====== Perioperative Intravenous Fluid Therapy ======

[[Fluid management]] is an important component of [[perioperative]] care for patients undergoing [[neurosurgery]]. The primary goal of fluid [[management]] in neurosurgery is the maintenance of [[normovolemia]] and prevention of [[serum osmolarity]] reduction. To maintain normovolemia, it is important to administer [[fluid]]s in appropriate amounts following appropriate [[method]]s, and to prevent a decrease in serum osmolarity, the choice of fluid is essential. There is considerable debate about the choice and optimal amounts of fluids administered in the perioperative period. However, there is little high-quality [[clinical research]] on [[fluid therapy]] for patients undergoing neurosurgery. A review of Ryu discussed the choice and optimal amounts of fluids in neurosurgical [[patient]]s based on the [[literature]], recent [[issue]]s, and perioperative fluid management practices.

Despite numerous studies on [[perioperative intravenous fluid therapy]], there is insufficient [[evidence]] to draw definitive conclusions regarding [[fluid management]] in neurosurgical patients.
Although evidence is still lacking, isotonic balanced [[crystalloid]] solutions should be considered the first-choice fluid, while hypotonic solutions should be avoided. Furthermore, [[colloid]] solutions should be used with caution, and their potential risks and benefits should be considered.
To achieve an optimal fluid volume status while avoiding overhydration and excessive restriction, the amount and duration of fluid administration should be considered, and an individualized fluid strategy is recommended using [[Goal-directed fluid therapy]] based on dynamic [[fluid]] parameters
((Ryu T. Fluid management in patients undergoing neurosurgery. Anesth Pain Med (Seoul). 2021 Jul;16(3):215-224. doi: 10.17085/apm.21072. Epub 2021 Jul 22. PMID: 34352963.)).
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A [[crystalloid]] fluid contains small molecular substances without high molecular substances, and it is classified as hypotonic, isotonic, or hypertonic according to its [[osmolarity]]. [[Lactated Ringer's]] solution (LR), a commonly used [[crystalloid]], is hypotonic at 273 mOsm/L. Low plasma [[osmolarity]] can cause [[cerebral edema]]. Therefore, hypotonic solutions, such as LR, are avoided, while [[normal saline]] (NS) has traditionally been used as the main fluid in patients with neurosurgery 
((Tommasino C, Picozzi V. Volume and electrolyte management. Best Pract Res Clin Anaesthesiol 2007; 21: 497-516.)).
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Patients who received balanced [[crystalloid]] (BC) during Unruptured Intracranial Aneurysm Clipping had lower incidence of [[metabolic acidosis]], earlier extubation and shorter ICU stay compared to those who received NS. Therefore, using BC as a peri-operative fluid can be recommended for patients who undergo surgery for UIA
((Kang J, Song YJ, Jeon S, Lee J, Lee E, Lee JY, Lee E, Bang JS, Lee SU, Han MK, Oh CW, Kim T. Intravenous Fluid Selection for Unruptured Intracranial Aneurysm Clipping : Balanced Crystalloid versus Normal Saline. J Korean Neurosurg Soc. 2021 Jul;64(4):534-542. doi: 10.3340/jkns.2020.0262. Epub 2021 May 28. PMID: 34044495; PMCID: PMC8273783.)).
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In [[prone]] [[elective]] neurosurgical [[patient]]s, the baseline values of  pulse pressure variation (PPV) and  stroke volume variation (SVV) and the end-expiratory occlusion test (EEOT)  fail to predict fluid responsiveness, while the tidal volume challenge (VTC) is a very reliable functional hemodynamic test and could be helpful in guiding intraoperative fluid therapy
((Messina A, Montagnini C, Cammarota G, Giuliani F, Muratore L, Baggiani M, Bennett V, Della Corte F, Navalesi P, Cecconi M. Assessment of Fluid Responsiveness in Prone Neurosurgical Patients Undergoing Protective Ventilation: Role of Dynamic Indices, Tidal Volume Challenge, and End-Expiratory Occlusion Test. Anesth Analg. 2020 Mar;130(3):752-761. doi: 10.1213/ANE.0000000000004494. PMID: 31651455.)).

===== Intraoperative Intravenous Fluid Therapy =====


[[Intraoperative Intravenous Fluid Therapy]].

===== Crystalloid Fluids =====
[[Crystalloid Fluids]]

===== Colloid =====
[[Colloid]]