All posts by TheTraumaPro

When To Give Mannitol

Patients with severe head injury need all the help they can get. Mannitol is one tool that is time-tested and cheap. But how do you decide who gets it and when?

Mannitol is a powerful osmotic diuretic that pulls extracellular water from everywhere, including the brain. By reducing the size of the brain overall, it drops pressure inside the skull (ICP) somewhat.

Mannitol can be used anytime during the acute phase of trauma care for three indications in patients with head trauma:

  • Focal neurologic deficit. This is due to transtorial herniation, and may manifest clinically as unilateral pupil dilation or hemiparesis. It may also be seen on CT scan.
  • Progressive neurologic deterioration. This is typical of rising ICP and can be diagnosed when your previously talking patient becomes lethargic.
  • Clinical evidence of high ICP. This is the Cushing response (hypertension with bradycardia). Do not treat this hypertension with other meds, it is a brain protective mechanism!

The literature does not have any good studies that show effectiveness or survival benefit. However, most trauma professionals have seen the dramatic improvement in neurologic status that can occur after early administration.

Bottom line: Mannitol is cheap and it works! Consider it early if any of the three indications above are seen. And don’t forget to put a urinary catheter in immediately because the diuresis that it causes is impressive. And no studies thus far have been able to prove that hypertonic saline is any better or worse than mannitol.

Simple Tracheobronchial Injury

Injury to the airway has the potential to be a catastrophe, with rapid deterioration and death. Occasionally the injury is less dramatic with a slow air leak, but it can still present a diagnostic and management challenge. 

These lower airway injuries can occur after either blunt or penetrating trauma. The penetrating ones are relatively simple to diagnose because the wound tract is known and, if stable, a trip to CT demonstrates the problem area. 

Blunt lower airway injury is a bit trickier. These typically require a high energy mechanism, such as a motor vehicle crash. Up to half of these injuries are not diagnosed immediately. Typically, unexpected air on the chest xray is identified. Less commonly, subcutaneous emphysema appears and prompts more investigation.

Previously, the gold standard for diagnosis was bronchoscopy. CT has gotten so good that even smaller bronchial injuries can be identified, so CT is now the diagnostic study of choice. Management of injuries that do not threaten the airway consists of close observation. Smaller ones may heal on their own without complication. Larger injuries usually continue to leak and do not heal. If ventilation problems develop, either from persistent large pneumothorax or large amounts of air dissecting into the neck, intubation will be required. However, positive pressure may exacerbate the problem, so low pressure ventilation modalities must be used. A prompt trip to the OR will be required in such cases.

Bottom line: Simple (slow leak) tracheobronchial injuries are uncommon, but are seen after major blunt trauma and any kind of thoracic penetrating injury. The best way to diagnose the exact problem and location is thin cut CT of the chest. Injuries with minor clinical dysfunction can be admitted to the trauma service and observed. If the leak does not resolve, or causes breathing problems, a thoracic surgeon will very likely need to intervene to repair the problem.

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Trauma Patient Transport By Police, Not EMS

When I was at Penn 25 years ago, I was fascinated to see that police officers were allowed to transport penetrating trauma patients to the hospital. They had no medical training and no specific equipment. They basically tossed the patient into the back seat, drove as fast as possible to a trauma center, and dropped them off. Then they (hopefully) hosed down the inside of the squad car.

Granted, it was fast. But did it benefit the patient? The group now at Penn decided to look at this to see if there was some benefit (survival) to this practice. They retrospectively looked at 5 years of data in the mid-2000’s, thus comparing the results of police transport with reasonably state of the art EMS transport.

They found over 2100 penetrating injury transports during this time frame (!), and roughly a quarter of those (27%) were transported by police. About 71% were gunshots vs 29% stabs. They found the following interesting information:

  • The police transported more badly injured patients (ISS=14) than EMS (ISS=10)
  • About 21% of police transports died, compared to 15% for EMS
  • But when mortality was corrected for the higher ISS transported by police, it was equivalent for the two modes of transport

Although they did not show a survival benefit to this practice, there was certainly no harm done. And in busy urban environments, such a policy could offload some of the workload from busy EMS services.

