Cases & Commentaries

Acute Respiratory Arrest in Pregnancy

Commentary By Baha Sibai, MD

The Case

A 35-year-old woman was 38 weeks pregnant with
twins (G3P2). When she developed acute onset of shortness of breath
and hemoptysis (coughing up blood), her husband called 911. Shortly
after paramedics arrived, the patient experienced a respiratory and
cardiac arrest. CPR was administered, and she successfully regained
a pulse. Upon hospital arrival, the patient was rushed to the
operating room for emergency C-section. Two infants were delivered
stillborn, with Apgar scores of 0 at 1, 5, and 10 minutes. The
patient was transferred to the ICU with hypoxic encephalopathy; she
eventually recovered.

Review of her medical records revealed that the
patient had a history of chronic hypertension, which had worsened
during her third trimester; it had been managed by increasing the
dose of her chronic antihypertensive medication (labetalol). A few
weeks prior to admission, after the patient complained of shortness
of breath, her obstetrician prescribed her albuterol. Two days
prior to admission, the patient presented to the obstetrics clinic
with blood pressures (BPs) in the range of 170-210/100-125. Fetal
non-stress testing was normal. At that visit, the nursing notes
indicate some concern about preeclampsia. However, the physician
did not order further evaluation, in part because "preeclampsia
labs" had recently been performed and were found normal.

The Commentary

In this case, a woman with chronic
hypertension developed undiagnosed preeclampsia during pregnancy.
Hypertensive disorders occur in approximately 8% of pregnancies and
have been increasing due to changes in obstetric demographics:
obesity, pregnancy at a later maternal age, use of assisted
reproductive technology, and increased rates of twins and
Chronic hypertension rates are approximately 3%-5% and are higher
in pregnant women who are obese, African American, older than 35
years, and who have type 2 diabetes mellitus.(3) The risk of superimposed preeclampsia in patients with
chronic hypertension is approximately 20%; this risk is markedly
increased in patients with twins and in those with type 2 diabetes

Preeclampsia is defined as
hypertension (systolic BP 140 mm
Hg and/or diastolic BP 90 mm
Hg on at least two occasions at least 4-6 hours apart) plus
proteinuria (300
mg/24 hours collection or 1 + on
dipstick on at least two occasions 6 hours apart).(1,2) Superimposed preeclampsia is defined as
chronic hypertension with new onset of proteinuria or onset of
symptoms or abnormal blood tests such as elevated liver enzymes or
low platelet count.(3)
Preeclampsia is further classified as mild or severe. The criteria
for severe preeclampsia are listed in the Table. Risk factors for preeclampsia include
nulliparity, chronic hypertension, previous preeclampsia,
gestational or pregestational diabetes, obesity, and multifetal

Maternal and perinatal outcomes in preeclampsia
depend on several factors: gestational age at onset, severity of
disease process, presence of multifetal gestation, and presence of
preexisting medical conditions such as chronic hypertension or
The primary objective of management in women with preeclampsia must
always be safety of the mother and fetus with delivery of a mature
newborn who will not require intensive and prolonged neonatal care.
This objective is achieved by formulating a management plan that
takes into consideration severity of disease, fetal gestational
age, maternal and fetal status at initial evaluation, and presence
of labor or rupture of membranes (Figure).(1,2)

As seen in this case, common errors in management
include failure to appreciate the clinical significance of signs
and symptoms of severe disease such as shortness of breath and
exacerbation in maternal BPs despite the use of antihypertensive
medication, failure to obtain the appropriate laboratory tests, and
failure to hospitalize for close monitoring and timely
It is important to emphasize that the diagnostic criteria and
management of preeclampsia in women with preexisting chronic
hypertension and twin gestation are different than in normal women
with singleton gestation. In patients with chronic hypertension
and/or those with twins, as in this case, preeclampsia is more
likely to develop early in pregnancy and is more likely to be
severe and to require prompt hospitalization and consideration of
In women with chronic hypertension, the use of antihypertensive
agents removes one of the major indicators of disease progression
(i.e., rising BP). Therefore, inadequate control of maternal BP
with oral medications should lead to prompt hospitalization for
close observation, use of parenteral antihypertensive medications,
and consideration of delivery.(3)

This patient with chronic hypertension and
pregnancy with twins was at very high risk for development of
superimposed preeclampsia and congestive heart failure. As expected
in women with chronic hypertension, this patient's BP worsened
during the third trimester, which required an increase in her
antihypertensive dosing.(3)
Because of her twin gestation, she also had a marked increase in
her plasma volume with resultant increase in her preload (increased
left atrial pressure), leading to pulmonary congestion. When she
complained of shortness of breath a few weeks prior to admission,
she was prescribed albuterol. This was a dangerous error, because
albuterol increases maternal heart rate, leading to reduced
diastolic filling time and increased cardiac work. At the time of
this visit, the patient should have been hospitalized for
evaluation of possible congestive heart failure.

Two days prior to admission, the patient
presented with severe hypertension and probable superimposed
preeclampsia. The required clinical and laboratory evaluations were
not performed despite the fact that the nurse suspected
preeclampsia. But, whatever the results of laboratory tests, a
woman who is further than 37 weeks' gestation with twins and severe
hypertension requires prompt hospitalization, control of BP with
intravenous medications, and delivery (Figure). Because of this error, her pregnancy was
continued, which led to acute alveolar pulmonary edema with
resultant maternal and fetal hypoxia.

