Introduction/Purpose Fish oil (Omega-3 fatty acid) is commonly used by patients as a
natural anti-inflammatory to decrease joint pain from arthritis. Furthermore, fish oil
has been found to decrease the risk of coronary artery disease, decrease mild
hypertension, prevent cardiac arrhythmias and decrease blood triglyceride levels.
Supplements, including fish oil, are typically stopped 1-2 weeks prior to surgery as
there is an increased risk of perioperative bleeding. With modern blood management
techniques in joint replacement surgery, including the use of tranexamic acid, the risk
of perioperative bleeding may be minimized. With the risk being minimized fish oil may
not need to be stopped prior to surgery and could be continued immediately after surgery.
The anti-inflammatory effect of fish oil in the perioperative period may aid in
post-operative pain management. The purpose of this study is to determine if continuing
fish oil supplementation leads to higher blood loss in patients undergoing unilateral
total hip arthroplasty (THA). A secondary analysis is to determine if patients on fish
oil have less pain after THA.
Objectives
Primary Outcome Measures:
• Calculated total perioperative blood loss milliliters (mL) using Bourke's, Gross',
Camarasa's, and Lopez-Picado's formula based on post-operative (PO) D5 Hemoglobin and
Hematocrit
Secondary Outcomes Measures:
Incidence of blood transfusion
Post-operative day 1 Hemoglobin and Hematocrit
Post-operative pain scores
Pain medication usage (morphine equivalents)
Difference in wound complications (superficial and deep infection, drainage,
hematoma)
Study Design Open-label, adaptive randomized clinical trial with a 1:1 randomization
Study arms:
Control: No fish oil supplementation. Interventional: Fish oil supplementation started or
continued Fish-Oil naïve subjects will be started on fish oil 4 weeks prior to surgery
and continued until the 6 week follow up. Subjects already taking fish oil will be
switched to the study fish-oil formulation of two capsules twice daily (3000 mg of EPA
and DHA).
All subjects will be asked to stop all non-Fish Oil supplements 2 weeks prior to and 2
weeks after surgery.
Sample size: The primary outcome is blood loss, mean of 1200 mL with a reported standard
deviation of 340 mL. A non-inferiority trial to determine if there is no difference in
blood loss between subjects taking fish oil and subjects not taking fish-oil will require
50 subjects in each arm with 80% power lower limit of a one-sided 90% confidence
two-sided confidence interval that the difference between the two groups is one half the
reported standard deviation of 340 mL (170 mL). To allow for drop-outs, 60 subjects will
be enrolled in each arm.
Randomization: As patients already taking fish-oil supplements will likely not be willing
to discontinue their regimen, an adaptive randomization will be performed. Patients
already on fish-oil will be assigned to the Interventional Arm and the subsequent
randomization adjusted.
Study Procedures After being deemed eligible, potential study participants will be
approached about the study asked to sign an informed consent form that has been approved
by the internal review board. Patients that meet the inclusion criteria will be
randomized to either the control group or experimental group. Patients in the
experimental group will started on 3000 mg of EPA and DHA 4 weeks prior to surgery. The
fish oil will be continued in the perioperative period and until their 6 week follow up
appointment. Patients will be supplied the fish oil at no cost. Patients will stop all
other supplements and herbal medicines 2 weeks prior to surgery and will not restart the
supplements until 2 weeks after surgery.
Pre-operative hemoglobin and hematocrit will be obtained on all patients during
preadmission testing. All patients must stay one night in the hospital after surgery. A
post-day #1 and #5 hemoglobin and hematocrit will be obtained on all patients. Amount of
fluid collected in the wound drain will also be collected. Blood loss will be calculated
using the Bourke's, Gross', Camarasa's, and Lopez-Picado's formula. Data will be
collected on the rates of blood transfusions for each patient. Post-operative day 1 pain
scores will be determined for each patient using the visual analog scale. Pain medication
use through patient report will be collected and daily morphine equivalents starting on
the day of surgery up until the patients 6 week follow up will be calculated. Date and
quantity of any narcotic refill will be recorded. Data will also be collected on the rate
of wound complications in patients. Enrollment into the study is voluntary and
participants can voluntarily withdraw at any time.