Acs0903 The Pregnant Surgical Patient


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Acs0903 The Pregnant Surgical Patient

  1. 1. © 2007 WebMD, Inc. All rights reserved. ACS Surgery: Principles and Practice 9 CARE IN SPECIAL SITUATIONS 3 THE PREGNANT SURGICAL PATIENT — 1 3 THE PREGNANT SURGICAL PATIENT David C. Brooks, M.D., F.A.C.S., and Corrina Oxford, M.D. Approach to Abdominal Pain in Pregnant Patients Since the early 1990s, the number of live births in the United abortion at operation is highest during the first trimester.The opti- States has ranged from 3.88 to 4.12 million per year.1 mal time for elective surgery is during the second trimester Complications related to nonobstetric surgery are relatively because the uterus is smaller at that time than it is in the third uncommon, occurring in only 1% to 2% of pregnancies.2 trimester and because the fetus can be maintained in a relatively Management of the pregnant patient differs from that of other stable condition during the administration of general anesthesia. patients in several ways. First, pregnancy induces a variety of mechanical, hormonal, and chemical alterations that may confuse and mislead even the most experienced surgeon [see Discussion, Urgent Surgical Problems Physiologic Changes in Pregnant Patients, below]. Second, a sur- TRAUMA geon’s natural inclination, when faced with a pregnant patient experiencing abdominal pain, is to temporize. This tendency, Trauma is believed to occur which generally arises from the misconception that surgical inter- in approximately 6% to 7% of vention may injure the fetus, is responsible for delays in diagnosis gestations3—indeed, by some and ultimately for the unfavorable outcomes often associated with estimates, it may complicate as many as one in 12 pregnancies.4 acute abdominal pathology in pregnant patients. Third, pregnant Trauma remains the leading cause of maternal death, accounting patients require a multidisciplinary approach to care that involves for 46.3% of deaths during pregnancy.5 Homicide is the most the surgeon, the obstetrician, the radiologist, and the anesthesiol- common cause of traumatic maternal death, followed by motor ogist. Finally, and most important, a surgeon treating a pregnant vehicle accidents, accidental injury, and suicide.6 Motor vehicle woman is actually caring for two patients and has the same accidents account for 55% to 66% of all trauma during pregnan- responsibility to both. cy, falls account for 22%, and domestic abuse and assaults In what follows, we first review urgent surgical problems in the account for 21%. The more severe the injury to the mother, the pregnant patient, then discuss the physiologic changes of preg- greater the risk of injury to the fetus. When the mother survives, nancy and how these changes help shape general surgical princi- fetal death is most commonly related to abruptio placentae. Major ples in this population. Finally, we address certain nonurgent sur- trauma causes placental abruption in 40% to 66% of cases; minor gical problems associated with pregnancy. trauma causes placental abruption in 5% of cases.7 Signs and symptoms of abruption typically become manifest within 4 hours of observation; however, a delayed presentation may also occur. In Initial Management a patient with a history of trauma and potential abruption, persis- Initial management of any tent contractions are an indication for continued monitoring. Fetal pregnant patient presenting death may also result from complications of premature delivery or with an acute abdomen or an from direct penetrating injury to the fetus. acute surgical problem should include a thorough history and Blunt Injury physical examination [see 5:1 Acute Abdominal Pain], with particu- In the mother, blunt trauma (as in motor vehicle accidents) may lar consideration given to historical aspects of the pregnancy, the cause multiple life-threatening injuries, including head trauma, expected date of delivery, and the presence of any pregnancy-relat- intra-abdominal hemorrhage, pelvic fracture, and uteroplacental ed complications. Whenever possible, an obstetrician should be vascular injury. Pelvic fractures are a particular concern: because consulted and included in the decision-making process. Initial of the extensive vascular supply in this area, there is a significant maneuvers should include administration of supplemental oxy- risk of substantial hidden blood loss. Because the uterus consumes gen, placement of an I.V. line with the capacity to deliver ample approximately 20% of the cardiac output (i.e., 500 to 600 amounts of fluid or blood, insertion of a nasogastric tube if signif- ml/min), a uterine injury can place a pregnant woman at substan- icant vomiting is present, and performance of routine laboratory tial risk for massive hemorrhage within a short period. Uterine evaluations, such as a complete blood count, assessment of serum expansion displaces the bladder into the abdomen, thereby electrolyte levels, and urinalysis. If the pregnancy has passed the increasing the risk of traumatic bladder injury. The upper urinary 24th week, a fetal monitor should be employed. Radiographic tract is generally spared from injury, however, because the gravid investigations should be kept to a minimum, though abdominal uterus shields the retroperitoneum from direct injury. It should be and pelvic ultrasonography may be especially useful not only in kept in mind that mild hydroureter is physiologic in pregnancy. assessing the maternal pathology but also in evaluating the fetus. Hepatic, splenic, and uterine injuries are common in high-speed Acute abdominal surgical problems must be dealt with imme- motor vehicle accidents, but injuries to the GI tract, surprisingly, diately. Management of less acute problems, however, must take appear to be uncommon, largely because of the protective effects into account the stage of the pregnancy. The risk of spontaneous of the gravid uterus.8 Direct injury to the fetus as a result of blunt
  2. 2. © 2007 WebMD, Inc. All rights reserved. ACS Surgery: Principles and Practice 9 CARE IN SPECIAL SITUATIONS 3 THE PREGNANT SURGICAL PATIENT — 2
  3. 3. © 2007 WebMD, Inc. All rights reserved. ACS Surgery: Principles and Practice 9 CARE IN SPECIAL SITUATIONS 3 THE PREGNANT SURGICAL PATIENT — 3
  4. 4. © 2007 WebMD, Inc. All rights reserved. ACS Surgery: Principles and Practice 9 CARE IN SPECIAL SITUATIONS 3 THE PREGNANT SURGICAL PATIENT — 4 trauma is unusual because of the protection afforded by the mater- manage low-velocity penetrating injuries remains somewhat con- nal abdominal wall and the uterus. Blunt trauma may result in troversial. Low-velocity injuries above the fundus of the uterus are fetal skull fractures, fetal intracranial hemorrhage, or abruptio pla- almost always associated with visceral injury and thus call for centae; nevertheless, fetal demise is rare in this setting and usually exploratory laparotomy. Injuries occurring below the fundus and is secondary to maternal demise. anteriorly are seldom associated with visceral injury8 and thus can Many women refrain from using seat belts during pregnancy generally be managed nonoperatively. Subsequent laparotomy is because of discomfort or out of concern that the seat belt might indicated for worsening maternal symptoms. Subsequent cesarean injure the fetus; however, this practice has no effect on fetal death section is indicated for a viable fetus in distress. rates in automobile accidents. When unbelted women are ejected Domestic or partner violence during pregnancy occurs in 7% to from an automobile, maternal mortality is 33% and fetal mortali- 23% of all pregnancies.13 If the patient is in an abusive relation- ty is 47%.9 Three-point restraint is the safest choice for pregnant ship, the severity and frequency of assault typically increase during women in motor vehicles. pregnancy.14 In addition, 20% of abused pregnant women attempt suicide15 or abuse alcohol or drugs. Abuse has many far-reaching Penetrating Injury consequences for the mother and the fetus that cannot be accu- Penetrating injury is usually more damaging to the fetus than to rately measured. Unfortunately, partner violence often goes undi- the mother. Mortality is actually lower for pregnant women with agnosed and hence untreated: as few as 12% of abused women are penetrating injuries than for nonpregnant women with similar correctly identified in emergency room settings.16 Typical presen- injuries, presumably because of the shielding effect of the uterus tations of partner abuse include multiple injuries in various states and the fetus.10 of healing, inconsistent explanations of the injuries, minimization Penetrating trauma, however, often results in direct fetal injury. of the injuries, and delay in seeking medical attention.17 The face Fetal mortality in this setting ranges from 40% to 70%, whereas and the abdomen are struck more frequently during pregnancy. If maternal mortality ranges from 5% to 10%.11 In the first a suspicion of partner violence arises, the physician should ask trimester, trauma generally poses little direct threat to fetal viabil- direct questions about threats and should provide appropriate ity because the uterus is protected within the pelvis. In the second contacts and support. A well-documented evaluation, unedited and third trimesters, however, when the uterus is located within quotes, and careful drawings or pictures are also necessary in case the abdomen, penetrating trauma may result in direct fetal injury the patient wishes to take legal action immediately or in the future. or rupture of the membranes. With penetrating abdominal trau- In all 50 states, domestic violence is a crime, and in some, failure ma, the prognosis depends on which and how many organs are to report suspected violence is a crime as well. injured. General principles of trauma management are applied when the Management need for laparotomy is under consideration.Visceral injury occurs Trauma is managed in essentially the same way in pregnant 95% of the time if the peritoneum has been penetrated.12 For this patients as in nonpregnant patients [see 7:1 Initial Management of reason, many authorities advocate exploratory laparotomy for all Life-Threatening Trauma and 7 Trauma and Thermal Injury]. The high-velocity penetrating injuries to the abdomen. How best to mother is the first priority: stabilization of the mother improves Figure 1 Enlargement of the uterus to accommodate the developing fetus shifts intra-abdominal contents superiorly and compresses retroperitoneal structures. These effects are particularly impor- tant during the second and third trimesters.
