SCIENTIFIC ARTICLE. Hydroelectrolytic balance and cerebral relaxation with hypertonic isoncotic saline versus mannitol (20%) during elective neuroanesthesia. A fundamental basis of clinical surgery is the patients’ hydroelectrolytic balance. In conjunction with this topic, the distribution of electrolytes aming the hydric. Open Access. Hydroelectrolytic Balance and Cerebral Relaxation with Hypertonic Isoncotic Saline versus Mannitol (20%) During Elective Neuroanesthesia.
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Cerebral relaxation during intracranial surgery is necessary, and hiperosmolar therapy is one of the measures used to this end. Frequently, neurosurgical patients have sodium imbalances. The objective of the present study was to quantify and determine cerebral relaxation and duration of hydroelectrolytic changes secondary to the use of mannitol versus hypertonic isoncotic solution HIS during neurosurgery.
The volume of intravenous fluids infused and diuresis were recorded. A statistically significant difference in cerebral relaxation between both groups was not observed.
Although several changes in electrolyte levels and acid-base balance with mannitol or HIS reached statistical significance only the reduction in plasma sodium 30 minutes after infusion of mannitol, mean of 6. L -1and the increase in chloride, mean of 5. L -1 and 5. L -1 30 and minutes after infusion of HIS, caused a transitory dislocation of serum ion levels from normal range. A single dose of hypertonic isoncotic saline solution [7. Cerebral relaxation is essential in anesthesia for intracranial surgery, mandatory in cases of intracranial hypertension, and of great interest for other neurosurgical approaches.
It has been considered a neuroprotective measure as it can reduce surgical compression, local hypoperfusion, and cerebral ischemia 1.
After opening of the dura-mater intracranial pressure ICP is virtually zero but a non-relaxed brain can reduce the working conditions of neurosurgeons 2. Administration of osmotherapy at the onset of craniotomy before opening the dura-mater is one of the interventions used to produce cerebral relaxation in elective neurosurgeries. Osmolality is the primary determinant of water movements through the intact blood-brain barrier BBBand it is predictable.
If we increase serum osmolality, normal brain tissue would dehydrate, and the cerebral volume, as well as the intracranial pressure, would be reduced 3. On the other hand, hyperosmotic therapy produces hydroelectrolytic changes that may be a confounding factor in the management of neurosurgical patients who frequently have water and sodium imbalances usually attributed to cerebral salt wasting syndrome, inappropriate antidiuretic hormone secretion, and diabetes insipidus 4.
Mannitol has become the traditional basis of hyperosmolar therapy 5. However, it can be associated with severe adverse effects such as intravascular volume depletion, rebound ICP elevation, and renal failure 6.
Although it also has potential side effects, hypertonic saline solutions HS have gained renewed interest as an alternate therapy and recently have been use in neurosurgical patients 7. Several clinical studies comparing the effects of mannitol and HS on intracranial pressure have suggested that HS is as effective as mannitol if not better for treating intracranial hypertension 8.
The objective of the present study was to evaluate cerebral relaxation and changes in hydroelectrolytic balance after the intraoperative administration of HS 7. Exclusion criteria were as follows: L -1metabolic disorders, treatment with hyperosmotic solution up to 24 hours before surgery, or history of heart or renal failure. All patients were intubated and volume-controlled mechanical ventilation with a mixture of oxygen and room air was initiated.
Cisatracurium was the muscle relaxant used.
balance hidroelectrolitico | Spanish to English | Medical: Cardiology
If necessary, inhalational anesthesia with sevoflurane, at a minimal alveolar concentration of 0. Normovolemia was maintained by the intravenous administration of 0.
After incision of skin, the parameters evaluated were recorded; they included: The same variables were then evaluated and uydroelectrolytic 30 and minutes after the end of the infusion of hyperosmolar therapy besides the intravenous volume administered and dieresis at the beginning of the hyperosmolar infusion, and 30 and minutes after its termination.
Cerebral relaxation was evaluated by the same surgeon who was blind to the hyperosmolar therapy used after its administration upon opening of the dura-mater, in a four-point scale: Gaussian distribution of variables was assessed by Shapiro normalcy test.
ANOVA followed by Bonferroni test was used to compare the intragroup means, while the Student t test was used to compare intergroup means. The demographic data of this group included: In the HIS group, six patients were scheduled for elective craniotomy for cerebral aneurism, one for arteriovenous malformation, and five for cerebral tumor. Statistically significant differences in demographic data between both groups were not observed.
