INTRODUCTION — Maternal mortality is higher in the United States than any other resource-abundant country and cardiovascular disease is the leading cause [1,2]. Although the incidence of pregnancy among women with congenital heart disease is increasing, the main cause of cardiac death in pregnancy is acquired heart disease, specifically cardiomyopathy, coronary artery disease, and aortic disorders. Pregnancy-related mortality is most common in women over age 40 years and also among Black women [2,3].
Anesthetic management of the pregnant woman with high-risk cardiovascular disease requires an understanding of the individual patient's cardiac anatomy and pathophysiology; how the physiologic changes associated with pregnancy, labor, and delivery have affected the patient; and the hemodynamic alterations that may be induced by the choices of analgesic or anesthetic techniques. Ideally, an individualized management plan is developed in the antepartum period by the patient’s pregnancy heart team [4-6]. According to the American College of Obstetricians and Gynecologists, a patient’s pregnancy heart team is comprised of obstetric providers, maternal-fetal medicine subspecialists, cardiologists and an anesthesiologist at a minimum [7,8]. Interdisciplinary communication and preparation are critically important since peripartum obstetric and cardiac complications may require rapid intervention.
This topic will discuss general considerations for anesthetic management of the obstetric patient with high-risk acquired or congenital cardiovascular disease, emphasizing methods to minimize peripartum risk while providing optimal anesthetic care. Considerations for anesthetic management of parturients with specific acquired or congenital heart lesions are discussed in a separate topic. (See "Anesthesia for labor and delivery in high-risk heart disease: Specific lesions".)
All other aspects of management of heart disease during pregnancy, including specific cardiac pathology, are discussed separately. (See "Acquired heart disease and pregnancy" and "Pregnancy in women with congenital heart disease: General principles".)
Basic anesthetic considerations for obstetric patients also apply to those with cardiovascular disease. (See "Adverse effects of neuraxial analgesia and anesthesia for obstetrics" and "Pharmacologic management of pain during labor and delivery" and "Neuraxial analgesia for labor and delivery (including instrumental delivery)".)
HEMODYNAMIC CHANGES DURING PREGNANCY, LABOR, AND DELIVERY — Understanding the hemodynamic changes related to pregnancy, labor, and delivery is essential so clinicians can anticipate which cardiac conditions predispose to decompensation in the peripartum period, and select appropriate anesthetic monitoring and techniques to minimize this risk [9].
Antepartum — Cardiovascular and hemodynamic changes begin as early as the fourth week of gestation and persist for several months postpartum. Systemic vascular resistance (SVR) decreases, heart rate (HR) increases by 15 to 20 beats/minute, and preload increases due to an increase in blood volume. These changes result in a 30 to 50 percent increase in cardiac output (CO) above baseline. A physiologic dilutional anemia also develops. Cardiovascular and hemodynamic adaptations to normal pregnancy are summarized in the figures (figure 1A-C) and discussed in detail separately. (See "Maternal adaptations to pregnancy: Cardiovascular and hemodynamic changes".)
Labor — During labor, CO progressively increases due to pain, anxiety, and autotransfusion during contractions. Stroke volume (SV) and HR rise and fall with each contraction, with peaks as high as 30 to 50 percent above prelabor values.
Delivery — Immediately after either vaginal or cesarean delivery, CO peaks as the evacuated uterus contracts and blood from myometrial veins is autotransfused into the systemic venous system. Also, the contracted uterus lifts off the vena cava, resulting in greater venous blood return to the heart, which increases SV. However, blood loss during and immediately after delivery can counteract these effects.
After vaginal delivery, CO and SV increased by 59 and 71 percent, respectively, within the first 10 minutes in one study [10]. These increases in CO and SV persist for at least one hour, while HR decreases and blood pressure (BP) remains unchanged [11]. In combination, these factors typically result in unchanged mean arterial pressure (MAP) in the early postpartum period after vaginal delivery. However, patients with heart failure are at increased risk of developing pulmonary edema.
After cesarean delivery under spinal anesthesia, CO increases by about 25 percent immediately after birth, with partial recovery to pre-cesarean delivery values by the time of fascial closure [12,13].
In patients with cardiovascular disease, other factors that affect hemodynamic status during and immediately after delivery include the underlying cardiac pathology; heart rate and rhythm; gestational age; anesthetic agents; intravascular fluid status; positioning of the patient; and the route, dose, and choice of uterotonic agents. (See 'Effects of drugs commonly used in the labor unit' below.)
PRENATAL ANESTHESIA EVALUATION — Prepartum evaluation includes review of the patient's cardiovascular lesions prior to and after reparative procedures, as well as pertinent cardiac testing to determine risk during peripartum care (table 1). Appropriate monitoring, intravascular access, and anesthetic techniques are planned and explained to the patient.
Risk stratification schemes help identify pregnant women with only mild cardiovascular disease who may safely deliver in a community hospital versus those with high risk who should be transferred to a tertiary care center with maximal resources (table 2 and table 3) [4,5,9,14-24]. Patients with pre-existing cardiovascular disease are at particularly high risk if their pregnancy is complicated (eg, multiple gestation, preeclampsia, venous thromboembolism) [14]. Although the majority of pregnant women with cardiovascular disease have favorable outcomes [25,26], some may experience deterioration in cardiopulmonary status before or during labor and delivery, or in the early postpartum state [22,27]. Contingency plans for obstetric complications are developed by the pregnancy heart team (cardiologists, obstetricians, neonatologists, and anesthesiologists) including planning for emergency cesarean delivery, postpartum hemorrhage, and management of cardiopulmonary complications or cardiac arrest [28,29]. For example, peripartum nitric oxide administration or more aggressive therapies such as cardiopulmonary bypass, extracorporeal membrane oxygenation, ventricular assist devices, or urgent cardiac surgical intervention are occasionally necessary to treat cardiovascular events during labor and delivery. (See "Sudden cardiac arrest and death in pregnancy", section on 'Checklists' and 'Emergency cardiac surgery with concomitant cesarean delivery' below.)