  5. 5. © 2007 WebMD, Inc. All rights reserved. ACS Surgery: Principles and Practice 9 CARE IN SPECIAL SITUATIONS 3 THE PREGNANT SURGICAL PATIENT — 5 Table 1—Radiation Dose Absorbed by Unshielded of intra-abdominal hemorrhage in cases of blunt trauma.20 A Gravid Uterus from Radiographic Studies Often Kleihauer-Betke test for fetal red blood cells in the maternal cir- culation will reveal any fetomaternal hemorrhage present. Performed in Trauma Patients (Fetomaternal hemorrhage is the passage of fetal blood into the maternal vascular system; it occurs more frequently in pregnant Radiographic Study Unshielded Uterine Dose (mGy) women who have suffered traumatic injury than in those who have Cervical spine No detectable contribution not, and it can lead to fetal anemia, arrhythmias, and fetal exsan- Chest (AP) 0.003–0.043 guination.21) In Rh-negative mothers, a 300 µg dose of RhO(D) Pelvis (AP) 1.42–4.86 immune globulin will be protective against exposure to as much as Abdomen (AP) 1.33–4.51 15 ml of fetal cells (30 ml of RhD-positive whole blood). Rarely IVP 2.02–8.15 does fetomaternal hemorrhage exceed this level. Tetanus toxoid Full spine (AP) 1.54–5.27 should be administered when indicated. Femur (AP) 0.016–0.12 Early determination of gestational age by means of ultrasonog- Humerus (AP) < 0.00001 Cystography 1.35–4.41 raphy is a critical guide to further management decisions. CT scan Ultrasonography can also be used to monitor fetal heart tones, Head < 0.5 fetal activity, and amniotic volume. After the 20th week of gesta- Thorax < 10 tion, cardiotocographic monitoring is an important adjunct for Upper abdomen < 30 determining fetal status after trauma. Such monitoring should also Cumulative dose (without CT scan) 7.68–27.36 be employed in the event of preterm contractions. As many as Cumulative dose (with CT scan) > 7.68–67.86 40% of women experience preterm contractions, but only 3% AP—anteroposterior—IVP—intravenous pyelography progress to premature delivery.7 Preterm contractions in a preg- nant trauma patient should initiate an evaluation for abruptio pla- centae, uterine hemorrhage, and intra-abdominal hemorrhage. both maternal and fetal survival. Initial measures include efforts to Given that placental abruption occurs in 66% of cases of major support the airway, breathing, and circulation (the ABCs). The trauma and 5% of cases of minor trauma, the patient should be physiologic alterations characteristic of pregnancy affect maternal evaluated for ruptured membranes. Placental abruption usually responses to injury [see Discussion, Physiologic Changes in occurs within 4 hours of injury. Ultrasonography is not sensitive Pregnancy, below]. enough to detect this condition22; therefore, cardiotocographic Hypovolemia can be masked by the increased blood volume monitoring should be continued for 4 to 6 hours after stabilization and enhanced cardiac output of the pregnant patient.Tachycardia and longer if any irregularity in the mother or fetus is noted.23 If and hypotension may not be accurate indicators of hypovolemia: the fetus has not yet reached the gestational age of 23 weeks or is as much as 2 L, or 30% of maternal blood volume, may be lost not viable, the mother should receive supportive care. In these cir- before hemodynamic instability is detected.18 The expansion of cumstances, cesarean section is reserved for cases of disseminated intravascular fluid volume that occurs in pregnancy affects the intravascular coagulation (DIC). If the fetus is viable and the amount of replacement fluid needed. In the third trimester, mother stable, cesarean section can be carried out safely; if the patients should receive 1.5 times the amount of fluid that would fetus is viable and the mother unstable as a result of trauma, ordinarily be given to compensate for this effect. Use of military cesarean section should be carried out with the exploratory laparo- antishock trousers (MAST) may decrease maternal venous return tomy.7 When the need for concurrent hysterotomy is under con- by compressing the uterus on the inferior vena cava; accordingly, sideration, however, each case must be assessed individually. their use is not recommended. Vasoconstrictive agents should Typically, surgical intervention for a worrisome fetal heart tracing never be used for hemodynamic stabilization until hypovolemia is not carried out until after the 24th week of pregnancy. Patients has first been treated. Epinephrine and norepinephrine lead to undergoing an emergency cesarean section should receive a uteroplacental vasoconstriction and fetal compromise; ephedrine broad-spectrum antibiotic preoperatively. and phenylephrine may be used during pregnancy. In the event of acute maternal decompensation that does not An important concern with advancing gestation is the possibil- respond to standard resuscitative measures, a cesarean section ity that the expansion of the gravid uterus [see Figure 1] can pro- may be appropriate. In cases of particularly severe trauma, emer- duce aortocaval compression, leading to supine hypotension. Left gency operative resuscitation should be considered. If the patient lateral displacement of the uterus is necessary to improve blood is in cardiac arrest, thoracotomy and open chest massage, with flow to both the mother and the fetus after the 20th week. concurrent cesarean section if the fetus is viable, have been rec- There are very few diagnostic procedures for which pregnancy ommended.6 Cesarean section may increase maternal circulating is a contraindication. Radiographic investigation should be per- volume. Occasionally, cardiopulmonary resuscitation (CPR) is formed whenever necessary if the results are expected to affect more effective after the gravid uterus is emptied.There is also less management. It is usually possible to keep the total absorbed radi- risk of supine hypotension after cesarean section, though the ation dose below the level that is thought to increase teratogenic associated surgical blood loss may exacerbate maternal instabili- risk (i.e., 50 to 100 milliGrays [mGy]) [see Table 1].19 Plain films of ty. Timing is critical: if anoxia is limited to 4 to 6 minutes, the the cervical spine provide useful information on head and neck fetus generally will not be harmed. Therefore, any attempt to injuries; computed tomographic scanning of the abdomen with deliver the fetus should begin within 4 to 6 minutes after mater- contrast may offer the greatest amount of information on injuries nal cardiac arrest. If the fetus appears to be still viable after this to the retroperitoneum, the peritoneum, and the pelvis. period has passed, cesarean section should be performed; isolat- Ultrasonography is now being used for acute trauma assessment ed cases of fetal salvage after prolonged maternal anoxia have in both pregnant and nonpregnant patients; the results to date been reported. The survival of the fetus after delivery is depen- have been good. Peritoneal lavage done in an open fashion dent on its having reached a gestational age greater than 28 through a supraumbilical incision may facilitate rapid assessment weeks. CPR of the mother should be continued during and after
  6. 6. © 2007 WebMD, Inc. All rights reserved. ACS Surgery: Principles and Practice 9 CARE IN SPECIAL SITUATIONS 3 THE PREGNANT SURGICAL PATIENT — 6 the delivery because it may improve maternal status and survival. Commission on Radiological Protection (ICRP), which is 100 Two caveats should be kept in mind: (1) cesarean section mGy.35 With plain films, the chance of obtaining valuable infor- should not be performed in an unstable patient because of an mation is seldom worth the risk associated with the radiation. In anticipated cardiac arrest, and (2) if CPR is successful before sur- certain cases, magnetic resonance imaging may be helpful for fur- gical delivery is attempted, cesarean section should not be per- ther delineation of the source of pain without the risk posed by formed, because in utero resuscitation is likely.24 In utero resusci- ionizing radiation. tation may have to be continued for 10 to 20 minutes before reas- Because MRI does not expose the fetus to radiation and is suring elements reappear on a fetal heart tracing. known to be safe overall in the setting of pregnancy, it has become an increasingly attractive diagnostic imaging modality for identify- APPENDICITIS ing intra-abdominal pathology in the pregnant patient. Currently, Appendicitis is the most MRI is also being used to help diagnose appendicitis. In one small common surgical problem in series, MRI had an overall sensitivity of 100%, a specificity of pregnancy, occurring in 93.6%, and an accuracy of 94.0% in the evaluation of potential 0.05% to 0.1% of pregnan- acute appendicitis.36 Its negative predictive value was 100%.These cies, but it occurs no more results suggest that MRI is an excellent tool for excluding acute often in pregnant women than appendicitis in pregnant women with acute abdominal pain whose in nonpregnant women.25,26 The incidence is approximately the appendix cannot be visualized by means of ultrasonography.36 same in all three trimesters.The low maternal mortality—0.5% in This approach has not yet been widely accepted, and there