How Decision Lab Works

In critical care, obvious answers are rare. We usually face competing choices, each backed by different facets of physiology, evidence, and clinical judgement.

CritiTAR Decision Lab is built for these exact moments. The TAR in the name defines the workflow for navigating these grey zones: Think, Analyse, and Reflect. Each edition drops you into a real-world ICU scenario. Commit to your decision before reading ahead. Click your choice to open a targeted debrief exploring the reasoning, clinical reality, and evidence for that option. The goal is not just finding the right answer. It is understanding why one path is more defensible than another, and where genuine uncertainty remains.

Today’s Decision

02:40. A 44-year-old man is brought in by his brother, who found him confused and vomiting at home. He has a history of heavy daily drinking, and has not eaten properly in three days after a bout of gastroenteritis. He’s tachycardic, tachypnoeic, and smells faintly of alcohol, though his last drink was reportedly the previous evening.

Current Assessment

Point-of-Care & Labs

• Bedside glucose: 78 mg/dL

• VBG: pH 7.22, HCO3 9, lactate 1.4, anion gap 24

• Urine ketones: strongly positive

The resident who reviews the ABG in isolation writes the order: start an insulin infusion, DKA protocol.

What do you do?

A. Agree and proceed with the resident’s order to start an insulin infusion.

B. Hold the insulin. Administer normal saline and encourage oral refeeding.

C. Hold the insulin. Check an HbA1c and home medication list for SGLT2 inhibitors before acting.

D. Hold the insulin. Give thiamine, start IV dextrose, and provide volume resuscitation.

Before you click

Pick the option you would actually order on rounds. There are no trick questions.

A few years back, a Sunday afternoon, routine rounds. A call from the ER: they needed help securing an airway on a patient who seemed to be continuously seizing. I went down and found a young man, obese, obstructing. He had already received one dose of benzodiazepine. Knowing how often we underdose out of fear of airway compromise, I gave a second dose and secured the airway. His family said he had been reasonably fine, apart from some generalised weakness and a fever spike a few days back.

We have all stood at the foot of the bed watching the monitor as a patient goes through our initial algorithms. I have seen my share of autoimmune and infectious encephalitis cases that test the absolute limits of our patience. I still vividly remember a young man with dengue encephalitis who did not wake up for more than a month, yet we eventually walked him out the door to go home. Then there was a case of new-onset refractory status epilepticus that I managed remotely during my time working as a Tele-Intensivist; it took weeks of relentless medical management across the screens before the patient finally turned the corner and did remarkably well.

These experiences reinforce a fundamental truth in neurocritical care: the brain has a profound capacity for recovery, provided we maintain the rest of the organ functions while trying to save it.

By the time his airway was secured, the biological clock had already been running for several minutes. Managing these prolonged cases requires us to navigate a massive grey zone where we must simultaneously investigate and treat. When a patient arrives in status epilepticus, time is our biggest biological enemy. The International League Against Epilepsy defines the critical window starting at five minutes, the point where a generalised convulsion is unlikely to self-terminate, and ending at thirty minutes, where the risk of irreversible neuronal injury increases substantially. What happens in the brain during those minutes explains exactly why our first and second-line drugs so often fail.

Long before a patient reaches the point of ketamine and immunotherapy, most of the damage in status epilepticus has already been done by simple underdosing. Adequately dosed benzodiazepines terminate around seventy per cent of status epilepticus, and RAMPART showed intramuscular midazolam is non-inferior to intravenous lorazepam, which matters when IV access is the thing slowing you down. But adequate dosing is the exception, not the rule. In one large adult cohort, not a single patient received an adequate first-line midazolam dose. We call it benzodiazepine resistance far more often than we call it benzodiazepine underdosing, and the two get confused constantly at the bedside, usually out of exactly the fear that a second dose would compromise an airway that was, in reality, already compromised by the seizure itself. Ongoing untreated seizure activity carries a higher respiratory-depression risk than an appropriately dosed rescue dose does. The second dose did not put that airway at risk. It gave me one worth securing.

Once that first window closes, the second-line choice matters less than we tend to argue about in rounds. ESETT put levetiracetam, valproate and fosphenytoin head to head and found them equivalent, each around forty-five to fifty per cent effective. The decision comes down to contraindications and logistics, not conviction.

Once he was sedated and intubated, it is often easier to think the seizures have subsided until we realise that a considerable proportion of them have ongoing ictal activity visible on EEG. In the ICU, roughly ninety per cent of ongoing seizures are nonconvulsive, and of the patients who do show abnormal movements on the unit, about three-quarters turn out not to be seizing at all. EEG is the only instrument that closes that gap, and it is very often the instrument that is missing exactly when you need it most.

This rapid receptor trafficking is the biological reason why the exact same brain that would have responded beautifully to a benzodiazepine at minute five becomes pharmacoresistant by minute thirty. When we escalate to continuous infusions in the ICU, we inevitably hit a haemodynamic wall. We push higher doses of propofol or reach for barbiturates like pentobarbital or thiopental, but these lead to profound hypotension, ileus, and severe immunosuppression. This is where our understanding of the changing receptor landscape should change our management. Because the seizing brain has massively upregulated its NMDA receptors, adding a targeted NMDA antagonist like ketamine makes physiological sense. Ketamine allows us to attack the runaway excitation directly without the devastating cardiovascular and respiratory depression that comes from pushing higher doses of traditional sedatives.

Pharmacology alone will not save the patient, which brings us back to the grey zone of parallel investigation. In cases of new-onset refractory status epilepticus, where there is no clear structural or toxic-metabolic cause, we cannot afford to wait for our anaesthetics to fully fail before we start hunting for the underlying fire. Up to fifteen per cent of these cases are driven by antibody-mediated autoimmune encephalitis. We have to start immunotherapy early. High-dose intravenous steroids, intravenous immunoglobulin, or plasma exchange should be initiated within 72 hours of suspicion. We have to send off the extensive diagnostics for rare infectious and autoimmune panels while simultaneously suppressing the seizures and supporting the failing haemodynamics. It is a highly challenging physiological balancing act, but recognising the shifting biology of the seizing brain, leveraging agents like ketamine to spare the cardiovascular system, and respecting the absolute urgency of early immunotherapy is what gives these patients the weeks they sometimes need to finally wake up.

His fever spikes and generalised weakness were exactly this pattern: no antecedent epilepsy, no clear acute cause, a story that pointed toward autoimmune or post-infectious encephalitis rather than a one-off convulsion. We did not wait for the anaesthetics to fail. IV methylprednisolone went in once it was clear this was not going to resolve on antiseizure medication alone.

There is a version of this problem that never shows up in a trial.

Families do not read the seizure the way we read it. They hear “status” or “coma due to status,” and what they take from those words is that once we stop the seizure, or once we give the antiepileptic, he should wake up. That is a reasonable inference from ordinary language, and it is wrong for this disease.

His family asked, repeatedly, why he wasn’t opening his eyes once the seizures were controlled. There is no good short answer, because the honest one involves receptor trafficking, sedative half-lives, and a recovery timeline measured in weeks rather than hours, none of which fits into a corridor conversation on day two.

He woke up after a month. He needed a long rehabilitation course after that. Refractory status carries something close to a one-in-four mortality, super-refractory nearer two-in-five, and those numbers have barely moved in three decades of new drugs. We sent him home in the end. That outcome was never guaranteed. It was earned by weeks of persistence and patience, and by a family who stayed even when our answers weren’t the ones they wanted.

Selected References:

• Trinka E et al. A definition and classification of status epilepticus. Epilepsia. 2015;56:1515–23.

• Gettings JV, Mohammad Alizadeh Chafjiri F, Patel AA, Shorvon S, Goodkin HP, Loddenkemper T. Diagnosis and management of status epilepticus: improving the status quo. Lancet Neurol. 2024.

• Rossetti AO, Claassen J, Gaspard N. Status epilepticus in the ICU. Intensive Care Med. 2024;50:1–16.

• Alshehri RS, Alrawaili MS, Zawawi BMH, Alzahrany M, Habib AH. Pathophysiology of Status Epilepticus Revisited. Int J Mol Sci. 2025;26:7502.

