Wu E Y, Barazanji K W, Johnson R L
Department of Internal Medicine, University of Texas, Southwestern Medical Center, Dallas 75235, USA.
J Appl Physiol (1985). 1997 Jan;82(1):196-202. doi: 10.1152/jappl.1997.82.1.196.
We studied the effects of time delay on blood gases, pH, and base excess in blood stored in glass and plastic syringes on ice and the effects of resulting errors on calculated alveolar-to-arterial PO2 difference (A-aDO2). Matched samples of dog whole blood were tonometered with gas mixtures of 5% CO2-12% )2-83% N2 (mixture A), 10% CO2-5% O2-85% N2 (mixture B), and 2.88% CO2-4% O2-93.12% N2 (mixture C). Tonometered blood samples were transferred to 5-ml glass (5G), 5-ml plastic (5P), and 3-ml plastic (3P) syringes and stored on ice. Blood gases were measured every 1 h up to 6 h. In 5G, PO2 progressively decreased in blood tonometered with mixture A but rose in blood tonometered with mixtures B and C. O2 saturation progressively fell in all cases. In 5G, blood PCO2 progressively rose regardless of which gas mixture was used, and pH as well as base excess progressively fell. The rise in PO2 was faster in plastic than in glass syringes, and O2 saturation always rose in plastic syringes. Differences between storage in plastic and glass syringes on PO2 change were greatest when initial blood PO2 was highest (mixture A). At the highest PO2, O2 exchange was faster in 3P than in 5P. The rise of PCo2 was just as fast in plastic as in glass syringes, but in both the rise in PCO2 was faster at a higher initial PCO2 (mixture B) than in lower initial PCO2 (mixtures B and C). Rates of PO2 and PCO2 change in matched samples were significantly faster in 3P than in 5P. Errors due to rises in PCO2 and PO2 cause additive errors in calculated A-aDO2, and when blood is stored in plastic syringes for > 1 h significant errors result. Errors are greater in normoxic blood, in which estimated A-aDO2 decreased by > 10 Torr after 6 h on ice in plastic syringes, than in hypoxic blood.
我们研究了时间延迟对储存在玻璃和塑料注射器中并置于冰上的血液的血气、pH值和碱剩余的影响，以及由此产生的误差对计算得出的肺泡 - 动脉血氧分压差（A-aDO2）的影响。将犬全血的配对样本用5%二氧化碳 - 12%氧气 - 83%氮气（混合气A）、10%二氧化碳 - 5%氧气 - 85%氮气（混合气B）和2.88%二氧化碳 - 4%氧气 - 93.12%氮气（混合气C）的气体混合物进行血气测定。经血气测定的血样被转移至5毫升玻璃注射器（5G）、5毫升塑料注射器（5P）和3毫升塑料注射器（3P）中，并置于冰上保存。每1小时测量一次血气，直至6小时。在5G注射器中，用混合气A进行血气测定的血液中PO2逐渐降低，但用混合气B和C进行血气测定的血液中PO2升高。在所有情况下，氧饱和度均逐渐下降。在5G注射器中，无论使用哪种气体混合物，血液PCO2均逐渐升高，pH值和碱剩余则逐渐下降。塑料注射器中PO2的升高速度比玻璃注射器中快，且塑料注射器中的氧饱和度始终升高。当初始血液PO2最高（混合气A）时，塑料和玻璃注射器储存时PO2变化的差异最大。在最高PO2时，3P注射器中的氧交换比5P注射器快。塑料注射器中PCO2的升高速度与玻璃注射器中一样快，但在两种注射器中，初始PCO2较高（混合气B）时PCO2的升高速度比初始PCO2较低（混合气A和C）时快。配对样本中PO2和PCO2的变化率在3P注射器中比在5P注射器中明显更快。PCO2和PO2升高导致计算A-aDO2时产生累加误差，当血液在塑料注射器中储存超过1小时会产生显著误差。常氧血中的误差比低氧血中的误差更大，在塑料注射器中冰上保存6小时后，常氧血中估计的A-aDO2降低超过10托。
