Hypertensive Disorders of Pregnancy Flashcards
Epidemiology of PreE
- Complicates 2-8% of pregnancies
- Contributes to 16% of maternal deaths (26% in Latin Amer & 9% in Africa/Asia)
- Increasing in the US and contributing to billions in cost
Risk Factors of PreE (high)
(most cases occur in healthy nulliparous women with no obvious risk factors) HIGH (recommend LDA if pt has 1 or more) • Multifetal gestations • PreE in a previous pregnancy • Chronic HTN • Pregestational DM (type 1 or 2) • Kidney/renal disease • Autoimmune disease (SLE, APS) Systemic lupus erythematosus, Antiphospholipid syndrome
Risk Factors of PreE (moderate and low)
MODERATE (consider LDA if pt has more than one)
• Nulliparity
• Obesity/BMI (prepregnancy) greater than 30
• Family h/o PreE (mother/sis)
• Sociodemographic (African American, low socioeconomic status)
• AMA >35 years old
• Personal history factors (low birth, SGA, prev adverse pregnancy outcome, >10-year interpregnancy interval)
• Gestational DM
• Thrombophilia
• Assisted reproductive technology
• Obstructive sleep apnea
LOW (do not rec LDA)
Previous uncomplicated full term delivery
Definition of Preeclampsia
• BLOOD PRESSURE - New onset HTN after 20 weeks gestation
o (>140/90 on 2 occasions more than 4 hours apart when BP was previously nml)
o 160/110 (severe htn)
• AND…
• w/ proteinuria
o 300 mg in 24 hr urine or higher
o Protein:creatinine of 0.3 or higher
o Dipstick of 2+ protein
• OR WITHOUT PROTEINURIA AND ONE OF THE FOLLOWING (new onset):
• Thrombocytopenia (less than 100 X10^9/L)
• Renal insufficiency (serum creatinine >1.1mg/dL or doubling of baseline creatinine)
• Impaired liver function (LFTs double the normal concentration)
• Pulmonary edema
• Headache (new onset, not responsive to meds, no other alternative diagnosis)
• RUQ pain, epigastric pain (severe and persistent)
Differential of PreE if < 20 weeks
- Thrombotic thrombocytopenic purpura
- Hemolytic-uremic syndrome
- Molar pregnancy
- Renal disease
- Autoimmune disease
Definition of Preelampsia w/severe features
- 160/110 on 2 occasions >4 hours apart
- Thrombocytopenia (platelet less than 100X10^9/L)
- Renal insufficiency (serum creatinine >1.1mg/dL or doubling of baseline creatinine)
- Impaired liver function (LFTs double the upper limit of normal) w/RUQ/epigastric pain
- Pulmonary edema
- Headache (new onset, not responsive to meds, no other alternative diagnosis)
- Visual disturbances (blurred vision, scotomata, hyper reflexia)
Definition of Gestational Hypertension
• BLOOD PRESSURE - New onset HTN after 20 weeks gestation
o (>140/90 on 2 occasions more than 4 hours apart when BP was previously nml)
o 160/110 (severe GHTN)
o *occurs when hypertension without proteinuria or severe features develops and BPs return to normal in the postpartum period
o Up to 50% of women w/GHTN will develop proteinuria or other end-organ dysfunction consistent with the diagnosis of preeclampsia
More likely if GHTN occurs before 32 weeks
HELLP (Hemolysis, elevated liver enzymes, and low platelet count syndrome)
• More severe form of preeclampsia
o Increased rates of maternal morbidity and mortality
o Mostly in the 3rd TM but 30% of cases expressed/progress postpartum
o Patients may lack HTN and proteinuria
• Diagnosed by:
o LDH (lactate dehydrogenase) over 600 IU/L
o AST (aspartate aminotransferase) and ALT (alanine aminotransferase) elevated more than twice the upper limit of normal
o Platelets less than 100 X10^9/L
• Presents with:
o RUQ pain/malaise – 90%
o N/V – 50%
HELLP treatment
Watch for sudden deterioration in mom/fetus
Women with help should be delivered regardless of gestational age
Need NICU and ICU (obstetric ICU) – transfer to tertiary care center
Tx with corticosteroids helps improve platelets
o Does not improve maternal death, morbidity in mom or fetus
Close monitoring with labs q 12 hours
AST > 2000 and LDH >3000 show increased mortality risk
Supportive care and labs should begin to improve within 4-7 days of delivery
Eclampsia
o Convulsive manifestation of hypertensive disorders of pregnancy
o Defined by new-onset tonic-clonic, focal or multifocal seizures in the absence of other causative conditions (epilepsy, drug use, cerebral arterial ischemia/infarction, intracranial hemorrhage)
o Preceded by persistent occipital/frontal headaches, blurred vision, photophobia, altered mental status in 78-83% of cases
