Beyond the trigger: recognising and responding to deteriorating patients

Track-and-trigger systems have quietly reshaped how we care for deteriorating patients. In the space of two decades, we've moved from a single "code blue" to tiered rapid response systems, and there's good evidence this safety net has reduced adverse events and cardiac arrests. But somewhere in that shift, it became easy to treat the score as the answer rather than the question.

The score starts the story. It doesn't finish it.

An early warning score is excellent at one thing: telling you when to look further. It provides a shared language of concern that everyone — nurse, registrar, MET team — understands, and it prompts escalation early and consistently. What it can't do is tell you what the deterioration means for the patient in front of you. It doesn't know their baseline, their physiological reserve, or their goals of care. For that, we still need to assess, and we still need to reason.

Normal vital signs don't always mean a stable patient

The most dangerous vital sign is the one that looks reassuring. The body compensates before it decompensates — respiratory rate climbs, the heart speeds up, peripheries clamp down — all to keep oxygenation and perfusion going. So, a "normal" blood pressure or saturation achieved through maximal compensation can sit in the white zone right up until the patient collapses. Oxygen saturations of 94% on room air are a very different story from 94% on ten litres. A blood pressure of 105/60 with a heart rate of 78 is not the same patient as 105/60 with a heart rate of 125.

This is why trend and context matter more than any single reading. Four questions help you look past the number: How much reserve does this patient have? Are they compensating to stay stable? What is the trend telling me? And have they reached the point where compensation is becoming decompensation?

Modifications add another layer. They reduce false alarms for patients whose chronic disease makes "abnormal" their normal — but modifications usually sit at the limit of reserve, leaving little room to detect real deterioration. They can be quietly, falsely reassuring.

Patterns of deterioration

Almost all acute deterioration traces to one of two failures: the body can't deliver enough oxygen and substrate to meet tissue demand, or the systems that keep the internal environment stable begin to fail. That's why a systems-based lens is more useful than a single number.

• Reduced consciousness points to the brain
  • stroke, hypoglycaemia, seizure, or the falling GCS of hypoxia and hypoperfusion.
• Compromised perfusion covers the circulatory causes
  • shock, haemorrhage, sepsis, arrhythmia, cardiac failure. 
• Impaired oxygenation spans the respiratory field
  • pneumonia, pulmonary oedema, PE, pneumothorax, opioid-induced respiratory depression. 
• Obstruction threatens the airway through reduced consciousness, secretions, oedema or foreign body.
• Systemic disturbances
  • sepsis, anaphylaxis, electrolyte and metabolic derangement destabilises the whole.

Reading deterioration this way follows the physiological hierarchy of survival that underpins ABCDE. A patent airway is useless without ventilation, ventilation useless without a circulation to carry oxygenated blood, and the brain is often first to show when any link in that chain gives way. Crucially, the body compensates before it decompensates, rising respiratory rate, tachycardia and vasoconstriction appear early, so recognising the pattern of compensation, not just the abnormal value, is what lets us see the collapse before it happens.

Common traps that stop us escalating

Cognitive shortcuts or heuristics exist because they work most of the time. In clinical practice they help us reach a workable decision faster, reduce cognitive load, point us to what is most likely going on, but anchoring locks us onto the first plausible explanation and quietly closes off the alternatives. Diagnostic overshadowing lets a known condition absorb every new symptom, so acute change gets written off as baseline. Normalisation of the abnormal creeps in when we see enough low blood pressures or fast heart rates that they stop alarming us, and we forget those numbers still carry risk. Premature closure stops the assessment the moment we have an answer that fits, rather than the one that's most dangerous. The traps aren't failures of knowledge; they're failures of attention. The safeguard is a habit: when something doesn't quite fit, go back to the patient, re-establish the baseline, check the medications and the trend, and ask what the worst thing this could reasonably be — and whether you've done enough to exclude it.

The gorilla in the room

None of this is purely about physiology. The famous selective-attention test — where a gorilla strolls through a game and half of us never see it — is a lesson in inattentional blindness. When we lock onto the obvious problem, we stop seeing the alternative. Good escalation is the antidote: escalate for the right reason, and communicate it in dot points, not a rambling story. Establish a shared mental model, thank the team, and build the kind of civil culture where someone feels safe saying, "Something isn't right."

Clinical judgement remains our best tool. The score just tells us when to pick it up.