Version May 2024
INTRODUCTION — Preeclampsia is a multisystem disorder with unique concerns for the anesthesiologist in the peripartum period. This topic will discuss the anesthetic management of labor and delivery for preeclamptic patients, including labor analgesia, cesarean delivery, fluid management, and invasive monitoring. The pathogenesis, clinical features and diagnosis, and obstetric management of patients with preeclampsia are discussed separately. (See "Preeclampsia: Clinical features and diagnosis" and "Preeclampsia: Antepartum management and timing of delivery" and "Preeclampsia: Pathogenesis".)
PREANESTHESIA EVALUATION — Preeclamptic patients should be evaluated by an anesthesia clinician early in labor, with the expectation that an emergency delivery may be required at any time. Patients with preeclampsia are at an increased risk for life-threatening events, including placental abruption, cerebral hemorrhage, pulmonary edema, acute kidney injury, hepatic failure or rupture, disseminated intravascular coagulation, and progression to eclampsia. (See "Preeclampsia: Clinical features and diagnosis".)
The preanesthesia evaluation of these patients should focus on severity of disease, the airway examination, hemodynamic status, and coagulation parameters, all of which may change over time.
Severity of preeclampsia — Preeclampsia may be classified as severe (also called preeclampsia with severe features) or preeclampsia without severe features (table 1). (See "Preeclampsia: Antepartum management and timing of delivery".)
In general, peripartum anesthesia for patients with preeclampsia without severe features is managed as it would be for patients without preeclampsia, recognizing that severity may increase at any time. Patients with preeclampsia without severe features may or may not receive magnesium for seizure prophylaxis. (See 'Intraoperative magnesium' below and "Preeclampsia: Intrapartum and postpartum management and long-term prognosis", section on 'Seizure prophylaxis'.)
Airway evaluation — Airway management may be particularly difficult in preeclamptic patients who are prone to edema and bleeding with airway instrumentation. Airway edema may worsen over the course of labor, and may be present even with a reassuring airway examination. Airway evaluation is discussed separately. (See "Airway management for the pregnant patient" and "Management of the difficult airway for general anesthesia in adults".)
Equipment necessary for difficult and emergency airway management should be available on the labor floor; urgent or emergency airway intervention may be required not only for general anesthesia for cesarean delivery, but also for airway protection if eclamptic seizures occur, or in the setting of magnesium toxicity or overdose. (See "Airway management for the pregnant patient", section on 'Equipment preparation'.)
Hemodynamic status — Hypertension is generally the earliest clinical finding in preeclampsia, and may be treated in the peripartum period with oral and/or intravenous vasodilators (eg, nifedipine, labetalol, hydralazine), which may affect the choice of vasoactive drugs administered during analgesia and anesthesia. (See "Treatment of hypertension in pregnant and postpartum patients", section on 'Acute therapy of severe hypertension'.)
With severe preeclampsia, patients may develop cardiac dysfunction, myocardial damage, and pulmonary edema, which may affect the choice and dose of anesthetic medications, and the need for invasive monitoring. (See "Preeclampsia: Clinical features and diagnosis", section on 'Pulmonary edema'.)
Coagulation — Patients with severe preeclampsia and/or HELLP syndrome (Hemolysis, Elevated Liver enzymes, Low Platelet count) may develop thrombocytopenia, which increases the risk of spinal epidural hematoma with neuraxial anesthesia techniques. Both the absolute platelet count, and the trend in the count over time are important considerations for the timing and advisability of neuraxial procedures. The platelet count necessary to safely perform neuraxial anesthesia is unknown [1], and practice varies. In the absence of other coagulation abnormalities, neuraxial anesthesia procedures are generally safe for patients with a platelet count ≥70,000/microL, with close follow-up for signs of spinal epidural hematoma (algorithm 1) [2,3]. We generally avoid neuraxial procedures in patients with a platelet count <50,000/microL, in whom the risk of spinal epidural hematoma is likely elevated. For patients with a platelet count between 50,000 and 70,000/microL, we make an individualized decision based on the clinical scenario and risk factors [3]. (See "Adverse effects of neuraxial analgesia and anesthesia for obstetrics", section on 'Neuraxial analgesia and low platelets'.)
Use of low dose aspirin should not affect the decision to use neuraxial techniques. This is of interest because the United States Preventive Services Task Force [4] and the American College of Obstetricians and Gynecologists [5] recommend use of low-dose aspirin for prevention of preeclampsia in patients deemed high-risk. Risk factors for preeclampsia and the use of aspirin for prophylaxis are discussed in detail separately. (See "Preeclampsia: Prevention", section on 'Low-dose aspirin'.)
