Trauma Surgery

Sow Lava, Harvest Igneous Rock

To change with change is the changeless state.

Bruce Lee

Hello everyone!

Today we are going to dig deep into one of the most treacherous chapters of thoracic trauma… The retained hemothorax…

Well… Let’s not waste time and dive in…

On-call, as usual… Called by the ER doctor, as usual…

But today there’s something new waiting for you in one of the cubicles…

A 21-year-old man, intoxicated, who tried to approach the wrong girl… End of the story: a nice single stab between the 5th and the 6th rib on the right hemithorax.

The patient is not particularly in pain, and his breathing is fine. However, nothing can stop you from doing your usual and complete primary and secondary survey…

At the end of your evaluation, the only thing that is not normal is a small right pneumo-hemothorax seen on the chest x-ray (CXR).

Now, how to manage this?


Let’s start from the beginning… Logically, if you have to manage a retained hemothorax, you first need to have a “normal” hemothorax…

A hemothorax is blood accumulation in the pleural cavity, generally due to chest trauma, either blunt or penetrating, disrupting lung parenchyma and/or surrounding vessels.

The hemothorax can be considered massive if there is a loss of blood of more than 1500 mL in a brief period leading to lung collapse and hypoxia. This eventuality is the consequence of a major mediastinal vascular injury, a massive lung parenchyma laceration, and/or an intercostal vessel injury. When you are facing a massive hemothorax, the only option you have is the OR… Remember that if the patient’s physiological state does not allow him/her to be moved, you need to perform an emergency room thoracotomy. More debated is the indication to proceed to the OR in case of an intercostal tube draining more than 200 mL/h of blood for more than 2-4 hours.

Ok… Now we know what a hemothorax is…

A retained hemothorax (RH), on the other hand, does not have a well-defined definition… Some authors define it as “a residual pleural blood >500 mL in volume (500 mL because it is the limit to identify it on CXR)”, others as “blood occupying greater than one-third of the hemithorax”, or as “any residual blood that cannot be drained after 72 hours”. One of the consequences of this lack of clear definition is that its incidence is highly variable, ranging from 4% to 35%.

Broadly speaking, we can define a RH as any residual pleural collection beyond 48-72 hours from the initial intercostal drain (ICD) insertion.

Remember that an ICD is successful (and the only intervention needed) for a traumatic hemothorax in up to 85% of patients.

Now, you may ask: why do we care so much about retained hemothoraces? Can’t we just leave them be? Or leave the drain in for some more days?

Well, the problem is that both alternatives may lead to acute and/or chronic complications:

  • Acute
    • Empyema (27%) – it is a purulent pleural collection, characterized by a low pH (<7.2), signs of infection, and/or proven bacterial invasion on Gram stain or culture;
    • Pneumonia (19.5%)
  • Chronic
    • Fibrothorax – it is the consequence of the development of dense fibrous membranes inside the pleural cavity, reducing the normal movements of the lungs;
    • Entrapped lung – it is the inability of the lung to fully expand inside the pleural cavity because of a fibrinous restrictive pleural layer that prevents normal visceral and parietal pleural apposition.

These complications, as such, may increase patients’ morbidity, length of stay, and the overall costs to manage these patients.

Not so fun, right?!… Then: how to avoid their development?

The fundamental rule is “prevention is better than cure”… Starting from it, we can divide the general management into two steps:

  1. Preventing RH
    1. Identify patients at risk for RH
    2. Treat the hemothorax properly
  2. Preventing RH’s complications (or treating RH)
    1. “Conservative” treatments (e.g. antibiotics, a second tube, suction…)
    2. Invasive treatments (fibrinolytics, video-assisted thoracoscopy surgery (VATS), thoracotomy)

Preventing the Retained Hemothorax

So then… Let’s try to identify the patients at higher risk of developing a RH.

Firstly, each patient with a chest tube must start physiotherapy as soon as possible! Even just blowing into a glove is enough.

Scott et al. Reported that patients presenting with an Injury Severity Score >25, having a bilateral hemothorax, and intubated on admission, are at higher risk of developing a RH. Basically, those patients who sustained a more severe trauma to the chest have more chances of developing a RH… Not so surprising…

Now, what to do with patients who have a hemothorax on arrival? Do we have to drain all hemothoraces? How to manage them properly?

