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Occult pneumothorax, revisited.

Omar HR, Abdelmalak H, Mangar D, Rashad R, Helal E, Camporesi EM - J Trauma Manag Outcomes (2010)

Bottom Line: Pneumothorax is a recognized cause of preventable death following chest wall trauma where a simple intervention can be life saving.However, in certain patients, especially those on mechanical ventilation (with subsequent increase of intrapleural air with positive pressure ventilation), missing the diagnosis of pneumothorax can be deleterious with fatal consequences.Because a negative AP chest radiograph can dangerously delay its recognition, we recommend that any trauma victim presenting to the emergency department with symptoms of respiratory distress should be screened with either thoracic ultrasonography or chest CT scan to avoid missing a pneumothorax.

View Article: PubMed Central - HTML - PubMed

Affiliation: Departement of Internal Medicine, Mercy Hospital and Medical Center, Chicago, Illinois, USA. hesham_omar2003@yahoo.com.

ABSTRACT
Pneumothorax is a recognized cause of preventable death following chest wall trauma where a simple intervention can be life saving. In cases of trauma patients where cervical spine immobilization is mandatory, supine AP chest radiograph is the most practical initial study. It is however not as sensitive as CT chest for early detection of a pneumothorax. "Occult" pneumothorax is an accepted definition of an existing but usually a clinically and radiologically silent disturbance that in most patients can be tolerated while other more urgent trauma needs are attended to. However, in certain patients, especially those on mechanical ventilation (with subsequent increase of intrapleural air with positive pressure ventilation), missing the diagnosis of pneumothorax can be deleterious with fatal consequences. This review will discuss the occult pneumothorax in the context of 3 radiological examples, which will further emphasize the entity. Because a negative AP chest radiograph can dangerously delay its recognition, we recommend that any trauma victim presenting to the emergency department with symptoms of respiratory distress should be screened with either thoracic ultrasonography or chest CT scan to avoid missing a pneumothorax.

No MeSH data available.


Related in: MedlinePlus

AP chest X-ray revealing evidence of bilateral lung contusions and left subcutaneous emphesema (Panel A). Chest CT confirmed both the lung contusions and the subcutaneous emphesema and demonstrated a left sided pneumothorax not initially appearing on the anteroposterior chest Xray (Panel B).
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Figure 2: AP chest X-ray revealing evidence of bilateral lung contusions and left subcutaneous emphesema (Panel A). Chest CT confirmed both the lung contusions and the subcutaneous emphesema and demonstrated a left sided pneumothorax not initially appearing on the anteroposterior chest Xray (Panel B).

Mentions: Yes, there are several clinical markers that can predict for an increased incidence of pneumothorax even if not detected on the initial anteroposterior chest radiograph. These markers should be well known to emergency and ICU physicians for early suspecting the diagnosis. A level III retrospective study [20] with a purpose to determine the incidence, predictors, and outcomes for occult pneumothorax after trauma concluded that the presence of subcutaneous emphysema, pulmonary contusions, rib fractures and female sex were crudely associated with the presence of occult pneumothorax with an odds ratio of 5.47 for subcutaneous emphesema, 3.25 for pulmonary contusions and 2.65 for rib fractures. Although only 16% of patients with occult pneumothorax had subcutaneous emphysema, 98% of the patients with subcutaneous emphysema had an underlying pneumothorax whether overt (82%) or occult (16%). Therefore subcutaneous emphesema has a very high specificiy for diagnosis of occult pneumothorax but its absence is insufficient to rule out the diagnosis. Four years later, on a subsequent prospective level-II study [12] performed by the same group, only subcutaneous emphysema remained the only independent risk factor that can predict occult pneumothorax. Other risk factors including patient's age, mechanism of injury, intubation status in the emergency department, seat belt use, GCS score and the presence of pre-exisisting pulmonary comorbidities showed no significant predictive value for occult pneumothorax. We suggest that any trauma patient presenting with subcutaneous emphesema, pulmonary contusion or rib fractures should be further evaluated with CT chest to exclude any underlying pneumothorax not visible on the regular chest radiograph. Figure 2 well demonstrates the predictability of occult pneumothorax. The presence of lung contusions and subcutaneous emphesema has prompted further evaluation with CT chest, which revealed a pneumothorax.