Other coagulopathies may develop, including disseminated intravascular coagulation, as well as liver function abnormalities, and may also preclude the use of neuraxial techniques. Coagulation testing, other than a platelet count, should be individualized based on patient factors (eg, liver function test abnormalities, abruption). Changes in prothrombin time (PT), partial thromboplastin time (PTT) and fibrinogen do not occur in most preeclamptic patients with a normal platelet count [6,7].
We do not transfuse patients with platelets solely to allow neuraxial anesthesia. However, if the obstetrician administers platelet transfusion prior to cesarean delivery, there may be an opportunity for neuraxial anesthesia. Indications for platelet transfusion and correction of coagulopathy are discussed separately. (See "Preeclampsia: Intrapartum and postpartum management and long-term prognosis", section on 'Management of thrombocytopenia'.)
CARE SETTING: ICU VERSUS LABOR FLOOR — Patients with preeclampsia may require invasive monitoring and intensive care during the peripartum period. The decision to care for these patients on the labor floor, or in the intensive care unit (ICU), should be institution specific, collaborative between anesthesia, obstetric, and nursing teams, and based on available resources and clinical expertise.
Advantages of care on the labor floor include:
●Proximity of the obstetric, neonatal, and obstetric anesthesia teams, for rapid response to changing clinical situations
●Familiarity of the nursing staff with intrapartum assessment of labor, fetal monitoring, and the drugs, procedures, and interventions frequently used during labor and delivery
Advantages of the intensive care unit for these patients include:
●Familiarity with invasive monitoring and vasoactive infusions
●Superior resources for maternal resuscitation
In some institutions, the best compromise may be to cross cover, with obstetric and ICU nurses sharing patient care in the most appropriate unit.
HEMODYNAMIC MONITORING — Blood pressure may be labile, and change rapidly in patients with preeclampsia, due to disease progression, administration of vasoactive medications, the pain of labor, or anesthetic interventions. Invasive hemodynamic monitoring (ie, arterial catheterization, central venous catheter placement) is not routine for these patients, but may be indicated in some circumstances.
●Arterial catheterization – A radial artery catheter should be considered prior to induction of general anesthesia for patients with severe preeclampsia based on blood pressure, if time permits, to provide continuous blood pressure monitoring and rapid response to adverse changes, especially during rapid sequence induction and during emergence. (See 'General anesthesia' below and 'Goal blood pressure' below.)
Radial artery catheters are not routinely placed for hemodynamic monitoring during labor for patients with preeclampsia. However, radial artery catheterization is a low-risk procedure [8] that may be beneficial for continuous blood pressure monitoring, and facilitates blood sampling [9]. Placement of an arterial line should be considered in the following situations:
•Persistent, severe hypertension (eg, systolic blood pressure >160 or diastolic blood pressure >110) refractory to treatment [9-11]
•Use of vasoactive infusions to control blood pressure
•Need for frequent blood sampling (eg, patients with coagulopathy, hemorrhage, severe renal or hepatic dysfunction), particularly for patients with difficult peripheral venous access
•Need for frequent arterial blood gas monitoring (eg, patients with pulmonary edema and hypoxia)
•For use of a minimally invasive cardiac output monitor to guide hemodynamic management [12] (see "Intraoperative fluid management", section on 'Dynamic parameters to assess volume responsiveness')
●Central venous catheterization – Central venous catheters (CVCs) and pulmonary artery catheters (PACs) are rarely used in parturients with preeclampsia. Indications for placement are similar to those for patients without preeclampsia, including difficult peripheral venous access, central administration of vasoactive infusions, and measurement of cardiac function and/or preload. (See "Basic patient monitoring during anesthesia", section on 'Other monitors of circulation'.)
However, complication rates for central line placement are relatively high in patients with severe preeclampsia [13,14], and there are no randomized trials to support the use of CVCs [15]. Placement of a CVC or PAC takes time, and should not delay delivery for patients with severe preeclampsia.
Central venous pressure correlates poorly with pulmonary capillary wedge pressure in patients with preeclampsia [16-18]. Therefore, a PAC should be placed if measurement of preload is the primary objective.
●Transthoracic echocardiography – Transthoracic echocardiography (TTE) is safe in pregnancy [19] and may be useful in assessing cardiac function in the setting of hypertension, hemodynamic instability, or respiratory failure [20]. TTE may also be used to assess volume status and guide therapeutic management in obstetric patients with preeclampsia [21]. TTE requires specialized training and frequent use to maintain competency.
