Armstrong R F, Walker J S, Andrew D S, Cobbe S M, Cohen S L, Lincoln J C
Lancet. 1978 Mar 25;1(8065):632-4. doi: 10.1016/s0140-6736(78)91138-8.
The development of a miniature polarographic electrode mounted in the tip of a double-lumen plastic catheter has made possible continuous in-vivo monitoring of oxygen tension. Inexpensive catheters of this type have already proved of value as a means of continuously monitoring arterial oxygen tension in the newborn. In 25 patients with acute respiratory failure we found that these catheters could be safely and easily flow-guided into the pulmonary artery. In this way continuous recordings of mixed venous oxygen tension (PvO2) could be made for a period of several days. In our experience a sustained fall of PvO2 below 40 mm Hg proved to be a reliable indicator of respiratory or cardiac deterioration not always obvious by observation. In the patients described, falls of this order were seen after reductions in inspired oxygen concentration, in acute respiratory failure, in accidental underventilation, and in hypovolaemia and cardiac arrythmias. In some very ill patients routine nursing care involving movement of the patient caused pronounced falls of PvO2. Although electrode drift was an occasional problem, this could be checked by intermittent blood-sampling and recalibration if necessary.
安装在双腔塑料导管尖端的微型极谱电极的研制，使得对氧张力进行连续的体内监测成为可能。这种价格低廉的导管已被证明作为一种连续监测新生儿动脉氧张力的手段是有价值的。在25例急性呼吸衰竭患者中，我们发现这些导管能够安全、轻松地通过血流引导进入肺动脉。通过这种方式，可以连续数天记录混合静脉氧张力（PvO2）。根据我们的经验，PvO2持续降至40 mmHg以下被证明是呼吸或心脏功能恶化的可靠指标，而这种恶化通过观察并不总是明显的。在所描述的患者中，在吸入氧浓度降低、急性呼吸衰竭、意外通气不足、低血容量和心律失常后，出现了这种程度的下降。在一些病情非常严重的患者中，涉及患者移动的常规护理会导致PvO2显著下降。尽管电极漂移偶尔会成为一个问题，但如有必要，可以通过间歇性采血和重新校准来检查。
