CASE AND COMMENTARY: Acute Respiratory Arrest in Pregnancy
Posted Jun 02 2010 5:00am
Acute Respiratory Arrest in Pregnancy
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.
by Baha Sibai, MD
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 triplets.( 1 , 2 ) 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 mellitus.( 3 )
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 pregnancies.( 1 , 2 )
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 diabetes.( 2 , 4 ) 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 delivery.( 5 , 6 ) 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 delivery.( 2 , 3 ) 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 clinic.( 7 )
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 outcomes.
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 diagnosis.
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 death.
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, MD
Professor of Clinical Obstetrics and Gynecology
Maternal Fetal Medicine
University of Cincinnati
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Table. Criteria forEstablishing Severe Preeclampsia.*