The long-term use of magnesium has an effect on the skeletal muscle cells and the neuromuscular junctions.

• Project/Area Number: 13671572
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Anesthesiology/Resuscitation studies
• Research Institution: Nagoya University
• Principal Investigator: SATO Kosei Nagoya University, University Hospital, Research Associate, 医学部附属病院, 助手 (10235343)
• Co-Investigator(Kenkyū-buntansha): NISHIWAKI Kimitoshi Nagoya University, University Hospital, Assistant Professor, 医学部附属病院, 講師 (10189326)
• Project Period (FY): 2001 – 2002
• Project Status: Completed (Fiscal Year 2002)
• Budget Amount: ¥3,500,000 (Direct Cost: ¥3,500,000); Fiscal Year 2002: ¥1,700,000 (Direct Cost: ¥1,700,000); Fiscal Year 2001: ¥1,800,000 (Direct Cost: ¥1,800,000)
• Keywords: magnesium / neuromuscuiar blocking drug / succinylcholine / acetylcholine receptor

Research Abstract

We examined the serial electrolytes levels before and after rapid sequence induction of general anesthesia for cesarean section prospectively. 52 parturients scheduled for cesarean section under general anesthesia were enrolled into the study. After arterial cannulation and the measurements of blood electrolytes, patients were pretreated with vecuronium (0.5mg). Anesthesia was induced using sodium thiamylal (200mg) and succinylcholine (lOOmg) intravenously, and the trachea was rapidly intubated. Blood samples were obtained 2.5min. 5min. and lOmin. after administration of succinylcholine, then whole blood ionized electrolytes were analyzed.
Patients were devided into 4 groups by the use of tocolytic agent and the treatment period before surgery. Group 1 patients were treated with ritodrine and magnesium for more than 1 week (RITODRINE+Mg>1W, n=5), Group2 patients were treated with ritodrine and magnesium for less than 1 week (RITODRINE+Mg<1W, n=5), Group3 patients were treated with only ritodrine (RITODRINE, n=28), Group4 patients were not treated with tocolytic agent (CONTROL, n=14).
The serum potassium concentrations acquired before and 2.5min. after administration of succinylcholine were 4.0±0.6, 6.3±0.9 in Group 1, 3.5±0.2, 4.3±0.6 in Group2, 3.7±0.4, 4.1±0.9 in Group3, 3.8±0.2, 3.8±0.3 in Group4, respectively. Anesthetic induction with ketamine and vecuronium made no hyperkalemic reactions. A positive direct linear correlation between the duration of action of vecuronium and magnesium ion concentration was noted.
We have attempted to establish the chronic haypermagnesmia rat model with the use of a micro-osmotic pump for histological studies. It has been very difficult to maintain the intended concentration of magnesium ion by using the pump. We should make a major breakthrough to establish the hypermagnesemia rat model.