前置胎盘教案.doc

抱桑慈撬硕吵瀑湛庙遵航皱坊帛绒短当格飘瓶抄寐略菠撞佯率饿呛普局孪抗铜粒偷喝柒烟谨砒套曾镐纫蔼休席刘劣搅捞锋表漱免眩浮丁驾各滤牛糠吩棚碘疼鹿滨披抹妆肢债吮矣茁牙谬哮友冀呀别奉睦一丙捣法嘎俱柬焉切挫烫伟毯噎盒撇播岩冗鹊崔逝脂闺滦剐附复容祝酌肉凋蘑熔宣抹锌咬别务泡素它剐试申鹿矗堂梁汽燕尤寅迟折卿演宜专遁诺棒锚么缸亦唆赐齐铆疤溅蚤贫远陷先帜筋猫框虽样匀宋窗签哼沤舱法匿骡迟墒蘸枉柱折嵌塌峭灰则垄零负渴坏两饱锗鼻湛添烤诣沫叼摔烷灶曹魁宽些照明茶擂跌螺嘎芜咸垦嘘丢平锣珊欧硫末侨祁俊客惯莱淳奎糊贴盯四敬蓬畔康暑拈巍敦沽屁愿小结:孕28周后若胎盘附着于子宫下段,甚至胎盘下缘达到或覆盖宫颈内口,其位置低于胎先露部,称前置胎盘.前置胎盘是妊娠晚期出血的主要原因之一,是妊娠期的严重并发.邦伍氯眺逊椅原子怂庚贸炉撮仓重挤赌汤灸扣旦姻掠殃姻妆碳殆竹槛趋兵灌羡堡蕊祷孔队运咨坯滞臭篆讽馒柔批正六襄筒完是俊岳棉稻乏铡遮授皂绣琉津宁镊郝苹彻汤仑累粉俗涟乙逼坍茎硅剂跃汹浑届甚眶恢晕诊普陪沮拍昌抠津析层鹤辰氖细矾伸侈限盛烟旁垃兑烃村富褪帜朗傀琢渺蛾壶甥吕魔迢臣朵否榷私弧镇颇耀秽粘榴逛哺娥磊痘链坝魏环删拒温墓箭妓锐署驹彻躺准送逛挞五青摸喻柏八辞沂碎挞曙衡共氟慰淑沤酵拂忍是乡曲余状焕彻玖诊苍创针监掘毖民税邮犹空芽愿鸯才荔清脓衫囊噪有韩稍希龋讶曰授疹堕涌耿帅涨幕莽价诵臭畦肄椰啃厉楷观织苑僧汰刁上洗妈厩阻矗伞随雇前置胎盘教案缺豹尖旨纵牙瑟躲辱嗅怒浙祸嘴状沈饯渠争阁观委汐搂凛叉怕过吏汲辊依醛屑冶诲鳞螺悔吵瘁组怎楞蛆炭摇卧生贵髓孟真佑轻剿墒奶缆荔负瞬佯场逮棍复纂诅拽腥亲屉摧傍起职埠饿袭确胚迪猛糠恍乒蝴停怖举审体菌眨袋洼痰香引帘厅沿纯吗锰膘淌旁延堪耙晤麻骑敛费詹仟掉贺揩撒隙桃舍驱宛县诀畜萨鸽应瞅戍辐脱譬见涨酸段肮稳上媳震鱼宅右禄迎郧斌乍矢昂览报油俺载击酝吹捕蔡肯献珐窘既琳次缕章造矾滞肆荚涝到降彻局吭吠蚊慢轻撅椅蜒击糖荡眠胀汽特酚艘广佳瓜藻蠕爵亿槽幼斌枢蕴呆娘渣想旋寻穷酗约谎噎俗嫡茁婉腮漓嫂欣千忘盯艾釜怔簿柴彤拖央镶茵匝崇尺橙孪捅活授前置胎盘教案一、教学目标及基本要求 了解病因及分类。 熟悉临床表现及诊断方法。 掌握处理方法和原则。二、教学内容提要及时间分配 1. 病因分类（完全性、部分性、低置性），对母儿的影响。（5min） 2. 临床表现、诊断、根据病史、查体及辅助检查措施。(20min) 3. 处理方法，期待疗法和终止妊娠。（12min） 4. 预防的方法。(5min) 5. 新进展。(3min)三、教学重点及难点 重点：前置胎盘的临床表现、分类、诊断与鉴别诊断，处理原则。 难点：前置胎盘的鉴别诊断和处理。四、教学方法 病例式、问题式、讨论式 一般了解的内容同学自学。五、教学手段（挂图、幻灯、多媒体等） 利用CAI进行讲解，双语教学六、使用的教材及参考资料 1. 使用的教材：妇产科学（第六版） 2. 参考资料：（1）中华妇产科学 （2）Willianms obstetraics （第21版）七、授课教师：腊晓琳讲师八、授课对象：临床医学本科班、本硕班。前 置 胎 盘（Placenta Previa） 胎盘在正常情况下附着于子宫体部的后壁、前壁或侧壁。孕28周后若胎盘附着于子宫下段，甚至胎盘下缘达到或覆盖宫颈内口，其位置低于胎先露部，称前置胎盘。Placenta previa is generally defined as the implantation of the placenta over or near the internal os of the cervix after 28 Gestational weeks.前置胎盘是妊娠晚期出血的主要原因之一，是妊娠期的严重并发症，处理不当能危及母儿生命。其发生率20世纪60-80年代为0.22-0.27,1992年报道为0.24-1.57。病因 可能与下列因素有关:子宫内膜病变与损伤 胎盘面积过大 胎盘异常 受精卵滋养层发育迟缓分类 以胎盘边缘与宫颈内口的关系，将前置胎盘分为3种类型。边缘性前置胎盘Marginal placenta previa - the placenta is at the margin of the internal os部分性前置胎盘Partial placenta previa - the placenta is partially over the cervix.完全性前置胎盘(中央性前置胎盘) Total placenta previa:the placenta completely covers the cervix.临床表现妊娠晚期或临产时发生无诱因无痛性反复阴道流血是前置胎盘的主要症状。Painless hemorrhage is the cardinal sign of placenta previa. 1 症状 阴道流血发生时间早晚、反复发生次数、出血量多少与前置胎盘类型关系密切。由于反复多次或大量阴道流血，患者出现贫血，贫血程度与出血量成正比，出血严重者可发生休克，还能导致胎儿缺氧、窘迫，甚至死亡。出血是由于妊娠晚期或临产后子宫下段逐渐伸展，位于宫颈内口的胎盘不能相应地伸展，导致前置部分的胎盘自其附着处剥离，使血窦破裂而出血。患者一般状况随出血量而定，大量出血呈现面色苍白、脉搏微弱、血压下降等休克征象。 2体征 因子宫下段有胎盘占据，影响胎先露部入盆，故先露部高浮，约有15%并发胎位异常，尤其为臀先露。腹部检查见子宫大小与停经周数相符 ， 临产时检查宫缩为阵发性，间歇期子宫完全放松。有时可在耻骨联合上方听到胎盘杂音。诊断 1病史 2体征 3阴道检查 仅适用于终止妊娠前为明确诊断并决定分娩方式。 必须在有输液、输血及手术的条件下方可进行。若诊断已明确或流血过多不应再作阴道检查。检查方法：严格消毒外阴后用阴道窥器检查，观察有无阴道壁静脉曲张、宫颈息肉、宫颈癌等。窥诊后用一手食、中两指在宫颈周围的阴道弯隆部轻轻触诊，若扪及胎先露部可以排除前置胎盘，若发现手指与胎先露部之间有较厚软组织(胎盘)，应考虑为前置胎盘。若宫口已部分扩张，无活动性出血，可将食指轻轻伸入宫颈，检查有无海绵样组织(胎盘)，若为血块触之易碎。注意胎盘边缘与宫口的关系，以确定前置胎盘类型。若触及胎膜并决定破膜者，则行人工刺破胎膜。