MARCELO DE LIMA OLIVEIRA
Projetos de Pesquisa
Unidades Organizacionais
LIM/26 - Laboratório de Pesquisa em Cirurgia Experimental, Hospital das Clínicas, Faculdade de Medicina
8 resultados
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Agora exibindo 1 - 8 de 8
- Experimental rnodel of intracranial hypertension with continuous multiparametric monitoring in swine(2013) ANDRADE, Almir Ferreira de; SOARES, Matheus Schmidt; PATRIOTA, Gustavo Cartaxo; BELON, Alessandro Rodrigo; PAIVA, Wellingson Silva; BOR-SENG-SHU, Edson; OLIVEIRA, Marcelo de Lima; NASCIMENTO, Clarissa Nobrega; NOLETO, Gustavo Sousa; ALVES JUNIOR, Aderaldo Costa; FIGUEIREDO, Eberval Gadelha; OTOCH, Jose Pinhata; TEIXEIRA, Manoel JacobsenObjective: Intracranial hypertension (IN) develops in approximately 50% of all patients with severe traumatic brain injury (TBI). Therefore, it is very important to identify a suitable animal model to study and understand the pathophysiology of refractory IH to develop effective treatments. Methods: We describe a new experimental porcine model designed to simulate expansive brain hematoma causing IH. Under anesthesia, was simulated with a balloon insufflation. The IH variables were measured with intracranial pressure (ICP) parenchymal monitoring, epidural, cerebral oximetry, and transcranial Doppler (TCD). Results: None of the animals died during the experiment. The ICP epidural showed a slower rise compared with parenchymal ICP. We found a correlation between ICP and cerebral oximetry. Conclusion: The model described here seems useful to understand some of the pathophysiological characteristics of acute IH.
- Evaluation of cerebral hemodynamics by transcranial Doppler ultrasonography and its correlation with intracranial pressure in an animal model of intracranial hypertension(2022) SOARES, Matheus Schmidt; ANDRADE, Almir Ferreira de; BRASIL, Sergio; DE-LIMA-OLIVEIRA, Marcelo; BELON, Alessandro Rodrigo; BOR-SENG-SHU, Edson; NOGUEIRA, Ricardo de Carvalho; GODOY, Daniel Agustin; PAIVA, Wellingson SilvaBackground: Transcranial Doppler has been tested in the evaluation of cerebral hemodynamics as a non-invasive assessment of intracranial pressure (ICP), but there is controversy in the literature about its actual benefit and usefulness in this situation. Objective: To investigate cerebral blood flow assessed by Doppler technique and correlate with the variations of the ICP in the acute phase of intracranial hypertension in an animal model. Methods:An experimental animal model of intracranial hypertension was used. The experiment consisted of two groups of animals in which intracranial balloons were implanted and inflated with 4 mL (A) and 7 mL (B) for controlled simulation of different volumes of hematoma. The values of ICP and Doppler parameters (systolic [FVs], diastolic [FVd], and mean [FVm] cerebral blood flow velocities and pulsatility index [PI]) were collected during the entire procedure (before and during hematoma simulations and venous hypertonic saline infusion intervention). Comparisons between Doppler parameters and ICP monitoring were performed. Results: Twenty pigs were studied, 10 in group A and 10 in group B. A significant correlation between PI and ICP was obtained, especially shortly after abrupt elevation of ICP. There was no correlation between ICP and FVs, FVd or FVm separately. There was also no significant change in ICP after intravenous infusion of hypertonic saline solution. Conclusions:These results demonstrate the potential of PI as a parameter for the evaluation of patients with suspected ICP elevation.