is obvi- 1977 and 0% in recent studies27—notwithstanding, of all surgical ously a need for larger studies to confirm its value; however, the problems during pregnancy, appendicitis causes the most fetal findings to date indicate that the use of MRI in obstetric patients loss.28 The particular dangers of appendicitis in pregnancy lie in with appendicitis is a promising strategy. the varied presentation of symptoms, the higher chance of delayed diagnosis, and the significant risk that surgery presents to the fetus. Differential Diagnosis The symptoms of appendicitis mimic symptoms of normal The condition most often confused with appendicitis is pregnancy—namely, anorexia, nausea, vomiting, and abdominal pyelonephritis, which occurs in 1% to 2% of pregnant women. discomfort. The most reliable symptom of appendicitis during The two diseases may present remarkably similar clinical pictures, pregnancy is periumbilical or diffuse abdominal pain that later especially when pyelonephritis occurs on the right side. Because of localizes to the right lower quadrant.29 Although as the gravid the mechanical effects of the gravid uterus on the ureter, uterus grows, it pushes the appendix cephalad and posteriorly, pyelonephritis is more common in pregnant women than in non- right lower quadrant pain remains the most consistent symptom pregnant ones. Furthermore, urinalysis yields abnormal results— of appendicitis in any trimester.29 either pyuria or hematuria—in as many as 20% of patients with On physical examination, appendicitis presents with tenderness appendicitis as a result of extraluminal irritation of the ureter by in the right lower quadrant. It can be differentiated from adnexal the inflamed appendix.37 Nephrolithiasis can also be mistaken for or uterine pain with the help of the Adler sign: if the point of max- appendicitis; it should be seriously considered whenever acute imal tenderness shifts medially with repositioning on the left later- abdominal pain is present on the right side. Management of al side, the etiology is generally adnexal or uterine. Abdominal ureteral stones in pregnant patients presents a substantial chal- guarding, rebound tenderness, or referred tenderness is present in lenge to both the surgeon and the urologist. Newer techniques, 60% to 70% of patients with appendicitis; however, these findings such as stenting38 and placement of percutaneous nephrostomy are less common during the third trimester because of the laxity of tubes,39 have been successful in obviating surgical intervention. the abdominal wall muscles.30 Elevated body temperature is not a Right lower quadrant pain during early pregnancy may also be consistent finding in pregnant patients with appendicitis.27,29 a presentation of ectopic implantation. Typically, a patient misses Laboratory values can be misleading, in that pregnancy can a period and then experiences some degree of vaginal bleeding or cause a leukocytosis as high as 15,000 leukocytes/mm3 in the spotting. Abdominal or pelvic pain as well as cervical motion ten- absence of any source of infection.31 The white cell differential is derness is present, and a mass is often appreciated on pelvic exam- more useful than the absolute count; increased levels of band cells ination. When ectopic pregnancy is suspected, a serum human or immature forms suggest that the leukocytosis may be secondary chorionic gonadotropin (hCG) assay should be performed along to an infectious process. A urinalysis is necessary to rule out a uri- with transvaginal ultrasonography. If the serum hCG level is high- nary tract infection, which occurs in 10% to 20% of pregnant er than 2,000 IU/L and an intrauterine gestational sac is not visu- women. alized by transvaginal ultrasonography, laparotomy or laparoscopy Diagnostic radiology should be employed deliberately and judi- is indicated. ciously. Ultrasonography of the lower abdomen or transvaginal Torsion of an ovary or an ovarian cyst is also difficult to dis- ultrasonography can often visualize an inflamed appendix without tinguish from appendicitis.40 Although rare in pregnant risk to the fetus. It can also distinguish other causes of abdominal patients, torsion of an ovarian cyst may occur in the early stages pain, such as an ovarian cyst. The clinical presentation and an of the pregnancy. The physical examination is notable for pain ultrasonogram are often sufficient to establish the diagnosis of in the right or left adnexa and the occasional presence of a ten- appendicitis.32,33 der mass. Transvaginal ultrasonography will frequently detect In very rare cases, a CT study of the pelvis should be done as the cyst. Treatment requires laparotomy. The differential diag- well to elucidate a complicated presentation. A pelvic CT study nosis of acute abdominal pain in pregnancy should also include yields a total radiation dose of 25 mGy, and a directed helical, or ovarian cysts, mesenteric adenitis, degenerating fibroid tumors, spiral, CT study yields a total exposure of 30 mGy. Directed spi- salpingitis, inflammatory bowel disease, cholecystitis, ovarian ral CT has a sensitivity and specificity of 98%.34 For both pelvic vein thrombosis, ruptured corpus luteum, rectus hematoma, CT and directed spiral CT, the total radiation doses are well below round ligament pain, abruptio placentae, chorioamnionitis, and the threshold of safety established by the International adhesions.
  7. 7. © 2007 WebMD, Inc. All rights reserved. ACS Surgery: Principles and Practice 9 CARE IN SPECIAL SITUATIONS 3 THE PREGNANT SURGICAL PATIENT — 7 Management abscess formation is noted, I.V. antibiotics should be administered. When there is evidence of appendicitis and no alternative diag- The premature delivery rate for pregnant women undergoing nosis seems likely, operative intervention is warranted no matter appendectomy ranges from 13% to 22%; this increased rate may what stage the pregnancy has reached.41 The risk of the procedure contribute to the lower birth weights reported after maternal to mother and child is minimal in comparison to the risks posed appendectomy.25,29 The risk of premature delivery is especially by delayed diagnosis, perforation, and abscess formation. high during the first week after appendectomy. Given that tocolyt- Appendectomy in a pregnant patient does not increase the inci- ics have never been shown to improve outcome in this setting, dence of congenital malformation or stillbirth.26 With routine sur- beta2-receptor agonists are a better choice30; they are indicated gical management, maternal mortality is negligible and fetal mor- when advanced appendicitis is suspected or when active contrac- tality is 2% to 8%.27,42 For a ruptured appendix, maternal mortal- tions have been documented. ity is 1% and fetal mortality is as high as 35%.40,43 Negative laparo- INTESTINAL OBSTRUCTION tomy rates of 15% or lower are considered acceptable in the non- pregnant population, but negative laparotomy rates as high as 35% The incidence of bowel are considered acceptable in pregnant patients in the light of the obstruction [see 5:4 Intestinal grave consequences of delayed diagnosis.43 Obstruction] in pregnant For appendectomy in the pregnant patient, a right lower quad- patients ranges from one in rant muscle-splitting approach should be employed over the point 1,500 to one in 66,000.47 The of maximal tenderness.With late trimester pregnancies, this point most common cause of small- of maximal tenderness may be higher than the traditional bowel obstruction during pregnancy is adhesions, which account McBurney’s point [see 5:31 Appendectomy].The patient should also for 55% of cases; volvulus accounts for 25% of cases, with hernia, be turned 30° to the left to reduce pressure on the inferior vena cancer, and intussusception accounting for the remainder.48,49 As cava and to facilitate exposure of the cecum. If there is doubt the incidence of operative procedures and the average age of the about the diagnosis, a low midline incision or a right paramedian mother at gestation have risen, the likelihood of adhesive obstruc- incision should be made, especially if the patient has diffuse peri- tion has risen as well.This problem may be further exacerbated by tonitis. If appendicitis is found at the time of laparotomy, no fur- the hypomotility or dysmotility known to occur during pregnan- ther investigation for other intra-abdominal processes should be cy.50 The need for laparotomy and lysis of adhesive bands during performed; such investigation may disseminate the infectious pregnancy is extremely low; however, when surgical management process and lead to late pelvic or abdominal abscesses. If, howev- is necessary, fetal mortality is 26% and maternal mortality 5%. er, appendicitis is not found, the surgeon should thoroughly exam- With intestinal obstruction, the main concern is to ensure that ine the peritoneal contents on the right side of the abdomen, tak- diagnosis is not delayed. Accordingly, any pregnant patient pre- ing care to avoid exerting traction on the uterus, which might lead senting with nausea, vomiting, and a history of abdominal surgery to preterm labor. Appendectomy is advisable to avoid later confu- should be presumed to have a small-bowel