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Biomedical subjects

Z Czernicki

Publications and source records attributed to Z Czernicki.

At least 19 recordsLinked to original sources
PubMed1992

Intracranial volume reserve determination using CT images, numerical analysis and lumbar infusion tests. An experimental study.

The epidural balloon compression model in the cat was used in intracranial volume reserve studies. The evaluation of the intracranial volume-pressure relations was based on the lumbar infusion test data: intracranial pressure, CSF outflow resistance, volume-pressure response and on CT images numerical analysis (CTINA) values. Two methods were applied and compared in the study: lumbar infusion test and CT images numerical analysis. The determinations were performed at the balloon volumes of 0.5 ml, 1.0 ml, and 1.5 ml. First statistically significant changes were found at the balloon volume of 0.5 ml i.e. the increase of CSF outflow resistance and volume-pressure response (data obtained in lumbar infusion test) and the decrease in CTINA values. The rise of intracranial pressure was less informative as it was observed at the balloon volume of 1.5 ml. Therefore CTINA seems to be a very useful noninvasive screening method in clinical studies of intracranial volume reserve.

Animals↗
PubMed1992

ICP dependent changes of CSF outflow resistance.

CSF outflow resistance was studied in cats using the lumbar infusion tests. Different infusion rates were applied from 0.012 to 1.8 ml/min. ICP level obtained during infusions varied from 8.9 +/- 3.0 to 144.0 +/- 25.7 mmHg. The calculated resistance (R) values were within 75.2 +/- 14.4 to 255.6 +/- 71.2. mm Hg/ml/min. The relation between ICP and R are characterized by a curve which can be divided into three parts. First R rises until an ICP level of about 20 mmHg is reached, then R decreases fast until the ICP value is about 50 mmHg, a further drop is much slower and the ICP/R curve becomes almost parallel to the ICP axis. The possible reasons for the ICP dependent changes of R as well as the clinical importance of the results obtained are discussed.

Animals↗
PubMed1992

[Changes in CSF resorption resistance. Experimental studies].

Lumbar infusion tests (IT) with different infusion rates (0.06 ml/min-1.2 ml/min) were used in order to investigate the intracranial pressure (ICP) and CSF outflow resistance (R) changes. Two groups of animals were studied: control group and animals with an 0.8 ml epidural balloon. In control group (without balloon) significant differences in ICP and R values between the increasing and decreasing IT curve were found. The most pronounced changes were noticed right after the highest infusion rate (40% for ICP value and 49% for R value). The results in the balloon group were very similar and the only difference were delayed ICP and R changes. The results obtained suggest that the determined R values are specific for the applied infusion rate and this phenomenon has to be taken into account in all human studies.

Animals↗
PubMed1992

[Evaluation of the usefulness of cerebral perfusion pressure in threatened cerebral ischemia].

The Cushing response was produced using the lumbar infusions in cats. The following parameters were recorded and computed: arterial blood pressure (ABP), central venous pressure (CVP), intracranial pressure (ICP), heart rate and ECG. The lactate concentration was studied in brain stem and brain cortex. The analysis of ABP and ICP recordings showed in some cases that the Cushing response was obtained at CPP over 60 mmHg. The role of adrenergic reaction in Cushing phenomenon was confirmed by the increase in blood catecholamine concentration and typical adrenergic changes in ECG pattern.

Animals↗
PubMed1990

Evaluation of oedema spreading and intracranial volume reserve using CT image numerical analysis.

Using the cold lesion model vasogenic oedema was produced in 8 cats. The intracranial volume reserve was evaluated applying CT image numerical analysis (CTINA). Summarizing all voxels corresponding to CSF and brain tissue in 8 CT slices, the brain/CSF ratio was computed. The animals were studied at different time intervals after the lesion (2 h, 4 h, 6 h) then sacrificed and the spreading of oedema was estimated based on the BBB disturbances. The brain/CSF ratios varied from mean value of 0.043 in control animals to mean values of 0.022 in animals 6 hours after the lesion. The CTINA method was found very useful as a noninvasive screening method to study brain oedema development with a promising application in clinical practice.

Animals↗
PubMed1990

Early pathomorphological changes and intracranial volume-pressure: relations following the experimental sagittal sinus occlusion.

Saggital sinus occlusion was produced in cats. The intracranial volume-pressure relations were studied using the lumbar infusion tests. Right after occlusion ICP rised from 7.1 +/- 1.8 to 12.4 +/- 4.1 mmHg. The values of outflow resistance and volume-pressure response increased also and remained significantly unchanged with only slight decrease of the volume-pressure response. The morphometric study of the surface veins showed the dilatation of the veins draining to the occluded saggital sinus for about 10-20%. No signs of the blood-brain barrier disruption were observed.

