Page 749 - ACCCN's Critical Care Nursing

726 S P E C I A LT Y P R A C T I C E I N C R I T I C A L C A R E

gathered retrospectively. 119,122 A relatively recent prospec- are required before this specific therapeutic intervention
tive population-based study in the Netherlands found is adopted for routine management.
that 1 in 20,000 pregnancies required ICU admission for For women diagnosed with peripartum cardiomyopathy
peripartum cardiomyopathy. 7
whilst pregnant, timing and mode of delivery are two
The exact cause of peripartum cardiomyopathy is not well other management decisions to be made. A multidisci-
understood and a variety of factors have been implicated, plinary team, including cardiologist, obstetrician, anaes-
including viral infection, autoimmune mechanisms, thetist and nursing/midwifery staff, should consider and
cytokine-mediated inflammation, increased myocyte plan for delivery dependent on maternal and fetal condi-
apoptosis, increased oxidative stress, genetic disposition tion and the woman’s known preferences. Ergometrine-
and/or cultural habits, and abnormal hormonal regula- containing drugs, used to contract the uterus post-delivery,
tion. 121,123 Maternal mortality associated with peripartum are contraindicated because they cause vasoconstriction
cardiomyopathy is around 15%, however, it may be as and the associated increase in afterload may be detrimen-
low as 2% in developed countries. 124 Studies show that tal for maternal heart function. Synthetic preparations,
approximately 20–40% of women recover their left such as oxytocin, are advised instead to prevent post-
ventricular function, usually within six months though partum haemorrhage. Finally, given the postulated role
it may take up to two years. 120,125 Women who never of prolactin in the aetiology of peripartum cardiomyo-
fully recover their cardiac function require ongoing pathy, recent guidelines advise against breastfeeding
medical management; a small proportion of women go in women who have been diagnosed with peripartum
on to require a mechanical-assist device and heart cardiomyopathy. 120
transplantation.
Subsequent Pregnancy
Management and Treatment Priorities Family planning counselling is an important part of the
Women with peripartum cardiomyopathy present with care of women as they recover from peripartum cardio-
varying degrees of left heart failure. Signs and symptoms myopathy. As indicated earlier, left ventricular function
of heart failure including dyspnoea, persistent cough, may take over two years to recover and women, after a
abdominal discomfort, palpitations and oedema may be diagnosis of peripartum cardiomyopathy, are at risk of a
mistaken for ‘discomforts of pregnancy’ and lead to a relapse in any subsequent pregnancy. Generally speaking,
delay in diagnosis. The diagnosis of peripartum cardio- women who become pregnant following a diagnosis
myopathy is one of exclusion requiring systematic of peripartum cardiomyopathy have approximately a
investigation to exclude both cardiac and non-cardiac 30% risk of relapse. 125,131 Peripartum cardiomyopathy
differential diagnoses such as pulmonary embolism, remains an important cause of maternal death and this
acute myocardial infarction, severe preeclampsia and may occur in association with subsequent pregnancies.
pneumonia. 126 Echocardiography is a useful diagnostic
tool with a left ventricular end-diastolic diameter >60 mm EXACERBATION OF MEDICAL DISEASE
120
predictive of poor recovery, as is a LVEF <30%. When ASSOCIATED WITH PREGNANCY
available, a cardiac MRI allows for better chamber volume
and functional assessment and is a more sensitive tool to Women with preexisting medical conditions pose addi-
identify a left ventricular thrombus. 120 tional challenges during pregnancy. In a population-
Management of peripartum cardiomypothy is centred on based prospective study of all pregnant and postpartum
optimising cardiac function and preventing complica- admissions to ICU in the Netherlands, 28% of women
7
tions. The principles of managing acute heart failure in had at lease one chronic disease. However, this preexist-
women with peripartum cardiomyopathy are no different ing medical condition may not have been related to the
to the management of heart failure from any other cause, need for ICU admission. For example, in an Australian
and aims to reduce preload and afterload and to increase study 39% of admissions to ICU had a medical history,
cardiac contractility (see Chapter 10 for a full descrip- but the preexisting illness was related to the ICU admis-
10
tion). Unfortunately, ACE inhibitors and angiotensin sion in 24% of women. Occasionally pregnant and
antagonists are contraindicated in pregnancy, and are postpartum women are admitted to ICU with exacer-
usually not prescribed. bation of an underlying medical condition and two of
the most common conditions, asthma and cardiac
Bromocriptine, a relatively new and novel treatment for disease, are outlined in this section.
peripartum cardiomyopathy, is still undergoing investiga-
tion and as such is not routinely prescribed. Recent ASTHMA
advances in understanding the aetiology of peripartum
cardiomyopathy have suggested that increased oxidative Epidemiology and Course of Asthma
stress plays a significant role and bromocriptine is directly During Pregnancy
able to reduce oxidative stress by blocking the release of Asthma is the most common chronic health disease in
prolactin. 127 Animal and early human studies show pregnant women, affecting 4–8% of all pregnancies in the
promise, with relapse of peripartum cardiomyopathy pre- US. 132 However, the incidence in Australia may be higher
vented in women in a subsequent pregnancy and rapid given the higher prevalence, 12–14%, of ‘current asthma’
recovery in new-onset peripartum cardiomyopathy in women of childbearing age. 133 The course of asthma
observed. 128-130 Larger studies confirming these findings during pregnancy is highly variable and not predictable