J. Van Aken

In vitro evaluation of the effect of profound haemodilution with hydroxyethyl starch 6%, modified fluid gelatin 4% and dextran 40 10% on coagulation profile measured by thromboelastography.

Synthetic colloids have been implicated as a cause of coagulopathy when administered in large quantities. The effect of profound haemodilution (50%) on coagulation profile was measured in vitro by thromboelastography. Blood samples were taken from 11 ASA grade 1 patients prior to induction of anaesthesia for elective surgery. Each sample was simultaneously tested in four different preparations: undiluted blood (control sample); blood diluted with hydroxyethyl starch 6%; blood diluted with modified fluid gelatin 4%; blood diluted with dextran 40 10%. There was a significant decrease in reaction time in the preparations treated with hydroxyethyl starch 6% and modified fluid gelatin 4%, reflecting activation of initial fibrin formation. A significant increase in clot formation time was noted in the hydroxyethyl starch 6%‐treated preparations. There was also a significant decrease in clot formation rate and maximum amplitude in the hydroxyethyl starch 6% group. Clot formation time, clot formation rate and maximum amplitude did not change in the modified fluid gelatin 4% group. Profound haemodilution with dextran 40 10% exerted extreme effects on the measured variables, very often resulting in a straight line on the thromboelastography profile.

Cerebral Blood Flow and Oxygen Metabolism in Leuko-Araiosis

Regional blood flow and oxygen metabolism were determined by positron emission tomography using the steady-state technique with O-15, in 2 patients with posthypoxic ischemic leukoencephalopathy, in 6 patients with leuko-araiosis and dementia, and in 6 patients with leuko-araiosis without dementia. Comparison between the three groups allowed us to conclude that leuko-araiosis is associated with a lowered cerebral blood flow, which is more pronounced and widespread in demented patients and more restricted to the white matter in nondemented ones.Regional blood flow and oxygen metabolism were determined by positron emission tomography using the steady-state technique with 150, in 2 patients with posthypoxic ischemic leukoencephalopathy, in 6 patients with leuko-araiosis and dementia, and in 6 patients with leuko-araiosis without dementia. Comparison between the three groups allowed us to conclude that leuko-araiosis is associated with a lowered cerebral blood flow, which is more pronounced and widespread in demented patients and more restricted to the white matter in nondemented ones.

Positron emission tomography studies of changes in cerebral blood flow and oxygen metabolism in arteriovenous malformation of the brain.

Two patients with arteriovenous malformation were studied by position emission tomography, using the steady-state technique with 15O2. In the first patient, who had seizures, preceded by auditory hallucinations, an area of decreased cerebral blood flow and oxygen consumption was shown just behind the malformation. In the second patient, who had repeated attacks of right hemiparesis, an area of decreased blood flow and oxygen metabolism was shown at distance of the malformation. These areas of low flow and metabolism are most probably the result of a vascular steal phenomenon and the origin of the transient neurological symptoms in both patients.

Positron Emission Tomographic Studies of Changes in Cerebral Blood Flow and Oxygen Metabolism in Neuroleptic Malignant Syndrome

Three patients with neuroleptic malignant syndrome were studied by positron emission tomography (PET), using the steady-state technique with C15O2 and 15O2. In 2 patients the PET examination was repeated after resolution of the syndrome. In 2 patients, under treatment with bromocriptine, high blood flow and oxygen metabolism were demonstrated in the striatum, cerebellum and occipital cerebral cortex during the neuroleptic malignant phase, showing that not only the dopaminergic system is disturbed but also other neurotransmitter systems are involved. In the 3rd case the PET scan findings were not as conclusive.

A large intracranial xanthoma in familial hypercholesterolemia

Intracranial xanthomata occurring in patients with familial hypercholesterolemia are very rare. We present a young woman with a large intracranial xanthoma. The patient was treated for a familial hyperlipoproteinemia type IIa. MRI and morphological features are shown and discussed on reviewing the literature.

The position of the patient during neurosurgical procedures on the posterior fossa

SummaryDifferent parameters were measured on patients in six different positions during infratentorial surgery. One group of data served to prove that such patients were in a steady-state as far as their cardiovascular and ventilatory function was concerned. The other measured parameters concerned the intracranial pressure, the intracranial venous pressure and the cerebral perfusion pressure. It appeared from the comparison of these data, that the lateral sitting (45°) position had important advantages and that in this position the possibility of unfavourable features (such as air-embolism) was minimized.

Delayed Neurological Deterioration following Acute Carbon Monoxide Poisoning: Comparison of Clinical Outcome, Neuro-Imaging and Positron Emission Tomography Findings

In 8 patients with delayed neurological deterioration, following acute CO poisoning, the clinical outcome, the neuroimaging and the positron emission tomography (PET) findings were compared. The severity of the neuropsychiatric sequelae correlated well with the changes of blood flow and oxygen metabolism and the CT scan findings in the brain. Nuclear magnetic resonance (NMR) appeared to have less predictive value on the clinical outcome. In the severe cases of post-CO encephalopathy, the ischemic nature of the metabolic changes could be demonstrated in the cortical regions by PET. However, it could not be determined whether the disturbances in the basal ganglia and cerebral white matter were only due to ischemia or to an additional cytotoxic effect of CO.

Rapidly progressive pulmonary artery hypertension and end-stage liver disease

Pulmonary hypertension is a recognized but unusual complication of liver disease. It can complicate the perioperative course of liver transplantation. Mild to moderate pulmonary hypertension is generally well tolerated during the procedure and does not appear to contribute to mortality.

Influence of Enflurane on Cerebral Blood Flow in Man

Cerebral blood flow was measured by means of a 10‐channel cerebrograph in anesthe‐tised patients before and during 2% enfluranc. This investigation was carried out after carotid angiography; 2 3 mCi Xe133 was injected into the internal carotid artery. The clearance curves of Xel33 were captured by 10 scintillation counters. In addition to regional cerebral blood flow (rCBF), arterial blood pressure, heart rate, stroke volume, cardiac output and arterial blood gases were measured in seven adult patients.