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Nonobstetric Surgery During Pregnancy

Brendan Carvalho, MBBCh, FRCA

An estimated 0.75%2% of pregnant women will un-dergo nonobstetric surgery during their pregnancy. Inthe United States, approximately 75,00080,000 partu-rients will be exposed to anesthesia and surgery eachyear, and these figures are likely to be underestimatedbecause pregnancy may be unrecognized at the time

of surgery. Positive pregnancy tests have been re-ported in 0.3%1.2% of females presenting for routinesurgery.

Surgery may be directly (e.g., cervical cerclage) orindirectly (e.g., ovarian cystectomy) related or unre-lated (e.g., appendicectomy, cholecystectomy) to thepregnancy and may be necessary during any stage ofpregnancy (Fig. 1).

Key Areas

Optimal anesthetic management of these pregnant pa-tients and their fetuses requires an understanding of:1. Normal alterations in maternal physiology during

pregnancy2. The potential fetal effects from anesthesia and

surgery3. Maintenance of uteroplacental perfusion and fetal

oxygenation4. Practical considerations (timing of surgery, fetal

monitoring, full stomach precautions, left uterine dis-placement, and other anesthetic considerations)

5. The importance of maternal counseling andreassurance

6. Special situations (laparoscopy, cardiopulmonary bypass, electroconvulsive therapy, neurosurgery andtrauma)

Maternal Physiology of Pregnancy

During pregnancy, increased hormonal concentra-tions, mechanical effects of the gravid uterus and in-creased metabolic demands result in significantchanges in maternal physiology.

Cardiovascular System

Pregnancy results in a progressive 30%50% increasein cardiac output above baseline by 2832 weeks ofgestation, resulting from increases in stroke volumeand heart rate (in the first half and the latter half of

pregnancy, respectively). The blood pressure usuallyfalls during pregnancy because of progesterone-induced vasodilatation and the low resistance placen-tal bed. The pulse pressure widens as a result of agreater reduction in diastolic compared with systolicblood pressure.

Supine Hypotension

During the second half of gestation, the weight of theuterus compressing the inferior vena cava decreasesvenous return and cardiac output by approximately25%30% when the mother lies supine. Although up-per extremity blood pressure may be maintained by

compensatory vasoconstriction and tachycardia,uteroplacental perfusion is significantly reduced. Toavoid or minimize supine hypotension, it is essentialto displace the uterus laterally during any operationperformed after 20 weeks of pregnancy.

Hematological System

The plasma volume increases by 40%50% from pre-pregnancy levels. This raised plasma volume exceedsthe increase in red blood cells, resulting in a relativedilutional anemia. This may compromise oxygen de-livery and decrease the patients reserve if significanthemorrhage occurs. Pregnancy is associated with a

benign leukocytosis, which makes the white blood cellcount an unreliable indicator of infection. Pregnantpatients requiring surgery are at high risk for periop-erative thromboembolic complications because ofpregnancy-related increases in coagulation factors (fi-brinogen, factors VII, VIII, X, and XII).

Respiratory System

Alveolar ventilation increases throughout pregnancy to45%70% above pre-pregnancy levels by term. This re-sults in hypocarbia (Paco2 2732 mm Hg) and respira-

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Table of Contents
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tory alkalosis (pH of 7.47.45). Pregnant women have areduced oxygen reserve as a result of increased oxygenconsumption and lower functional residual capacity(FRC). This results in rapid development of hypoxemiaand acidosis during periods of hypoventilation or apnea.Anatomical changes and weight gain during pregnancy

as well as capillary engorgement of the respiratory tractmucosa lead to more frequent difficult mask ventilationand failed endotracheal intubation.

Gastrointestinal and Renal System

Pregnant women are at risk for esophageal reflux,regurgitation of gastric contents, and aspiration pneu-monitis from lower esophageal sphincter incompe-tence, distortion of gastric and pyloric anatomy, andincreased gastric pressure from the gravid uterus. Al-though it is unclear at what stage during pregnancythis risk becomes significant, gastric aspiration pro-

phylaxis should be considered after 1620 weeks ges-tation. Renal blood flow and glomerular filtrationrates increase significantly during pregnancy. Thiscauses creatinine and blood urea nitrogen levels todecrease and normal laboratory values should be ad- justed accordingly for pregnant patients.

