RESUMO
PURPOSE: The purpose of this study is to evaluate a noninvasive device to assess intracranial pressure wave form in children with hydrocephalus. METHODS: A prospective and non-experimental descriptive-analytic study was performed. Fifty-six patients were enrolled in this study. They were divided in four groups: group A, children with clinically compensated hydrocephalus; B, surgically treated hydrocephalus; C, patients with acute intracranial hypertension due to hydrocephalus; and D, children without neurological disease (control). Data were collected through the installation of an extracranial deformation sensor, coupled to the children's scalp, which allowed registration of noninvasive intracranial pressure curves. Parameters obtained were analyzed: P2/P1 ratio, "classification P1 and P2 and P1 slope. RESULTS: P2/P1 index and "classification of P1 and P2" had a sensitivity of 80% and specificity of 100% for predicting intracranial hypertension. "P1 slope" presented no statistical difference. CONCLUSION: This study showed a useful and noninvasive method for monitoring intracranial pressure, which was able to indicate the intracranial hypertension in children with hydrocephalus and, thus, should be further investigated for clinical applications.
Assuntos
Hidrocefalia/complicações , Hidrocefalia/diagnóstico , Hipertensão Intracraniana/diagnóstico , Hipertensão Intracraniana/etiologia , Manometria/instrumentação , Crânio , Adolescente , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Pressão Intracraniana , MasculinoRESUMO
Intracranial pressure (ICP) monitoring is sometimes required in clinical pictures of stroke, as extensive intraparenchymal hematomas and intracranial bleeding may severely increase ICP, which can lead to irreversible conditions, such as dementia and cognitive derangement. ICP monitoring has been accepted as a procedure for the safe diagnosis of increased ICP, and for the treatment of intracranial hypertension in some diseases. In this work, we evaluated ICP behavior during the induction of an experimental model of autologous blood injection in rats, simulating a hemorrhagic stroke. Rats were subjected to stereotactic surgery for the implantation of a unilateral cannula into the left striatal region of the brain. Autologous blood was infused into the left striatal region with an automatic microinfusion pump. ICP monitoring was performed throughout the procedure of hemorrhagic stroke induction. Analyses consisted of short-time Fourier transform for ICP before and after stroke induction and the histological processing of the animals' brains. Short-time Fourier transform analysis demonstrated oscillations in the ICP frequency components throughout time after the microinjections compared with data before them. Histological analysis revealed neuropathological changes in the striatum in all microinjected animals.
Assuntos
Hemorragia Cerebral/fisiopatologia , Pressão Intracraniana/fisiologia , Acidente Vascular Cerebral/fisiopatologia , Animais , Hemorragia Cerebral/complicações , Hemorragia Cerebral/patologia , Corpo Estriado/patologia , Modelos Animais de Doenças , Análise de Fourier , Homeostase , Masculino , Monitorização Fisiológica , Ratos , Ratos Wistar , Acidente Vascular Cerebral/etiologia , Acidente Vascular Cerebral/patologiaRESUMO
Intracranial pressure (ICP) is a major neurological parameter in animals and humans. ICP is a function of the relationship between the contents of the cranium (brain parenchyma, cerebrospinal fluid, and blood) and the volume of the skull. Increased ICP can cause serious physiological effects or even death in patients who do not quickly receive proper care, which includes ICP monitoring. Epilepsies are a set of central nervous system disorders resulting from abnormal and excessive neuronal discharges, usually associated with hypersynchronism and/or hyperexcitability. Temporal lobe epilepsy (TLE) is one of the most common forms of epilepsy and is also refractory to medication. ICP characteristics of subjects with epilepsy have not been elucidated because there are few studies associating these two important neurological factors. In this work, an invasive (ICPi) and the new minimally invasive (ICPmi) methods were used to evaluate ICP features in rats with chronic epilepsy, induced by the experimental model of pilocarpine, capable of generating the main features of human TLE in these animals.
Assuntos
Epilepsia do Lobo Temporal/fisiopatologia , Hipocampo/diagnóstico por imagem , Pressão Intracraniana/fisiologia , Animais , Anticonvulsivantes/uso terapêutico , Encéfalo/diagnóstico por imagem , Encéfalo/patologia , Doença Crônica , Modelos Animais de Doenças , Epilepsia/induzido quimicamente , Epilepsia/tratamento farmacológico , Epilepsia/patologia , Epilepsia/fisiopatologia , Epilepsia do Lobo Temporal/induzido quimicamente , Epilepsia do Lobo Temporal/tratamento farmacológico , Epilepsia do Lobo Temporal/patologia , Hipocampo/patologia , Imageamento por Ressonância Magnética , Masculino , Agonistas Muscarínicos/toxicidade , Tamanho do Órgão , Pilocarpina/toxicidade , Ratos , Ratos Wistar , Tiopental/uso terapêuticoRESUMO
We consider a nontrivial one-species population dynamics model with finite and infinite carrying capacities. Time-dependent intrinsic and extrinsic growth rates are considered in these models. Through the model per capita growth rate we obtain a heuristic general procedure to generate scaling functions to collapse data into a simple linear behavior even if an extrinsic growth rate is included. With this data collapse, all the models studied become independent from the parameters and initial condition. Analytical solutions are found when time-dependent coefficients are considered. These solutions allow us to perceive nontrivial transitions between species extinction and survival and to calculate the transition's critical exponents. Considering an extrinsic growth rate as a cancer treatment, we show that the relevant quantity depends not only on the intensity of the treatment, but also on when the cancerous cell growth is maximum.