Hypertensive disorders in pregnancy

1

• Hypertensive disorders in pregnancy
• Lectures 4

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Hypertension in PregnancySignificance and
incidence

• Hypertensive disorders of pregnancy are the most
  common medical complication reported during
  pregnancy
• Preeclampsia complicates approximately 5 to 10
  of all pregnancies
• Significant contributor to maternal and perinatal
  morbidity and mortality In woman with history of
  chronic hypertension or renal disease predating
  pregnancy the occurrence of preeclampsia is 25

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Hypertension in Pregnancy Significance and
incidence

• Preeclampsia predisposes the woman to potentially
  lethal complications, including eclampsia,
  abruptio placentae, disseminal intravascular
  coagulation, acute renal failure, adult
  respiratory distress syndrome, cerebral
  hemorrhage
• Causes of perinatal death related to preeclampsia
  are uteroplacental insufficiency and abruptio
  placentae, which lead to intrauterine fetal
  death, preterm birth, and low birth weight

4
Hypertension in PregnancySignificance and
incidence

• Eclampsia (characterized by seizures) from
  profound cerebral effects of preeclampsia is the
  major maternal hazard.
• As a rule, maternal and perinatal morbidity and
  mortality rates are highest among cases in which
  eclampsia is seen early in gestation (before 28
  weeks), maternal age is greater than 25 years,
  the woman is a multigravida, and chronic
  hypertension or renal disease is present
• The fetus of the eclamptic woman is at increased
  risk from abruptio placentae, preterm birth,
  intrauterine growth restriction (IUGR), and acute
  hypoxia

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Hypertension in Pregnancy Classification

• Chronic hypertension
• Pregnancy-induced hypertension
• Gestational hypertension
• Preeclampsia
• Eclampsia
• Preeclampsia superimposed on chronic hypertension
• Standard definitions are not consistently used by
  health care providers

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Chronic hypertension

• Present before the pregnancy or diagnosed before
  week 20 of gestation
• or continuing beyond 42 days postpartum

7
Gestational hypertension

• Onset of hypertension without proteinuria after
  the 20th week of pregnancy
• Systolic BP gt 140 mm Hg
• Diastolic BP gt90 mm Hg
• Diagnosis of onset during pregnancy based on two
  measurements that meet criteria for gestational
  BP elevation within a 1-week period

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Preeclampsia

• Pregnancy-specific syndrome
• Hypertension develops after 20 weeks of gestation
  in previously normotensive woman
• Proteinuria may be present
• Multisystem, vasospastic disease process
  characterized by hemoconcentration, hypertension,
  and proteinuria
• Disease of reduced organ perfusion with presence
  of hypertension and proteinuria
• Complicates 3 to 7 of all pregnancies

9
Proteinuria

• is a concentration of 0.1 g/L (1 to 2 on
  dipstick measurement) or more in at least two
  random urine specimens collected at least 6 hours
  apart.
• In a 24-hour specimen, proteinuria is a
  concentration of 0.3 g/L per 24 hours

10
Edema

• Pathologic edema is clinically evident,
  generalized accumulation of fluid of the face,
  hands, or abdomen that is not responsive to 12
  hours of bed rest. It may also be manifested as a
  rapid weight gain of more than 2 kg in 1 week.
  The presence of edema is no longer considered
  necessary for the diagnosis of preeclampsia

