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Biomedical subjects

E Enevoldsen

Publications and source records attributed to E Enevoldsen.

At least 19 recordsLinked to original sources
PubMed1998

Percutaneous transluminal angioplasty in selected patients with severe carotid artery stenoses: the results of a consecutive series of 24 patients.

OBJECTIVES: To assess clinically and with duplex scanning the results of percutaneous transluminal angioplasty in a subgroup of patients with carotid artery stenosis. DESIGN: A retrospective study. MATERIALS: Twenty-four patients with focal hemispheric neurological symptoms from a concentric, smooth carotid stenosis more than 70% treated with balloon dilatation. Control investigations were performed with duplex scanning. RESULTS: Angiography after PTA revealed no residual stenosis in 15 patients (62%), a stenosis of less than 50 was seen in seven patients (30%) and PTA was ineffective in two patients (8%). Three patients (13%) had transient ischaemic attacks during the procedure but none had strokes. One patient experienced short lasting paraesthesia of the arm a few hours after the PTA procedure. After a follow-up of a mean of 11 months (1-38) no recurrent symptoms had occurred. Clinical success was thus achieved in 22 of 24 patients (92%). At duplex scanning, 16 (66%) patients had no stenosis, six patients (30%) had a stenosis of 70%, one patient (4%) a stenosis of 80%, and one patient had an occluded carotid artery. CONCLUSION: Our results indicate that PTA in a selected group of patients with carotid artery stenosis is safe and the interim, long-term results are promising. The procedure must be evaluated in a randomised prospective study against surgical treatment.

Aged↗
PubMed1993

[Apoplexy--the acute phase].

This review concerns the acute phase of stroke. It describes incidence, prevalence, etiology, diagnosis and treatment together with the possibilities for prevention. The incidence of stroke in the Danish population is about 2/1000 person years and has been largely unchanged during the last 20 years. About 85% of strokes are caused by cerebral infarcts, ten percent by intracerebral haemorrhages and about five percent by subarachnoid bleeding. The incidence increases with age. Up till age 65 years the ratio between men and women is two to one, while the ratio in the oldest age group approaches one to one. The most important risk factors for stroke are smoking, arterial hypertension, previous cerebrovascular disease, heart disease and diabetes mellitus. Till now, no treatment has been documented as effective in reducing the cerebral damage caused by acute stroke. Ongoing controlled clinical trials in the acute state of ischaemic stroke are testing the effect of thrombolytic therapy, treatment with calciumantagonists, aspirin and heparin. The general medical treatment including nursing and physiotherapy in the acute phase is described. Within recent years benefit of various strategies of stroke prevention has been documented.

Acute Disease↗
PubMed1993

Transcranial Doppler recordings in raised intracranial pressure.

The pulsatility index (PI) registered by the transcranial doppler (TCD) was examined in relation to arterial pCO2 (paCO2) and epidural pressure (ICP). In 10 normal subjects PI was studied during variations in paCO2. In 10 neurosurgical patients with head injuries concomitant measurements of PI and ICP were obtained. The results showed a negative exponential correlation between PI and paCO2. PI changes with 3.2% pr mmHg paCO2. A positive exponential correlation between PI and ICP was observed. PI changed with 2.4% pr mmHg ICP. In the subgroup of patients with raised ICP (15 mmHg <) paCO2 was found not to influence the PI-reflection of the ICP, probably because paCO2-changes affected PI as well as ICP. The results suggest that the noninvasive bedside TCD-registration may be a useful marker of the ICP and probably replace the former invasive methods of measuring ICP.

Adolescent↗
PubMed1993

[Apoplexy--the acute stage].

