Penetrating Trauma: What We Miss and How We Can Improve
Authors: Elliott Chinn, DO (EM Resident Physician at Jacobi Medical Center) and Steve McGuire, DO (EM Chief Resident at Jacobi Medical Center) // Edited by: Alex Koyfman, MD (@EMHighAK, EM Attending Physician, UTSW / Parkland Memorial Hospital) and Brit Long, MD (@long_brit, EM staff physician at SAUSHEC, USAF)
During your next shift you hear “Level 1 Trauma in 5 minutes”. The patient arrives. He is a 28 year-old male, stabbed in the chest, with the following vitals: T 98.6 HR 95 BP 105/70 RR 20 PO2 98% RA. He’s talking, you see a 2 cm stab wound to the left subcostal region, his breath sounds are even bilaterally, and his repeat blood pressure is 115/80. He’s moving all of his extremities so you log roll him and see no other injuries. A supine chest x-ray is done which is negative, and a quick FAST is unrevealing. You step away for a brief moment to put in orders when you’re notified that the patient is lethargic and his heart rate jumped to 160. You put on your stethoscope, suspecting to hear decreased breath sounds and when you do, you place a 14g angiocath into his chest and “wwhheeww”, you and your patient release some tension.
What happened? What did you miss and why?
Your next patient is a 50 year-old male with abdominal pain. He doesn’t look so great and doesn’t offer much for medical problems. You notice an old, vertical scar on his chest. “Oh yeah doc, I was stabbed a long time ago”. His labs come back, and he has an elevated WBC and lactate. Hours later, he is in the OR for a strangulated hernia that was in his thorax, a complication of an undiagnosed diaphragmatic injury.
What happened? What did you and the previous doctor miss and why?
Hours later you see another stabbing victim, only this time the wound is just underneath his umbilicus. The puncture doesn’t look that deep, and the patient’s vital signs are stable. While he is complaining of pain, his abdomen doesn’t feel like a surgical abdomen. A CT scan is ordered and when it comes back it is negative. You scratch your head and think to yourself, “Can I send this patient home?”
What are you worried about missing and what can be done to reassure you?
Your next patient is here for left-sided back pain. He was just discharged four days ago after being shot in the stomach. He is febrile, tachycardic, and has no other medical or surgical history aside from his previous trauma. Hours later, your CT scan shows a perinephric abscess, and he’s admitted for IV antibiotics.
What happened? What did the surgeons miss and why?
Our role as ED physicians is to stabilize the patient while determining their disposition. Inevitably, we are going to miss things, as it isn’t our job to diagnose every injury. This post will discuss injuries we can miss related to penetrating trauma in the acute and post-discharge setting.
Case #1: Tension Pneumothorax
Tension pneumothorax (TPTX) is one of the deadliest, cannot miss diagnoses we are responsible for. We are trained to think of pneumothorax when we see respiratory distress, chest pain, and decreased lung sounds, and when paired with hypotension, tachycardia, and dropping PO2, we should reflexively think of tension pneumothorax. Primarily a clinical diagnosis, it should not be diagnosed radiographically.
In the real world, diagnosing a tension pneumothorax, let alone before x-ray, is not as easy as we are led to believe. A review of 18 case reports in awake, non-ventilated patients showed that “classic” signs such as low Sp02, tracheal deviation, and hypotension are found in less than 25% of cases (1). Furthermore, a case series of 115 consecutive tension pneumothoraces in South Africa showed that 25% were missed on initial assessment, with 40% of those patients dying (2). Even more concerning, that series took place in a region that gets 30 cases of tension pneumothorax a year, which is more than most U.S. hospitals see.
That study did not look into why the diagnosis was missed. Perhaps they stopped their diagnosis at pneumothorax because they didn’t see textbook signs that as it turns out, may not be so textbook. So, what can we do to make sure we do not miss this diagnosis?
First, always have a high index of suspicion for tension pneumothorax, taking into account many of the classic signs we are taught to look for are often not present. Second, confirm your clinical exclusion of the diagnosis with ultrasound, as it has been shown to have a higher sensitivity than upright or supine chest radiography and has a negative predictive value approaching 100% (3). Finally, avoid supine CXR at all cost. A recent article showed it has a significantly lower sensitivity than upright, only catching 21% patients with a pneumothorax (4).
Case #2: Diaphragmatic Injury
Missing a diaphragmatic injury will not immediately harm your patient; however, months to decades later it can have devastating consequences if not recognized.
