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    Intraoperative Fluid Dosing in Adult Patients

    Doses IV fluids intraoperatively.


    This dosing tool is intended to assist with calculation, not to provide comprehensive or definitive drug information. Always double-check dosing of any drug and consult a pharmacist when necessary.


    Use in patients undergoing surgery who weigh ≥20 kg and do not have conditions that could otherwise result in fluid overload such as heart failure, COPD, or kidney failure on dialysis. This calculator provides a base hourly fluid requirement, fluid deficit, and hour-by-hour fluid requirement based on surgical needs.

    When to Use
    Why Use
    • Patients undergoing surgery.
    • Best applied in patients without conditions predisposing them to fluid overload, e.g. heart failure, COPD, kidney failure on dialysis.
    • The current suggested practice of intraoperative fluid management is a goal-directed approach where fluids are given with the intent of producing clinical benefit. In doing so, the aim is to optimize stroke volume, a practice that has repeatedly demonstrated a reduction in morbidity in the perioperative period (Noblett 2006).
    • Balanced fluid solutions such as Ringer’s Lactate or Iso-Lyte are recommended rather than normal saline because of similar electrolyte composition to plasma along with a buffer such as lactate, and large volumes of 0.9% saline can result in hyperchloremic acidosis. Crystalloid solutions will remain intravascularly before diffusing out for approximately 25–30 minutes, as opposed to colloids, which can last up to a day and a half (Shaw 2012).
    • In patients with significant heart failure, COPD, or ESRD, all of whom are susceptible to fluid overload, consider smaller amounts of fluid.
    • In longer cases, which may require large volumes of crystalloid fluid or result in major fluid shifts, consider colloid in conjunction with crystalloids.
    • Despite randomized trials finding significant improvements in length of stay, bowel function, and decreased postoperative complications of the kidney and lungs, only a minimal reduction in mortality has been demonstrated with the use of goal-directed fluid therapy over fixed volume and more liberal regimens (Giglio 2009, Nisanevich 2005).
    • Recent evidence suggests that the administration of arbitrary amounts of fluids in the operating room can have dire consequences. Demonstrated in the FEAST trial, 3,000 septic pediatric patients were treated with saline, albumin, or no fluids at all, resulting in death at 48 hours, most highly in those bolused large amounts of normal saline (Maitland 2005).
    • In a number of recent meta-analyses, patients receiving fluid using a goal-directed therapy regimen had improved postoperative outcomes with fewer renal, pulmonary, and gastrointestinal complications as well as decreased length of hospital stay and faster return of GI function (Giglio 2009, Nisanevich 2005, Corcoran 2012).


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    • Fluid output should be monitored during operations to evaluate tissue perfusion (0.5 mL/kg/hr urine in patients with Foley catheters may help guide decisions).
    • For most healthy patients with few co-morbidities undergoing minimally invasive procedures (i.e., in the outpatient setting) such as laparoscopic procedures, eye surgery, and other short cases, 1–2 L of a balanced electrolyte solution provides effective rehydration.
    • As always, use clinical judgment in order to fully evaluate a patient’s fluid requirement.
    • In longer cases, those with expected major fluid shifts, or with patients who cannot tolerate large amounts of IV fluid, consider the use of adjuvant colloid solutions to help maintain intravascular blood volume.
    • Consider special cases such as patients undergoing GI surgery who have had bowel prep and may have excess fluid loss and greater requirements than the average patient.

    Critical Actions

    • Be wary of fluid management in patients who cannot tolerate excessive amounts of IV fluids, as this can result in decreased healing time and increased hospital stays with complications.
    • Other intraoperative issues such as hypotension, tachycardia, and even EKG changes can often be attributed to the patient being severely hypovolemic and undergoing the stress of surgery, and, as such, the patient should be hydrated appropriately.


    • Hourly maintenance fluid, mL/hr = body weight, kg + 40 mL
    • NPO fluid deficit, mL = hourly maintenance fluid, mL/hr × time spent NPO, hrs
    • 1st hour fluids: ½ NPO fluid deficit + hourly maintenance fluid
    • 2nd hour fluids: ¼ NPO fluid deficit + hourly maintenance fluid + fluid loss from surgical trauma*
    • 3rd hour fluids: ¼ NPO fluid deficit + hourly maintenance fluid + fluid loss from surgical trauma*
    • 4th hour fluids and beyond: hourly maintenance fluid + fluid loss from surgical trauma*

    *Estimated fluid loss from surgical trauma:

    Minimal e.g. hernia repair, laparoscopy 2-4 mL/kg/hr (calculator uses 3 mL/kg/hr)
    Moderate e.g. open cholecystectomy, open appendectomy 4-6 mL/kg/hr (calculator uses 5 mL/kg/hr)
    Severe e.g. bowel resection 6-8 mL/kg/hr (calculator uses 7 mL/kg/hr


    Evidence Appraisal

    A meta-analysis by Corcoran et al examined use of liberal IV fluid administration intraoperatively versus a goal-directed strategy and the resulting outcomes. A number of online databases were searched for US randomized control trials of liberal fluids vs. goal-directed therapy. 3,861 patients from 23 goal-directed studies and 1,160 from 12 liberal fluid studies were reviewed. Patients in the liberal group of the LVR stratum had a higher risk of pneumonia, pulmonary edema, and a longer hospital stay. Using goal-directed therapy resulted in a lower risk of pneumonia, renal complications, and a shorter length of hospital stay compared to liberal fluid management. Liberal fluid therapy was associated with an increased length of hospital stay, time to first bowel movement, and risk of pneumonia compared to goal-directed therapy (Corcoran 2012).