Occult pneumothorax, revisited.

Omar HR, Abdelmalak H, Mangar D, Rashad R, Helal E, Camporesi EM - J Trauma Manag Outcomes (2010)

AP chest X-ray revealing evidence of bilateral lung contusions and left subcutaneous emphesema (Panel A). Chest CT confirmed both the lung contusions and the subcutaneous emphesema and demonstrated a left sided pneumothorax not initially appearing on the anteroposterior chest Xray (Panel B).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2984474&req=5

Figure 2: AP chest X-ray revealing evidence of bilateral lung contusions and left subcutaneous emphesema (Panel A). Chest CT confirmed both the lung contusions and the subcutaneous emphesema and demonstrated a left sided pneumothorax not initially appearing on the anteroposterior chest Xray (Panel B).
Mentions: Yes, there are several clinical markers that can predict for an increased incidence of pneumothorax even if not detected on the initial anteroposterior chest radiograph. These markers should be well known to emergency and ICU physicians for early suspecting the diagnosis. A level III retrospective study [20] with a purpose to determine the incidence, predictors, and outcomes for occult pneumothorax after trauma concluded that the presence of subcutaneous emphysema, pulmonary contusions, rib fractures and female sex were crudely associated with the presence of occult pneumothorax with an odds ratio of 5.47 for subcutaneous emphesema, 3.25 for pulmonary contusions and 2.65 for rib fractures. Although only 16% of patients with occult pneumothorax had subcutaneous emphysema, 98% of the patients with subcutaneous emphysema had an underlying pneumothorax whether overt (82%) or occult (16%). Therefore subcutaneous emphesema has a very high specificiy for diagnosis of occult pneumothorax but its absence is insufficient to rule out the diagnosis. Four years later, on a subsequent prospective level-II study [12] performed by the same group, only subcutaneous emphysema remained the only independent risk factor that can predict occult pneumothorax. Other risk factors including patient's age, mechanism of injury, intubation status in the emergency department, seat belt use, GCS score and the presence of pre-exisisting pulmonary comorbidities showed no significant predictive value for occult pneumothorax. We suggest that any trauma patient presenting with subcutaneous emphesema, pulmonary contusion or rib fractures should be further evaluated with CT chest to exclude any underlying pneumothorax not visible on the regular chest radiograph. Figure 2 well demonstrates the predictability of occult pneumothorax. The presence of lung contusions and subcutaneous emphesema has prompted further evaluation with CT chest, which revealed a pneumothorax.

Bottom Line: Pneumothorax is a recognized cause of preventable death following chest wall trauma where a simple intervention can be life saving.However, in certain patients, especially those on mechanical ventilation (with subsequent increase of intrapleural air with positive pressure ventilation), missing the diagnosis of pneumothorax can be deleterious with fatal consequences.Because a negative AP chest radiograph can dangerously delay its recognition, we recommend that any trauma victim presenting to the emergency department with symptoms of respiratory distress should be screened with either thoracic ultrasonography or chest CT scan to avoid missing a pneumothorax.

View Article: PubMed Central - HTML - PubMed

Affiliation: Departement of Internal Medicine, Mercy Hospital and Medical Center, Chicago, Illinois, USA. hesham_omar2003@yahoo.com.

ABSTRACT
Pneumothorax is a recognized cause of preventable death following chest wall trauma where a simple intervention can be life saving. In cases of trauma patients where cervical spine immobilization is mandatory, supine AP chest radiograph is the most practical initial study. It is however not as sensitive as CT chest for early detection of a pneumothorax. "Occult" pneumothorax is an accepted definition of an existing but usually a clinically and radiologically silent disturbance that in most patients can be tolerated while other more urgent trauma needs are attended to. However, in certain patients, especially those on mechanical ventilation (with subsequent increase of intrapleural air with positive pressure ventilation), missing the diagnosis of pneumothorax can be deleterious with fatal consequences. This review will discuss the occult pneumothorax in the context of 3 radiological examples, which will further emphasize the entity. Because a negative AP chest radiograph can dangerously delay its recognition, we recommend that any trauma victim presenting to the emergency department with symptoms of respiratory distress should be screened with either thoracic ultrasonography or chest CT scan to avoid missing a pneumothorax.

No MeSH data available.


Related in: MedlinePlus