OBSTETRIC ISSUES
Induction of labor — In women at high risk of maternal morbidity or mortality during labor or delivery, scheduling induction rather than waiting for spontaneous labor to begin may ensure that appropriate specialists are readily available (eg, cardiologist, maternal-fetal medicine specialist, obstetric anesthesiologist, and neonatologist). High-risk patients are identified on a case-by-case basis using risk stratification guidelines, and the clinical decision to schedule induction of labor versus allowing spontaneous onset of labor is multidisciplinary.
Induction of labor, if required, is generally safe and usually performed in a conventional manner (eg, cervical ripening with Foley catheter or misoprostol, amniotomy, oxytocin) (see "Induction of labor with oxytocin"). Placement of appropriate maternal monitoring devices (discussed below), intravascular access, and other preparations for analgesia and anesthesia should take place before contractions begin. If an epidural catheter is in place, pain control can be implemented promptly when needed, thus mitigating hemodynamic instability related to the pain and stress of labor.
Women with significant cardiovascular disease should be placed in a semirecumbent position with a lateral tilt during the intrapartum period. Vital signs should be assessed frequently. Cardiac decompensation may mandate initiation of intensive medical management.
Route of delivery — Vaginal delivery is generally preferred unless there is an obstetric indication for cesarean delivery. In high-risk cardiac patients, obstetric management of labor and delivery may be modified to accommodate the limitations imposed by cardiac dysfunction. Neuraxial analgesia is generally considered essential. If neuraxial analgesia is not an option, then the advisability of vaginal delivery may need to be reconsidered.
Maternal warfarin anticoagulation with a therapeutic international normalized ratio before delivery is an indication for cesarean delivery because the fetus is also anticoagulated, increasing the risk of fetal intracranial hemorrhage, particularly during vaginal birth [30,31].
Cesarean delivery is rarely performed solely for a maternal cardiac indication. Exceptions may include aortic dissection, or in some cases, progressive aortic enlargement with ascending aorta diameter >45 mm in a patient with Marfan syndrome since cesarean delivery avoids the repetitive increases in cardiac output (CO) related to contractions and pushing (figure 2A-B) (see "Anesthesia for labor and delivery in high-risk heart disease: Specific lesions", section on 'Marfan syndrome' and "Heritable thoracic aortic diseases: Pregnancy and postpartum care", section on 'Delivery'). Other cardiovascular disorders that may be managed with cesarean delivery include patients requiring rapid intervention and stabilization. However, the method of delivery is always carefully considered and individualized, as discussed in topics addressing each specific cardiovascular lesion.
Vaginal "cardiac delivery" — In a maternal "cardiac delivery" with epidural analgesia, fetal descent during the majority of the second stage is accomplished exclusively by uterine contractions without the aid of maternal expulsive efforts. When the fetal head reaches the pelvic floor, a low or outlet operative vaginal delivery (either forceps or vacuum extraction) is performed. This avoids the physiologic changes associated with maternal pushing (eg, Valsalva maneuver or increased intrathoracic pressure resulting in decreased venous return, decreased preload, and decreased CO). An alternative is to avoid the Valsalva maneuver by instructing the patient to push with an open glottis [32,33].
Some studies indicate that maternal expulsive efforts in cardiac disease are well tolerated, while a prolonged passive second stage and an instrumented vaginal delivery may increase the risk of newborn injury, perineal trauma and maternal hemorrhage [34-36]. Thus, the appropriateness of "cardiac delivery" is controversial. The maternal and fetal risks of operative vaginal delivery relative to the maternal cardiac risk associated with Valsalva maneuvers are individually determined for each patient. (See "Assisted (operative) vaginal birth".)
The anesthesiologist continuously monitors and evaluates maternal hemodynamic tolerance of pushing including pulse oximetry waveform and saturation. This is especially helpful in patients with intracardiac shunts because of the concern for right-to-left shunt with increased intrathoracic pressure (see "Anesthesia for labor and delivery in high-risk heart disease: Specific lesions", section on 'Right-to-left shunting with cyanosis' and "Anesthesia for labor and delivery in high-risk heart disease: Specific lesions", section on 'Left-to-right shuntng'). The resultant decrease in oxygen saturation may stress the fetus. For optimal monitoring, it may be necessary to position the pulse oximetry probe on an earlobe or other area since many women use a handgrip during pushing.
Endocarditis prophylaxis
Effects of drugs commonly used in the labor unit — The following medications are often or routinely used during labor or postpartum [37]. Possible implications for patients with high-risk cardiovascular disease are discussed.
●Oxytocin for labor induction/augmentation or prevention/treatment of postpartum hemorrhage – Oxytocin decreases mean arterial pressure and total peripheral vascular resistance, and possibly causes slight increase in pulmonary artery pressure [38,39]. These changes need to be considered and oxytocin must be administered cautiously to patients with certain cardiovascular lesions (eg, aortic stenosis, hypertrophic obstructive cardiomyopathy, ischemic heart disease, or aortopathy with risk of dissection), since sudden decompensation can occur when afterload is reduced or heart rate is elevated. In these patients, oxytocin is administered as a dilute solution by continuous intravenous (IV) infusion via an infusion pump at a rate of 2.5 – 7.5 IU/hr for elective cesarean delivery (or 7.5-15 IU/hr for intrapartum cesarean delivery) [37,40]. Importantly, oxytocin should not be administered IV as a bolus in patients with cardiovascular disease.
●Misoprostol for cervical ripening or treatment of postpartum hemorrhage – We typically avoid misoprostol in women with a history of vasospastic angina or significant coronary artery disease, unless the benefits are likely to outweigh the risks (eg, uterine atony with hemorrhage). Although vaginal misoprostol has not been shown to affect maternal hemodynamics in healthy women [41], there are very rare reports of cardiovascular events after misoprostol administration [42,43]. The likely cause is coronary vasospasm, as demonstrated with coronary angiography and by successful resuscitation that included administration of nitroglycerin [43,44].
●Carboprost tromethamine for treatment of postpartum hemorrhage – Carboprost tromethamine is avoided in patients with an intracardiac shunt because it may increase shunting due to side effects that include bronchospasm [45] and alterations in the ventilation/perfusion ratio, resulting in increased intrapulmonary shunt fraction and hypoxemia [46].
Carboprost tromethamine is also avoided in patients with single-ventricle physiology as it may significantly decrease CO, which could result in significant morbidity or mortality [47].