Central Nervous System and Response toAnesthesia

General Anesthesia. Induction of anesthesia occursmore rapidly during pregnancy because alveolar hy-perventilation and decreased FRC allow faster equili-

bration of inhaled agents. Minimum alveolar concen-tration for volatile anesthetic agents decreases byapproximately 30%40% in pregnancy, and subanes-thetic concentrations of anesthetic agents can induceunconsciousness.

Regional Anesthesia. More extensive neural block-ade is usually obtained after neuraxial anesthesia,possibly as a result of a decreased epidural spacecapacity and an enhanced response to neural blockadeas a result of hormonal changes in pregnancy.

Fetal Concerns

Risk of Teratogenicity

Despite theoretical concerns, no anesthetic agentshave been conclusively shown to be tetratogenic in

humans. However, because of the rarity of congenitaldefects and ethical issues, definitive prospective clin-ical studies investigating possible teratogenic effects ofanesthetic agents are impractical. Extrapolation offindings from animal studies to drug effects duringanesthesia in humans (single dose, limited exposure)are limited because of potential species-specific ef-fects, experimental design issues (e.g., poor control ofblood pressure and oxygenation during anesthesia),and the use of higher doses for prolonged periods.Epidemiologic surveys of operating room personnelchronically exposed to subanesthetic concentrations ofinhalation agents and outcome studies of pregnant

women who have undergone surgery have not defin-itively demonstrated increases in teratogenicity. Al-though there are no anesthetic agents proven to beteratogens, ideally, pregnant patients should be ex-posed to the fewest drugs possible and at the lowestconcentration clinically indicated. Organs have differ-ent periods of sensitivity and vulnerability. Drug ex-posure during the period of organogenesis (approxi-mately Days 1570 after the first day of the lastmenstrual period) is best avoided if possible. In addi-tion, other factors during anesthesia and surgery (hyp-oxia, hypercapnia, stress, temperature, ionizing radi-ation 510 rads) may be teratogenic themselves or

enhance the teratogenicity of other agents. Anesthetic Agents and Perioperative Medication. Tera-

togenesis has not been associated with the use of anycommonly used induction agents, including barbitu-rates, ketamine, and propofol. Despite concerns aboutpotential teratogenic effects from chronic diazepamtherapy during pregnancy, there is no evidence tosuggest that a single dose of a benzodiazepine (e.g.,midazolam) during the course of anesthesia would beharmful to the fetus. Similarly, no evidence supportsthe teratogenicity of opioids and muscle relaxants inhumans. Muscle relaxants appear to have a wide mar-gin of safety because of limited placental transfer.

There is also no evidence to support teratogenicity oflocal anesthetic in humans. Under well-controlledconditions, no teratogenic effects have been associatedwith any volatile agents in clinical concentrations.

Nitrous Oxide. Under certain conditions, nitrousoxide is a weak teratogen in rodents (e.g., at 50%concentrations for 24 h). Proposed etiologies for ni-trous oxide teratogenicity include methionine syn-thase inhibition, which alters DNA synthesis, or in-duced sympathetic and/or 1-adrenergic receptor

Figure 1. Trimester breakdown of nonobstetric surgery undertakenduring pregnancy. Modified from Mazze RI, Kallen B. Am J ObstetGynecol 1989;161:1178 85.

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stimulation. However, epidemiologic and outcomedata in humans do not support an increased risk ofcongenital anomalies with nitrous oxide exposure.

