Welcome back to another episode of thecase.report! After a small episode hiatus, we’re back talking all things Trauma. Following on from our South Africa Special II last month, we’re back in Ireland in a rural ED where Eoghan, the only Reg on in ED this evening gets a pre-alert about a female involved in a road traffic collision with prolonged extraction.

From the seatbelt sign and it’s association with intra-abdominal pathology to the “Hateful Eight” and the electrolytes in red cells, Callum, Eoghan and our AITR Dr Sean Croughan are doing a deep dive of managing the unstable trauma patient.

As always, don’t forget to follow us on socials on instagram, twitter and facebook to keep updated with all things TCR. Right then, let’s get to it!

The Pre-hospital alert

Ah, the sweet, sweet sound of the pre-hospital alert phone.

Innate Response: Shiver. Glup. Take a deep breath. Focus. Prepare.

The Location: A rural Irish ED

The Time: Midnight

The staffing: You are the only Reg working the night shift. You have a CSTEM SHO and 2 nurses available to help out.

The Case: A female casualty of an RTC is en route with paramedics. Deformed left ankle, shortening of the right leg and thigh swelling reported. GCS 15.

The Vitals: HR 120 | BP 110/60 | Temp 35C | SpO2 99% RA | RR 20

The ETA: 20 minutes

As always, preparation is key.

The zero-point survey

Crucially, in this case, there is no formal trauma team in the hospital. There is an on-call, on-site surgical and orthopaedic SHO, with some on-call off-site staff. While at risk of sounding like a broken record, we direct you once more to the title of this paragraph.

We had a great discussion about the zero-point survey and the evidence behind it back in season 2, check out our S2E6 - Burns episode to learn all about how to prepare yourself, your staff and your ED and equipment (while it is covered in the context of prepping for intubation in a burns patient, the concept remains the same).

Preparation is always scenario dependant, and in the context of having no formal trauma team, there’s going to be a lot of phone calls. Specifically, this will involve contacting the ortho/surgical SHO and asking them to let their seniors know there is an incoming trauma, as well as putting radiology, ICU/critical care and haematology/transfusion on standby.

Our RTC management infographic covers some of the essentials in preparing and managing this complex patient cohort, you can download it here.

Identifying “Red Flags” early

Eoghan is quick on the mark at the in-person handover, and is immediately concerned about several elements of the patient’s journey thus far:

Significant damage to the passenger compartment with prolonged extraction
High energy mechanism
Abnormal vitals
History of transposition of the great vessels

Trauma assessment

Summary of findings on cABCDE assessment of this patient.
Note for medical students: *Listen along with the episode and note Eoghan’s interventions at each level of assessment* *before* *moving on to the next part.*
IV access

“I’ll place 2 large bore IVs bilaterally into this peripherally and centrally shut down patient as per the ATLS guidelines, and it’s as easy as that”

— No one, ever

Crucial, but tricky, IV access in trauma is an absolute must early on, and can avoid difficult resuscitation efforts if the patient suddenly deteriorates. If the paramedics were unable to get access pre-hospital, then be prepared for a tricky cannulation. US guided PIVC is an option, but can take time and be cumbersome.

Our AITR talks a little about this later on in the episode - in an obtunded patient with difficult access, he would consider moving from PIVC insertion to intra osseous (IO) if attempts have not been successful after around 2 minutes. A few notes on IOs:

Location

IOs should be placed above the level of injury in trauma (as placing them below could result in complete extravasation of whatever is infused), thus if there is a pelvic fracture, a humeral head IO is probably the best option. Tibial is colloquially the easiest to place, but this may not be an option. However, while humeral head IOs can have an up to 2x flow rate, they are also the site of most variability, thus it is essential to test the flow rate of your line once inserted - this may prove critical later in the patient’s management

It Pays to be kind

IOs may be placed in an awake patient, but as you’ll know if you’ve seen any of the Youtube videos of military soliders inserting them on each other, it’s the flush that really hurts. Dr Croughan suggests using a little lidocaine in conscious, alert patients and leaving for 30 seconds to numb the pain a little.

Managing haemorrhage

Check out our infographics for advice on “Turning off the Tap” the “Hateful eight” of exsanguinating haemorrhage, identifying the source(s) and maintaining homeostasis.

VBG values

Note: This is not a real VBG and image is for illustrative purposes only. Ranges my differ in real life.

VBG in haemorrhagic shock

Hb

The drop in Hb seen in the setting of haemorrhage is secondary to an adaptive mechanism of the body to increase volume but does not happen immediately. Hb is a measure of concentration. If someone is losing blood rapidly, while the volume of blood in the system changes, the concentration of Hb initially stays the same. Thus, one should not be falsely reassured by a normal Hb in haemorrhage in the acute setting.

