ABPN Neurocritical Care common mistakes
ABPN Neurocritical Care · Understand the traps and how to avoid them.
Treating the cerebral perfusion pressure target as a fixed number (e.g., always >60 mmHg) instead of individualizing it to the patient's autoregulatory status and intracranial pressure trend, and failing to recalculate CPP when the arterial line transducer is zeroed at the wrong level.
CPP equals mean arterial pressure minus ICP, but candidates memorize a threshold and forget that the MAP and ICP components must both be verified (transducer at the tragus/phlebostatic axis, ICP waveform quality) before acting on the number. Exam items often give conflicting MAP/ICP values to test whether the candidate computes rather than recalls.
What to do instead
On every CPP item, explicitly compute MAP minus ICP, state the assumed zeroing level, and check that ICP is a valid waveform-derived value. Practice items that vary MAP and ICP independently so the arithmetic becomes automatic.
Selecting IV thrombolysis or endovascular therapy based on the time window alone without first confirming the last-known-well time, the exclusion criteria (recent surgery, anticoagulation, platelet count, glucose), and the imaging findings (hemorrhage exclusion, large-vessel occlusion on vessel imaging).
Candidates anchor on 'within 4.5 hours' or 'within 24 hours with mismatch' and skip the checklist. The exam deliberately embeds one disqualifying factor (e.g., INR 2.1, glucose 38 mg/dL, hypodensity >1/3 MCA territory) in an otherwise eligible vignette.
What to do instead
Use a fixed pre-thrombolysis checklist for every item: last-known-well, absolute contraindications, labs (glucose, platelets, INR), and noncontrast CT findings. If any single exclusion is present, stop and select the alternative management (e.g., endovascular alone, or no reperfusion).
Managing elevated ICP with a single intervention and declaring success, rather than escalating through a tiered pathway (head of bed, sedation, osmotic therapy, CSF diversion, temperature control, then decompression) and reassessing after each step.
Vignettes present a high ICP and candidates jump to the most dramatic intervention (decompressive craniectomy, barbiturate coma) without first excluding reversible causes (hypoventilation, seizures, fever, obstruction of an EVD) and without confirming that first-line measures were optimized.
What to do instead
For each ICP item, list reversible contributors first (PaCO2, seizure, fever, EVD patency, sedation depth), then apply the least invasive effective step and state the reassessment interval. Only escalate to decompression or barbiturates when lower tiers have failed and hemodynamics permit.
Reading a raw EEG as 'seizure' or 'no seizure' without applying the Salzburg criteria (epileptiform discharges >2.5 Hz, or rhythmic activity with spatiotemporal evolution, or clinical improvement with a benzodiazepine) and without distinguishing ictal from interictal or periodic patterns.
Candidates see rhythmic or periodic activity and label it status epilepticus, or conversely dismiss a subtle pattern because there is no convulsion. Nonconvulsive status and periodic discharges are the highest-yield EEG distinctions, and the exam tests the diagnostic criteria rather than pattern recognition alone.
What to do instead
For every EEG item, work through the three Salzburg branches explicitly and state which branch (if any) is met. Practice distinguishing lateralized periodic discharges, generalized periodic discharges, and triphasic waves from electrographic seizures using the frequency and evolution criteria.
Attributing new weakness in an ICU patient to the primary neurologic illness (stroke, TBI) instead of working up critical illness polyneuropathy/myopathy or a neuromuscular junction disorder, and failing to check for a spinal cord lesion when the weakness is symmetric or ascending.
The exam uses a distractor-rich vignette where the obvious diagnosis is the admission diagnosis, and the correct answer is a superimposed ICU-acquired weakness or Guillain-Barre. Candidates anchor on the first diagnosis and do not re-examine the temporal pattern (new weakness after days of sepsis, steroids, or neuromuscular blockade).
What to do instead
When weakness appears or worsens during an ICU stay, systematically consider: new CNS event, spinal cord compression, critical illness polyneuropathy/myopathy (sepsis, steroids, paralytics), NMJ disorder, and electrolyte/endocrine causes. Order EMG/NCS and imaging accordingly, and check for respiratory involvement (NIF, vital capacity).