Preterm Labor

Most epidemiologic studies of nonobstetric surgeryduring pregnancy have reported an increased inci-dence of preterm delivery. It is unclear whether sur-gery, manipulation of the uterus, or the underlyingsurgical pathology is responsible. Second trimesterprocedures and those that do not involve uterine ma-nipulation carry the lowest risk for preterm labor.Surgical strategies to minimize handling of the uterusshould be considered. Volatile anesthetic agents de-press myometrial irritability and are potentially ad-vantageous for abdominal or high-risk procedures.Beta-2 agonists (e.g., terbutaline) and magnesium areeffective tocolytics, although their routine prophylac-tic use is controversial because of their potential risksand limited benefits on preterm labor prevention. Se-lective tocolytic administration to patients at greatestrisk (e.g., cervical cerclage) can be considered. Indo-methacin is used to prevent premature onset of labor;however, the potential risks (e.g., premature closure ofductus arteriosus and development of oligohydram-nios) should be considered. Nitroglycerin can be usedfor uterine relaxation during short procedures or tomanage refractory uterine activity. When technically fea-sible, external tocodynamometer monitoring for uterinecontractions should be performed intraoperatively. Pa-tients who receive potent analgesics and who may beunaware of mild uterine contractions should receive fe-tal monitoring during the postoperative period.

Other Potential Fetal Risks

Some outcome studies show an increased risk of spon-taneous abortions and low birth weight (LBW) infantsin patients who underwent surgery during pregnancy.LBW results from both preterm delivery and intrauter-ine growth restriction. Relative risk of spontaneous abor-tion among women who had general anesthesia for sur-gery during pregnancy for nongynecological andgynecological surgery is 1.6 and 2.0, respectively. Al-

though anesthesia and surgery are associated with anincreased incidence of spontaneous abortion, IUGR, andperinatal mortality, these can be attributed to the proce-dure, surgical site, and/or the underlying maternal con-dition not necessarily exposure to anesthesia.

Behavioral Effects

Recent evidence suggests that some anesthetic, anal-gesic, and psychoactive drugs may induce widespreadneuronal apoptosis in the developing rat brain whenadministered for prolonged periods during the periodof synaptogenesis or brain growth spurt. These changes

may produce behavioral deficits and persist into adoles-cence and adulthood, affecting behavior and function.However, behavioral teratology has not been demon-strated in humans and its significance is yet to bedetermined.

Uteroplacental Perfusion and Fetal

OxygenationFetal oxygenation depends on maternal oxygen deliv-ery (arterial oxygen tension and oxygen-carrying ca-pacity) and uteroplacental perfusion. Transient andmoderate decreases in maternal Pao2 are well toler-ated by the fetus because fetal hemoglobin is presentin high concentration and has a high affinity for oxy-gen. However severe prolonged maternal hypoxemiamay cause fetal hypoxia and fetal death. Any compli-

cation that causes profound maternal hypoxemia (e.g.,difficult intubation, pulmonary aspiration, high spi-nal) is a potential threat to the fetus. In contrast, mod-erate hyperoxia improves fetal oxygenation and is notassociated with intrauterine retrolental fibroplasia andpremature ductus arteriosus closure because of thelarge maternal-fetal oxygen tension gradient. Paco2should be kept in the normal range for pregnancy.Maternal hypercapnia can cause fetal acidosis thatmay result in fetal myocardial depression and hypo-tension. Maternal hyperventilation and hypocarbiacan compromise maternal-fetal oxygen transfer bycausing umbilical artery constriction and shifting the

maternal oxyhemoglobin dissociation curve to the left.Maternal hypotension from any cause can jeopardizeuteroplacental perfusion and cause fetal asphyxia.Provided that hypotension is prevented, maternal ad-ministration of volatile agents in moderate concentra-tions (11.5 MAC) has minimal effect on uteroplacen-tal blood flow. Uteroplacental perfusion may bereduced by uterine vasoconstriction from drugs suchas high dose -adrenergics or increased circulatingcatecholamines (e.g., preoperative anxiety and lightanesthesia). Drugs that cause uterine hypertonus (e.g.,ketamine in early pregnancy in doses 2 mg/kg or-adrenergics) may also compromise uteroplacental

perfusion.

Practical Anesthetic Considerations

Timing of Surgery

As a general rule, elective surgery should not be per-formed during pregnancy. If surgery is necessary (car-diac, neurosurgery, abdominal emergencies, or malig-nancies), choice of timing is essentially a balancebetween maternal and fetal risks and the urgency ofsurgery (Fig. 2).