GOAL BLOOD PRESSURE — For preeclamptic patients, we aim to keep the patient's blood pressure close to her baseline, rather than normal blood pressures, to preserve uteroplacental perfusion, but always less than systolic 160 mmHg and diastolic 110 mmHg. Blood pressures >160/110 mmHg should be lowered aggressively, while monitoring the fetus to be sure that uteroplacental perfusion is maintained and late decelerations do not develop. The medications and doses used for treatment of acute, severe hypertension are shown in a table (table 2).
Though specific blood pressure targets are not supported by data, goals for blood pressure management for preeclamptic patients should include:
●Avoidance of severe hypertension to reduce the risk of stroke and intracranial hemorrhage – Severe systolic hypertension is associated with stroke in these patients in the peripartum period [11]. A review of 28 patients with stroke associated with severe preeclampsia found that 100 percent of the patients had systolic blood pressure (BP) greater than 155 mmHg before the stroke [9]. Ninety-three percent of the strokes were hemorrhagic events, 54 percent of the patients died, and all but three of those who survived suffered permanent disability.
●Avoidance of hypotension to maintain uteroplacental perfusion – Uteroplacental perfusion may be compromised in patients with preeclampsia, and may increase the risk of fetal compromise with hypotension. (See "Preeclampsia: Clinical features and diagnosis", section on 'Pathogenesis'.)
INTRAVENOUS FLUID MANAGEMENT — Peripartum fluid administration should be monitored closely, since patients with severe preeclampsia are at risk for pulmonary edema. The etiology of pulmonary edema in these patients may be multifactorial, including myocardial dysfunction as a result of acutely increased systemic vascular resistance, low colloid oncotic pressure with capillary leak, and iatrogenic fluid administration. (See "Preeclampsia: Clinical features and diagnosis", section on 'Pulmonary edema' and "Preeclampsia: Intrapartum and postpartum management and long-term prognosis", section on 'Fluids'.)
Current obstetric practice is to limit total fluid administration in patients with severe preeclampsia to 80 to 100 mL/hour intravenous (IV), including oxytocin and magnesium infusions. Restrictive volumes of fluid should also be administered during initiation of neuraxial labor analgesia or neuraxial anesthesia, and during anesthesia for cesarean delivery. (See 'Fluid administration' below.)
In most patients who receive low dose local anesthetic with opioid solutions for neuraxial labor analgesia (eg, 0.0625 to 0.125% bupivacaine with fentanyl), no IV bolus is required or advised to prevent hypotension [22-24]. (See "Neuraxial analgesia for labor and delivery (including instrumental delivery)", section on 'Goals for neuraxial drug choice' and "Adverse effects of neuraxial analgesia and anesthesia for obstetrics", section on 'Hypotension'.)
The limited available data do not indicate an absolute maternal or fetal benefit of colloids over crystalloids for obstetric patients in general [25,26], or for preeclamptic patients in particular [27-29].
LABOR ANALGESIA — In the absence of other contraindications, neuraxial analgesia is the preferred form of labor analgesia for patients with preeclampsia [30].
For patients in whom neuraxial analgesia is contraindicated (eg, severe coagulopathy), other options include systemic analgesics and nitrous oxide. (See "Pharmacologic management of pain during labor and delivery", section on 'Opioid analgesia' and "Pharmacologic management of pain during labor and delivery", section on 'Nitrous oxide'.)
Advantages of neuraxial labor analgesia — Some advantages of neuraxial labor analgesia are particularly relevant for patients with preeclampsia.
●Superior pain relief, compared with systemic analgesics [31]
●Attenuation of the hypertensive response to labor pain
●Reduction of circulating catecholamines [32]
●Possible improvement in placental blood flow [33-35]
●Provision of a means for rapid conversion to surgical neuraxial anesthesia, with avoidance of general anesthesia
Neuraxial analgesia versus systemic opioids — For patients without preeclampsia, the effects of neuraxial labor analgesia on the progress and outcome of labor, and on maternal and fetal outcomes, have been studied extensively. (See "Adverse effects of neuraxial analgesia and anesthesia for obstetrics", section on 'Effects on the progress and outcome of labor'.)
Several randomized trials have reported no difference in the mode of delivery or neonatal outcomes for patients with preeclampsia who received epidural labor analgesia, compared with systemic analgesia.
●In one study, 200 preeclamptic parturients were randomly assigned to epidural analgesia (0.125% bupivacaine with tramadol, administered by intermittent bolus) or intramuscular tramadol for labor analgesia [36]. There were no differences in hypotension, cesarean delivery rates, or neonatal apgar scores.
