Chest x-rays often miss pneumothoraces in the trauma room. These are occult pneumothoraces. A study using agreement by two fellowship trained radiologists as the gold standard for CXR interpretation showed that 80% of these were truly occult, ie. not detectable by the radiologists from CXR and only demonstrable on CT. Of those seven cases that could or should have been identified by emergency physicians (ie. ‘missed’ pneumothoraces) subcutaneous emphysema (5), pleural line (3), and deep sulcus sign (2) were detected by the radiologist reviewers.
This serves both as a reminder of the signs to look for on CXR for pneumothorax, and of the inadequacy of plain radiography in trauma patients. The authors advise in their discussion that ‘Thoracic ultrasonography may be the ideal diagnostic modality as it has a high sensitivity for the detection of PTX and it may be performed quickly at the bedside while maintaining spinal precautions’.
If you don’t know how to detect a pneumothorax with ultrasound yet, have a look here.
Occult Pneumothoraces Truly Occult or Simply Missed: Redux
J Trauma. 2010 Dec;69(6):1335-7
A case report describes the echo findings of a patient with a traumatic left sided pneumothorax. Although the subcostal view was unremarkable, upon imaging the parasternal region, the sonographer noted a flickering phenomenon where the heart was clearly visualized in late diastole, but would disappear in mid- systole only to reappear in late diastole during the next cardiac cycle. This ‘‘heart point’’ sign occurs because as the heart fills with blood in diastole, it enlarges and displaces the air from the precardiac space, allowing the heart to transiently contact the chest wall and be visualized with US. As the heart contracts during systole, the pneumothorax fills the space between the heart and the anterior chest wall, preventing the transmission of US and causing the heart to momentarily disappear from view.
The Heart Point Sign: Description of a New Ultrasound Finding Suggesting Pneumothorax
Academic Emergency Medicine 2010;17(11):e149–e150
The Britsh Thoracic Society has published its 2010 guidelines on the management of spontaneous pneumothorax. These are one of number of guidelines for the management of pleural disease.
Management of spontaneous pneumothorax: British Thoracic Society pleural disease guideline 2010
Thorax 2010;65(Suppl 2):ii18-ii31
All pleural disease guidelines
The UK National Health Service’s National Patient Safety Agency published a report entitled ‘Risks of chest drain insertion’, reporting 12 deaths and 15 cases of serious harm related to chest drain insertion over a three year period. They issue the following recommendations under the title ‘For IMMEDIATE ACTION by the NHS and independent sector – Deadline for ACTION COMPLETE is 17 November 2008’:
Clinical governance leads in local organisations should audit current practice and develop local policies to ensure:
- Chest drains are only inserted by staff with relevant competencies and adequate supervision
- Ultrasound guidance is strongly advised when inserting a drain for fluid
- Clinical guidelines are followed and staff made aware of the risks
- Identify a lead for training of all staff involved in chest drain insertion
- Written evidence of consent is obtained from patients before the procedure, wherever possible
- Local incident data relating to chest drains is reviewed and staff encouraged to report further incidents
Chest drains: risks associated with the insertion of chest drains
National Patient Safety Agency
Radiographs of 49 spontaneous pneumothoraces were studied, showing that in the expiratory films, pneumothoraces were on average 9% larger. When applying British Thoracic Society or American College of Chest Physicians guidelines, this difference would have led to a different management strategy.
What is the difference in size of spontaneous pneumothorax between inspiratory and expiratory x-rays?
Emerg Med J. 2009 Dec;26(12):861-3
In both adults and children, abdominal distension (which may be massive in children) may be a sign of tension pneumothorax.
Crisis management during anaesthesia: pneumothorax
Qual Saf Health Care. 2005 June; 14(3): e18
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