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For the fetus, the second trimester is the optimal

time to perform surgery. The theoretical risk of terato-genicity is increased during the period of organogen-esis in the first trimester and the risk of preterm laboris higher during the third trimester. Maternal risk isgreatest during the third trimester because of physio-logical changes of pregnancy. However, the primarygoal is to preserve the mothers life, and remote fetalrisks associated with anesthesia and surgery are ofsecondary importance in the event of a serious mater-nal illness. When planning surgery, it is important toensure that her obstetrician is informed and that con-tingency plans have been discussed in the event ofcomplications. The decision to perform simultaneous

cesarean delivery depends on a number of factors e.g.,gestational age and maternal condition. Cesarean de-livery may be performed immediately before the sur-gical procedure to avoid fetal risks associated withprolonged anesthesia and intraoperative cardiopul-monary changes and blood loss.

Diagnosis

Because of diagnostic difficulties, the disease (espe-cially intra-abdominal pathology such as appendicitis)may be advanced at the time of surgery. Nausea,vomiting, constipation, and distention are commonsymptoms of both normal pregnancy and abdominal

pathology. Further diagnostic uncertainty is intro-duced by the increased white blood cell count, whichcan reach 15,000/mm3 in normal pregnancy. Furtherdelay may result from the reluctance to perform nec-essary studies involving radiation on pregnantpatients.

Fetal Monitoring During Surgery

Intermittent or continuous fetal heart rate (FHR) mon-itoring should be considered for the viable-age fetusand for major surgical procedures. It should be con-sidered a tool to monitor intrauterine well-being, not

to avoid medicolegal claims. Continuous transabdom-inal FHR monitoring is feasible from 1822 weeksgestation. Transabdominal monitoring may not bepossible during abdominal procedures or when themother is very obese. A vaginal Doppler probe may be

considered in selected cases. Fetal well-being, as indi-cated by FHR variability, is present by 2527 weeksgestation. Loss of beat-to-beat variability and de-creased baseline FHR are common after administra-tion of anesthetic agents but decelerations suggestfetal hypoxemia. An unexplained change in FHR man-dates the evaluation of maternal position, blood pres-sure, oxygenation, acid-base status, and inspection ofthe surgical site to ensure that neither surgeons norretractors are impairing uterine perfusion. Maternalhypothermia during surgery may result in slowing ofthe fetal heart rate. Monitoring maternal temperatureperioperatively and the use of warming devices to

maintain normothermia are important. IntraoperativeFHR monitoring requires the presence of a trainedpractitioner to monitor and interpret the tracing. Amultidisciplinary plan is necessary in the event ofpersistent fetal distress, e.g., performing an emergencycesarean delivery.

Anesthetic Management

Preoperative Care. Gastric aspiration prophylaxis(H2-receptor antagonist and 30 mL of a nonparticulateantacid before the induction) should be consideredafter 1620 weeks gestation. Premedication anxiolysis(e.g., midazolam 1 mg) may be necessary for the anx-

ious parturient, as elevated catecholamines may de-crease uterine blood flow.

Prevention of Aortocaval Compression. After 20 weeksgestation, the pregnant patient should be transportedin the lateral position, and left uterine displacementinstituted when positioned on the operating table. Theeffectiveness of left uterine displacement can be as-sessed by measuring the blood pressure on the rightleg or observing the pulse oximeter waveform on theright foot. For surgery in the prone position, the ab-domen should hang unobstructed and any externalcompression should be avoided.

Anesthetic TechniqueNo study has correlated improved fetal outcome withany anesthetic technique and the choice of anesthesiashould be guided by maternal indications as well asthe site and nature of the surgery. When possible, alocal or regional anesthetic technique may be prefera-ble. Regional techniques minimize fetal drug exposureand maternal perioperative complications. However,laparoscopy and most upper abdomen operationsusually require general anesthesia. Regardless of thetechnique used, avoidance of hypoxemia, hypoten-sion, hypovolemia, acidosis, and hypercarbia/

Figure 2. Timing of nonobstetric surgery in a pregnant surgicalpatient. Adapted from Rosen MA. Anesthesiology 1999;91:115963.


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hypocarbia are the most critical elements of the anes-thetic management. Blood glucose levels should be checked, especially during prolonged surgery orin patients with gestational diabetes or glucoseintolerance.

