Thoracic trauma
Many of the surgically treatable conditions of
the lung are treated at specialist thoracic centres and the only exposure to
thoracic surgery that most surgeons have is dealing with thoracic trauma. The
approach to treatment must be methodical and exact because the signs,
particularly in the presence of other injury, may easily be missed. The
guidelines produced by the American College of Surgeons Advanced Trauma Life
Support (ATLS®) Group provide a thorough and unambiguous approach to trauma.
The general principles of resuscitation and need for priorities are extensively
discussed and will not be repeated here. However, the specific aspects of trauma
management related to the thorax will be covered. Thoracic trauma is responsible
for over 70 per cent of all deaths following road traffic accidents. Blunt
trauma to the chest in isolation is fatal in 10 per cent of cases, rising to 30
per cent if other injuries are present. An increasing number of penetrating
thoracic wounds is also seen from domestic and civil violence, with a mortality
rate of 3 per cent for simple stabbing to 15 per cent for gunshot wounds.
Initial
management
Early deaths after thoracic trauma are caused
by hypoxemia, hypovolaemia and tamponade. The first steps in treating
The
basic principles of resuscitation are securing the airway and restoring the
circulating volume. Blood and secretions are removed from the oropharynx by
suction. If the patient is unable to maintain his or her airway then an
oropharyngeal airway followed by tracheal intubation (once a cervical spine
injury is excluded) may be necessary.
A
thorough inspection of the chest wall includes noting the frequency and pattern
of breathing, external evidence of trauma and structural defects of the thorax.
Palpation will detect surgical emphysema, paradoxical movement and a stove-in
chest. Auscultation and percussion should reveal the existence of a pneumothorax
(there is decreased movement on the affected side with a hyperresonant
percussion note, reduced breath sounds in the axilla and shift of the trachea to
the opposite side) which requires emergency drainage (see Pneumothorax for a
more detailed appraisal and see Chest drainage for advice on technique of drain
insertion).
Once
the patient has been stabilised then radiographs of the chest should be taken
and further treatment decided on the basis of the patient’s condition and the
radiographic result. It
is rarely necessary to perform a thoracotomy
in the resuscitation room but, in the case of tamponade from a penetrating
injury, it might be life saving. However, the fact is that, even in experienced
hands, the yield in terms of survival in this group of patients is very small.
If there is profound hypotension as a result of cardiac tamponade, needle
aspiration of the pericardium is life saving and may hold the situation long
enough for more controlled surgery to be performed.
The
components of chest injury in blunt trauma
Any combination of structures may be involved
in varying degrees of severity. If the skeletal injuries are severe, underlying
parenchymal injuries are likely to be in proportion; however, in young flexible
chests, or those restrained by seat belts, there may be little external evidence
of the severity of internal damage.
Chest wall
Localised rib fracture due to direct trauma. A
simple rib fracture may be serious in elderly people or in those with chronic
lung disease who have little pulmonary reserve. Uncomplicated fractures require
sufficient analgesia to encourage a normal respiratory pattern and effective
coughing. Oral analgesia may suffice but intercostal nerve blockade with local
anaesthesia may be very helpful. Chest strapping or bed rest is no longer
advised and early ambulation with vigorous physiotherapy (and oral antibiotics
if necessary) is encouraged. A chest radiograph is always taken to exclude an
underlying pneumothorax. It is useful to confirm the skeletal injuries but
routine chest radiography may miss rib fractures. However, once a pneumothorax
and major skeletal injuries are excluded, the management is the same — the
local control of chest pain.
Major
chest wall trauma. Flail chest (Fig.
47.1). This occurs when several adjacent ribs are fractured in two places either
on one side of the chest or either side of the sternum. The flail segment moves
paradoxically, that is, inwards during inspiration and outwards during
expiration, thereby reducing effective gas exchange. The net result is poor
First rib fracture. Fracture of the first rib should alert the clinician
to a potentially serious chest injury. This rib is well protected and requires a
considerable force to fracture and associated injuries to the great vessels,
abdomen, head and neck are common. The mortality rate associated with a fracture
of the first rib exceeds 30 per cent. Similar suspicions are raised when
fractures of the sternum and scapula are seen. Fractures of the lower ribs may
involve underlying abdominal viscera (spleen on the left and liver on the
right). Intercostal artery bleeding may still be severe, resulting in
haemothorax.