Furthermore, carboprost tromethamine may induce hypertension at high doses.
●Methergine for treatment of postpartum hemorrhage – Methergine is contraindicated in patients with cardiovascular disease, especially those with systemic, pulmonary, or pregnancy-induced hypertension, because of the following side effects:
•Vasoconstriction (potentially causing sudden systemic hypertension that can result in stroke, seizure, or myocardial ischemia in patients with hypertension, especially preeclampsia) [48]
•Coronary vasospasm (potentially causing myocardial infarction in patients with ischemic heart disease)
•Increased pulmonary artery pressure (potentially causing shunt reversal and cyanosis in patients with intracardiac shunts)
●Magnesium sulfate for seizure prophylaxis and neonatal neuroprotection – Cardiac dysfunction is associated with very high magnesium levels and appears to be secondary to respiratory arrest and hypoxia [49]. Toxicity can be avoided by standard maternal monitoring during magnesium administration.
●Beta-agonists for treatment of preterm labor or prolonged or frequent uterine contractions – Avoid beta-agonist administration in patients with hypertrophic cardiomyopathy (HCM) since this may cause left ventricular outflow obstruction and decompensation with beta-agonist administration. Beta-agonists should be used cautiously in women with other cardiac lesions, and generally should be avoided in women with heart failure.
Adverse reactions after beta-agonist administration are seen in 1 to 10 percent of patients, including tachycardia, hypertension, and palpitations. In <1 percent, side effects include arrhythmia, cardiac arrest, chest pain, hypotension, myocardial infarction, myocardial ischemia, pulmonary edema, and paradoxical bronchospasm. Alternative tocolytics are available. (See "Inhibition of acute preterm labor".)
●Antihypertensive drugs – Because of preeclampsia clinical trials, antihypertensive agents that are well studied in pregnancy include the calcium channel blocker nifedipine, the beta-blocker with alpha-blocking activity, labetalol, the direct arteriolar vasodilator, hydralazine and the centrally acting alpha-2 agonist, methyldopa (table 4). However, at times, though, a rapidly acting IV vasodilator is necessary to decrease SVR (table 5). Because of its rapid onset and offset, a titrated IV infusion of the calcium channel blocker nicardipine is a reasonable choice to lower blood pressure (BP) during the antepartum, intrapartum periods (table 6). We typically initiate the infusion at 5 mg/hour and titrate it up to 15 mg/hour, waiting approximately ten minutes between dose changes to observe the effects. Another option is an infusion of IV clevidipine if a more rapid and titratable calcium channel blocker is preferred; however, this agent has not been well studied in pregnant patients. In patients with high-risk heart disease, agent selection depends on the specific cardiovascular abnormality. (See "Anesthesia for labor and delivery in high-risk heart disease: Specific lesions".)
Fluid administration during labor — Maintain adequate intravascular volume (preload) and avoid dehydration during labor by allowing intake of moderate amounts of clear fluids throughout labor, as recommended in guidelines published by the American Society of Anesthesiologists [50]. If a laboring patient no longer desires liquids, IV administration of maintenance fluid is initiated at 1 mL/kg per hour and titrated according to clinical assessment of the patient's volume status and hemodynamic response to any fluid boluses.
Additional fluid administration to treat presumed hypovolemia warrants careful monitoring for signs and symptoms of pulmonary congestion. Avoid aggressive fluid administration, particularly in patients with associated preeclampsia. (See "Anesthesia for labor and delivery in high-risk heart disease: Specific lesions", section on 'Cardiomyopathy associated with preeclampsia'.)
GENERAL PRINCIPLES OF ANESTHETIC MANAGEMENT
Intravascular catheters — Filters are placed on all intravenous (IV) catheters in any patient with a known intracardiac or extracardiac shunt to prevent paradoxical air embolism [51]. (See "Anesthesia for labor and delivery in high-risk heart disease: Specific lesions", section on 'Right-to-left shunting with cyanosis' and "Anesthesia for labor and delivery in high-risk heart disease: Specific lesions", section on 'Left-to-right shuntng'.)
Management of implantable cardioverter defibrillators and pacemakers — Patients with cardiovascular disease may have a pacemaker (PM), biventricular PM, and/or implantable cardioverter defibrillator (ICD). For women who are laboring with an ICD, we leave the ICD function on during labor. For emergency cesarean delivery, we leave the ICD on, and we position the dispersive electrode pad ("Bovie pad") for the electrosurgery unit (ESU) on the leg. Although risk of electromagnetic interference (EMI) from the ESU is unlikely during surgery below the level of the umbilicus, we also ensure that a magnet is in the operating room to suspend anti-tachyarrhythmia therapy if necessary. Continuous cardiac monitoring is indicated in these patients [52,53]. Appropriate perioperative management of patients with a PM or ICD is discussed separately. (See "Perioperative management of patients with a pacemaker or implantable cardioverter-defibrillator", section on 'Intraoperative management'.)
Preparation of vasoactive agents — Vasoactive drugs should be prepared in advance, including syringes for bolus administration and infusions for continuous administration. Bolus IV doses of both phenylephrine and ephedrine should be immediately available, as well as a phenylephrine infusion to be administered at 0.1 to 2 mcg/kg per minute if necessary. Depending on the specific cardiac lesion, other vasodilator, inodilator, inotropic, and/or vasopressor drug infusions should also be readily available (table 7 and table 6). Notably, nitroprusside and nitroglycerin are myometrial relaxants; thus, these agents are avoided or used with caution immediately after delivery since they may lead to uterine atony and postpartum hemorrhage. Furthermore, nitroprusside is usually avoided as administration of higher doses may cause fetal cyanide toxicity. (See "Intraoperative management for noncardiac surgery in patients with heart failure", section on 'Hemodynamic management'.)
Management of arrhythmias — In any patients with a history of poorly-tolerated tachyarrhythmias, we place external defibrillator pads to achieve rapid cardioversion or defibrillation. Arrhythmias in the peripartum period are not uncommon in patients with cardiovascular disease. It is important to note that cardioversion or defibrillation is not contraindicated in pregnancy, and fetal intolerance of an arrhythmia, as indicated by fetal bradycardia, is an indication for rapid cardioversion. Management of specific arrhythmias is discussed separately:
●(See "Supraventricular arrhythmias during pregnancy".)
