Comparison of Postoperative Analgesic Effect of Intrathecal Magnesium and Fentanyl Added to Bupivacaine in Patients Undergoing Lower Limb Orthopedic Surgery

• Time to first requirement of analgesic supplement [ Time Frame: time to first requirement of analgesic supplement from the time of injection intrathecal anesthetic solution ] [ Designated as safety issue: Yes ]
  analgesic administration was initiated by patient request(verbal rating scale[ VRS]>4)
• postoperative analgesic requirements [ Time Frame: 12 hours postoperative ] [ Designated as safety issue: Yes ]
  postoperative analgesic requirements will be assessed by verbal rating scale (VRS) from 0 to 10 (0no pain, 10maximum imaginable pain).Each administration was initiated by patient request( VRS>4)

• Sensory block onset time will be assessed by a pinprick test [ Time Frame: sensory block will be assessed by pinprick test every 10 seconds following intrathecal injection ] [ Designated as safety issue: Yes ]
  The onset of sensory block was defined as the time between the end of injection of the intrathecal anesthetic and the absence of pain at the T10 dermatome
• duration of sensory block will be assessed by a pinprick test [ Time Frame: sensory block will be assessed by pinprick test every 5 minuts following intrathecal injection ] [ Designated as safety issue: Yes ]
  The duration of sensory block was defined as the time between the end of injection of the intrathecal anestheticthe time and regression of two segments from the maximum block height
• the onset of motor block will be assessed by the modified Bromage score [ Time Frame: every10 seconds following intrathecal injection ] [ Designated as safety issue: Yes ]
  The onset of motor block was defined as the time between the end of injection of the intrathecal anesthetic to Bromage block 1
• duration of motor block will be assessed by the modified Bromage score [ Time Frame: every 5 minuts following intrathecal injection ] [ Designated as safety issue: Yes ]
  duration of motor block was defined the time from intrathecal injection to Bromage score0
• hemodynamic variables is assessed by noninvasive automatic blood pressure measurement and electrocardiogram monitoring [ Time Frame: 5min before the intrathecal injection ] [ Designated as safety issue: Yes ]
• hemodynamic variables is assessed by noninvasive automatic blood pressure measurement and electrocardiogram monitoring [ Time Frame: 2minutes after intrathecal injection ] [ Designated as safety issue: Yes ]
• hemodynamic variables is assessed by noninvasive automatic blood pressure measurement and electrocardiogram monitoring [ Time Frame: 4minutes after intrathecal injection ] [ Designated as safety issue: Yes ]
• hemodynamic variables is assessed by noninvasive automatic blood pressure measurement and electrocardiogram monitoring [ Time Frame: 6minutes after intrathecal injection ] [ Designated as safety issue: Yes ]
• hemodynamic variables is assessed by noninvasive automatic blood pressure measurement and electrocardiogram monitoring [ Time Frame: 8minutes after intrathecal injection ] [ Designated as safety issue: Yes ]
• hemodynamic variables is assessed by noninvasive automatic blood pressure measurement and electrocardiogram monitoring [ Time Frame: 10minutes after intrathecal injection ] [ Designated as safety issue: Yes ]
• hemodynamic variables is assessed by noninvasive automatic blood pressure measurement and electrocardiogram monitoring [ Time Frame: 15minutes after intrathecal injection ] [ Designated as safety issue: Yes ]
• hemodynamic variables is assessed by noninvasive automatic blood pressure measurement and electrocardiogram monitoring [ Time Frame: 20minutes after intrathecal injection ] [ Designated as safety issue: Yes ]

Magnesium has been suggested that NMDA (N-methyl D-aspartate)receptor antagonists induce preemptive analgesia when administrated before tissue injury , thus decreasing the subsequent sensation of pain.

Following Ethics Committee approval and informed patients consent, Ninety patients 20-60 yr old ASA physical status I or II, scheduled for femur surgery under spinal anesthesia, were studied in a prospective, double-blinded, randomized way. The patients were randomly allocated to one of three groups of 30 each. The magnesium group (groupM) received bupivacaine 15mg combined with 0.5ml magnesium 10%,the fentanyl group (group F) received bupivacaine 15mg combined with0.5 ml fentanyl[25microgram] and the placebo group (group P) received bupivacaine 15mg combined with 0.5ml distilled water intrathecally . Time to first requirement of analgesic supplement, Sensory block onset time, maximum sensory level , onset of motor block, duration of blockade, hemodynamics variables, the incidence of hypotension, ephedrine requirements, bradycardia ,hypoxemia [Saturation of peripheral oxygen (SpO2)<90], postoperative analgesic requirements and Adverse events, such as sedation, dizziness , Pruritus and postoperative nausea and vomiting were recorded. Patients were instructed preoperatively in the use of the verbal rating scale (VRS) from 0 to 10 (0no pain, 10maximum imaginable pain) for pain assessment. If the VRS exceeded four and the patient requested a supplement analgesic, methadon5 mg intravenously , was to be given for post-operative pain relief as needed .