Fractures of the sternum (Fig. 47.2). This injury is now seen as a result of
deceleration on to seat belts. Steering wheel injuries are now much less common.
The injury is very painful even in the mild case where only the external plate
of the sternum is fractured. However, there is a real risk of underlying
myocardial damage and the patient should be observed in hospital with constant
electrocardiogram (ECG) monitoring, analgesia and serial cardiac enzymes.
Rupture of the aorta and associated cervical spine injuries also need to be
excluded. Most cases need no specific treatment but paradoxical movement or
instability of the chest may need more active management. It should be
remembered that sternal fracture may occur during closed cardiac massage.
Vertebrae. The thoracic spine may be injured as one component of multiple injury
or in isolation. It is more usual for the cervical spine to be injured and this
must be excluded before any manipulations or movements take place. Damage to the
thoracic spine is likely to be associated with injuries to other thoracic
viscera. The assessment and treatment of spinal injury are discussed in Chapter
33. However, the thoracic spine injury is a reminder that, in patients where the
chest injury predominates, a quick screening neurological examination confirming
the integrity of the nerve supply to the lower limbs should be performed and
documented.
Pleura. If the visceral pleura is breached (most commonly by a rib fracture)
pneumothorax follows. Generation of positive pressure in the airways by
coughing, straining, groaning
Traumatic
pneumothorax. Blunt trauma to the chest wall may result in a lung laceration
from a rib fracture. All traumatic pneumothoraces require drainage through an
underwater seal drain because of the possibility that they may become a
tension pneumothorax with mediastinal shift and circulatory collapse. There is
decreased air entry on the affected side and the trachea may be pushed over to
the opposite side. There is an increased percussion note and reduced breath
sounds. If a tension pneumothorax is suspected on clinical grounds, treatment is
necessary before radiographs can be taken. A wide-bore needle introduced into
the affected hemithorax will release any air under
Traumatic
haemothorax. Drainage is essential because reexpansion of the lacerated lung
compresses the torn vessels and reduces further blood loss. Drainage will also
allow the mediastinal structures to return to the midline and relieve
compression of the contralateral lung. If left, a dense fibrothorax will
result, with the possibility of an added empyema. The procedure is similar to
drainage for pneumothorax but a wide-bore rube (>28 Fr) is required and a
basal drain is sometimes necessary. Continuing blood loss in excess of 200
ml/hour may require urgent thoracotomy within the first few hours.
Lung parenchyma
Lung contusion. The underlying lung is often
injured in moderate-to-severe blunt thoracic trauma and the area of contusion
may be extensive. This usually resolves but lacerations with persistent air leak
may require exploration by thoracotomy. It is important to prevent
infection of the underlying lung by early mobilisation (if the patient’s
condition permits), prophylactic antibiotics, suction drainage and
physiotherapy. The importance of a good-quality posteroanterior erect chest
radiograph following any trauma to the lung cannot be overemphasised (Fig.
47.4).
Major airways
Injuries to major bronchi are infrequently
seen as the patient rarely survives the insult leading to major airway
disruption. There is usually a combination of surgical emphysema, haemoptysis
and pneumothorax. Chest drainage in spite of the addition of suction fails to
reinflate the lung and a persistent air leak may be present. Injury to the
trachea requires considerable force and consequently less than a quarter of
patients survive to reach hospital. The injury may be from direct trauma or the
result of high intratracheal
Diaphragm
Diaphragmatic rupture. The mechanism for
diaphragmatic rupture is high-speed blunt abdominal trauma with a closed
glottis. The sudden rise in intra-abdominal pressure breaches the weakest part
of the abdominal wall, namely the diaphragm. This occurs much more commonly on
the left hemidiaphragm (the right is protected by the liver). Colon and stomach
may herniate into the thorax, displacing the lung. Bowel sounds may be heard in
the chest and the chest radiograph may reveal bowel gas in the lung fields. A
contrast study will confirm the diagnosis. Occasionally, the injury is
overlooked and the patient presents some time later with a diaphragmatic hernia.
Cases presenting acutely should be explored by thoracotomy not only to repair
the diaphragm and prevent respiratory embarrassment, but to exclude injury to an
underlying abdominal viscus such as the spleen. Penetrating injuries below the
level of the eighth rib may penetrate the diaphragm and injure an underlying
abdominal viscus.
Oesophageal
injury
The oesophagus is rarely injured in blunt
trauma. The management of penetrating trauma to the oesophagus is discussed in
Chapter 50.