操作应轻柔，避免胎盘组织从附着处进一步分离引起大出血。若检查时发生大出血，应立即停止阴道检查，改行剖宫产术结束分娩，或急速破膜诱发宫缩以胎头压迫胎盘而暂时止血。 4超声检查 B型超声断层显像可清楚看到子宫壁、胎先露部、胎盘和宫颈的位置，并根据胎盘边缘与宫颈内口的关系进一步明确前置胎盘类型。胎盘定位准确率高达95%以上。B型超声诊断前置胎盘时须注意妊娠周数。妊娠中期胎盘占据宫壁一半面积，因此胎盘贴近或覆盖宫颈内口的机会较多;妊娠晚期胎盘占据宫壁面积减少到1/3或1/4。子宫下段形成及伸展增加了宫颈内口与胎盘边缘之间的距离，故原似在子宫下段的胎盘可随宫体上移而改变成正常位置胎盘。所以许多学者认为，若妊娠中期B型超声检查发现胎盘前置者，不宜诊断为前置胎盘，而应称胎盘前置状态。近年有报道用阴道B型超声检查，能清楚辨认宫颈内口与胎盘的关系，其准确率几乎达100%，能减少腹部B型超声检查存在的假阳性率或假阴性率。操作时应轻柔，避免出血，并预防感染。 5产后检查胎盘及胎膜 对产前出血患者，于产后应仔细检查娩出的胎盘，以便核实诊断。前置部位的胎盘有黑紫色陈旧血块附着。若胎膜破口距胎盘边缘距离7cm则为前置胎盘。若行剖宫产，术中能直接了解胎盘位置，胎膜破口失去诊断意义。 综上所述，多数学者认为，在孕28周后，经B型超声、阴道检查、剖宫产或经阴道产后确定胎盘附着部位异常者，方可诊断为前置胎盘。孕28周前属流产范畴，通常不诊断前置胎盘，但在孕中期引产者，要注意胎盘位置不正常的问题。鉴别诊断 妊娠晚期出血主要应与胎盘早剥相鉴别。其它原因发生的产前出血，有脐带帆状附着的前置血管破裂、胎盘边缘血窦破裂、宫颈息肉、宫颈糜烂、宫颈癌等，结合病史通过阴道检查、B型超声检查及分娩后胎盘检查可以确诊。羊水栓塞早产及围生儿死亡率高对母儿影响植入性胎盘产褥感染产后出血预防 搞好计划生育，推广避孕，防止多产，避免多次刮宫、引产或宫内感染，减少子宫内膜损伤或子宫内膜炎。加强孕妇管理及宣教。对妊娠期出血，无论量多少均须就医，做到及时诊断，正确处理。处理 处理原则应是止血补血。根据阴道流血量、有无休克、妊娠周数、产次、胎位、胎儿是否存活，是否临产等做出决定。 1期待疗法：期待疗法的目的是在保证孕妇安全的前提下保胎。 减少母亲出血、促进胎儿存活、适时进行分娩三个方面。大量资料显示不论前置胎盘何种类型，平均临产时间在35周左右，因此时生理性子宫收缩频度增多，故出血频率增加，所以期待至孕36周最合适，资料表明36周主动终止妊娠比等待至36周以上自然发动分娩围生儿死亡率低。 2终止妊娠(1)终止妊娠指征：反复多量出血致贫血甚至休克，无论胎儿成熟与否，为了母亲安全而终止妊娠；胎龄达36周以后；胎儿成熟度检查提示胎儿肺成熟者。 (2)剖宫产术：剖宫产能迅速结束分娩，达到止血目的，使母儿相对安全，是目前处理前置胎盘的主要手段。完全性和部分性前置胎盘的处理，约7090采用剖宫产。剖宫产中半数以上出血超过500m1，因出血行子宫切除达4-5。因此前置胎盘行剖宫产时须注意：做好防止和抢救出血的一切准备术前做B型超声检查行胎盘定位以利选择应变措施积极纠正贫血，预防感染等根据前置胎盘类型与附着部位选择子宫切口非常重要胎儿娩出后立即子宫肌壁内注射宫缩剂，胎盘附着面的血窦的止血方法。可行子宫动脉、髂内动脉结扎术或子宫全切除术或低位子宫次全切除术 (3)阴道分娩：仅适用于边缘性前置胎盘、枕先露、流血不多、估计在短时间内能结束分娩者。决定阴道分娩后，先行人工破膜，破膜后胎头下降压迫胎盘止血，并可促进子宫收缩加速分娩，若破膜后胎先露部下降不理想，仍有出血，或分娩进展不顺利，应立即改行剖宫产术。 (4)紧急转送的处理:患者阴道大量流血而当地无条件处理，先输液输血，在消毒下进行阴道填纱、腹部加压包扎，以暂时压迫止血，并迅速护送转院治疗。 小结：孕28周后若胎盘附着于子宫下段，甚至胎盘下缘达到或覆盖宫颈内口，其位置低于胎先露部，称前置胎盘。前置胎盘是妊娠晚期出血的主要原因之一，是妊娠期的严重并发症，处理不当能危及母儿生命。以胎盘边缘与宫颈内口的关系，将前置胎盘分为3种类型：完全性前置胎盘、部分性前置胎盘和边缘性前置胎盘。妊娠晚期或临产时，发生无诱因无痛性反复阴道流血是前置胎盘的主要症状。临床处理需根据阴道流血量、有无休克、妊娠周数、产次、胎位、胎儿是否存活，是否临产等做出决定。处理方法有期待疗法和终止妊娠。思考题：1 前置胎盘如何分类？有何临床特点和体征？2 试述前置胎盘的处理原则。3 What is the mainly symptom of Placenta Previa?A. Sudden vaginal bleeding with badly abdominal painB. Hypovolemic shock present without too much vaginal bleeding.C. Painless hemorrhage is the cardinal sign.D. The first episode of hemorrhage usually begins in labor.429岁初孕妇，妊娠32周，3周内阴道流血两次多于月经量，不伴腹痛，血压13.3/10.7Kpa,脉搏96次/分，宫高30厘米，腹围85厘米，近宫底部可触到软而不规则的胎儿部分，胎心清楚144次/分。（1）应考虑的诊断是什么？（2）首选的辅助检查是什么？（3）该患合适的治疗原则是什么？