General Anesthesia

Induction. General anesthesia mandates endotra-cheal intubation beginning at approximately 1620weeks gestation. Preoxygenation with 100% oxygenadministration for 34 min (or 4 vital capacity breathsif time is restricted) before a rapid sequence inductionwith cricoid pressure should be performed. Fascicula-tion after the administration of succinylcholine doesnot occur consistently. The use of a smaller endotra-cheal tube (6.07.0 mm) is recommended because of

respiratory tract mucosa edema and engorgement as-sociated with pregnancy. Avoid nasal intubations thatmay precipitate bleeding because of increased muco-sal vascularity. Use drugs with a history of safe useduring pregnancy including thiopental, morphine, fent-anyl, succinylcholine, and most nondepolarizing musclerelaxants. Although not similarly time-tested, manyconsider propofol safe during pregnancy.

Maintenance. A moderate concentration of a vola-tile agent (1.52.0 MAC) with a high concentration ofoxygen (Fio2 0.5) is recommended. Although scien-tific evidence does not support avoidance of nitrousoxide during pregnancy, using concentrations of

50% and limiting its use in the first trimester andduring extremely long operations is suggested. If ni-trous oxide is avoided, adequate analgesia should beadministered to minimize the need for higher doses ofa volatile agent that may cause maternal hypotension.Opioids and induction agents decrease FHR variabil-ity to a greater extent than do the inhalation agents.Opioid-induced fetal respiratory depression is rele-vant only if cesarean delivery is to be performed at thesame time as the surgical procedure.

Positive-pressure ventilation may reduce uterineblood flow and decrease uteroplacental perfusion as a

result of increased intrathoracic pressure and de-creased venous return. Hyperventilation should beavoided and end-tidal CO2 should be maintained inthe normal range for pregnancy. Plasma cholinester-ase levels decrease by approximately 25% in preg-nancy; however, prolonged neuromuscular blockadewith succinylcholine is uncommon because concomi-tant larger volumes of distribution associated withpregnancy offsets the impact of decreased drug hy-drolysis. The pharmacokinetic and pharmacodynamicprofiles of many drug administered to pregnant pa-tients may differ from nonpregnant patients. Patients

on magnesium for tocolysis may have prolonged mus-cle paralysis after the administration of muscle relax-ants; therefore, reducing the dose of muscle relaxant isrecommended.

The effects of reversal agents are unpredictable. Be-

cause of theoretical concerns of anticholinesteraseagents increasing uterine tone and precipitating pre-term labor, slow administration after a preceding doseof atropine is recommended. Glycopyrrolate is oftenrecommended because it crosses the placenta lessreadily than does atropine. Atropine rapidly crossesthe placenta and in large doses may cause fetal tachy-cardia and loss of FHR variability. However, transpla-cental passage of atropine may be preferable to coun-teract the fetal effects of neostigmine. Althoughlimited anticholinesterase transplacental transfer ispredicted because of its molecular size and structure,

neostigmine can have significant transplacental pas-sage and fetal effects without concomitant atropineadministration.

Regional Anesthesia

Maternal hypotension associated with spinal or epi-dural anesthesia should be prevented or minimized byfluid preloading and leg compression devices. Appro-priate vasopressors should be available to treat hypo-tension if it occurs. Phenylephrine has been shown tobe the preferred vasopressor for the treatment of hy-potension after neuraxial anesthesia for cesarean de-

livery, as the use of ephedrine causes greater fetalacidosis. Patients receiving magnesium are moreprone to hypotension, which is often more resistant totreatment with vasopressors. Pregnant patients mayhave reduced requirements for local anesthetics andappropriate dose reduction is necessary to prevent ahigh block. Patients are at higher risk for systemiclocal anesthetic toxicity because decreased proteinbinding during pregnancy results in a greater fractionof unbound drug.

Postoperative Care

The FHR and uterine activity should be monitoredduring recovery from anesthesia. If the fetus is viableand premature labor occurs, early pediatric consulta-tion is advised and, if necessary, the patient should betransferred to a hospital with a neonatal intensive careunit. Adequate analgesia should be obtained with sys-temic or spinal opioids. Regional anesthesia may bepreferable because systemic opioids may reduce FHRvariability. The routine and prolonged use of nonste-roidal antiinflammatory drugs is best avoided becauseof potential fetal effects (e.g., premature closure of


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ductus arteriosus and development of oligohydram-nios). Acetaminophen is safe to prescribe in this set-ting. Early mobilization and venous thrombosis pro-phylaxis should be considered as patients are at riskfor thromboembolism.

