Management of Common Surgical Conditions During Pregnancy



Management of Common Surgical Conditions During Pregnancy


Gianna Wilkie

Julianna Schantz-Dunn



OVERVIEW

Nonobstetric surgery during pregnancy is challenging for clinicians who care for reproductive-aged women due to concerns for teratogenicity, pregnancy loss, and preterm birth. Surgical procedures unrelated to pregnancy are rare but sometimes necessary. In a series of 720,000 women, the incidence of nonobstetric surgery was 0.75%.1 Given the inability to study this population in randomized controlled trials, specific recommendations on the management of pregnant patients with surgical conditions come from the review of case series and expert opinion. The most common surgical conditions encountered during pregnancy are appendicitis, gallbladder disease, bowel obstruction, adnexal torsion, hernias, and trauma.


GENERAL SURGICAL CONSIDERATIONS DURING PREGNANCY

There are risks associated with surgery in pregnancy that make providers hesitant to operate on patients, resulting in significant debate on the optimal approach to surgical conditions. There are, however, a few considerations that are universal to the management of patients requiring nonobstetric surgery in pregnancy. These include preoperative consultation with an obstetrician, positioning, surgical timing, surgical approach, thromboprophylaxis, choice of antibiotic prophylaxis, antenatal corticosteroid use, and tocolytic administration.


Obstetric Consultation

Consultation with an obstetrician or maternal fetal medicine specialist should be obtained prior to performing surgery or an invasive procedure. An obstetrician can provide recommendations regarding the need for fetal heart monitoring. Depending on the gestational age of the pregnancy, confirmation of the fetal heart beat before and after the surgery may be sufficient for fetal testing, while other times continuous fetal monitoring intraoperatively may be required if the patient is at a more advanced gestational age. Fetal heart rate monitoring assists in optimizing maternal position, cardiorespiratory management, and influences the decision to deliver a fetus.2 In general, continuous fetal monitoring is reserved for fetuses greater than 23 and 5/7 weeks gestation.



Surgical Positioning

Maternal positioning is a critical part of surgical preparation both peri- and intraoperatively. A left lateral tilt when in the supine position is optimal to keep the gravid uterus elevated off the inferior vena cava to assist both the maternal and fetal circulation.3 This positioning is recommended for all women greater than 20 weeks gestational age.


Timing of Surgery

Elective surgery should be postponed until after delivery as the risks associated with surgery and anesthesia should be avoided. However, a pregnant woman should never be denied urgent indicated surgery, regardless of the trimester.2 Surgical delay or nonintervention with conservative management can lead to increased morbidity for the woman and a negative impact on the fetus. Nonurgent surgery is performed in the second trimester when preterm contractions and spontaneous abortion are least likely.2 As miscarriage commonly occurs in the first trimester, surgery and anesthesia performed in the first trimester may be the attributed cause of spontaneous abortion while chromosomal or structural anomalies of the fetus may be the true underlying cause. It is crucial to minimize exposure of the fetus to surgery and medication during pregnancy, especially during organogenesis in the first trimester, given the associated increased risk of spontaneous abortion.4 Anesthetic agents can be used as they have no known teratogenic effects.5


Surgical Approach

The approach to various surgeries is also critical to consider, as a standard laparoscopic approach may not always be suitable for common surgical conditions such as appendicitis or cholecystitis. The size of the gravid uterus may impact the ability to enter the abdomen laparoscopically in a standard fashion or impair the ability to see structures in the lower abdomen and pelvis. However, laparoscopy appears to be associated with shorter operative times, shorter length of stay, and fewer complications in comparison to laparotomy.6 There are concerns that increased intra-abdominal pressure with laparoscopy may lead to decreased uterine blood flow and increased intrauterine pressure, resulting in fetal hypoxia.7,8 There is a risk of uterine and fetal injury with placement of the Veress needle and primary trocar entry, especially in the third trimester.6 These injuries can be significantly reduced by using an open technique to insert the initial trocar.


