efforts have become less violent a
tracheostomy tube should be inserted into the trachea and the dilator removed.
It is important that the surgeon keeps a finger on the tube while the assistant
ties the attached rapes round the patient’s neck.
Tracheostomy
tubes. These are basically made of two materials, silver or plastic (Fig.
43.39). Both materials have been used to make tubes of various sizes with
varying curves, angles, cuffs, inner tubes and speaking valves. A cuffed tube is
used initially, which may be changed after 3—4 days to a noncuffed plastic or
silver tube. The pressure within the tube cuff should be carefully monitored and
should be low enough not to occlude circulation in the mucosal capillaries. When
in position the tube should be retained by double tapes passed around the
patient’s neck with a reef knot on either side. It is important that the
patient’s head is flexed when the tapes are tied otherwise they may become
slack when the patient is moved from the position of extension, thereby
resulting in a possible displacement of the tube if the patient coughs.
Alternatively, the flanges of the plastic tube may be stitched directly to the
underlying neck skin.
Knowledge
of the physiological changes induced by tracheostomy is an essential
requirement for the understanding of postoperative management. All forms of
tracheostomy and cricothyroidotomy bypass the upper airway and have the
following advantages:
• the anatomical dead space is reduced by approximately 50 per cent;
• the work of breathing is reduced;
• alveolar ventilation is increased;
• the level of sedation needed for patient comfort is decreased and,
unlike endotracheal intubarion, the patient may be able talk and eat with a tube
in place.
• loss of heat and moisture exchange performed in the upper
respiratory tract;
• desiccation of tracheal
epithelium, loss of ciliated cells and metaplasia;
•
the increased mucus is more viscid, and thick crusts may form and block
the tube, particularly in children;
•
whilst many patients with a tracheostomy can feed satisfactorily, there
is some splinting of the larynx which may prevent normal swallowing and lead to
aspiration. This aspiration may he ‘silent’, i.e. nor apparent.
.
Fibre-optic endotracheal
intubation. In most emergency
situations endotracheal intubation is the most direct and satisfactory method of
securing the airway. Nasotracheal intubation in expert hands is also a
well-established technique and is particularly useful if the patient has
trismus,
severe mandibular injuries, cervical spine rigidity or an obstructing mass
within the oral cavity. Both of these forms of intubation can be aided in
difficult patients by passing a modern fibre-optic endoscope through the centre
of an endotracheal tube, hence guiding it into the larynx and trachea under
direct vision (Fig. 43.40).
Transtracheal
ventilation. This technique has been
increasingly advocated in the last decade and, although some specialist
equipment is required, the actual technique is simple and effective. It will
allow ventilation of the patient for periods in excess of 1 hour and will often
give ample time to
The
cricothyroid membrane is located by palpation of the neck with the index finger,
and a 14G or 16G plastic-sheathed intravascular needle and a 10-ml syringe
containing a few millilitres of lignocaine are introduced in the midline and
directed downwards and backwards into the tracheal lumen (Fig.
43.41). The
needle is advanced steadily and negative pressure is placed on the syringe until
bubbles of air are clearly seen. The tissues of the neck may be infiltrated with
the anaesthetic if desired and the tracheal mucosa likewise partly anaesthetised
by the introduction of 1—2 ml after gaining the lumen. The needle is removed
and the plastic-sheath cannula remains in the trachea. It is attached by means
of a Luer connection to the high-pressure oxygen supply. Ventilation may be
undertaken in a controlled manner with a jetting device with the chest being
observed for appropriate movements. If there is severe obstruction of the
laryngopharynx by the foreign body or tumour, the exhaled outflow of gases can
be aided by placement of one or two further cannulae as exhalation ports. This
procedure gains extremely rapid control of ventilation and requires a minimum of
technical expertise.
Ciricothyroidotomy.
Cricothyroidotomy has gained increasing support in some centres and is
advocated when endotracheal intubation is not possible. It has the advantages
of speed and ease requiring little equipment and surgical expertise. However,
its use for all but the briefest access to the airway remains controversial, and
there are conflicting reports with regard to the subsequent incidence of
complications, particularly those of subglottic stenosis and long-term voice
changes.
The
patient’s neck is extended and the area between the prominence of the thyroid
cartilage and the cricoid cartilage below is palpated with the index finger of
the free hand. In the emergency situation a vertical skin incision is recommended
with dissection rapidly carried down to the
Depending
on the degree of emergency it may be necessary for the surgeon to assess the
results of the procedure by direct laryngoscopy, and the authors recommend that
careful consideration should be given to conversion of the cricothyroidotomy to a tracheostomy. Although there is debate about the
frequency of subglottic stenosis following this procedure, there is general
agreement that it is much increased if any long-term ventilation is undertaken
via even a modest size tracheostomy tube through the cricothyroid membrane.