Plasma ionized magnesium during acute hyperventilation in humans
G Hafen1, R Laux-End, A C Truttmann
1Department of Pediatrics, University of Berne, Switzerland.
Clinical Science (London, England : 1979)
|September 1, 1996
Summary
Respiratory alkalosis from overbreathing reduces ionized magnesium levels. This may explain tetany and cardiac issues linked to hyperventilation, highlighting magnesium
Area of Science:
- Cardiology
- Physiology
- Biochemistry
Background:
- Respiratory alkalosis is linked to tetany, cardiac arrhythmias, and coronary vasoconstriction.
- Magnesium is crucial for membrane function; depletion is associated with cardiac issues.
- New magnesium-selective electrodes allow measurement of circulating ionized magnesium.
Purpose of the Study:
- To investigate the effect of induced respiratory alkalosis on circulating ionized magnesium levels.
- To determine if hyperventilation alters total plasma magnesium or ionized magnesium fractions.
Main Methods:
- Eight healthy subjects voluntarily overbreathed for 30 minutes to induce respiratory alkalosis.
- Total plasma magnesium, ionized magnesium, and free magnesium fractions were measured.
- Relative intravascular magnesium mass was calculated using plasma magnesium and hematocrit.
Main Results:
- Hyperventilation did not alter total plasma magnesium concentration.
- Ionized magnesium concentration significantly decreased by 0.05 mmol/l (median).
- The free magnesium fraction and relative intravascular magnesium mass also significantly decreased.
Conclusions:
- Acute overbreathing reduces circulating ionized magnesium concentration and intravascular magnesium mass.
- Extracellular magnesium deficiency may contribute to tetany and cardiac complications during hyperventilation.
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