●(See "Ventricular arrhythmias during pregnancy".)
●(See "Maternal conduction disorders and bradycardia during pregnancy".)
●(See "Cardioversion for specific arrhythmias", section on 'Cardioversion during pregnancy'.)
Monitoring — We employ continuous monitoring with a 5-lead electrocardiogram, pulse oximeter with a visible waveform, and intra-arterial blood pressure (BP) catheter during labor or cesarean delivery for most high-risk cardiac lesions [5,9]. Other standard labor monitoring includes noninvasive blood pressure (NIBP) measurement, tocodynamometry, and fetal heart rate (HR) monitoring.
●Electrocardiogram – In all high-risk cardiac patients, a continuous five-lead electrocardiogram (ECG) is monitored for development of arrhythmias, as well as detection of myocardial ischemia in those with ischemic heart disease, aortic stenosis, or hypertrophic cardiomyopathy [54-57]. However, many obstetric nurses are not qualified to interpret ECG monitoring (ie, telemetry). Therefore, it may be necessary to coordinate specialized nursing care for patients at risk during labor. (See "Anesthesia for labor and delivery in high-risk heart disease: Specific lesions", section on 'Ischemic heart disease' and "Anesthesia for labor and delivery in high-risk heart disease: Specific lesions", section on 'Obstructive lesions' and "Anesthesia for labor and delivery in high-risk heart disease: Specific lesions", section on 'Hypertrophic cardiomyopathy (HCM)'.)
●Pulse oximetry – A continuous pulse oximetry monitor with both audible alarms and visible waveform display should be used. This is particularly important for patients with cyanotic congenital heart disease with right-to-left shunting. (See "Anesthesia for labor and delivery in high-risk heart disease: Specific lesions", section on 'Right-to-left shunting with cyanosis'.)
●Intra-arterial catheter – We suggest insertion of an intra-arterial catheter for continuous blood pressure (BP) monitoring before needle placement for neuraxial anesthesia or before induction of general anesthesia in most patients with high-risk cardiac disease. Systemic BP is monitored with an intra-arterial catheter so that hypotension can be detected and treated promptly. During labor, moment-to-moment monitoring of arterial BP allows analysis of the effects of uterine contractions and maternal expulsive efforts on overall hemodynamics. Moreover, because of the potential for emergency cesarean delivery, we suggest that the intra-arterial catheter be inserted during labor in any patient who may suffer hemodynamic compromise during induction of general anesthesia. An intra-arterial catheter also facilitates management of vasoactive drug administration and measurement of arterial blood gases.
●Central venous catheter – Insertion of a central venous catheter (CVC) is not recommended for routine monitoring of intravascular volume status but is prudent if the patient requires vasoactive drug infusions or is at risk for peripartum hemorrhage, as well as for monitoring central venous pressure (CVP).
●Pulmonary artery catheter – A pulmonary artery catheter (PAC) is rarely indicated in parturients with high-risk cardiac disease. The risk of complications (eg, arrhythmias, incorrect interpretation of data, pulmonary artery rupture) is high in this population because of cardiac conduction and anatomic abnormalities. However, a PAC may be helpful in selected patients (eg, severe pulmonary hypertension requiring titration of pulmonary vasodilatory agents such as nitric oxide). In this situation, the patient may undergo labor and delivery in an intensive care unit (ICU) setting or may undergo cesarean delivery in a cardiovascular operating room rather than on a regular obstetric ward. (See 'Emergency cardiac surgery with concomitant cesarean delivery' below.)
●Transesophageal or transthoracic echocardiography – In parturients under general anesthesia, transesophageal echocardiography (TEE) or transthoracic echocardiography (TTE) is indicated to determine the cause of any unexplained persistent or life-threatening circulatory instability (ie, "rescue echo"). (See "Intraoperative rescue transesophageal echocardiography (TEE)".)
Also, TEE monitoring is the best method to assess cardiac volume status (eg, hypovolemia), as well as regional and global cardiac function during general anesthesia. (See "Intraoperative transesophageal echocardiography for noncardiac surgery", section on 'Volume status' and "Intraoperative transesophageal echocardiography for noncardiac surgery", section on 'Ventricular function'.)
ANALGESIA FOR LABOR
Neuraxial analgesia for labor — We suggest a labor epidural, a dural puncture epidural (see "Neuraxial analgesia for labor and delivery (including instrumental delivery)", section on 'Dural puncture epidural analgesia'), or a low-dose combined spinal–epidural (CSE) for most parturients with high-risk cardiovascular disease. (See "Epidural and combined spinal-epidural anesthesia: Techniques".)
A major physiologic benefit of neuraxial labor analgesia in high-risk cardiac patients is reduction in cardiac output (CO) peaks throughout labor since these increases are largely mediated by catecholamine release due to pain and anxiety. Thus, the epidural should be placed early in labor. Ideally, the epidural block is dense enough to minimize any subsequent pain.
For patients in active labor with severe pain, CSE using intrathecal opioid without local anesthetic in the intrathecal space may be preferable to an epidural technique alone because of faster onset of analgesia with minimal hemodynamic effects. For patients in early labor who are relatively comfortable, this difference is less important.
In general, neuraxial approaches are desirable because:
●Excellent analgesia is provided.
●Continuous infusion of local anesthetic and opioid in the epidural catheter may be titrated to meet the needs of the patient as labor progresses. Dense analgesia can be achieved, thus minimizing catecholamine release.
●A passive second stage of labor is possible because the urge to push is diminished. (See 'Vaginal "cardiac delivery"' above.)
●If urgent cesarean delivery becomes necessary, a surgical block can be established with minimal hemodynamic changes by "dosing up" the epidural catheter with more concentrated local anesthetic (typically 2% lidocaine).
Epidural technique for labor
●Perform loss-of-resistance technique with saline (rather than air) to avoid paradoxical air embolism, which can occur if the epidural needle is unintentionally placed into an epidural vein in a patient with an intra- or extracardiac shunt.
●Consider a dural puncture epidural technique to potentially increase the reliability and sacral coverage of the block [58].
●Evaluate the risks and benefits of administering a test dose via the epidural catheter. (See 'Test dose administration' below.)
