Anesthesiology APPLIED Exam › Critical care, resuscitation and trauma

Brain death and the organ donor

Critical care, resuscitation and trauma·~4 min read· Physician-reviewed✓ Sourced · 3

Stem

A 24-year-old man, 78 kg, with a severe traumatic brain injury was declared dead by neurologic criteria this morning, and his family has consented to donation of heart, lungs, liver and kidneys. He arrives in the operating room for procurement on norepinephrine. Blood pressure is 84/48 mmHg, urine output is 450 mL/h, sodium is 156 mmol/L, and his temperature is 35.2 °C.

Question

What is your role, and how will you manage him in the operating room?

Ideal answer

HeadlineHe is legally dead; my job: every organ perfused and oxygenated until cross-clamp. I confirm declaration, time of death, consent.

MAP at least 65, fluid first,¹ as 450 mL/h dilute urine, nearly 6 mL/kg/h, and sodium 156 mean diabetes insipidus.
Vasopressin 0.01 units/min, titrated toward 0.06, treating hypotension and diabetes insipidus;¹ desmopressin 4 mcg then 2 mcg every 6 hours if urine stays above 4 mL/kg/h.¹
Hypotonic replacement toward sodium 135–155,¹ for his free-water loss; urine 0.5–3 mL/kg/h.¹
Lungs-first ventilation, 6–8 mL/kg predicted weight, PEEP at least 8,¹ to protect transplantable lungs.
Still unstable: levothyroxine, 100 mcg, then 50 mcg every 12 hours;¹ warm him, hemoglobin at or above 70 g/L, methylprednisolone if lung team asks.¹

Watch for: reflex hypertension and movement: relaxant, treat pressure.

Breaking down the answer

Confirm death before acting — neurologic criteria need a known catastrophic cause, exclusion of confounders such as temperature below 36 °C, MAP below 75, drugs and neuromuscular blockade, then coma, absent brainstem reflexes and a positive apnea test.²
Brain death destroys homeostasis — loss of vasomotor tone, diabetes insipidus, hypothermia and coagulopathy all threaten the grafts; naming them shows organization.
Vasopressin is dual-purpose — it restores tone and replaces antidiuretic hormone;¹ desmopressin adds antidiuretic effect without pressor effect.
Why lung protection — excess volume and large tidal volumes injure donor lungs; a lung-protective strategy keeps them transplantable.¹
Spinal reflexes are expected — movements attributable entirely to the spinal cord are compatible with brain death,² but surges with incision still harm organs.
Targets vary — procurement organizations publish their own order sets; I follow theirs, and agree heparin and clamp timing with the procurement teams.

Follow-up question

At skin incision his blood pressure jumps to 190/110, the heart rate rises to 135, and his right arm flexes. The scrub nurse is upset and asks whether he is really dead. What do you do?

Follow-up answer

HeadlineA spinal reflex response: the cord below the brainstem still responds to noxious stimulation, compatible with brain death.² I pause briefly and explain.

I tell the nurse calmly that this is expected, that qualified physicians made the declaration, and why it happens. I treat it because the surge harms the heart: deeper neuromuscular blockade and a vasodilator or volatile agent for the pressure. If I saw anything not spinal, such as a pupillary response or breathing effort, I would stop and call the declaring physician before continuing. I reassess pressure and rhythm and keep the team informed.

Pitfalls that cost points

Treating the donor as an anesthetic for consciousness instead of an organ-perfusion problem.
Calling spinal reflexes evidence against brain death.

Rapid-fire

Q: What apnea test result confirms brain death? A: No respiratory effort with PaCO2 of at least 60 mmHg, at least 20 above baseline, and a pH below 7.30.²

Q: When is an ancillary test used? A: When the exam or apnea test cannot be completed or is uncertain; it shows absent intracranial flow or electrocortical silence.²

Q: How long after cardiac arrest before evaluation? A: At least 24 hours after return of circulation in a typical policy based on the 2023 guideline.³

Q: What is the legal time of death? A: The time of the final gas meeting apnea criteria, or when the ancillary study is finalized.³

Q: When do you abort an apnea test? A: Systolic below 100, MAP below 75, saturation below 85% or arrhythmia.²

Numbers to know

Item	Value
Apnea test	PaCO2 ≥60 and ≥20 above baseline, pH <7.30²
Exam prerequisites	Temperature ≥36 °C, MAP ≥75²
Donor MAP	≥65 mmHg¹
Urine output	0.5–3 mL/kg/h¹
Sodium	135–155 mmol/L¹
Vasopressin	0.01 to 0.06 units/min¹
Ventilation	6–8 mL/kg PBW, PEEP ≥8¹

Sources

1.Guidelines for Organ Donor Management (NDD) · Horizon Health Network, New Brunswick, 2021 · horizonnb.caInstitutional donor-management order set; targets vary between organ procurement organizations.
2.Guidelines for Determining Brain Death/Death by Neurologic Criteria in Patients ≥37 Weeks Old · Merck Manual Professional (table of the 2023 AAN/AAP/CNS/SCCM guideline), 2023 · merckmanuals.comSummarizes Greer DM et al., Neurology 2023;101(24):1112-1132.
3.Brain Death Policy · University of Alabama at Birmingham, 2025 · residency.peds.uab.eduInstitutional policy incorporating the 2023 guideline; used for waiting periods and time of death.

Facts on this page were checked against these sources on Oct 15, 2026. Guidelines change; confirm doses against current institutional protocols.