RESUMO
BACKGROUND: Intended open abdomen is an option in cases of trauma and non-trauma patients. Nevertheless, after primary closure, incisional hernia rate is high. We describe a novel method, called COmbined and MOdified Definitive Abdominal closure (COMODA), a delayed primary closure which prevents incisional hernia. METHODS: A negative pressure wound therapy system is combined with a condensed polytetrafluoroethylene (cPTFE) mesh. TRIAL REGISTRATION: ISRCTN72678033. RESULTS: Ten male patients with a median age of 68.8 (43-87) years were included. Primary closure rate was 100% per protocol. The median number of procedures per patient was 5.7 (5-9). Primary closure was obtained in 20.8 (10-32) days and median hospital stay was 36.3 (18-52) days. Only one patient developed incisional hernia during a median follow-up of 27 (8-60) months. CONCLUSION: COMODA method allows for a high rate of delayed primary closure. It is safe and decreases the risk for developing an incisional hernia. However, a large number of patients are needed to support this conclusion.
Assuntos
Hérnia Ventral/prevenção & controle , Hérnia Incisional/prevenção & controle , Tratamento de Ferimentos com Pressão Negativa , Técnicas de Abdome Aberto/métodos , Telas Cirúrgicas , Parede Abdominal/cirurgia , Adulto , Idoso , Idoso de 80 Anos ou mais , Hérnia Ventral/etiologia , Humanos , Hérnia Incisional/etiologia , Masculino , Metilmetacrilatos/administração & dosagem , Pessoa de Meia-Idade , Técnicas de Abdome Aberto/efeitos adversos , Politetrafluoretileno/administração & dosagem , Povidona/administração & dosagemRESUMO
OBJECTIVE: Priming-related hemodilution is the culprit behind excessive body water accumulation, postoperative coagulopathy and enhanced blood transfusion in infant cardiac surgery patients. In this retrospective, observational study, clinical data were analyzed to assess the effect of conventional ultrafiltration on allogenic blood transfusion and patient clinical outcome. METHODS: All infants with a bodyweight up to 10 kg who underwent consequent cardiac surgery in 2011 and 2012 were eligible for the audit. Seventy patients, operated in accordance with existing pediatric protocol, enrolled in the control group. The study group consisted of 55 patients who were operated employing conventional ultrafiltration during bypass and recently adjusted hematocrit targets. The following variables were primarily investigated: hematocrit and colloid osmotic pressure value, total volume of blood products transfused and duration of postoperative mechanical ventilation. Secondary outcome measures were: postoperative urine production, postoperative blood loss, length of stay at the intensive care unit and hospital stay. RESULTS: There were no significant differences between the groups in relation to demographics or hematological and cardiopulmonary bypass data. The ultrafiltration volume removed from circulation during bypass in the study group was 171 ± 99 ml. No significant difference between the groups was found with regard to the total allogenic blood transfusion (study group 216 ± 92 ml versus control group 191 ±93 ml; p = 0.136). All recorded clinical end points, duration of mechanical ventilation, duration of chest tube in situ, stay in ICU and stay in hospital, were similar between the groups. CONCLUSIONS: Routine use of conventional ultrafiltration during the cardiac surgery for patients with a bodyweight less than 10 kg was a safe technique that allowed us to achieve higher hematocrit levels at the end of the operation without additional transfusions of allogenic blood. On the other hand, ultrafiltration did not improve the clinical end points.
Assuntos
Transfusão de Sangue , Peso Corporal , Ponte Cardiopulmonar , Feminino , Hematócrito , Humanos , Lactente , Masculino , Estudos Retrospectivos , UltrafiltraçãoRESUMO
In sentences such as dogs cannot fly/bark, evaluation of the truth-value of the sentence is assumed to appear after the negation has been integrated into the sentence structure. Moreover negation processing and truth-value processing are considered effortful processes, whereas processing of the semantic relatedness of the words within sentences is thought to occur automatically. In the present study, modulation of event-related brain potentials (N400 and late positive potential, LPP) was investigated during an implicit task (silent listening) and active truth-value evaluation to test these theoretical assumptions and determine if truth-value evaluation will be modulated by the way participants processed the negated information implicitly prior to truth-value verification. Participants first listened to negated sentences and then evaluated these sentences for their truth-value in an active evaluation task. During passive listening, the LPP was generally more pronounced for targets in false negative (FN) than true negative (TN) sentences, indicating enhanced attention allocation to semantically-related but false targets. N400 modulation by truth-value (FN>TN) was observed in 11 out of 24 participants. However, during active evaluation, processing of semantically-unrelated but true targets (TN) elicited larger N400 and LPP amplitudes as well as a pronounced frontal negativity. This pattern was particularly prominent in those 11 individuals, whose N400 modulation during silent listening indicated that they were more sensitive to violations of the truth-value than to semantic priming effects. The results provide evidence for implicit truth-value processing during silent listening of negated sentences and for task dependence related to inter-individual differences in implicit negation processing.