●Administer a 5 mL dose of the labor epidural solution (eg, 0.04 to 0.125% bupivacaine with 1 to 2 mcg/mL fentanyl) incrementally every five minutes, up to 15 mL. Close monitoring is important to assure adequate labor analgesia.
●If the block remains below T10, and therefore provides inadequate labor analgesia, it is reasonable to administer another 5 to 10 mL of the labor epidural solution.
●If significant labor pain persists 30 minutes after this bolus, it is likely that the position of the epidural catheter is suboptimal and it should be replaced.
●Administer a continuous infusion of the labor epidural solution at a rate of 6 to 12 mL/hour, titrated to maintain adequate analgesia and avoid hypotension.
●It is reasonable to allow a patient-controlled epidural analgesia button for an additional dose of 4 to 6 mL of the infusion as frequently as every 15 minutes, or an epidural pump equipped with programmed intermittent bolus settings. (See "Neuraxial analgesia for labor and delivery (including instrumental delivery)", section on 'Patient-controlled epidural anesthesia' and "Neuraxial analgesia for labor and delivery (including instrumental delivery)", section on 'Programmed intermittent epidural bolus'.)
CSE technique for labor
●Administer 15 mcg of fentanyl into the intrathecal space. Consider eliminating local anesthetic from the intrathecal dose to decrease the likelihood of hypotension.
●If intrathecal local anesthetic is utilized, 1.5 to 2.5 mg of intrathecal isobaric bupivacaine is a reasonable dose. An example of a patient who would benefit from intrathecal local anesthetic is a multiparous patient rapidly progressing into the second stage of labor.
●Initiate administration of a continuous infusion of the labor epidural solution (eg, 0.04 to 0.125% bupivacaine with 1 to 2 mcg/mL of fentanyl) at a rate of 6 to 12 mL/hour, titrated to maintain adequate analgesia and avoid hypotension.
●If labor pain begins to return as the intrathecal fentanyl (with or without local anesthetic) wears off, administer 5 to 10 mL of 0.04 to 0.125% bupivacaine with 1 to 2 mcg/mL of fentanyl in the epidural catheter every five minutes, up to 15 mL total. Other options include patient-controlled epidural analgesia, a technique that permits the patient to self-administer a bolus of epidural drug solution, with or without a continuous background infusion or programmed intermittent pump-delivered boluses. (See "Neuraxial analgesia for labor and delivery (including instrumental delivery)", section on 'Maintenance of labor epidural analgesia'.)
Test dose administration — In patients with cardiovascular disease, we evaluate the risks and benefits of administration of an epidural test dose to assess the possibility of accidental catheter placement into the intravascular or intrathecal space on a case-by-case basis. Test doses typically contain local anesthetic and epinephrine (eg, 3 mL of 1.5% lidocaine with 1:200,000 epinephrine). (See "Epidural and combined spinal-epidural anesthesia: Techniques", section on 'Epidural test dose'.)
Obstetric patients with certain cardiovascular lesions would respond poorly to administration of alpha and beta sympathomimetic agonists (eg, aortic aneurysm or dissection, hypertrophic obstructive cardiomyopathy, or severe mitral or aortic stenosis). Even a small IV dose of epinephrine may result in catastrophic events (eg, marked tachyarrhythmia or hypertension with resultant cardiovascular deterioration). Thus, epinephrine is avoided in such patients, and only a local anesthetic and an opioid are administered to assess for intravascular or intrathecal placement, using one of the following approaches:
●We suggest administering an initial test dose of 3 mL of 1.5% lidocaine with 25 to 50 mcg fentanyl to test for unintentional intravascular or intrathecal placement of the catheter. Intravascular placement would be determined by rapid onset of central nervous system (CNS) symptoms due to lidocaine or fentanyl blood concentrations, while intrathecal placement would be determined by the onset of a spinal block within approximately five minutes.
●Alternatively, the first dose of the labor epidural solution can be the "test dose." In this practice, the first 5 mL of the labor epidural solution (eg, 0.04 to 0.125% bupivacaine with 1 to 2 mcg/mL fentanyl) is administered, and the patient is immediately assessed for CNS excitation symptoms (intravascular placement), then subsequently assessed (five minutes later) for motor block (intrathecal placement).
Whichever technique is chosen, it is important to note that failure to recognize an intravascular injection prior to fully dosing an epidural could result in bupivacaine toxicity and resultant arrhythmias, circulatory collapse, and cardiac arrest. Equally important, failure to recognize an intrathecal injection prior to fully dosing an epidural could result in a high spinal and resultant hypotension, bradycardia, respiratory insufficiency or apnea, loss of consciousness, and cardiac arrest.
Either scenario could be catastrophic for any patient, but this is especially true for patients having limited cardiac reserve. Certainly, proceeding with caution with initial dosing of the epidural is of paramount importance. In fact, it is reasonable to consider each subsequent dose of epidural local anesthetic solution to be a "test dose." Thus, we administer epidural doses in 3 to 5 mL increments every five minutes, while asking the patient for signs and symptoms of an intravascular or intrathecal injection. If there is no evidence of sensory block after a full 15 mL epidural dose has been administered, then the epidural should be replaced.
Parenteral analgesia for labor — Patient-controlled analgesia (PCA) via intravascular opioid infusion with remifentanil or fentanyl in order to achieve optimal pain control and adequate mitigation of catecholamine release may not be a good alternative for patients with high-risk heart disease. Achieving even moderately effective analgesia may require an opioid dose that suppresses ventilation. The resultant carbon dioxide (CO2) retention can cause respiratory acidosis, further catecholamine release, and exacerbation of pulmonary hypertension, arrhythmias, ischemia, or decompensated heart failure.
ANESTHESIA FOR CESAREAN DELIVERY
Neuraxial anesthesia for cesarean delivery — Neuraxial anesthetic techniques are preferred in most patients having cesarean delivery, including those with cardiovascular pathology [5]. (See "Anesthesia for cesarean delivery".)
For most high-risk cardiac patients, a low-dose combined spinal-epidural (CSE) or a slowly titrated epidural anesthetic is reasonable if an intra-arterial catheter has been previously inserted for continuous arterial blood pressure (BP) monitoring.
