Luks F I, Johnson B D, Papadakis K, Traore M, Piasecki G J
Division of Pediatric Surgery, Brown University School of Medicine, Providence, RI, USA.
J Pediatr Surg. 1998 Aug;33(8):1297-301. doi: 10.1016/s0022-3468(98)90173-7.
BACKGROUND/PURPOSE: The choice of monitoring parameters in fetal surgery has thus far been based on feasibility rather than on predictability. Ideally, monitoring should be noninvasive, have a rapid response time and high sensitivity, and be applicable to open and endoscopic techniques. Herein, the authors studied the response of several parameters to standardized episodes of fetal ischemia and stress.
Eight time-dated fetal lambs (110 days, term, 145 days) were used. Under general anesthesia, a balloon occluder was placed around the umbilical cord. Pulse oximetry (POx + heart rate, HR), electrocardiography (ECG), direct oximetry (DOx), and blood pressure (BP) were recorded continuously. After stabilization, the umbilical cord was completely occluded for 5 seconds, then released. False-negative recordings were defined as failure of a parameter to respond to umbilical occlusion; false-positive episodes were defined as 10% change in value over < or = 10 seconds during stabilization (baseline) period.
The fetuses were monitored for an aggregate of 358 minutes. Baseline DOx was 64%+/-5%, POx, 66%+/-16%; HR, 141+/-18 beats per minute (bpm); systolic BP (SBP), 51+/-3 torr; and diastolic BP (DBP), 38+/-2 torr. During umbilical occlusion (n=15), SBP increased to 56+/-3 torr and DBP to 43+/-2 torr at 0.5 seconds, then returned to baseline at 8.0 seconds. A decrease was seen in DOx (start at 3.5s, maximum delta 9.9+/-1.5% at 10.5 seconds) and POx (start at 4.2 seconds, maximum delta 7.3+/-2.4% at 20.5 seconds). Heart rate showed <10% decrease (start at 8.5 seconds, nadir 131+/-14 bpm at 19.5 seconds). No ECG changes were noted. Sensitivity was 100% for DOx, POx, and BP, but only 14% for HR; specificity was 97% for DOx and 88% for POx; positive predictive value was 58% for DOx and 37% for POx; negative predictive value was 100% for DOx and POx.
Direct intravascular oximetry and blood pressure provide a prompt and reliable response to acute fetal stress, but are too invasive for routine use. Bradycardia is an insensitive and late sign of fetal distress. Pulse oximetry has a rapid response time (<5 seconds), high sensitivity, and negative predictive value. In addition, its application is noninvasive and has proven to be feasible in open and endoscopic fetal surgical procedures. It therefore appears to be the monitoring parameter of choice for fetal surgery.
背景/目的：迄今为止，胎儿手术中监测参数的选择是基于可行性而非可预测性。理想情况下，监测应是非侵入性的，具有快速的反应时间和高灵敏度，并且适用于开放手术和内镜技术。在此，作者研究了几个参数对胎儿缺血和应激标准化发作的反应。
使用了8只不同孕周的胎羊（110天、足月、145天）。在全身麻醉下，在脐带周围放置一个球囊阻塞器。连续记录脉搏血氧饱和度（POx + 心率，HR）、心电图（ECG）、直接血氧饱和度（DOx）和血压（BP）。稳定后，脐带完全阻塞5秒，然后松开。假阴性记录定义为参数对脐带阻塞无反应；假阳性发作定义为在稳定（基线）期内10秒内数值变化<或 = 10%。
对胎儿总共监测了358分钟。基线时DOx为64%±5%，POx为66%±16%；HR为141±18次/分钟（bpm）；收缩压（SBP）为51±3托；舒张压（DBP）为38±2托。在脐带阻塞期间（n = 15），SBP在0.5秒时升至56±3托，DBP升至43±2托，然后在8.0秒时恢复到基线。DOx（在3.5秒开始，在10.5秒时最大变化量为9.9±1.5%）和POx（在4.2秒开始，在20.5秒时最大变化量为7.3±2.4%）出现下降。心率下降<10%（在8.5秒开始，在19.5秒时最低点为131±14 bpm）。未观察到ECG变化。DOx、POx和BP的灵敏度为100%，但HR仅为14%；DOx的特异性为97%，POx为88%；DOx的阳性预测值为58%，POx为37%；DOx和POx的阴性预测值为100%。
直接血管内血氧饱和度测定和血压对急性胎儿应激提供了迅速而可靠的反应，但侵入性太强，不适合常规使用。心动过缓是胎儿窘迫的不敏感和晚期征象。脉搏血氧饱和度测定具有快速的反应时间（<5秒）、高灵敏度和阴性预测值。此外，其应用是非侵入性的，并且已证明在开放和内镜胎儿手术中是可行的。因此，它似乎是胎儿手术监测参数的首选。
