SESSION TITLE: Critical Care Student/Resident Case Report Posters I
SESSION TYPE: Medical Student/Resident Case Report
PRESENTED ON: Tuesday, October 28, 2014 at 01:30 PM - 02:30 PM
INTRODUCTION: Brain death (BD) is well entrenched as a legal and medical definition of death. Determination of BD is based in irreversible cessation of all functions of the brain, including brain stem. Apnea test is the definitive test to confirm BD. In special circumstances where uncertainty exists about parts of neurological exam or when apnea test cannot be performed, ancillary tests are needed to confirm BD.
CASE PRESENTATION: 46 year-old male with hypertension, diabetes, chronic kidney disease was admitted after seizure. Exam revealed an obese, hypertensive patient, GCS scale of 3/15. CT head revealed large acute intraparenchymal hematoma with midline shift from left to right and uncal herniation. Emergent left sided craniotomy with evacuation of subdural hematoma was performed. GCS improved to 6 (E1V1M4) on post-operative day 3. Hospital course complicated with pneumonia and respiratory failure. Later he was noticed to be clinically BD. Apnea test could not be performed in the floor and a cerebral perfusion scan with AP and lateral views was consistent with BD. Organ donation and family informed. In next 12 hours, patient was noticed spontaneous eye opening with change in neurological status. Repeated perfusion scan again showed no cerebral perfusion. Family opted for hospice care.
DISCUSSION: Commonly accepted ancillary tests in adults are EEG, cerebral angiography, radionuclide cerebral blood flow, TCD, CTA, and MRI/MRA. Cerebral nuclear scans are rarely associated with false positives and false negatives. False-positive occurs when nuclear scan reveal no perfusion, confirming BD but clinical exam is not consistent with BD. In a study of 229 scans in 219 patients, sensitivity of radionucleotide angiography was 98.5%; five patients were not clinically BD but had no flow. Explanation for presence of blood flow in radionucleotide angiography in clinically BD patients are test done closer( < 6 hours) after the neurologic event, problems in evaluating perfusion of the brain stem and differences between blood flow and function as indicators of irreversible loss of function of the brain. Some authors have suggested that a lack of lateral view could result in misinterpretation of BD. In our patient a second scan was done that revealed similar findings and we had both AP and lateral views discounting these as a possibility. We speculate that the false-positive scan was due to unidentifiable brain stem flow in radionucleotide scan.
CONCLUSIONS: Intensivists should be aware of false-positive radionucleotide scan in 2.5 % of cases that are clinically brain dead. Caution should be used during terminal disconnect.
Reference #1: Flowers WM Jr, Patel BR. Radionuclide angiography as a confirmatory test for brain death: a review of 229 studies in 219 patients. South Med J. 1997 Nov;90(11):1091-6.
DISCLOSURE: The following authors have nothing to disclose: Sara Qasim Bughio, Gilda Diaz-Fuentes, Sindhaghatta Venkatram
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