Management of Extracorporeal Membrane Oxygenation for Obstetric Patients: Concerns for Critical Care Nurses

The normal, physiological changes that occur during pregnancy and the postpartum period can elevate a woman’s risk for complications that can result in the need for ECMO. For example, the hematologic, cardiovascular, and respiratory systems of a woman’s body undergo profound changes to accommodate the growing fetus.⁵  Normal changes in the hematologic system include a steady and progressive increase in plasma volume of up to 50%; a decrease in hemoglobin, hematocrit, and red blood cell count; and a decrease in platelet count.⁵  Changes also occur in the coagulation systems of pregnant women. During pregnancy and the postpartum period, women are at elevated risk for venous thromboembolism because levels of certain clotting factors increase as levels of endogenous anticoagulants decrease.⁶  These alterations result in a hypercoagulable state in which clotting is more likely.^5,6 

Significant changes also occur in the cardiovascular and respiratory systems. The first change to occur is peripheral vasodilation, which leads to an increase in overall plasma volume. Systemic vascular resistance decreases by as much as 30%, and cardiac output increases by as much as 40% as a compensatory mechanism.⁵  Initially, the increase in cardiac output is caused by enhanced stroke volume; however, as the pregnancy progresses, the increase in cardiac output is caused by increased heart rate.⁷  Blood pressure decreases in the first and second trimesters of pregnancy and is lowest in the second trimester; it rises and returns to prepregnancy levels in the third trimester.⁵ 

During pregnancy, a profound increase in the demand for in oxygen is the result of a 15% increase in metabolic rate and a 20% increase in oxygen consumption.⁵  An increase in tidal volume leads to maternal hyperventilation which in turn leads to an increase in arterial Po₂, a decrease in arterial Pco₂, and a compensatory decrease in serum bicarbonate.⁵  The increased demand for oxygen during pregnancy causes a chronic, respiratory alkalosis, which results in a normal state of compensatory metabolic acidosis.⁵ 

Maternal mortality can be attributed to congenital and acquired CVD, hypertensive disorders of pregnancy, and embolic disorders.⁸  Cardiovascular disease complicates 1% to 3% of all pregnancies; is the cause of 10% to 15% of maternal mortality cases; and includes heart failure, valvular disorders, and arrhythmia.⁹  The increasing number of women with complications related to CVD during pregnancy and the postpartum period may be related to the increasing prevalence of CVD in women of childbearing age.⁷  In addition to preexisting conditions or known CVD, pregnancy-related causes of heart failure include preeclampsia, peripartum cardiomyopathy, and amniotic fluid embolism. Heart failure in pregnancy occurs when cardiac ventricles are unable to handle the increased circulatory demands of pregnancy.⁸  Peripartum cardiomyopathy is relatively rare, has unknown etiology, and is diagnosed within the final months of pregnancy or within 5 months of birth.⁷ 

Valvular disorders or valvular heart disease (VHD) can cause serious complications in women during pregnancy or the postpartum period. Valvular heart disease includes any complication that arises from damage or defects to 1 or more of the 4 heart valves.^7,9  Pregnancy can pose significant health concerns to women with substantial congenital or acquired VHD.⁹  Even with advancements in diagnosis, medical and surgical therapies, and technology, pregnancy and the postpartum period can be complicated by significant adverse maternal and newborn outcomes for women with VHD.⁹ 

Arrhythmia can be caused by preexisting conditions such as cardiomyopathy, valvular disease, congenital changes, or by the pregnancy itself.⁸  Pregnancy can cause ventricular or atrial arrhythmia in women with no prior history of cardiac problems.⁸  Some causes of arrhythmia include changes in hormones, electrolytes (low potassium levels), and the autonomic system; preexisting cardiac disease; and hemodynamic instability.⁸  Whether the CVD is caused by a preexisting condition or by the pregnancy itself, devastating outcomes for mother and/or newborn can occur.