As our AITR points out, there is good evidence that base excess actually out performs the traditional ATLS rubric in the assessment of severity of shock and overall injury severity. A base excess which is becoming progressively more negative should send alarm bells ringing in your head.

Ionised calcium

There is a growing evidence base that low calcium is associated with more severe bleeding and shock states as well as with the development of acute coagulability of trauma. Correcting hypocalcaemia has become a staple of good quality trauma care, so much so, that the US military guidelines now advise treating trauma patients with 1g of CaCl empirically, followed by titrated boluses based on the amount of units of blood transfused.

Potassium

See our AITR section below where Dr Sean Croughan discusses the composition of red cells and the potential for post massive transfusion cardioplegia syndrome, in the context of hyperkalaemia and hypocalcaemia.

I promise this isn’t for a headache…

Patient stabilised and ready for CT

With the displaced limb back where it should be, the patient warmed, the vitals stably unstable and the team happy that nothing has been missed, the patient is ready for CT. The zero point survey carried out at the start means the radiologist is already in house, and ready to scan. The patient is returned to the department, and while your team are reassessing the patient, you get a call from the radiologist with a brief verbal on the CT trauma series:

CT no acute intracranial findings. No C-spine fracture. Anterior compression fracture @ T10

No PTX/effusion. Early signs bilateral pulmonary contusion

Small amount free fluid in abdomen no active extravasation of liver/spleen injury seen. Some subtle oedema around one loop small bowel

Plain films showed displaced midshaft fracture right and trimalleolar fracture of left ankle.

While the CT findings suggest there is no need for any immediate life saving interventions, there are several concerning signs which are going to need to be monitored closely over the next number of hours and days. Pulmonary contusions may worsen so it’s important to have supplemental oxygen ready, as well as giving ICU a heads up if that hasn’t been done already. We’ll get to the bowel oedema and free fluid in a bit.

Beyond the ED

It’s true, such a place exists.

We learn at the end of the case that the patient is transferred to another hospital the following day and underwent a successful fixation of the ankle and femur on the day of transfer. However In the days after, the patient developed sepsis secondary to peritonitis and required a bowel resection and anastomosis. They had a prolonged critical care admission with multiple radiologically guided drains and two more trips to theatre for management of intra-abdominal complications before she was able to be transferred back to local hospital for extensive rehab.

While our role in the patient’s care may end at the time of transfer to the medical or surgical team, there were some potentially worrying signs for the patient’s future course seen on exam and CT. It’s easy to overlook the importance of a thorough handover to the specialist team, however doing so enables them to watch out for potential health concerns in future. Now, back to that bowel oedema…

Bowel injury in Trauma

Bowel is the third most commonly injured abdominal organ in blunt trauma, with major bowel or mesenteric injuries found in 5–17% of laparotomies for blunt trauma. The incidence of hollow viscus injury is thought to be increasing secondary to higher numbers of high speed collisions with seatbelt usage.

Why awful statistics matter

One study published in the European Journal of Radiology found that clinical exam alone had a 16% sensitivity for bowel and mesenteric injuries in blunt trauma. Another study concluded that overall contrast enhanced CT only 10–15% sensitive for bowel injury.

A separate, prospective trial involving almost 300 patients who had experienced blunt bowel/mesenteric injury at the Alfred hospital produced the following statistics on POCUS and CT scanning:

POCUS:

51% had free fluid on FAST scanning

CT scan:

Free gas was seen on 22% of patient’s scans
Bowel-wall thickening was seen in 31%
Fat and mesenteric stranding or hematoma was seen in 38%
And free fluid with no solid organ injury was seen in 43%

Additionally, patients who had an explorative laparotomy with resection or repair within 48 hours of presentation had a lower mortality than those after 48 hours.

The knowledge of these statistics and reiteration of them to the team who take over the patient’s care is crucial, such that a high index of suspicion for bowel injury is maintained and serial abdominal examinations are performed in the sub-acute setting to identify potential events and escalate surgical management early.

Mechanism of injury

The mesentery gets sheared off from the bowel, which is why patients may often appear well at first presentation - there is no laceration or perforation of the bowel wall. However over several hours, that section of bowel becomes ischemic and may perforate and cause a peritonitis. There is debate, however, around the specificity of CT in detecting hollow viscus injuries. While some guidelines suggest patients with blunt abdominal trauma should be admitted for clinical observation over a minimum period of 24 h since there is no investigation that can reliably rule out intra-abdominal injuries, other studies argue that newer helical CT machines have a very low false negative rate for detecting hollow viscus injury, provided the radiologist knows what to look for (as there are no pathognomic signs). Signs are non-specific and include bowel wall oedema, free air, free fluid, mesenteric haematoma etc.

