The Retrograde Ventriculosinusal Shunt in an Animal Experimental Model of Hydrocephalus.

Currently, hydrocephalus treatment is performed mainly with ventriculoperitoneal shunting. This experimental study aims at assessing whether the experimental model of hydrocephalus in dogs is applicable to the laboratory study of the retrograde ventriculosinusal shunt (RVSS). Four mongrel dogs were assessed.

Local and remote ischemic preconditioning protect against intestinal ischemic/reperfusion injury after supraceliac aortic clamping.

Objectives: This study tests the hypothesis that local or remote ischemic preconditioning may protect the intestinal mucosa against ischemia and reperfusion injuries resulting from temporary supraceliac aortic clamping.

Methods: Twenty-eight Wistar rats were divided into four groups: the sham surgery group, the supraceliac aortic occlusion group, the local ischemic preconditioning prior to supraceliac aortic occlusion group, and the remote ischemic preconditioning prior to supraceliac aortic occlusion group. Tissue samples from the small bowel were used for quantitative morphometric analysis of mucosal injury, and blood samples were collected for laboratory analyses.

Intraportal versus Systemic Pentoxifylline Infusion after Normothermic Liver Ischemia: Effects on Regional Blood Flow Redistribution and Hepatic Ischemia-Reperfusion Injury.

Pentoxifylline (PTX) has been shown to have beneficial effects on microcirculatory blood flow. In this study we evaluate the potential hemodynamic and metabolic benefits of PTX during hepatic ischemia. We also test the hypothesis that portal PTX infusion can minimize the I/R injury when compared to systemic infusion.

Endoscopy Ultra- Sonography -guided biliary drainage in the surgical -endoscopy era.

Background: US-guided hepatico - gastrostomy, choledocho-duodenostomy and choledocho-antrostomy are advanced procedures on biliary and pancreatic endoscopy and together make up the echo-guided biliary drainage. Hepatico - gastrostomy is indicated in cases of hiliar obstruction, while the procedure of choice is choledocho - duodenostomy in distal lesions. Both procedures must be done only after unsuccessful ERCP.

Replacement of fentanyl infusion by enteral methadone decreases the weaning time from mechanical ventilation: a randomized controlled trial.

Introduction: Patients undergoing mechanical ventilation (MV) are frequently administered prolonged and/or high doses of opioids which when removed can cause a withdrawal syndrome and difficulty in weaning from MV. We tested the hypothesis that the introduction of enteral methadone during weaning from sedation and analgesia in critically ill adult patients on MV would decrease the weaning time from MV.

Methods: A double-blind randomized controlled trial was conducted in the adult intensive care units (ICUs) of four general hospitals in Brazil.

N-acetylcysteine (NAC) protects against acute kidney injury (AKI) following prolonged pneumoperitoneum in the rat.

Background: Acute kidney injury (AKI) following prolonged laparoscopy is a documented phenomenon. Carbon dioxide pneumoperitoneum induces oxidative stress. Previous experimental studies have shown that the antioxidant, N-acetylcysteine, protects the rat from AKI following ischemia-reperfusion.

The effects of low and high tidal volume and pentoxifylline on intestinal blood flow and leukocyte-endothelial interactions in mechanically ventilated rats.

Background: The combination of high PEEP and low tidal volume (V(T)) decreases some risks of mechanical ventilation, including pulmonary overdistention, damage due to cyclic opening and closing of the alveoli, and inflammatory responses that can lead to multiple-organ dysfunction. We hypothesized that high V(T) and high PEEP induce mesenteric microcirculatory disturbances and that those disturbances would be attenuated by pentoxifylline, which is anti-inflammatory.

Methods: We anesthetized (isoflurane 1.

Entrapped victims in motor vehicle collisions: characteristics and prehospital care in the city of São Paulo, Brazil.

Objective: To examine the severity of trauma in entrapped victims and to identify risk factors for mortality and morbidity.

Introduction: Triage and rapid assessment of trauma severity is essential to provide the needed resources during prehospital and hospital phases and for outcome prediction. It is expected that entrapped victims will have greater severity of trauma and mortality than non-entrapped subjects.

Microcirculatory effects of local and remote ischemic preconditioning in supraceliac aortic clamping.

Introduction: Supraceliac aortic clamping in major vascular procedures promotes splanchnic ischemia and reperfusion (I/R) injury that may induce endothelial dysfunction, widespread inflammation, multiorgan dysfunction, and death. We tested the hypothesis that local or remote ischemic preconditioning (IPC) may be protective against injury after supraceliac aortic clamping through the modulation of mesenteric leukocyte-endothelial interactions, as evaluated with intravital microscopy and expression of adhesion molecules.