• Rai S, Drislane FW. Treatment of Refractory and Super-refractory Status Epilepticus. Neurotherapeutics. 2018;15:697-712.

• Kapur J et al. Randomized trial of three anticonvulsant medications for status epilepticus (ESETT). N Engl J Med. 2019;381:2103–13.

• Wickström R et al. International consensus recommendations for NORSE/FIRES. Epilepsia. 2022;63:2827–39.

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Going back in time, I still remember laughing at a reel, or perhaps it was a WhatsApp forward. It showed people somewhere in China suddenly collapsing on the streets from what was believed to be a viral illness. Like many others, I dismissed it. The videos looked too dramatic to be true.

Then came the announcements from the WHO. Gradually, the medical fraternity across the world started taking it seriously. We had seen outbreaks before, but they rarely crossed geographical boundaries with such speed. There were also theories that climate or warmer weather might protect countries like India. Many of us wanted to believe that.

Soon hospitals were asked to prepare. Protocols were discussed. We began reading whatever little evidence was available, trying to understand a disease that the world itself was only beginning to know. Then, almost like a tsunami, the numbers started rising. What initially seemed like isolated reports suddenly felt like we were only seeing the tip of the iceberg. We began wondering not whether COVID would come, but whether we were prepared for what was coming.

The lockdown followed.

For perhaps the first time, our roads fell silent. As healthcare workers, we carried passes that allowed us to travel. Even if we wanted to drive slowly, we often reached the hospital in barely a quarter of the usual time. The city had paused. We couldn’t.

Hospitals transformed almost overnight. Staff learnt the now familiar rituals of donning and doffing PPE. Screening areas appeared where none had existed before. Disposable supplies were stacked everywhere. The hospital looked white because of the PPE.

Yet, to me, that was the beginning of a grey era.

A gloomy phase that hung over everyone. Suddenly COVID was the only thing people spoke about. How it spread. How to prevent it. Which medicine worked. How to improve immunity. Some dismissed it as an illusion. Others feared it would devastate a country like ours. Most of us probably lived somewhere in between, watching it unfold, believing it, yet hoping we were wrong.

As patients started arriving in larger numbers, our days revolved around triaging. Every bed mattered. Every oxygen port mattered. Every decision mattered. Resources had to be planned, utilised and constantly reallocated. It felt like solving a puzzle that kept changing its shape as demand slowly overtook supply.

Calls started pouring in. Friends, relatives and colleagues. Someone knew someone who needed an ICU bed. Could we reserve one? Could we somehow arrange something?

The question, “What if I get COVID?” did cross my mind occasionally. But I didn’t dwell on it much. There simply wasn’t enough time. Like everyone else around me, I was too occupied trying to solve the next problem before another one arrived.

The numbers kept rising.

Television channels almost competed to describe the worst possible scenario, looping endless drone footage of overflowing graveyards and crematoriums. Social media flooded with case counts, mortality figures and predictions. WhatsApp groups multiplied overnight. One for administration. One for ICU discussions. Another for triage. Yet another for new guidelines. Alongside them came an endless stream of miracle cures, home remedies and confident opinions from people who had never stepped inside an ICU.

My mother texted me one day saying a new medicine seemed to work, asking if we were using it. Looking back, that one message probably captures those days. For perhaps the first time, scientific evidence had become part of everyday conversation.

Ironically, the evidence itself was changing every day. New studies appeared almost overnight. Guidelines were revised repeatedly. We were reading and simultaneously changing our practices.

Then there was the PPE.

The first time I wore full PPE with an industrial-grade respirator, it felt almost unreal, as though I was stepping onto the moon rather than into an ICU. You became acutely aware of your own breathing. Sweat collected inside the suit. Hours felt much longer than they really were. If it felt difficult for us, I often wondered how nurses managed, spending far longer inside than anyone else.

The ICU itself had changed.

Almost every patient was on some form of oxygen support. Monitors beeped continuously. Eyes kept drifting towards the plethysmograph and the oxygen saturation. Around them stood people dressed head to toe in white PPE, their faces hidden behind masks and shields.

Strangely, despite all that white, I never remember the ICU as white.

To me, it was always grey.

Not black, because there was still hope.

Not white either, because uncertainty had settled into every corner.

As the weeks passed and the numbers grew, that grey only became darker.

Initially, COVID seemed to be just another respiratory illness. Then came strokes, thrombotic complications, cardiac involvement and inflammatory syndromes. The disease kept revealing new faces, and each time we thought we had begun to understand it, it surprised us again.

Beyond the PPE, the protocols and the planning, there were people living through uncertainty. My attention kept drifting towards the fear in our patients’ eyes.

Did we address that enough?

I still don’t know.

We hid behind layers of PPE. We could speak to them, reassure them and explain things. But could they even see our expressions? Could they tell when we were genuinely happy that they were improving? Or did we simply look like strangers dressed as astronauts, walking from one bed to the next?

Every patient had a story.

Many remained awake for much of their illness. They watched the monitor constantly. The blue oxygen saturation number became their source of reassurance. Sometimes, before I even reached the bedside, they would point towards it. A fall of just a few points was enough to make them anxious. They did not have families sitting beside them, holding their hand or telling them everything would be alright.

Video calls became the closest substitute.

As we walked past, we often overheard families trying to sound hopeful. They would tell their loved ones that everything was alright outside and that they would be home soon. Both sides knew the uncertainty, yet both tried to protect the other from it.

I remember an elderly couple admitted to our ICU. Their beds were opposite each other. They stayed with us for several days. Every conversation somehow ended with a question about the other.

“Has he eaten?”

“Is she alright today?”

Even while struggling to breathe, each was more worried about the other than themselves.

Sometimes one of them would ask if a bed could somehow be arranged for another family member who was unwell elsewhere. In those moments, I realised that while we were trying to manage an overflowing ICU, entire families were fighting the same battle in different places.

A young woman arrived late to the hospital. As she was being shifted into the ICU, I watched her breathing change almost in front of my eyes. Within moments she deteriorated.

She didn’t survive.

Most ICU patients never witness an ICU.

COVID patients did.

They saw the patient in the next bed deteriorate. They heard the alarms. They watched emergency intubations. Sometimes they saw a bed become empty.

I often wondered what went through their minds.

Did they worry that the next alarm would be theirs?

Did they look at the patient in the neighbouring bed being intubated and wonder if they would be next?

Did every fluctuation on the monitor make them fear that their illness had taken a turn for the worse?

I don’t know.

I still don’t know.

The waves eventually settled. The roads filled up again. The drive to the hospital was no longer fifteen minutes. PPE returned to shelves instead of becoming a part of our daily uniform. Families walked into hospitals once again. Video calls became less frequent. Life, at least on the surface, looked familiar.

Slowly, we learnt more. Vaccines arrived. Treatments evolved. The fear that had once occupied every news channel gradually gave way to other headlines.

Yet some things quietly stayed behind. Even today, we casually divide time into pre-COVID and post-COVID without thinking. It has become a marker of time for an entire generation of healthcare workers.

When I look back, I don’t remember COVID as a collection of guidelines, drugs or statistics.

I remember empty roads leading to a busy hospital, those white suits that somehow looked only grey, those patients looking anxiously at the monitors for reassurance, families waiting for that video call and some stories which were never told.

The roads are busy again. Hospitals have found their rhythm again. Life has moved on.

But every now and then, when I see a patient glance anxiously at a pulse oximeter, or a forwarded message confidently claiming to have all the answers, I find myself going back to those shades of grey.

How Decision Lab Works

In critical care, obvious answers are rare. We usually face competing choices, each backed by different facets of physiology, evidence, and clinical judgement.

CritiTAR Decision Lab is built for these exact moments. The TAR in the name defines the workflow for navigating these grey zones: Think, Analyse, and Reflect. Each edition drops you into a real-world ICU scenario. Commit to your decision before reading ahead. Click your choice to open a targeted debrief exploring the reasoning, clinical reality, and evidence for that option. The goal is not just finding the right answer. It is understanding why one path is more defensible than another, and where genuine uncertainty remains.

Today’s Decision

A 58-year-old man with known coronary artery disease (LAD drug-eluting stent placed four years ago, on aspirin) is 48 hours into his ICU admission for urosepsis complicated by septic shock.