The range of diaphragmatic injuries missed on CT scan ranges anywhere from 12-63%, but more disturbingly, the mortality rate for subsequent complications can be as high as 60% (5,6). One study found complications like herniated stomach, large gut, spleen, liver, and gangrenous gut if there is a delay in presentation, even “fecopneumothorax” if that herniated organ is mistaken for a pleural effusion on chest x-ray and a chest tube is placed (6).
The gold standard for diagnosing diaphragmatic injury is surgery, but in an era of increased nonsurgical management, some of these injures are missed. CT scan lacks the sensitivity and specificity of surgery, so we cannot rule it out with imaging alone. There is a wide range of sensitivity for picking it up on CT. One review article cited a range of 61-87%, while showing that sensitivity is worse when the injury is on the right due to the homogeneity between the liver and diaphragm (5). In one small but well conducted study, patients with penetrating trauma to the left thoracoabdominal area who went to the OR 48 hours after CT scan showed a sensitivity of 82%, with a negative predictive value of 93%.
What can we do as ED physicians to improve? First, be specific in your indication for why you are getting a CT scan. Traumas can be chaotic environments, and we might overlook the importance of identifying entry points and mechanism when we order imaging which can be valuable clues to radiologists. One might be so bold as to say “rule out diaphragmatic injury” to further clue them in, as there are several direct and indirect signs of diaphragmatic injury on CT, some of which are more common in penetrating trauma.
While a missed diaphragmatic injury isn’t usually at the top of our differential for most chief complaints, it should at least be considered in a patient with a history of thoracoabdominal trauma. It is definitely one with serious morbidity/mortality if left undiagnosed and unfortunately, could present days to years down the line and seem completely unrelated to their past medical history.
Case #3: Hollow Viscus Injury
In penetrating abdominal trauma there are hard signs for going to the OR: hemodynamic instability, evisceration, or peritonitis. What should be done when there are no hard signs has been a matter of debate since the 1960s. In 2009 the Western Trauma Association put out a guideline which was again tested in 2011 that advocates for local wound exploration in stable patients who have anterior abdominal stab wounds (8). Their goal was to bring everyone to the OR who needed to be there while minimizing unnecessary surgery, procedures, and imaging.
Their guidelines were simple: if the patient is stable, perform local wound exploration and if it is positive, admit for serial clinical assessments with a CBC every 8 hours. If the patient deteriorates clinically, they go to the OR. If they were stable for a day then they could be discharged.
If wound exploration was negative then the patient could be discharged, without relying on a negative CT scan or labs.
It should be noted that they had a strict protocol for wound exploration, which required anesthetizing the wound and probing the entire depth. If posterior fascia or peritoneum were violated, it was considered positive.
How did it all pan out? Patients in the protocol group were significantly less likely to get an unnecessary laparotomy, and they were not at increased risk for complications. They were just as likely to be discharged from the ED, and none of them had a CT scan. Patients whose surgeons did not follow the protocol and used imaging or labs to guide their decision had more unnecessary procedures, with increased length of stay in the hospital and more complications. Most patients who went to the OR after being admitted for serial exams went within four hours, with the last patient going at 15 hours, and their rate of complications was not any higher than those who went straight to the OR.
In the past, local wound exploration has gotten a bad reputation. If you are still not a fan of it, you can still skip the reflex to go straight to the CT scanner as long as your patient is stable and your surgical service can observe them. One study found that no injuries were missed when a patient was observed for 24 hours, and those who waited to go to the OR did not have a higher rate of complications than those who went immediately (9). This is important because some clinicians think they can discharge patients home if their CT scans are normal when in fact it could be a false negative. Additionally, there are cases of false positives on CT that lead to wasteful trips to the OR (8).
The point here has more to do with empowering us to not instinctively take our patients to the CT scan or push our surgeons, unnecessarily, to take our patients to the OR. This is an opportunity to not miss an injury by not doing something, which harms our patients in a way we cannot yet quantify.
To summarize, hollow viscous injury is a diagnosis we can miss if we don’t watch a patient for long enough, and research shows that 24 hours is the longest it will take your patient to deteriorate (9). Local wound exploration could be a tool to let us exclude the diagnosis without having to admit every single patient with penetrating abdominal trauma. We should allow our clinical exam to guide our management, not imaging or lab values.
Case #4: Ureteral Injuries
Surrounded by some significant real estate, the ureters are very well protected. If those organs are involved, a ureteral injury may be missed, so it must be on the differential in any patient who presents shortly after being discharged from a hospitalization related to penetrating injuries.