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Preeclampsia
MILD PREECLAMPSIA SEVERE PREECLAMPSIA SEVERE PREECLAMPSIA
MATERNAL EFFECTS MATERNAL EFFECTS MATERNAL EFFECTS MATERNAL EFFECTS
Blood pressure BP reading of 140/90 mm Hg x2, 4-6 hr apart BP reading of 140/90 mm Hg x2, 4-6 hr apart Rise to gt160/110 mm Hg on two separate occasions 4-6 hr apart with pregnant woman on bed rest
Mean arterial pressure (MAP) gt105 mm Hg gt105 mm Hg gt105 mm Hg
Weight gain Weight gain of more than 0.5 kg/wk during the second and third trimesters or sudden weight gain of 2 kg/wk at any time Weight gain of more than 0.5 kg/wk during the second and third trimesters or sudden weight gain of 2 kg/wk at any time Same as mild preeclampsia
Proteinuria Qualitative dipstick Ouantitative 24 hr analysis Proteinuria of 0.3 g/L in a 24 hr specimen or gt0.1 g/L in a random day-time specimen on two or more occasions 6 hr apart (because protein loss is variable) with dipstick, values varying from 1 to 2 Proteinuria of 0.3 g/L in a 24 hr specimen or gt0.1 g/L in a random day-time specimen on two or more occasions 6 hr apart (because protein loss is variable) with dipstick, values varying from 1 to 2 Proteinuria of gt0.5 g/L in 24 hr or gt4 protein on dipstick
Edema Dependent edema, some puffiness of eyes, face, fingers pulmonary edema absent Dependent edema, some puffiness of eyes, face, fingers pulmonary edema absent Generalized edema, noticeable puffiness eyes, face, fingers pulmonary edema possibly present
Reflexes May be normal May be normal Hyperreflexia 3, possible ankle clonus
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Preeclampsia
MILD PREECLAMPSIA SEVERE PREECLAMPSIA SEVERE PREECLAMPSIA
MATERNAL EFFECTS MATERNAL EFFECTS MATERNAL EFFECTS MATERNAL EFFECTS
Reflexes May be normal May be normal Hyperreflexia 3, possible ankle clonus
Urine output Output matching intake, 30 ml/hr or lt650 ml/24 hr Output matching intake, 30 ml/hr or lt650 ml/24 hr lt20 ml/hr or lt400 ml to 500 ml/24 hr
Headache Absent/transient Absent/transient Severe
Visual problems Absent Absent Blurred, photophobia, blind spots on funduscopy
Irritability/changes in affect Transient Transient Severe
Epigastric pain Absent Absent Present
Serum creatinine Normal Normal Elevated
Thrombocytopenia Absent Absent Present
AST elevation Normal or minimal Normal or minimal Marked
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Preeclampsia
MILD PREECLAMPSIA SEVERE PREECLAMPSIA SEVERE PREECLAMPSIA
FETAL EFFECTS FETAL EFFECTS FETAL EFFECTS FETAL EFFECTS
Placental perfusion Reduced Reduced Decreased perfusion expressing as IUGR in fetus FHR late decelerations
Premature placental aging Not apparent Not apparent At birth placenta appearing smaller than normal for duration of pregnancy, premature aging apparent with numerous areas of broken syncytia, ischemic necroses (white infarcts) numerous, intervillous fibrin deposition (red infarcts)
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HELLP syndrome

• is a laboratory diagnosis for a variant of severe
  preeclampsia characterized by hemolysis (H),
  elevated liver enzymes (EL), and low platelets
  (LP)

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Eclampsia

• Seizure activity or coma in woman diagnosed with
  preeclampsia
• No history of previous seizure disorder
• Presentation varies
• One third in labor
• One third during delivery
• One third within 72 hours postpartum

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Chronic hypertension with superimposed
preeclampsia

• Women with chronic hypertension may acquire
  preeclampsia or eclampsia
• Increases morbidity for mother and fetus

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Etiology

• Unique to human pregnancies
• Signs and symptoms develop only during pregnancy
  and disappear after birth of the fetus and
  passage of placenta
• The cause is unknown
• Associated high risk factors
• Primigravidity
• Multifetal pregnancy
• Preexisting medical condition (Obesity, Chronic
  renal disease, Chronic hypertension, Diabetes)
• Preeclampsia in a prior pregnancy or Family
  history of PIH
• Maternal age lt19 years gt40 years
• Rh incompatibility

