Search Results

You are looking at 1 - 10 of 51 items for :

  • By Author: Marmarou, Anthony x
Clear All
Full access

Anthony Marmarou

Object

Brain edema resulting from traumatic brain injury (TBI) or ischemia if uncontrolled exhausts volume reserve and leads to raised intracranial pressure and brain herniation. The basic types of edema—vasogenic and cytotoxic—were classified 50 years ago, and their definitions remain intact.

Methods

In this paper the author provides a review of progress over the past several decades in understanding the pathophysiology of the edematous process and the success and failures of treatment. Recent progress focused on those manuscripts that were published within the past 5 years.

Results

Perhaps the most exciting new findings that speak to both the control of production and resolution of edema in both trauma and ischemia are the recent studies that have focused on the newly described “water channels” or aquaporins. Other important findings relate to the predominance of cellular edema in TBI.

Conclusions

Significant new findings have been made in understanding the pathophysiology of brain edema; however, less progress has been made in treatment. Aquaporin water channels offer hope for modulating and abating the devastating effects of fulminating brain edema in trauma and stroke.

Restricted access

Kenneth Shapiro and Anthony Marmarou

often fatal, rises in pressure represents a critical shortcoming. To circumvent this deficiency, techniques using bolus manipulation of fluid 10 and, more recently, pulse wave analysis 1 have been developed. These techniques can be used to assess neural axis compliance in order to identify patients at risk of sudden increases of ICP. One of these techniques, the pressure-volume index (PVI), which utilizes bolus manipulation of cerebrospinal fluid (CSF), has been developed in this laboratory. The application of PVI testing to the care of head-injured children will be

Restricted access

Gerrit J. Bouma, J. Paul Muizelaar, Kuniaki Bandoh and Anthony Marmarou

I t is customary to explain raised intracranial pressure (ICP) after head trauma in terms of volume increases within the intracranial compartment, be it caused by hematoma, cerebrospinal fluid (CSF), tissue water (edema), or cerebral blood volume (CBV). The extent to which such volume changes will translate into changes in pressure depends on the compliance or volume-buffering capacity of the system. Compliance of the craniospinal axis, defined as the change in CSF volume per unit change in pressure, is not constant but increases as pressure rises. 25 The

Restricted access

Angelo L. Maset, Anthony Marmarou, John D. Ward, Sung Choi, Harry A. Lutz, Danny Brooks, Richard J. Moulton, Antonio DeSalles, J. Paul Muizelaar, Hope Turner and Harold F. Young

S ince the introduction of intracranial pressure (ICP) measurement by Guillaume and Janny 4 and Lundberg, 13 ICP monitoring has been a useful adjunct in the management of patients with brain injury. Clinical studies reported during the last decade have described the close correlation between intracranial hypertension and outcome. 2, 7, 9, 16, 17, 20–22 Other reports have emphasized the neurological deterioration resulting from secondary insult to the brain induced by depletion of volume-buffering capacity and development of high ICP. As a result of these

Restricted access

Katsuji Shima and Anthony Marmarou

T he fluid-percussion model has been used widely in the production of experimental head injury. Investigators using this model have made substantial contributions to the body of knowledge elucidating mechanisms of brain trauma. In recent studies, conducted at high injury levels, we observed that the edema resulting from severe experimental brain injury in animals that died shortly after injury was maximal in brain-stem areas. 22 We hypothesized that animals subjected to high levels of fluid percussion, which involves significant fluid volume injection into

Restricted access

Panos P. Fatouros and Anthony Marmarou

error in f w by this noninvasive method is ± 0.5%. In practice, other sources of error such as head movement and partial volume artifacts might further reduce the accuracy of the f w estimate. Comparison of MR Imaging and Gravimetric Values The f w expressed in grams of H 2 O per gram of tissue derived from the gravimetric measures and the corresponding values obtained from MR images are plotted in Fig. 1 . The straight line, representing the best linear fit, is described by the equation f w (MR image) = 1.716 + 0.9847f w (grav), (r 2 = 0.976). The mean absolute

Restricted access

Michael F. Stiefel and Anthony Marmarou

have indicated an elevation of [Na + ] e at the onset of ischemia. 9, 16 We posit that this initial rise of [Na + ] e is due to a rapid reduction in ECS volume. The ECS, which normally comprises 20% of total brain volume, decreases by 20% during the initial stages of ischemia. 11, 13, 16, 23 Given that Na + accumulation at the onset of ischemia is approximately 2 to 3%, it is conceivable that this rise is due solely to a reduction in ECS volume. The overaccumulation of [Na + ] e during the initial stages of reperfusion may result from enhanced ion transport

Restricted access

Kazuo Yoshida and Anthony Marmarou

brain pH, phosphocreatine (PCr), and inorganic phosphate (Pi) were obtained and samples of arterial and venous blood were withdrawn for measurement of arteriovenous differences of lactate. The ventilator was adjusted to deliver a tidal volume of 15 cc/kg at a rate of 10 to 12 breaths/min to maintain arterial PaCO 2 at 35 ± 5 mm Hg and PaCO 2 above 100 mm Hg; bicarbonate was added to correct any base deficit at this stage in the experiment. After control measurements of energy metabolism were made, the animals were subjected to a left-sided fluid-percussion trauma

Restricted access

Kenji Ohata and Anthony Marmarou

(D) photographs of the same section. The distribution of fluorescence is similar to that of Fig. 3B . The margin of the fluorescent area is well demarcated. Two fluorescent lines were observed running from the fluorescence center to the cortical surface (arrows) . In the group of sham-treated animals (needle insertion without infusion), fluorescent staining was not observed on the en bloc brain surface or in the coronal sections. Concentration of FITC-Dextran 71,200 in CSF The volume of CSF samples ranged from 78 to 215 µl. The mean CSF

Restricted access

Anthony Marmarou, Kenneth Shulman and James LaMorgese

O ur understanding of intracranial pressure (ICP) dynamics has led us to believe that compliance, as defined by the volume pressure curve, and the resistance to fluid absorption are the major parameters that control the rate of change and resting level of the ICP. This report describes the methods used in dealing with the nonlinear compliance of the cerebrospinal fluid (CSF) space and its relation to pressure, with emphasis on special techniques for rapid determination of both compliance and absorption resistance. These methods are then used to evaluate the