Bottom line: Certainly this is not a perfect paper. But it does add more fuel to the “stay and play” vs “scoop and run” debate. It seems to lend credence to the concept that, in the field, less is better in penetrating trauma. What really saves these patients is definitive control of bleeding, which neither police nor paramedics can provide. Therefore, whoever gets the patient to the trauma center in the least time wins. And so does the patient.

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Reference: Injury-adjusted mortality of patients transported by police following penetrating trauma. Acad Emerg Med 18(1):32-37, 2011.

The Deep Sulcus Sign

Pneumothorax is frequently difficult to diagnose in the resuscitation room. Sometimes it is obvious, with a hypoxic patient and absent breath sounds. But not usually. Most of the time we rely on a chest xray to help make the diagnosis.

Unfortunately, the good old chest xray only shows a pneumothorax about 30-50% of the time. A big part of the problem is that our patients are usually supine to protect their spine. A small pneumothorax make float anteriorly in the supine position, and if it is not big enough to wrap around the lateral edge of the lung, it may remain invisible. So you need to look for gross and subtle signs on the image that will help make the diagnosis. The deep sulcus sign is one of the more subtle signs. 

Simply stated, the deep sulcus sign is a radiolucent (dark) lateral sulcus where the chest wall meets the diaphragm. The amount of lung in this area is less, so a small amount of air will tend to darken the area making it more prominent. Look at patient left in the left photo, and compare to their right side. It is much darker and appears to extend lower than usual. In more extreme cases, the amount of air just above the diaphragm may make it appear inverted (right photo).

Bottom line: If you see a deep sulcus sign on the chest xray image, strongly consider pneumothorax. If the patient begins to have hemodynamic problems, needle the chest and chase with a chest tube. If they remain stable, the patient will still require a chest tube. Chest xray always underestimates the true size of the pneumothorax. Place the usual size chest tube and manage per your usual protocol. And, as always, use your best sterile technique and definitively identify the proper side before placing the tube.

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Trauma Survival and Air vs Ground Transport

Wartime experience has shown that rapid transport from the battlefield scene of injury to definitive care dramatically improves survival. This has been translated into civilian trauma care by making helicopter transport to a trauma center more widely available. But this resource is still somewhat limited, and very expensive compared to ground EMS transport. Is this expense warranted, or in other words, does it improve survival?

Many have tried to answer this question. Several of these studies did show improved survival with air transport, but most had significant flaws that made their conclusions hard to interpret. The current issue of JAMA has published an article from MIEMSS and Johns Hopkins that tries to do it right.

The authors used the National Trauma Data Bank (1.8M records) and whittled it down to 223K by using pertinent exclusion criteria. About 25% were transported by air and 72% were taken to Level I centers (vs Level II). A sophisticated regression model was used to adjust for missing data and clustering by trauma centers.

They found that there is roughly a 1.5% survival advantage in taking patients to trauma centers by air. About 65 patients need to be transported to a Level I center, or 69 patients to a Level II center, to save a life. There are some issues with the statistics, primarily due to the nature of the NTDB data, but overall the paper is nicely done.

Bottom line: It looks like helicopter transport of seriously injured trauma patients conveys a very small survival advantage. However, this does not mean that everybody now needs to be flown in. This is not an ideal world, and not everybody is in an area that can provide such transport. Furthermore, in many areas ground EMS is still faster than air. And finally, air transport is much more expensive than the incremental survival increase may be worth. We will have to come to grips as a society to figure out what we can really afford.

Reference: Association between helicopter vs ground emergency medical services and survival for adults with major trauma. JAMA 307(15):1602-1610, April 18, 2012.