Cases analysis of rational use of medicine (45) Hypertension of Pregnancy

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Casesanalysisofrationaluseofmedicine(45)HypertensionofPregnancy

1.Patient'sconditions

Patient，19-year-old female,was pregnant for 25 weeks.She had headache,nausea and epigastric pain.Blood pressure was 162/108 mmHg,the repeated measure of BP after an interval of 6 hours was the same as the first time.She had no history of hypertension.

Urinary protein:+

Diagnosis:preeclampsia

2.Drugadministration

25% Magnesium Sulfate Inj 40 ml

5% Glucose Inj 500 ml/iv drip

Hydralazine HCl Tab 10 mg tid

3.Analysis

(1)Preeclampsia:Development of hypertension with albuminuria or edema between the 20th wk of pregnancy and end of the first week postpartum.Eclampsia:coma and/or convulsive seizures in the same time period,without other etiology.

Preeclampsia develops usually in primigravidas and women with preexisting hypertension or vascular disease.If untreated,preeclampsia characteristically smoulders for a variable length of time and suddenly progresses to eclampsia.Eclampsia develops in a few preeclamptic patients and is usually fatal if untreated.A major complication of preeclampsia is placental abruption.

(2)Any pregnant woman who develops a BP of 140/90 mmHg,edema,or albuminuria of ≥1+ or whose BP rises by 30 mmHg systolic or 15 mmHg diastolic must be considered to have preeclampsia.Patients with a BP of ≥160/110 mmHg,marked edema or albuminuria (≥3.0 g/24 h)are considered to have severe preeclampsia.

(3)The treatment of preeclampsia is aimed at preserving the life and health of the mother,the fetus usually also survives.

Therapy for preeclampsia consists of hospitalization with bed rest (left lateral position),control of BP,seizure prophylaxis when signs of impending eclampsia are present and timely delivery.The treatment prior to delivery is to lessen symptoms,and principal agent is magnesium sulfate.

(4)Magnesium Sulfate(MgSO4) has anticonvulsant properties when administered parenterally and is used to control seizures in eclampsia.But something important must be paid attention to before the use of MgSO4.

a.Patient has patellar tendon reflex.

b.Patient's respiration rate is more than 16/min.

c.Urinary output of patient is more than 25 ml/h or 600 ml/24 h.

d.Calcium gluconate 1 gm iv should be prepared as specific antidote for excess MgSO4.

In severe preeclampsia,MgSO4in 5% Glucose Inj.should be infused slowly and continuously with supplemental doses as necessary,then the hyperreflexia that usually accompanies this disorder diminishes,thereby decreasing the risk of convulsions,concomitant lowering of BP usually occurs.If BP does not respond to MgSO4therapy,an iv infusion of urapidil or hydralazine may be started.But BP should never be lowered to <130/80 mmHg,because excessive BP reduction may compromise uteroplacental blood flow and jeopardize the fetus.

Hydralazine,an antihypertensive,has been used for many years in the hypertensive pregnant woman.It has benefits of increasing renal and uteroplacental blood perfusion and cardiac output.But tachycardia,palpitations,headache etc occur now and then with the use of hydralazine,prolonged use of large doses is associated with an increased incidence of lupus erythematosus.

Orally administered calcium channel blockers such as Nifedipine Retard Tablets,can be used in preeclampsia because of their effectiveness and rapid onset of action.

ACEIs,ARBs and β-blockers are usually not recommended in preeclampsia because of harmful effects on fetus.

合理用药案例分析(45)妊娠高血压

1.患者简介

患者，女性，19岁，妊娠25周时，出现头痛，恶心，上腹部不适，血压162/108 mmHg,间隔6小时后再测血压，仍是162/108 mmHg。患者无高血压患病史。

尿蛋白检查：+

诊断：子痫前期(原名先兆子痫)

2.用药

25%硫酸镁注射液 40 ml

5%葡萄糖注射液 500 ml/静滴

盐酸肼屈嗪片 10 mg 3次/d

3.用药分析

(1)子痫前期：在妊娠第20周到产褥期第1周之间发生的高血压，伴蛋白尿或水肿。

子痫：该时期内无其他病因学引起昏迷及/或痉挛发作。

子痫前期通常发生于初孕妇及既往有高血压及血管疾病的妇女。若不加治疗，子痫前期一般持续一段时间后突然发展为子痫。子痫前期患者中少数会出现子痫，若不加治疗常可致死。子痫前期的主要并发症是胎盘早期剥离。

(2)凡孕妇血压≥140/90 mmHg，水肿或蛋白尿(+)以上，或收缩压上升30 mmHg，或舒张压上升15 mmHg者，均应考虑子痫前期的存在。患者血压≥160/110 mmHg，伴明显水肿或蛋白尿(≥3.0 g/24 h)要视为重度子痫前期。

(3)治疗目标是保护母亲的生命和健康，并尽量保住胎儿。治疗通常要收住院，卧床休息(左侧卧)，控制血压，当有子痫迹象时要预防控制其发作，并适时终止妊娠。终止妊娠前治疗缓解其症状，首选用药为硫酸镁。

(4)注射用硫酸镁抗惊厥，可用于抗子痫发作。但硫酸镁使用前有些问题必须提起注意。

a.患者应存在膝腱反射；

b.患者呼吸次数要大于16次/min；

c.患者尿量要多于25 ml/h或600 ml/24 h；

d.用药准备10%葡萄糖酸钙10 ml，作为硫酸镁过量的解毒剂。

重度子痫前期，硫酸镁的葡萄糖稀释液，应缓慢连续静脉输注，必要时调整剂量，给药后神经反射增强减轻，并减少出现痉挛的危险，血压也随之降低。如果应用硫酸镁后血压降低不明显，则可静脉滴注乌拉地尔或肼屈嗪。但血压不要低于130/80 mmHg，过度降压有损于子宫胎盘血液灌注及胎儿的安全。

作为一降压药，肼屈嗪用于妊娠高血压多年。其优点是增加肾脏及子宫胎盘血流及心脏排血量，但随其应用，可发生心动过速、心悸头痛等不良反应，长期大量应用有增加红斑狼疮发病风险。口服钙拮抗剂类，如硝苯地平控释片，因其效果确实，起效迅速，也可用于子痫前期降压治疗。

血管紧张素转换酶抑制剂，血管紧张素受体拮抗剂及β-受体阻滞剂因其对胎儿有不利影响，通常不用于子痫前期降压治疗。

杜金山 编写

叶咏年 审校