Page 1638 - Hall et al (2015) Principles of Critical Care-McGraw-Hill

CHAPTER 120: Torso Trauma 1157

the endotracheal tube may be directed into the right mainstem bronchus clinically. The gas exchange abnormality is primarily due to the under-
and the cuff of the endotracheal tube inflated. This would allow ventila- lying lung contusion and not the flail per se. The degree of pulmonary
tion of the right lung until the left lung lesion has been repaired. In the and hemodynamic disability that arises is related to the extent of the
OR, a double-lumen tube, if available, will allow selective ventilation of flail, the degree of underlying lung contusion, and the restrictive effect
the normal lung. At surgery, the lesion is identified and repaired directly. of chest wall pain from the multiple fractures. There is, therefore, a wide
If there is massive destruction of the bronchus with failure to achieve an spectrum of presentation of patients with flail chest.
anastomosis or a high risk of subsequent stenosis, lung resection should In the severely hypoxemic patient with a large flail and/or hemo-
be considered. Successful thoracoscopic approaches for persistent air dynamic instability, immediate endotracheal intubation and positive-
leak have also been reported. pressure ventilation are indicated, with prompt chest tube insertion on
■ TRAUMATIC AIR EMBOLISM the involved side to prevent a tension pneumothorax from developing
on institution of positive-pressure ventilation. Patients who are able
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The exact incidence of this entity in patients with multiple injuries is to maintain adequate oxygenation and ventilation with supplemental
not known. However, to make the diagnosis, a very high index of sus- oxygen may be maintained without mechanical ventilation and endotra-
picion must be maintained, and this diagnosis should be suspected in cheal intubation, particularly if adequate pain control can be achieved.
any patient with sudden cardiovascular collapse who demonstrates a This may require frequent or continuous intravenous analgesia in the
neurologic deficit after chest injury, especially if these signs occur with form of titrated fentanyl, morphine, or other agents. In other circum-
the initiation of positive-pressure ventilation. In most cases, the diagno- stances, epidural or, less preferably, intercostal blockade with long-
sis of traumatic air embolism is made at thoracotomy that is conducted acting local anesthetic agents may be used to control the pain. With
on the basis of sudden collapse of a patient who has sustained major adequate analgesia, it is possible to avoid endotracheal intubation and
chest trauma. Occasionally, these patients may be quite stable initially, mechanical ventilation in most patients with flail chest.
only to develop a focal neurologic deficit suddenly with cardiovascular Emergency thoracotomy is not required for treating flail chest. Also,
collapse immediately after being placed on positive-pressure ventila- mechanical fixation of the rib fractures usually is not necessary. There
tion. Another sign suggestive of the diagnosis is the presence of bubbles is still controversy as to whether formal thoracotomy and mechanical
within arterial blood drawn by arterial puncture, usually for blood gas fixation of the fractured ribs should be considered at all in these patients.
analysis. It must be recognized, however, that the most common cause of However, in situations where thoracotomy is required for other reasons,
air bubbles in the syringe is a loosely fitting syringe connector; this must it may be appropriate to reduce and plate the fractures involved.
be ruled out prior to making the diagnosis. Occasionally, air may be seen If a decision is made to ventilate the patient with a flail chest, the
in the retinal arteries on funduscopic examination as well. timing of weaning will not necessarily depend on disappearance of the para-
An anterolateral thoracotomy should be performed on the side of doxical movement of the chest wall. Rather, weaning from the respirator
the penetrating injury or on the left side if no penetration is apparent. may be initiated when the gas exchange abnormality associated with the
On entry into the thoracic cavity, prevention of further embolization is underlying lung contusion is resolved. In fact, frequently these patients are
accomplished by cross-clamping the pulmonary hilum. An 18-gauge weaned completely off respiratory support (with adequate pain control)
needle should be used for venting the most anterior surfaces of the left when the lung contusion clears, even when residual paradoxical move-
atrium, left ventricle, and ascending aorta. This maneuver is followed by ment remains apparent for several weeks. A potential disadvantage of the
compressing the root of the aorta between the thumb and index finger, nonsurgical and conservative nonventilating approach to flail chest is the
which are placed in the transverse sinus. Massaging the heart should acceptance of a high degree of ultimate chest wall deformity. However,
drive air bubbles out of the coronary microvasculature. Maintenance these chest wall abnormalities are of questionable significance in terms of
of a high systemic blood pressure, with α agonists if necessary, should producing a long-term restrictive defect in these patients.
help to force trapped air from the heart and brain through the micro-
vasculature into the venous circulation. With reestablishment of cardiac EMERGENCY THORACOTOMY
activity, the left-sided chambers and the aorta should be vented once
more. Attention is then directed to the pulmonary lesion, which will Improvement in trauma response time and prehospital resuscitation
require repair by direct suture, lobectomy, or pneumonectomy as neces- have resulted in many patients arriving in the emergency room “in
sitated by the nature of the injury. extremis” with imminent cardiac arrest or with CPR in progress. There
■ FLAIL CHEST is thus an increasing role for thoracotomy in the emergency room as part
of trauma resuscitation.
completely discontinuous from the rest of the rib cage. It usually results ■ INDICATIONS
This condition arises whenever a portion of the chest wall becomes

from blunt chest trauma in which several adjacent ribs are fractured on Emergency room thoracotomy allows:
both sides of the sternum or, at least, at two locations on each of the
ribs involved. This leads to a free-floating segment of the chest wall that • Release of cardiac tamponade (especially in penetrating trauma)
positions itself in response to changes in pleural pressure rather than to • Control of massive intrathoracic hemorrhage
the mechanical positions of the rest of the chest wall. The result is para- • Intrathoracic cardiac massage especially in the hypovolemic patient
doxical movement of this portion of the chest wall. During spontaneous not responding to external cardiac massage
breathing, the flail segment moves inward with the negative pleural pres- • Thoracic aortic clamping for maintenance of perfusion to the heart
sure of inspiration and moves outward with expiration. The diagnosis and brain while controlling hemorrhagic sources distal to the tho-
frequently is missed initially if one relies entirely on the detection of racic aorta
paradoxical movement of the chest wall because muscle spasm and pain
restrict movement of the chest wall and make it very difficult to detect • Treatment of air embolism (Bronchovenous)
the posterior thorax, where the muscle mass makes it even more difficult ■ CARDIAC TAMPONADE
the paradoxical movement. This is particularly true in injuries involving
to detect paradoxical movement. Also, if the patient has been intubated The highest survival rate in emergency thoracotomy is from the treat-
and positive-pressure ventilation is instituted, paradoxical movement ment of cardiac tamponade secondary to a penetrating mechanism.
of the chest wall will not be seen. The presence of multiple adjacent The key elements are early recognition, prompt decompression of the
rib fractures involving the same rib in different segments on chest pericardial sac, and surgically correcting the source of the hemorrhage.
x-ray would suggest the presence of flail chest even if it is not apparent Utilization of FAST (Focused Assessment Sonogram in Trauma) allows

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