Schram C M, Gardosi J O
Department of Obstetrics and Gynaecology, University of Nottingham, United Kingdom.
Am J Obstet Gynecol. 1994 Apr;170(4):1174-7. doi: 10.1016/s0002-9378(94)70117-2.
We wished to investigate the effect of caput succedaneum on pulse oximetry readings.
Oxygen saturation was measured by reflection pulse oximetry on various sites of scalps of 18 healthy neonates. The pulse rate obtained from the oximeter was checked against the heart rate from the electrocardiogram to see whether they were in agreement and synchronized.
Nonsynchronized saturation values had a much wider range (30 to 97 vs 70 to 98) and a significantly lower mean (70 vs 84) than did synchronized values. Synchronized readings were obtainable in all 18 subjects over the temporal region but in only 39% of cases over the occipital region. Fourteen neonates had caput succedaneum, and in nine (61%) of these synchronized readings were not possible. It was noted that falsely low saturation values can be derived from pulsating waveforms, which have a slower rate than the electrocardiogram rate.
The observed low pulsation rate is either of venous origin or represents modulated transmission of arterial signal through an edematous or congested scalp. This artifact will result in nonarterial oxygen saturation readings, and its exclusion is of importance in the development of pulse oximetry for intrapartum monitoring of the fetus.
我们希望研究头皮水肿对脉搏血氧饱和度读数的影响。
通过反射式脉搏血氧饱和度仪对18名健康新生儿头皮的不同部位进行血氧饱和度测量。将血氧饱和度仪测得的脉搏率与心电图测得的心率进行比对，以查看二者是否一致且同步。
与同步值相比，非同步饱和度值的范围要宽得多（30至97对70至98），且平均数值显著更低（70对84）。在所有18名受试者的颞部区域均可获得同步读数，但在枕部区域只有39%的情况能获得同步读数。14名新生儿有头皮水肿，其中9名（61%）无法获得同步读数。值得注意的是，脉动波形可能会得出错误的低饱和度值，其速率比心电图速率要慢。
观察到的低脉动率要么源于静脉，要么代表动脉信号通过水肿或充血头皮的调制传输。这种伪差会导致非动脉血氧饱和度读数，在开发用于产时胎儿监测的脉搏血氧饱和度测定法时，排除这种伪差很重要。