Purported benefits of the low-dose CSE technique include a slower onset of the neuraxial block, allowing the anesthesiologist to adequately maintain preload and afterload while still achieving the reliability of an intrathecal local anesthetic block. Although data on utilization for delivery in high-risk cardiac patients are limited, we prefer this technique because of the greater reliability of intrathecal (versus solely epidural) local anesthetics for surgical anesthesia. In a case report including four patients with high-risk cardiovascular disease, CSE performed with an intrathecal dose of bupivacaine 4 to 5 mg plus fentanyl 20 to 25 mcg was safe and effective [59]. Administration of this low intrathecal dose is followed by slow loading of the epidural catheter with local anesthetic (eg, 2% lidocaine without epinephrine) to achieve a T6 surgical level.
Epidural technique for cesarean delivery — With or without CSE, placement of the epidural catheter is followed by titration (3 to 5 mL every five minutes) of an agent such as 2% lidocaine. With such titration, as well as appropriate monitoring and vigilance, severe cardiovascular instability is unlikely [60,61]. In patients who may not tolerate sympathomimetic activity, it is important to avoid epinephrine as an additive to the epidural local anesthetic. (See 'Test dose administration' above.)
●In high-risk cardiac patients, especially those with any sort of outflow tract obstruction, place an intra-arterial catheter prior to administration of epidural anesthesia.
●In cardiac lesions where any sudden decrease in preload or afterload can be disastrous, prepare a phenylephrine infusion so that titrated phenylephrine administration can be immediately initiated to treat hypotension. Other vasopressors (eg, ephedrine) should also be readily available, although selection of a specific agent depends on the patient’s underlying cardiac abnormality. (See "Anesthesia for labor and delivery in high-risk heart disease: Specific lesions".)
●Perform loss of resistance with saline, rather than air, to avoid paradoxical air embolism, which could result in stroke in a patient with an intracardiac shunt.
●Evaluate the risks and benefits of administering an epinephrine-containing test dose via the epidural catheter. (See 'Test dose administration' above.)
●Perform left uterine displacement immediately after placement of the epidural. Exaggerating the tilt may be necessary.
●Dose the epidural catheter slowly with a local anesthetic without epinephrine (3 to 5 mL every five minutes) until a T6 level is achieved.
●Fentanyl 50 to 100 mcg via the epidural catheter is often used as an adjunct to reduce intraoperative pain. It is reasonable to administer 100 mcg of epidural fentanyl after the newborn is delivered, or before delivery if there is no fetal compromise.
●Preservative-free morphine 2 to 3 mg or hydromorphone 1 mg via the epidural catheter provides postoperative analgesia. It is reasonable to administer this dose of opioid after the newborn is delivered. We monitor patients receiving long-acting neuraxial opioids for adequacy of ventilation (eg, respiratory rate and depth of respiration), oxygenation (eg, pulse oximetry), and level of consciousness for 24 hours after administration [62]. (See "Post-cesarean delivery analgesia", section on 'Side effects and complications'.)
●During onset of the block, crystalloid is administered to prevent hypotension (co-loading). However, overhydration and rapid preloading (eg, 1000 mL of crystalloid) should be avoided in patients with heart failure. In these patients, reduced volumes of crystalloid and slower administration are appropriate during onset of the block (eg, 250 mL increments with monitoring of the patient's hemodynamic and clinical responses to each increment), and administration of a vasopressor agent (eg, phenylephrine) may be necessary.
●If BP begins to fall, titration of a phenylephrine infusion (0.1 to 2 mcg/kg/minute), phenylephrine boluses (40 to 100 mcg), or ephedrine boluses (5 to 20 mg) are options to counteract the hemodynamic effects of the surgical neuraxial block. Selection depends upon the patient's heart rate (HR) and the specific cardiovascular lesion, although phenylephrine is usually preferred because of lesser potential for fetal acidosis [63].
●If surgery presses beyond an hour, additional 3 to 5 mL epidural doses of 2% lidocaine will likely be necessary.
CSE technique for cesarean delivery — We often select a low-dose sequential CSE for hemodynamically stable, well-hydrated women with high-risk cardiovascular disease undergoing cesarean delivery.
●Administer 2.5 to 5 mg isobaric bupivacaine combined with 15 mcg fentanyl and 0.15 mg preservative-free morphine (or 50 to 100 mcg hydromorphone) into the intrathecal space.
●Subsequently, dose the epidural catheter slowly with a local anesthetic without epinephrine (eg, 3 to 5 mL of 2% lidocaine every five minutes), titrated to a T6 level over approximately 20 minutes.
●With this option, a phenylephrine infusion at 0.5 mcg/kg per minute should be initiated immediately prior to intrathecal injection, particularly in patients at high risk for cardiovascular collapse if vasodilation occurs (eg, hypertrophic cardiomyopathy [HCM]). Phenylephrine is subsequently titrated to keep the patient's BP as close to baseline as possible (the usual range is 0.1 to 2 mcg/kg/minute). Other vasopressors should be readily available if phenylephrine is ineffective (eg, ephedrine [5 to 20 mg boluses], vasopressin infusion); however, selection of a specific agent depends on the patient’s underlying cardiac abnormality (table 7). (See "Anesthesia for labor and delivery in high-risk heart disease: Specific lesions".)
Concerns regarding spinal anesthesia for selected lesions — We avoid a single-shot spinal neuraxial anesthetic technique due to rapid onset of a sympathectomy with sudden decreases in systemic vascular resistance (SVR) and preload, potentially resulting in life-threatening hypotension in patients with these high-risk cardiovascular lesions:
●Severe aortic stenosis or aortic coarctation. (See "Anesthesia for labor and delivery in high-risk heart disease: Specific lesions", section on 'Obstructive lesions'.)
●Severe mitral stenosis. (See "Anesthesia for labor and delivery in high-risk heart disease: Specific lesions", section on 'Obstructive lesions'.)
●Cyanotic congenital heart disease with right to left shunting. (See "Anesthesia for labor and delivery in high-risk heart disease: Specific lesions", section on 'Right-to-left shunting with cyanosis'.)
