title: Effect of addition of magnesium to local anesthetics for peribulbar block: A prospective randomized double-blind study.
abstract: BACKGROUND
  Magnesium sulphate has been used along with local anesthetics in different regional blocks and found to be effective in decreasing the time of onset of the block and increasing the duration of the block.
  
  
  OBJECTIVE
  To evaluate the effect of addition of magnesium sulfate to standard local anesthetics mixture on the time for onset of the globe and lid akinesia for peribulbar block in ophthalmic surgeries.
  
  
  METHODS
  Sixty patients with American Society of Anesthesiologists status I to III undergoing ophthalmic surgery under peribulbar block were included in this study. Patients were randomized into two groups. Both the groups received 4.5 ml of 2% lidocaine, 4.5 ml of 0.5% bupivacaine with150 IU hyaluronidase. Group NS received normal saline 1 ml in the peribulbar block and Group MS, magnesium sulfate 50 mg in 1 ml normal saline. The onset of akinesia, satisfactory block and complications were observed by an independent observer.
  
  
  RESULTS
  Demographic data was statistically similar. In the Group NS at 3, 5, 10 and 15 min after the block, complete akinesia was seen in 0, 2, 11 and 28 patients respectively. In the Group MS, at 3, 5, 10 and 15 min after the block, complete akinesia was seen in 13, 23, 27 and 28 patients respectively. Patients received magnesium sulfate showed the statistically significant rapid onset of lid and globe akinesia than the control group till 10 min (P < 0.000). None of the patients needed a supplementary block and had complications during the surgery.
  
  
  CONCLUSIONS
  Addition of 50 mg of magnesium sulfate to the lidocaine-bupivacaine mixture for peribulbar block decreases the onset of akinesia without any obvious side effect.
authors.affiliation: Department of Anesthesiology, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: R
authors.initials: R
authors.lastname: Sinha
authors.affiliation: Department of Anesthesiology, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: A
authors.initials: A
authors.lastname: Sharma
authors.affiliation: Department of Anesthesiology, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: B R
authors.initials: BR
authors.lastname: Ray
authors.affiliation: Department of Anesthesiology, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: R
authors.initials: R
authors.lastname: Chandiran
authors.affiliation: Department of Anesthesiology, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: C
authors.initials: C
authors.lastname: Chandralekha
authors.affiliation: Department of Ophthalmology, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: R
authors.initials: R
authors.lastname: Sinha
keywords: Adjuvants; akinesia; analgesia; magnesium sulfate; peribulbar block