The overall clinical picture appears to be improving. Source control was achieved with a ureteric stent. Blood cultures grew Escherichia coli, and antibiotics were narrowed accordingly. Over the past 48 hours, his norepinephrine requirement has dropped from 0.35 to 0.18 mcg/kg/min.

Current Assessment

Haemodynamics

• MAP: 70 mmHg

• Heart rate: 96 beats/min

• Lactate: 4.2 → 1.8 mmol/L

• Urine output: 0.7–1.0 mL/kg/hr

Renal Function

• Creatinine: 1.3 → 1.5 → 1.7 mg/dL

Point-of-Care Echocardiography

• Hyperdynamic left ventricle (visually estimated EF >65%)

• No regional wall motion abnormalities

• No pericardial effusion

ECG

• Sinus tachycardia

• No new ST-segment changes

• No new T-wave inversions

He is lightly sedated, wakes appropriately to voice, follows simple commands, and shows no clinical signs of ongoing myocardial ischaemia.

Then, one result catches your attention.

hs-Troponin I

(Upper reference limit: 0.028 ng/mL)

• Admission: 0.18 ng/mL

• 24 hours: 0.52 ng/mL

• 48 hours: 0.86 ng/mL

The troponin continues to rise. The patient continues to improve.

How do you interpret this discordance, and what is your next move?

• A. Request an urgent cardiology consultation to consider coronary angiography.

• B. Treat as an NSTEMI by escalating antithrombotic therapy with ticagrelor and therapeutic anticoagulation.

• C. Stop measuring troponin. The patient is improving, and this is simply sepsis-related myocardial injury.

• D. Continue serial troponins to 72 hours, repeat echocardiography tomorrow, monitor renal function closely, and withhold ACS therapy unless new evidence of myocardial ischaemia emerges.

  ---

Before you click

Pick the option you would actually order on rounds. There are no trick questions.

Yesterday I went back to the hospital where I trained. It had been years.

The moment I walked into the unit, the memories hit before anything else. The jokes. The long patient discussions in the duty room. The exhaustion you share at 3 AM.

If you trained in an ICU, you already know this.

The centre of every day was morning rounds. Between our three core mentors there were decades of ICU wisdom moving from bed to bed. They were meticulous with every single detail, checking everything right down to the monitor records. Then they broke clinical problems down in front of us, at the bedside, in real time.

After rounds, coffee in the duty room. One trainee always stood beside the container, filled cups, and passed them down the line. We discussed radiology every single day over that coffee. That habit is still in me.

Our Head of Department ran on sincerity. He treated the patient, not the monitor. In situations where there was still something to fight for, he was the last man to give up. He also showed us how to maintain composure with grieving families. That is harder than most procedures.

Our second mentor constantly pushed us to expand our own thinking. He never shied away from asking the right question, however difficult, and he expected the same from us. He made sure we never assumed our way to a diagnosis, teaching us that every conclusion had to be earned through logic. That standard is what made him the clinician everyone wanted to become.

Our third mentor taught us method. When the night shift had taken everything out of us and the handover was fragmenting, he would slow us down without judgment. Then walk us through until the case was organised. He showed us that method is what holds when everything else is gone.

Three distinct styles. The combination is what made the training complete.

When my old colleagues and I walked through the unit yesterday, we stopped at specific beds. We didn’t see equipment. We saw the patients who had been in those beds. The ones who made it and the ones who couldn’t.

Every bed had a story.

We also had a father figure in the unit, CP, who called me son. The first thing he gave me was Primum non nocere. First, do no harm. I carry that more than most things from those years.

And Poo, our colleague who never left and still works there. Watching her now as a mature, fiercely competent intensivist, who also happens to be an Instagram reel queen, is a wonderful reminder of how far we have all come.

If you trained in an ICU, you are probably thinking about your own unit right now. But this is not only a story about critical care. Anyone shaped in a high-stakes environment, by mentors who gave more than the job required, and alongside colleagues who helped shape who they became, will find something familiar here.

The setting changes. What it does to you doesn’t.

You remember the one who never gave up when something was still worth fighting for. The one who thought in ways you still aspire to. The one who showed you that method, held steady in the worst moments, is what separates good outcomes from lucky ones.

It is almost a reflex in neurocritical care. The moment a post-thrombectomy patient arrives in the ICU and their systolic blood pressure touches 180 mmHg, the antihypertensive infusion starts. We operate on the ingrained assumption that clamping down blood pressure is the definitive way to prevent reperfusion haemorrhage.

Yet as vessel recanalisation rates improve, a difficult clinical reality is emerging. Reopening the artery does not guarantee tissue recovery. Our rigid blood pressure algorithms might be compromising recovery in tissue that remains dependent on collateral flow.

The Problem With Intensive Lowering

The physiological argument for driving blood pressure down is straightforward. An ischaemic vascular bed loses autoregulation and becomes pressure-passive. Systemic hypertension hitting that fragile bed drives fluid across a disrupted blood-brain barrier, leading to vasogenic oedema and haemorrhagic transformation.

However, the clinical strategy of intensive blood pressure lowering has consistently failed to deliver these theoretical benefits. Multiple randomised controlled trials attempted to prove that lower blood pressure targets yield better outcomes. They all failed, though the mechanisms behind those failures remain uncertain.

Take BP-TARGET, the first dedicated trial in this space. It enrolled 324 recanalised patients across four French academic centres, pitting an intensive systolic target of 100 - 129 mmHg against a standard 130 - 185 mmHg over 24 hours. The actual achieved pressures averaged 128 mmHg versus 138 mmHg. The investigators themselves acknowledged that this 10 mmHg separation was modest. The primary endpoint was radiographic intraparenchymal haemorrhage at 24 - 36 hours. There was no significant difference between the groups. The trial was not powered to detect differences in functional outcomes. A neutral result combined with a narrow pharmacological separation left the hypothesis only partially tested.

ENCHANTED2/MT was much larger. It enrolled 821 patients across 44 hospitals in China, aiming for a systolic pressure below 120 mmHg versus a standard target of 140 - 180 mmHg for 72 hours. The trial was halted at under 40% enrollment because it crossed a predefined safety threshold. At 90 days, the intensive group had a significantly higher likelihood of poor functional outcome (OR 1.37; 95% CI 1.07 - 1.76). There was no difference in symptomatic intracranial haemorrhage. Aggressive lowering worsened functional outcomes without preventing the bleeds it was intended to avoid.

OPTIMAL-BP tested a softer intensive target of below 140 mmHg against a conventional 140 - 180 mmHg target for 24 hours across 19 South Korean stroke centres. The intensive arm again demonstrated worse functional outcomes. A subsequent post-hoc mediation analysis provided an important clue. Much of the observed harm appeared to be mediated by time-related blood pressure variability. The problem may not simply be the absolute blood pressure achieved, but the physiological instability created while attempting to force blood pressure into a lower range.

BEST-II approached the question differently. This phase 2 futility trial across three US comprehensive stroke centres tested three systolic targets (<140, <160, and ≤180 mmHg) using intravenous nicardipine over 24 hours. The probability that a future definitive trial would demonstrate benefit was low: 25% for the lowest target group and 14% for the middle target group. The results provided little justification for pursuing a large confirmatory trial of intensive lowering.

In 2026, Hashmi and colleagues pooled six randomised trials in a meta-analysis published in the Journal of the American Heart Association. The pooled results pointed in the same direction as the individual studies. Intensive blood pressure control reduced the odds of achieving a good functional outcome (OR 0.70; 95% CI 0.54 - 0.91) and increased all-cause mortality, without significantly reducing symptomatic intracranial haemorrhage.

If haemorrhage is not reduced, yet outcomes worsen, then injury may be occurring through mechanisms unrelated to bleeding. One possible explanation is that aggressive blood pressure reduction compromises perfusion to collateral-dependent tissue that remains incompletely reperfused.

The HOPE Trial: A Reperfusion-Guided Approach

The HOPE trial (JAMA Neurology, 2026) reframes the entire discussion. Rather than asking how low blood pressure should go, the investigators asked whether blood pressure targets should depend on the degree of reperfusion achieved.

