Cardiac transplantation as therapy for heart failure

The demonstration of absent blood flow to the brain is often used as a confirmatory test of brain death. Traditionally, cerebral angiography and dynamic radionuclide brain scanning have been used for this purpose. Recently, xenon CT cerebral blood flow techniques have been developed and applied to a wide variety of clinical problems, including the confirmation of brain death. We report our experience with xenon CT studies performed over a 7-year period (1983-1989) in 30 patients with brain injuries. These patients met clinical criteria for brain death within 24 hr of the study. Twenty patients had average global flow values of less than 5 ml/100 ml/min. Seven patients demonstrated mixed flow patterns, whereby large areas of brain showed flow values of less than 5 ml/100 ml/min and residual pockets of flow greater than 5 ml/100/ml/min. Globally symmetric normal to hyperemic flows were seen in three patients. Our study suggests that the demonstration of average global flows of less than 5/ml/100 ml/min is confirmatory of brain death. Demonstration of persistent flow to the entire brain or regions of the brain is not diagnostic of brain death but also does not exclude such an outcome in patients with severe brain injuries. Xenon-derived flow information may be clinically useful in determining the patient's prognosis and in counseling the patient's family.

http://www.ajnr.org/content/ajnr/12/1/97.full.pdf

The role of xenon CT measurements of cerebral blood flow in the clinical determination of brain death.

Brain death is defined as the cessation of cerebral and brainstem function. A 12-year-old boy presented with alleged history of snake bite. He was brain dead with Glasgow Coma Score of 3 and absent corneal reflexes. However, it was only neuroparalytic effect of the venom, which improved in due course of time with antivenoms. This case highlights the occurrence of both internal and external ophthalmoplegia, which would mimic brain death in many ways, thus prompting an intensivist to consider withdrawing ventilatory support, which would be disastrous.

Brain death—think twice before labeling a patient

Brain death is defined as the cessation of cerebral and brainstem function. It is a clinical diagnosis made on the results of a series of brainstem reflex testing, in the absence of endogenous or exogenous poisons, toxins and hypothermia confounding the clinical picture. It is known that certain chemical agents in snake toxin can alter the neuronal function mimicking brainstem death. In such situations, an objective method of demonstrating brainstem death becomes essential. The demonstration of lack of cerebral perfusion is the diagnostic criterion for brain death. Here we discuss a case of brain death confirmed by a reliable and quick method using Tc 99m DTPA cerebral perfusion scan following a krait bite. Key words: Cerebral perfusion scanning; "hot nose" sign DOI: 10.4038/cmj.v50i4.1409 Ceylon Medical Journal Vol.50(4) 2005: 165-166

/pdf/brain-death-confirmed-by-tc-99m-dtpa-scan-in-a-case-of-47iya1tlup.pdf

Brain death confirmed by Tc 99m DTPA scan in a case of subarachnoid haemorrhage following a krait bite

Analysis of the reports of high-level commissions that have comprehensively reviewed US public policy on brain death.

Laws and standards of medical practice with respect to the determination of death have changed dramatically as knowledge of the human body and its detailed cellular functions have increased. This article describes legal and medical advances in the determination of death emphasizing the role of modern imaging technology in this critical determination.

S J Morayati

Papers

The determination of death and the changing role of medical imaging.