This review concerns the acute phase of stroke. It describes incidence, prevalence, etiology, diagnosis and treatment together with the possibilities for prevention. The incidence of stroke in the Danish population is about 2/1000 person years and has been largely unchanged during the last 20 years. About 85 per cent of strokes are caused by cerebral infarcts, ten percent by intracerebral haemorrhages and about five per cent by subarachnoid bleeding. The incidence increases with age. Up till age 65 years the ratio between men and women is two to one, while the ratio in the oldest age group approaches one to one. The most important risk factors for stroke are smoking, arterial hypertension, previous cerebrovascular disease, heart disease and diabetes mellitus. Till now, no treatment has been documented as effective in reducing the cerebral damage caused by acute stroke. Ongoing controlled clinical trials in the acute state of ischaemic stroke are testing the effect of thrombolytic therapy, treatment with calcium antagonists, glutamate receptor antagonists, aspirin and heparin. The general medical treatment including nursing and physiotherapy in the acute phase is described. Within recent years benefit of various strategies of stroke prevention has been documented.

Acute Disease↗
PubMed1991

Cerebral blood flow and metabolism following subarachnoid haemorrhage: effect of subarachnoid blood.

The amount of effused blood following a subarachnoid haemorrhage (SAH) was estimated in 48 patients by cerebral computerized tomographic scanning. The cerebral oxygen consumption (CMRO2) was calculated as arteriovenous difference for oxygen multiplied by mean cerebral blood flow measured by the 133-Xe inhalation technique. A significant negative correlation was observed between CMRO2 and amount of subarachnoid blood, with additional reduction in CMRO2 in case of ventricular bleeding. Cerebral blood flow on admission, opposed to CMRO2, showed no correlation to amount of blood on CT scan. A correlation was observed for blood flow measured at day 5 and further on, indicating a restored coupling between flow and metabolism. The clinical (Hunt) grade on admission and the outcome correlated to the amount of blood. These observations suggest that the acute reduction in CMRO2 following a SAH is mainly determined by the amount of blood escaping during the aneurysm rupture, and that the cerebral blood flow level a few days after SAH mainly is determined by the initial reduction in oxygen uptake.

Blood Flow Velocity↗
PubMed1990

Spasm index in subarachnoid haemorrhage: consequences of vasospasm upon cerebral blood flow and oxygen extraction.

A spasm index, defined as transcranial Doppler detected flow velocity in the middle cerebral artery divided by regional cortical cerebral blood flow (CBF), was used on 24 patients with subarachnoid haemorrhage (SAH). The aim was to estimate degree and time course of vasospasm, even in cases with great day-to-day variation in CBF, and correlate to CBF and oxygen extraction. All patients showed increase in spasm indices with peak index in the second or third week. The index seemed stable in spite of day-to-day fluctuations in CBF. Severe vasospasm were associated with poor clinical condition, reduced CBF (less than 30) and high AVDO2. The same picture could be seen with minor degree of vasospasm, probably, in some cases, due to high intracranial pressure. The results suggest that the spasm index is useful in monitoring patients with subarachnoid haemorrhage, and that severe vasospasm has a negative influence on clinical condition, CBF and oxygen extraction.

Blood Flow Velocity↗
PubMed1990

Cerebral blood flow and metabolism following subarachnoid haemorrhage: cerebral oxygen uptake and global blood flow during the acute period in patients with SAH.

Forty-eight patients with subarachnoid haemorrhage were studied with repeated rCBF and CMRO2 measurements. Cortical rCBF was measured using xenon-inhalation technique. CMRO2 was calculated as AVDO2 x CBF. When first studied the 29 conscious patients showed relative hyperaemia with CBF at 50 ml and reduced CMRO2 at 2.17 ml. In the following week CBF decreased to 41. CMRO2 remained reduced and constant. The 19 unconscious patients showed initially pronounced reduction in CMRO2 to 1.26, followed by gradual increase to 1.73 in 4-5 days. Simultaneously CBF increased from 18 ml to slightly above 30 ml. In the conscious patients the early reduction in CMRO2 and the concomitant luxury perfusion may be explained by global ischaemia because of very high ICP at the time of the haemorrhage. The reduced CBF in the unconscious group could be due to increased ICP, as ventricular drainage increased CBF to levels of relative hyperaemia as demonstrated in one case. As no decrease in CMRO2 was seen during the first 2 weeks, it is suggested that ischaemia at the time of aneurysm rupture is the most important single factor in reduction of global CMRO2.

