Problems associated with the apnea test in the diagnosis of brain death.

BACKGROUND: Brain death is the absence of all cortical functions, including the brainstem. The apnea test (AT) is a necessary requisite to complete this diagnosis. Anecdotal reports describing hypotension and acidosis due to apnea test have been reported. However, there are few studies that evaluate complications or difficulties related to this procedure. OBJECTIVE: To analyze medical problems associated with the apnea test. METHODS AND PATIENTS: We analyzed clinical features, potential risk conditions, and problems in 129 brain dead patients during the apnea test. The diagnosis of brain death was made according to the American Academy of Neurology recommendations. RESULTS: Clinical problems during the apnea test were detected in more than two thirds of patients, including: arterial hypotension (12%), acidosis (68%), and hypoxemia (23%). Four patients developed major complications, including: pneumothorax, cardiac arrest, bradycardia, atrial fibrillation and myocardial infarction. CONCLUSION: The apnea test is not an innocuous procedure. Complications during the AT are more common than reported and limit organ procurement for transplantation. Guidelines for performing the AT should be followed in order to avoid clinical complications.

Cataleptic postures in thalamic hemorrhage: case report

We report a case of catalepsy associated with thalamic hemorrhage. A 72 year-old hypertensive woman had acute onset of right-sided weakness and speech disturbances. She was on anticoagulants because of aortic valve replacement. When postures were imposed, the patient maintained the left upper limb raised for several minutes, even in uncomfortable or bizarre positions. A CT scan of the head revealed a left thalamic hemorrhage. Cataleptic postures have been reported in few cases with acute stroke

Pneumothorax and pneumoperitoneum during the apnea test: how safe is this procedure?

Apnea test is a crucial requirement for determining the diagnosis of brain death (BD). There are few reports considering clinical complications during this procedure. We describe a major complication during performing the apnea test. We also analyse their practical and legal implications, and review the complications of this procedure in the literature. A 54 year-old man was admitted for impaired consciousness due to a massive intracerebral hemorrhage. Six hours later, he had no motor response, and all brainstem reflexes were negative. The patient fulfilled American Academy of Neurology (AAN) criteria for determining BD. During the apnea test, the patient developed pneumothorax, pneumoperitoneum, and finally cardiac arrest. Apnea test is a necessary requirement for the diagnosis of brain death. However, it is not innocuous and caution must be take in particular clinical situations. Complications during the apnea test could be more frequent than reported and may have practical and legal implications. Further prospective studies are necessary to evaluate the frequency and nature of complications during this practice

Arteriosclerosis and the promise of GPIIb/IIIa inhibitors in stroke

Ischemic mechanisms in patients with brain and heart attacks have been studied for more than 150 years. Antiplatelets agents did show benefit in secondary prevention. Aspirin is the most common antiaggregant in clinical use today. However, the benefit produced by the "best" antiplatelet regimen in stroke prevention is lower than 40 per cent. The adherence of circulating platelets to the subendothelium is mediated by glycoprotein (GP) residing on the cell's surface. GPIIb/IIIa is the most important platelet membrane receptor that mediates the process of platelet aggregation, and thrombus formation. Thus, new drugs that block the GPIIb/IIIa receptor have recently emerged. Clinical trials using these agents have shown effectiveness in acute coronary syndromes. However, the absence of studies in cerebrovascular disease and the potential hemorrhagic complications questioned their use in stroke prevention. We review the clinical trials using the new GPIIb/IIIa agents in myocardial ischemia, and consider the potential implications for cerebrovascular disease.