Animals↗
PubMed1990

Application of dynamic computed tomography scan and computed tomography densitometry in the evaluation of brain volume enlargement.

Cats with brain cold injury and epidural balloon compression with sudden decompression were used as models of vasogenic or ischemic edema and vasoparalysis of the brain vessels. Dynamic CT scan and CT densitometric studies were performed to diagnose and differentiate between brain edema and vasoparalytic changes. The CT methods were found to be useful in CBF and edema zone estimation. The correlation of CT scan and CT densitometry enabled us to evaluate the degree of autoregulation disorders and can be also applied in clinical investigations.

Blood-Brain Barrier↗
PubMed1989

Alteration of intracranial pressure, cerebral blood flow, autoregulation and carbondioxide-reactivity by hypotensive agents in baboons with intracranial hypertension.

Intracranial pressure (ICP) was recorded by epidural transducer and cisterna magna catheter, and regional cerebral blood flow (rCBF) using the intraarterial Xenon 133-technique were measured in baboons with normal and during increased ICP provoked by an inflatable balloon positioned subdurally. Arterial blood pressure was altered by controlled infusion of Sodium-nitroprusside (SNP), Nitroglycerine (NG) or Trimetaphan (TMP) with the aim of reducing blood pressure by about 20%. During exflated balloon SNP provoked an increase of ICP which was more prominent than with NG and TMP. During increased ICP (due to inflation of the balloon) again SNP led to a higher further increase of ICP than both NG and TMP. rCBF rose during the state of normal ICP when SNP was infused. This was not observed with infusion of NG or TMP. When ICP was increased again by inflation of the balloon all 3 substances reduced rCBF, indicating damage to the autoregulation. CO2-reactivity as measured by induced hyperventilation with reduction of arterial CO2-tension was affected by all 3 substances thus indicating impairment of vasoconstriction during increase of ICP and simultaneous decrease of blood pressure. However, this impairment of physiological vasoconstriction was more prominent with SNP than with NG and TMP. The results indicate that all 3 substances should be used with care to reduce blood pressure during surgery or under intensive care condition, particularly in patients with increased ICP.

Animals↗
PubMed1979

Treatment of experimental brain oedema following sudden decompression, surgical wound, and cold lesion with vasoprotective drugs and the proteinase inhibitor "Trasylol".

The study was performed on 81 cats with three models of experimental brain oedema: sudden decompression, surgical wound, and cold injury. During the experiments blood pressure, central venous pressure, and intracranial pressure were recorded. The blood-brain-barrier was tested with Evans blue solution. The gray and white matter tissue was sampled at the end of the experiment, and the water content and sodium and potassium concentrations were determined. The animals with the same experimental model were divided into three groups: untreated, treated with the vasoprotective agents, and treated with the protease inhibitor Trasylol. In the sudden decompression model after balloon deflation, white matter haemorrhages and oedema development were found in gray matter and basal nuclei. In animals treated with the vasoprotective drugs, haemorrhages were not observed, and oedematous changes were less pronounced. The Trasylol effect on oedema development was not significant in this model. In the surgical wound model, oedematous changes were observed after 24 hours following the lesion. Oedema occurred in the white matter, as in the animals with cold lesions. In both models--surgical wound and cold lesion--the beneficial effect of Trasylol was shown, while the effect of Aescorin was less evident. The results obtained seemed to testify to the usefulness of both Trasylol and vasoprotective drugs in the prevention and treatment of brain oedema in neurosurgical patients.

Animals↗
PubMed1979

[Use of haemodilution in the treatment of cranio-cerebral injuries (author's transl)].

By decreasing blood viscosity and vascular resistance normovolemic haemodilution increases cerebral blood flow and improves microcirculation. This eliminates the symptoms of anoxia of cerebral tissue. The extent of disturbances of the blood brain barrier is decreased. The case presented in this paper illustrates the use of the above-mentioned properties of haemodilution and concerns a patient with chronic subdural haematoma. The patient's status in the pre-operative period was very poor. Craniotomy and avacuation of the haematoma did not result in a visible improvement of the patient's state. He did not regain consciousness and even lost spontaneous respiratory function. Haemodilution /Hct 29%/ was performed using Dextran 60 and 5% human albumin in the proportions 1 : 1. As a result, spontaneous respiration was restored and there was a gradual improvement in the patient's status. 29 days later it was possible to communicate with the patient. The authors are of the opinion that haemodilution could find a much application in neurosurgery than has been the case up to now.