obstruction until it is sion. If perforation occurs, the abdomen should be irrigated and proved otherwise. drained. Skin closure should be avoided if abscess, advanced per- Large-bowel obstruction is less common than small-bowel foration, or gangrene is encountered. obstruction but can be seen more often as pregnancy progresses. Laparoscopic appendectomy, like all laparoscopic procedures, is The most common cause of large-bowel obstruction is cecal or controversial in the setting of pregnancy [see Discussion, sigmoid volvulus. Volvulus during pregnancy is associated with a Laparoscopic Surgery in Pregnancy, below].When the diagnosis of 21% to 43% mortality.51 Colonic pseudo-obstruction, or Ogilvie appendicitis is uncertain, a laparoscopic approach can help rule out syndrome, has also been reported late in pregnancy or in the early salpingitis, adnexal mass, or ectopic pregnancy.30 When diffuse puerperium.52 Striking colonic dilatation without anatomic peritonitis is present, however, laparoscopy is associated with high- obstruction is apparent, with gas filling the entire length of the er complication rates than laparotomy is.30 The ideal surgical colon from cecum to rectum. The danger of cecal perforation is approach to appendectomy during pregnancy remains to be deter- high when the maximum diameter of the cecum exceeds 12 cm. mined. To date, no study of sufficient statistical power has shown the laparoscopic approach to possess any clear advantages, though Management some studies and some anecdotal experience have suggested that Any sign of bowel ischemia or perforation in a pregnant patient such advantages may exist.44 In one retrospective series, complica- with intestinal obstruction should prompt immediate operation. tion rates did not differ statistically between patients who under- For small-bowel obstruction, a nasogastric tube should be insert- went laparoscopic appendectomy and those who went open appen- ed, fluid resuscitation should be initiated, a Foley catheter should dectomy, but there were two cases of second-trimester fetal demise be placed, and a full battery of blood tests should be performed, in the laparoscopy group, a finding that may be of concern.45 including assessment of blood gas levels and electrolyte levels and For a laparoscopic appendectomy in a pregnant patient, the first a complete blood count. Because of the leukocytosis known to trocar (i.e., that for the camera) is placed in the subxiphoid area occur in pregnancy, close attention should be paid to the differen- under direct vision via an open technique; this step allows visual- tial blood count. Any sign of increasing acute-phase activity may ization of all pelvic structures and the appendix. Once the appen- suggest ischemia or perforation. Evaluation of acid-base status dix has been visualized, the right upper quadrant and right lower may also be useful in assessing bowel viability. A flat-plate and an quadrant trocars should be placed under direct vision. If the size upright abdominal film can confirm the diagnosis of small-bowel and position of the uterus make laparoscopic appendectomy diffi- obstruction and rule out free air.The risk of radiation exposure to cult or impractical, the camera can be used to help locate the best the fetus must be weighed against the potential morbidity and available spot for an open incision.46 mortality of a missed diagnosis. Antibiotics should be given preoperatively. Postoperative wound Once ischemia and perforation are ruled out, small-bowel infection can be minimized if adequate attention is paid to aseptic obstruction should be treated with aggressive fluid resuscitation to technique and handling of tissues. If perforation, peritonitis, or ensure euvolemia and correction of electrolyte abnormalities. If
  8. 8. © 2007 WebMD, Inc. All rights reserved. ACS Surgery: Principles and Practice 9 CARE IN SPECIAL SITUATIONS 3 THE PREGNANT SURGICAL PATIENT — 8 long-term bowel rest is anticipated, total parenteral nutrition junction with hydronephrotic kidneys; they are thought to be sec- should be considered [see 8:23 Nutritional Support]. If conservative ondary to the physiologic hydronephrosis seen in pregnancy. management does not lead to resolution, prompt operative inter- Ultrasonography is the best imaging technique for diagnosis of vention maximizes the chances of an excellent outcome for both renal rupture.55 Splenic rupture is the most common nonobstetric fetus and mother.30 A vertical incision allows the best exposure. cause of intra-abdominal hemorrhage during gestation. It usually The entire bowel must be examined for points of obstruction and occurs in conjunction with splenic artery aneurysms or sponta- assessed for viability. Segments of necrotic bowel should be resect- neous capsular rupture. In most cases, it is probably secondary to ed, and an ostomy should be fashioned if necessary. the increased blood volume and splenic enlargement seen toward Large-bowel obstruction is usually caused by volvulus. Sigmoid the later part of pregnancy. Esophageal rupture has also been volvulus can usually be reduced by rigid or flexible sigmoidoscopy. described, generally in association with heavy vomiting. Patients If sigmoidoscopy fails, operative intervention with bowel resection report sudden epigastric pain on vomiting that may radiate to the and possible colostomy is indicated.30 Treatment of a recognized back and the chest. X-rays may reveal air in the mediastinum. An cecal volvulus involves prompt operative intervention, resection of upper GI series with water-soluble contrast material will demon- any threatened bowel, and cecopexy to prevent recurrence. strate the site of the rupture. Although esophageal rupture is not Pseudo-obstruction should be managed initially with bowel more common in pregnancy, it may be associated with the fre- rest, electrolyte replacement, and the placement of a rectal tube. If quent nausea and vomiting seen with hyperemesis gravidarum. these conservative measures fail to reestablish normal peristaltic Ultrasonography, radionuclide scanning, and, ultimately, angiog- activity, colonoscopy and intraluminal aspiration of the gas-filled raphy may be helpful in diagnosing rupture of the liver, the kidney, colon should be tried.This approach is effective in as many as 85% or the spleen. of cases; however, it should be undertaken only by a skilled endo- scopist because the potential for iatrogenic perforation of the Management bowel is extremely high. If there is no change in the size of the Prompt institution of volume support is essential, followed by colon after 72 hours, a cecostomy is indicated. emergency surgery and correction of any coagulopathy. Conservative management is reserved for stable patients with non- PERFORATED DUODENAL expanding subcapsular hematomas. Serial ultrasonography is indi- ULCER cated. If adequate assessment of the hematoma, expanding Although rare, perforated hematoma, or rupture proves difficult or impossible, the patient duodenal ulcer has been should be taken to the OR for surgical treament.56 reported. When it occurs, it Operative management of hepatic rupture or expanding poses an extremely serious hematoma involves debridement of nonviable liver, hemostasis threat to both mother and with electrocoagulation or packing, and adequate drainage. fetus. There is no place for expectant, nonoperative therapy: Cesarean section should be performed simultaneously, depending prompt operative intervention is crucial. Surgical therapy should on the gestational age and the likelihood of fetal survival. This be directed at plication of the perforation, and no attempt should maneuver, when indicated, is curative. Maternal mortality as high be made to perform a definitive ulcer operation. If the woman is as 50% to 75% has been reported, even with prompt surgical inter- close to term, the child should be delivered vaginally rather than vention. Fetal mortality can be even higher, reaching nearly 80% by cesarean section because of the prohibitive risk of uterine con- in some series.57 Renal rupture necessitates urgent operative explo- tamination. ration. Every effort should be made to salvage the ruptured kidney. Suspected splenic rupture necessitates immediate laparotomy and SPONTANEOUS VISCERAL splenectomy. Esophageal rupture is treated with immediate repair RUPTURE through the left chest, if the injury is to the lower portion of the Spontaneous rupture dur- esophagus, or through the right chest, if the injury is to the upper ing pregnancy can involve the portion. liver, the kidney, the spleen, or the esophagus. Spontaneous hepatic rupture during pregnancy is extremely uncommon, occur- Conditions for Which ring no more frequently than one in 50,000 pregnancies and per- Medical Management haps as infrequently as one in 250,000 pregnancies.53 It is thought Should Be Attempted to be an advanced development in preeclampsia or eclampsia. BILIARY TRACT DISEASE Abdominal trauma and events that increase intra-abdominal pres- sure (e.g., sudden coughing, sneezing, or unusually strong con- Acute cholecystitis is the tractions) have also been implicated as causes of spontaneous rup- second most common nonob- ture. Rupture may occur during the second or third trimester, dur- stetric emergency in pregnant women. Symptomatic gallstone dis- ing delivery, or even in the early postpartum period. Typically, it ease is far more common in women than in men because of the develops in older, multiparous women in the third trimester.54 differential effects of the sex steroids on bile lipid composition and Patients present with several days of severe right upper quadrant cholesterol saturation.58 The difference in incidence begins at or substernal pain radiating to the back.The pain may precede the menarche, increases during the childbearing years, and decreases actual rupture by as much as a few days. Nausea, vomiting, hyper- at menopause. By the age of 75 years, at least 35% of women and tension, coagulopathy, and thrombocytopenia are frequently pre- 20% of men have gallstones.59 sent. In some cases of rupture, the patient presents with hypo- Gallstone disease is a result of cholesterol supersaturation and volemic shock. A right upper quadrant ultrasonogram often visual- biliary stasis, both of which are promoted by pregnancy.60 The izes the rupture or the preceding subcapsular hematoma.30 elevated estrogen levels during pregnancy increase cholesterol A limited number of renal ruptures have been described in con- secretion by the liver. Estrogen enhances hepatic cholesterol
