Page 301 - Critical Care Nursing Demystified

286 CRITICAL CARE NURSING DeMYSTIFIED

A hemothorax is caused by blood building up between the lung and the
pleural space from blunt or penetrating trauma. The hemothorax is usually
limited in expansion due to the tight space where it occurs. Rib fractures, con-
tusion, and venous injuries are usual causes of a hemothorax. If the hemothorax
is large, hypoxia from blood preventing alveolar oxygenation, possible airway
clearance issues, and hemorrhage can result.
A pneumothorax is a lung collapse due to either blunt or penetrating trauma.
When the lung is punctured from a rib or blunt trauma, the negativity in the
intrapleural space is compromised, resulting in either a total or partial collapse
of the lung on the traumatized side. A pneumothorax may be closed where
there is no connection to the outside environment, as with many blunt chest
traumas, or it may be open where outside air is drawn into the lung during
inspiration (sucking chest wounds). If unrelieved pressure enters the lung and
it does not escape back out, a tension pneumothorax may develop. This is a
life-threatening emergency. Whether open or closed, a pneumothorax leads to
less functioning alveolar oxygenation in the area that has collapsed. The higher
the percentage of pneumothorax, the more likely that hypoxemia can occur.
For more information on a pneumothorax please consult Chapter 2.
A tension pneumothorax is created when air becomes trapped in the chest Downloaded by [ Faculty of Nursing, Chiangmai University 5.62.158.117] at [07/18/16]. Copyright © McGraw-Hill Global Education Holdings, LLC. Not to be redistributed or modified in any way without permission.
with no avenue of escape. As pressure builds up, the highly moveable structures
in the mediastinum become pushed away from the affected side. The compro-
mised lung cannot participate in oxygenation, leading to hypoxemia. The heart
and great vessels become compressed, preventing blood from entering and leav-
ing the heart. Profound drops in cardiac output result. (See Table 6–6 for signs/
symptoms of the lung injuries)

Prognosis
The prognosis of all lung injuries is dependent on how quickly the patient is
diagnosed and treated. Pulmonary contusion plays a very large role in whether
an individual will succumb or suffer serious effects. It is estimated that contu-
sion occurs in 30% to 75% of severe chest injuries with a mortality rate that
varies greatly between 15% and 40%.
Patients with lung contusions must be followed up closely due to the high rate
of post-accident ARDS (see Chapter 2 for further information on ARDS).

Interpreting Laboratory Results
Chest x-ray will show pneumothorax (air or collapsed lungs) and hemotho-
rax (whiter color) over 20%.
CT scan is very sensitive for pulmonary contusion.