Intrathecal Magnesium and Postoperative Analgesia

Study Overview
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Brief Summary
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Magnesium is implicated in the activation of NMDA receptors by amino-excitatory acids in the central nervous system [1]. Magnesium deficiency is associated to an increased activation of these receptors, and to an increased sensitivity to pain in animals. Spinal cord is the site of sensitization of pain, mainly mediated by the NMDA receptors, and intrathecal magnesium may have anti-hyperalgesic effect when administered intrathecally [2]. As intrathecal magnesium has already been used in humans for treatment of eclampsia, we stated that it could also improve postoperative analgesia and reduce the need for auto-administered morphine if given (50 mg of magnesium sulfate) with the intrathecal anesthetic drugs (bupivacaine and sufentanil) injected for orthopedic surgery.

Detailed Description
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Magnesium is implicated in the activation of NMDA receptors by amino-excitatory acids in the central nervous system [1]. Magnesium deficiency is associated to an increased activation of these receptors, and to an increased sensitivity to pain in animals. Spinal cord is the site of sensitization of pain, mainly mediated by the NMDA receptors, and intrathecal magnesium may have anti-hyperalgesic effect when administered intrathecally [2]. As intrathecal magnesium has already been used in humans for treatment of eclampsia, we stated that it could also improve postoperative analgesia and reduce the need for auto-administered morphine if given (50 mg of magnesium sulfate) with the intrathecal anesthetic drugs (bupivacaine and sufentanil) injected for orthopedic surgery.

Official Title
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Effects of a Single Dose of Intrathecal Magnesium Sulfate on Postoperative Morphine Consumption After Total Hip Replacement

Conditions
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Total Hip Replacement

Intervention / Treatment
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* Drug: intrathecal magnesium sulfate


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Total hip replacement under intrathecal anesthesia. Exclusion Criteria: General anesthesia (alone or not) Intolerance to morphine Misunderstanding of the use of the device for intravenous patient-controlled administration of morphine.

Ages Eligible for Study
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Minimum Age: 56 Years
Maximum Age: 93 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Single Group Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: intrathecal magnesium sulfate<br> | Drug: intrathecal magnesium sulfate<br>* intrathecal magnesium sulfate<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Reduction of morphine consumption in the postoperative period. |  | in the postoperative period | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Duration of sensory and motor blockade induced by the intrathecal anesthesia ; side effects; postoperative pain (visual analogue scale). |  | postoperative pain | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Magnesium, Pain, Morphine, Intrathecal, NMDA, Elective total hip replacement under intrathecal anesthesia