●In another study, 116 parturients with severe preeclampsia were randomly assigned to epidural analgesia (bolus of 0.25% bupivacaine, followed by infusion of 0.125% bupivacaine with fentanyl) or intravenous (IV) meperidine [37]. There were no differences in the cesarean delivery rate or neonatal outcomes. Infants of patients who received meperidine were more likely to require naloxone, and parturients who received epidural analgesia were more likely to require ephedrine for hypotension.
●In one small study, 30 preeclamptic patients were randomly assigned to epidural analgesia (bolus of 0.25% bupivacaine, followed by infusion of 0.125% bupivacaine with fentanyl) or remifentanil patient controlled intravenous analgesia [38]. There were no differences in maternal vital signs, neonatal outcomes, or mode of delivery.
●In a single center trial, 738 parturients with pregnancy-induced hypertension (diastolic blood pressure ≥90 mmHg, with or without other features of preeclampsia) were randomly assigned to epidural analgesia (bolus of 0.25% bupivacaine followed by infusion of 0.125% bupivacaine with fentanyl) or intravenous meperidine for labor analgesia [39]. Epidural analgesia was associated with an increase in forceps delivery (14 versus 7 percent) but no difference in the cesarean delivery rate or in neonatal outcomes.
Management of neuraxial labor analgesia — Techniques for neuraxial labor analgesia for preeclamptic patients are the same as for patients without preeclampsia, and are discussed separately. Differences in management for preeclamptic parturients are discussed here. (See "Neuraxial analgesia for labor and delivery (including instrumental delivery)".)
Timing of neuraxial analgesia — We place an epidural catheter early in labor for patients with preeclampsia. Early placement is especially important for patients with declining platelet counts before severe thrombocytopenia occurs, and for patients with expected difficulty with airway management. (See 'Advantages of neuraxial labor analgesia' above.)
The epidural test dose — The administration of a test dose with epinephrine after epidural catheter placement in obstetrics is controversial, and practice varies. (See "Neuraxial analgesia for labor and delivery (including instrumental delivery)", section on 'The epidural test dose in obstetrics'.)
For preeclamptic patients, alternative test dose solutions, without epinephrine, may be used (eg, fentanyl, or air) (see "Neuraxial analgesia for labor and delivery (including instrumental delivery)", section on 'The epidural test dose in obstetrics'), since epinephrine test doses may be unreliable (eg, for patients who have received beta blockers), or may cause severe hypertension if inadvertent intravascular injection occurs. One author avoids an epinephrine test dose for preeclamptic patients, and tests the epidural catheter by administering a dilute epidural solution of local anesthetic and opioid, assessing for the onset of appropriate block. The other author administers an epinephrine containing test dose (eg, 3 cc of lidocaine 1.5% with epinephrine 1:200,000). If 15 mcg epinephrine is used for a test dose in a patient with severe preeclampsia, the provider must be prepared to treat severe hypertension emergently in the event of an intravascular injection or even rapid absorption.
Vasopressors during neuraxial analgesia — Blood pressure may be labile during labor, and after administration of labor analgesia. Vasodilators, vasopressors, and beta blockers are commonly required in preeclamptic patients. (See 'Hemodynamic status' above and "Treatment of hypertension in pregnant and postpartum patients", section on 'Choice of therapy'.)
When needed, vasopressors (eg, ephedrine, phenylephrine) should be administered in small doses (eg, ephedrine 2.5 to 5 mg IV, phenylephrine 25 to 50 mcg IV) to preeclamptic patients, and titrated to effect, as their responses to these medications may be unpredictable. Preeclamptic patients are more sensitive to various vasopressors, including norepinephrine [40] and epinephrine [41] and require lower doses of ephedrine and phenylephrine to reverse spinal hypotension [42-44].
Epidural catheter removal — Removal of the epidural catheter may cause epidural blood vessel injury that could lead to spinal epidural hematoma. The catheter should not be removed unless the platelet count and coagulation studies are at a level that would allow neuraxial needle insertion. (See 'Coagulation' above.)
ANESTHESIA FOR CESAREAN DELIVERY — Cesarean delivery (CD) may be performed with neuraxial anesthesia (ie, spinal, combined spinal-epidural [CSE], or epidural) or general anesthesia.
Intravenous access — We place two intravenous (IV) catheters, including at least one large bore catheter (ie, 18 gauge or larger), to facilitate administration of magnesium, vasoactive infusions, oxytocin, IV fluid, and blood products as well as our anesthetic medications.
