Calc Function

    • Calcs that help predict probability of a diseaseDiagnosis
    • Subcategory of 'Diagnosis' designed to be very sensitiveRule Out
    • Disease is diagnosed: prognosticate to guide treatmentPrognosis
    • Numerical inputs and outputsFormula
    • Med treatment and moreTreatment
    • Suggested protocolsAlgorithm





    Chief Complaint


    Organ System


    Patent Pending

    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).


    Please fill out required fields.

    Next Steps
    Creator Insights


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