o Preeclampsia evolves to eclampsia in only 1.9% of cases
o Severe preeclampsia evolves to eclampsia in 3.2 % of cases
o Others have no signs preceding eclampsia
Eclampsia treatment
Eclampsia treatment
Supportive measures (eclamptic seizures are usually self-limited)
o Call for help
o Prevent maternal injury
o Place in left lateral decubitus position
o Prevent aspiration
o Administer oxygen
o Monitor vitals
Mag sulfate does not arrest current seizure but prevents them from recurring
o Better than phenytoin, diazepam or lytic cocktail (chlorpromazine, promethazine and pethidine) – less maternal and neonatal morbidity
Refractory treatment for Eclampsia
During seizure – likely to observe prolonged decelerations/bradycardia
After seizure – recurrent decels, tachycardia, diminished variability
When maternal hemodynamic stabilization occurs, proceed with delivery
o Heart tracing should also normalize
o C-section is likely but not a must; consider clinical scenario
May consider:
o Clonazepam 1mg IV
o Diiazepam 10 mg
o Midaazolam
These inhibit laryngeal reflexesinc aspiration risk; use with caution
If pt continues to seize
o Another bolus of magnesium sulfate 2-4 g IV over 5 min X2 doses
If pt continues to seize for 20 min
o Sodium amobarbital 250 mg IV in 3 minutes
o Thiopental
o Phenytoin 1250 mg IV at 50 mg/min (over 15 min)
o Likely need endotracheal intubation, assisted ventilation, ICU, head imaging
Screening for PreE
Biochemical and biophysical markers in 1st and 2nd TM have low PPV
o Those who screen positive will not develop the disease
o A large number of pts would be exposed to testing and not benefit from intervention
o Uterine artery Doppler studies, angiogenic factors, placental growth factor
No single test reliably predicts preeclampsia
Prevention of PreE
No intervention to date has been proven to unequivocally eliminate the risk of preE.
Have tried; VitC, VitE, fish oil, garlic, Vit D, folic acid, sodium restriction, Ca++, bed rest
Imbalance in prostacyclin and thromboxane A2 metabolism
o Aspirin preferentially inhibits thromboxane A2 at lower doses
o Modest risk reduction of PreE when beginning ASA after 16 weeks gestation
Begin LDA 91 mg 12-26 wks until delivery
o More significant reductions in severe PreE and growth restriction
Current studies on metformin, sildenafil and statins
o Not recommended outside of clinical trials
Treatment
Labs
o CBC (platelets), creatinine, LDH, AST, ALT and testing for proteinuria
Consider uric acid if superimposed on chronic HTN
Comprehensive clinical maternal and fetal evaluation
o Ultrasound of fetus
Estimated fetal weight (EFW) and amniotic fluid index (AFI)
• Serial growth US (every 3-4 wks)
Antepartum testing (NST or BPP)
• Weekly to twice weekly
• AFI weekly
Close monitoring of BPs and weekly labs
• Progression from GHTN to PreE w/severe 1-3 weeks
• Progression from PreE to PreE w/severe could happen in days
Decision to deliver balances maternal and fetal risk
May continue pregnancy if diagnosis is GHTN or PreE without severe features
o Until 37 0/7
o HYPITAT trial
After 36 weeks IOL group had reduction in adverse maternal outcome and no differences in rates of neonatal complciations
Balance the risks
o Risks for delayed delivery o Severe HTN o Eclampsia o HELLP syndrome o Placental abruption o Fetal growth restriction o Fetal death
o Benefits for delayed delivery
o Avoid prematurity
o Avoid NICU admission
o Avoid neonatal respiratory complications
Maternal complications in Preeclampsia with severe features
o Pulmonary edema o Myocardial infarction o Stroke o Acute respiratory distress syndrome o Coagulopathy o Renal failure o Retinal injury Thus delivery in the setting of severe features at or beyond 34 0/7
Conditions precluding expectant management
o Maternal
o Uncontrolled severe range blood pressures (160/110 not responsive to tx)
o Persistent headaches (refractory to treatment)
o Epigastric pain or RUQ pain unresponsive to repeat analgesics
o Visual disturbances, motor deficit or altered sensorium
o Stroke
o Myocardial infarction
o HELLP syndrome
o New or worsening renal dysfunction (serum creatinine greater than 1.1 or twice baseline)
o Pulmonary edema
o Eclampsia
o Suspected acute placental abruption or vaginal bleeding in the absence of previa
o Fetal
o Abnormal fetal testing
o Fetal death
o Fetus without expectation for survival at time of diagnosis (lethal anomaly, extreme prematurity)