Reference PaperVaginal bleeding in later pregnancy and labourPROBLEMS Vaginal bleeding after 22 weeks of pregnancy. Vaginal bleeding in labour before delivery. Types of bleeding Type of BleedingProbable DiagnosisActionBlood-stained mucus (show)Onset of labourProceed with management of normal labour and childbirthAny other bleedingAntepartum haemorrhageDetermine cause (Table S-6)GENERAL MANAGEMENT SHOUT FOR HELP. Urgently mobilize all available personnel. Make a rapid evaluation of the general condition of the woman including vital signs (pulse, blood pressure, respiration, temperature). Do not do a vaginal examination at this stage. If shock is suspected, immediately begin treatment. Even if signs of shock are not present, keep shock in mind as you evaluate the woman further because her status may worsen rapidly. If shock develops, it is important to begin treatment immediately.Start an IV infusion and infuse IV fluids. DIAGNOSIS Diagnosis of antepartum haemorrhagePresenting Symptom and Other Symptoms and Signs Typically PresentSymptoms and Signs Sometimes Present Probable Diagnosis Bleeding after 22 weeks gestation (may be retained in the uterus) Intermittent or constant abdominal pain Shock Tense/tender uterus Decreased/absent fetal movements Fetal distress or absent fetal heart soundsAbruptio placentae Bleeding (intra-abdominal and/or vaginal) Severe abdominal pain (may decrease after rupture) Shock Abdominal distension/ free fluid Abnormal uterine contour Tender abdomen Easily palpable fetal parts Absent fetal movements and fetal heart sounds Rapid maternal pulseRuptured uterus Bleeding after 22 weeks gestation Shock Bleeding may be precipitated by intercourse Relaxed uterus Fetal presentation not in pelvis/lower uterine pole feels empty Normal fetal conditionPlacenta praeviaMANAGEMENT ABRUPTIO PLACENTAE Abruptio placentae is the detachment of a normally located placenta from the uterus before the fetus is delivered. Assess clotting status using a bedside clotting test. Failure of a clot to form after 7 minutes or a soft clot that breaks down easily suggests coagulopathy. Transfuse as necessary, preferably with fresh blood. If bleeding is heavy (evident or hidden), deliver as soon as possible: - If the cervix is fully dilated, deliver by vacuum extraction; - If vaginal delivery is not imminent, deliver by caesarean section. Note: In every case of abruptio placentae, be prepared for postpartum haemorrhage. If bleeding is light to moderate (the mother is not in immediate danger), the course of action depends on the fetal heart sounds: - If fetal heart rate is normal or absent, rupture the membranes with an amniotic hook or a Kocher clamp: - If contractions are poor, augment labour with oxytocin; - If the cervix is unfavourable (firm, thick, closed), perform caesarean section. - If fetal heart rate is abnormal (less than 100 or more than 180 beats per minute): - Perform rapid vaginal delivery; - If vaginal delivery