| Gas Exchange during Apneic Oxygenation. |
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Yong Seok Oh, Myung Won Cho, Chung Lee |
1Department of Anesthesiology, College of Medicine, Seoul National University, Seoul, Korea.
2Department of Anesthesiology, College of Medicine, Han Yang University, Seoul, Korea. |
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| Abstract |
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Arterial and mixed venous blood gases were investigated during apnea in anesthetized paralyzed mongrel dogs. Dogs were ventilated with 100% oxygen after endotracheal intubation by intermittent positive pressure ventilation over 30 minutes before apnea. Femoral artery was cannulated for arterial blood gas analysis and Swan-Ganz catheter was inserted through femoral vein to draw mixed venous blood for gas analysis. In group 1 (n=6), the endotracheal tube was left open to room air during apnea and blood gas analysis were measured at 1 minute interval. In group 2 (n=6), the endotracheal tube was left connected to the respirator with 100% oxygen with 1 L/kg/min flow during apnea and blood gas analysis were checked at 5 minute interval. Blood sampling was continued until cardiac problem occured. In group1, PaO2,fall rapidly below 100 mmHg in 5 minutes and PaCO2, increased by the rate of 5.2 mmHg/min, In group 2, PaO2, fall slowly in proportion to increase of PaCO2, that rised in the rate of 4.1 mmHg/min, but hypoxemia does not occured until 45 minutes. In conclusion, arterial oxygenation can be maintained for long duration with oxygen flow through endotracheal tube but arterial carbon dioxide tension increase continuously during apnea. Useful methods to avoid carbon dioxide accumulation should be sought and investigated for clinical use of apneic oxygenation. |
| Key Words:
Apneic oxygenation; Continuous oxygen flow; Blood gas analysis; arterial; mixed venous |
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