Adult↗
PubMed1990

Problems in cerebral blood flow calculation using xenon-133 in patients with pulmonary diseases.

We used the end-tidal concentration of xenon-133 (air curve) to estimate the profile of its arterial concentration in calculating cerebral blood flow. We examined the effects of pulmonary disease and artificial ventilation on the air curve and the calculated cerebral blood flow. We studied the relation between arterial and end-tidal xenon activities in 19 subjects, of whom 15 had pulmonary dysfunction. The t 1/2 of the declining phases of the arterial and air curves were used to express their shapes. The mean +/- SD reference t 1/2 from 15 normal volunteers was 26.8 +/- 8.4 seconds. The mean +/- SD t 1/2 s of the air and arterial curves from the 15 patients with pulmonary dysfunction were 10.4 +/- 2.9 and 33.8 +/- 10.9 seconds. The degree of pulmonary dysfunction (expressed as the pulmonary shunt percentage) correlated with distortion of the air curve. Substituting the arterial for the air curve, mean calculated cerebral blood flow (as the initial slope index) increased from 40 to 61 for the 12 patients with chronic obstructive pulmonary disease. The degree of underestimation of cerebral blood flow using the air curve correlated with the pulmonary shunt percentage. Our work confirms the problems of estimating cerebral blood flow in subjects with pulmonary dysfunction.

Adult↗
PubMed1989

Retrograde catheterization of the right internal jugular vein for serial measurements of cerebral venous oxygen content.

Serial measurements of CBF and metabolism require multiple cerebral venous blood samples. Retrograde catheterization of the right internal jugular vein is easily performed at a point 2.5-3 cm lateral to, and 2 cm above, the medial end of the right clavicula. Complications are few and minor. In 1/80 (1.25%) cases the carotid artery was punctured during cannulation. Insertion of the catheter for 16-18 cm reduces contamination with extra-cerebral blood to a minimum.

Catheterization, Central Venous↗
PubMed1986

CBF in head injury.

In the last few years the possibility of measuring CBF by means of intravenous isotop injection technique and portable monitor has made the use of measuring CBF in the clinical setting of the brain injured patient of current interest. However, knowledge about the hemodynamics of the head trauma is inevitable for the interpretation of the CBF results. In this communication a short outline of the results obtained during the last decades studies about the hemodynamic of the damaged brain is given. The essence of these studies seems to be: The local level of CBF do not indicate the severity of the brain injury, as low as well as high flow may be seen initially in severely injured brain tissue. The oxygen uptake (CMRO2) is related to the severity of the brain trauma, as low CMRO2 correlate to poor clinical condition. In severely damaged brain tissue the autoregulation may appear normal (false autoregulation) whereas the autoregulation in moderately damaged tissue may appear impaired for weeks. The carbon dioxide response (CO2) is only impaired if the brain tissue is severely damaged. Thus, low CMRO2 and dissociation between apparently normal autoregulation and impaired CO2 response seem to predict poor outcome.

Brain↗
PubMed1986

Reversible ischemic neurological deficit and minor strokes before and after EC/IC bypass surgery. A neuropsychological study.

Thirty-three patients with reversible ischemic deficits or completed minor strokes had their cerebral function measured neuropsychologically a few days before and 3 months after extra-intra cranial bypass surgery. Three months post-operatively bypass patency was demonstrated by angiography. Ten patients were operated on the right side and 23 on the left side. The right hemisphere patients were found to be neuropsychologically intact or only slightly impaired before, as well as after, the operation whereas the left hemisphere patients pre-operatively had impaired verbal sequential thinking, reduced capacity for repetition, verbal learning, and mental arithmetic. Post-operatively they improved significantly on 5 of 15 tests and performed no worse on any test than the control group. Consequently, they, too, had post operatively no or only slight neuropsychological impairment.