Brain↗
PubMed1977

Disturbances in the blood-brain barrier and cerebral blood flow after rapid brain decompression in the cat.

The effect of sudden decompression of the brain on the blood-brain barrier and cerebral blood flow was studied in cats. The decompression experiments were performed on 9 cats which had been subjected to two hours of compression with an epidural balloon and on 10 cats subjected to four hours of balloon compression. In both experimental groups one could observe haemorrhages and disturbances in the blood-brain barrier in the cortex of the previously compressed hemisphere and in the basal nuclei. The extent of these changes depended on the duration of the epidural compression. At the same time, a decrease in cerebral blood flow, mainly in the brain cortex, was observed in both experimental groups.

Animals↗
PubMedDate not supplied

Effect of stable xenon in room air on regional cerebral blood flow and electroencephalogram in normal baboons.

Measurement of regional cerebral blood flow (rCBF) was performed in 6 healthy baboons during ventilation with 35% stable xenon in artificial air. rCBF was measured with the intraarterial xenon-133 method. EEG was recorded continuously. All CBF areas of interest over one hemisphere reacted in the same way. Mean flow increased during short-term exposure to stable xenon and decreased if stable xenon inhalation was continued for at least 24 minutes. EEG showed a decrease of alpha- and beta-wave patterns a short time after the start of stable xenon inhalation without further changes over the period when rCBF finally decreased. CO2 reactivity increased in most animals, and autoregulation to mild arterial hypotension was significantly impaired with increased flow. It is concluded that 35% stable xenon in artificial air increases rCBF after short-term exposure and decreases rCBF after longer exposure. EEG changes were noted after short-term exposure. rCBF and EEG recovered rapidly after the end of stable xenon inhalation.

Administration, Inhalation↗
PubMedDate not supplied

[Spread of pituitary adenomas beyond the sella].

Two cases of giant pituitary adenomas spreading extensively beyound the sella are described. In the 1st case death occurred 18 hours after the operation, in the 2nd case a good result was obtained by operation from subtemporal approach followed by 60Co radiotherapy. Control scintigraphic and angiographic examinations 11 months after treatment failed to demonstrate the signs which indicated extrasellar spread of adenoma before treatment.

Adenoma↗
PubMedDate not supplied

[Application of physiological data in evaluation of the intracranial volume-pressure interaction. I. An experimental study].

In experimental studies on cats the pressure and volume loadings corresponding to the physiological situations were used. The following tests were applied: central venous pressure increase, postural changes and increase of CO2 percentage in inspired gas mixture. It was found that the central venous pressure increase test is useful in the evaluation of CSF outflow routes, the postural change test examines the intracranial compensation and the elevation of CO2 level in inspired air tests the intracranial volume reserve.

Animals↗
PubMedDate not supplied

[Relation between resorption resistance of cerebrospinal fluid and the degree of intracranial pressure].

Changes in the CSF resorption resistance in relation to the value of the intracranial pressure have been assessed in 44 cats. Changes in the intracranial pressure have been produced with fluid infusions. Between 1 to 5 infusion tests with the rate 0.012-1.8 ml/min have been performed in each animal. A relationship between CSF resorption resistance and intracranial pressure has been found. With an increase in the intracranial pressure CSF resorption resistance increased to maximum value of 34 kPa/ml per minute (255.6 mm Hg/ml per minute) at pressure 2.96 +/- 0.69 kPa (22.2 +/- 5.2 mm Hg). At the intracranial pressure about 6.7 kPa (50 mm Hg) CSF resorption resistance rapidly decreased to the value of 13.9 kPa/ml per minute (104 mm Hg/ml per minute). Later, changes have been rather slight. It is possible, that the breaking point at 6.7 kPa corresponds to the mobilisation of all ways of CSF evacuation.

Absorption↗
PubMedDate not supplied

[Use of transcranial Doppler ultrasonography for evaluation of intracranial pressure].

Transcranial Doppler (TCD) studies are very useful for the evaluation of intracranial pressure changes. The most informative for the TCD increase diagnosis are the diastolic pressure decrease and increase of two computed indices: pulsatility index (PI) and resistance index (RI). Single measurements can be misleading and therefore, monitoring of neurosurgical intensive care patients is suggested. Additional information is provided by TCD studies in cerebral blood flow autoregulation tests. The usefulness of TCD in brain death diagnosis is discussed also.

Animals↗