  9. 9. © 2007 WebMD, Inc. All rights reserved. ACS Surgery: Principles and Practice 9 CARE IN SPECIAL SITUATIONS 3 THE PREGNANT SURGICAL PATIENT — 9 uptake, increases cholesterol synthesis, and inhibits catabolism of Management cholesterol to bile acids. High concentrations of cholesterol in the Initial management of cholecystitis is conservative, comprising bile overwhelm the solubilizing ability of bile salts, with the result I.V. hydration, bowel rest, administration of meperidine and that cholesterol stones form.61 Elevated progesterone levels lead antibiotics, fetal monitoring, and, if necessary, nasogastric decom- to bile stasis and decreased gallbladder contraction. Progesterone pression. This regimen is successful in 84% of patients.73 also causes incomplete emptying of the gallbladder after stimula- Operative intervention is indicated in the presence of any of the tion by cholecystokinin (CCK).62 The mechanisms are not following: failure of conservative management, recurrent disease, understood, but it is thought that progesterone may decrease intractable nausea, maternal weight loss, fetal growth retardation, gallbladder reactivity to CCK.63 The decrease in small-bowel obstructive jaundice, gallstone pancreatitis, or peritonitis. Thus, motility that occurs secondary to progesterone elevation may serial monitoring of liver function test results and amylase levels is alter enterohepatic circulation and decrease bile acid return to essential during conservative therapy. the liver.64 The balance of bile salts and cholesterol is further If cholecystectomy during pregnancy is necessary but not altered in such a way as to favor cholesterol supersaturation and urgent, it is best to perform the operation in the second trimester: stone formation. Pregnancy also alters the pool of bile acids.The fetal mortality from a first-trimester cholecystectomy can be as decreased percentage of chenodeoxycholic acid and the high as 12%.74 The rate of fetal loss decreases through gestation; increased percentage of cholic acid during pregnancy also pro- however, beginning in the third trimester, the risk of preterm labor mote stone formation. increases. Symptomatic gallstone disease is also a reasonable indi- The incidence of gallstone disease in pregnant women ranges cation for surgical management.68,75 Half of patients with symp- from 3.3% to 12.2%65 and increases with gestational age; howev- tomatic gallstone disease require repeat hospitalizations; in addi- er, only 30% to 40% of patients with gallstones are sympto- tion, several investigators have found the incidence of sponta- matic.66 The relative infrequency of symptomatic biliary disease is neous abortion, preterm labor, or premature delivery to be high- a function of the natural history of gallstones and of the time er in patients treated nonoperatively than in those undergoing required to precipitate sufficient stones to generate symptoms.67 cholecystectomy.76 If cholecystectomy is performed in the second Management of biliary colic consists of conservative therapy— or third trimester, fetal mortality is lower than 5%.77 namely, hydration, bowel rest if necessary, analgesia, and fetal There remains a degree of controversy regarding the relative monitoring. In pregnant patients, elective cholecystectomy for merits of conservative management and aggressive surgical inter- symptomatic gallstone disease should be delayed until after deliv- vention for patients with symptomatic gallbladder disease. In one ery. Fewer than 11% of symptomatic patients progress to a more study using a Markov decision analysis model that took into serious complication (e.g., cholecystitis, choledocholithiasis, or account all available English data, conservative (nonoperative) pancreatitis). Cholecystectomy during pregnancy is reserved for management was compared with laparoscopic cholecystectomy.78 recurrent biliary colic or the aforementioned complications. It fol- In the conservative management group, the estimated fetal mor- lows that cholecystectomy is rarely necessary in pregnant patients: tality was 7%, and the recurrence rates were 55%, 55%, and 40% it is undertaken once in every 10,000 live births.68 for the first, second, and third trimesters, respectively. The rate at Gallstone disease causes acute cholecystitis in only 0.05% to which emergency surgery was necessary after nonoperative man- 0.08% of births.68 The clinical symptoms of cholecystitis consist agement was 19.5%. In the laparoscopic group, the estimated of epigastric or right upper quadrant pain, fever, nausea, vomiting, fetal mortality was 2.5%. Accordingly, the authors concluded that and occasional radiation of the pain into the right scapula. laparoscopic cholecystectomy was superior to nonoperative man- Physical findings include tenderness in the right upper quadrant agement of biliary tract disease in the setting of pregnancy. and, occasionally, the Murphy sign. Elevated liver function test Surgical treatment during pregnancy consists of either open or results indicate that complicated biliary tract disease or choledo- laparoscopic cholecystectomy [see 5:21 Cholecystectomy and cholithiasis is likely; however, elevated alkaline phosphatase levels Common Bile Duct Exploration]. The advantages of laparoscopic are seen in normal pregnancies and thus are diagnostically over open cholecystectomy include earlier recovery, earlier mobil- unhelpful. ity, reduced use of narcotics, smaller incisions, and fewer surgical Ultrasonography can diagnose gallstones and biliary ductal site infections.76 When carried out with standard precautions, dilatation with an accuracy of 97%.60 It can also detect perichole- laparoscopic cholecystectomy does not increase the rate of fetal cystic fluid, reveal gallbladder wall thickening, and elicit a sono- loss (5%) or of spontaneous abortion, nor does it have a greater graphic Murphy sign, all of which are characteristic of cholecysti- adverse effect on birth weight, Apgar scores, or the rate of preterm tis.69 Radionuclide scans introduce the risk of fetal exposure to delivery than open cholecystectomy does.79 Laparoscopic chole- radiation.This risk almost always outweighs the potential value of cystectomy can be performed safely and effectively throughout any information to be gained from such a scan. pregnancy.79,80 The literature from the past 16 years clearly supports minimal- Differential Diagnosis ly invasive operative management of symptomatic cholelithiasis in The differential diagnosis of cholecystitis includes appendicitis pregnant women. The second trimester seems to be the optimal (see above), pyelonephritis, nephrolithiasis, acute pancreatitis (see time for a laparoscopic cholecystectomy: the uterus tends not to below), myocardial infarction, gastroesophageal reflux disease occlude the operative field as much as it does later in gestation. (GERD), peptic ulcer disease (see below), hepatitis, and hepatic Conservative, nonoperative management may place the patient at liver abscess. Significant hepatic syndromes can occur during risk for cholecystitis and gallstone pancreatitis, which are associat- pregnancy, such as intrahepatic cholestasis of pregnancy, acute ed with increased morbidity and a greater likelihood of sponta- fatty liver of pregnancy, infectious hepatitis, the hemolysis–elevat- neous fetal loss, preterm delivery, and repeated hospitalizations for ed liver enzymes–low platelet count (HELLP) syndrome, and symptomatic relief—developments that often end in operative eclampsia.70-72 These syndromes should be considered if the clin- management. Particular concerns with laparoscopic cholecystec- ical signs and symptoms observed in a pregnant patient do not tomy include a 0% to 5% risk of fetal mortality, a 0.1% risk of conform to the typical picture of gallstone disease. maternal mortality, and as much as a 7% risk of preterm labor.