●Severe dilated cardiomyopathies with low ejection fraction (<30 percent). (See "Anesthesia for labor and delivery in high-risk heart disease: Specific lesions", section on 'Dilated cardiomyopathy'.)
●Hypertrophic cardiomyopathy. (See "Anesthesia for labor and delivery in high-risk heart disease: Specific lesions", section on 'Hypertrophic cardiomyopathy (HCM)'.)
Some anesthesiologists avoid any neuraxial technique in patients with left ventricular outflow tract obstruction [64]. However, careful and well-monitored epidural anesthesia or low-dose sequential combined spinal anesthesia for cesarean delivery has been reported to be well- tolerated, even in parturients with severe aortic stenosis or hypertrophic cardiomyopathy [60,65].
General anesthesia technique for cesarean delivery — A general anesthetic is occasionally needed for cesarean delivery in patients with high-risk cardiovascular disease (see "Anesthesia for cesarean delivery"). The pathophysiology and the desired hemodynamic goals for the patient's specific cardiovascular lesion are considered in selection of anesthetic agents. (See "Anesthesia for labor and delivery in high-risk heart disease: Specific lesions".)
All patients are preoxygenated with 100 percent oxygen, and a rapid sequence intubation is typically performed for cesarean delivery. If a very slowly titrated induction is indicated to maintain hemodynamic stability in a patient with high-risk cardiovascular disease, hemodynamic stability should be prioritized above concerns for aspiration, and the induction should proceed slowly. Although the value of cricoid pressure is debatable, we use it in all inductions for cesarean deliveries. (See "Rapid sequence induction and intubation (RSII) for anesthesia", section on 'Preoxygenation' and "Rapid sequence induction and intubation (RSII) for anesthesia", section on 'Cricoid pressure during RSII'.)
A reasonable approach for induction in many patients with cardiovascular disease is use of a short-acting hypnotic (eg, etomidate [0.2 to 0.3 mg/kg], ketamine [1 to 2.5 mg/kg], or propofol [1.5 to 2.5 mg/kg, in divided doses, titrated to effect] with phenylephrine boluses [50 to 100 mcg] or phenylephrine infusion [0.1 to 2 mcg/kg/minute]). However, considerations in choosing induction agents vary based on the individual cardiovascular lesion and pregnancy complications. For example, ketamine should be avoided in preeclamptic patients because of the sympathetic stimulation (see "Anesthesia for labor and delivery in high-risk heart disease: Specific lesions", section on 'Cardiomyopathy associated with preeclampsia'). Succinylcholine 1 to 1.5 mg/kg is administered for paralysis.
Although preinduction treatment with lidocaine (50 to 100 mg) and opioids such as fentanyl (1 to 2 mcg/kg), is typically avoided in cesarean delivery in order to maximize neonatal respiratory drive at birth, patients with cardiovascular disease may benefit from administration of these agents to blunt the sympathetic response to laryngoscopy and intubation. Maternal hemodynamic stability is the priority, rather than the usual obstetric anesthesia concerns regarding neonatal sedation. If fentanyl and lidocaine are administered as adjunct agents during and after induction, the neonatal team should be notified so that preparations are made for possible respiratory support of the newborn. For some patients, the ultra-short acting agent remifentanil (1 to 2 mcg/kg) is administered during and after induction to avoid tachycardia without risk of causing prolonged neonatal respiratory depression [66,67]. (See "Perioperative uses of intravenous opioids: Specific agents", section on 'Remifentanil'.)
For maintenance of general anesthesia, sevoflurane or desflurane is administered at approximately 1 minimum alveolar concentration (MAC) value as tolerated. If desflurane is selected, rapid increases in concentration are avoided, as this may cause tachycardia and pulmonary hypertension. Nitrous oxide (N2O) is avoided in all patients prior to delivery, and is not used at all in patients with elevated pulmonary artery pressures or intracardiac shunts. (See "Maintenance of general anesthesia: Overview", section on 'Inhalation anesthetic agents and techniques'.)
EMERGENCY CARDIAC INTERVENTIONS
Mechanical circulatory support in pregnancy — There are increasing reports of the use of mechanical circulatory support (MCS) such as extracorporeal membrane oxygenation (ECMO), intraaortic balloon pumps, and ventricular assist devices (VADs) in pregnancy, labor, delivery, or during the postpartum period [68-71].
Initiation of extracorporeal membrane oxygenation — Severe respiratory failure or pulmonary hypertension crisis may necessitate initiation of venovenous or venoarterial extracorporeal membrane oxygenation (ECMO) to improve oxygenation, hypercapnia, and/or shock [68,70,72-80]. Most commonly, venovenous ECMO has been employed to treat respiratory failure (eg, due to influenza or COVID-19 infection) [81]. Venoarterial ECMO has also been used in parturients with pulmonary embolism, cardiac failure, or acute pulmonary hypertensive crisis [73-76,82,83]. In the largest case series that included any type of ECMO used in the United States from 1999 to 2014, 331 obstetric patients and 20,123 nonobstetric patients were identified [80]. The most common indications for ECMO in obstetric patients were sepsis (22.1 percent), cardiomyopathy (16.6 percent), and aspiration pneumonia (9.7 percent). In this series, in-hospital all-cause mortality was lower in obstetric ECMO patients compared with nonobstetric ECMO patients (adjusted odds ratio [aOR] 0.78, 95% CI 0.66-0.93) [80].
In selected patients at extremely high risk of requiring peripartum ECMO support, venous and arterial micro puncture catheters may be placed prior to delivery to facilitate rapid placement of ECMO cannulas if acute decompensation occurs. Details of ECMO initiation and management, and the role of transesophageal echocardiography (TEE) during insertion are discussed in other topics:
Insertion of intraaortic balloon pump or ventricular assist device — Use of an intra-aortic balloon pump (IAPB) or a ventricular assist device (VAD) as a life-saving option for parturients with acute or end-stage chronic heart failure has become more common [68,70,71,84,85]. Initiation and perioperative management of these devices are discussed in other topics:
●(See "Intraaortic balloon pump counterpulsation".)
●(See "Anesthesia for noncardiac surgery in adults with a durable ventricular assist device".)
