The Cushing Triad (Cushing’s Triad or Cushing’s Reflex) is characterized by:
- Hypertension
- Bradycardia
- Irregular respirations – primarily Cheyne-Stokes breathing
This often signals the impending danger of brain herniation.
Shock – hypoperfusion – is what we often think about when it comes to trauma and significant illness. Shock is often characterized by:
- Decreased blood pressure
- Compensating (at least, attempting to compensate) increased heart rate
- Increased respiratory rate
Well, what if you find the opposite with your patient? What if they’re still hurt or still sick, but their vital signs seemingly don’t make sense?
In all actuality, they do make sense, but just not for the injury/illness – or triad – that you’re thinking of.
When your patient’s vital signs are seemingly the opposite of those presented with shock, you’re likely not dealing with shock; you’re dealing with an increase in intracranial pressure.
Intracranial pressure (ICP) is the pressure of the cerebrospinal fluid in the subarachnoid space, the space between the skull and the brain.
It’s not the trauma triad, nor is it Beck’s Triad that you’re concerned with here; it’s Cushing’s Triad.
Cushing’s Triad correlated into a slightly more simplistic form, can be directly compared (or contrasted) to that of shock. Instead of irregular respirations, I’ve thought of this as a decreased respiratory rate (or effectiveness), or bradypnea. As such, if shock equates to decreased blood pressure (hypotension), increased heart rate (tachycardia), and increased respiratory rate (tachypnea), then increased ICP is just the opposite:
- Increased blood pressure
- Decreased heart rate
- Decreased respiratory rate (effort)
While not necessarily the same as the Triad outlines, I think you get my point in this correlation.
Considering these either modified or true Triad findings, let’s take a look at a triad (three, that is) of case presentations for how Cushing’s Triad and increased intracranial pressure can manifest themself in different patient injuries/illnesses.
1. Cushing’s Triad case: Stroke
Your 73-year-old patient presents as acutely (recently) unconscious. She does not seem to have suffered any physical trauma, so you check her blood sugar level – which is 96 mg/dL. You don’t suspect an opioid overdose, so naloxone isn’t indicated here. Her husband was with the patient during this event and reports that she woke up with a headache this morning, which didn’t seem to subside with NSAID therapy. In fact, her headache intensified before she abruptly became unconscious. She presents with atypical (irregular, ineffective) breathing – which you manage with BVM ventilations – and her heart rate is in the 70s. Her blood pressure is 206/114, which is certainly not her norm.
Based on this information, what is your initial differential diagnosis?
If you’re shouting “stroke,” you’re probably right! Hemorrhagic strokes account for approximately 15% of strokes. They’re typically caused by some form of intracranial aneurysm (blood vessel rupture) or other form of vessel weakening. As blood leaks out of the ruptured or damaged vessel, it accumulates and compresses the surrounding brain tissue. Hemorrhagic strokes are typically categorized as intracerebral (within the brain) or subarachnoid (under the arachnoid membrane). Classic symptoms for hemorrhagic strokes – besides some form of face, arm or speech deficit – include sudden, severe headaches and/or sudden unresponsiveness.
2. Cushing’s Triad case: Mechanism of injury
You respond to a residence for a roofing contractor who fell from the roof of a two-story residence after slipping on the wet plywood surface. Your mid-30s patient is found in a supine position on the lawn and is unconscious. He does not show signs of external bleeding, but does have some minor bleeding coming from his mouth (tongue). He has agonal respirations, a heart rate in the 70s, and a blood pressure of 160/102.
While his vital signs aren’t glaringly directing you toward an increased ICP (yet), they’re not leading you down a path of decompensated shock, either.
The point of this case presentation is that – based on the mechanism of injury – there’s a high degree of suspicion for a head injury with this patient, and preloading your patient with a liter or two of normal saline may not be a great idea. In fact, it may be detrimental!
Sometimes, despite how bad the patient’s injuries may appear, the traditional approach of treating all trauma patients as shock patients (and giving all traumatic shock patients loads of fluid) may not be the best approach (and hopefully your protocols reflect this).
3. Cushing’s Triad case: Secondary head injury
It’s a winter afternoon and a group of teenagers are playing a recreational game of ice hockey on a local skating rink at a park. After nearly perfecting the knuckle puck slapshot, a final attempt leads to a disastrous event ... one of the players was struck in the face by the puck, knocking him out, and sending his upright body down to the ice (thump!). Now, the struck player has both a primary and secondary head injury from the event (primary being the puck, secondary being the ice).
You glide onto the ice with your cot, scoop stretcher or longboard and jump bag in tow to approach the unconscious patient. There’s blood in his mouth and around his face and head. He has snoring and gurgling respirations (from the blood) and a frantic crowd surrounds the scene. You don’t have much time to act, so you immediately begin suctioning his airway, scoop him up (while holding manual C-spine stabilization) and get him on the cot.
Once in the ambulance, you cut off his clothes, continue with your suctioning, and begin to ventilate the patient. A manual blood pressure indicates hypertension, with a systolic pressure of 190.
To intubate or not intubate? That is now the question!
Recognizing the signs of a head injury
Whether you’re able to remember that these presentations indicate “Cushing’s Triad” or not won’t make-or-break your patient care or patient care report documentation, but not recognizing its symptoms as a sign of head injury certainly will.
Again, not all trauma immediately leads you down the road to shock, so fluids may not be the right response (and even if it is shock, fluids may still not be the correct answer).
Whenever you’re facing quite the opposite presentation of shock, don’t think systemically; think with your head and recognize that the pressure you’re facing is not nearly as dangerous as the pressure your patient is facing.
This article, originally published on February 09, 2021, has been updated.
