• Nathan Riley, MD

Obgyno Wino Podcast Episode 6 - Gestational Hypertension and Preeclampsia (Part 2)

"The significance of the intimate personal relationship between physician and patient cannot be too strongly emphasized, for in an extraordinarily large number of cases both diagnosis and treatment are directly dependent on it, and the failure of the young physician to establish this relationship accounts for much of his ineffectiveness in the care of patients.” ― Francis Peabody, MD (1927 JAMA article titled ‘The Care of the Patient’

2017 Unoaked Tempranillo from El Jefe

PB#222 - Published June 2020

Intrapartum management

- 2 goals: 1) prevent seizures, 2) control BP

>Seizure prevention

- Magpie study: mag sulfate reduces seizure risk by 50%, also found to decrease maternal mortality and risk of abruption; also increased c/s rate by 5%

- insufficient evidence to support mag sulfate administration for the prevention of preeclampsia progression to severe

- nnt = 129 asymptomatic women

- nnt = 36 symptomatic women (severe HA, blurred vision, photophobia, hyperreflexia, epigastric pain)

- Benzos and phenytoin also may be useful but only if mag sulfate is contraindicated (myasthenia gravis, hypocalcemia, moderate-to-severe renal failure, cardiac ischemia, heart block, or myocarditis) or in context of underlying epileptic disorder

- how to start mag sulfate: 4-6g loading dose then 1-2 g/hr (consider 1g/hr if UOP <30mL/hr for 24 hrs or Cr 1-1.5 mg/dL)

- infusion rates >2 g/hr associated w/ increased perinatal mortality

- continue for 24 hrs after delivery

- No IV? No problem! Administer 5g IM to each buttock followed by 5g q4 hrs; add 1ml of 2% xylocaine to the solution to make the IM injection less painful

Mag toxicity

- principal adverse effects from mag: respiratory depression and cardiac arrest

- increase risk of adverse effects w/ IM administration

- dependent on renal function

- serum mag levels are becoming common place, but PB emphasizes that as long as deep tendon reflexes are present, more serious toxicity is not a concern

- if mag toxicity suspected, stop infusion, re-check serum mag q2 hrs, re-start at lower rate when serum levels return to therapeutic range

- if necessary, correct w/ 10% calcium gluconate 10mL over 3 min + furosemide if renal function intact

Segment 3 - Management of HTN

- antihypertensives should be administered if BPs sustained (2x over at least 15 min apart) in severe range (≥160 mmHg systolic, ≥110 mmHg diastolic)

- if not preparing for delivery, consider starting an oral agent like Nifedipine ER (Procardia XL) once daily or Labetalol 100-200 mg BID/TID uptitrating over time to a max dose of 2400 mg /day, then add hydralazine if a 2nd agent is needed

Mode of delivery

- normal obstetric indications for C/S (even in IUGR!)

- vaginal delivery perfectly reasonably unless delivery needs to be expedited and cervix unfavorable

Segment 5 - Anesthesia considerations

- regional anesthesia OK

- contraindications: platelets <70 as this may carry higher risk of epidural hematoma

- continue magnesium sulfate through the delivery (even for C/S)

- also of note: “induction of general anesthesia and the stress of delivery may even reduce the seizure threshold and increase the likelihood of eclampsia in the immediate postpartum period if the infusion of magnesium sulfate is stopped during delivery”

Postpartum considerations

- keep an eye out for eclampsia, encephalopathy, stroke, and pulmonary edema

- pain management:

-NSAIDs have been of interest recently due to theoretical risk of exacerbating high blood pressures

- recall: how do they work? Decrease prostaglandin production leading to decreased vasodilation and increased sodium retention

- Overall: data don’t support our concerns in using NSAIDs with patients who have underlying hypertensive disorders

- RCT comparing ibuprofen to acetaminophen in PP pts w/ preeclampsia w/ severe features → “ibuprofen did not lengthen the duration of severe-range blood pressures”

- Cohort of 399 pts w/ preeclampsia with severe features, “there was no association of NSAID use with postpartum blood pressure elevations”

- additional cohort of PP patients on mag sulfate for seizure prophylaxis: again no association

Management of eclampsia

- eclampsia should prompt delivery, but it does not mean you have to rush to the OR while she’s seizing

- stabilizing patient generally leads to normalization of the FHR tracing

- protect airway → administer O2 → prevent trauma → fetal monitoring → load mag (2-4 g)

- benzos can be considered if pt extremely agitated

CAUTION: both mag and benzos can inhibit laryngeal reflexes increasing risk of aspiration and depress the CNS leading to apnea

- mag sulfate won’t arrest the seizure but it may prevent recurrence

- once mom is stabilized, decide on delivery plan; if labor is progressing adequately, OK to allow labor to continue even after an eclamptic seizure

- if seizures recur, give another 2-4 g bolus of mag sulfate

- if still seizing after 20 min or ≥2 recurrences, consider amobarbital, thiopental, or phenytoin (and consider head imaging)

Special considerations in HELLP syndrome

- deliver regardless of GA as this condition carries significant rates of maternal morbidity and mortality

- steroids are often given, and it has been hypothesized that these secondarily temporize the pro-inflammatory components of HELLP (“honeymoon period”)

- the data hasn’t quite panned out to support this, so it’s not a recommended therapy to attenuate the underlying disease process in HELLP syndrome

- close monitoring is important event after delivery: ACOG recommends labs q12 hrs

- AST levels >2000 IU/L or LDH >3000 IU/L carry increased mortality risk

- the disease may achieve peak intensity in the first 2 days postpartum; if the platelet count continues to drop or liver enzymes increase after 4 days postpartum, “the validity of the initial diagnosis of HELLP syndrome should be reassessed”

- w/ supportive care alone, 90% of pts will show resolution within 7 days of delivery

Long-term consequences

- gHTN and pre-E carry 2x greater lifetime risk of developed CVD

- pre-E w/ severe features: RR = 5

- risk increase is 4-8x if recurrent preeclampsia or early onset

- 5x greater risk of HTN for any hypertensive condition in pregnancy

- mechanism? Equally poorly understood, but most likely related to endothelial dysfunction

- the question remains: did this underlying dysfunction predispose the patient to hypertensive disease in pregnancy or the other way around?

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