A 2019 review evaluated the latest evidence on perioperative fluid therapy for major surgery, focusing on the optimal type and volume of fluids administered. Preoperative fluid management aims to prevent hypovolemia or dehydration before surgery. Guidelines from the American Society of Anesthesiologists recommend unrestricted intake of clear fluids up to 2 hours prior to elective procedures. This is supported by a meta-analysis showing reduced aspiration risk with clear liquid intake compared to overnight fasting. Natural saliva and gastric secretions contribute 500 to 1,250 mL of fluid after an 8-hour fast, and allowing clear fluids dilute gastric acidity, enhancing comfort and safety without increasing gastric volume. Some guidelines have shifted from “allow” to “encourage” clear fluids, though this needs further validation. Clear liquids include water, fruit juice (without pulp), carbonated drinks, and black coffee. Enhanced Recovery After Surgery (ERAS) protocols often include carbohydrate drinks 2 hours prior to surgery, potentially reducing insulin resistance and improving patient satisfaction while minimizing thirst and postoperative complications. ERAS guidelines also advocate for an early shift from IV to oral fluid therapy after surgery, typically within 24 hours for many patients. This transition helps preserve gastrointestinal motility and limits fluid loss into the bowel. For a summary of key points for preoperative, intraoperative, and postoperative fluid therapy, please refer to Table 1. Perioperative fluid therapy in major surgery is limited to IV fluid management. [1], [2], [3]
A 2016 joint consensus statement by the American Society for Enhanced Recovery (ASER) and the Perioperative Quality Initiative (POQI) on perioperative fluid management in an enhanced recovery pathway for colorectal surgery provide recommendations that aim to optimize fluid management before, during, and after surgery (See Table 2 for full recommendations). Prior to surgery, unrestricted access to clear fluids is recommended for oral intake up to two hours before the induction of anesthesia. Additionally, the guidance highlights that clear fluids used for oral hydration should contain at least 45 grams of carbohydrates to improve insulin sensitivity. During surgery, the guidance states that a hemodynamic framework should be applied to guide fluid management; intraoperative goal-directed fluid therapy (GDFT) is considered safe for most patients undergoing major colorectal surgery. The focus of fluid management strategies should be on identifying clinical problems that can be resolved by fluid therapy and determining the appropriate type and amount of fluid to be administered. [3]
Postoperatively, it is recommended that patients who are able to tolerate oral fluids should be given unrestricted access to them, as this improves patient satisfaction and likely eliminates the need for intravenous fluid administration. A recent 2024 article further discusses the role of restrictive perioperative fluid protocols within the ERAS pathway in the context of colorectal surgery. The authors note that standardized definitions of restrictive fluid regimens are currently lacking, as these definitions often depend on conflicting evidence, institutional protocols, and personal clinician preferences. One of the challenges associated with implementing restrictive fluid protocols is ensuring proper patient selection. For a summary of institutional-specific preoperative, intraoperative, and postoperative measures within a standardized ERAS protocol, please refer to Table 3. [3], [4]
For many major non-cardiac operations, ERAS pathways have become more utilized as a part of perioperative care, resulting in better clinical outcomes. One key element is to maintain preoperative hydration, often done orally, and to transition to early oral fluids and feeding post-surgery; guidance from one article recommends discontinuation of IV fluids and immediate oral intake as tolerated 0-12 h postoperatively, when the patient is tolerating oral intake. Another article reports use of a modified preoperative oral rehydration therapy (PO-ORT), in which administration of an oral rehydration solution (ORS) with a hyper-concentrated carbohydrate (H-CHO) product has been associated with decreased length of stay and a reduction in parenteral treatment in preoperative periods in Japan. Intraoperative fluid management is recommended to be individualized based on fluid and hemodynamic parameters matching patient and surgical risk, though guidance is tailored towards intraoperative infusion solutions. [5], [6], [7]
Although not limited to hospitalized patients, one 2018 article provides a hospital-based oral rehydration strategy, which was utilized by the institution when Hurricane Maria caused a critical shortage of IV fluids. The protocol aims for emergency department (ED) patients to receive 500 to 1,000 mL of oral fluids while present, as their likelihood of successful oral rehydration at home is more likely (see Table 4). Notably, this protocol is specific to patients with mild dehydration (e.g., acute gastroenteritis, pregnancy-related hyperemesis, mild viral upper respiratory infection or pharyngitis); patients who are unable to receive oral intake or who have moderate to severe dehydration were excluded from the protocol. [8]