(3)胎児脳機能障害の評価法に関する研究(シンポジウム3「新生児脳障害の減少に向けて」,<特集>第62回日本産科婦人科学会・学術講演会)

概要

論文の詳細を見る
According to Lorenz, it is possible to make valid assumptions about brain function from observed behavior. Investigation of the central nervous system (CNS) in developing animals has shown that anatomical function occurs first in the caudal segments, then in the rostral segments, similar to the development of the spinal cord followed by the brainstem. Several investigators have suggested that anatomical defects are manifested as functional defects. During the last 20 years, real-time ultrasound has facilitated in vivo observation of human fetal movements, and behavioral patterns in utero can be assessed as a one-to-one match between manifestation of an individual activity and a corresponding CNS function. However, to date, no generalized antenatal screening system for fetal CNS function has been developed and validated. In our previous paper, we noted that such screening of 1,426 fetuses later delivered between 37 and 41 weeks of gestation identified 24 cases as suspicious for impairment. Of the 24 fetuses, 10 were chosen at 35〜36 weeks of gestation to undergo the second step of "extensive ultrasound observation," with this examination designed specifically to look for possible CNS functional impairment using five different behavioral patterns as indicators. Half of the tested fetuses (5/10) showed abnormal behavioral patterns before birth. However, use of this screening system is problematic for typical clinical practice. It involves a considerable investment of time, and decisions regarding the five indicators are complex. Thus, we decided to devise a method with a sufficiently short duration for examination that would be cost effective. We evaluated the "brief ultrasound examination" using results from normal cases. The median length of time required by normal cases to fulfill our criteria was 28 minutes (range, 11〜60 minutes). Next, we studied the five cases with abnormal behavior retrospectively. The median length of time required by these cases to fulfill our brief examination criteria was 50 minutes (range, 30〜60 minutes). The only case undetectable by this brief ultrasound examination had an eye-movement period significantly longer than the normal upper limit. Thus, we concluded that the accuracy of the brief ultrasound examination was sufficient for a screening examination. We devised a two-step prenatal screening system based on these results. In the first screening step, fetuses are considered to have potential impairment of in utero brain function when any of the following four indicators are observed: decreased or no fetal movement, persistent non-reactive fetal heart rate (FHR) pattern, polyhydramnios and/or CNS malformation. An attempt was also made to initiate an antenatal screening system to discriminate those fetuses with compromised CNS function from the general population. Fetuses selected in this way underwent further brief ultrasound examination, with observation of movement of the extremities, chest wall (breathing), eyes and mouth, followed by the five indicators. 1. Movement of extremities One episode of motion, involving extension, flexion, external and internal rotation, or abduction and adduction of all four extremities during the observation period was considered normal. 2. Breathing movement Breathing movement was considered normal if continuation of this movement for 30 seconds was observed at least once. 3. Alternation of the eye movement (EM) and no eye movement (NEM) periods The alternation of the EM and NEM periods was considered normal when both periods were longer than 5 minutes. 4. Rapid (REM) and slow (SEM) eye movement patterns REMs coexisting with SEMs were considered normal. 5. Concurrence of regular mouthing movement during the NEM period One episode of regular mouthing during the NEM period was considered normal. Prospectively, we noted that such screening of 4,978 fetuses later delivered between 32 and 41 weeks of gestation at Maternity and Perinatal Care Unit of Kyushu University Hospital in Japan identified 93 cases as suspicious for impairment. We assessed the correlation between intrauterine behavioral patterns and neonatal neurological outcome (MR, CP, low Developmental Quotient). Of the 93 fetuses, 26 were chosen at 35〜40 weeks of gestation to undergo the second step of the brief ultrasound examination. Based on these examinations, 10 cases had abnormal behavioral patterns during the intrauterine period. Eight of these 10 cases showed poor neurological outcomes. The two other cases showed normal neurological outcomes. Thus, this method has sufficient sensitivity. We conclude that the main contribution of this study is to establish a first clue to examine fetal CNS functional impairment, and we have demonstrated the possibilities of applying the screening system in a clinical setting. We think it is important for obstetricians to try this method.
2010-12-01

(3)胎児脳機能障害の評価法に関する研究(シンポジウム3「新生児脳障害の減少に向けて」,<特集>第62回日本産科婦人科学会・学術講演会)

スポンサーリンク

概要

著者

関連論文

スポンサーリンク