Adult↗
PubMed1985

A neuropsychological study of 12 patients with transient ischemic attacks before and after EC/IC bypass surgery.

A neuropsychological study of 12 patients with transient ischemic attacks from the carotid artery territory was carried out about 2 months following their latest attack, about a week before STA/MCA bypass operation, and again 3 months postoperatively. The results suggest that the TIA patients as a group were slightly intellectually impaired preoperatively. After the operation, a minor neuropsychological improvement had taken place although they still were not fully intellectually rehabilitated.

Cerebral Revascularization↗
PubMed1977

Cerebral hemodynamics in migraine.

Clinical and angiographic findings in migraine are briefly reviewed in relation to cerebral hemodynamic changes shown by regional cerebral blood flow (rCBF) studies. Three cases of migraine studied by the intracarotid xenon 133 method during attacks are reported. In classic migraine, with typical prodromal symptoms, a decrease in cerebral blood flow has been demonstrated during the aura. Occasionally, this flow decrease persists during the headache phase. In common migraine, where such prodromata are not seen, a flow decrease has not been demonstrated. During the headache phase of both types of migraine, rCBF has usually been found to be normal or in the high range of normal values. The high values may represent postischemic hyperemia, but are probably more frequently secondary to arousal caused by pain. Thus, during the headache phase rCBF may be subnormal, normal or high. These findings do not exclude the possibility of distension of the larger intracranial arteries during migraine headache, but the angiographic evidence, however limited, does not support this speculation.

Adult↗
PubMed1975

Ventricular fluid lactate, pyruvate, bicarbonate and ph in unconscious brain-injured patients subjected to controlled ventilation.

In 35 unconscious patients suffering from traumatic brain injury and subjected to controlled hyperventilation within 12 hours of the acute trauma, we measured continuously the intraventricular pressure (IVP), ventricular fluid lactate, pyruvate, L/P ratio, pH and bicarbonate during the first 4 posttraumatic days, and related the findings to the clinical course. In patients in whom the follow-up study did not reveal severe mental impairment or dementia, the ventricular fluid lactate never exceeded 4 mmol/litre. In this group, the IVP level never exceeded 40 mmHg/hour, and the mean pressure/day never exceeded 20 mmHg. In half of the patients in whom dementia, vegetative survival or death occurred, ventricular fluid lactate exceeded 4 mmol/litre; the IVP level/hour exceeded 40 mmHg in two of 23 patients, and the mean pressure/day exceeded 20 mmHg in nine of 23 patients. The prognostic value of pyruvate was of less importance, although a significant increase in patients with a poor outcome was seen. No prognostic conclusions could be drawn from ventricular fluid, L/P ratio, pH and bicarbonate.

Bicarbonates↗
PubMedDate not supplied

Focal cerebral hyperemia in acute stroke. Incidence, pathophysiology and clinical significance.

In a consecutive study comprising 41 patients with completed stroke of less than 72 hours duration, cerebral angiography and measurements of the regional cerebral blood flow (rCBF) were performed within 24 hours after admission. The rCBF study was done using the 133-Xenon intracarotid injection method and a 254 multi-detector camera. CT scan was done 24 hours after the rCBF study. Focal cerebral hyperemia was found in 16 patients. The study revealed 3 different types of hyperemia: Border-zone hyperemia, surrounding ischemic areas, was seen in patients with occluded arteries on angiography, presumably resulting from accumulation of acid metabolites in the border-zone of acute infarcts. Postischemic hyperemia was seen in patients without occlusion, presumably due to recanalization of a prior occluded artery. Remote hyperemia was found distant from the infarcted area, presumably due to local tissue pressure on brain tissue. Cortical infarcts (10 patients) all had extensive hyperemic areas. Because the 254 detector camera has an excellent resolution in the cortical surface, our findings strongly suggest that all acute cerebral infarcts are, in fact, associated with hyperemic areas. The hyperemic areas are often extensive and vascular reactivity is commonly impaired. It is suggested that treatment aimed at reducing blood flow in hyperemic areas might improve prognosis.

Aged↗