  10. 10. © 2007 WebMD, Inc. All rights reserved. ACS Surgery: Principles and Practice 9 CARE IN SPECIAL SITUATIONS 3 THE PREGNANT SURGICAL PATIENT — 10 Often, a pregnant woman who has undergone the procedure may midabdominal but may radiate into the back; nausea, vomiting, experience increased uterine activity afterward; this can generally and anorexia are also typical symptoms. Findings in severe cases be controlled with tocolytic therapy as indicated. Prophylaxis include hypotension, hypovolemia, and a rapid, thready pulse. against thromboembolism is recommended, with an appropriate Jaundice occurs in patients with CBD stones.The hallmark of the dose of heparin administered preoperatively and pneumatic com- condition is diffuse abdominal pain combined with hyperamy- pression devices employed intraoperatively. The patient should be lasemia95; amylase levels may approach 2,000 to 3,000 U/L and maintained in the left lateral decubitus position to prevent com- may be accompanied by lipase elevations.96 Albumin, calcium, and pression of the inferior vena cava by the gravid uterus. The bilirubin levels should be measured and liver function tests per- Trendelenburg position should be used no more than is necessary. formed.The results should be interpreted with caution in the light Ideally, a Hasson technique should be employed, with several tro- of the alkaline phosphatase elevation known to occur in normal cars used for manipulation of the tissues and preferably with 30° pregnancies. Ultrasonography should be undertaken with the aim scopes.The patient’s end-tidal CO2 should be monitored and kept of searching for evidence of cholelithiasis and choledocholithiasis. between 25 and 33 mm Hg. If possible, the pneumoperitoneum Visualization of the inflamed pancreatic head may be informative; should be kept to 10 to 15 mm Hg; this level of pressure is associ- however, this structure is often difficult to locate. ated with the best outcomes for the procedure. General anesthesia is preferred; ideally, an obstetric anesthesiologist should be Management present.81,82 Treatment should be aimed at correction of the hypovolemia Routine indications for conversion to open cholecystectomy that invariably accompanies pancreatitis.97 Restriction of oral intake apply, including uncontrolled bleeding and unclear anatomy. is necessary. In cases of intractable nausea, a nasogastric tube Additionally, conversion during pregnancy is indicated if the should be placed. Intramuscular administration of meperidine at a gravid uterus has expanded to the point where safe dissection of dosage of 50 to 75 mg every 3 to 4 hours provides adequate anal- the gallbladder by laparoscopic means is impossible.80,83-86 If the gesia. Antibiotics should be reserved for treatment of a specific fetus shows signs of distress, deflation of the pneumoperitoneum infectious complication. Calcium levels should be kept within the and conversion to an open cholecystectomy may be necessary. normal range. Arterial blood gases should be monitored as indicat- Laparoscopic cholecystectomy is contraindicated in pregnant ed. Prolonged pancreatitis may necessitate lengthy periods of bowel patients with gallstone pancreatitis. rest. During extended periods without oral feeding, pregnant In patients with choledocholithiasis, intervention should be per- women should be maintained on total I.V. hyperalimentation.98 formed without delay. The common bile duct (CBD) should be In patients with pancreatitis caused by extrahepatic biliary explored by means of endoscopic retrograde cholangiopancreatog- obstruction, endoscopic management has achieved excellent raphy (ERCP) [see 5:18 Gastrointestinal Endoscopy], with fluo- results. ERCP and sphincterotomy [see 5:18 Gastrointestinal roscopy used economically and lead aprons worn to shield the Endoscopy] can both be performed safely during pregnancy. fetus.30 ERCP with sphincterotomy successfully addresses chole- Definitive treatment with cholecystectomy and intraoperative docholithiasis without increasing fetal mortality or the rate of cholangiography can safely be delayed until after delivery. preterm delivery.87 Surgical management of choledocholithiasis Operative intervention should be reserved for patients with biliary with open or laparoscopic cholecystectomy and CBD exploration obstruction in whom there is no evidence of stone passage. Efforts should be reserved for patients in whom ERCP fails. aimed at postponing operative intervention have been somewhat Choledocholithiasis with right upper quadrant tenderness, fever, successful, though the recurrence rate approaches 50%. Early and jaundice (Charcot’s triad) suggests cholangitis.The only treat- operative intervention has not been shown to improve fetal sur- ment options for cholangitis when ERCP fails are open cholecys- vival.90 During the first trimester, loss of the fetus is common99; tectomy and percutaneous intubation of bile ducts.88 Intra- however, in the second trimester, operative intervention has a good operative cholangiography can be used without problems after the chance of yielding excellent results for both mother and fetus.100 second trimester,89 provided that the fetus is shielded with lead Although unusual, pseudocyst formation has been reported in during imaging to limit radiation exposure. Duct imaging should pregnant women. It is managed conservatively, without operative be reserved for patients who have risk factors for CBD stones (e.g., intervention. Laparotomy, debridement, drainage, and cholecys- pancreatitis, a history of jaundice, or choledochal dilatation).30 tectomy are indicated for severe cases with pancreatic necrosis. PANCREATITIS PEPTIC ULCER DISEASE Pancreatitis is rare during pregnancy, occurring in every 1,000 During pregnancy, symptoms of upper abdominal pain, nausea, to 10,000 pregnancies.68 Its incidence, like that of gallstone dis- and vomiting are not uncommon. Peptic ulcer disease usually ease, increases with gestational age. Associated gallstone disease is begins with these same symptoms. Women with peptic ulcer dis- present in 70% to 90% of pregnant women presenting with pan- ease usually experience symptomatic improvement during preg- creatitis.68,87,90 Gallstone pancreatitis is associated with a maternal nancy. Elevated estrogen levels are believed to reduce gastric acid- mortality of less than 37% and a fetal mortality of 10% to 60%.89 ity during early pregnancy. Maternal gastrin production does not In the nonpregnant population, pancreatitis is associated with bil- change during pregnancy, but histamine-stimulated acid output is iary tract disease in only 40% of cases, with alcohol-induced pan- lower. During the third trimester, however, maternal serum gas- creatitis accounting for another 40%. In pregnant patients, pan- trin levels rise as a result of placental contribution, and sympto- creatitis can be secondary to hypertriglyceridemia,91 as well as to matic peptic ulcer disease may become more likely. During the late thiazide administration and hyperparathyroidism.92 At present, third trimester and the early postpartum period, basal and stimu- there is little evidence to suggest that pregnancy itself is an etio- lated acid production returns to normal. logic mechanism in the development of pancreatitis.93,94 The diagnosis is made in much the same way in pregnant The signs and symptoms of pancreatitis in pregnant women are patients as in nonpregnant ones, except that physicians treating indistinguishable from those seen in the general population. pregnant women should rely more on clinical information and less Patients report an unremitting, deep visceral pain that is usually on radiologic intervention. Intractable pain that is not relieved by
  11. 11. © 2007 WebMD, Inc. All rights reserved. ACS Surgery: Principles and Practice 9 CARE IN SPECIAL SITUATIONS 3 THE PREGNANT SURGICAL PATIENT — 11 the usual therapeutic interventions should prompt endoscopic appearance. Bleeding is observed, ranging from spotting with evaluation with a tissue biopsy for Helicobacter pylori culture. defecation to measurable loss. The disease is self-limited, almost never progressing to true IBD. Management Safe symptomatic relief can be achieved with direct-acting Management agents (bismuth salicylate, sucralfate, aluminum hydroxide, and Treatment of ulcerative colitis or Crohn disease involves admin- magnesium hydroxide). H2 blockers and proton pump inhibitors istration of sulfadiazine, steroids, or both.108 Treatment with both are reserved for symptoms refractory to direct-acting agents. Most of these agents is often recommended.109 Both steroids and sulfa- gastritis and ulcer disease is caused by infection by H. pylori. diazine have been reported to cause congenital malformations in Treatment with the usual array of antibiotics (clarithromycin, animal studies; however, because of the increased risk of fetal and amoxicillin, and metronidazole—but not tetracycline), direct-act- maternal mortality in untreated cases of IBD, it is recommended ing oral agents, and H2 blockers is also safe in pregnancy.101 that steroids and sulfadiazine be administered together as neces- Limitation of intake of nonsteroidal anti-inflammatory drugs sary to minimize the active effects of the disease.110 (NSAIDs), tobacco, and caffeine also helps mitigate symptoms. If the disease does not respond to medical management, oper- A perforated duodenal ulcer must be treated surgically [see ative intervention may be undertaken, but only as a last resort. In Urgent Surgical Problems, Perforated Duodenal Ulcer, above]. patients with ulcerative colitis, the most common indication for Surgery is also indicated if significant hemorrhage—necessitating operation is toxic megacolon, which, if left untreated, can cause transfusion of more than six units over a 24-hour period—is significant infant and maternal mortality. In patients with Crohn observed. In this setting, maternal mortality is 14% after opera- disease, the uncommon problems of abscess, fistula formation, tion; however, it is 44% if surgical