Traditional vs Oral Fluid Management in Total Knee Arthroplasty

Purpose: Evidence-based guidelines on optimal perioperative fluid management have not been established in patients undergoing orthopaedic surgery. Recent randomized trials in major abdominal surgery suggest that large amounts of IV fluid may increase morbidity and hospital stay. This study will investigate the effects of two regimens of intraoperative fluid management ("traditional" vs. "oral") with physiologic and patient function as primary outcome measures after surgery.

Evidence-based guidelines on optimal perioperative fluid management have not been established in patients undergoing orthopaedic surgery. Typical intraoperative and post-operative fluid management has been arbitrary without evidence based guidelines established following total joint replacement. The investigators have observed many patients post-operatively with side effects such as fluid overload leading to medical complications requiring either prolonged hospitalization or readmission. Additionally, this overload may lead to wound healing complications secondary to fluid shifts which may be devastating in this patient population. Recent randomized trials in major abdominal surgery suggest that large amounts of IV fluid may increase morbidity and hospital stay. Additionally, this increase fluid may be detrimental in patients with anastomosis leading to failure and/or complications in this patient population. The investigators have defined to specific groups of interest to study in this patient population with regards to fluid management. The first group is the "traditional" IV fluid group where the anesthesiologist gives an unspecific amount of fluid intraoperatively and post-operatively the patient gets a set amount of fluid based on "protocol" on the orthopaedic floor (i.e. 75 cc/hour until good oral intake). This is the protocol utilized by most orthopaedic practices throughout the United States. The second group is defined as patients who are given a specific protocol preoperatively to optimize hydration, followed by limited fluids intraoperatively based on physiologic parameters. This study will investigate the effects of two regimens of intraoperative fluid management ("traditional" vs. "oral") with

Eligibility Criteria:
Inclusion Criteria:

• Patients between the ages of 18-75 years old undergoing a primary total knee arthroplasty for a diagnosis of degenerative osteoarthritis who do not meet the exclusion criteria listed below

Exclusion Criteria:

* Volume-dependent cardiac conditions:
* Aortic stenosis
* Pulmonary valve stenosis
* Subaortic stenosis
* Severe Aortic Insufficiency
* Chronic systolic heart failure
* Eisenmeinger Syndrome
* Severe pulmonary HTN
* Chronic or paroxysmal dysrhythmias
* Pre-operative electrolyte abnormalities
* Abnormalities of the HPA (hypothalamic-pituitary axis)
* Stage 3 Chronic Kidney Disease (or worse)
* Patients taking angiotensin receptor blockers (ARB)
* Patients with uncontrolled diabetes mellitus (patient with A1C of 7+ or on insulin)
* Patients whose BMI is \> 35 38 or \< 19
* Current use of long acting narcotic medication or 3 or more months of daily short acting narcotic medication
* Patients at risk for electrolyte abnormalities, dehydration or intra-operative hypotension. (patients taking angiotensin receptor blockers, ACE inhibitors (48 hours prior to surgery) and Diuretics)
* Patients with severe, untreated or uncontrolled GERD.
* Patients that cannot receive spinal anesthesia (e.g. patient with back fusions)
* Pre-Operative Anemia