• Drug: Fentanyl
  Ninety patients 20-60 yr old American Society of Anesthesiologists ( ASA) physical status I or II, scheduled for femur surgery under spinal anesthesia, were studied in a prospective, double-blinded, randomized way. The patients were randomly allocated to one of three groups of 30 each. The magnesium group (groupM) received bupivacaine 15mg combined with 0.5ml magnesium 10%,The fentanyl group (group F) received bupivacaine 15mg combined with0.5 ml fentanyl[25microgram] and The placebo group (group P) received bupivacaine 15mg combined with 0.5ml distilled water(intrathecally) for each three groups 5 minutes prior to surgery)
• Drug: placebo(distilled water)
  Ninety patients 20-60 yr old American Society of Anesthesiologists ( ASA) physical status I or II, scheduled for femur surgery under spinal anesthesia, were studied in a prospective, double-blinded, randomized way. The patients were randomly allocated to one of three groups of 30 each. The magnesium group (groupM) received bupivacaine 15mg combined with 0.5ml magnesium 10%,The fentanyl group (group F) received bupivacaine 15mg combined with0.5 ml fentanyl[25microgram] and The placebo group (group P) received bupivacaine 15mg combined with 0.5ml distilled water(intrathecally) for each three groups 5 minutes prior to surgery)
• Drug: magnesium sulphate
  Ninety patients 20-60 yr old American Society of Anesthesiologists ( ASA) physical status I or II, scheduled for femur surgery under spinal anesthesia, were studied in a prospective, double-blinded, randomized way. The patients were randomly allocated to one of three groups of 30 each. The magnesium group (groupM) received bupivacaine 15mg combined with 0.5ml magnesium 10%,The fentanyl group (group F) received bupivacaine 15mg combined with0.5 ml fentanyl[25microgram] and The placebo group (group P) received bupivacaine 15mg combined with 0.5ml distilled water(intrathecally) for each three groups 5 minutes prior to surgery)

• Active Comparator: fentanyl
  Ninety patients 20-60 yr old American Society of Anesthesiologists ( ASA) physical status I or II, scheduled for femur surgery under spinal anesthesia, were studied in a prospective, double-blinded, randomized way. The patients were randomly allocated to one of three groups of 30 each. The magnesium group (groupM) received bupivacaine 15mg combined with 0.5ml magnesium 10%,The fentanyl group (group F) received bupivacaine 15mg combined with0.5 ml fentanyl[25microgram] and The placebo group (group P) received bupivacaine 15mg combined with 0.5ml distilled water(intrathecally) for each three groups 5 minutes prior to surgery)
  Intervention: Drug: Fentanyl
• Placebo Comparator: placebo
  Ninety patients 20-60 yr old American Society of Anesthesiologists ( ASA) physical status I or II, scheduled for femur surgery under spinal anesthesia, were studied in a prospective, double-blinded, randomized way. The patients were randomly allocated to one of three groups of 30 each. The magnesium group (groupM) received bupivacaine 15mg combined with 0.5ml magnesium 10%,The fentanyl group (group F) received bupivacaine 15mg combined with0.5 ml fentanyl[25microgram] and The placebo group (group P) received bupivacaine 15mg combined with 0.5ml distilled water(intrathecally) for each three groups 5 minutes prior to surgery)
  Intervention: Drug: placebo(distilled water)
• Active Comparator: magnesium sulphate
  Ninety patients 20-60 yr old American Society of Anesthesiologists ( ASA) physical status I or II, scheduled for femur surgery under spinal anesthesia, were studied in a prospective, double-blinded, randomized way. The patients were randomly allocated to one of three groups of 30 each. The magnesium group (groupM) received bupivacaine 15mg combined with 0.5ml magnesium 10%,The fentanyl group (group F) received bupivacaine 15mg combined with0.5 ml fentanyl[25microgram] and The placebo group (group P) received bupivacaine 15mg combined with 0.5ml distilled water(intrathecally) for each three groups 5 minutes prior to surgery)
  Intervention: Drug: magnesium sulphate

Inclusion Criteria:

.patients with American Society of Anesthesiologists(ASA) physical status I and

II, undergoing elective femur surgery

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Exclusion Criteria:

• significant coexisting disease such as hepato-renal and cardiovascular disease
• any contraindication to regional anesthesia such as local infection or ````bleeding disorders
• allergy to opioids
• long-term opioid use
• history of chronic pain.