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Plasma ionized calcium in brain-dead patients

J P Fulgenico1, B Riou, C Devilliers

  • 1Département d'Anesthésie-Réanimation, Groupe Hospitalier Pitié-Salpêtrière, Université Paris VI, France.

Intensive Care Medicine
|October 1, 1995
PubMed

Insights

Hypocalcemia is uncommon and likely not the primary cause of myocardial dysfunction in brain-dead patients. Direct ionized calcium measurement is crucial for accurate assessment in these critical cases.

Area of Science:

  • Cardiology
  • Neurology
  • Critical Care Medicine

Background:

  • The mechanisms underlying myocardial dysfunction following brain death are not fully understood.
  • Hypocalcemia is a known cause of reversible myocardial dysfunction, but its prevalence and impact in brain death are unclear.

Purpose of the Study:

  • To investigate the incidence and effects of hypocalcemia on myocardial function in brain-dead patients.
  • To determine if hypocalcemia contributes significantly to myocardial dysfunction in this population.

Main Methods:

  • Plasma total and ionized calcium levels were measured in 54 brain-dead patients.
  • Cardiac function was assessed using echocardiography (left ventricular ejection fraction area - LVEFa) and QT intervals.
  • Dopamine requirements were recorded to evaluate hemodynamic support needs.

Main Results:

  • A significant decrease in total plasma calcium was observed in 91% of patients, but only 35% had low ionized calcium.
  • No significant differences in LVEFa or QT intervals were found between normocalcemic and hypocalcemic patients.
  • Hypocalcemic patients required higher dopamine doses, indicating reduced systemic vascular resistance.

Conclusions:

  • Decreased plasma ionized calcium is infrequent and typically not severe in brain-dead patients, suggesting it's not the main driver of myocardial dysfunction.
  • Hypocalcemia in brain death may be linked to decreased systemic resistance, necessitating increased vasopressor support.
  • Accurate assessment of calcium status in brain-dead patients requires direct measurement of ionized calcium.
Abstract

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