Hypertensive disorders of pregnancy complicate approximately 10% to 15% of all pregnancies and include chronic hypertension, gestational hypertension, and preeclampsia.⁷  Even though all of these conditions are considered hypertensive disorders of pregnancy, it is important for the critical care nurse to be familiar with the slight differences in the origins of each disorder. Chronic hypertension occurs in 1% to 5% of pregnancies and is defined as hypertension that is present before pregnancy, develops before 20 weeks’ gestation, or persists more than 6 weeks after birth.⁷  Gestational hypertension occurs in 5% to 10% of all pregnancies and is defined as the development of hypertension after 20 weeks’ gestation, generally without the presence of proteinuria; it resolves within 6 weeks after birth.⁷  Preeclampsia occurs in approximately 5% to 7% of pregnancies and is defined as the development of hypertension after 20 weeks’ gestation. Preeclampsia differs from gestational hypertension in that it requires the presence of clinically significant proteinuria (> 0.3 g/d).⁷ 

Pregnancy is considered a hypercoagulable state; therefore, during pregnancy and the postpartum period, women are at significant risk for venous thromboembolism, which can present as deep vein thrombosis or as pulmonary embolism.⁷  In addition, during pregnancy and the immediate postpartum period, women are at risk for amniotic fluid embolism (AFE), a rare but significant threat that occurs when amniotic fluid, fetal cells, hair, or debris enters the maternal bloodstream and generates a systemic, allergic reaction.¹⁰  The incidence of AFE was reported to range from 1 in 8000 to 1 in 80 000 births; because of inaccurate diagnosis and inconsistent reporting, the true incidence is unknown.¹⁰  Although maternal mortality rates related to AFE are high, “the infant survival rate is around 70%.”¹⁰  Early diagnosis (possibly attributable to identification of maternal risk factors, increased provider awareness, early recognition of maternal or fetal stress, and prompt resuscitation) and improved resuscitative interventions have resulted in significant reductions in mortality rates.¹⁰  Amniotic fluid embolism is most significantly associated with induction of labor or multiple pregnancies.¹¹  Key signs and symptoms of AFE include shortness of breath, hypotension, hemorrhage, coagulopathy, and premonitory symptoms (numbness, tingling, agitation).¹¹  Although mortality rates have decreased, morbidity rates remain high, and complications include neurological impairment, cardiac failure, renal failure, and respiratory failure.¹⁰  Researchers suggested ECMO as a therapy that could be used to successfully treat women with AFE.¹⁰ 

Early recognition of a patient’s needs and the ability of an institution and its staff to provide ECMO support are vital to ensure positive outcomes. For critical care nurses, caring for patients who require ECMO takes into consideration physical factors, such as risk for thrombosis, bleeding, and infection, and psychosocial factors, such as maternal-infant bonding, family bonding, anxiety, and financial concerns (see Table).¹²  Care for patients undergoing ECMO is labor intensive and requires a team of trained critical care physicians, cardiothoracic surgeons, respiratory therapists, nurse practitioners, critical care nurses, and ECMO specialists or perfusionists. The cardiothoracic surgeon places the cannulas, and the circuit is maintained by the ECMO specialist and the critical care nurse, who routinely monitor the circuit for problems, maintain circuit connections, and evaluate for cracks in tubing.¹²  Mongero et al¹³  found that a multidisciplinary team reduced delirium associated with sedation and functional impairment and improved overall quality of life at discharge for patients undergoing ECMO.

Daily management of these patients includes review and maintenance of mechanical ventilation. Currently, no standard guidelines exist for the management of mechanical ventilation.^14,15  Marhong et al¹⁵  analyzed 141 individual responses from 283 centers across 28 countries, and only 27% of these centers reported the use of explicit, mechanical ventilation protocols for ECMO patients. Most of the centers (77%) reported that lung rest was the primary goal of mechanical ventilation; 9% of the centers reported that lung recruitment was the ventilation strategy.¹⁵  Goals and settings are adjusted as the patient recovers and is able to breathe more independently.

Complications related to the use of ECMO include hematologic complications (thrombosis, bleeding), infection, renal dysfunction, and delirium.¹⁶  Other hematologic complications include thrombocytopenia, acquired von Willebrand factor deficiency, and heightened risk for heparin-induced thrombocytopenia and disseminated intravascular coagulation.¹⁶  Anticoagulation therapy is needed to prevent thrombosis, which occurs in 1% to 22% of patients who receive ECMO¹⁶ ; however, too much anticoagulant will result in bleeding. Currently, standardized guidelines for anticoagulation treatment do not exist, so policies vary among institutions.¹²  Bleeding occurs in 5% to 79% of patients who receive ECMO.¹⁶  In a review of literature on extracorporeal life support during pregnancy, Moore et al¹⁷  found that in fatal hemorrhage cases, bleeding sites were intra-cranial or multiple sites, and in nonfatal cases, bleeding sites were uterine or pulmonary. Other bleeding problems included hemothorax, upper gastrointestinal hemorrhage, maternal intracranial hemorrhage, vaginal bleeding, and bleeding from the cannulation and tracheostomy sites.¹⁷  Because of potential hematologic consequences and the positions and sizes of the cannulas, patients should be monitored for limb ischemia, which occurs in 13% to 25% of patients who receive venous-arterial ECMO.¹⁶  Circulation in the extremities should be checked by monitoring for color, pulses, and capillary refill.

