Neurologists in Colorado and California were asked the methods they use to test for apnea when determining brain death. Most (65.1%) of 129 respondents simply observed the patient for respiratory efforts for 3 minutes or less while off the ventilator. Only 22.5% measured arterial carbon dioxide, 12.4% used a published recommended rigorous method for testing for apnea, and 11.6% did not test for apnea. Clinicians in full-time academic practice more frequently used the rigorous method. The data indicate that methods used most often in the communities surveyed are less rigorous than published guidelines.

AN UNRESOLVED question is whether during seizures lactic acidosis occurs in brain tissue because cerebral oxygen delivery fails to meet the augmented demands of cerebral oxidative metabolism. Several investigators have reported that brain lactate concentrations increase during experimental seizures in mice, cats, dogs, and monkeys.1-6 Also, during induced generalized and focal seizures in man, falls in jugular venous pH have been observed.7 From these findings it has been inferred that cerebral metabolism rises so sharply during seizures that it outstrips the available oxygen supply, which results in a shift to anaerobic glycolysis and increasing lactate formation by brain tissue.6 However, recent studies from this laboratory imply that brain lactate does not necessarily increase during induced cerebral seizures. Using dogs and monkeys that were artificially ventilated and paralyzed, Plum and his associates8 found that, although cerebral oxygen consumption increased substantially during induced seizures, cerebral blood flow increased proportionately even more so that the sagittal venous blood oxygen tension and content also rose. Thus, during cerebral seizures the oxygen supply to the brain met or exceeded the heightened cerebral metabolic demand. During cerebral seizures lactate dif¬ ferences between arterial and sagittal venous blood did not increase and the concentration of lactate in the cerebrospinal fluid (CSF) did not change significantly.The above findings suggested that during seizures brain tissue lactate formation does not rise if adequate arterial oxygénation is maintained. We sought to confirm this hy¬ pothesis by measuring brain lactate concen¬ trations and other parameters in paralyzed animals before and during experimental cere¬ bral seizures. Studies were done in 12 well-oxygenated dogs and in three dogs that were allowed to become hypoxic. It was found that during the seizure discharge in the well-oxygenated animals brain lactate concentrations did not rise significantly, but during seizures in the hypoxic animals brain lactate rose nearly twofold. MethodsFifteen healthy mongrel dogs were initially anesthetized with thiopental sodium intrave¬ nously, given atropine 1 mg intravenously, and intubated with cuffed endotracheal tubes. Cannulae were placed in both femoral arteries to monitor blood pressure and obtain blood sam¬ ples, and, in one femoral vein, to give fluids and medications. The dogs were placed prone, con¬ nected to a respirator, and paralyzed with gallamine. Anesthesia was maintained with a Changes in brain lactate during seizures. 70%/30% nitrous oxide/oxygen mixture. Bilat¬ eral craniotomies were performed and a wide skull cap was removed exposing both cerebral hemispheres and the sagittal sinus. The dura was left intact until the time of brain biopsy and kept warm and moist with saline packs and the heat from an operating lamp. A cannula was placed in the sagittal sinus to obtain cere¬ bral venous blood samples. Another cannula was placed percutaneously in the cisterna mag¬ na to ...

Brain stem glioma is the third most common childhood brain tumor, comprising 10–15% of this group of neoplasms. Typical presenting symptoms include ataxia, diplopia and headache, while signs of increased intracranial pressure occur later in the clinical course. Although prolonged failure to thrive, characterized by cachexia and vomiting are rare manifestations of brain stem lesions, in this study we report a 9.5-year-old boy with failure to thrive since infancy which remitted after excision of a brain stem astrocytoma.

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This study included 49 patients with clinical multiple sclerosis (MS), 105 patients with other neurological diseases (OND), and 30 controls. It compared seven assays for CNS IgG synthesis with the oligoclonal banding (agarose electrophoresis) method. A newly developed assay which determined the differences between the measured and calculated CSF/serum IgG ratio (M-C value), using albumin as a reference protein, was particularly sensitive to the diagnosis of MS. In 40/46 (87%) of patients with MS, the M-C value was 0.001 or more, while oligoclonal banding was found in CSF of 38/49 (78%). In the 30 controls, the M-C value was invariably less than 0.001 and oligoclonal banding was not found. In patients with OND, 26/104 (25%) had an M-C value of 0.001 of greater while 11/105 (11%) had oligoclonal banding in CSF. The M-C value also offers a convenient means of quantifying CNS IgG synthesis during disease activity of treatment. It is concluded that the combined use of the oligoclonal banding method and the M-C value determination gives the greatest predictive value for the diagnosis of MS.