Several of you figured this one out! The patient was involved in a high speed car crash and was brought to the ED in respiratory distress. Decreased left sided breath sounds were noted. The following xray was obtained.
Opacity is noted in the left lung field, and a modest pneumothorax is seen on the right. Bilateral first ribs are fractured, and the left second through fourth ribs are also broken. The patient was intubated and bilateral chest tubes were inserted.
There was minimal blood from the left chest tube, and a small amount of air from the right. Note the extensive subcutaneous emphysema.
What should we do next? Are any other diagnostic tests indicated? Could the endotracheal tube placement be part of the problem?
Patients with chest trauma sustain hemothorax on occasion. The trauma professional usually picks this diagnosis up in the initial evaluation and makes a decision whether or not to drain it. The parameters for this decision are not very clear, even today. But what happens when there is residual hemothorax? Should we be more aggressive in getting it out?
All this boils down to an understanding of the natural history of retained hemothorax. This kind of information can help us decide whether to be more aggressive in our efforts to remove it. The results of a multicenter study looking at this issue was published recently. They focused on patients who had a chest tube placed for management of either hemo- or pneumothorax within 24 hours of admission. Patients who had suspected retained hemothorax after tube removal received a CT scan within 14 days. The usual outcomes were studied (length of stay, complications) as well as development of empyema (purulence, acidic pleural fluid, positive Gram stain or culture).
Some interesting results:
- 328 patients were enrolled across 20 centers. Not a lot, but one of the bigger studies to date.
- Empyema was diagnosed in 27% of patients
- Risk factors identified included rib fractures, ISS > 25, and performance of additional interventions for drainage
- Patients who developed empyema stayed in the ICU and the hospital longer
Bottom line: Retained hemothorax turns into a very serious problem in a quarter of trauma patients who have a chest tube inserted. The presence of residual blood after the chest tube is removed should prompt us to figure out if it’s solid clot or liquid blood (remember the old decubitus view chest xray? They still work!). If it’s liquid, consider drainage via thoracentesis or a smaller catheter. If it’s clot, it may require more invasive techniques to drain it (VATS). If you decide to send the patient home, have them watch out for fevers, chest pain, dyspnea and other symptoms and signs of a developing complication, and make sure they report it to you promptly.
Reference: Development of posttraumatic empyema in patients with retained hemothorax: Results of a prospective, observational AAST study. J Trauma 73(3):752-757, 2012.
Occult pneumothorax is a pleural air collection that is seen only on CT. It is not detected by standard chest xray either because of small size, location of the air, or position of the patient during xray (usually supine).
Approximately 15% of major trauma patients undergoing CT are diagnosed with an occult pneumothorax. The tough question is, what to do about it. Larger pneumothoraces are frequently treated with thoracostomy, but this procedure has its own list of associated complications. Patients undergoing positive pressure ventilation with a visible pneumothorax have an increased risk for progression to tension pneumothorax.
At our trauma center, we manage occult pneumothorax expectantly. If a pneumothorax is seen on the chest portion of a CT scan but not on the initial supine chest xray, a repeat conventional chest xray is scheduled for 6 hours later. Ideally, this xray is taken using the best technique (upright, PA, xray source 6ft from patient). However, this is not always practical for severely injured patients.
If the pneumothorax remains occult on the followup xray, no further monitoring is performed. If the pneumothorax becomes visible, repeat chest xrays are obtained every 6 hours until it is stable or it becomes large enough to warrant insertion of a chest tube.
How large is large enough for a chest tube? That’s the subject for another day.