There is, however, one sign that is associated with high rates of abdominal injury…

The Seatbelt Sign

…and it’s association with hollow viscus injury

The history of the seatbelt sign is interesting, as the term when first coined in reference to ecchymosis across the anterior abdomen in the old fashioned lap belts in cars before the 1940s. Since that time, most seatbelts have changed to the three point restraints that we know in cars today. Thus, the trend in injury seen with seatbelt signs has changed over the decades. When reading the literature on this, it’s important to take into account the definition given for seatbelt sign - colloquially the specificity for injury has decreased over time as the term has become more well known, as the range and severity of injury has increased over time.

One study showed that 64% of patients with seatbelt sign had an abdominal injury, 36% required operative intervention (roughly 23% with seatbelt sign) and 21% had small bowel perforation. Of those without seatbelt sign only 8% had significant intra-abdominal injury.

Pearls from our AITR - Dr Sean Croughan

Pay attention to the occult causes of shock

In the trauma patient, ruling out obstructive causes is the first priority, i.e. tension pneumothorax and cardiac tamponade.

Thereafter - find the bleeding. If haemorhagic shock has been ruled out, then you should look for spinal or neurogenic shock (covered in detail in S3E10 and S3E11).

Should a patient not respond to appropriate measures, don’t forget to consider other “medical causes” of shock, which may have precipitated the RTC in the first place. For example:

Cardiogenic shock (massive transfusion associated cardioplegia vs MI vs secondary to a beta blocked heart)
Anaphylaxis
Endocrine (hypoglycaemia or an Addisonian patient in an Addisonian crisis secondary to the stress response)

Predictors of need for operative intervention or massive transfusion

The prehospital shock index is often of the most significant predictors of the need for massive blood transfusion or ICU admission. In this case the patient had a HR 130, MAP of 70 with a wide pulse pressure of 60 and a shock index of 1.2.

Any episode of bradycardia

In trauma these are often associated with excessive vagal stimulation from peritoneal blood.

Episodes of transient hypotension

Patients with a single BP recording of <105 systolic were found to be >40% more likely to go for operative intervention/angiography/IR procedures in one study.

Shock index (SBP/HR)

A shock index of >1 is a bad sign.

Pulse Pressure

A narrow pulse pressure of <30 has been shown to be an early and accurate sign of significant haemorrhage and impending circulatory collapse. Pulse pressure is the systolic minus the diastolic blood pressure, and is usually in the range of 30-40. Specifically, the pre-hospital pulse pressure is a good predictor of severity of trauma, need for resuscitative thoracotomy and need for interventions.

Wide pulse pressures can be associated with aortic tears.

Transposition of the great arteries - a trauma perspective

We learned at handover that this patient’s medical history was significant for transposition of the great arteries. As such, this patient’s pulmonary blood flow would be almost entirely reliant on the difference between pulmonary and systemic pressures in body. It is crucial to avoid, where possible, anything that causes massive arterial vasodilation. Morphine wouldn’t be a great idea – and as we heard in both the case and AITR section, judicious boluses of fentanyl are a reasonable option. If further supplementation is needed for pain, one could consider cautious boluses of titrated ketamine. Consideration should also be given to this altered pathophysiology if an RSI is needed, where propofol should be avoided. As always, decisions re medications should be made in discussion with senior staff.

The RESTRIC Trial

Published earlier this year, this study was a cluster-randomized, crossover, non-inferiority multicenter trial of restrictive transfusion in trauma. It did not show a significant difference in mortality at 28 days for more restrictive Hb targets.

Packed Red Cells - not a resuscitative fluid

While we’re all familiar with the basic electrolyte breakdown of normal saline or hartmanns, the composition of packed red cells becomes increasingly relevant in the case of massive transfusion.

Each pack contains up to 40mmol of KCL, pH is around 6.5, Na content is around 110-115 and there is absolutely no calcium. Thus, if you give a massive, effective transfusion of say 10 units in an hour, you could be giving up to 400mmol of KCL.

There is an increasing awareness of Post Massive Transfusion Cardioplegia Syndrome in this specific setting, contributed to by hyperkalaemia, hypocalcaemia (both from acute coagulopathy of trauma and lack of Ca in red cells) and hypothermia.

References linked in text

S4E4: Road Traffic Collision - Trauma

The Pre-hospital alert

Ah, the sweet, sweet sound of the pre-hospital alert phone.