Cardiac Arrest in Pregnancy

Today we discuss a topic that we hope you never encounter, but want every OB, EM, and really any other person or medical professional to be prepared for cardiac arrest in pregnancy. The American Heart Association (AHA) Scientific Statement on Cardiac Arrest in Pregnancy can be found here and is essential companion reading.

(c) AHA

In preparation for a maternal cardiac event, a cesarean delivery kit should be available as part of the adult code cart. This at minimum should have a scalpel (#10 blade), betadine splash prep, clamps for cutting the umbilical cord, sponges, absorbable suture, and additional clamps and/or retractors if feasible. A neonatal resuscitation cart should accompany the adult cart if a maternal code is ongoing.

BLS is not different from standard for any other adult resuscitation, except for one key component: leftward displacement of the uterus. This allows for improved venous return to the right heart via the inferior vena cava, which may be compressed to some degree as early as 12 weeks gestation. Otherwise hand positioning, compression technique, and ventilation considerations in the BLS portion do not have any differences.

The ACLS algorithm also proceeds as usual, with the notable exception being performance of resuscitative hysterotomy (aka, peri-mortem cesarean section) at 4 minutes of pulseless arrest. This should be performed at any gestation above 20 weeks (i.e., fundal height at or above the umbilicus). It serves the dual purpose of improving maternal venous return, as well as protecting the fetus from consequences of prolonged anoxia.

Otherwise, ACLS algorithms use the same medications and doses, the same indications for shocks, and actually many times the same etiologies for arrest. However there are some pregnancy-specific considerations all physicians should recall, in a simple mnemonic:

(c) Society of Obstetric Anesthesia and Perinatology


Breastfeeding Part II: Facts and Myth-busting

Today we (finally!) sit down with Part II of our breastfeeding special with Dr. Erin Cleary to cover myths, facts, and advantages of breastfeeding.

There are only three main contraindications to breastfeeding:
1. In infants with galactosemia.
2. In mothers who are HIV+ in high-resource settings.
3. In mothers with human T-cell lymphoma virus.

There are a number of relative contraindications to breastfeeding:

  • In a mother with Hepatitis A until she receives gamma globulin.

  • In a mother with Hepatitis B until the infant receives HBIG and HepB vaccine.

  • In a mother with Hepatitis C if coinfections present, such as HIV.

  • In a mother with Varicella zoster (Chicken pox) while mother is infectious.

  • In a mother with Active TB until mother has received 2+ weeks treatment

  • In a mother with influenza

    • if the mother has been afebrile without antipyretics for >24 hours, and the mother is able to control her cough and respiratory secretions.

    • Oseltamivir or Tamiflu is poorly excreted in breastmilk

  • In patients abusing IV drugs.

  • In patients using marijuana:

    • (THC), the main compound in marijuana, is present in human milk up to eight times that of maternal plasma levels, and metabolites are found in infant feces, indicating that THC is absorbed and metabolized by the infant

    • Several preclinical studies highlight how even low to moderate doses during particular periods of brain development can have profound consequences for brain maturation, potentially leading to long-lasting alterations in cognitive functions and emotional behaviors

    • Breastfeeding mothers should be counseled to reduce or eliminate their use of marijuana to avoid exposing their infants to this substance and advised of the possible long-term neurobehavioral effects from continued use

Common Breastfeeding Myths/Misconceptions:

Infectious:

  • You should breastfeed if you have mastitis, emptying the breast prevents stasis of milk

You can breastfeed in setting of acute respiratory, urinary, GU infections, continuation of BF acceptable

Imaging Sudies

  • You can breastfeed if… You need medical imaging.

    • XRays do not affect milk

    • Mammograms may be harder to interpret when a patient is lactating, but this should not be a reason to defer recommended diagnostic imaging

    • CT/MRI with or without contrast do not impact breastmilk

    • XRays with contrast dye or imaging with radioactive material are also OK

    • Exception: thyroid scan using I-131

      • I-131 concentrates in breastmilk and at high levels can suppress baby’s thyroid function (or even destroy the thyroid) and increase risk of thyroid cancer.

      • Therefore it is important that breastfeeding be discontinued until breastmilk levels are safe (this depends upon the dose and ranges from 8 days to 106+ days). The half-life for I-131 is 8.1 days.

      • Hale recommends that when I-131 is used, breastmilk samples should be tested with a gamma (radiation) counter before breastfeeding is resumed to ensure that radiation in the milk has returned to safe levels.

  • You can breastfeed if… You are pregnant!  

    • Increasing progesterone will decrease supply and cause breast/nipple sensitivity.  

    • Mature milk will be replaced by colostrum in the 2nd trimester.

    • Tandem feeding includes breastfeeding a newborn and toddler

  • You can breastfeed if… You’ve had general anesthesia.  As soon as you are awake enough to hold the baby, the medication has metabolized and breastfeeding is safe.