- Estimation of intracranial pressure by ultrasound of the optic nerve sheath in an animal model of intracranial hypertension(2021) JENG, Brasil Chian Ping; ANDRADE, Almir Ferreira de; BRASIL, Sergio; BOR-SENG-SHU, Edson; BELON, Alessandro Rodrigo; ROBERTIS, Maira; DE-LIMA-OLIVEIRA, Marcelo; RUBIANO, Andres Mariano; GODOY, Daniel Agustin; TEIXEIRA, Manoel Jacobsen; PAIVA, Wellingson SilvaBackground: Ultrasound of the optic nerve sheath diameter (ONSD) has been used as a non-invasive and cost-effective bedside alternative to invasive intracranial pressure (ICP) monitoring. However, ONSD time-lapse behavior in intracranial hypertension (ICH) and its relief by means of either saline infusion or surgery are still unknown. The objective of this study was to correlate intracranial pressure (ICP) and ultrasonography of the optic nerve sheath (ONS) in an experimental animal model of ICH and deter-mine the interval needed for ONSD to return to baseline levels. Methods: An experimental study was conducted on 30 pigs. ONSD was evaluated by ultrasound at differ-ent ICPs generated by intracranial balloon inflation, saline infusion, and balloon deflation, and measured using an intraventricular catheter. Results: All variables obtained by ONS ultrasonography such as left, right, and average ONSD (AON) were statistically significant to estimate the ICP value. ONSD changed immediately after balloon inflation and returned to baseline after an average delay of 30 min after balloon deflation (p = 0.016). No statistical sig-nificance was observed in the ICP and ONSD values with hypertonic saline infusion. In this swine model, ICP and ONSD showed linear correlation and ICP could be estimated using the formula:-80.5 + 238.2 x AON. Conclusion: In the present study, ultrasound to measure ONSD showed a linear correlation with ICP, although a short delay in returning to baseline levels was observed in the case of sudden ICH relief.
- The influence of intracranial hypertension on static cerebral autoregulation(2020) DE-LIMA-OLIVEIRA, Marcelo; FERREIRA, Almir Andrade; BELON, Alessandro Rodrigo; SALINET, Angela Macedo; NOGUEIRA, Ricardo Carvalho; PING, Brasil Chian; PAIVA, Wellingson Silva; TEIXEIRA, Manoel Jacobsen; BOR-SENG-SHU, EdsonObjectives To analyze the influences of mild and severe intracranial hypertension on cerebral autoregulation (CA). Patients and Methods Duroc piglets were monitored with an intracranial pressure (ICP) catheter. Intracranial hypertension was induced via infusion of 4 or 7 ml of saline solution by a bladder catheter that was inserted into the parietal lobe. The static cerebral autoregulation (sCA) index was evaluated via cerebral blood flow velocities (CBFv). Piglets with ICPs <= 25 and > 25 mmHg were considered as group 1 and 2, respectively. Continuous variables were evaluated using the Kolmogorov-Smirnov goodness-of-fit test. The main parameters were collected before and after ICH induction and compared using two-factor mixed-design ANOVAs with the factor of experimental group (mild and severe ICH). Results In group 1 (ICP <= 25 mmHg), there were significant differences in sCA (p= .01) and ICP (p= .0002) between the basal and balloon inflation conditions. In group 2 (ICP > 25 mmHg), there were significant differences in CBFv (p= .0072), the sCA index (p= .0001) and ICP (p= .00001) between the basal and balloon inflation conditions. Conclusion We conclude that ICH may have a direct effect on mild and severe sCA.