Changes in serum sodium concentration: Changes in serum chloride concentration: Changes in serum calcium levels: Changes in serum potassium levels: Serum potassium levels were increased by 0. A difference between the baseline level of BE and that 30 minutes after infusion was not observed.
Diuresis and intravenous volume administered intraoperatively: Cerebral relaxation according to the four-point scale: Changes in serum sodium levels: Mean baseline sodium levels were L -1with significant changes 30 minutes Serum sodium levels showed a mean increase of 4.
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L balancd and 3. L -1 30 and minutes after infusion respectively. Changes in serum osmolality: Baseline serum osmolality was Serum osmolality showed a mean increase of Changes in other serum electrolytes: Mean baseline calcium serum levels were 1.
Mean potassium serum levels were 3. L -1and it showed a significant change 30 minutes 3. Between 30 and minutes after infusion of HIS, a significant difference in mean serum potassium concentrations were also observed Table II. L -1and they showed a significant change 30 minutes Changes in hemoglobin concentration: Mean baseline hemoglobin concentration was L -1with a significant change 30 minutes Mean baseline BE was L -1showing a significant change 30 minutes Mean baseline serum HCO3 -2 was L -1with significant changes minutes Mean baseline AG was 7.
Diuresis and intraoperative intravenous volume administration: Diuresis during the period immediately before HIS administration and 30 minutes after administration was Between 30 and minutes after the administration of HIS the diuresis was Regarding cerebral relaxation the neurosurgeon did not consider the brain of any patient inadequate, and statistically significant differences between both groups were not observed.
One hundred and twenty minutes after hyperosmolar therapy, the direction in serum sodium changes remained different in both groups Table III.
The intravenous volume administered was not different between both groups, but diuresis was. The present study results showed that hyperosmolar therapy with HIS, composed of 7. And although statistically significant differences in diuresis and serum electrolyte and acid-base changes are observed in the first two hours after the administration of both types of hyperosmolar therapies, and among them most of these changes are within or very close to normal range, they are apparently not clinically harmful.
The effects of hypertonic saline HS in the brain of patients without intracranial hypertension have been investigated in patients undergoing elective craniotomies for several surgical procedures 7,9, Using a cerebral relaxation scale similar to the one we used, Gemma et al. On the other hand, Rozet et al. The main mechanism of action of hyperosmolar solutions is the generation of an osmolar gradient across the blood brain barrier BBBdue to its impermeability to solutes sodium and mannitol 10leading to contraction of cerebral tissue were the BBB is intact and therefore reducing the ICP.
The effectivity of hyperosmolar solutes depends on their reflection coefficient, which determines the relative impermeability of BBB to the solute where 1 one means a solute for which the barrier is absolutely impermeable and 0 zero means a solute for which it is completely permeable The reflection coefficient of the membrane for sodium is 1 different from the reflection coefficient for mannitol, which is 0.
In the periphery muscles, lungs, and other tissues the reflection coefficient of the endothelial membrane for sodium is only 0. Thus, in the periphery water movement from interstitial space to intravascular space is governed by the serum concentration of large molecules oncotic gradient. In contrast with peripheral capillaries in cerebral capillaries when the BBB is intact the endothelial membrane is impermeable to sodium, and water movements across BBB is determined by the total osmotic gradient generated by both large molecules and small ions 14while fluid mobilization after the HS administration is from intracellular and interstitial spaces to intravascular space.
When serum osmolality increases the osmotic gradient drives water out of brain tissue. In our study a mean increase in serum osmolality of only Serum osmolality was always below the safe threshold proposed mOsm. L -1 to L -1 after 15 minutes and to L -1 after 60 minuteswhich correlated with a reduction in ICP.
Therefore, although small, the changes in serum osmolality after HS in our study probably contributed to the perfect or satisfactory cerebral relaxation observed by the neurosurgeon. This study used 7. The effect of HS alone is short-acting With the addition of a colloid, its clinical effect can be prolonged for hours In addition to creating an osmolar gradient across BBB, the reduction in CSF production, improvement in blood rheology, and anti-inflammatory properties of HS and mannitol seem to have a role in bran therapy 10,18, An impaired BBB has the potential to leak out osmotic substances into the brain parenchyma causing a reverse osmotic effect The combination of HS and colloid could increase concerns about its safe use.
However, in elective neurosurgeries BBB would be intact in most part of the brain. Austrian physicians have extensive experience with the use of a large number of solutions composed of 7.