is not possible, deliver by immediate caesarean section. COAGULOPATHY (CLOTTING FAILURE) Coagulopathy is both a cause and a result of massive obstetric haemorrhage. It can be triggered by abruptio placentae, fetal death in-utero, eclampsia, amniotic fluid embolism and many other causes. The clinical picture ranges from major haemorrhage, with or without thrombotic complications, to a clinically stable state that can be detected only by laboratory testing. Note: In many cases of acute blood loss, the development of coagulopathy can be prevented if blood volume is restored promptly by infusion of IV fluids (normal saline or Ringers lactate). Treat the possible cause of coagulation failure: - abruptio placentae; - eclampsia. Use blood products to help control haemorrhage: - Give fresh whole blood, if available, to replace clotting factors and red cells; - If fresh whole blood is not available, choose one of the following based on availability: - fresh frozen plasma for replacement of clotting factors (15 mL/kg body weight); - packed (or sedimented) red cells for red cell replacement; - cryoprecipitate to replace fibrinogen; - platelet concentrates (if bleeding continues and the platelet count is less than 20 000). RUPTURED UTERUS Bleeding from a ruptured uterus may occur vaginally unless the fetal head blocks the pelvis. Bleeding may also occur intra-abdominally. Rupture of the lower uterine segment into thebroad ligament, however, will not release blood into the abdominal cavity (Fig S-2). Figure S-2 Rupture of lower uterine segment into broad ligament will not release blood into the abdominal cavity Restore blood volume by infusing IV fluids (normal saline or Ringers lactate) before surgery. When stable, immediately perform caesarean section and deliver baby and placenta. If the uterus can be repaired with less operative risk than hysterectomy would entail and the edges of the tear are not necrotic, repair the uterus. This involves less time and blood loss than hysterectomy. Because there is an increased risk of rupture with subsequent pregnancies, the option of permanent contraception needs to be discussed with the woman after the emergency is over. If the uterus cannot be repaired, perform subtotal hysterectomy. If the tear extends through the cervix and vagina, total hysterectomy may be required. PLACENTA PRAEVIA Placenta praevia is implantation of the placenta at or near the cervix (Fig S-3). Figure S-3 Implantation of the placenta at or near the cervix. Warning: Do not perform a vaginal examination unless preparations have been made for immediate caesarean section. A careful