Assuntos
Encéfalo/fisiologia , Enganação , Individualidade , Julgamento/fisiologia , Testes Neuropsicológicos , Percepção da Fala/fisiologia , Eletroencefalografia , Potenciais Evocados , Feminino , Humanos , Masculino , Tempo de Reação , Semântica , Adulto JovemRESUMO
BACKGROUND: Traumatized individuals and particularly post-traumatic stress disorder (PTSD) patients are characterized by memory disturbances that suggest altered memory control. The present study investigated the issue using an item method, directed forgetting (DF) paradigm in 51 civil war victims in Uganda. All participants had been exposed to severe traumatic stress and 26 additionally suffered from PTSD. METHOD: In an item cued, DF paradigm photographs were presented, each followed by an instruction to either remember or forget it. A recognition test for all initially presented photographs and thematically similar distracters followed. DF patterns were compared between the non-PTSD and the PTSD groups. Post-experimental ratings of picture valence and arousal were collected and correlated with DF. RESULTS: Results revealed DF, that is, reduced recognition for 'to-be-forgotten' items in the non-PTSD but not in the PTSD group. Moreover, in the non-PTSD, but not in the PTSD group, false alarms were reduced for 'to-be-remembered' items. Finally, DF was reduced in those participants who rated the pictures as more arousing, the PTSD group giving, on average, higher arousal ratings. CONCLUSIONS: Data indicate that DF is reduced in PTSD and that the reduction is related to stimulus arousal. Furthermore, individuals with PTSD are characterized by a more global encoding style than individuals without PTSD, reflected in a higher false alarm rate. In sum, traumatized individuals with (but not without) PTSD are impaired in their ability to selectively control episodic memory encoding. This impairment may contribute to clinical features of the disorder such as intrusions and flashbacks.
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Inibição Psicológica , Rememoração Mental/fisiologia , Refugiados/psicologia , Transtornos de Estresse Pós-Traumáticos/psicologia , Guerra , Adolescente , Adulto , Nível de Alerta/fisiologia , Estudos de Casos e Controles , Sinais (Psicologia) , Feminino , Humanos , Masculino , Testes Neuropsicológicos , Estimulação Luminosa , Reconhecimento Psicológico , Retenção Psicológica , Transtornos de Estresse Pós-Traumáticos/fisiopatologia , Estresse Psicológico/fisiopatologia , Estresse Psicológico/psicologia , Uganda , Adulto JovemRESUMO
BACKGROUND: Although mortality post-pancreaticoduodenectomy (PD) has decreased, morbidity rates continue to be high, ranging from 30% to 50%. Among complications, hemorrhage stands out; it is associated with high mortality and there is no standard management. The aim of the present study was to analyze the incidence, diagnosis, and treatment of hemorrhage post-cephalic PD at our center. METHODS: From January 2005 to December 2008, 107 PDs were performed. A retrospective review of characteristics of patients with postoperative hemorrhage was made from our prospective database. Demographic data, diagnosis, treatment (medical, laparotomy, interventional radiology), association with fistula (pancreatic or biliary), intra- or extraluminal hemorrhage, bleeding time (early or late), severity (moderate/severe), and mortality were analyzed. RESULTS: Eighteen patients (18/107; 16.82%) hemorrhaged after PD. Hemorrhage appeared early (< 24 h) in 4 of these 18 patients (22.2%), and it was severe in 13/18 (72%). Hemorrhage-related mortality was 11% (2/18) and hospital mortality was 22.2% (4/18). Arteriography was performed in 8/18 patients (44.4%) and was effective in 6/8 (75%); laparotomy was performed in 8/18 (44.4%). Re-bleeding occurred in 5 of these 18 patients after the first treatment (27.8%). An association between hemorrhage and fistula was observed. CONCLUSIONS: Hemorrhage after pancreatic resection must be considered a complication with relatively high mortality. Diagnosis should be established and treatment applied rapidly. Pancreatic and/or biliary fistulae were significantly associated with a higher risk of postoperative hemorrhage. Interventional radiology is a good therapeutic option.