Counseling and ReassuranceA pregnant patient requiring surgery will naturally beextremely nervous and anxious. In addition to thestress of having to undergo a surgical procedure, shewill have many justifiable concerns about the potentialeffects of anesthesia on her unborn child. There is a lotof misinformation about the potential risks that maycompound her anxiety. Concerns regarding congenitalmalformations, fetal loss, and the risk of prematureonset of labor should all be addressed. The patientshould be reassured about the safety of anesthesia andthe lack of documented associated teratogenicity. Pa-tients should be warned about the increased risk of

first trimester miscarriages and premature delivery(approximately 5% without surgery to 6%8% withsurgery). It is important to document details of therisks discussed in the patients records. In addition, itis advisable to educate the patient about symptoms ofpremature labor and to reinforce the need for leftuterine displacement in the perioperative and postop-erative periods. If the patient is awake during theprocedure, FHR monitoring during surgery is reassur-ing and can be offered.

Special SituationsLaparoscopy

Laparoscopy may be performed during pregnancy forboth diagnostic and therapeutic surgery (e.g., chole-cystectomy, appendectomy, ovarian torsion). Once re-garded as contraindicated in pregnancy, in recentyears laparoscopy is being performed with increasingfrequency because of its many benefits (e.g., shorterhospitalization, less postoperative pain) over conven-tional surgery. Studies comparing laparotomy withlaparoscopy report no differences in fetal outcome. Toensure laparoscopy during pregnancy is undertaken

safely, it is important to consider key differences com-pared to nonpregnant patients (Table 1).

General anesthesia has been used for the majority oflaparoscopy procedures, although there are severalreports describing the use of epidural anesthesia. Thepneumoperitoneum and Trendelenburg position mayreduce lung compliance and FRC, increase airwaypressures, and predispose to hypoxemia, especiallywith advanced gestation. The combination of pneu-moperitoneum, aortocaval compression, and the re-verse Trendelenburg position can result in significantdecreases in venous return and hypotension. Limitingthe insufflation pressure, left uterine displacementand limited reverse Trendelenburg initiated slowlywill minimize decreases in blood pressure. Vasopres-sors (e.g., ephedrine, phenylephrine) may be neededto treat hypotension and maintain maternal bloodpressure during laparoscopy. Fetal well-being is bestpreserved by maintaining maternal oxygenation, acid- base status, and hemodynamic measurements withinnormal pregnant limits. FHR and uterine tone moni-toring may not be possible during peritoneal insuffla-tion except by the transvaginal route. The prothrom- botic pregnancy state and lower extremity venousstasis from the pneumoperitoneum increase the risk ofthromboembolism. Intermittent pneumatic compres-sion devices and thromboembolic prophylaxis areimportant.

Cardiopulmonary Bypass During Pregnancy

Cardiopulmonary bypass (CPB) may be necessaryduring pregnancy for open valve surgery and to man-

age aortic dissection, massive pulmonary or amnioticfluid embolus, and coronary artery dissection. If pos-sible, surgery requiring CPB should be delayed untilthe second trimester or later. Most cardiac operationswith CPB during pregnancy can be performed withreasonable safety in the mother, but there is increasedrisk for the fetus. If the parturient tolerates pregnancy,a primary cesarean delivery with concomitant orstaged CPB with surgical repair can be performed.Patients requiring CPB should be managed in a ter-tiary center with multidisciplinary team involvement.Important considerations in the pregnant patient un-dergoing CPB are outlined in Table 2.