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Etiology

• Current theories
• Increase vasoconstrictor tone
• Abnormal prostaglandin action
• Endotelian cell activation
• Immunologic factor
• Genetic disposition
• diet

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Pathophysiology

• May be caused by disruptions in placental
  perfusion and endothelial cell dysfunction
• Main pathogenic factor is not an increase in BP,
  but poor perfusion resulting from vasospasm
• Arteriolar vasospasm diminishes diameter of blood
  vessels, which impedes blood flow to all organs
  and increases BP
• Significant decreases in placental, kidney,
  liver, and brain function

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Pathophysiology

• reflects alterations in the normal adaptations of
  pregnancy.
• Normal physiologic adaptations to pregnancy
  include increased blood plasma volume,
  vasodilatation, decreased systemic vascular
  resistance, elevated cardiac output, and
  decreased colloid osmotic pressure
• Pathologic changes in the endothelial cells of
  the glomeruli (glomeruloendotheliosis) are
  uniquely characteristic of preeclampsia,
  particularly in nulliparous women (85).
• The main pathogenic factor is not an increase in
  blood pressure but poor perfusion as a result of
  vasospasm. Arteriolar vasospasm diminishes the
  diameter of blood vessels, which impedes blood
  flow to all organs and raises blood pressure
• Function in organs such as the placenta,
  kidneys, liver, and brain is depressed by as much
  as 40 to 60

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HELLP syndrome

• Laboratory diagnostic variant (not clinical)
  variant of severe preeclampsia involves hepatic
  dysfunction, characterized by
• Hemolysis (H)
• Elevated liver enzymes (EL)
• Low platelets (LP)

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HELLP syndrome

• The exact mechanism is unknown
• Arteriolar vasospasm, endothelial damage, and
  platelet aggregation with resultant tissue
  hypoxia are the underlying mechanisms for the
  pathophysiology of HELLP syndrome

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HELLP syndrome

• epigastric or right upper quadrant abdominal pain
  (possibly related to hepatic ischemia) 65
• nausea and vomiting 50

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HELLP syndrome

• Lab test
• platelet count less than 100,000/mm3
• Elevate liver enzymes levels
• aspartate aminotransferase AST
• alanine aminotransferase ALT)
• evidence of intravascular hemolysis (burr cells
  on peripheral smear or elevated bilirubin level)
• A unique form of coagulopathy (not DIC) occurs
  with HELLP syndrome. The platelet count is low,
  but coagulation factor assays,
• prothrombin time
• partial thromboplastin time
• bleeding time remain normal

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HELLP syndrome

• Associated with increased risk for
• Pulmonary edema
• Acute renal failure
• Disseminated intravascular coagulation (DIC)
• Placental abruption
• Liver hemorrhage or failure
• Adult respiratory distress syndrome
• Sepsis
• Stroke
• High risk for maternal death

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Care management
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Chronic Hypertension

• Chronic hypertension associated with increased
  incidence of
• Abruptio placentae
• Superimposed preeclampsia
• Increased perinatal mortality
• Fetal effects
• Fetal growth restriction
• Small for gestational age

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Chronic Hypertension contd

• Ideally management begins before conception
• Lifestyle changes may be necessary
• In postpartum, high risk women monitored closely
  for complications
• May safely breastfeed even though low levels of
  antihypertensive medications will be in breast
  milk

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Assessment and nursing diagnosis

• Interview
• Medical history
• DM, renal disease, chronic hypertension
• Family history
• Social history (marital, nutritional status,
  cultural beliefs, activity level, health habits)
• BP
• Abnormal weight gain
• Increase sign of edema
• Presents of proteinuria
• Headache
• Visual disturbance
• Epigastric pain

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Assessment and nursing diagnosis

• Physical examination
• BP
• Observation of edema (distribution, degree,
  pitting)
• Symptom reflecting central nervous system and
  visual system
• Deep tendon reflexes
• Fetal status
• Uterine tonicity
• Sign of progression of mild preeclampsia to
  severe preeclampsia or eclampsia
• Respiration (crackles, diminished breath sound)