treatment is not provided.102 and bowel obstruction may force operation; these conditions INFLAMMATORY BOWEL DISEASE should be treated in the usual fashion. Greater reliance should be Pregnancy does not affect either ulcerative colitis or Crohn dis- placed on fecal diversion in pregnant patients because of the ease to any great degree, nor do these diseases affect the welfare of increased risk of anastomotic dysfunction. Active Crohn disease the fetus appreciably.103-105 Active disease flare-ups are most com- may necessitate complete bowel rest and maintenance of nutrition mon during the first trimester and during the early postpartum by central I.V. feedings.111,112 period.106 In a review of pregnancies in patients with Crohn dis- In any pregnant patient with inflammatory bowel disease, par- ease, the outcome of the pregnancy was not adversely affected by ticularly Crohn disease, the mode of delivery must be carefully the disease.107 Although patients with active disease generally had considered. If the patient has active Crohn disease with rectal poorer outcomes, neither pregnancy nor therapy affected the involvement, vaginal delivery may be contraindicated, so as to course of the disease. avoid the potential consequence of rectovaginal fistula formation. In addition to these frank forms of inflammatory bowel disease Patients with ulcerative or granular proctitis should not receive (IBD), ulcerative or granular proctitis may also occur in pregnan- systemic treatment with steroids or sulfadiazine, because of the cy.This poorly understood disorder is confined entirely to the dis- potential toxicity to the fetus. Steroid enemas or enemas concoct- tal 10 cm of the rectum. Endoscopically, the mucosa manifests ed from an elixir preparation of sulfasalazine may be administered. multiple diffuse superficial ulcerations and friability. Above the Low-residue diets may help control particularly bothersome distal 12 to 15 cm of the rectum, the mucosa assumes a normal symptoms. Discussion Physiologic Changes of Pregnancy at 6 weeks to 150 ng/ml at term. Tidal volume increases by as A variety of physiologic alterations occur during pregnancy. much as 40% in pregnancy, thereby increasing minute ventilation. These include mechanical, hormonal, chemical, and hematologic With the upward displacement of the diaphragm, the widening of changes [see Table 2] that are essential for maintenance of the preg- the subcostal angle by about 50%, and the increase of about 5 cm nancy during the 40 weeks of gestation but that may also compli- in chest circumference, the result is a 20% decrease in the func- cate the evaluation of abdominal problems in the pregnant tional residual capacity (FRC), which reflects the amount of air patient. remaining in the alveoli at the completion of expiration. As FRC decreases, gas exchange decreases as a consequence of alveolar RESPIRATORY CHANGES collapse.This phenomenon has major implications for ventilation The respiratory system undergoes several measurable changes of the pregnant patient.114 as a result of the hormonal and physiologic influences of preg- In pregnant patients, both O2 consumption and CO2 produc- nancy. Elevated progesterone and estrogen levels cause blood vol- tion increase as gestation progresses. As the progesterone level ume and cardiac output to increase; as a result, pulmonary blood rises, chemosensitivity to CO2 and CO2 production increase, and flow increases. With the added component of decreased blood minute ventilation progressively rises by up to 30%.115 albumin concentration and thus decreased oncotic pressure, mild Progesterone and increased CO2 production are the main forces lung edema may ensue.113 Progesterone also acts as a direct respi- behind the condition known as hyperpnea of pregnancy.This con- ratory stimulant, increasing the chemosensitivity of the respirato- dition results in a reduction in arterial CO2 tension (PaCO2) from ry center to CO2. Stimulation of respiratory drive by progesterone 40 mm Hg to 34 mm Hg and an increase in arterial oxygen ten- may be the cause of a substantial proportion of the respiratory sion (PaO2) from 60 mm Hg to 100 mm Hg.This exaggerated gra- changes seen in pregnancy. Progesterone levels rise from 25 ng/ml dient between the mother and the fetus facilitates efficient
  12. 12. © 2007 WebMD, Inc. All rights reserved. ACS Surgery: Principles and Practice 9 CARE IN SPECIAL SITUATIONS 3 THE PREGNANT SURGICAL PATIENT — 12 Table 2—Chemical and Hematologic sory muscles.113 It can complicate the assessment of any pregnant Alterations in Pregnant Patients175 patient with an underlying surgical issue. In addition, pregnant women typically have decreased oxygen reserve and thus are sub- Normal Values ject to rapid development of hypoxia and hypercapnia with Laboratory Test hypoventilation or apnea. This vulnerability becomes especially Nonpregnant Pregnant important when such patients undergo intubation and anesthesia. Although dyspnea is common in pregnancy, any obstetric patient Urinary acetone Negative Faint positive who presents with acute shortness of breath should undergo a Serum total protein (g/dl) 6.5–8.5 6.8 Serum albumin (g/dl) 3.5–5.0 2.5–4.5 careful evaluation. Cardiovascular disease as a cause of dyspnea Blood urea nitrogen (mg/dl) 10–25 5–15 complicates 1% to 4% of pregnancies.117 Fasting blood glucose (mg/dl) 70–110 65–100 CARDIOVASCULAR CHANGES Two-hour postprandial blood glucose < 110 < 120 (plasma) (mg/dl) During pregnancy, cardiac output rises by 30% to 50% [see Serum calcium (mEq/L) 4.6–5.5 4.2–5.2 Table 3].This rise is attributable to an increased heart rate and, to Serum phosphate (mg/dl) 2.5–4.8 2.3–4.6 a lesser extent, an increased stroke volume.118 The HR increase Alkaline phosphatase (IU/L) 35–48 35–150 may begin as early as 6 weeks after conception119; by the third Cholesterol (mg/dl) 120–290 177–345 Triglycerides (mg/dl) 33–166 130–400 trimester, the HR is 15 to 20 beats/min faster than the baseline Serum folic acid (ng/ml) 5–21 4–14 rate. The increase in the plasma volume may be as great as 50%. Vitamin B12 (pg/ml) 430–1,025 Decreased Despite the increases in cardiac output and blood volume, BP Hemoglobin (g/dl) 12 > 11 actually decreases because of the overwhelming effect of reduced Hematocrit (%) 36 33 systemic vascular resistance. BP reaches a nadir in the second Serum iron (μg/dl) > 50 > 60 trimester and returns to baseline levels by the time of delivery.120 TIBC (μg/dl) 250–400 300–600 The gravid uterus may press on the inferior vena cava, decreas- % TIBC saturation 30 > 20 ing venous return and causing cardiac output to decrease by as Serum zinc (μg/dl) 65–115 55–80 much as 30%. Pregnant women may even experience dizziness or Urinary zinc (μg/dl) 200–450 200–450 syncope. To optimize cardiac output, the pregnant patient should TIBC—total iron-binding capacity be placed in the left lateral decubitus position.115 Cardiovascular evaluation of the pregnant patient must take into account the altered cardiac output, blood volume, HR, and exchange of gases.With the decreased PaCO2, the pregnant patient BP. Hypovolemia may not manifest itself as tachycardia or also experiences respiratory alkalosis in relation to the fetus. The hypotension, as would normally be predicted; alternatively, tachy- oxyhemoglobin dissociation curve is thus shifted to the right, again cardia of pregnancy may be mistaken for hemorrhage. Careful facilitating delivery of oxygen to the fetus.To prevent harmful pH analysis of the data is necessary whenever hypovolemia is under increases, the kidneys respond appropriately by excreting bicar- consideration. Additionally, pregnancy-associated signs and symp- bonate. Respiratory alkalosis with compensatory metabolic acido- toms may complicate any evaluation of concurrent heart disease sis is normal in pregnancy. [see Cardiovascular Conditions during Pregnancy, below].121 As pregnancy progresses, tidal volume rises as a result of the increased chest circumference. Although the growing uterus forces GASTROINTESTINAL CHANGES the diaphragm upward by as much as 4 cm, tidal volume is main- Appetite can vary greatly from one pregnant woman to anoth- tained, thanks to increased use of accessory muscles. By week 12 er. The average increase in daily intake is 200 kcal/day during the of gestation, FRC decreases by 10% to 25% as a result of first trimester.The recommended dietary allowance (RDA) is 300 decreased chest wall compliance. Relaxin, the hormone responsi- kcal/day during pregnancy—more if the pregnant patient is an ble for ligamentous relaxation of the pelvis, may also be responsi- adolescent or especially physically active.122 As many as 70% of ble for laxity of the chest wall ligaments. As a consequence of this pregnant patients experience nausea and vomiting. Nausea of laxity, the subcostal angle increases from 68° to 103°.116 pregnancy, or morning sickness, frequently occurs between weeks As many as 75% of pregnant women are affected by dyspnea. 4 and 16 of gestation. Most patients respond to conservative treat- Dyspnea of pregnancy comprises mild pulmonary edema, ment, including selective eating and avoidance of dehydration. increased breathing load, increased drive, and greater use of acces- Persistent nausea and vomiting, termed hyperemesis gravidarum, Table 3—Hemodynamic Values in Healthy Nonpregnant, Pregnant, and Postpartum Subjects118,176 Parameter Nonpregnant 36–38 Weeks’ Gestation* Postpartum Heart rate (beats/min) 60–100 83 ± 10 71 ± 10 Central venous pressure (mm Hg) 5–10 3.6 ± 2.5 3.7 ± 2.6 Mean pulmonary arterial pressure (mm Hg) 15–20 — — Pulmonary arterial wedge pressure (mm Hg) 6–12 7.5 ± 1.8 6.3 ± 2.1 Mean arterial pressure (mm Hg) 90–110 90.3 ± 5.8 86.4 ± 7.5 Cardiac output (L/min) 4.3–6.0 6.2 ± 1.0 4.3 ± 0.9 Stroke volume (ml/beat) 57–71 74.7 60.6 Systemic vascular resistance (dyne cm sec–5) • • 900–1,400 1,210 ± 266 1,530 ± 520 Pulmonary vascular resistance (dyne cm sec–5) • • < 250 78 ± 22 119 ± 47 *Values in pregnant patients were determined with patient in left lateral decubitus position.