Conducted across 11 Spanish stroke centres and stopped early for funding after enrolling 440 patients, HOPE randomised patients with successful recanalisation (mTICI 2b or higher) to either standard guideline care (systolic blood pressure ≤180 mmHg) or a reperfusion-stratified haemodynamic strategy maintained for 72 hours.

The rationale was straightforward. Patients with near-complete or complete reperfusion (mTICI 2c–3) were presumed to face a greater risk of reperfusion injury and were assigned a systolic target of 100 -140 mmHg. Patients with partial reperfusion (mTICI 2b), where vulnerable tissue might still depend on collateral flow, were assigned a higher target range of 140 - 160 mmHg.

This was not simply a blood pressure lowering protocol. Vasopressors were used when necessary to maintain blood pressure within the assigned range. It was a true haemodynamic range trial.

At 90 days, 60.0% of patients in the reperfusion-guided group achieved functional independence (mRS 0–2) compared with 47.1% in the standard-care group. This translated to a 13.3% absolute risk difference (95% CI 4.1 - 22.6; P = 0.005). Haemorrhagic transformation occurred less frequently in the targeted group (22.3% vs 31.6%; OR 0.62, 95% CI 0.41 - 0.95). Rates of symptomatic intracranial haemorrhage (3.5% vs 3.9%) and 90-day mortality (15.4% vs 15.6%) were nearly identical.

While HOPE provides the first positive randomised evidence supporting a reperfusion-guided haemodynamic strategy after thrombectomy, its findings must be interpreted with caution. The trial was stopped early, was conducted within a single country, and has not yet been externally replicated.

The Unanswered Questions

Before institutional protocols are rewritten, several important questions remain.

First, what exactly drove the benefit?

HOPE combined reperfusion-stratified blood pressure ceilings with protocolised maintenance of blood pressure within a predefined range. ENCHANTED2/MT, OPTIMAL-BP, and BEST-II focused primarily on lowering pressure and did not protocolise a haemodynamic floor in the same way. Did HOPE succeed because of the tailored upper targets, the protection from hypotension, or the combination of both? The answer determines whether this intervention is fundamentally about lowering blood pressure or preserving cerebral perfusion.

Second, the vascular anatomy differs substantially across these trials. ENCHANTED2/MT and OPTIMAL-BP enrolled predominantly Asian populations, where intracranial atherosclerotic disease (ICAD) approaches 40%. In White populations, prevalence is closer to 10%. The higher prevalence of ICAD raises the possibility that residual flow-limiting stenosis modifies the haemodynamic response to aggressive blood pressure lowering. HOPE, conducted in Spain, deliberately excluded patients considered at risk of haemodynamic infarction due to non-revascularised intra- or extracranial stenosis. Whether the benefits observed in HOPE can be safely extrapolated to ICAD-heavy populations remains uncertain.

Finally, the application to large ischaemic cores remains largely unexplored. HOPE excluded patients with ASPECTS below 6. Most prior blood pressure trials similarly enrolled patients with small or moderate infarct cores. Yet a patient with an ASPECTS of 3–5 who achieves TICI 2b/3 reperfusion presents perhaps the most challenging haemodynamic problem in the neuro-ICU. Their risk of reperfusion haemorrhage is high. The haemodynamic requirements of these patients remain poorly defined. The margin between under-perfusion and over-perfusion is exceptionally narrow.

We do not know whether a target of 100 - 140 mmHg is appropriate in this setting. Current ASA/AHA guidance cautions against actively targeting systolic pressures below 140 mmHg because of the harm observed in prior trials. HOPE, however, protocolised vasopressor-supported targets within precisely that range for patients with TICI 2c/3 reperfusion. The evidence needed to reconcile these seemingly conflicting approaches does not yet exist.

CritiTAR Reflection

We are moving beyond rigid algorithms toward more nuanced, physiology-informed care. Replacing a universal blood pressure ceiling with a universal blood pressure range is not precision medicine. True precision requires us to consider the recanalisation grade, infarct core size, collateral status, and residual vascular anatomy, then tailor haemodynamics accordingly.

References

BP-TARGET Trial: Mazighi M, Richard S, Lapergue B, et al. Safety and efficacy of intensive blood pressure lowering after successful endovascular therapy in acute ischaemic stroke. The Lancet Neurology. 2021.

ENCHANTED2/MT Trial: Yang P, Song L, Zhang Y, et al. Intensive blood pressure control after endovascular thrombectomy for acute ischaemic stroke. The Lancet. 2022.

OPTIMAL-BP Trial: Nam HS, Kim YD, Heo J, et al. Intensive vs Conventional Blood Pressure Lowering After Endovascular Thrombectomy in Acute Ischemic Stroke. JAMA. 2023.

OPTIMAL-BP Post-Hoc (BP Variability): Chang JY, Park JY, Song JY, et al. Mediation of Time-Related Blood Pressure Variability on Intensive Blood Pressure Lowering and Functional Outcomes Post Endovascular Therapy. Journal of the American Heart Association. 2025.

BEST-II Trial: Mistry EA, Hart KW, Davis LT, et al. Blood Pressure Management After Endovascular Therapy for Acute Ischemic Stroke: The BEST-II Randomized Clinical Trial. JAMA. 2023.

Meta-Analysis: Hashmi TM, et al. Intensive Versus Standard Blood Pressure Control After Endovascular Thrombectomy in Acute Ischemic Stroke: A Meta-Analysis of Randomized Controlled Trials. Journal of the American Heart Association. 2026.

HOPE Trial: Camps-Renom P, Guasch-Jiménez M, Álvarez-Cienfuegos J, et al. Personalized Blood Pressure Targeting After Endovascular Therapy for Acute Ischemic Stroke: A Randomized Clinical Trial. JAMA Neurology. 2026.

You are on a night shift.

A patient with aneurysmal subarachnoid haemorrhage, Hunt-Hess III, is on day four. The aneurysm has been coiled. The nurse calls because the patient has developed new right-sided weakness. The TCD shows an MCA velocity of 200 cm/s.

You review the medication chart and note that nimodipine has been held twice because the MAP keeps drifting downward.

The resident asks a reasonable question.

Do we really need this drug?

It is worth asking because the closer you look at nimodipine, the stranger the story becomes.

We know it improves outcome after aneurysmal SAH. We have known that since the British Aneurysm Nimodipine Trial in 1989.

What we remain less certain about is how it works, how aggressively we should support blood pressure to continue it, whether intravenous administration offers any advantage, and why twenty-one days became the standard duration of treatment.

For a drug that carries a Class I guideline recommendation, it occupies a surprisingly large grey zone.

DCI Is Not Vasospasm

For years, delayed cerebral ischaemia and angiographic vasospasm were treated as the same process.

The logic was straightforward. Blood enters the subarachnoid space, irritates cerebral arteries, causes vasoconstriction, reduces cerebral blood flow, and eventually produces ischaemia.

If that model were correct, eliminating vasospasm should improve neurological outcome.

The CONSCIOUS-1 trial challenged that assumption.

It demonstrated that clazosentan significantly reduced angiographic vasospasm. The subsequent phase III trials, CONSCIOUS-2 and CONSCIOUS-3, continued to show improvements in angiographic vasospasm, but the outcomes did not follow.

Despite better-looking arteries, patients did not experience the expected improvements in functional recovery.

The findings were difficult to ignore.

Vasospasm matters, but it is not the whole story.

Over the last decade, delayed cerebral ischaemia has evolved from a purely vascular diagnosis into a multifactorial syndrome involving early brain injury, cortical spreading depolarisations, microvascular dysfunction, microthrombosis, neuroinflammation, and impaired autoregulation.

That distinction changes how we think about nimodipine.

If Nimodipine Works, What Is It Actually Doing?

The British Aneurysm Nimodipine Trial demonstrated a reduction in cerebral infarction and poor neurological outcome. Multiple subsequent studies and meta-analyses have reinforced the finding.

Nimodipine works.

The paradox is that its clinical benefit appears disproportionate to any effect on angiographic vasospasm alone.

Repeated studies have failed to show a consistent relationship between reductions in angiographic vasospasm and the magnitude of clinical benefit observed with nimodipine.

That observation has shifted attention toward other mechanisms.

