Glycerol Dehydrates Oedematous as Well as Normal Brain in Dogs

Abstract

1. Although the effect of glycerol on reducing intracranial pressure has been widely investigated, only a few studies have reported its dehydrating effect on brain oedema caused by infarction, ischaemia, microembolism and cold injury, but none on traumatic oedema. In this study the effects of glycerol (1 g/kg, i.v. bolus infusion at a rate of 0.04 g/kg per min) on traumatic and cryogenic cerebral oedema and on normal brain were compared in the anaesthetized dog. The tissue water content was measured with the gravimetric method. 2. Oedema resulting from mechanical trauma was initiated 4 h prior to treatment with glycerol (8 dogs) or vehicle (5 dogs) by closed head contusion with fixed force under general anaesthesia. Tissue samples underneath the region of contusion were taken, before and 1 h after infusion of glycerol or vehicle, for the measurement of water content. 3. Glycerol infusion decreased the water content in white matter of the traumatic brain model from 76.54 +/- 1.70% to 70.73 +/- 1.54% (P < 0.001). In normal brain the reduction was from 68.42 +/- 0.48% to 65.36 +/- 0.39% (P < 0.001). Neither vehicle nor glycerol infusion resulted in significant changes in specific gravity of the gray matter. 4. Cryogenic oedema was initiated 3 h prior to the infusion of glycerol or vehicle by applying unilaterally a brass conical cup (bottom diameter 1 cm) filled with dry ice-acetone (-65 degrees C) to the exposed dura for 1 min. The contralateral hemisphere, which was not subjected to cold injury, was used for determination of water content of normal gray and white matter. 5. Glycerol infusion decreased the water content in the white matter of the cold-injured region from 75.38 +/- 0.69% to 72.57 +/- 0.58% (P < 0.001). In the normal white matter the reduction was from 68.63 +/- 0.34% to 65.48 +/- 0.49% (P < 0.001). 6. Our data indicate that glycerol decreases water content of the white matter in traumatic and cold-injured oedematous brain as well as in normal brain.

Potentially Harmful Excipients: State of the Art for Oral Liquid Forms Used in Neonatology and Pediatrics Units

“…Neurological effects such as acute encephalopathy have also been reported in the literature when high concentrations were used in adults [ 42 ]. This neurological toxicity may be explained by a reversible relaxation of the blood–brain barrier due to the osmotic property of glycerol, which has been observed in animal models [ 43 , 44 ].…”

Dehydration Encephalopathy: A Neurological Emergency in the Older Adults

“…Elderly persons with WMLs, frontal hypoperfusion, and electroencephalographic high‐amplitude slow waves are prone to develop DE. The exact relationship between WMLs and development of DE is uncertain, but studies have shown that experimental slow dehydration from acute edema challenge is greater in white matter than in gray matter 7,8 . In cases of hypernatremia, rebound brain edema due to overhydration might contribute to the generation of DE.…”