    Postop GI dysfunction:

    Postoperative GI dysfunction is a frequent complication of patients undergoing surgery, postulated to be secondary to splanchnic hypoperfusion. A search of major online databases was conducted, and 3,410 patients were evaluated for the study over 16 controlled trials. They evaluated GI complications as major or minor, where major was considered life threatening or required surgical intervention, and minor required only medical therapy. Both major and minor GI complications were reduced using goal directed therapy (Giglio 2009).

    Clinician judgment vs. Doppler evaluation of fluid status:

    108 patients undergoing elective colorectal resection were studied in a double blind, prospective randomized control trial in which an esophageal Doppler probe was placed intraoperatively. In one group, patients received perioperative fluid at the anesthesiologist’s discretion, whereas in the other group, patients received fluid boluses per Doppler evaluation. Aortic flow time, stroke volume cardiac output, and cardiac index were all higher in the intervention group; additional improved outcomes included decreased postoperative hospital stay, fewer postoperative complications, and ability to tolerate PO intake earlier (Noblett 2006).

    Liberal vs. restrictive strategy:

    In this study, two different intraoperative fluid regimens were utilized and postoperative outcomes evaluated in 152 patients with ASA physical status of I-III and undergoing elective intra-abdominal surgery. Patients were randomly assigned to one of two groups and given either liberal or restrictive fluid volumes. Results included lower complication rate, earlier BM, and shorter hospital stays in the restrictive group as compared to the liberal group. They also found that postoperative days 1 to 3, the restrictive fluid group had significantly higher hematocrit and albumin concentrations (Nisanevich 2005).

    0.9% saline vs. Plasma-Lyte:

    In this study by Shaw et al, researchers looked at the morbidity and mortality effects of using 0.9% saline as compared to Plasma-Lyte, a balanced fluid solution. The hypothesis came as the result of the potential for high volumes of 0.9% saline to cause hyperchloremic acidosis. Looking at the Premier Perspective Comparative Database, 30,000+ patients who underwent major open abdominal surgery with 0.9% saline and 926 patients with balanced crystalloid solution were evaluated. They looked primarily at major morbidity and secondarily at acidosis-related complications. The researchers found that there was a 2% higher chance of mortality in the saline group, and using a match study, found that there was a 10% increase in chance of complications such as renal failure requiring dialysis, need for transfusions, electrolyte disturbances and infections in the saline group compared to the balanced fluid group (Shaw 2012).


    Original/Primary Reference

    Research PaperCorcoran T, Rhodes JE, Clarke S, Myles PS, Ho KM. Perioperative fluid management strategies in major surgery: a stratified meta-analysis. Anesth Analg. 2012;114(3):640-51.Research PaperGiglio MT, Marucci M, Testini M, Brienza N. Goal-directed haemodynamic therapy and gastrointestinal complications in major surgery: a meta-analysis of randomized controlled trials. Br J Anaesth. 2009;103(5):637-46.Research PaperNoblett SE, Snowden CP, Shenton BK, Horgan AF. Randomized clinical trial assessing the effect of Doppler-optimized fluid management on outcome after elective colorectal resection. Br J Surg. 2006;93(9):1069-76.Research PaperNisanevich V, Felsenstein I, Almogy G, Weissman C, Einav S, Matot I. Effect of intraoperative fluid management on outcome after intraabdominal surgery. Anesthesiology. 2005;103(1):25-32.Research PaperShaw AD, Bagshaw SM, Goldstein SL, et al. Major complications, mortality, and resource utilization after open abdominal surgery: 0.9% saline compared to Plasma-Lyte. Ann Surg. 2012;255(5):821-9.Research PaperMaitland K, Babiker A, Kiguli S, Molyneux E. The FEAST trial of fluid bolus in African children with severe infection. Lancet. 2012;379(9816):613.
    Dr. Tomas Corcoran

    About the Creator

    Tomas Corcoran, MD, is a clinical professor and research director in the department of anesthesia and pain medicine at Royal Perth Hospital in Perth, Australia. He was, notably, the chief investigator of a global study on the effects of dexamethasone on post-surgical emesis. Dr. Corcoran's clinical research focuses on surgical outcomes and anesthetics.

    To view Dr. Tomas Corcoran's publications, visit PubMed

    Content Contributors
    • David Convissar, MD
    Reviewed By
    • Steven Shulman, MD
    About the Creator
    Dr. Tomas Corcoran
    Content Contributors
    • David Convissar, MD
    Reviewed By
    • Steven Shulman, MD