Assuntos
Pancreaticoduodenectomia , Hemorragia Pós-Operatória , Idoso , Feminino , Seguimentos , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Hemorragia Pós-Operatória/diagnóstico , Hemorragia Pós-Operatória/epidemiologia , Hemorragia Pós-Operatória/terapia , Prognóstico , Recidiva , Estudos Retrospectivos , Fatores de RiscoRESUMO
Multispeckle diffusing-wave spectroscopy (DWS) is used to measure blood flow transients in the human visual cortex following stimulation by 7.5 Hz full-field and checkerboard flickering. The average decay time tau(d) characterizing the decay of the DWS autocorrelation function shows a biphasic behavior; within about 2 s after stimulation onset, tau(d) increases rapidly to about 6% above the baseline value. At later times, tau(d) slowly decreases and reaches a steady-state value about 5% below the baseline value after about 15 s. The initial increase of the DWS signal suggests a transient reduction of the cortical blood flow velocity shortly after stimulation onset. Measurements of this transient response at different positions over the primary visual cortex show a spatial pattern different from the one measured by electroencephalography.
Assuntos
Velocidade do Fluxo Sanguíneo/fisiologia , Mapeamento Encefálico/métodos , Circulação Cerebrovascular/fisiologia , Potenciais Evocados Visuais/fisiologia , Espectrofotometria Infravermelho/métodos , Córtex Visual/fisiologia , Adulto , Feminino , Humanos , Córtex Visual/irrigação sanguíneaRESUMO
INTRODUCTION: Results of surgical treatment for pancreatic and periampullary carcinoma have improved in recent years owing to several factors, particularly the concentration of these patients in specialised surgical units. MATERIAL AND METHODS: Retrospective-prospective comparative study of results in 2 groups of patients treated over 2 different periods of time and with different surgical policy: group A, which included 80 patients treated from 1982 to 1992 in a general surgery unit, and group B, which comprised 151 patients treated from 1998 to 2003 in a specialised hepato-biliary-pancreatic surgery unit. RESULTS: Surgical treatment in patients of groups A and B, respectively, was: resection in 20% and 53.6% and by-pass in 62.5% and 36.4%. Postoperative morbidity after resection was similar (75% vs 74.1%) but higher after by-pass in group B (41.8% vs 34%). Postoperative mortality after surgical resection and by-pass was 25% and 14.1%, respectively, for group A and 3.7% and 16.3%, respectively, for group B. Mean survival for all patients was 7.0 +/- 7.1 months for group A and 14.1 +/- 15.3 months for group B. Mean survival for patients with surgical resection was 11.8 +/- 9.8 months and 18.7 +/- 15.8 months for groups A and B, respectively. CONCLUSIONS: Pancreatic and periampullary carcinoma should be surgically treated in specialised pancreatic surgery units in order to offer the best outcome to patients.
Assuntos
Ampola Hepatopancreática , Neoplasias do Ducto Colédoco/cirurgia , Neoplasias Pancreáticas/cirurgia , Adulto , Idoso , Idoso de 80 Anos ou mais , Procedimentos Cirúrgicos do Sistema Digestório , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Análise de SobrevidaRESUMO
BACKGROUND: Schizophrenic patients exhibit more activity in the electroencephalographic delta and theta frequency range than do control subjects. Using magnetic source imaging (MSI) our study aimed to explore this phenomenon in the magnetoencephalogram (MEG), the distribution of its sources, and associations between symptom profiles and sources of low-frequency activity in the brain. METHODS: Whole-head MEG recordings were obtained from 28 schizophrenic patients and 20 healthy control subjects during a resting condition. The generators of the focal magnetic slow waves were located employing a single moving dipole model. Distributed or multiple delta and theta sources were captured by the minimum norm estimate. RESULTS: Both localization procedures showed slow wave activity to be enhanced in schizophrenic patients compared with control subjects. Focal slow wave activity differed most between groups in frontotemporal and in posterior regions. Slow wave activity was associated with symptom characteristics in that positive symptoms varied with frontal delta and theta activity. CONCLUSIONS: Results indicate that activity in low-frequency bands in schizophrenic patients exceeds the activity of control subjects in distinct areas, and that this focal clustering of neuromagnetic slow waves may be related to psychopathologic characteristics.