- Assessing ultrasonographic optic nerve sheath diameter in animal model with anesthesia regimens(2022) AZEVEDO, Maira de Robertis; DE-LIMA-OLIVEIRA, Marcelo; BELON, Alessandro Rodrigo; BRASIL, Sergio; TEIXEIRA, Manoel Jacobsen; PAIVA, Wellingson Silva; BOR-SENG-SHU, EdsonPurpose: To determine the normal optical nerve sheath (ONS) diameter ultrasonography (ONSUS) and evaluate the possible effects of drugs on ONS diameter during anesthetic induction in healthy pigs. Methods: Healthy piglets were divided into three groups: a control group, that received xylazine and ketamine (X/K); other that received xylazine, ketamine and propofol (X/K/P); and a third group that received xylazine, ketamine, and thiopental (X/K/T). The sheath diameter was assessed by ultrasonography calculating the average of three measurements of each eye from the left and right sides. Results: 118 animals were anesthetized (49 X/K 33 X/K/P and 39 X/K/T). Mean ONS sizes on both sides in each group were 0.394 +/- 0.048 (X/K), 0.407 +/- 0.029 (X/K/P) and 0.378 +/- 0.042 cm (X/K/T) (medians of 0.400, 0.405 and 0.389, respectively). The ONS diameter varied from 0.287-0.512 cm (mean of 0.302 +/- 0.039 cm). For group X/K, the mean diameter was 0.394 +/- 0.048 cm. Significant differences in ONS sizes between the groups P and T (X/K/P > X/K/T, p = 0.003) were found. No statistically significant differences were detected when other groups were compared (X/K = X/K/P, p = 0.302; X/K = X/K/T, p = 0.294). Conclusion: Sedation with thiopental lead to significative ONS diameter reduction in comparison with propofol. ONSUS may be useful to evaluate responses to thiopental administration.
- The Effects of Induction and Treatment of Intracranial Hypertension on Cerebral Autoregulation: An Experimental Study(2018) OLIVEIRA, Marcelo de Lima; SALINET, Angela Macedo; NOGUEIRA, Ricardo de Carvalho; BELON, Alessandro Rodrigo; PAIVA, Wellingson Silva; JENG, Brasil Chian Ping; TEIXEIRA, Manoel Jacobsen; BOR-SENG-SHU, EdsonBackground. This study aimed to analyse cerebral autoregulation (CA) during induction and treatment of intracranial hypertension (ICH) in an experimental model. Materials and Methods. Landrace and Duroc piglets were divided into mild and severe ICH groups. Four or seven millilitres of saline solution was infused into paediatric bladder catheter inserted in the parietal lobe (balloon inflation). After 1.5 h, a 3% saline solution was infused via venous catheter, and 30 min later, the bladder catheter balloon was deflated (surgery). The cerebral static autoregulation (sCA) index was evaluated using cerebral blood flow velocities (CBFV) obtained with Doppler ultrasound. Results. Balloon inflation increased ICP in both groups. The severe ICH group showed significantly lower sCA index values (p=0.001, ANOVA) after balloon inflation (ICH induction) and a higher sCA index after saline injection (p=0.02) and after surgery (p=0.04). ICP and the sCA index were inversely correlated (r=-0.68 and p<0.05). CPP and the sCA index were directly correlated (r=0.74 and p<0.05). Conclusion. ICH was associated with local balloon expansion, which triggered CA impairment, particularly in the severe ICH group. Moreover, ICP-reducing treatments were associated with improved CA in subjects with severe ICH.
conferenceObject INTRACRANIAL HYPERTENSION MODEL IN PIGS: ASSESSMENT WITH TRANSCRANIAL DOPPLER AND INTRACRANIAL PRESSURE MONITORING(2014) ANDRADE, Almir Ferreira de; MATHEUS, S.; PATRIOTA, Gustavo C.; BELON, Alessandro; PAIVA, Wellingson S.; JENG, Brasil P.; BOR-SENG-SHU, Edson; OLIVEIRA, Marcelo; NASCIMENTO, Clarissa; AMORIM, Robson; FIGUEIREDO, Eberval G.; OTOCH, Jose P.; TEIXEIRA, Manoel J.conferenceObject VARIATION OF OPTICAL NERVE SHEATH DIAMETER DURING ANESTHESIA IN EXPERIMENTAL MODEL WITHOUT INTRACRANIAL HYPERTENSION(2017) BRASIL, S.; DE-LIMA-OLIVEIRA, M.; PAIVA, W.; BOSSE, E.; BOR-SENG-SHU, E.; EVANGELISTA, M.; TEIXEIRA, M. Jacobsen; BELON, A.; AZEVEDO, M.