Emergency cardiac surgery with concomitant cesarean delivery — Certain acute cardiac events result in life-threatening hemodynamic instability (eg, acute onset of severe mitral or aortic regurgitation [ie, due to endocarditis], acute myocardial infarction, acute prosthetic cardiac valve thrombosis or dysfunction, pulmonary embolism, or ascending aortic dissection). In such cases, immediate cardiovascular surgical intervention with cardiopulmonary bypass (CPB) may be necessary. It is important that the pregnancy does not delay life-saving treatment for the mother. If the fetus is viable, the cardiac surgical procedure may be combined with cesarean delivery.
POSTPARTUM CARE — The intensity of postpartum monitoring is determined by the patient's underlying cardiovascular disease and any obstetric or cardiac events that occurred during labor and delivery [5]. Women with lesions such as pulmonary hypertension, intracardiac shunt, peripartum cardiomyopathy, or a dilated aorta due to Marfan syndrome are at particularly high risk for morbidity and mortality during the postpartum period [86,87]. Details regarding management of postpartum care in patients with high-risk cardiovascular disease are discussed in separate topics. (See "Overview of the postpartum period: Normal physiology and routine maternal care" and "Pregnancy in women with congenital heart disease: General principles", section on 'Postpartum care' and "Acquired heart disease and pregnancy", section on 'Postpartum care'.)
SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Perioperative cardiovascular evaluation and management" and "Society guideline links: Obstetric anesthesia".)
SUMMARY AND RECOMMENDATIONS
●Hemodynamic changes during pregnancy, labor, and delivery – Understanding these hemodynamic changes allows the anesthesiologist to anticipate decompensation in the peripartum period in patients with cardiovascular lesions, and to select appropriate anesthetic monitoring and techniques to minimize this risk. (See 'Hemodynamic changes during pregnancy, labor, and delivery' above.)
●Prepartum anesthetic evaluation – Evaluation includes review of the patient's cardiovascular lesions prior to and after reparative procedures, as well as review of recent cardiac testing. Appropriate monitoring, intravascular access, and anesthetic techniques are planned and explained. (See 'Prenatal anesthesia evaluation' above.)
●General principles for anesthetic management
•Intravascular catheter filters – Filters are placed on all intravenous (IV) catheters in any patient with a known intracardiac or extracardiac shunt to prevent paradoxical air embolism
•Management of ICD or pacemaker – We leave an implantable cardioverter defibrillator (ICD) on during labor. For emergency cesarean delivery, we leave the ICD on, and we position the dispersive electrode pad on the leg. Although risk of electromagnetic interference (EMI) from the electrosurgery unit (ESU) is unlikely during surgery below the level of the umbilicus, we also ensure that a magnet is in the operating room to suspend anti-tachyarrhythmia therapy if necessary. (See "Perioperative management of patients with a pacemaker or implantable cardioverter-defibrillator", section on 'Intraoperative management'.)
•Vasoactive agents – Vasoactive drugs are prepared (table 7 and table 6). Notably, nitroprusside and nitroglycerin are typically avoided immediately after delivery since these myometrial relaxants may lead to uterine atony and postpartum hemorrhage. (See 'Preparation of vasoactive agents' above.)
•Management of arrhythmias – External defibrillator pads for rapid cardioversion or defibrillation if history of poorly tolerated tachyarrhythmias.
•Monitoring (see 'Monitoring' above):
-Continuous pulse oximetry throughout active labor with a visible and audible waveform.
-Telemetry if increased risk for arrhythmias; computerized ST-segment trending if risk for myocardial ischemia.
-Intra-arterial catheter for continuous blood pressure (BP) monitoring before induction of general anesthesia or needle placement for neuraxial anesthesia.
-Other invasive cardiovascular monitoring (eg, central venous catheter [CVP], transesophageal echocardiography [TEE]) may be employed in selected patients.
●Neuraxial analgesia for labor – We employ an epidural or combined spinal-epidural (CSE) for most parturients with high-risk heart disease (Grade 2C). In selected patients, techniques for test dose administration are modified to avoid administration of local anesthetic containing epinephrine as an additive. (See 'Epidural technique for labor' above and 'CSE technique for labor' above and 'Test dose administration' above.)
●Anesthesia for cesarean section
•Neuraxial analgesia – We employ neuraxial anesthesia with a low-dose CSE or a very slowly titrated epidural anesthetic in most patients having cesarean delivery, including those with cardiovascular pathology (Grade 2C). (See 'CSE technique for cesarean delivery' above and 'Epidural technique for cesarean delivery' above.)
We avoid single-shot spinal anesthesia for cesarean delivery in selected high-risk patients (eg, severe aortic or mitral stenosis, cyanotic congenital heart disease with right-to-left shunting, dilated cardiomyopathies with severe ventricular dysfunction [ejection fraction <30 percent], hypertrophic cardiomyopathy) because of the potential for life-threatening hypotension due to rapid onset of a sympathectomy with sudden decreases in systemic vascular resistance (SVR) and preload. (See 'Concerns regarding spinal anesthesia for selected lesions' above.)
•General anesthesia – A general anesthetic is occasionally needed for cesarean delivery in patients with high-risk cardiovascular disease. The pathophysiology and the desired hemodynamic goals for a specific cardiovascular lesion are considered in selection of anesthetic agents. (See 'General anesthesia technique for cesarean delivery' above.)
●Need for emergency cardiac intervention
•Mechanical circulatory support – Development of cardiorespiratory instability may require initiation of venovenous or venoarterial extracorporeal membrane oxygenation (ECMO) or insertion of an intraaortic balloon pump (IABP) or ventricular assist device (VAD). (See 'Mechanical circulatory support in pregnancy' above.)
•Cardiac surgical procedure – Acute cardiac events resulting in life-threatening hemodynamic instability (eg, ascending aortic dissection, acute onset of severe mitral or aortic regurgitation, acute myocardial infarction, prosthetic cardiac valve thrombosis, pulmonary embolism) may necessitate life-saving cardiac surgical intervention for the mother. If the fetus is viable this procedure may be combined with cesarean delivery. (See 'Emergency cardiac surgery with concomitant cesarean delivery' above.)
●Postpartum care – Intensity of postpartum monitoring is determined by the patient's underlying cardiovascular disease and any obstetric or cardiac events that occurred during labor and delivery. (See 'Postpartum care' above.)
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