Table 1. Laparoscopy During Pregnancy

Use an open technique to enter the abdomen to avoid potential uterine or fetal trauma Monitor maternal end-tidal CO2 (3035 mmHg range) arterial blood gas (if the procedure is prolonged) to

avoid fetal hypercarbia and acidosis Maintain low pneumoperitoneum pressures (812 mm Hg, not 15 mm Hg) and minimize insufflation time or

use a gasless technique to avoid decreases in uteroplacental perfusion Protect the uterus with lead shielding during periods of radiation Limit the extent of Trendelenburg and reverse Trendelenburg positions and initiate any position changes slowly Monitor fetal heart rate and uterine tone when feasible


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Electroconvulsive Shock Therapy

The treatment of major psychiatric disorders duringpregnancy is problematic and optimal managementremains controversial. Electroconvulsive shock ther-apy (ECT) avoids potential teratogenicity from psych-otropic medications and it is often used to treat majordepression and bipolar disorders during pregnancyespecially when rapid control of depressive symptomsis needed. ECT does not appear to be a significant riskfactor for miscarriage, stillbirths, or premature labor.Key points to consider are outlined in Table 3.

Cardioversion During Pregnancy

Maternal cardiac arrhythmias are not uncommon dur-ing pregnancy and may jeopardize the life of themother and the fetus. The management of arrhythmiasduring pregnancy is similar to that for nonpregnantpatients. When antiarrhythmic drug treatments fail orare not indicated because of hemodynamic instability,direct current cardioversion should be attempted. Car-dioversion has been performed safely during preg-nancy. Although it is a relatively low-risk procedure,FHR monitoring and plans to perform emergency ce-sarean delivery in the event of fetal distress should beconsidered. Key management points are similar toECT and are outlined in Table 3.

Neurosurgery During Pregnancy

Neurosurgical interventions (e.g., aneurysm or arte-riovenous malformation repair) may be necessaryduring pregnancy. Because the placental bed is unableto autoregulate and requires adequate perfusion pres-sures, controlled or induced hypotension will reduceuteroplacental perfusion. A 25%30% reduction insystolic BP or a mean BP 70 mm Hg may lead to areduction in uteroplacental blood flow. Limiting thedose (0.5 mg kg1 h1) and duration of sodiumnitroprusside administration is important as it can

accumulate in the fetus and cause cyanide toxicity.Nitroglycerin may be a safer alternative. Excessivematernal hyperventilation and hypocarbia (25 mmHg) can compromise maternal-fetal oxygen transfer.

FHR monitoring should be performed continuously,especially if induced hypotension and hyperventila-tion is planned so that necessary adjustments can bemade if fetal distress occurs. Osmotically active agents(e.g., mannitol, loop diuretics) can cause significantfluid shifts in the fetus. Hypovolemia and very largedoses of mannitol should be avoided as they have thepotential to cause fetal dehydration. If endovasculartreatments are undertaken, then uterine shielding dur-ing periods of radiation is necessary.

Trauma During Pregnancy

Trauma is one of the leading nonobstetric causes ofmorbidity and mortality. The primary managementgoals (airway maintenance and resuscitation) are sim-ilar to the care of nonpregnant trauma cases. Avoid-ance of hypoxia, hypotension, acidosis and hypother-mia are important for maintenance of uteroplacentalperfusion and fetal well-being. Pregnant patients aremore prone to developing pulmonary edema resultingfrom relative hypoproteinemia and hypervolemia. Instable patients without ongoing blood loss, conserva-tive fluid management is preferable and central ve-nous monitoring should be consider if renal insuffi-ciency or fluid overload occurs. Trauma may result in

Table 2. Cardiopulmonary Bypass During Pregnancy

Maintain high pump flows (3050% increase over the non-pregnant state) Maintain mean arterial/perfusion pressures 60 mmHg for optimal uteroplacental perfusion Limit hypothermia (temperatures 32C can reduce uteroplacental perfusion and cause fetal dysrhythmias and

cardiac arrest)

Monitor fetal heart rates continuously during CPB Optimize acid-base, glucose, Pao2 and Paco2

Table 3. ECT During Pregnancy

Use anesthetic agents (e.g. barbiturates, succinylcholine, anticholinergics) with a long history of safe use duringpregnancy

Confirm the absence of uterine contractions using tocodynamometry before and after ECT Monitor the FHR immediately before and after ECT Consider full stomach prophylaxis and endotracheal intubation after the first trimester Provide left uterine displacement in patients 20 weeks gestation