  • You can breastfeed if… You are on maintenance medications such as methadone and buprenorphine

    • There is a reduction in severity and duration of treatment of NAS when mothers on these medications breastfeed

  • You can breastfeed if… You have an occasional alcoholic beverage

    • Alcohol concentration in the blood is in steady state with the milk, so delaying nursing or pumping until more alcohol is metabolized can limit exposure

  • If direct breastfeeding is interrupted due to temporary separation of mother and child for any reason, the breastfeeding mother should be encouraged and supported to regularly express her milk.

    • Expression and storage of milk allows the infant to continue to receive milk if appropriate, and prevents stasis of milk and mastitis

In the setting of infection, prior to expressing breast milk, mothers should wash their hands well with soap and water and, if using a pump, follow recommendations for proper cleaning.

Cardiotocography/EFM Part II: Management

Today we are back with our midwifery colleagues Linda Steinhardt and Liz Kettyle, who shepherd us through the management of cardiotocography in labor.

We start this episode by quickly reviewing definitions, and defining categories of tracings, reviewed below:

Copyright UpToDate

Recall that category I tracings virtually exclude fetal acidemia, while category III tracings are associated with acidemia 25% of the time, but also have higher risk of cerebral palsy, neurologic injury, or fetal death. That said, the positive predictive value for bad outcomes of CTG is overall poor.

We review a number of scenarios and resuscitative measures for category II and III tracings. However, much of this episode draws on the 2013 Clark et al. article to describe the management of category II tracings. The algorithm is below:

Clark et al. (AJOG 2013)

Hypertension and Pregnancy Trio

We’ve had an overwhelming response to our Espresso episode on acute treatment of severe hypertension in pregnancy, so today we have a special triple episode release on pregnancy and hypertension! We dive into ACOG PB 202 on Preeclampsia and Gestational Hypertension, and ACOG PB 203 on Chronic Hypertension in Pregnancy (membership required for both).

In our first episode, we dive into risk factors and definitions to set the stage. Recall several risk factors that may raise your suspicion for these disorders:
- Nulliparity
- Multiple gestation
- Chronic hypertension
- History of hypertensive disorder of pregnancy in previous pregnancy
- Pregestational or gestational diabetes mellitus
- Thrombophilia, Anti-phospholipid syndrome, or SLE
- Chronic kidney disease
- Advanced maternal age > 35 years
- Obesity (BMI > 30) or obstructive sleep apnea
- Conception via assisted reproductive technology

In episodes 2 and 3, we dive into the specific definitions and management for each hypertensive disorder. Here are our show notes in table format; we hope that this helps you with your own review!

And in closing, a few postpartum/future health pearls to consider:
- With a history of any of these hypertensive disorders, baby aspirin is indicated in future pregnancies beginning at 12 weeks gestation to reduce risk or delay onset of preeclampsia.
- Women with a history of preeclampsia have 3-4x higher lifetime risk of hypertension, and 2x lifetime risk of heart disease and stroke, thus its important to ask about these even with just the annual physical.
- Best available evidence suggest NSAIDs are OK to use postpartum for patients with hypertensive disorders of pregnancy.
- Best available evidence also supports use of parenteral magnesium for seizure prophylaxis in patients who develop any of these disorders during the postpartum period (generally onsets within first week, but has been reported up to 8 weeks after delivery!).

Further reading from the OBG Project:
And get updates on this and more content, as well as other awesome features for FREE if you’re a PGY-4 — sign up for OBG First!
Diagnosing Preeclampsia: Key Definitions and ACOG Guidelines
ACOG Preeclampsia Guidelines: Antenatal Management and Timing of Delivery
Aspirin Treatment for Women at Risk for Preeclampsia: ACOG and USPSTF Guidelines
Chronic Hypertension in Pregnancy: Diagnosis and BP Measurement
Chronic Hypertension in Pregnancy: Evaluation and Management
The 2017 AHA/ACC Blood Pressure Guidelines
#GrandRounds: Does Hypertension in Pregnancy Predict Hypertension in Later Life?

Espresso: Treatment of Acute Hypertension in Pregnancy and Postpartum

Our second espresso episode focuses on the acute treatment of severe-range BPs in the pregnant and postpartum patient. More or less, we let the freshly released ACOG CO 767 speak for itself.

Below you’ll find the algorithms we describe in the podcast, which are present in ACOG CO 767. In addition to the below, always remember:

-Obtain IV access and labs (CBC, Creatinine, AST, ALT, urine protein:creatinine ratio) for any newly diagnosed patient with severe-range pressures.
-Avoid labetalol in patients with known asthma, as the beta-blockade effect can trigger respiratory issues, as well as those with CHF or pre-existing cardiac disease. Labetalol may also cause neonatal bradycardia due to beta-blockade.
-Immediate-release nifedipine should not be administered sublingually due to possibility of developing precipitous hypotension. Similarly, parenteral hydralazine may also cause precipitous maternal hypotension.
-IV magnesium sulfate should be given at a 4g or 6g bolus initially, followed by 2g/hr drip for the prevention of eclamptic seizures, if not previously given. Adjusted dosing may be required if renal insufficiency is noted on laboratories. Magnesium sulfate is not an antihypertensive agent.