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Assessment and nursing diagnosis

• Lab tests
• Complete blood cell count (including a platelet
  count), hematocrit, hemoglobin
• Clotting studies (including bleeding time, PT
  (protrombine time), PTT (partial thromboplastin
  time), and fibrinogen)
• Liver enzymes (lactate dehydrogenase
  LDH, AST, ALT), glucose level
• Chemistry panel (blood urea nitrogen BUN,
  creatinine, glucose, uric acid),
• Type and screen, possible crossmatch
• Proteinuria

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Lab tests
NORMAL PIH HELLP
Hemoglobin/hematocrit 12 to 16 gm/dl/37 to 47 May ? ?
Platelets 150,000 to 400,000/mm3 Unchanged lt100,000/mm3
PT/PTT 12 to 14 sec/60 to 70 sec Unchanged Unchanged
Fibrinogen 150 to 400 mg/dl 300 to 600 mg/dl Present
Fibrin split products (FSP) Absent Absent ?
Blood urea nitrogen (BUN) 10 to 20 mg/dl lt10 mg/dl ?
Creatinine 0.5 to 1.1 mg/dl lt1 mg/dl ?
Lactate dehydrogenase (LDH) 45 to 90 U/L Unchanged ?
Aspartate aminotransferase (AST) 4 to 20 U/L Unchanged ?
Alanine aminotransferase (ALT) 3 to 21 U/L Unchanged ?
Creatinine clearance 80 to 125 ml/min 130 to 180 ml/min ?
Burr cells/schistocytes Absent Absent Present
Uric acid 2 to 6.6 mg/dl 4.5 to 6 mg/dl gt10 mg/dl
Bilirubin (total) 0.1 to 1 mg/dl Unchanged or ? ?
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Preeclampsia

• Nursing actions are derived from medical
  management, health care provider directives, and
  nursing diagnoses.
• Early prenatal care, identification of pregnant
  women at risk for preeclampsia, and recognition
  and reporting of physical warning signs are
  essential components in the optimization of
  maternal and perinatal outcomes.
• The role of the nurse's skills in assessing the
  woman for factors and symptoms of preeclampsia
  cannot be overestimated

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Mild preeclampsia

• Goal is to ensure maternal safety and deliver a
  healthy newborn
• May be safely managed at home by nurse (2-3 times
  per week) or by themself
• Maternal assessment (weight, urine dipstick
  protein determination, BP, DFMC)
• Fetal assessment (ultrasound every 3 weeks, DFMC,
  NST or BPP 1-2 times per week
• Activity restriction
• Diet

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Severe preeclampsia and HELLP-syndrome

• At greater risk for pregnancy complications
• Should be hospitalized for at least 24 hours for
  observation and treatment if necessary
• Intrapartum care
• Magnesium sulfate
• Control of blood pressure
• Postpartum care

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Severe preeclampsia and HELLP-syndrome

• Antepartum care
• focuses on stabilization and preparation for
  birth.
• Assessments include review of the cardiovascular
  system, pulmonary system, renal system,
  hematologic system, and CNS.
• Fetal assessments for well-being (e.g., NST, BPP,
  Doppler velocimetry) are important because of the
  potential for hypoxia related to uteroplacental
  insufficiency.
• Baseline laboratory assessments include metabolic
  studies for liver enzyme (AST, ALT, LDH)
  determination, complete blood count with
  platelets, coagulation profile to assess for DIC,
  and electrolyte studies to establish renal
  functioning.
• Weight is measured on admission and every day
  thereafter.