Assuntos
Mapeamento Encefálico , Esquizofrenia/fisiopatologia , Psicologia do Esquizofrênico , Adulto , Ritmo Delta , Feminino , Humanos , Magnetoencefalografia , Masculino , Ritmo TetaRESUMO
When two clicks are presented within 500 ms and the clicks are separated by several seconds, a typical finding is a suppression of the amplitude of the P50 component of the middle-latency auditory-evoked response. In the present study, we investigated whether only the P50 or also the earlier components Po, Na, Pa and Nb, and the exogenous components N100 and P200 exhibit an amplitude suppression to the second click. In addition, we studied the suppression behaviour of the auditory-evoked 40-Hz gamma-band response in the time and frequency domain. We found a significant amplitude suppression to the second click for all components of the auditory-evoked potential following Po, which was most pronounced at electrode Cz. When testing the successive peaks and troughs of the evoked 40-Hz gamma-band response in the time domain, we found a significant amplitude suppression for peaks and troughs with the same latency and polarity as the middle-latency components following Po, which was most pronounced at electrodes Fz and Cz. Consequently, the amplitude of the 40-Hz evoked gamma-band response in the frequency domain paralleled the findings of the time domain, with a significant amplitude suppression to the second tone, which was most pronounced at electrodes Fz and Cz. Results are discussed with reference to the early sensory-gating hypothesis.
Assuntos
Percepção Auditiva/fisiologia , Potenciais Evocados Auditivos/fisiologia , Estimulação Acústica , Adulto , Feminino , Humanos , Masculino , Inibição Neural/fisiologia , Tempo de Reação/fisiologiaRESUMO
BACKGROUND: A growing body of literature suggests that schizophrenic patients often do not show the normal brain hemispheric asymmetry. We have found this for simple tones presented to the right ear in a previous study. In this study we extended this investigation to left ear stimulation and verbal stimuli. METHODS: With a whole-head neuromagnetometer, contra- and ipsilateral auditory-evoked magnetic fields in response to tones (1000 Hz) and to the syllables ("ba") delivered to the left and right ears in separate runs were compared between schizophrenic patients (n = 17) and healthy control subjects (n = 15). RESULTS: In response to tones, all control subjects showed the expected asymmetry (contralateral predominance) of the auditory-evoked magnetic N100m (dipole moment). In the patient sample asymmetry was reversed following tones presented to the left ear in 47% and following tones to the right ear in 24%. In response to syllables, the asymmetry was similar between groups. In patients compared with control subjects the N100m was located more anterior without asymmetry between hemispheres. CONCLUSIONS: Results suggest that deviation from the normal functional lateralization in schizophrenia appears in a proportion of patients at a basic stage of auditory processing, but may be compensated for at higher levels such as the processing of syllables.
Assuntos
Córtex Cerebral/fisiopatologia , Potenciais Evocados Auditivos/fisiologia , Lateralidade Funcional/fisiologia , Magnetismo , Esquizofrenia/fisiopatologia , Estimulação Acústica , Adulto , Feminino , Humanos , Masculino , Análise e Desempenho de TarefasRESUMO
OBJECTIVES: High frequency oscillations have been suggested as a correlate of cognitive processes and have recently also been implicated in aberrant forms of information processing. The present study investigated whether magnetoencephalographic (MEG) gamma band activity (20-71 Hz) can serve as an index of cognitive processes in the absence of external stimulation and to what extent gamma activity differs between healthy people and schizophrenia patients. METHODS: The amount and topography of MEG power in the gamma band range was examined in 15 schizophrenia patients and 15 healthy comparison subjects while performing a complex mental arithmetic task and at rest. RESULTS: In healthy subjects a left frontal and left fronto-temporal increase in gamma power was observed during mental arithmetic. Schizophrenia patients either failed to display such a task effect (30-45 Hz) or had reversed lateralization with enhanced activity over right frontal and right fronto-temporal regions under cognitive demands (45-71 Hz). In the frequency band from 60 to 71 Hz patients showed less gamma at fronto-temporal, posterio-temporal and occipital sites irrespective of the task. CONCLUSIONS: These results indicate, first, that gamma topography can index cognitive activation in a very complex and purely internal task. Second, groups differed in the pattern of activation during the task, a result which may be consistent with working memory dysfunction in schizophrenia. Third, the general topographic difference between healthy subjects and patients is in line with the notion of abnormalities in the thalamocortical circuit in schizophrenia.