Well… If the hemothorax is “big”, no discussions are needed… We must put an ICD in… But, if we have to deal with a “so-called” occult hemothorax, things get a little bit more tricky.

First of all, we have to define the occult hemothorax…

Eisenberger et al. correlated the thickness of the pleural fluid at CT scan with the volume of fluid inside the chest, reporting the following association:

Fluid ThicknessFluid Volume
<1.5 cm<260 mL
1.5-4 cm260-1000 mL
>4 cm>1000 mL

Using the lower cut-off, Bilello et al. showed how only 15% of patients with a hemothorax smaller than 1.5 cm required an ICD compared to 66% of patients with a larger pleural collection. This result was confirmed, and no difference in empyema rate was recorded between patients drained and not drained, and between those who had an ICD and those who failed the non-operative management (i.e. needing a “delayed” ICD). Moreover, predicting factors of conservative management failure were identified as well:

  • Elderly;
  • Fewer ventilation-free days;
  • Hemothorax >300 mL;
  • Pneumohemothorax.

Even if you have to put an ICD in, you are allowed to be conservative, using smaller tubes (i.e. 28-32 French) instead of bigger ones (i.e. 36-40 French), without increasing the complication rate or the need for more advanced treatments (e.g. additional chest tube, thrombolysis, VATS…). Additionally, in the last years, more extreme measures were tried to reduce the invasiveness of chest tubes, comparing “regular size” drains to 14 French pigtail catheters. The rationale behind this is: if the blood is fluid you can drain it in the same way with both regular ICD and pigtail, if the blood is clotted you cannot drain it either with a “big” tube or a “small” one. In fact, this hypothesis was confirmed by Bauman et al., who showed how both draining methods had the same complication and failure rate, the same length of stay, and the same mortality. It should be said that not all surgeons agree with the results of this study, and most of them still use “small size” regular ICDs (e.g. 24-26 French) instead of pigtails.

Another issue to address is whether antibiotics are useful after the ICD insertion to prevent the development of infective complications. Unfortunately, to date, there are no clear indications by guidelines on the use of “prophylactic” antibiotics. However, a “not-so-recent” systematic review and meta-analysis by Bosman et al. demonstrated how antibiotic prophylaxis is useful to prevent infections in penetrating traumatic thoracic injuries, but not in blunt ones. This is also intuitable: a penetrating traumatic injury is not sterile, whereas a blunt one has no contamination from the outside. Based on this, some centers prefer to use antimicrobial therapy against Gram + bacteria, the most involved germs.

Thoracic irrigation is another possible method examined to reduce the incidence of RH, and it seems to be effective in that. The reported protocol is to irrigate the chest with NaCl 0.9% 1000 mL along with suctioning, then leave the ICD with -20 mmHg suction on. On the other hand, suction alone was shown not to improve the outcomes. There is not enough evidence to support or refuse these methods, though.

Managing the Retained Hemothorax

Good job guys… We have tried our best to avoid a RH, and now, after 48 hours from the index trauma, we want to see if we succeed… But, what do we need to determine if there is a RH or not? CXR or chest CT scan?

Literature is quite straightforward on this: CXR interpretation is wrong in half of the cases, and CT scan changes the management of one-third of patients. Also, as we have seen before, the CT scan allows to esteem quite well the amount of blood contained in the pleural cavity using the following formula:

V = d2 x L

V – the volume of blood inside the pleural cavity; d – greatest depth of the effusion on a single CT image; L – greatest length of the effusion on a single CT image.

How pulmonary consolidations may mimic a RH at CXR.

Image by Velmahos et al.

The diagnosis of RH at CT scan includes the following criteria:

  • Blood present up to 72 hours after the initial intervention or the index trauma;
  • Heterogeneous fluid collection;
  • 35-70 Hounsfield (remember that higher HU means more dense material);
  • Evidence of pleural thickening;
  • Blood volume greater than 300-500 mL or occupying at least one-third of the hemithorax.

Well, we have done everything possible, but the patient had developed a RH. Now we need to properly treat it to prevent the onset of the infective complications.

