1. Changes in cerebrospinal fluid magnesium levels in patients undergoing spinal anaesthesia for hip arthroplasty: does intravenous infusion of magnesium sulphate make any difference? A prospective, randomized, controlled study 
M. Mercieri, R.A. De Blasi, S. Palmisani, S. Forte, P. Cardelli, R. Romano, G. Pinto, R. Arcioni 
British Journal of Anaesthesia 
Volume 109, Issue 2, Pages (August 2012)
DOI: /bja/aes146
Copyright © 2012 The Author(s) Terms and Conditions

2. Fig 1
Study protocol. At each time point, a 3 ml blood sample and a 0.5 ml CSF sample were collected. The initial 1 ml of each CSF sample was discarded to account for dead space in the catheter and to avoid possible dilution artifacts. The i.v. MgSO4 bolus was given at a dose of 50 mg kg−1 and was followed by a continuous infusion at 15 mg kg−1 h−1. The control group underwent the same protocol, but with normal saline (NS) instead of MgSO4.
British Journal of Anaesthesia  , DOI: ( /bja/aes146)
Copyright © 2012 The Author(s) Terms and Conditions

3. Fig 2
Flow chart for the assessed patients and randomized participants.
British Journal of Anaesthesia  , DOI: ( /bja/aes146)
Copyright © 2012 The Author(s) Terms and Conditions

4. Fig 3
(a) Changes in serum total [Mg] and ionized [Mg2+] Mg concentrations in both groups. In the Mg group, serum [Mg] peaked at T4 and increased by 80% from baseline. Ionized Mg levels underwent the same changes over time. In the control group, serum total [Mg] slowly decreased and the change became significant at T5, when the 6 h MgSO4 infusion ended. (b) The changes in total and ionized CSF Mg levels in both groups. After spinal anaesthesia, total and ionized CSF Mg concentrations decreased by about 10% from baseline and at T5 returned to baseline in both groups. Ionized and total Mg concentrations underwent similar changes over time, in both serum and CSF, confirming that total Mg concentration accurately reflects concomitant changes in the ionized fraction.4 *P<0.05, **P< No significant differences were found at each time point between the groups, except for serum Mg in the Mg group with respect to the control group.
British Journal of Anaesthesia  , DOI: ( /bja/aes146)
Copyright © 2012 The Author(s) Terms and Conditions