Clearing or declining to clear a cervical spine based only on a normal CT in an obtunded or intoxicated trauma patient, or missing that a post-operative neurosurgical patient with new deficits needs urgent imaging before any repositioning or extubation.
The exam tests the difference between clinical clearance (requires a reliable exam) and radiographic clearance (CT plus, in some protocols, MRI or dynamic flexion-extension). Candidates also forget that post-op deterioration is a surgical emergency until proven otherwise.
What to do instead
State explicitly whether the patient can be clinically cleared; if not, describe the imaging-based clearance pathway and immobilization continuation. For post-op patients with new deficits, order immediate CT (and CTA if vascular injury is possible) and notify the surgeon before any airway or positioning change.
Managing sodium and glucose in the neuro-ICU with general ICU targets (e.g., correcting hyponatremia rapidly, targeting tight glycemic control) without accounting for cerebral edema risk, osmotic demyelination, or the different sodium goals for SAH, TBI, and post-op neurosurgical patients.
Candidates apply general critical care rules and miss the neuro-specific exceptions: slow correction of chronic hyponatremia, avoidance of hypotonic fluids in elevated ICP, and the fact that tight glycemic control increases hypoglycemia risk in brain-injured patients. The exam embeds a sodium or glucose value that changes the answer.
What to do instead
For every electrolyte/glucose item, state the neuro-specific target and the rate limit (e.g., sodium correction <8-10 mEq/L per 24 h in chronic hyponatremia; avoid hypotonic maintenance in raised ICP; glucose target roughly 140-180 mg/dL with hypoglycemia avoidance). Recheck the value after each intervention.
Declaring brain death without completing the full prerequisite set: excluding confounding factors (hypothermia, sedatives, neuromuscular blockade, severe metabolic derangement), confirming the cause is irreversible, and documenting apnea testing with an adequate PaCO2 rise and hemodynamic stability.
Candidates focus on the clinical exam (no brainstem reflexes, coma, apnea) and skip the prerequisites and the interpretation of the apnea test. Exam items frequently include a confounder (core temp 33 C, vecuronium on board, PaCO2 rise insufficient) that invalidates the determination.
What to do instead
Use a brain-death checklist: cause established and irreversible, confounders excluded (temperature, drugs, electrolytes, hemodynamics), then exam, then apnea test with documented pre/post PaCO2 and stability. If any prerequisite fails, state that ancillary testing (e.g., cerebral blood flow study) or deferral is required.
Framing prognostication and withdrawal-of-care discussions around a single early predictor (e.g., a low GCS or a bad CT) instead of using a multimodal, time-dependent assessment and separating prognostic uncertainty from a decision to withdraw.
Candidates want a definitive answer and pick the intervention or statement that implies certainty. The exam tests awareness of self-fulfilling prophecy, the need for serial examination, and the ethical requirement to involve surrogates with shared decision-making rather than unilateral withdrawal.
What to do instead
For prognostication items, name at least two modalities (clinical exam over time, electrophysiology, imaging biomarkers) and state the uncertainty explicitly. For end-of-life items, select the answer that involves the surrogate, documents goals of care, and avoids conflating a poor prognosis with a directive to withdraw.
Missing the toxidrome or antidote for a neuro-ICU poisoning (e.g., failing to give sodium bicarbonate for a wide-complex QRS from tricyclics, or giving flumazenil to a mixed overdose) and ignoring that many ICU drugs themselves cause the neurologic deterioration (e.g., cefepime neurotoxicity, metronidazole encephalopathy, opioid-induced sedation).
Candidates focus on the primary neurologic diagnosis and do not review the medication list for iatrogenic causes, and they memorize antidotes without the contraindications. The exam uses a patient who deteriorates after a new antibiotic or sedative as the correct answer.
What to do instead
On any unexplained encephalopathy or seizure in the ICU, review the medication list for neurotoxic agents (cephalosporins, carbapenems, metronidazole, fluoroquinolones, opioids, benzodiazepines) and consider drug levels. For toxidromes, pair each antidote with its indication and contraindication (e.g., bicarbonate for TCA QRS widening; avoid flumazenil in mixed overdose or seizure history).