The identification of patients at higher risk of developing an empyema is useful to determine in which cases adopt a more aggressive approach. In this setting, independent predictive factors were identified as:

  • Rib fractures;
  • ISS ≥25;
  • Additional intervention (e.g. second ICD, VATS, thoracotomy).

Among these three factors, the first one may be addressed directly to reduce the risk of empyema. In fact, surgical stabilization of rib fractures may improve the outcomes, thus reducing the incidence of RH and, consequently, empyema. We will not linger on the rib fractures surgical management issue this time; so, take it as it is…

The first option to treat a RH is to insert a second tube to help the first one drain the remaining blood from the pleural cavity. However, comparing the second ICD to VATS, the “more conservative” method has poorer outcomes in terms of duration of tube drainage, hospital stay, and costs. However, the authors exploring this possibility suggest reserving this option for patients not manageable surgically.

Another “conservative” treatment option is fibrinolytic therapy:

  • 250k IU streptokinase or 100k IU urokinase in 100 mL of NaCl 0.9%, or tPA (Alteplase®) 5-10 mg in 50 mL of NaCl 0.9% through the ICD;
  • Wash the tube with a further 50 mL of NaCl 0.9%;
  • Close the tube and leave it to dwell for 3-4 hours;
  • Repeat the procedure once or twice daily for 3 days, then ask for a follow-up CXR to evaluate the response.

Fibrinolytics are not drugs to be used lightly. In fact, not all patients can receive them. Absolute contraindications are active bleeding, coagulopathy, intracranial injury, active cancer, and hypertension. Besides this, fibrinolytic therapy is beneficial in avoiding surgery in more than 80% of patients with RH (83% treated with tPA, 87% treated with non-tPA (i.e. streptokinase or urokinase). Nevertheless, comparing the use of fibrinolytics to VATS, it appears clear that the surgical option carries advantages in terms of shorter hospital stay and the need for further treatments. No difference in RH resolution rate and morbidity was found between the two treatments, though.

Analyzing what we said till now on the RH treatment options, it jumps to the eye that VATS is quite the rule changer. However, it should be performed as soon as possible to yield the maximum benefit. Waiting for more than 2-3 days from the diagnosis of RH progressively increases the infection rate, the need for further treatments, the hospital stay, and the mortality.

The last resort in the management of RH is thoracotomy, and it usually becomes necessary in case of synchronous diaphragmatic injury, RH >900 mL in volume, and/or no antibiotics administered during ICD insertion. From one point of view, it indeed has the highest success as a definitive procedure with 79% of patients needing no additional therapy. On the other hand, thoracotomy with decortication (i.e. excision of the thick fibrinous peel from the pleural surface, thereby permitting the expansion of the underlying lung parenchyma) for empyema and pleural effusion carries a high risk of discharge to transitional care (26.3%), complications (39.3%), and death (3.1%).

In conclusion, as we stated before, the best approach is to avoid the onset of RH and, if it develops, to treat it properly.

IPFT – Intrapleural fibrinolytic therapy.
Good operative candidate – good hemodynamics, no active bleeding, no severe comorbidities, good cardiopulmonary function, able to tolerate one-lung ventilation.
Surgical evacuation – VATS should be always preferred over thoracotomy, if possible.

Flowchart by Bozzay et al.

The main goal of this protocol is to reduce the number of needless procedures and, consequently, the related morbidity and mortality.

Concluding, we can state that:

  • Traumatic RH is still a major concern, mainly because it is not clear how to prevent it;
  • Chest CT scan (not CXR) is the gold standard for the diagnosis of RH;
  • In the case of a small (<300 mL) RH, it is possible to just observe it;
  • Fibrinolytics are effective and should be considered in poor surgical candidates;
  • VATS should be the preferred surgical option over thoracotomy in large (>300 mL) RH.

And, with these last pearls, we have finished our digression on RH.

We really hope you have enjoyed the journey!

See you soon…

In the meanwhile, stay tuned…


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How to Cite This Post

Bellio G, Marrano E. Sow Lava, Harvest Igneous Rock. Surgical Pizza. Published on July 23, 2022. Accessed on September 24, 2022. Available at [].

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