MAGNESIUM DISCUSSION PRO AND CON

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MAGNESIUM DISCUSSION PRO AND CON
Eugene Yevstratov MD

• MAGNESIUM SHOULD BE ADMINISTERED TO ALL CORONARY
  ARTERY BYPASS GRAFT SURGERY
• PATIENTS UNDERGOING
• CARDIOPULMONARY BYPASS ?

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Mg as an element

• Cofactor for more than 260 enzymes
• Required for oxidative metabolism
• Required for protein syntesis
• Required for maintenace of ion cell balance
• A normal function of ion pumps

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Mg administration (pro)

• Eliminate the deleteriouse effects of
  hypomagnesemia (a common, often unrecognized
  condition in cardiac surgical patients)
• Decrease myocardial insult induced during aortic
  crossclamp
• Decrease the incidence of postoperative
  arrhythmias

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Some effects of myocardial ischemia and
reperfusion

• Increased intracellular calcium
• Production of oxygen derived free radicals
• Depletion of high energy phosphates

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Mg action site

• Magnesium is an inorganic calcium channel blocker
• Magnesium blocks reperfusion indused free radical
  formation
• Magnesium reduce the myocardial insult during an
  ischemia reperfusion sequence
• Magnesium as a cellular cofactor help unto
  myocardial cell to reestablish oxidative
  metabolism and replenish high energy phosphate
  stores
• Magnesium ATP complex is olso the substrate for
  enzymatic reactions underlying muscule
  contraction and relaxation.

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Antiarrhythmic value

• Is important in maintaining the ionic balance
  across the cell membrane
• During ischemia prevents the detrimental
  intracellular potassium efflux and calcium efflux
• A key ion in maintaining the cellular ionic
  gradients
• Accepted as a treatment for ventricular
  tachycardia, torsade de points, supraventricular
  arrhythmias, including atrial fibrilation

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Magnesium

• Readily available
• Easily administered
• Inexpensive

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Magnesium (con)

• Muscle paralysis compromising respiratory
  function or delaying extubation
• Sedation and confusion
• Hypotension
• Increased posoperative bleeding as result of
  inhibition of platlet function
• Increased energy requirement for defibrilation
  after intraoperative magnesium supplementation

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The End
November 2002
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