Methods: Fifty-six male Wistar rats (weight, 190 to 250 g), were divided into four groups of 14 rats each: control-sham surgery without aortic occlusion; I/R through supraceliac aortic occlusion for 20 minutes, followed by 120 minutes of reperfusion; local IPC through supraceliac aortic occlusion for two cycles of 5 minutes of ischemia and 5 minutes of reperfusion, followed by the same protocol of the IR group; remote IPC through infrarenal aortic occlusion for two cycles of 10 minutes of ischemia and 10 minutes of reperfusion, followed by the same protocol of the IR group.

Fluid resuscitation with isotonic or hypertonic saline solution avoids intraneural calcium influx after traumatic brain injury associated with hemorrhagic shock.

Background: Calcium is one of the triggers involved in ischemic neuronal death. Because hypotension is a strong predictor of outcome in traumatic brain injury (TBI), we tested the hypothesis that early fluid resuscitation blunts calcium influx in hemorrhagic shock associated to TBI.

Methods: Fifteen ketamine-halothane anesthetized mongrel dogs (18.

Vasodilation increases pulse pressure variation, mimicking hypovolemic status in rabbits.

Objective: To test the hypothesis that pulse pressure respiratory variation (PPV) amplification, observed in hypovolemia, can also be observed during sodium nitroprusside (SNP)-induced vasodilation.

Introduction: PPV is largely used for early identification of cardiac responsiveness, especially when hypovolemia is suspected. PPV results from respiratory variation in transpulmonary blood flow and reflects the left ventricular preload variations during respiratory cycles.

Fluid replacement with hypertonic or isotonic solutions guided by mixed venous oxygen saturation in experimental hypodynamic sepsis.

Background: Splanchnic perfusion is prone to early injury and persists despite normalization of global hemodynamic variables in sepsis. Volume replacement guided by oxygen derived variables has been recommended in the management of septic patients. Our hypothesis was that a hypertonic isoncotic solution would improve the benefits of crystalloids replacement guided by mixed venous oxygen saturation.

Pulse oximetry wave variation as a noninvasive tool to assess volume status in cardiac surgery.

Objective: To compare variations of plethysmographic wave amplitude (DeltaPpleth) and to determine the percent difference between inspiratory and expiratory pulse pressure (DeltaPp) cutoff values for volume responsiveness in a homogenous population of postoperative cardiac surgery patients.

Introduction: Intra-thoracic pressure variations interfere with stroke volume variation. Pulse pressure variations through arterial lines during mechanical ventilation have been recommended for the estimation of fluid responsiveness.

Estradiol's salutary effects on keratinocytes following trauma-hemorrhage are mediated by estrogen receptor (ER)-alpha and ER-beta.

Although administration of 17beta-estradiol (estrogen) following trauma-hemorrhage attenuates the elevation of cytokine production and mitogen-activated protein kinase (MAPK) activation in epidermal keratinocytes, whether the salutary effects of estrogen are mediated by estrogen receptor (ER)-alpha or ER-beta is not known. To determine which estrogen receptor is the mediator, we subjected C3H/HeN male mice to trauma-hemorrhage (2-cm midline laparotomy and bleeding of the animals to a mean blood pressure of 35 mmHg and maintaining that pressure for 90 min) followed by resuscitation with Ringer's lactate (four times the shed blood volume). At the middle of resuscitation we subcutaneously injected ER-alpha agonist propyl pyrazole triol (PPT; 5 microg/kg), ER-beta agonist diarylpropionitrile (DPN; 5 microg/kg), estrogen (50 microg/kg), or ER antagonist ICI 182,780 (150 microg/kg).

Experimental models of sepsis and their clinical relevance.

Sepsis remains a major cause of morbidity and mortality mainly because of sepsis-induced multiple organ dysfunction. In contrast to preclinical studies, most clinical trials of promising new treatment strategies for sepsis have failed to demonstrate efficacy. Although many reasons could account for this discrepancy, the misinterpretation of preclinical data obtained from experimental studies and especially the use of animal models that do not adequately mimic human sepsis may have been contributing factors.

Quality of life and neuropsychological changes in mild head trauma. Late analysis and correlation with S100B protein and cranial CT scan performed at hospital admission.

Introduction: mild head trauma (MHT) is defined as a transient neurological deficit after trauma with a history of impairment or loss of consciousness lasting less than 15 min and/or posttraumatic amnesia, and a Glasgow Coma Scale between 13 and 15 on hospital admission. We evaluated 50 MHT patients 18 months after the trauma, addressing signs and symptoms of post-concussion syndrome, quality of life and the presence of anxiety and depression. We correlate those findings with the S100B protein levels and cranial CT scan performed at hospital admission after the trauma.