Current evidence suggests nimodipine may reduce the frequency of cortical spreading depolarisations, improve collateral microcirculatory flow, and limit calcium-mediated neuronal injury. Experimental data have also suggested effects on endogenous fibrinolytic activity and microthrombus formation. More recent pharmacokinetic studies have suggested that cerebrospinal fluid concentrations may correlate more closely with outcome than plasma concentrations.

The truth is that we still do not know which mechanism matters most.

Thirty-five years after the British Aneurysm Nimodipine Trial, the drug continues to improve outcomes while its dominant mechanism remains uncertain.

The Noradrenaline Paradox

The uncertainty becomes more obvious at the bedside.

We prescribe nimodipine to reduce the risk of delayed cerebral ischaemia.

Blood pressure falls. CPP falls. Noradrenaline is started, and before long the dose begins to climb.

Then somebody asks whether the nimodipine dose should be reduced because the patient is requiring too much vasopressor support.

Every neurointensivist has been part of this discussion.

The 2023 AHA/ASA guidelines strongly recommend enteral nimodipine and acknowledge that induced hypertension may be beneficial in patients with symptomatic delayed cerebral ischaemia. Importantly, induced hypertension is the only component of the historical triple-H strategy shown to improve cerebral perfusion. Both hypervolaemia and haemodilution have largely fallen out of favour. The Neurocritical Care Society similarly supports nimodipine therapy.

This is where the grey zone begins.

Delayed cerebral ischaemia is heterogeneous. Haemodynamic goals are often individualised according to the neurological examination, TCD findings, ICP, autoregulatory status, and available multimodal monitoring.

The guidelines support maintaining cerebral perfusion, but they stop short of defining exactly how that should be achieved for an individual patient.

Ask ten neurointensivists what CPP should be maintained during delayed cerebral ischaemia and you may receive ten different answers.

Some centres target a CPP above 70 mmHg. Others focus on MAP augmentation. Some individualise haemodynamic goals using TCD trends, ICP, brain tissue oxygen monitoring, or simply the patient’s neurological examination.

The challenge is that individualisation still requires a decision at the bedside.

How much blood pressure augmentation is enough?

How much noradrenaline is too much?

At what point should nimodipine dose reduction be considered?

These questions remain far less certain than the recommendation to prescribe nimodipine itself.

The available data suggest that abandoning nimodipine may not be the best answer.

In a two-centre retrospective study of 397 SAH patients, Pala and colleagues found that nimodipine exposure was an independent predictor of favourable six-month outcome, even in patients who required vasopressor support to maintain perfusion pressure.

However, interpreting these findings is not straightforward. Clinicians often reduce or withhold nimodipine when patients deteriorate neurologically or require escalating vasopressor support. Whether dose reduction contributes to poor outcome, or whether worsening brain injury drives dose reduction, remains difficult to determine.

The causality remains uncertain, but the physiology suggests that maintaining nimodipine while supporting perfusion may be preferable to reflexively discontinuing the drug.

The Twenty-One-Day Question

Most protocols continue nimodipine for twenty-one days.

The number feels precise.

In reality, the evidence is less precise than many assume.

The twenty-one-day duration originated from the landmark trials and became embedded in clinical practice during an era when vasospasm was considered the dominant driver of delayed neurological deterioration.

More recently, investigators have started questioning whether every patient requires a full twenty-one-day course.

A 2016 study by Cho and colleagues reported no significant difference in outcome between shortened and standard treatment courses in selected patients. Similar observations were later reported by Sokolowski and colleagues.

None of these studies are strong enough to change practice.

They do, however, remind us that tradition and evidence are not always the same thing.

Whether every patient requires twenty-one days of treatment remains an open question.

What About Intravenous Nimodipine?

Intravenous nimodipine appears attractive when enteral absorption becomes unreliable.

It provides more predictable plasma concentrations, which sounds attractive when enteral absorption is uncertain.

Yet higher plasma concentrations have never convincingly translated into better neurological outcomes.

What intravenous nimodipine consistently delivers is a greater risk of hypotension and a larger vasopressor burden.

Recent pharmacokinetic studies have raised the possibility that CSF exposure matters more than plasma exposure. Yet even attempts to deliver higher concentrations directly into the CSF have failed to produce the clinical benefits many expected.

Once again, the certainty disappears.

The CritiTAR Northstar

Nimodipine occupies a unique position in neurocritical care.

It improves outcome, yet we still do not fully understand how.

Its clinical benefit appears greater than would be expected from any effect on angiographic vasospasm alone. We individualise haemodynamic targets, yet there is no universally accepted CPP goal during delayed cerebral ischaemia. We continue treatment for twenty-one days, though the evidence supporting that exact duration is less robust than many assume.

And not infrequently, we find ourselves using noradrenaline to counteract the haemodynamic effects of the very drug we are trying to continue.

Thirty-five years later, nimodipine remains one of the few therapies in neurocritical care that clearly improves outcome despite an incompletely understood mechanism.

The nurse calls again.

The MAP is 65 mmHg.

The next nimodipine dose is due.

The evidence has gaps. The grey zone remains.

Operating within these spaces is the essence of neurocritical care.

For now, the strongest signal we have is still the one first described in the British Aneurysm Nimodipine Trial more than three decades ago.

Continue the nimodipine.

Protect cerebral perfusion.

Follow the physiology in front of you.

Further Reading

• Pickard JD, Murray GD, Illingworth R, et al. Effect of Oral Nimodipine on Cerebral Infarction and Outcome After Subarachnoid Haemorrhage: British Aneurysm Nimodipine Trial. BMJ. 1989;298(6674):636–642.

• Macdonald RL, Kassell NF, Mayer S, et al. Clazosentan to Overcome Neurological Ischaemia and Infarction Occurring After Subarachnoid Haemorrhage (CONSCIOUS-1). Stroke. 2008;39:3015–3021.

• Pala A, Hecht N, Vajkoczy P, et al. The Influence of Nimodipine and Vasopressors on Outcome in Patients with Delayed Cerebral Ischaemia after Spontaneous Subarachnoid Haemorrhage. J Neurosurg. 2020;132(4):1096–1104.

• Cho S, Bales J, Tran T K, et al. Effects of 14 Versus 21 Days of Nimodipine Therapy on Neurological Outcomes in Aneurysmal Subarachnoid Hemorrhage Patients. Ann Pharmacother. 2016;50:718–724.

• Sokolowski JD, Chen CJ, Soldozy S, et al. Nimodipine After Aneurysmal Subarachnoid Hemorrhage: Fourteen-Day Course for Patients That Meet Criteria for Early Hospital Discharge. Clin Neurol Neurosurg. 2021;200:106299.

• Thilak S, Brown P, Whitehouse T, et al. Diagnosis and Management of Subarachnoid Haemorrhage. Nat Commun. 2024;15:1850.

• Llompart-Pou JA, Pérez-Bárcena J, Godoy DA. Nimodipine in Aneurysmal Subarachnoid Hemorrhage: Are Old Data Enough to Justify Its Current Treatment Regimen? Neurocrit Care. 2025;42:334–340.

• Hoh BL, et al. 2023 Guideline for the Management of Patients With Aneurysmal Subarachnoid Haemorrhage. Stroke. 2023;54(7)–e370.

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In the ICU, we see death closely. It is not like an accident scene where someone dies on impact. When those trauma patients do arrive in the ER, we watch them struggle in a chaotic burst.

The death I am referring to belongs to the patients who linger in our ICUs for long periods, the ones we slowly watch fade away. Here, there is a story. We witness the transition. Organ by organ, system by system, they begin to fail.

When the BP falls, that is feedback. Not a verdict.

It tells us to act. We adjust, intervene, and fight. Many times, we succeed.

But I am thinking about the times when we do everything and they still slip through. That is when they enter the gray zone.

I often wonder what that space feels like.

Do they realize what is happening? Are they yearning to come back to this side, or praying for the end to come faster? Are they hoping for one final chance to say something they never said? Do they still long for simple things, the taste of food, the smell of home, the feeling of being themselves again?

And in that gray zone, are we sometimes making them stay longer through our attempt to pull them back?

Then there is the family. They have never seen the person they love this way.

The reality of working in the ICU is that death slowly becomes normal to us. We detach quickly. Or maybe we are never attached enough to detach in the first place. Perhaps we have to become this way to keep going.

But during my training days, a friend once told me something that stayed with me.

