RESUMO
BACKGOUND: During apnea, as in any other acid-base disturbance, ion exchanges between intra- and extracellular compartments are expected, but few studies have reported such findings. The purpose of this study was to observe serum sodium, potassium, chloride and bicarbonate concentrations during apnea until death. METHODS: Seventeen New Zealand White Rabbits (weight 2.0~3.0 kg) were subjected to apneic oxygenation. Then we measured heart rate, blood pressure, intracranial pressure, arterial blood gas analyses and serum electrolytes (sodium, potassium, chloride and bicarbonate) concentrations during apnea until death. RESULTS: Heart rate decreased because of sinus bradyarrythmia at 10 minutes after apnea and thereafter continued to increase. Blood pressure increased up to 30 minutes after apnea and thereafter continued to decrease. Intracranial pressure consistently increased during apnea. Serum bicarbonate and chloride ion concentrations showed reciprocal changes, but there was no significant correlation. Serum sodium and potassium concentrations increased up to 40 minutes and 30 minutes respectively, and thereafter decreased until death. All serum ion concentrations were within normal limits. CONCLUSION: The serum sodium, potassium, chloride and bicarbonate concentrations were maintained within normal limits during apneic oxygenation until death.