o Persistent reversed end diastolic flow in the umbilical artery
Proper way to check a blood pressure
o Appropriate sized cuff
o Cuff length 1.5 X the circumference of the arm or bladder encircles 80% of arm
o Taken in an upright position (sitting or in left lateral recumbent)
o After 10 minutes or more of rest
o No tobacco or caffeine in the previous 30 minutes
Intrapartum management
1 Prevent seizures
#2 Control of hypertension
o Magnesium sulfate (smooth muscle relaxant)
o Cuts rate of eclampsia by more than half (in preE w/severe)
• Seizure rate of PreE w/severe 4/200 (4 times higher)
• Treat 36 patients to prevent 1 seizure
Uncertain effect when used in GHTN and PreE without severe)
• Seizure rate of PreE without 1/200
o Reduces the risk of placental abruption
o Slight reduction in the risk of maternal mortality
o Therapeutic range
o 4.8-9.6 mg/dL or 4-8 mEq/L
o Beware of mag toxicity
Magnesium sulfate dosing
o 4-6 g IV loading dose over 20-30 min (10 g IM (5 g in each buttock))
o 1-2 g/hr IV maintenance dose (5 g IM every 4 hours)
Use 1 mL xylocaine 2% due to painful injection
o Continue during surgery (if needed) and for 24 hours postpartum
o REVERSAL with calcium gluconate 10% solution 10 mL IV over 3 min
Add furosemide IV to accelerate urinary excretion
Magnesium sulfate reactions and side effects
o Respiratory depression (12 mg/dL or 10 mEq/L)
o Cardiac arrest (30 mg/dL or 25 mEq/L)
o Loss of deep tendon reflexes (lost at mag level of 9 mg/dL or 7 mEq/L)
o Hot flushes (25%)
o Increased rate of c-section (inc by 5%)
o Measure urine output
(if creatinine 1-1.5 then use only 1 g/hr maintenance)
Serum mag levels every 4 hours
o Follow deep tendon reflexes
o Mag sulfate is the drug of choice
o More effective than phenytoin, diazepam or nimodipine
Contraindications to mag sulfate use
o Myasthenia gravis o Hypocalcemia o Moderate to severe renal failure o Cardiac ischemia o Heart block o Myocarditis
Labetalol
o 10-20 mg IV
o Onset of action in 1-2 min
o Then 20-80 mg IV every 10-30 min
o Max dose of 300 mg (may give constant infusion of 1-2 mg/min IV)
o SE
o Less tachycardia than others
o Avoid in asthma, myocardial dz, heart block, bradycardia, decompensated cardiac function
Outpatient labetalol
o Initiate expeditiously (within 30-60 min) if severe range pressure 160/110 are persistent (>15 min)
o Begin labetalol 200 mg orally every 12 hrs
o Increase up to 800 mg every 8-12 hrs
o Maximum total daily dose of 2400 mg
o If this does not adequately control the pressure then add oral nifedipine
Hydralazine
o 5 mg IV or IM
o Onset of action 10-20 min
o Then 5-10 mg IV every 20-40 min
o Max dose of 20 mg (may give constant infusion of 0.5-10 mg/hr
o SE
o When dosing is higher/more frequent, it leads to maternal hypotension, headaches, abnormal fetal heart rate tracings (more common than others)
Nifedipine
o 10-20 mg orally o Onset of action 5-10 min o Repeat 10-20 mg orally in 20 min o Then10-20 mg every 2-6 hours o Max daily dose of 180 mg o SE o May observe reflex tachycardia and headaches
Anesthesia for PreE
o Regional anesthesia is the preferred technique for women with preE w/severe and eclampsia
o Epidural does not increase c-sec rate, pulmonary edema or renal failure
o Spinal has > hypotension than epidural (51% vs 23%)
o General anesthesia has greater risk
o Aspiration
o Failed intubation due to pharyngolaryngeal edema
o Stroke due to increased intracranial pressures (intubation/extubation)
o But epidural/spinal may not be appropriate due to coagulopathy
Thrombocytopenia increases risk of epidural hematoma
No safe lower-limit for platelets exist but higher than 70 X 10^9 shows low risk of epidural hematoma
o Mag sulfate prolongs nondepolarizing muscle relaxants
½ life of mag sulfate is 5 hours
Does not help to shut off the mag for the c-section (it should continue)
Subsequent risk of cardiovascular disease
With recurrent preeclampsia, the risk is 4-8 times higher than a normal pregnancy
Increased risk of:
o Hypertension (5 times higher)
o Cardiovascular disease (2 times higher)
o Myocardial infarction
o Congestive heart failure
o Cerebrovascular events/ stroke
o Peripheral vascular disease
o Cardiovascular related mortality
Endothelial dysfunction is liked to atherosclerosis
Manage risk factors (achieve healthy weight, exercise, diet, quit smoking)