“After they fade, stand at the end of the bed for a few seconds and ask yourself: could you have done anything better?”

That is reflection.

In my last post, we looked at how treating acute stroke requires us to look past rigid timelines. The clock is a suggestion. The physiology is the mandate.

But honoring that mandate becomes difficult when the physiology hides behind a word we use every day.

Stable.

You walk into the unit for morning rounds. The night doctor hands over the patient in bed four with a familiar phrase.

“Quiet night. He is stable.”

You stand at the bedside. The monitor agrees. Heart rate 85. Blood pressure acceptable. Saturations fine. Everything looks reasonable.

But you look at the patient and immediately feel uncomfortable.

The patient is not crashing. There are no alarms. Yet something does not look right. Maybe it is the way they are breathing, just a little faster and shallower than yesterday. Maybe they look more tired. Or maybe it is what happened ten minutes ago. The nurse turned them to change the sheets, their heart rate climbed to 135, and it took twenty minutes to settle. Yesterday it settled in two.

The numbers are fine, but the patient looks fragile.

You know what this means. The body is working hard just to keep those numbers where they are.

You step outside and speak to the family.

“His numbers look acceptable right now. But I feel he is still on the edge. He does not have much reserve. We need to watch him closely.”

Back at the bedside, you leave instructions for whoever comes next.

“Do not lay this patient flat.”

“Be careful while suctioning.”

“Cluster care and let him rest.”

These are not preferences. Every item on that list is a place where this patient could lose ground he cannot afford to lose. Laying him flat shifts fluid toward the lungs. Suctioning triggers coughing and pushes the heart rate up. Repeated bedside tasks can sometimes flip the balance.

A healthy person absorbs all of this without consequence. This patient cannot.

So you write it down, make sure the team sees it, and hope it is enough.

Later that afternoon, he deteriorates. Someone says the sentence we hear all the time in the ICU.

“He was stable just an hour ago.”

Sometimes deterioration really is sudden. A pulmonary embolism or a major bleed can change everything within minutes. But most ICU deterioration is not sudden at all. We often see it long before the alarms start.

Over time, you become sensitive to these patients. You learn to read what the monitor does not capture. The monitor is a lagging indicator. It tells you what physiology looks like at that moment, but not how much work the body is doing to maintain it.

A heart rate of 85 looks reassuring on the screen. What the monitor cannot tell you is how hard the body is working to keep it there.

That is what the twenty minutes told you. Not that the heart rate was high. That the body was struggling to bring it back down.

Critical illness usually does not fail abruptly. It compensates quietly. For hours or sometimes days, the body bends without visibly breaking. The patient maintains the appearance of stability by using whatever reserve is left.

Eventually, there is nothing left to compensate with.

The collapse looks sudden.

The physiology rarely is.

The Era of Chronological Rigidness (1995–2008)

For those of us in neuro-critical care during the late 90s, the management of acute ischemic stroke (AIS) was defined by a binary helplessness. Prior to 1995, we were limited to supportive care and watching the natural history of infarct completion.

The 1995 NINDS trial changed the field permanently. Proving that IV alteplase within three hours yielded an NNT of ~8, it birthed the “time is brain” paradigm. But it was a double-edged sword: it gave us a tool, but it bound our hands once the clock hit 181 minutes.

The first crack in this wall was ECASS-III (2008), extending the window to 4.5 hours. However, the NNT jumped to 14. This was our first quantitative signal that treating later based purely on a clock meant treating less precisely. We were still treating a population average; the clock had been loosened, but not broken.

2015: The Plumbing Revolution

Between 2008 and 2015, we faced the “failed years” of IMS-III and SYNTHESIS. We were sending catheters into vessels without mandatory CTA confirmation and using first-generation retrievers. We were not failing because the concept was wrong; we were failing because our selection was blind.

The revolution began in January 2015 with MR CLEAN — mandatory CTA confirmation of LVO and stent-retrievers — yielding an NNT of 7. Within months, four more trials confirmed the signal, each adding a layer of physiological precision:

• ESCAPE extended the window to 12 hours using CTA-based collateral assessment (NNT ~4).

• EXTEND-IA and SWIFT PRIME added CT perfusion mismatch selection and drove the NNT down to a staggering 3.

• REVASCAT confirmed the result in a European population using ASPECTS and CTA alone.

The HERMES meta-analysis subsequently pooled all five trials and confirmed the result unambiguously: a Class 1 recommendation for Mechanical Thrombectomy (MT) in proximal anterior circulation LVO within 6–12 hours. Crucially, benefit was demonstrated across different selection methods — proving that tissue viability, not the selection tool, was the common denominator.

The Tissue Revolution: Lysis Beyond 4.5 Hours

The most aggressive lysis extensions — WAKE-UP (2018) and EXTEND (2019) — actually followed the initial mechanical success. These trials applied “Thrombectomy Logic” back to the drug.

By using MRI (DWI-FLAIR mismatch) or CT Perfusion (core-penumbra mismatch), we proved the 9-hour window was a reality for slow progressors. IV thrombolysis is now a Class 2a recommendation up to 9 hours when imaging confirms salvageable tissue. This completed the shift from “Time of Onset” to “Imaging Mismatch.”

The “Slow Progressor” and the 24-Hour Frontier

The physiological basis for these windows is the “Slow Progressor” — the patient whose leptomeningeal collaterals sustain the penumbra and markedly slow infarct growth kinetics compared with typical infarct progression. DAWN and DEFUSE-3 (2018) formalised this: using clinical-imaging mismatch (DAWN) and perfusion-core mismatch (DEFUSE-3), they achieved an NNT of 2–3 up to 24 hours — some of the most potent treatment effects recorded in modern clinical medicine.

The final dogma to fall was the Large Core (ASPECTS 3–5). Historically, we feared reperfusion injury in these patients — and the reasoning felt physiologically sound. Reperfuse dead brain and you get haemorrhage, oedema, herniation. The malignant MCA syndrome, arriving on schedule.

What SELECT2, ANGEL-ASPECT, TENSION, and LASTE collectively demonstrated is that NCCT-defined “large core” physiology is more heterogeneous than previously assumed. While much of the hypodense region represents established infarction, surrounding peri-core tissue may remain physiologically vulnerable, oedematous, and potentially salvageable with reperfusion.

The numbers are specific enough to be worth stating in full. SELECT2 (ASPECTS 3–5 or core ≥50 mL, up to 24 hours) showed mRS 0–2 at 90 days in 20% with MT versus 7% with medical management. ANGEL-ASPECT (core 70–100 mL, up to 24 hours) pushed further — 30% versus 11.6%. TENSION (ASPECTS 3–5, within 12 hours) demonstrated a significant functional mRS shift with an adjusted odds ratio of 2.58.

LASTE took the most aggressive position: ASPECTS 0–5, strictly within 6.5 hours — a hyper-acute large core population — and showed 1-year mRS 0–2 of 31.3% versus 19.3%. In the LASTE subgroup with the most severe imaging burden, ASPECTS 0–2, the 3-month mRS 0–3 rate was 31.4% with EVT versus 8.5% with medical management alone. That is the patient most of us were not considering for consent, let alone treatment.

The NNT across these trials is approximately 8 — remarkable for a population excluded from every prior guideline. More importantly, reperfusion prevents the malignant haemodynamic cascade — progressive oedema, midline shift, the hemicraniectomy tray — that defines the untreated natural history. In the neuro-ICU, that distinction is clinically urgent. The conversation we now need to have is not whether to treat these patients, but how to counsel families honestly about what “better outcome” means in the context of a large baseline infarct. That conversation, the guidelines do not yet teach us to have.

The 2026 Bedside Reality: The Actionable Shifts

The 2026 AHA/ASA Guidelines have codified these shifts into a high-velocity, individualised approach.

The TNK Bolus (Class 1)

Tenecteplase (0.25 mg/kg, max 25 mg) replaces the 60-minute alteplase infusion. A 10-second “push and go” that simplifies drip-and-ship logistics and accelerates transition to the angio suite. One ongoing procedural concern is whether rapid thrombus fragmentation with TNK may occasionally contribute to distal embolisation before thrombectomy, potentially complicating downstream retrieval in some LVOs. Current evidence still strongly supports TNK, particularly given its favourable early recanalisation profile, but this remains an area of active procedural discussion among stroke interventionists.