How did this error occur? The physician
apparently did not appreciate the significance of severe elevations
in BP as a sign of exacerbation of hypertension or preeclampsia. In
addition, the physician did not obtain required
testing—24-hour urine for proteinuria, platelet count, and
liver enzymes—to rule out superimposed preeclampsia, and
failed to consider hospitalization for delivery at this gestational
age. Moreover, the nurses failed to communicate to the physician
their concern about preeclampsia during the visit 2 days prior to
the acute event, perhaps because they were afraid to question the
knowledge of the physician. While much of the responsibility for
decision-making rests with the physician, the nurses also
demonstrated a lack of knowledge about severe hypertension in
pregnancy by not insisting that the patient remain in the clinic
(or be admitted to the hospital) with these elevated BPs. Summing
up these errors, this case highlights the need for development of
protocols for surveillance and management of hypertension in
pregnancy, including mechanisms to improve education, training, and
methods of communication among all personnel working in the

Several studies have reported on errors and
pitfalls in managing hypertensive disorders in pregnancy.(8-10)
In an Illinois study of 58 cases of hypertensive disorders of
pregnancy, failure to identify high-risk status and incomplete and
inappropriate management by medical providers were associated with
85%-93% of maternal deaths, near-miss events, and severe maternal
morbidity.(8) In
a population-based study of all maternity units in the Netherlands,
errors in diagnosis and management by medical providers
(substandard care) were considered present in 53% of cases that
resulted in severe maternal morbidity.(5) In addition, in a review of all maternal deaths from
hypertensive disease in pregnancy in the Netherlands, errors in
diagnosis and management of severe hypertension were present in 85%
of cases.(10)

Recently, some system approaches
were developed to address these errors.(8,11,12) For example, the Yorkshire guidelines, which
call for standardized protocols for the use of antihypertensive
drugs, monitoring of fluid and urine output, and the use of
magnesium sulfate for seizure prophylaxis, were developed to guide
management of severe preeclampsia (11)
and resulted in reduced rates of maternal morbidity and admission
to intensive care. Similarly, Menzies and colleagues (7)
instituted standardized surveillance for 504 women hospitalized
with preeclampsia. These included orders for type and frequency of
blood tests, fetal monitoring, and surveillance of symptoms and
blood pressure. This program also reported fewer adverse maternal

How can we avoid this type of
error? In managing pregnant women with hypertension, clinicians
must consider all pieces of clinical information at each visit. For
example, given the preexisting conditions of this patient (chronic
hypertension and twins), this patient must be considered at
extremely high risk for adverse outcome. This patient should have
been managed in consultation with or referred to a physician with
expertise in management of her condition, such as a high-risk
specialist. Given her symptoms and need for an increase in dose of
antihypertensive medication, superimposed preeclampsia should have
been strongly considered. Patients with chronic hypertension often
have underlying left ventricular dysfunction as well; in these
patients, it may be difficult to distinguish a worsening underlying
medical condition (exacerbation of hypertension) from superimposed
preeclampsia. My advice is not to agonize about this difference in
the patient at or near term, since delivery is indicated in either
case, which may help resolve the question and avoid progression to
pulmonary edema or stroke. When a patient develops persistent
severe hypertension, intravenous antihypertensive therapy using
agents such as bolus doses of labetalol or hydralazine is indicated
and should be administered promptly. In addition, magnesium sulfate
should be administered to reduce the likelihood of convulsions.
Finally, this case serves as a cautionary note about the importance
of robust nurse–physician communication—its failure in
this case was partly responsible for the error of sending the
patient home prior to establishing the correct


This case illustrates several
key points about enhancing the safety of care provided by
physicians and nurses as it relates to the diagnosis and management
of preeclampsia:

  • Early detection of preeclampsia is
    critical since it may allow for early interventions and timely
    delivery, which will reduce the risk of progression to severe
    preeclampsia, pulmonary edema, eclampsia, stroke, and even
  • To avoid serious adverse outcomes in
    patients with hypertensive disorders of pregnancy, obstetric
    clinics, triage areas, emergency rooms, and hospitals should
    develop protocols, guidelines, and algorithms for diagnosis,
    surveillance, and management. These would include appropriate
    safeguards, such as standardized techniques for measurements of
    weight, blood pressure, urine, and documentation of required
    symptoms and blood tests to be obtained. There should also be
    mechanisms to communicate abnormal clinical and laboratory findings
    to the obstetric providers in a timely fashion.
  • All facilities providing care for
    obstetric or postpartum patients should also develop mechanisms
    that include assessment of competency of medical and nursing
    providers, including channels for communication as well as
    indications for consultation or referrals of complicated cases.
    They should also include procedures for regularly monitoring both
    adherence to protocols and quality of care provided.

Baha Sibai,
Professor of Clinical Obstetrics and Gynecology

Fetal Medicine

University of


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Table. Criteria for Establishing Severe

• Persistent blood pressure above
160/110 mm Hg
• Scotomata/blurred vision
• Nephrotic-range proteinuria (5 g per 24
• Shortness of breath with reduced oxygen
saturation or pulmonary edema
• Refractory oliguria ( • Thrombocytopenia (platelets 3/µL)
• Renal failure (minimal criterion would be a
rise in serum creatinine of 1 mg/dL above baseline)
• Hemolysis (based on peripheral smear
analysis or increased bilirubin)
• Persistent right upper quadrant and/or
epigastric pain
• Impaired liver function of unclear
• Persistent headache • Eclampsia
• Estimated fetal weight below fifth
percentile for gestational age

*In women with preeclampsia, the presence of
any of the criteria will establish a diagnosis of severe


Figure. Management of preeclampsia.