In vivo observation of mesenteric leukocyte-endothelial interactions after cecal ligation/puncture and surgical sepsis source control.

Purpose: Cecal ligation and puncture (CLP) has been used as a useful model for the induction of polymicrobial sepsis. Necrotic tissue resection and peritoneal lavage (REL) are the surgical procedures for controlling perforated appendicitis. The aim of this study was to evaluate leukocyte-endothelial interactions in the rat mesentery in vivo after CLP and REL.

Pulse pressure respiratory variation as an early marker of cardiac output fall in experimental hemorrhagic shock.

Pulse pressure (DeltaPp) and systolic pressure (DeltaPs) variations have been recommended as predictors of fluid responsiveness in critically ill patients. We hypothesized that changes in DeltaPp and DeltaPs parallel alterations in stroke volume (SV) and cardiac output (CO) during hemorrhage, shock, and resuscitation. In anesthetized and mechanically ventilated mongrel dogs, a graded hemorrhage (20 mL/min) was induced to a target mean arterial pressure (MAP) of 40 mm Hg, which was maintained for additional 30 min.

Low hematocrit impairs gastric mucosal CO2 removal during experimental severe normovolemic hemodilution.

Objective: The net effects of acute normovolemic hemodilution with different hemoglobin levels on splanchnic perfusion have not been elucidated. The hypothesis that during moderate and severe normovolemic hemodilution, systemic and splanchnic hemodynamic parameters, oxygen-derived variables, and biochemical markers of anaerobic metabolism do not reflect the adequacy of gastric mucosa, was tested in this study.

Methods: Twenty one anesthetized mongrel dogs (16 +/- 1 kg) were randomized to controls (CT, n = 7, no hemodilution), moderate hemodilution (hematocrit 2 5% +/- 3%, n = 7) or severe hemodilution (severe hemodilution, hematocrit 15% +/- 3%, n = 7), through an isovolemic exchange of whole blood and 6% hydroxyethyl starch, at a 20 mL/min rate, to the target hematocrit.

Leukocyte-endothelium interactions after hemorrhagic shock/reperfusion and cecal ligation/puncture: an intravital microscopic study in rat mesentery.

Hemorrhagic shock/reperfusion (HS/R) followed by sepsis triggers systemic microcirculatory disturbances that may induce multiple organ failure. The present study evaluated the effects of HS/R and cecal ligation and puncture, followed by necrotic cecal resection/peritoneal lavage (REL) on leukocyte-endothelium interactions at the mesentery. Eighty-one anesthetized Wistar rats (200-250 g) were randomly assigned to a first injury: (1) control-HS-no hemorrhagic shock/no reperfusion group, (2) HS/blood-HS/R with 25% shed blood, and (3) HS/blood + LR-HS/R with 25% of the shed blood + lactated Ringer's solution, 3x shed blood volume.

Variation in amplitude of central venous pressure curve induced by respiration is a useful tool to reveal fluid responsiveness in postcardiac surgery patients.

We tested the hypothesis that the dynamic evaluation of central venous pressure (CVP) amplitude could be a reliable predictor of fluid responsiveness in patients under mechanical ventilation, similar to the variation of arterial pulse pressure (DeltaPp). Thirty postcardiac surgery patients, under mechanical ventilation, were evaluated. The percentual difference between inspiratory (Ppins) and expiratory pulse pressure (Ppins) was so calculated: DeltaPp (%) = 100 x (Ppins - Ppexp)/[(Ppins + Ppexp)/2].

Ischemic preconditioning prevents apoptotic cell death and necrosis in early and intermediate phases of liver ischemia-reperfusion injury in rats.

Ischemic preconditioning (IPC) may be useful in attenuating the hepatic ischemia reperfusion (IR) syndrome by means of improving cell resistance to anoxia and reoxygenation and preventing cell death. Since there are insufficient data available regarding the chronology of preconditioning effects, we investigated the role of IPC, to test the hypothesis that liver protection would occur during the early and intermediate phases of the reperfusion period. Wistar rats (n = 72) were randomly assigned into six experimental groups, 12 animals each.

[Initial evaluation of systemic and regional pCO2 gradients as markers of mesenteric hypoperfusion].

Background: Mesenteric ischemia is a life-threatening emergency with a mortality rates still ranging between 60% and 100%.

Aim: To evaluate the systemic and regional pCO2 gradients changes induced by mesenteric ischemia-reperfusion injury. In addition, we sought to determine if other systemic marker of splanchnic hypoperfusion could detect the initial changes in intestinal mucosal microcirculation after superior mesenteric artery occlusion.