Thromboprophylaxis

Pregnancy is a well-known prothrombotic state and surgery is an additional risk factor for thrombosis. Pneumatic compression devices should be placed on all pregnant women undergoing surgery. The need for pharmacologic prophylaxis should be determined on a case-by-case basis, weighing in other risk factors in addition to pregnancy for thromboembolism including thrombophilia, prolonged immobilization, past history of venous thrombosis, malignancy, diabetes mellitus, varicose veins, paralysis, and obesity.9


Antibiotic Prophylaxis

Antibiotic prophylaxis should be given if indicated for a specific procedure, as pregnancy in itself is not an indication for antibiotics. Caution is given to the teratogenicity of some antibiotics. For example, fluoroquinolones and tetracyclines are generally avoided in pregnancy.10 Antibiotics such as beta-lactams, vancomycin, metronidazole, clindamycin, nitrofurantoin, and fosfomycin are generally considered safe and effective in pregnancy.10


Antenatal Glucocorticoid Use

Prophylactic glucocorticoids should be discussed prior to any surgery given the increased risk of preterm labor and delivery. Administration of a course of antenatal glucocorticoids 24 to 48 hours prior to surgery in patients between 24 and 34 weeks gestation can reduce perinatal morbidity and mortality if preterm birth occurs.11 This decision depends upon the urgency of the surgery and the obstetrician’s estimate of whether the patient is at increased risk of preterm birth because of the underlying disease or the planned procedure. Some will advocate for administration of antenatal glucocorticoids between 34 and 0/7 weeks and 36 and 6/7 weeks of gestation for those mothers who are at risk of preterm birth within 7 days and have not previously received steroids.11



Tocolytic Administration

Tocolytics are indicated for the treatment of preterm labor until resolution of the underlying, self-limited condition that may have caused the contractions. However, prophylactic administration of perioperative tocolytics does not have any beneficial effect.12 Indomethacin is often used postoperatively to reduce the risk that inflammation from surgery (or the underlying condition leading to surgery) may cause preterm labor. Indomethacin should not be used after 32 weeks of gestation given the risk of fetal ductus arteriosus closure.13


IMAGING TECHNIQUES IN PREGNANCY

The use of diagnostic imaging is critical in the diagnosis of many surgical conditions including bowel obstructions, cholecystitis, and appendicitis. Apprehension regarding the safety of imaging and radiation exposure in pregnancy has led to delays in diagnosis due to avoidance of imaging studies.14 Ultrasonography and magnetic resonance imaging (MRI) are the preferred imaging techniques for the pregnant patient as they are not associated with fetal risks (Table 7.1).14 However,
plain radiography, computed tomography (CT) scan, or nuclear medicine imaging techniques should be offered to patients if medically necessary as the radiation exposure with these techniques is lower than the dose associated with fetal harm.14 The best imaging study for the suspected clinical diagnosis should be done for pregnant patients in order to avoid delays in diagnosis that result in increased maternal and fetal morbidity and mortality.








TABLE 7.1 Fetal Radiation Doses Associated with Common Radiologic Examinations






































































































Type of Examination


Fetal Dosea (mGy)


Very-Low-Dose Examinations (<0.1 mGy)



Cervical spine radiography (anteroposterior and lateral views)


<0.001


Head or neck CT


0.001-0.01


Radiography of any extremity


<0.001


Mammography (two views)


0.001-0.01


Chest radiography (two views)


0.0005-0.01


Low- to Moderate-Dose Examinations (0.1-10 mGy)




Radiography





Abdominal radiography


0.1-3.0




Lumbar spine radiography


1.0-10




Intravenous pyelography


5-10




Double-contrast barium enema


1.0-20



CT





Chest CT or CT pulmonary angiography


0.01-0.66




Limited CT pelvimetry (single axial section through the femoral heads)


<1



Nuclear medicine





Low-dose perfusion scintigraphy


0.1-0.5




Technetium-99m bone scintigraphy


4-5




Pulmonary digital subtraction angiography


0.5


Higher-Dose Examinations (10-50 mGy)



Abdominal CT


1.3-35


Pelvic CT


10-50


18F PET/CT whole-body scintigraphy


10-50


Annual average background radiation = 1.1-2.5 mGy, 18F = 2-[fluorine-18]-fluoro-2-deoxy-D-glucose.


a Fetal exposure varies with gestational age, maternal body habitus, and exact acquisition parameters. CT, computed tomography; PET, positron emission tomography.


Modified from Tremblay E, Therasse E, Thomassin-Naggara I, Trop I, Quality initiatives: guidelines for use of medical imaging during pregnancy and lactation. Radiographics. 2012;32:877-911.



LABORATORY FINDINGS IN PREGNANCY

The numerous physiologic adaptations that occur in pregnancy often cause significant changes in normal laboratory values. Despite the well-understood and expected change in laboratory values, few laboratories provide healthcare providers with the normal reference ranges during pregnancy. Table 7.2 highlights the common reference ranges for basic laboratory values in pregnancy that impact the diagnostic workup of surgical conditions.15

Dec 30, 2020 | Posted by in EMERGENCY MEDICINE | Comments Off on Management of Common Surgical Conditions During Pregnancy
Premium Wordpress Themes by UFO Themes