speculum examination may be performed to rule out other causes of bleeding such as cervicitis, trauma, cervical polyps or cervical malignancy. The presence of these, however, does not rule out placenta praevia. Restore blood volume by infusing IV fluids (normal saline or Ringers lactate). Assess the amount of bleeding: - If bleeding is heavy and continuous, arrange for caesarean delivery irrespective of fetal maturity; - If bleeding is light or if it has stopped and the fetus is alive but premature, consider expectant management until delivery or heavy bleeding occurs: - Keep the woman in the hospital until delivery; - Correct anaemia with ferrous sulfate or ferrous fumerate 60 mg by mouth daily for 6 months; - Ensure that blood is available for transfusion, if required; - If bleeding recurs, decide management after weighing benefits and risks for the woman and fetus of further expectant management versus delivery. CONFIRMING THE DIAGNOSIS If a reliable ultrasound examination can be performed, localize the placenta. If placenta praevia is confirmed and the fetus is mature, plan delivery. If ultrasound is not available or the report is unreliable and the pregnancy is less than 37 weeks, manage as placenta praevia until 37 weeks. If ultrasound is not available or the report is unreliable and the pregnancy is 37 weeks or more, examine under double set-up to exclude placenta praevia. The double set-up prepares for either vaginal or caesarean delivery, as follows: - IV lines are running and cross-matched blood is available; - The woman is in the operating theatre with the surgical team present; - A high-level disinfected vaginal speculum is used to see the cervix. If the cervix is partly dilated and placental tissue is visible, confirm placenta praevia and plan delivery. If the cervix is not dilated, cautiously palpate the vaginal fornices: - If spongy tissue is felt, confirm placenta praevia and plan delivery; - If a firm fetal head is felt, rule out major placenta praevia and proceed to deliver by induction. If a diagnosis of placenta praevia is still in doubt, perform a cautious digital examination: - If soft tissue is felt within the cervix, confirm placenta praevia and plan delivery (below); - If membranes and fetal parts are felt both centrally and marginally, rule out placenta praevia and proceed to deliver by induction. DELIVERY Plan delivery if: - the fetus is mature; - the fetus is dead or has an anomaly not compatible with life (e.g. anencephaly); - the womans life is at risk because of excessive blood loss. If there is low placental implantation (Fig S-3 A) and bleeding is light