Choice of anesthetic technique
General versus neuraxial anesthesia — Neuraxial anesthesia is preferred for preeclamptic patients who undergo CD, rather than general anesthesia, whenever possible. The most important advantage to neuraxial anesthesia is that it avoids the severe hypertension, which may be life threatening, that may occur during induction of and emergence from anesthesia. (See 'Goal blood pressure' above.)
In addition to the advantages of neuraxial anesthesia for CD in non-preeclamptic patients, considerations for patients with preeclampsia include the following:
●Neuraxial anesthesia avoids the need for endotracheal intubation, which may be difficult in these edematous patients.
●Neuraxial anesthesia avoids the need for administration of neuromuscular blocking agents, which are potentiated by magnesium. (See 'Intraoperative magnesium' below.)
●Neuraxial anesthesia may cause more hypotension than general anesthesia, but it is usually transient and easily treated, without a difference in neonatal outcome [45,46].
Choice of neuraxial technique — The choice of neuraxial anesthetic technique (ie, spinal, epidural, or CSE) should be based on patient factors and the clinical context. Spinal and CSE are often used when a labor epidural catheter has not been in place.
Historically, spinal anesthesia was avoided in patients with severe preeclampsia because of the possibility of profound hypotension related to the rapid onset of sympathetic block. (See "Adverse effects of neuraxial analgesia and anesthesia for obstetrics", section on 'Hypotension'.)
A number of studies have refuted these concerns, including the following:
●In one trial, 80 patients with severe preeclampsia were randomly assigned to general, epidural, or CSE for CD [46]. There were no differences in mean highest or lowest blood pressures, or neonatal outcomes, with any of the anesthetic techniques.
●In another trial, 100 severely preeclamptic patients were randomly assigned to epidural or spinal anesthesia for CD [47]. Hypotension was more common in the spinal group (51 versus 23 percent). However, the duration of significant hypotension (systolic blood pressure [BP] ≤100) was brief (≤1 minute) in both groups and was easily treated with small doses of ephedrine.
●A retrospective review of 140 severely preeclamptic patients who underwent CD reported no difference in lowest blood pressures between spinal and epidural anesthesia, with no difference in maternal or fetal outcomes [48].
Patients with preeclampsia may be at lower risk for spinal induced hypotension than patients without preeclampsia. Two prospective case controlled studies of severely preeclamptic patients who underwent cesarean delivery at term [43] and preterm [42] reported lower incidences of spinal hypotension and ephedrine requirement in the preeclamptic patients.
Anesthetic management of neuraxial anesthesia — The techniques and doses of neuraxial medications for preeclamptic patients are similar to those for parturients without preeclampsia, and are discussed separately. (See "Anesthesia for cesarean delivery", section on 'Neuraxial anesthesia'.)
Concerns specific to preeclamptic patients are discussed here.
Fluid administration — IV fluid co-loading during placement of neuraxial anesthesia should be avoided or minimized (ie, <500 mL crystalloid solution IV) for patients with severe preeclampsia. Intraoperative fluid administration should be conservative as well. (See 'Intravenous fluid management' above.)
Vasopressors during cesarean delivery — Vasopressors (eg, phenylephrine and/or ephedrine) are routinely administered during initiation of spinal anesthesia to prevent spinal hypotension. These medications should initially be administered in low, incremental doses, titrated to effect, in patients with preeclampsia, aiming for a blood pressure close to baseline. The choice of vasopressor should be based on maternal hemodynamics, since the selection of specific vasopressors has not been shown to affect maternal or fetal outcomes in patients with preeclampsia [49,50].
A reasonable strategy to prevent neuraxial anesthesia-induced hypotension for patients with preeclampsia includes prophylactic, titrated administration of low-dose phenylephrine infusion (ie, starting at <50 mcg/min) with rescue boluses of either phenylephrine (eg, 25 to 50 mcg IV) or ephedrine (2.5 to 5 mg IV), aiming for a blood pressure close to baseline, or systolic <160 mmHg. For patients with baseline bradycardia, ephedrine (5 to 10 mg IV bolus, or 1 to 5 mg/min IV infusion) may be administered as an alternative. The choice of vasopressors for treatment of spinal hypotension is discussed in more detail separately.
Phenylephrine and ephedrine are the most commonly used vasopressors to address hypotension during CD due to their long history of use and excellent maternal and fetal safety profile. However, use of norepinephrine is an area of active investigation, and there is a growing body of evidence to support its safety and noninferiority to other agents in both healthy pregnancy and in patients with preeclampsia [51-53]. (See "Anesthesia for cesarean delivery", section on 'Vasopressors'.)