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Severe preeclampsia and HELLP-syndrome

• An indwelling urinary catheter facilitates
  monitoring of renal function and effectiveness of
  therapy.
• If appropriate, vaginal examination may be done
  to check for cervical changes.
• Abdominal palpation establishes uterine tonicity
  and fetal size, activity, and position.
• Electronic monitoring to determine fetal status
  is initiated at least once a day.
• The woman's room must be close to staff and
  emergency drugs, supplies, and equipment. Noise
  and external stimuli must be minimized. Seizure
  precautions are taken
• Bed rest is commonly ordered.

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Severe preeclampsia and HELLP-syndrome

• Intrapartum nursing care
• involves continuous monitoring of maternal and
  fetal status as labor progresses. The assessment
  and prevention of tissue hypoxia and hemorrhage,
  both of which can lead to permanent compromise of
  vital organs, continue throughout the intrapartum
  and postpartum periods (Leicht Harvey, 1999).

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Severe preeclampsia and HELLP-syndromeMagnesium
sulfate

• As prophylaxis against convulsion
• I/V as a secondary infusion to the main
  intravenous (IV) line by volumetric infusion pump
  
• An initial loading dose of 4 to 6 g of MgSO4 per
  protocol or physician's order is infused over 20
  to 30 minutes. This dose is followed by a
  maintenance dose of magnesium sulfate that is
  diluted in an IV solution per physician's order
  (e.g., 40 g of magnesium sulfate in 1000 ml of
  lactated Ringer's solution) and administered by
  infusion pump at 1 to 3 g/hr.
• This dose should maintain a therapeutic serum Mg
  level of 4 to 8 g/dl.
• Serum magnesium levels are obtained after the
  patient has received magnesium sulfate for 4 to 6
  hours.

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Severe preeclampsia and HELLP-syndrome Magnesium
sulfate

• Intramuscular (IM) MgSO4 is seldom used because
  absorption rate cannot be controlled, injections
  are painful, and tissue necrosis may occur.
• However, the IM route may be used with some women
  who are being transported to a tertiary care
  center.
• The IM dose is 4 to 5 g given in each buttock, a
  total of 10 g (with 1 procaine possibly being
  added to the solution to reduce injection pain),
  and can be repeated at 4-hour intervals.
• Z-track technique should be used for the deep IM
  injection, followed by gentle massage at the site.

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Severe preeclampsia and HELLP-syndrome Magnesium
sulfate

• Magnesium sulfate interferes with the release of
  acetylcholine at the synapses,
• decreasing neuromuscular irritability,
• depressing cardiac conduction,
• and decreasing CNS (central nervous system)
  irritability.
• Because magnesium circulates free and unbound to
  protein and is excreted in the urine, accurate
  recordings of maternal urine output must be
  obtained.
• Diuresis is an excellent prognostic sign
  however, if renal function declines, all of the
  magnesium sulfate will not be excreted and can
  cause magnesium toxicity.
• Serum magnesium levels are obtained on the basis
  of the woman's response and if any signs of
  toxicity are present.
• Early symptoms of toxicity include nausea, a
  feeling of warmth, flushing, muscle weakness,
  decreased reflexes, and slurred speech.

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Severe preeclampsia and HELLP-syndrome Magnesium
sulfate

• Deep tendon reflexes
• Urine output
• Respiration rate
• Consciousness
• If magnesium toxicity is suspected, the infusion
  should be discontinued immediately.
• Calcium gluconate, the antidote for magnesium
  sulfate, may also be ordered (10 ml of a 10
  solution, or 1 g) and given by slow IV push
  (usually by the physician) over at least 3
  minutes to avoid undesirable reactions such as
  arrhythmias, bradycardia, and ventricular
  fibrillation.
• Because magnesium sulfate is also a tocolytic
  agent, its use may increase the duration of
  labor. A preeclamptic woman receiving magnesium
  sulfate may need augmentation with oxytocin
  during labor. The amount of oxytocin needed to
  stimulate labor may be more than that needed for
  a woman who is not on magnesium sulfate.

