Cerebral effects of isovolemic hemodilution with a hypertonic saline solution.
ABSTRACT In view of a growing interest in the resuscitative use of hypertonic saline solutions, the authors have examined the cerebral effects of isovolemic hemodilution carried out over 1 hour (hematocrit decreased from 40% to 20%, stable arterial and right arterial pressures), using a hypertonic lactated Ringer's solution (HT-LR: Na+ 252 mEq/liter, osmolality 480 mOsm/liter). Experiments were carried out in anesthetized ventilated rabbits. Measured variables included cerebral blood flow (using the H2 clearance method), intracranial pressure (ICP), the electroencephalogram, spinal cord and skeletal muscle water content (%H2O), and the specific gravity of small (10- to 30-mg) tissue samples taken from different areas of the left hemisphere (including the cortex, thalamus, internal capsule, and hippocampus). The changes produced by HT-LR were compared with those seen in both undiluted control animals and in rabbits hemodiluted with normal saline (Na+ 155 mEq/liter, osmolality 310 mOsm/liter). The results demonstrate that hemodilution with HT-LR leads to the expected increases in serum Na+ and osmolality (158 +/- 6 mEq/liter and 320 +/- 5 mOsm/kg, respectively, mean +/- standard deviation) and that these were accompanied by reductions in the %H2O of all cerebral and extracerebral tissues, increases in the specific gravity of all tissue regions studied, and a decrease in ICP (1.9 +/- 0.7 mm Hg). By contrast, rabbits with hemodilution by normal saline showed no changes in either %H2O or specific gravity, but had significant increases in ICP (3.3 +/- 1.3 mm Hg). Cerebral blood flow increased in all animals hemodiluted with either HT-LR or normal saline by a combined average of +29 ml/100 gm/min. Although these studies were performed in neurologically normal animals, the combination of cerebral changes seen with HT-LR (cerebral dehydration, less peripheral edema, decreased ICP but with increased cerebral blood flow) suggests that this approach may have some advantages over the use of isotonic fluids, and may have some utility in the resuscitation of head-injured patients.
Archives of Surgery 09/1991; 126(9):1065. DOI:10.1001/archsurg.1991.01410330019002 · 4.30 Impact Factor
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ABSTRACT: La terapia hiperosmolar con manitol o solución salina hipertónica (SSH) es la principal estrategia médica para el manejo clínico de la hipertensión intracraneal (HIC) y del edema cerebral. La HIC y el edema cerebral suelen ser las consecuencias de lesiones cerebrales agudas y crónicas tales como el trauma craneoencefálico severo, el accidente cerebrovascular isquémico, la hemorragia intracerebral, la hemorragia subaracnoidea aneurismática, y los tumores e infecciones cerebrales. Ambas contribuyen a peores resultados neurológicos y producen mayor mortalidad en los pacientes neurocríticos.Revista Colombiana de Anestesiologia 11/2014; 43. DOI:10.1016/j.rca.2014.07.010
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ABSTRACT: Hyperosmolar therapy with mannitol or hypertonic saline solution is the main medical strategy for the clinical management of intracranial hypertension (IH) and cerebral oedema. IH and cerebral oedema are usually the result of acute and chronic brain injuries such as severe head trauma, ischaemic stroke, intracerebral haemorrhage, aneurismal subarachnoid haemorrhage, tumours and cerebral infections.Objective We conducted this research in order to assess the benefits and side effects of osmotherapy and to identify the current trends in the management of IH and cerebral oedema. These two conditions worsen neurological outcomes and are the major cause of mortality in neurological patients.In this article we show the current evidence supporting the use of HTS and mannitol, and examine the question of which of the two agents is considered the best option for the medical treatment of IH. We review the efficacy data for HTS compared with mannitol in terms of clinical considerations.Conclusion Data availability is limited because of small sample sizes, inconsistent methods and few prospective randomized comparative studies, although both agents are effective and have a reasonable risk profile for the treatment of cerebral oedema and IH. Currently, several trials show that HTS could be more effective in reducing ICP, with longer lasting effects. HTS maintains systemic and cerebral haemodynamics.11/2014; 43. DOI:10.1016/j.rcae.2014.07.010