Assuntos
Encéfalo/fisiopatologia , Matemática , Esquizofrenia/fisiopatologia , Adulto , Mapeamento Encefálico , Lateralidade Funcional/fisiologia , Humanos , Magnetoencefalografia , Masculino , Análise e Desempenho de TarefasRESUMO
Intraventricular haemorrhage (IVH) occurs in up to 50% of patients with primary intracerebral haemorrhage and aneurysmal subarachnoid haemorrhage. It is a significant and independent contributor to mortality and morbidity in these intracranial haemorrhages. Using a model of isolated IVH, we assessed the morphological changes induced by intraventricular bleeding and investigated the effects of intraventricular fibrinolytic treatment following IVH. IVH was induced in 32 pigs by intraventricular infusion of 10 ml autologous blood along with thrombin. The treatment group received an intraventricular injection of 1.5 mg (1 mg/ml) tissue plasminogen activator (tPA) following the injection of blood. The placebo group received the same volume of normal saline. Morphological examinations of the brains were carried out 7 days and 6 weeks following IVH. The ventricles were incompletely filled with blood and significantly enlarged in the placebo group 7 days after the IVH. In contrast, no residual intraventricular clots were visible in the animals treated with tPA, and the diameters of the lateral ventricles had returned to normal within 7 days. Marked losses of the ependymal covering of the ventricular walls were found in the placebo-treated animals, while the ependymal layer was largely intact in the animals treated with tPA. No haemorrhages induced by tPA were observed. The results indicate that intraventricularly administered tPA significantly enhances the lysis of intraventricular blood clots, accelerates the resolution of acute posthaemorrhagic hydrocephalus, and preserves the integrity of the ependymal layer.
Assuntos
Hemorragia Cerebral/tratamento farmacológico , Hemorragia Cerebral/patologia , Ventrículos Cerebrais , Fibrinolíticos/administração & dosagem , Ativador de Plasminogênio Tecidual/administração & dosagem , Animais , Pressão Sanguínea , Hemorragia Cerebral/fisiopatologia , Ventrículos Cerebrais/patologia , Circulação Cerebrovascular , Fibrinolíticos/uso terapêutico , Injeções Intraventriculares , Pressão Intracraniana , Masculino , Proteínas Recombinantes/administração & dosagem , Proteínas Recombinantes/uso terapêutico , Suínos , Ativador de Plasminogênio Tecidual/uso terapêuticoRESUMO
Children have been shown to prefer faces rated as highly attractive by adults over faces rated as quite unattractive. We investigated to what extent this agreement holds not only for the general direction of preferences but for preference strengths as well. In a choice experiment, we presented 40 nine-year-old girls and their mothers and 40 twelve-year-old girls and their mothers with pairs of women's and girls' faces and asked the subjects to pick the face that appeared prettier to them. Preference frequencies and simple attractiveness scales derived from these preference frequencies by fitting the Bradley-Terry-Luce rule (Luce, D. R. (1959). Individual choice behavior: a theoretical analysis. New York: Wiley) were compared across subject groups. For the women's faces, we found no difference in preferences between nine-year-olds, twelve-year-olds, and adults, neither in direction nor in strength. For the girls' faces, we also found no major differences in preference direction, however, we did find reliable differences in preference strengths. To a considerable part these differences were due to the fact that the children showed less pronounced preferences between face stimuli than the adults. These results suggest a role of developmental factors in the perception of facial attractiveness.