Uterotonic medications — Uterotonic medications are routinely administered after delivery of the fetus during both vaginal and cesarean delivery. Oxytocin is the first line medication, followed by other uterotonics if bleeding persists. (See "Postpartum hemorrhage: Medical and minimally invasive management", section on 'Administer additional uterotonic medications'.)
The dose of oxytocin required to achieve adequate uterine tone may be increased in preeclamptic patients who receive magnesium infusions [54].
Methylergonovine can cause severe hypertension, and should not be administered to patients with preeclampsia [55]. For postpartum hemorrhage unresponsive to oxytocin administration, prostaglandins (ie, misoprostol or carboprost) should be administered. Carboprost should be avoided in patients with asthma.
General anesthesia — General anesthesia may be indicated for emergency cesarean delivery with a reassuring airway examination, or for patients with severe coagulopathy such that neuraxial anesthesia is contraindicated. The basic management technique for general anesthesia for cesarean delivery is discussed separately. Concerns specific to preeclamptic patients are discussed here. (See "Anesthesia for cesarean delivery", section on 'General anesthesia'.)
Airway management — In most patients, including those with preeclampsia, endotracheal intubation is performed after rapid sequence induction of anesthesia. Difficulty with airway management must always be anticipated, with equipment and personnel available to manage a difficult or failed airway. (See 'Airway evaluation' above and "Management of the difficult airway for general anesthesia in adults" and "Airway management for the pregnant patient".)
Induction of anesthesia — Induction of anesthesia should always include steps to minimize or eliminate the hypertensive response to laryngoscopy and intubation. This hemodynamic response may be exaggerated in preeclamptic patients, and may result in intracranial hemorrhage and/or pulmonary edema [56,57]. We place an arterial catheter in patients with severe range blood pressures for continuous blood pressure monitoring prior to induction of general anesthesia, if time permits, to facilitate rapid response to changes in blood pressure.
In addition to the usual anesthesia induction agents, a variety of medications may be administered during induction to blunt the hemodynamic response to intubation, with a target blood pressure of systolic <160 mmHg and diastolic <110 mmHg [11]. In general, drugs with rapid onset and short duration of action are preferred. The literature on the choice of medication and optimal doses in this setting is limited [58]. Thus, medications are chosen based on patient factors, and clinician preference.
Our usual drug regimen for induction of anesthesia is as follows:
●Preinduction, labetalol 10 mg IV boluses, titrated to achieve systolic blood pressure <160 mmHg, if time permits.
●Propofol 2 mg/kg IV
●Succinylcholine 1 mg/kg IV
●Nitroglycerin infusion, or Nicardipine (100 mcg/mL, 1 to 2 mL bolus), as needed during induction, with goal systolic blood pressure <160 mmHg.
Medications that may be used to blunt the hypertensive response to intubation include the following:
●Labetalol titrated with 10 mg IV boluses up to 1 mg/kg prior to induction [59]
●Esmolol 2 mg/kg IV during induction, or 1 mg/kg IV with lidocaine [60]
●Nitroglycerin 1.5 to 2.5 mcg/kg IV [61,62]
●Nicardipine 15 to 30 mcg/kg IV, or 100 to 200 mcg bolus during induction [63]
●Remifentanil 1 mcg/kg IV during induction [64,65], crosses the placenta and may cause transient neonatal respiratory depression
●Fentanyl 1 to 3 mcg/kg IV [66]
Opioids are generally avoided during induction of anesthesia for cesarean delivery due to concerns for neonatal respiratory depression. However, clinicians should weigh that risk against the benefit of maternal hemodynamic control. In a meta-analysis of six randomized trials of elective cesarean delivery (one study in patients with preeclampsia), Apgar scores at one and five minutes were similar in patients who received remifentanil during induction and those who did not [65].
The neonatal resuscitation team should be notified of all medications administered to the mother during induction of general anesthesia.
Intraoperative magnesium — Magnesium sulfate is routinely administered in the intrapartum and postpartum period to patients with preeclampsia to prevent seizures, and should be continued in the operating room during cesarean delivery [30]. (See "Preeclampsia: Intrapartum and postpartum management and long-term prognosis", section on 'Seizure prophylaxis'.)
Magnesium causes muscle relaxation, potentiates the effect of nondepolarizing neuromuscular blocking agents (NMBAs), and can prolong the duration of action of rocuronium [67], cisatracurium [68], and vecuronium [69]. Since nondepolarizing NMBAs are rarely necessary during cesarean delivery, they should be avoided if possible for patients who are receiving magnesium. Magnesium does not potentiate the effects of succinylcholine, and the usual rapid sequence induction dose (ie, succinylcholine 1 to 1.5 mg/kg IV) should be administered.
