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Changes of Heart Rate, Blood Pressure, and Plasma Catecholamine Levels in Rabbits during the Apneic Oxygenation
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Seung Eun Oh, Hyun Jeong Kim, Kwang Won Yum
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Korean J Crit Care Med. 2001;16(1):30-35.
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Abstract
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- BACKGROUND
Permissive hypercapnia and apneic oxygenation are used to provide oxygen to patient without active ventilation. It is well known that hypercapnia induces the release of endogenous catecholamines. However, it is unclear that how much or what kind of catecholamines are released.
The aim of this study was to observe changes of basic hemodynamic parameters and plasma catecholamine concentration during apneic oxygenation. METHODS Twenty-one rabbits weighing 2.0~3.0 kg were anesthetized with 100% oxygen and isoflurane. 0.05 mg/kg of atropine was injected and endotracheal intubation was done.
1 mg/kg/hr of vecuronium was infused during the experiment.
The anesthesia and apneic oxygenation was maintained with 100% oxygen and 2 vol% isoflurane under 1 cmH2O PEEP using continuous positive airway pressure device. During the apneic oxygenation, blood pressure, heart rate, and plasma catecholamine concentration were measured every 10 min using High Performance Liquid Chromatography. RESULTS Systolic blood pressure was significantly increased but diastolic blood pressure was not changed until post-apneic 40 min. After then, both systolic and diastolic blood pressure were significantly decreased. At post-apneic 10 min, heart rate was dramatically decreased and slowly recovered to the level of control data until post-apneic 60 min. Plasma epinephrine level was increased higher than that of norepinephrine by 3 to 4 times. CONCLUSIONS Epinephrine may play more important role than norepinephrine to compensate the cardiovascular depressive effects of hypercapnia during the apneic oxygenation in rabbits.
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Changes of Sodium, Potassium, Chloride and Bicarbonateion Concentrations in Apneic Rabbits
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Hyun Jung Kim, Kwang Won Yum, Yong Rak Kim
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Korean J Crit Care Med. 1998;13(2):186-193.
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Abstract
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- 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.
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