A well conducted review of ureteral injuries showed they mostly affect men who were victims of penetrating trauma, involved the proximal ureter (defined as from the ureteropelvic junction down to the sacroiliac joint), and actually lacked hematuria, regarded as some to be the hallmark of ureteral injury (10). 90% of the time there will be an associated injury, almost always (96%) bowel injuries.
As with other rare injuries, they require a high index of suspicion. Close to 38% of ureteral injuries can cause complications such as retroperitoneal abscess, infected urinoma, and fistula, but in rare circumstances they can lead to renal failure and sepsis. CT scan by itself isn’t the best way to diagnose it, and even when patients go to the OR it is missed about 40% of the time.
So what can we do to avoid this? In any penetrating trauma patient with hematuria, consider getting GU involved, especially if your patient is going to have to sit in your department . Specially timed CT scans (“delayed excretory phase images”) might be necessary to make the diagnosis in the acute setting. Understand that the absence of hematuria is actually more common in ureteral injuries, so its absence cannot exclude it. If the patient was recently discharged after sustaining penetrating trauma, have a high index of suspicion for this injury, as it could have been missed on initial presentation.
As ED doctors we play a critical role in trauma. Many of our patients who suffer injuries from penetrating trauma get admitted, ultimately receiving a “trauma tertiary survey” prior to discharge. This is a critical step in their care, and research shows that it transforms many “missed injures” into “delays in diagnosis”, meaning they are caught before they cause a problem (11).
In the acute setting the most important thing we can miss is a tension pneumothorax. Thankfully, ultrasound is accessible and with ultrasound education being integral in most residency training programs, it is only a matter of time until most ED doctors can rule it out nearly 100% of the time.
In the patient with a history of penetrating trauma we need to be aware of two injures that could have been missed: diaphragmatic tears and ureteral injuries. While CT scans can miss asymptomatic tears, they are quite good at diagnosing organs that have herniated through the diaphragm so if you are suspicious of it, order that CT scan. In any patient with abdominal or flank pain, fever, or urinary symptoms who has a history of penetrating trauma, consider ureteral injuries because you may need special imaging to diagnose it.
Finally, despite advances in imaging, hollow viscus injuries continue to be a diagnosis that can be missed in the absence of observation and serial abdominal exams. The utility of local wound exploration will likely be debated for some time, but there is growing evidence that it can be used to exclude hollow viscus injury if done appropriately while saving patients from unnecessary radiation and trips to the OR.
References / Further Reading:
- Leigh-Smith SS. Tension pneumothorax – time for a re-think? Emergency medicine journal: EMJ. 2005-01;22:8-16.
- Kong VV. Traumatic tension pneumothorax: experience from 115 consecutive patients in a trauma service in South Africa. European journal of trauma and emergency surgery (Munich: 2007). 2016-02;42:55-59.
- Nandipati KK. Extended focused assessment with sonography for trauma (EFAST) in the diagnosis of pneumothorax: experience at a community based level I trauma center. Injury. 2011-05;42:511-514.
- Ball CC. Occult pneumothoraces in patients with penetrating trauma: Does mechanism matter? Canadian journal of surgery. 2010-08;53:251-255.
- Panda AA. Traumatic diaphragmatic injury: a review of CT signs and the difference between blunt and penetrating injury. Diagnostic and interventional radiology (Ankara, Turkey). 2014-03;20:121-128.
- Ganie FF. Delayed presentation of traumatic diaphragmatic hernia: a diagnosis of suspicion with increased morbidity and mortality. Trauma monthly. 2013;18:12-16.
- Yucel MM. Evaluation of diaphragm in penetrating left thoracoabdominal stab injuries: The role of multislice computed tomography. Injury. 2015-09;46:1734-1737.
- Biffl WW. Validating the Western Trauma Association algorithm for managing patients with anterior abdominal stab wounds: a Western Trauma Association multicenter trial. The journal of trauma. 2011-12;71:1494-1502.
- Inaba KK. Selective nonoperative management of torso gunshot wounds: when is it safe to discharge? The journal of trauma. 2010-06;68:1301-1304.
- Pereira BB. A review of ureteral injuries after external trauma. Scandinavian journal of trauma, resuscitation and emergency medicine. 2010;18:6.
- Pfeifer R, Pape H-C. Missed injuries in trauma patients: A literature review. Patient Safety in Surgery. 2008;2:20. doi:10.1186/1754-9493-2-20.