When muscle relaxation is required, a small additional dose of succinylcholine (10 to 20 mg IV) or deeper anesthesia may be sufficient. If a longer duration of muscle relaxation is necessary, eg, to allow for better surgical conditions prior to or during fascial closure, small incremental doses of non-depolarizing NMBA (ie, rocuronium 10 to 20 mg IV or cisatracurium 2 to 4 mg IV) should be administered, and titrated to effect using a twitch monitor with the goal of one twitch in the train of four twitches. Quantitative or qualitative monitoring should also be used at the end of surgery to ensure adequate reversal of neuromuscular blockade.
Reversal of neuromuscular blockade, including appropriate choice and dose of reversal agents, is discussed in detail separately. (See "Clinical use of neuromuscular blocking agents in anesthesia", section on 'Reversal of neuromuscular block'.)
Postoperative pain control — Multimodal strategies for pain control are routinely used for all patients after cesarean delivery, including those with preeclampsia, to promote rapid recovery and ambulation and to minimize the need for postoperative opioids. Pain control strategies include neuraxial morphine or hydromorphone for patients who have neuraxial anesthesia, transverse abdominis plane blocks, quadratus lumborum blocks, acetaminophen, nonsteroidal antiinflammatory drugs (NSAIDs), and systemic opioids. (See "Anesthesia for cesarean delivery", section on 'Post-cesarean delivery analgesia'.)
We routinely administer NSAIDs (ketorolac 15 to 30 mg IV every six hours as needed, or ibuprofen 600 to 800 mg orally every six hours as needed) for 48 hours after cesarean delivery, and avoid NSAIDs for patients with significant blood loss during cesarean delivery, thrombocytopenia or other risk factors for bleeding.
NSAIDs are opioid sparing, and are especially effective for relief of uterine cramping, though these medications interfere with platelet function. (See "NSAIDs and acetaminophen: Effects on blood pressure and hypertension", section on 'Effect of NSAIDs on blood pressure'.)
A 2020 Practice Bulletin from the American Congress of Obstetricians and Gynecologists (ACOG) recommends the use of NSAIDS preferentially over opioids for postpartum pain in patients with hypertensive disorders, including preeclampsia [22]. Several studies of the use of NSAIDS in patients with preeclampsia have found no association between NSAIDs and postpartum blood pressure elevation or other adverse effects [70-72].
POSTPARTUM CARE — The risks for complications of preeclampsia continue into the postpartum period. These patients may remain hypertensive and are at risk for seizures, pulmonary edema, stroke, venous thromboembolism, and airway obstruction due to airway edema. (See "Preeclampsia: Intrapartum and postpartum management and long-term prognosis", section on 'Postpartum care'.)
For patients who undergo cesarean delivery, postoperative disposition (eg, post anesthesia recovery unit, intensive care unit) should be determined by the intraoperative course, patient factors, the need for ongoing invasive monitoring, and available resources.
ECLAMPSIA — Eclampsia refers to the occurrence of new-onset, generalized, tonic-clonic seizures or coma in a woman with preeclampsia. The precise etiology of seizures in eclampsia is not clearly understood, and may involve brain edema and/or ischemia. Obstetric management of eclampsia is discussed separately. (See "Eclampsia".)
Anesthesia clinicians may be called to manage the airway during an eclamptic seizure, or to provide anesthesia for vaginal or cesarean delivery [73]. Cesarean delivery should be delayed to allow maternal assessment and stabilization if a seizure occurs. Patients who do not improve promptly following control of hypertension and seizures and those who develop localizing neurologic signs should be evaluated by a neurologist for possible imaging to rule out stroke.
Seizures may rarely occur during cesarean delivery with neuraxial anesthesia. Treatment priorities in this setting are the same as the priorities for patients without anesthesia, as follows (see "Eclampsia", section on 'Prevention of recurrent seizures' and "Eclampsia", section on 'Management'):
●Airway protection and prevention of hypoxia — Supplemental oxygen should be provided and the airway supported until the seizure ends.
●Control of hypertension — Blood pressure control should be meticulously maintained at <160 mmHg systolic
●Prevention of recurrent seizures — Magnesium is the drug of choice for prevention of seizures. A loading dose of magnesium sulfate 4 to 6 g intravenous (IV) should be administered over 15 to 20 minutes, followed by 2 g per hour as a continuous infusion. (See "Eclampsia", section on 'Dosing and toxicity'.)
