Per procedure, plateletapheresis may remove 2 X 10(9) to 3 X 10(9) white cells from the peripheral blood of a normal donor. To investigate the effects of frequent and sustained plateletapheresis, multiple peripheral blood tests were performed on 25 volunteer donors undergoing plateletapheresis an average of 72 times over periods of up to 8 years, and results were compared with 25 age- and sex-matched controls who had not undergone apheresis. In donors, significant decreases were observed in: 1) both absolute number and percentage of T4+ cells; 2) absolute number of both T8+ cells and Leu-7+ cells; 3) T4/T8 ratio; 4) responses to both pokeweed mitogen and alloantigens; and 5) IgG levels. Significant increases were observed in percentages of both B cells and monocytes, and responses to both phytohemagglutinin and Concanavalin A. Plateletapheresis removes a large number of T4 and T8 cells, a moderate number of B cells, and a smaller number of monocytes and Leu-7 cells. The results suggest that during vigorous plateletapheresis the replenishment to peripheral blood per month was less than 1.83 X 10(9) and 0.93 X 10(9) for T4 cells and T8 cells, respectively, greater than 0.27 X 10(9) and 0.62 X 10(9) for B cells and monocytes, respectively, and approximately 0.39 X 10(9) for Leu-7 cells. Although no clinical effect was noted, these data suggest that frequent and sustained non-lymphocyte sparing plateletapheresis is associated with changes in laboratory findings related to the immune system.

Adolescent↗

PubMedDate not supplied

Pentobarbital therapy for intracranial hypertension in metabolic coma. Reye's syndrome.

In severe Reye's syndrome, with nonspecific intensive supportive therapy, the mortality rate approaches 75%. In many instances, death is due to uncontrolled cerebral edema and elevated intracranial pressure. (ICP). Pentobarbital therapy, sufficient to maintain a blood barbiturate level between 2.5 mg% and 4.0 mg%, was used to control ICP in seven patients with metabolic coma complicated by intracranial hypertension (intracranial pressure greater than 30 mm Hg for 30 min). The nadir of their neurological function was characterized by no response to deep pain, absent or abnormal oculocephalic responses, bilaterally dilated, unreactive pupils, and markedly irregular or absent respirations. Before barbiturate administration hyperventilation, steroids, mannitol, and other supportive therapies commonly used in Reye's syndrome were begun. After institution of pentobarbital therapy, the daily mannitol dose required to maintain the intracranial pressure below 20 mm Hg was significantly reduced (p less than 0.001), from 3.7 +/- 0.3 to 0.5 +/- 0.2 g/kg/day. All the patients survived, and six have no obvious neurological sequelae. Pentobarbital is a useful adjunct for intracranial pressure control in advanced metabolic coma.

Adolescent↗

PubMedDate not supplied

Examination by computerized axial tomography.

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Adult↗

PubMedDate not supplied

Direct thermometry, ophthalmodynamometry, auscultation and palpation in extracranial cerebrovascular disease: an evaluation of rapid diagnostic methods.

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Aged↗

PubMedDate not supplied

Ventricular fibrillation in the cat: a model for global cerebral ischemia.

A minimally invasive and standardized means of resuscitating cats from defined periods of ventricular fibrillation (VF) has been developed using methods little different from human cardiopulmonary resuscitation techniques. After a 12 min arrest, the rate of successful resuscitation is greater than 90%, witha resuscitation time of 2.5 +/- 0.7 (SD) min, and a 7 day survival of 70%. All deaths could be related to a specific electroencephalographic event observed acutely post-resuscitation, and were not due to obvious non-neurologic complications. The post-arrest variation in a variety of parameters (blood pressure, blood gases, etc.) was minimal, and the degree of neurologic damage was severe enough to permit evaluation. Such a model is clinically relevant, and may be useful in studying the pathophysiology of global ischemia, and assessing different types of post-arrest therapy.

Animals↗

PubMedDate not supplied

Automatic end-tidal gas sampling system for non-invasive rCBF measurements.

Non-invasive measurements of regional cerebral blood flow (133Xe inhalation or IV injection) require knowledge of the arterial 133Xe concentrations, which is usually estimated from the end-tidal expiration. An automated sampling system is described for measurement of end-tidal 133Xe concentration that can be used in both spontaneously breathing and mechanically ventilated patients. A comparison is made between the automatic sampling system and manual measurements performed on a continuous gas sample.

Blood Gas Analysis↗

PubMedDate not supplied

The influence of diurnal rhythms in patients with intracranial hypertension: implications for management.

Decompensation of brain injured patients during the night is common and has been attributed to the retention of CO2 during sleep. When CO2 is controlled, such nocturnal decompensation needs another explanation; consequently, the records of 21 consecutive patients with acute closed head injuries and increased intracranial pressure were reviewed. There were 185 separate episodes of intracranial hypertension (30 mm Hg or more for 10 minutes or more) in the 21 patients, 124 of which (67%) occurred between 4:00 a.m. and 9:00 a.m. (p less than 0.01). Intravenous pentobarbital (3 to 5 mg/kg) was effective in reducing the intracranial pressure (ICP) to normal levels during 104 of the 124 early morning episodes (84%), whereas mannitol was less effective (7 of 17; 41%). This suggests that an increase in brain blood volume directly related to diurnal rhythm is responsible for the increase in ICP. Severe bradycardia and systemic arterial hypertension were unreliable predictors of elevation in ICP. They preceded or accompanied less than one-fourth of the episodes.

Bradycardia↗

PubMedDate not supplied

Fluctuating intracranial hypertension due to Cheyne-Stokes respiration.

Cyclically fluctuating intracranial pressure (ICP) with periodic breathing was first described by Nils Lundberg in 1960. While Cheyne-Stokes respiration (CSR) frequently accompanies severe cerebrovascular accidents, it is not commonly appreciated that cycles of severe intracranial hypertension can complicate this abnormal ventilation pattern. We recently treated a patient with a hemorrhagic stroke in whom episodes of elevated ICP were synchronously associated with CSR.

Aged↗