Original Article

Neurocritical Care

, 9:338

First online:

Does Brain Swelling Increase Estimated Specific Gravity?

  • Vincent DegosAffiliated withDepartment of Anesthesiology and Critical Care, Pitié-Salpêtrière Teaching Hospital, Assistance Publique-Hôpitaux de Paris, Pierre and Marie Curie Paris 6 University
  • , Ana-Rosa PereiraAffiliated withDepartment of Anesthesiology and Critical Care, Pitié-Salpêtrière Teaching Hospital, Assistance Publique-Hôpitaux de Paris, Pierre and Marie Curie Paris 6 University
  • , Thomas LescotAffiliated withDepartment of Anesthesiology and Critical Care, Pitié-Salpêtrière Teaching Hospital, Assistance Publique-Hôpitaux de Paris, Pierre and Marie Curie Paris 6 University
  • , Paola Sanchez-PeñaAffiliated withDepartment of Anesthesiology and Critical Care, Pitié-Salpêtrière Teaching Hospital, Assistance Publique-Hôpitaux de Paris, Pierre and Marie Curie Paris 6 University
  • , Mounir DaoudiAffiliated withDepartment of Anesthesiology and Critical Care, Pitié-Salpêtrière Teaching Hospital, Assistance Publique-Hôpitaux de Paris, Pierre and Marie Curie Paris 6 University
  • , Abderrezak ZouaouiAffiliated withDepartment of Radiology, Pitié-Salpêtrière Teaching Hospital, Assistance Publique-Hôpitaux de Paris, Pierre and Marie Curie Paris 6 University
  • , Pierre CoriatAffiliated withDepartment of Anesthesiology and Critical Care, Pitié-Salpêtrière Teaching Hospital, Assistance Publique-Hôpitaux de Paris, Pierre and Marie Curie Paris 6 University
  • , Louis PuybassetAffiliated withDepartment of Anesthesiology and Critical Care, Pitié-Salpêtrière Teaching Hospital, Assistance Publique-Hôpitaux de Paris, Pierre and Marie Curie Paris 6 UniversityDépartement d’Anesthésie-Réanimation, Hôpital de la Pitié-Salpêtrière Email author 

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Abstract

Objective

At the acute phase of traumatic brain injury (TBI), brain swelling contributes substantially to the development of secondary neurological lesions. Elucidating the pathophysiology of brain swelling is crucial to improve TBI management. In a previous study, specific gravity (SG) of the noncontused hemisphere, as estimated by computed tomography (CT), was higher in patients with high Marshall CT scores and severe brain swelling. The aim of this study was to investigate the relationship between estimated specific gravity (eSG) and clinical variable suggestive of brain swelling.

Design

Retrospective study of data from a prospectively established database.

Setting

Neurology ICU in a teaching hospital in Paris, France.

Participants

We studied 20 patients with severe traumatic brain injury (TBI), 20 patients with high-grade subarachnoid hemorrhage (SAH) presenting similar brain-swelling criteria, 20 patients with low-grade SAH, and 20 healthy controls.

Interventions

None.

Measurements and Results

Estimated brain specific gravity was acquired from CT images obtained at ICU admission. eSG was estimated in the overall intracerebral content and in a region-of-interest composed of white matter and the diencephalon. eSG in the region of interest was significantly higher in the TBI patients than in the high-grade SAH patients (1.0350 ± 0.0041 vs. 1.0310 ± 0.0019 g/ml, < 0.05). eSG was similar in the high-grade SAH, low-grade SAH, and control groups.

Conclusions

Our findings do not support a causal link between brain swelling and eSG elevation. The eSG increase in severe TBI patients is not due to brain swelling.

Keywords

Traumatic brain injury Specific gravity Computed tomography Subarachnoid hemorrhage Brain swelling Blood–brain barrier