Large Core MT (Class 1, Level A)

Reperfusion for ASPECTS 3–5, core volumes up to 150 mL, within 6–24 hours — now the highest evidence grade. Three years ago these patients were often managed conservatively. In 2026, consideration of MT for appropriately selected large-core patients is increasingly expected within comprehensive stroke systems.

Disabling Deficit over NIHSS

We no longer treat numbers. A dense aphasia with an NIHSS of 2 is functionally catastrophic for a working professional. A paralysed dominant hand scores 1. The standard is thrombolysis for any disabling deficit within 4.5 hours regardless of the absolute score. Conversely, for genuinely non-disabling strokes — isolated sensory syndrome — thrombolysis is not recommended; dual antiplatelet therapy is preferred. If it does not disable them, do not lyse them.

Permissive BP post-EVT

The reflex to hammer SBP below 140 mmHg after successful recanalisation has been overturned. ENCHANTED2/MT and OPTIMAL-BP showed that intensive lowering blunts autoregulatory responses and reduces collateral perfusion to recovering penumbral tissue. The 2026 target is <180/105 mmHg for the first 24 hours. Treat this as directional — the optimal range remains under active study — but the instinct to aggressively lower BP post-thrombectomy needs to be unlearned.

Metabolic Targets

Blood glucose has been relaxed from 80–130 to 140–180 mg/dL — the ischaemic brain is exquisitely sensitive to hypoglycaemia, and tight control in the neuro-ICU costs more than it saves. Temperature: treat hyperthermia aggressively, target <38°C. Neither is new science, but both continue to be under-prioritised on overnight shifts.

Basilar Artery Occlusion

Contemporary guidelines now strongly support MT for appropriately selected patients with significant posterior circulation stroke syndromes, including many presenting within 24 hours. Posterior circulation stroke — long considered the unresolved frontier — is finally entering the reperfusion era with increasing confidence.

Mobile Stroke Units: Class 1

CT-equipped ambulances with on-scene thrombolysis capability now carry the highest guideline endorsement. For those designing regional stroke networks, this is a planning mandate, not an aspiration.

Paediatric Stroke — first-ever dedicated guidance

IV alteplase within 4.5 hours for children aged 28 days to 18 years with disabling deficits. MT for LVO in children ≥6 years within 6 hours, potentially to 24 hours with salvageable imaging. An entire patient population that previously had no evidence-based roadmap now does.

What the Revolution Has Not Reached

Intellectual honesty demands acknowledging the gaps.

Intracerebral haemorrhage remains the orphan. Despite MISTIE-III, ENRICH, and others, ICH still lacks a SELECT2-equivalent — a definitive trial demonstrating functional benefit from active intervention. We are still largely watching and managing complications.

Neuroprotection has failed so consistently — SAINT-I and II, NXY-059, FAST-MAG, glutamate antagonists of every variety — that it has become something of a dark joke in the field. The ischaemic cascade remains pharmacologically untouchable beyond reperfusion itself. The graveyard of neuroprotective agents is enormous.

Distal medium vessel occlusion is the active and unresolved frontier. DISTAL and ESCAPE-MeVO both failed to show MT benefit over medical management — and ESCAPE-MeVO suggested potential harm and higher mortality with stent retrievers in these fragile, thin-walled vessels. For now, the evidence does not support routinely chasing distal clots.

CritiTAR Reflection

This is the numerical signature of a field learning to select for physiology rather than chronology. Notice that the arc does not only descend. The NNT of 14 in ECASS-III’s extended window — buried in what was otherwise a positive trial — was the first quantitative signal that time and tissue were different variables and we had been conflating them for a decade. Every subsequent advance was, in some sense, an elaboration of that single observation.

In 2026, the management of stroke has moved from the emergency room stopwatch to the neuro-intensivist’s workstation. The brain does not die on a schedule. It dies when its collaterals fail, when its autoregulation exhausts, when the oedema crosses the midline. Our job is to understand which of those processes is dominant in the patient in front of us — not to check the time on the wall.

Primary trials: NINDS (1995) · PROACT II (1999) · ECASS-III (2008) · SYNTHESIS / MR RESCUE / IMS-III (2013) · MR CLEAN / ESCAPE / EXTEND-IA / SWIFT PRIME / REVASCAT (2015) · HERMES (2016) · DAWN / DEFUSE-3 / WAKE-UP (2018) · EXTEND (2019) · ENCHANTED2/MT (2022) · AcT / TRACE-2 (2022–23) · SELECT2 / ANGEL-ASPECT / TENSION (2023) · LASTE / DISTAL / ESCAPE-MeVO / OPTIMAL-BP (2023–24)

Guideline: 2026 AHA/ASA Guideline for the Early Management of Patients With Acute Ischemic Stroke. Stroke, 2026.

In the ICU, we depend on real-time physiology. We watch the heart beat on a monitor second by second. We measure lung mechanics breath by breath. We track hourly urine output with relentless precision.

But the brain remains medicine’s greatest black box. It is the only organ sealed inside a rigid vault of bone—an organ we often cannot truly “see” unless we drill through the skull itself.

Between the moment of injury and the decision to place an invasive monitor lies a dangerous territory: The Intracranial Grey Zone.

This is the window where secondary brain injury is already evolving, but traditional triggers for intervention may not yet appear. By the time a pupil dilates, motor posturing develops, or a Cushing reflex emerges, we are often witnessing the late-stage consequences of a process that began hours earlier.

The question is no longer whether intracranial physiology matters; it is whether we are seeing it early enough.

Beyond the Bolt: The Emerging Role of nICP

The April 2026 narrative review by Emanuela Picetti and colleagues reframes non-invasive intracranial pressure estimation (nICP) not as a weaker substitute for the bolt, but as a critical screening framework.

Its value lies in:

1. Screening and Triage: Identifying patients drifting toward intracranial hypertension (IH) before irreversible injury declares itself clinically.

2. The “Safety Interim”: Providing physiological guidance when invasive monitoring is delayed, unavailable, or unsafe—such as in severe coagulopathy or resource-limited environments.

The goal is to illuminate the blind interval before the bolt.

Peering Through Different Physiological Windows

Modern nICP methods attempt to interrogate the brain indirectly through multiple physiological “windows.” Each captures a different fragment of the intracranial story.

The Vascular Window — TCD/TCCD

Using Transcranial Doppler, we observe cerebral blood flow dynamics in real time. As intracranial compliance worsens and ICP rises, diastolic flow falls while waveform pulsatility increases.

• Clinical Signal: A Pulsatility Index (PI) > 1.5 —when not explained by hypotension or hypocapnia—should raise concern for elevated ICP.

• Reality Check: Accuracy remains limited with 95% limits of agreement (LoA) of approximately +/- 7–15 mmHg. It is a tool for trend analysis and identifying physiological extremes rather than exact pressure quantification.

The Anatomical Window — ONSD

The optic nerve sheath (ONS) communicates directly with the intracranial subarachnoid space; as pressure rises, the sheath expands.

• Clinical Signal: An optic nerve sheath diameter (ONSD) > 5.9 mm demonstrates good diagnostic performance for IH (83% sensitivity and specificity).

• Reality Check: Technique is everything. Without standardized acquisition—such as the CLOSED protocol—technical variability masquerades as physiology. We must also account for a potential 22% discrepancy between measuring the internal subarachnoid space (ONSDint) versus the external dural sheath (ONSDext).

The Brainstem Window — Automated Pupillometry

This transforms the pupillary exam from subjective observation into quantified neurophysiology.

• Clinical Signal: A Neurologic Pupil Index (NPi) < 3 may identify evolving midbrain compression even before overt clinical herniation.

• Reality Check: NPi alone is unreliable for exact ICP estimation and must be used in conjunction with other nICP methods and the clinical picture.

The Micrometric Window — Skull Micro-Deformation

Even the adult skull undergoes subtle micrometric expansion with each cardiac cycle.

• Clinical Signal: When the P2 waveform exceeds P1, intracranial compliance may already be failing—even before dramatic ICP elevation occurs.