Infection occurs in 17% of 49% of patients who receive ECMO,¹⁶  and bloodstream, respiratory, urinary tract, and catheter-related infections have been reported.¹⁷  Maintaining sterile technique will help reduce the risk of infection, and the critical care nurse should monitor for signs and symptoms of infection.

Renal dysfunction can occur as a result of the hypotension and poor renal perfusion seen in patients under-going ECMO.¹²  Patients who undergo ECMO usually experience decreased urine output related to acute kidney injury caused by multiple system organ failure, use of inotrope and vasopressors to support blood pressure and cardiac output, release of cytokines involved in inflammation, and activation of the complement system.¹⁸  Patients may require continuous renal replacement therapy (CRRT), which is temporary renal replacement for fluid removal or solute clearance.¹⁸  The CRRT tubing can be connected to the ECMO circuit to help improve gas exchange and remove volume.¹⁹  Research on the combined use of ECMO and CRRT has primarily been conducted in pediatric patients, and less work has been done in the adult population.¹⁸  However, in one study of 40 adult patients who received ECMO and CRRT, the mortality rate at 1 month was 80%; among the 8 survivors (20%), 3 patients required continuation of hemodialysis, and 5 patients were independent of dialysis at 30 days.¹⁸ 

Delirium is common in the ICU: it occurs in 32% to 87% of ICU patients and is associated with long-term intellectual problems, increased cost, and increased length of hospital stay.¹²  Delirium can cause altered mental status and sleep deprivation that can heighten the anxiety of the patient’s family.¹²  The signs of delirium range from agitation, restlessness, and combativeness, to being slow to respond to stimuli, to little or complete loss of movement.²⁰ 

When critical care nurses are knowledgeable about the signs of delirium, diagnosis can be made quickly and potential negative side effects can be reduced.²⁰  Delirium can be assessed using the Confusion Assessment Method for the Intensive Care Unit, which takes into consideration mental status changes, inadvertence, level of consciousness, and disorganized thinking.²¹ 

Delirium can be minimized by interrupting sedation daily, encouraging early mobility, structuring patient care activities such has bathing during day hours, and controlling light and noise at night to optimize the patient’s sleep-wake cycle.¹²  The Richmond Agitation-Sedation Scale can be used to minimize amount and depth of sedation needed.²¹  With delirium, the risk that a patient might remove or displace a cannula is a concern because of the potential for exsanguination or air embolism.¹² 

In addition to the potential, physical complications related to the use of ECMO, the critical care nurse must be aware of related psychosocial considerations, such as maternal-newborn bonding and family anxiety.¹²  Maternal-newborn bonding is an emotional connection; interruption of this connection can have negative implications for the mother’s mental health and the newborn’s well-being.²²  In the ICU when a mother is critically ill, bonding, including touching and cuddling, can be difficult, limited, or even nonexistent. If a woman is unable to bond with her newborn in traditional ways, innovative strategies such as video conferencing can allow for visualization of the newborn and other children at home. Hutcheson and Cheeseman²³  described the use of the FaceTime application for parents who were separated from their newborns; based on feedback from parents, the program improved bonding. If the mother is stabilized, placing the naked infant on the mother so there is skin-to-skin contact facilitates bonding²² ; although no studies on ECMO patients using this method were found.

During the postpartum period, women with acute illness may experience anxiety or posttraumatic stress, including feelings of frustration and disempowerment.²⁴  Postpartum depression can negatively affect bonding²⁵  and can cause problems in relationships between the woman and those around her, including members of her support system.²⁶  Nonnenmacher et al²⁵  measured postpartum depression, bonding, and attachment style in women with depression and in healthy women. They found that the combination of depression and dual/disorganized attachment style may pose special risk for the developing mother-infant bond.²⁵  Also, new mothers may view their infant as burdensome and blame the infant for their health care problems.²⁶ 