Cardiac injury
Major injuries to the heart and great vessels
from blunt trauma are frequently fatal and the patient rarely survives long
enough to reach hospital. The injuries that are encountered in the accident and
emergency department are the following.
Myocardial
contusion. This must be suspected when the sternum is fractured, although the
true incidence is not known. Myocardial damage from trauma will give an ECG
pattern similar to myocardial infarction and enzyme changes may occur. In severe
trauma there may be arrhythmias and signs of heart failure. Patients with ECG
changes and enzyme rises even in the absence of any problems should be nursed in
a high-dependence area with full monitoring and resuscitation equipment
available. There is no specific treatment in the uncomplicated case but the risk
of fatal arrhythmia diminishes after 48 hours or until the enzymes have returned
to normal and any ECG changes have resolved. Occlusion of the coronary arteries
progressing to discrete, localised myocardial infarction has been documented.
Chamber
rupture and valve blow-out. This is well described and is thought to occur if
the ventricle is
compressed just before systole at the point of
maximal diastolic filling. Chamber rupture is likely to be fatal and those that
do survive are likely to have an atrial rupture. Rupture of the mitral or
tricuspid valve may not be immediately apparent, but a loud pansystolic murmur
should arouse suspicion. Surgical treatment usually results in dramatic
improvement in these patients.
Aorta
Aortic transection (Fig. 47.5). This is usually the result of a major deceleration injury
(road traffic accident or a fall from a height) and the patient often has other
injuries. However, only about 15 per cent of patients with aortic transection
survive long enough to reach hospital. Of these, two-thirds would die of late
rupture within 14 days and the remainder
•
continued brisk bleeding (>100 mI/15 minutes) from the intercostal
drains indicates a serious breach of the lung parenchyma and urgent exploration
is required;
•
rupture of the bronchus, aorta, oesophagus or diaphragm;
•
cardiac tamponade (if needle aspiration is unsuccessful).
All explorations following trauma should have
double-lumen tube endotracheal intubation to facilitate surgery on the injured
side and to protect the undamaged lung.
If
transfer is undertaken, the patient must be
stabilised before the journey. All lines must be secured and ECG monitoring
available. Chest drains must not be
clamped during transfer and a medically qualified person should accompany the
patient.
Penetrating
injury
In some aspects, penetrating thoracic injury
is simpler to deal with than blunt trauma because the wound is visible and the
structures at risk can be quickly assessed. A defect in the chest wall through
to the pleura is a ‘sucking wound’. The underlying lung collapses and air
moves in and out of the thorax with each breath. Emergency treatment involves
sealing the wound and intercostal drainage. Definitive treatment may then
follow. It is important to establish the path or track of bullet and stab wounds
in the chest as there may be damage to the heart, great vessels, and the
diaphragm and abdominal viscera in addition to the lung injury.
They are bringing him down,
He looks at me wanly.
The bandages are brown,
Brown with mud, red only —But how deep a red
in the breast of the shirt,
Deepening red too, as each whistling breath
Is drawn with the suck of a slow filling
squirt
While
waxen cheeks waste to the pallor of death. From
Bullet
wounds create a cavitating defect in the tissues that they pass through. The
tissue damage may be very extensive with high-velocity missiles, and entry and
exit wounds should be noted. Lung tissue is more compliant than the bone and
muscles that comprise the limbs, and enthusiastic resection along the track
can be avoided in most cases. Tetanus prophylaxis and high-dose antibiotics (to
cover anaerobic organisms) should be given. Bullets lodged in the lung do not
require removal if they are not causing any problems.
Penetrating
wound of the heart
This is usually the result of a stabbing or
shooting incident, but can also be iatrogenic from central line placement,
cardiac catheterisation and endomyocardial biopsy. Cardiac tamponade may occur
rapidly even with small amounts of blood in the pericardium and the condition is
recognised by low blood pressure, tachycardia, a high central venous pressure,
pulsus paradoxus and faint heart sound (Fig. 47.7). Emergency treatment includes
aspiration of the pericardium by advancing a wide-bore needle to the left of the
xiphisternum towards the heart. This may hold the
situation until surgical repair is performed. The heart is exposed via a median
sternotomy with incision of the pericardium in the midline. For the more
generally trained surgeon or those without the necessary equipment to saw the
sternum, a left anterior thoracotomy may be preferred. The pericardial cavity is
evacuated and the cardiac defect repaired using buttressed sutures. Bullets in
cardiac chambers should be removed under cardiopulmonary bypass.
