The perioperative fluid regimen is dependent on the quantity of fluid prescription as well as amount of electrolytes administered. 0.9% sodium chloride (saline) is one the most commonly used intravenous crystalloids in the world.
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It is commonly prescribed in surgical patients and has been shown to cause hyperchloraemic acidosis in large volumes, even in healthy subjects.
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Human studies have also shown sodium balance remains abnormal for up to two days post infusion of normal saline with associated suppression of the RAAS.
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Moreover, studies have reported higher complication rates and the need for renal replacement therapy in patients who had received 0.9% saline than in those who received balanced crystalloid solutions following major open abdominal surgery (Fig. 2).
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Furthermore, chloride-restrictive intravenous fluid therapy has been shown to reduce the incidence of acute kidney injury and the need for renal replacement therapy in ICU patients.
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A randomised controlled double-blinded crossover study where two litres of saline or Plasma-Lyte (a balanced solution) were administered intravenously to healthy volunteers reported for the first time in humans that saline resulted in reduced renal blood flow velocity and cortical tissue perfusion.
This is likely to further increase salt and water retention, with older adults at increased risk because of the age-related physiological changes and the high incidence of renal failure and heart failure in this group. Saline-induced hyperchloraemic acidosis was also suggested to prolong postoperative recovery through reduced gastric bloodflow and intramucosal pH in older adult patients.
Fig. 2. Complications that are increased with 0.9% saline relative to balanced crystalloids.
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In contrast