Critical care nurses also need to consider breastfeeding for obstetric patients after birth. Multiple, short- and long-term medical and neurodevelopmental benefits of breastfeeding have been documented.²⁷  For infants, breast-feeding improves outcomes related to various infections, sudden infant death syndrome and infant mortality, cognitive development, obesity, and diabetes.²⁷  For women, breastfeeding decreases postpartum blood loss, promotes more rapid involution of the uterus, and reduces the likelihood of postpartum depression.²⁷  Cumulative breast-feeding has been correlated with a reduction in breast and ovarian cancer.²⁷  However, breastfeeding may not be appropriate for critically ill women in the ICU. In 1997, Dauphinee and colleagues²⁸  described the information, skills, and resources necessary to assess, initiate, and maintain breastfeeding for critically ill women in the ICU who recently gave birth. They also provided strategies to assist with breastfeeding or pumping as desired.²⁸ 

We were unable to identify any studies on breast-feeding in women who require ECMO. Comfort is a primary concern, especially if an ECMO cannula is placed in the chest. Health care providers do not always encourage breastfeeding for women with chronic illness because of concern that medications may be transferred through breast milk. In addition, in these patients, research by pharmaceutical companies cannot be conducted using clinical trials because of ethical considerations.²⁹  Spencer²⁹  suggested that health care providers refer to LactMed and the Infant Risk Center for the most current information on medications and human milk. After birth, if a woman is unable to breastfeed or pump, her breasts can become engorged and painful. Comfort measures for breast engorgement include ice packs; cold, raw cabbage leaves; and snug-fitting bras or wraps.³⁰ 

Critical care nurses can be a valuable resource for obstetric patients who require ECMO and their family, but little research in this area exists to support best practice. Skoog and colleagues³¹  found that the incidence of anxiety in family members of patients in the cardiothoracic ICU can be as high as 80%. As long as 3 months after discharge, heighted anxiety in a family member can lead to negative psychosocial implications that manifest in what is referred to as post–intensive care syndrome-family.³¹  Anxiety, separation of mother and infant, imposed visiting hours, other siblings, employment obligations, and expenses can all negatively affect bonding.³¹ 

Critical care nurses caring for patients who require ECMO and their family members have valuable resources in palliative care, spiritual care, and critical care social workers. Although long-term implications should be considered before initiation of ECMO, a palliative care and/or spiritual care consult may be needed at a later point.³²  Unfortunately, not all hospitals offer palliative care services.³³  The palliative care team can identify goals to optimize patient care and enhance communication between the patient, family, and all members of the health care team.³²  Enhanced communication and coordination of care can help to mitigate anxiety related to current clinical outcomes and potential death.³²  The spiritual care social worker ensures that religious needs are being met, and the critical care social worker provides psychosocial support, facilitates communication, and provides resources during the hospital stay and for outpatient needs.³⁴ 

Critical care nurses and health care providers in general may experience compassion fatigue related to interactions with the patient and family and in response to negative patient outcomes. Compassion fatigue includes emotional, physical, and psychological symptoms and can ultimately be the reason health care providers leave the profession.³⁵  More research is needed to enhance our understanding of compassion fatigue.

The cases presented at the beginning of this article require quick and decisive interventions. The patient in case 1, with postpartum cardiomyopathy and heart failure, may ultimately require additional mechanical support, a transplant, or may recover completely with no complications. The use of ECMO may save the life of the patient in case 2, who presented with a rare but potentially fatal complication following childbirth. Finally, for the patient in case 3, the use of ECMO may allow recovery from influenza A (H1N1) and the birth of a healthy newborn. All 3 cases are complex and challenging and reinforce the importance of knowledgeable and skilled critical care nurses.

The results of recent studies show that ECMO is an effective and relatively safe treatment for critically ill patients during pregnancy and the postpartum period. In a study of 18 peripartum patients who received ECMO,³⁶  16 patients (88.9%) survived to hospital discharge. Two patients successfully gave birth while on ECMO, and no fetal complications were attributed to ECMO.³⁶  In a literature review, Moore et al¹⁷  reported that 45 patients in 26 studies were treated with ECMO. Survival rates were 77.8% (35 of 45) for mothers and 65.1% (28 of 43) for fetuses. Outcomes for patients in the postpartum period were not included in this review.

It is crucial that patients who require ECMO are identified early and that an experienced and skilled team is involved in their care. The critical care nurse is at the bedside and will be the primary advocate for the patient, family, and newborn. As women continue to give birth later in life and increasing comorbidities complicate medical management, it is likely more obstetric patients will be admitted to the ICU. Education and training regarding this unique patient population should be incorporated at all facilities that provide ECMO so that staff members can respond confidently and competently. CCN