How
to do a thoracotomy
All surgeons dealing with trauma victims
should be able to perform a thoracotomy if required. The standard route into the
thoracic cavity is through a posterolateral thoracotomy. The incision is used
for access to:
•
the lung and major bronchi;
•
the thoracic aorta (aneurysm resection, repair of transection,
coarctation repair and ligation of patent ductus arteriosus);
•
the oesophagus (resection and repair);
•
the posterior mediastinum (for mediastinal mass resection).
Following induction of anaesthesia, a
preoperative rigid bronchoscopy is performed, especially if a resection for
cancer is contemplated. A double-lumen tube is used to control the lungs
separately, if desired. Ventilation may be maintained by ventilating one lung
while the other is collapsed to facilitate surgery. However, remember that they
were devised to protect the underlying lung from pus and blood, and to stay
under the anaesthetist’s control. The
The
incision is made from 1 to 2 cm inferolateral to the nipple in men and the
inframammary fold in women. The incision extends along 1—2 cm below the tip of
the scapula and extends posteriorly and superiorly between the medial border of
the scapula and the spine. The incision is deepened through the subcutaneous
tissues until the latissimus dorsi is met. This muscle is divided with
coagulating diathermy taking care over haemostasis. The line of division is the
same as for the skin. A plane of dissection is developed by hand under the
scapula and serratus anterior. The ribs can be counted down from the highest
palpable rib (which is usually the second) and the sixth rib periosteum is
scored with the diathermy near its upper border. A periosteal elevator is used
to lift the periosteum off the superior border of the rib. This reveals the
pleura which may be entered by blunt dissection. A rib spreader is inserted
between the ribs and opened gently to prevent fracture. Exposure may be
facilitated by dividing the rib at the costal angle or by dividing the
costotransverse ligament. Routine resection of a rib is an uncommon practice.
The anaesthetist is now able to deflate the affected lung to allow a better view
of the intrathoracic structures. In an emergency thoracotomy for penetrating
wounds of the heart, a more anterior approach is used and no specialised
supporting equipment is required (Fig. 47.9).
Large-calibre
(28—32 Fr) intercostal drains are usually inserted at the end of the
procedure. it is common practice to site them through the seventh or eighth
intercostal space anterior to the midaxillary line so that the patient does not
lie on them. For chronic management, such as closed drainage of empyema, the
drains are tunnelled to come out more anteriorly for easier management.
Traditionally, the more anteriorly sited drain goes to the apex and the
posteriorly placed drain goes to the lung base. A rib approximator is used to
realign the ribs and the stripped periosteum and intercostal muscle is sutured
to the intercostal muscle below the stripped rib using a continuous absorbable
suture. A nonabsorbable suture may be used to maintain the closure if healing is
likely to be compromised. The fascia and muscle layer are closed in layers using
an absorbable suture (Fig. 47.10). Skin closure is a matter of personal
preference.
Analgesia
is an important aspect of postoperative care and the process may be started
intraoperatively by infiltrating the intercostal nerves in the region of the
incision with a longacting local anaesthetic. Various strategies have been
developed to deliver analgesics postoperatively to facilitate a normal breathing
pattern.
Postoperative
care
Lung function is rarely assessed before urgent
thoracotomy for trauma but it is a vital part of the patient’s preoperative
work-up before elective thoracotomy. A description of lung function testing is
given in Appendix 2 at the end of this chapter. These patients have limited
respiratory reserve following lung resection, so infection and fluid overload
are to be avoided. Chest drains placed at the time of surgery drain blood
collections and cope with air leaks if present. Once the air leaks have settled
and any remaining lung is reexpanded, the drains are removed. Mobilisation,
breathing exercises and regular physiotherapy are begun as soon as the
patient’s condition permits.
Postoperative
pain
It is important to deal with post-thoracotomy
pain effectively so that a normal breathing pattern and gas exchange are
achieved in the early postoperative period. Patient-controlled analgesia is an
important development but still requires regular nursing and anaesthetic
supervision. Internally placed catheters delivering local anaesthetic into the
wound and beneath the pleura may also be effective. Long-term postthoracotomy
pain can be avoided by careful attention to detail during the operation. Sources
of avoidable chronic pain include rib fracture and entrapment of intercostal
nerves during wound closure.