For recurrent seizures in patients already receiving magnesium, an additional dose of 2 g magnesium sulfate over 5 to 10 minutes should be administered, with frequent monitoring for signs of magnesium toxicity. If necessary, a seizure may be terminated with benzodiazepines, most commonly midazolam 1 to 2 mg IV, repeated every five minutes until the seizure stops. (See "Eclampsia", section on 'Prevention of recurrent seizures' and "Eclampsia", section on 'Management of recurrent seizures'.)
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: Hypertensive disorders of pregnancy" and "Society guideline links: Obstetric anesthesia".)
SUMMARY AND RECOMMENDATIONS
●Preanesthesia evaluation
•Anesthesia clinicians should evaluate patients with preeclampsia early in the peripartum period, with the expectation that emergency delivery may be required at any time. The evaluation should focus on the airway, hemodynamic status, and coagulation abnormalities. (See 'Preanesthesia evaluation' above.)
•Patients with preeclampsia are at risk for airway edema and difficulty with airway management. Airway edema may worsen during labor and delivery. (See 'Airway evaluation' above.)
•Thrombocytopenia and other coagulopathies may develop with severe preeclampsia, and may preclude neuraxial anesthesia techniques because of the risk of spinal epidural hematoma. We place epidural catheters early in labor, especially for patients with falling platelet counts. In the absence of other coagulopathies, we place epidural catheters for patients with a platelet count >70,000/microL, do not perform neuraxial techniques if the platelet count is ≤50,000/microL, and make individualized decisions for patients with a platelet count between 50,000 and 70,000/microL. (See 'Coagulation' above.)
●Intravenous fluid and blood pressure management
•Intravenous (IV) fluid administration should be restricted for patients with preeclampsia to avoid pulmonary edema. No fluid bolus is required for initiation of labor analgesia, and fluid co-loading with neuraxial anesthesia for cesarean delivery should be avoided or limited to <500 mL. (See 'Intravenous fluid management' above.)
•For patients with preeclampsia, we target a blood pressure at the patient's baseline, but always systolic <160 mmHg and diastolic <110 mmHg. (See 'Goal blood pressure' above.)
-Labetalol, hydralazine and nifedipine are reasonable choices for treatment of hypertension. (See 'Hemodynamic status' above and "Treatment of hypertension in pregnant and postpartum patients", section on 'Choice of therapy'.)
-Vasopressors should be administered in small doses (eg, ephedrine 2.5 to 5 mg IV, phenylephrine 25 to 50 mcg IV). (See 'Vasopressors during neuraxial analgesia' above.)
●Labor analgesia – We suggest the use of neuraxial analgesia for labor for patients with preeclampsia (Grade 2C). Continuous neuraxial analgesia attenuates the hypertensive response to labor pain and circulating catecholamines, and provides a means for rapid conversion to surgical neuraxial anesthesia and avoidance of general anesthesia. (See 'Advantages of neuraxial labor analgesia' above.)
●Anesthesia for cesarean delivery
•For patients with preeclampsia who undergo cesarean delivery, we recommend neuraxial anesthesia rather than general anesthesia (Grade 1B), primarily because it avoids the risk of severe, possibly life threatening hypertension during induction of anesthesia or during emergence. Endotracheal intubation may be difficult in these edematous patients. Spinal, epidural, and combined spinal-epidural may all be used safely. (See 'Choice of anesthetic technique' above.)
•For prevention of neuraxial anesthesia-induced hypotension for patients with preeclampsia, we administer a prophylactic, titrated administration of low-dose phenylephrine infusion (ie, starting at <50 mcg/min) with phenylephrine rescue boluses (eg, 25 to 50 mcg IV). For patients with bradycardia, ephedrine (5 to 10 mg IV bolus, or 1 to 5 mg/min IV infusion) should be administered as an alternative.
•When time permits, we consider placement of an arterial catheter prior to induction of general anesthesia for patients with severe preeclampsia. Induction of general anesthesia for these patients should always include steps to minimize or eliminate the hypertensive response to intubation. A variety of medications may be administered during induction for this purpose, with a target systolic blood pressure <160 mmHg (eg, labetalol, esmolol, nitroglycerin, nicardipine). (See 'Induction of anesthesia' above.)
●Magnesium therapy – Magnesium is routinely administered to prevent seizures in preeclamptic patients. We recommend continuing magnesium in the operating room during cesarean delivery (Grade 1A). Magnesium potentiates nondepolarizing neuromuscular blocking agents (NMBAs). If NMBAs are absolutely necessary, they should be administered in small, incremental doses, and the effect should be monitored with a peripheral nerve stimulator. (See 'Intraoperative magnesium' above.)
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