Assuntos
Desenvolvimento Infantil , Face , Julgamento , Desejabilidade Social , Percepção Social , Adulto , Fatores Etários , Beleza , Criança , Feminino , HumanosRESUMO
In a randomized, double-blind, parallel group study, we compared the clinical efficacy of coumarin 90 mg/day (Group A) with 135 mg/day (Group B) in 77 women (age 35-65 years) with lymphedema of the upper limb secondary to surgery and irradiation for treatment of breast cancer. During 12 months of coumarin therapy, the arm volume of lymphedema and a clinical score (degree of arm edema, heaviness, hardness, and neuralgia/dysesthesia) were determined. In both groups, the volume of arm lymphedema decreased (14.9% in Group A and 13.2% in Group B) (N.S.), the overall clinical score improved (12.9 +/- 4.3 to 5.7 +/- 3.5 in Group A and from 11.7 +/- 3.7 to 4.7 +/- 3.9 in Group B) (N.S.), and the overall efficacy of coumarin was similarly good or excellent (71.9% in Group A and 68.6% in Group B) (N.S.). Only mild to moderate side effects of drug therapy were recorded. Coumarin prevents a spontaneous trend toward an increase in arm lymphedema after treatment of breast cancer, decreases the severity of local symptoms, and overall improves the quality of life. No difference was found between the apparent benefits of coumarin at 90 mg/day compared with 135 mg/day.
Assuntos
Neoplasias da Mama/terapia , Cumarínicos/administração & dosagem , Linfedema/tratamento farmacológico , Braço , Neoplasias da Mama/radioterapia , Neoplasias da Mama/cirurgia , Terapia Combinada/efeitos adversos , Cumarínicos/efeitos adversos , Cumarínicos/uso terapêutico , Relação Dose-Resposta a Droga , Método Duplo-Cego , Feminino , Humanos , Linfedema/etiologia , Pessoa de Meia-Idade , Resultado do TratamentoRESUMO
Twenty-four schizophrenia and 26 normal subjects were presented targets for fixation at +/-17.5 degrees and 0 degrees of visual angle. The manner in which stimuli were presented allowed us to evaluate for the presence of gaze-evoked and rebound drifts, and for frequency of saccades at both eccentric and central fixation. Schizophrenia patients and normal subjects had remarkably similar performance regardless of stimulus condition. These results suggest that the gaze-holding apparatus is functioning normally among schizophrenia patients, a finding that is not easily attributable to either medication effects and/or low statistical power. These data are another indication that schizophrenia patients have specific, not general, abnormalities of ocular motor control.
Assuntos
Fixação Ocular/fisiologia , Esquizofrenia/fisiopatologia , Adulto , Estudos de Casos e Controles , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Movimentos Sacádicos/fisiologiaRESUMO
BACKGROUND AND PURPOSE: Hemorrhagic ventricular dilatation (HVD) is a prominent feature of human intraventricular hemorrhage (IVH) and a strong indicator for poor outcome. We developed an IVH model to define the mechanisms responsible for HVD and to test the efficacy of intraventricular administration of tissue plasminogen activator (TPA) in the treatment of HVD. METHODS: Isolated IVH was produced in pigs by injecting 10 mL of blood simultaneously with thrombin into the right lateral ventricle. The treatment group received 1.5 mg of TPA after induction of IVH. Intraventricular blood volume and the volume of the lateral ventricles were assessed by CT after 90 minutes, 7 days, and 42 days. Intracranial pressure, the pressure-volume index, and the resistance to outflow of cerebrospinal fluid (R(out)) were measured 30 minutes and 7 days after IVH. RESULTS: After IVH, the volume of the lateral ventricles increased from 1.98 +/- 0.69 to 6.43 +/- 1.23 mL (P < .001). There was a linear relationship between ventricular and clot volume (P = .014). Initially, R(out) increased from 24.34 +/- 7.13 to 63.56 +/- 64.91 mm Hg/mL per minute (P < .001). After 7 days, restoration of normal cerebrospinal fluid circulation occurred, but the ventricles were still significantly enlarged (5.24 +/- 1.76 mL, P < .001) and filled with blood. Within 6 weeks, ventricular volume had returned to normal values, paralleled by complete clot resolution. Intraventricular administration of TPA significantly accelerated clot clearance and restoration of normal ventricle volume. CONCLUSIONS: These results suggest that intraventricular bleeding may cause impairment of cerebrospinal fluid circulation but that the mass effect of clots distending the ventricle walls is the most important mechanism responsible for HVD. This model closely imitates several prominent features of human IVH and may therefore be a useful tool for preclinical assessment of the efficacy and safety of treatment with TPA.