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Severe preeclampsia and HELLP-syndrome
antihypertensive agent

• Starts if diastolic pressure is higher than 100
  to 110 mm Hg
• Order to decrease the diastolic blood pressure to
  90 to 100 mm Hg
• Prevent left ventricular failure and cerebral
  hemorrhage.
• decrease the arterial pressure too much or too
  rapidly
• agent of choice is
• hydralazine IV
• labetalol hydrochloride IV
• methyldopa orally
• Nifedipine orally

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Eclampsia

• Premonitory signs and symptoms
• Headache
• Blurred vision
• Severe epigastric pain
• Altered mental status
• Tonic- clonic convulsions
• Hypotension
• Coma

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Eclampsia

• Immediate care
• Ensure a patent airway
• Patient safety a major concern
• Post-seizure decision regarding timing and method
  of birth

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EclampsiaTONIC-CLONIC CONVULSION SIGNS

• Stage of invasion 2 to 3 sec, eyes are fixed,
  twitching of facial muscles occurs
• Stage of contraction 15 to 20 sec, eyes protrude
  and are bloodshot, all body muscles are in tonic
  contraction
• Stage of convulsion muscles relax and contract
  alternately (clonic), respirations are halted and
  then begin again with long, deep, stertorous
  inhalation, coma ensues

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EclampsiaINTERVENTION

• Keep airway patent turn head to one side, place
  pillow under one shoulder or back if possible
  Call for assistance Protect with side rails up
  Observe and record convulsion activity

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Eclampsia AFTER CONVULSION OR SEIZURE

• Do not leave unattended until fully alert
• Observe for postconvulsion coma, incontinence
• Use suction as needed
• Administer oxygen via face mask at 10 L/min
• Start IV fluids and monitor for potential fluid
  overload
• Give magnesium sulfate or other anticonvulsant
  drug as ordered
• Insert indwelling urinary catheter
• Monitor blood pressure
• Monitor fetal and uterine status
• Expedite laboratory work as ordered to monitor
  kidney function, liver function, coagulation
  system, and drug levels
• Provide hygiene and a quiet environment
• Support and keep woman and family informed
• Be prepared for delivery when woman is in stable
  condition

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Postpartum nursing care

• After birth the symptoms of preeclampsia or
  eclampsia resolve quickly, usually within 48
  hours.
• The hematopoietic and hepatic complications of
  HELLP syndrome may persist longer.
• These patients often show an abrupt decrease in
  platelet count, with a concomitant increase in
  LDH and AST levels, after a trend toward
  normalization of values has begun. Generally the
  laboratory abnormalities seen with HELLP syndrome
  resolve in 72 to 96 hours.
• Blood pressure is measured at least every 4 hours
  for 48 hours or more frequently as the woman's
  condition warrants.
• Even if no convulsions occurred before the birth,
  they may occur within this period.
• MgSO4 infusion may be continued 12 to 24 hours
  after the birth.
• Assessments for effects and side effects continue
  until the medication is discontinued.

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Postpartum nursing care

• The woman is at risk for a boggy uterus and a
  large lochial flow as a result of the magnesium
  sulfate therapy. Uterine tone and lochial flow
  must be monitored closely.
• The preeclamptic woman is unable to tolerate
  excessive postpartum blood loss because of
  hemoconcentration. Oxytocin or prostaglandin
  products are used to control bleeding.
• Ergot products (e.g., Ergotrate, Methergine) are
  contraindicated because they can increase blood
  pressure.
• The woman is asked to report symptoms such as
  headaches and blurred vision.
• The nurse assesses affect, level of
  consciousness, blood pressure, pulse, and
  respiratory status before an analgesic is given
  for headache.
• Magnesium sulfate potentiates the action of
  narcotics, CNS depressants, and calcium-channel
  blockers these drugs must be administered with
  caution.
• The woman may need to continue an
  antihypertensive medication regimen if her
  diastolic blood pressure exceeds 100 mm Hg at
  discharge.