Table 4. Indications for an Emergency Cesarean Delivery

in a Pregnant Trauma Patient

1. Traumatic uterine rupture2. Stable mother with viable fetus that is in distress3. A unsalvageable mother who still has a viable

fetus4. A gravid uterus that is interfering with

intraoperative surgical repair


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placental abruption and fetal loss. The primary aimshould be optimization of the mother, and the obstet-ric management can be planned at a later point. Afterinitial resuscitation and trauma surveys are complete,an early ultrasound in the emergency room is recom-

mended to determine fetal viability. Indications for anemergency or urgent cesarean delivery are outlined inTable 4. No radiological or invasive tests should bewithheld because of fetal concerns. Whenever possible, the uterus should be shielded during radiationprocedures. Ultrasound and magnetic resonance im-aging that do not utilize ionizing radiation arepreferable.

Further ReadingACOG Educational Bulletin. Teratology. Number 236, April 1997.

American College of Obstetricians and Gynecologists. Int JGynaecol Obstet 1997;57:31926.

ACOG Committee Opinion. Number 299, September 2004. Guide-lines for diagnostic imaging during pregnancy. Obstet Gynecol2004;104:64751.

ACOG Committee Opinion. Number 284, August 2003: Nonobstet-ric surgery in pregnancy. Obstet Gynecol 2003;102:431.

Anand KJ, Soriano SG. Anesthetic agents and the immature brain:are these toxic or therapeutic? Anesthesiology 2004;101:52730.

Cohen-Kerem R, Railton C, Oren D, et al. Pregnancy outcome fol-lowing non-obstetric surgical intervention. Am J Surg 2005;190:46773.

Goodman S. Anesthesia for nonobstetric surgery in the pregnantpatient. Semin Perinatol 2002;26:136 45.

Guidelines for laparoscopic surgery during pregnancy. Society ofAmerican Gastrointestinal Endoscopic Surgeons (SAGES). SurgEndosc 1998;12:18990.

Kuczkowski KM. Nonobstetric surgery during pregnancy: what arethe risks of anesthesia? Obstet Gynecol Surv 2004;59:526.

Levinson G. Anesthesia for surgery during pregnancy. In: HughesSC, Levinson G, Rosen MA, eds. Shnider and Levinsons Anes-thesia for obstetrics. 4th ed. Philadelphia: Lippincott Williams &Wilkins, 2001:249 65.

Mattox KL, Goetzl L. Trauma in pregnancy. Crit Care Med 2005;33:S3859.

Mazze RI, Kallen B. Reproductive outcome after anesthesia andoperation during pregnancy: a registry study of 5405 cases. Am JObstet Gynecol 1989;161:1178 85.

Melnick DM, Wahl WL, Dalton VK. Management of general surgicalproblems in the pregnant patient. Am J Surg 2004;187:17080.

Naughton NN, Cohen SE. Non-obstetric Surgery During Pregnancy.In: Chestnut D, ed. Obstetric anesthesia: principles and practice.3rd ed. St. Louis: Mosby, 2004:25572.

Olney JW, Young C, Wozniak DF, et al. Anesthesia-induced devel-opmental neuroapoptosis: does it happen in humans? Anesthesi-ology 2004;101:2735.

Parry AJ, Westaby S. Cardiopulmonary bypass during pregnancy.

Ann Thorac Surg 1996;61:18659.Rosen MA. Management of anesthesia for the pregnant surgical

patient. Anesthesiology 1999;91:115963.Shay DC, Bhavani-Shankar K, Datta S. Laparoscopic surgery during

pregnancy. Anesthesiol Clin North America 2001;19:5767.Steinbrook RA. Anaesthesia, minimally invasive surgery and preg-

nancy. Best Pract Res Clin Anaesthesiol 2002;16:13143.Weinberg L, Steele RG, Pugh R, et al. The pregnant trauma patient.

Anaesth Intensive Care 2005;33:16780.Weiss BM, von Segesser LK, Alon E, et al. Outcome of cardiovas-

cular surgery and pregnancy: a systematic review of the period19841996. Am J Obstet Gynecol 1998;179:164353.


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