摘要
新生儿窒息是指出生时无呼吸或呼吸抑制,是导致全世界新生儿死亡、脑瘫和智力低下的主要原因之一。新生儿窒息导致的死亡,已占到婴儿死亡的20%~30%。新生儿窒息缺氧时,主要表现为呼吸障碍,往往先有过度呼吸,初起 1~2 分钟有呼吸深快,如缺氧未及时纠正,旋即转为呼吸抑制和反射性心率减慢,此为原发性呼吸暂停;此时患儿肌张力存在,血管轻微收缩,血压升高,循环尚好,但有紫绀,如及时给氧或予以适当刺激,有时甚至在无外界帮助下仍能恢复呼吸。如缺氧持续存在,则出现喘息样呼吸,心率继续减慢,血压开始下降,肌张力消失,苍白,呼吸运动减弱,最终出现一次深度喘息而进入继发性呼吸暂停,如无外界正压呼吸帮助则无法恢复而死亡。上世纪 50 年代 Apgar根据新生儿窒息临床表现提出用皮肤颜色、心率、肌张力、呼吸等五项评判新生儿窒息程度的方法,用于区别窒息程度, 每项 0~2 分,总共 10 分;评分越高,表示窒息程度越轻;0~3 分为重度窒息;4~7 分为轻度窒息;8~10 分为正常。几十年来 Apgar 评分对新生儿窒息复苏提供了简便有效的方法。但近年来人们逐渐认识到五项中除心率是客观指标,其余四项都带有主观性,易造成误诊。
窒息的本质是缺氧酸中毒引起的的器官功能或器质性损伤,缺氧酸中毒必然引起血气变化,可通过血气分析反映出来,脐动脉血血气分析可直接反映胎儿娩出时的酸碱平衡状态,为帮助诊断新生儿窒息提供了更为客观的方法。国外学者近年来在脐动脉血气方面进行了大量的研究。美国妇产学会已把脐动脉血气 p H 值作为诊断新生儿窒息的诊断标准之一。随着便携式血气分析仪的使用,国内有学者亦对此进行了一些研究,但我国目前尚未把脐动脉血气作为诊断新生儿窒息的标准,因此目前仍沿用传统的 Apgar 评分。窒息儿的预后一直是人们关注的重点,有研究表明脐血 p H 值与预后有依存关系。运用脐血血气分析早期预测围产儿缺氧缺血,与 Apgar 评分互补,可提高围生期窒息诊断的准确率,有利于降低围产儿死亡率及智力残疾的发生,提高出生人口素质。 基于以上认识我们随机对本院娩出的 344 例新生儿立即进行脐动脉血气分析;新生儿娩出后未啼哭前夹住近胎儿端的一段脐带约 15cm,使之与胎盘及新生儿循环隔绝,这段脐血血气由于在未建立自主呼吸前取样,可以客观反映胎儿血气变化结局;并常规对娩出新生儿进行 Apgar 评分,通过分析脐动脉血血气、Apgar 评分在判断新生儿窒息及预后的临床意义,为脐动脉血气分析在临床应用提供实验依据。
窒息是导致全世界新生儿死亡、脑瘫和智力低下的主要原因之一。估计全世界每年400万新生儿死亡中有23%以及在死亡年龄<5岁的儿童中有8%与出生时的窒息有关。即使是在发达国家的转诊中心,中、重度HIE仍有54-62%会发生死亡或导致中、重度残疾。根据我国妇幼卫生监测显示2000年我国5岁以下儿童前三位死亡原因为肺炎、出生窒息、早产或低出生体重儿,新生儿窒息为第二死因,在城市感染性疾病得以控制后出生窒息已成为第一位死因。2005年前三位死因为早产、出生窒息及肺炎,窒息仍为第二死因。
新生儿窒息可引起多脏器缺氧缺血性损害,细胞能量代谢衰竭,乳酸积聚,可导致细胞内酸中毒和细胞离子泵功能受损,钙离子内流,氧自由基大量生成,损伤细胞膜、蛋白质和核酸,致使细胞的结构和功能破坏,出现多脏器功能损害。其中以脑、心、肾、肺、代谢为多见。早期发现脑心损伤,及时治疗、早期干预,对降低围生儿的致残率和死亡率,提高人口质量具有重要意义。虽然随着医疗技术水平的发展,现代新生儿抢救技术在不断的提高,新生儿死亡率、致残率有了一定程度的下降,但新生儿窒息后多脏器损害的发生率仍相当高,存活的新生儿常有不同程度的神经系统发育障碍,对家庭乃至社会的负担都是巨大的。本文结合新生儿窒息原因的分析、胎儿窘迫与新生儿认知水平之间关系的研究,提出防护和减少窒息现象的有效措施。
Abstract
Neonatal asphyxia is pointed out that without breathing or breathing inhibition, is lead to neonatal death around the world, one of the leading causes of cerebral palsy and mental retardation. Neonatal suffocation deaths, has accounted for 20% ~ 30% of infant deaths. Neonatal asphyxia anoxia, main show is respiratory disorder, often have excessive breathing first, beginning of 1 ~ 2 minutes have deep breathing fast, such as oxygen not timely rectification, promptly to reflex slow heart rate, respiratory depression and this is a primary apnea; The children muscle tension exists, vascular mild contraction, blood pressure increases, the cycle is still good, but there are purple purple, such as giving oxygen or stimulation of appropriately, sometimes even without outside help can still restore breathing. Persist, such as oxygen, appear breathing breathing, heart rate continues to slow down, and began to fall blood pressure, muscle tension, pale, respiratory motion is abate, eventually appeared a deep breathing into the secondary apnea, if there is no outside positive pressure breathing help cannot recover and death. Apgar in the 1950 s, according to neonatal asphyxia clinical manifestation with skin color, breathing, heart rate, muscle tension and so on five to judge the degree of neonatal asphyxia, used for the difference degree of asphyxia, each 0 to 2 points, a total of 10 points; The higher the score, the lighter said asphyxia degree; 0 ~ 3 into severe asphyxia; 4 ~ 7 divided into mild asphyxia; 8 ~ 10 were divided into normal. For decades, Apgar score of neonatal asphyxia recovery provides a simple and effective method. But in recent years, people gradually realized that among the five heart rate is an objective indicator, the remaining four are subjective, easy misdiagnosis.
Asphyxia is the essence of hypoxia acidosis caused by organ or physical damage, hypoxia acidosis is bound to cause blood gas changes, can be reflected through the blood gas analysis, umbilical artery blood gas analysis can directly reflect the acid-base equilibrium when fetal childbirth, to help in the diagnosis of neonatal asphyxia provides more objective method. Foreign scholars in recent years, a lot of research in terms of umbilical arterial blood gas. The American society of obstetrics and gynecology has the umbilical arterial blood gas p H value a