Lower Doses of Intrathecal Morphine for Knee Surgery
Author Information
Author(s): Hassett Patrick, Ansari Bilal, Gnanamoorthy Pachaimuthu, Kinirons Brian, Laffey John G
Primary Institution: Galway University Hospitals and National University of Ireland, Galway, Ireland
Hypothesis
What is the efficacy and side-effect profile of lower doses of intrathecal morphine in patients undergoing total knee arthroplasty?
Conclusion
200 μg of intrathecal morphine provides comparable analgesia to 300 μg and is recommended for postoperative pain management in knee arthroplasty.
Supporting Evidence
- 200 μg and 300 μg of IT morphine provided comparable analgesia.
- 100 μg of IT morphine resulted in higher pain scores and greater need for supplemental morphine.
- No significant differences in side effects like PONV, pruritus, or respiratory depression were found between groups.
Takeaway
This study found that using 200 micrograms of morphine in the spine helps with pain after knee surgery just as well as using 300 micrograms, but with fewer side effects.
Methodology
A prospective, randomized, controlled, double-blind study evaluating 100, 200, and 300 μg of intrathecal morphine in 60 patients over 60 years old undergoing knee arthroplasty.
Limitations
The study was powered to detect differences in analgesic efficacy rather than side effects, which may limit the detection of subtle side effect differences.
Participant Demographics
Patients were over the age of 60, with ASA physical status I-III.
Statistical Information
P-Value
0.006
Statistical Significance
p<0.05
Digital Object Identifier (DOI)
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