• Compliance Staging: A P2/P1 ratio > 1.4 with a time-to-peak (TTP) > 0.3 strongly indicates Stage 3 (depleted compliance).

• Reality Check: This is compliance physiology, and compliance can fail long before pressure catastrophically rises.

The Radiographic Mirror: CT and MRI

If nICP is our continuous physiological feed, neuroimaging is our intermittent flashlight. CT and MRI identify structural causes—midline shift, basal cistern effacement, hydrocephalus, or mass lesions.

However, imaging remains a static snapshot. A CT scan cannot see the minutes and hours of physiological drift between trips to the scanner. As Picetti et al. suggest, nICP acts as a bridge: a rising nICP trend determines the urgency of the next scan, while imaging provides the anatomical “calibration” for our bedside findings.

Triangulation: Seeing Ahead of the Curve

No single nICP modality is reliable enough in isolation. The 2025 B-ICONIC framework proposes Multimodal Integration: combining at least two different nICP methods with clinical and radiological data.

A rising ONSD trend combined with worsening TCD pulsatility and an abnormal P2/P1 relationship paints a far more meaningful picture than any isolated number. We are watching the brain exhaust its compensatory reserve in real time.

The Ghost of BEST-TRIP

Neurocritical care has taught us to be cautious about seductive physiology. The ghost of the BEST-TRIP Trial lingers over every ICP discussion. That trial proved that treating a “number” alone does not necessarily improve outcomes compared to clinical and radiological management.

This raises the ultimate questions for the nICP era:

• Are we intervening at the right moment? Earlier detection of physiological deterioration is now possible, but does it prevent secondary injury or simply recognize an inevitable decline sooner?

• Does better monitoring change biology? High-resolution monitoring can improve our understanding without necessarily improving survival.

• Should we be measuring reserve instead of pressure? Perhaps the future is not absolute ICP values, but the dynamic loss of intracranial compliance—the moment the brain transitions from compensation to collapse.

We have spent decades being blind to intracranial physiology. Now we finally have tools that allow us to see through the bone.

The unanswered question is whether earlier sight will truly let us alter the trajectory of injury—or whether we are simply learning to watch the brain fail in higher resolution.

CritiTAR Reflection:

Neurocritical care may not be about finding the perfect ICP number—but recognizing the moment the brain runs out of reserve.

Sources

• Picetti, E. et al. (2026). Non-invasive intracranial pressure estimation in the intensive care unit: narrative review. Intensive Care Medicine.

• Robba, C. et al. (2025). The Brussels consensus for non-invasive ICP monitoring (B-ICONIC). Intensive Care Medicine.

• BEST-TRIP Trial. NEJM (2012).

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That line shows up in every ultrasound workshop. It’s become a clinical ritual. And yet, in the ICU, the behavior hasn’t changed.

• A 1.2 cm IVC? “He’s dry.”

• A 2.5 cm IVC? “He’s full.”

The problem isn’t that the IVC is imperfect. The problem is deeper: We are using a pressure signal to make a volume decision—inside a system defined by competing pressures.

1. The Pressure Illusion: When RAP Stops Meaning Anything

The IVC is not a tank. It is a surrogate for Right Atrial Pressure (RAP). But RAP only has meaning if the surrounding pressures are stable. In the ICU, they rarely are.

The High-Effort Trap

A patient in respiratory distress generates large negative intrathoracic pressures. The IVC collapses, RAP appears low, and you feel justified giving fluids.

But what are you actually seeing? You are not seeing volume depletion—you are seeing pressure distortion from respiratory effort. You give fluid. Stroke volume may increase marginally. But the cost?

• Increased venous return into a struggling RV

• Worsening pulmonary congestion

• Amplified work of breathing

You treated the number—and amplified the physiology you should have fixed.

The PEEP Shield

Conversely, high PEEP elevates intrathoracic pressure. The IVC appears plethoric. RAP looks high. But:

• Venous return may be impaired

• Cardiac output may be low

A “full” IVC can coexist with inadequate forward flow.

The Core Insight: IVC diameter is not volume. It is pressure under conditions. Change the conditions, and the number lies.

2. The Missing Half: Upstream Signals vs. Downstream Consequences

Most POCUS frameworks focus upstream: “Can I give fluid?” But the ICU reality is different: The real danger of fluid is not what it does to the heart—it’s what it does to the organs.

Looking beyond the IVC into venous flow patterns shifts the question: Not “Can I fill?” but “What happens if I do?”

This is a better lens—but not a complete one. Venous assessment has limits:

• Waveforms are influenced by rhythm and valvular disease

• Patterns vary in RV dysfunction

• Renal Doppler is technically demanding

• Intra-abdominal pressure can confound interpretation

And in real life, you will not always have clean or complete downstream data. You are not removing uncertainty—you are reducing blind spots.

Where This Actually Matters

• Large IVC (2.5 cm), minimal congestion: Downstream still compliant → Volume may be tolerated.

• Moderately dilated IVC (~2.1 cm), severe venous congestion: The organ is already under back-pressure → That bolus is not support—it is injury.

• “Normal” IVC, abnormal venous flow: The most dangerous scenario → Hidden congestion despite reassuring upstream signals.

IVC is a warning light. Downstream signals are evidence of consequence.

3. The Conflict Zone: When Physiology Disagrees

This is where protocol ends and Point of Care Thinking begins.

• Scenario 1: Flow improves, but congestion is severe Stroke volume increases with a dynamic test. Yet venous congestion is already significant. You are trading a linear gain in cardiac output for a nonlinear rise in venous pressure.

• Scenario 2: “Empty” IVC, fragile lungs Upstream suggests hypovolemia. Lung signals say otherwise. The lung is telling you: “I will fail before your pressure improves.”

• Scenario 3: “Full” IVC, poor flow High filling pressures. Low output. Volume is not the limiting factor here—flow is, and it is being choked by pressure.

The mistake isn’t choosing the wrong variable. It’s believing any single variable can decide for you.

4. The Functional Shift: Stress-Testing the System

Static numbers are seductive because they are easy. But physiology is dynamic. The real question is not: “What does the IVC look like?” It is: “How does the system respond—and what does that response cost?”

To find the answer, we look at three stress axes anchored by one clinical reality:

1. Pump Stress: Can flow increase? (Dynamic tests like leg raises).

2. Backward Pressure: What is the cost of giving fluid? (Venous congestion patterns).

3. Lung Stress: Where will fluid fail first? (Early pulmonary interstitial signals).

4. Perfusion Outcome (The Anchor): Is any of this actually improving tissue perfusion? (Capillary Refill Time).

5. The Missing Question: Did It Work?

We spend enormous effort predicting response. But the patient doesn’t care about prediction. The only question that matters is: Did perfusion improve?

Capillary refill time forces that question. It is not a predictor—it is a real-time consequence.

• Flow increases, but CRT is normal: You improved a number, not the patient.

• Flow increases, CRT improves, congestion worsens: You are watching the trade-off unfold in real time.

• IVC “full”, CRT prolonged: This is not a fluid problem—think flow, not volume.

• CRT improves before BP changes: Perfusion has shifted before macrocirculation catches up.

The Caveat: CRT is not perfect. It is influenced by temperature, vasopressors, and peripheral tone. Its value lies not in a single reading—but in its response to intervention.

The Takeaway

The IVC is not wrong. It is simply incomplete. The real mistake is not over trusting the IVC—it’s trusting any single variable in a system defined by interacting pressures.

Every fluid bolus is a wager: a potential gain in forward flow against a potential cost in venous congestion. If you are only looking at the IVC, you are making that decision without seeing the cost—and without knowing if it helped.

Even after integrating all signals, physiology rarely gives you a clean answer. You are not eliminating uncertainty—you are choosing which risk to accept.

The CritiTAR Bottom Line:

• Don’t ask: “Is the IVC small?” Ask: “What pressures created this number?”

• Don’t ask: “Can I give fluid?” Ask: “What will this do downstream?”

• Don’t ask: “Did stroke volume increase?” Ask: “Did perfusion improve?”

Flow without perfusion is meaningless. Pressure without context is dangerous. Numbers without consequence are noise.

Stop treating the vessel. Start treating the flow. In the ICU, physiology rarely gives you the right answer—only better questions.

Your job is not to be certain. It is to understand what each decision will cost.