  13. 13. © 2007 WebMD, Inc. All rights reserved. ACS Surgery: Principles and Practice 9 CARE IN SPECIAL SITUATIONS 3 THE PREGNANT SURGICAL PATIENT — 13 can lead to dehydration, electrolyte imbalance, and organ failure. acceptably safe if appropriate attention is given to certain key peri- It is important to exclude other possible causes of nausea before operative considerations—namely, fetal monitoring, radiologic attributing symptoms to nausea of pregnancy. This condition can investigation, anesthesia, and the timing of the operation. complicate the diagnosis of appendicitis, gallbladder disease, pan- FETAL MONITORING creatitis, or bowel obstruction. Between 40% and 80% of pregnant women experience Monitoring consists of measuring uterine contractions with a GERD.101 Esophagogastric junction tone decreases as intra- tocometer, fetal HR with a Doppler transducer, and fetal move- abdominal pressure increases, with reflux the result. In addition, ment and tone with ultrasonography. Together, these measure- under the influence of estrogen and progesterone, the stomach ments yield a good indication of fetal health. Preoperative ultra- exhibits decreased motility and an increased emptying time. sonography can also approximate gestational age when an accu- Transit through the small bowel and the colon is also slowed. Few rate history cannot be obtained. Gestational age plays a pivotal gastrointestinal changes have a critical impact on pregnancy. It role in all surgical decision making for a pregnant patient. should be kept in mind, however, that prolonged emptying time The fetal HR is routinely measured both preoperatively and and other effects of progesterone increase the likelihood of aspira- postoperatively.131 Though the fetal HR can be heard 14 weeks tion with general anesthesia.123 after conception, it serves as an indicator of fetal oxygenation only Estrogens and progesterone are thought to influence cholesta- after week 26. Specific fetal HR abnormalities—absence of vari- sis of pregnancy as well. The net effect of the two hormones is to ability, late or variable decelerations, and bradycardia—are pre- increase the cholesterol concentration in bile. Estrogen also dictive of impending fetal hypoxia, physical damage, or death. In decreases bile flow. Progesterone promotes smooth muscle relax- the absence of these extreme (and hence obvious) fetal HR pat- ation and stasis throughout the biliary system.124 In the evaluation terns, interpretation of fetal tracings can be complex.132 There are of cholestasis or any liver disease, it is important to remember that no conclusive data to suggest that any single monitoring technique placental alkaline phosphatase can increase measured alkaline reflects fetal outcome.131 Optimization of maternal physiologic phosphatase levels by a factor of 3 or 4. status is more important than any mode of fetal monitoring. URINARY CHANGES RADIOLOGIC INVESTIGATION As cardiac output increases, the glomerular filtration rate X-rays and CT scans must be employed judiciously, given the increases by 30% to 50%.This increase reaches a peak at the end risk that radiation poses to the pregnant patient. Depending on of the first trimester. Accordingly, creatinine clearance and blood the exposure time and the total dose, radiation may cause failure urea nitrogen (BUN) levels fall by 25% over the first trimester. to implant, malformation, growth retardation, CNS abnormali- The kidneys themselves increase in size by 1.5 cm as a result of ties, or fetal loss. increased vascularity.125 The ureters become dilated as a conse- The standard units of measure for radiation are the Gray (Gy) quence of the relaxing effects of progesterone on smooth mus- and the rad; 1 Gy is equivalent to 100 rad, and 1 rad thus is equiv- cle.126 Dextrorotation of the uterus causes further dilatation of the alent to 1 cGy or 10 mGy. The ICRP has stated that radiation right ureter. doses lower than 100 mGy do not increase the risk of fetal death, malformation, or developmental delay.35 Doses between 200 to HEMATOLOGIC CHANGES 500 mGy during weeks 8 to 15 of gestation, however, result in Normal pregnancy causes numerous changes in coagulation measurable IQ reductions, and doses higher than 600 mGy result and fibrinolysis. Platelets become more reactive, and destruction in growth retardation and CNS damage. Most diagnostic proce- is enhanced; to compensate, the pregnant patient increases pro- dures fall within the accepted safe range. The average radiation duction of platelets. Normal pregnancy increases hepatic and dose from an abdominal x-ray is 1.4 mGy, that from an abdomi- endothelial cell synthesis of many procoagulant factors. Pregnant nal CT scan is 8.0 mGy, that from a pelvic CT scan is 25 mGy, women have normal anticoagulant factor levels except for a sharp and that from a selective spiral CT scan of the abdomen and the decrease in protein S antigen and activity. In general, fibrinolytic pelvis is 30 mGy. activity is impaired during pregnancy; however, bleeding time and In many instances, alternate diagnostic modalities that do not clotting time are unchanged. Overall, pregnancy is a hypercoagu- employ ionizing radiation, such as ultrasonography and MRI, are lable state.127 The risk of thromboembolism doubles during preg- sufficient to determine the proper treatment. If, however, diag- nancy.128 Accordingly, compression stockings should be used nostic radiation does prove necessary, the fetus should be shield- whenever surgical management is embarked on. ed, radiation exposure should be minimized, and radiation doses Leukocytosis is normally seen in pregnancy.What the net effect should be carefully documented.133 Careful cooperation with the of a decrease in CD4+ cells, an increase in CD8+ cells, and an radiologist will help limit radiation exposure. It is of particular unchanged number of B cells may be remains somewhat contro- importance that the patient be informed of the risks associated versial.129 More important than the higher total number of cells is with radiation in comparison with the expected benefits of diag- the altered activity exhibited by all leukocytes, a complicated pic- nostic radiation in her case. ture that is still not fully understood. ANESTHESIA Although pregnancy may appear to be an anemic state, it is not: blood volume actually increases (see above), and red cell mass The physiologic changes associated with pregnancy have impli- rises by 30% [see Table 2]. cations for anesthetic management. As noted (see above), oxygen reserve decreases with pregnancy. Upon intubation, hypoxia and hypercapnia with hypoventilation or apnea may develop rapidly. General Perioperative Considerations in Pregnant In one clinical study of obstetric anesthesia, airway difficulties Patients occurred in 7.9% of intubated patients, compared with 2.5% of The use of anesthesia in the course of an operation does not nonintubated patients134; it is noteworthy that the primary reasons pose a teratogenic risk to the fetus.130 Surgical treatment can be for difficult intubation were airway anatomy and technique, just as
  14. 14. © 2007 WebMD, Inc. All rights reserved. ACS Surgery: Principles and Practice 9 CARE IN SPECIAL SITUATIONS 3 THE PREGNANT SURGICAL PATIENT — 14 would be the case in nonpregnant patients. During intubation, phrine are also safe for use in pregnant women who are hypoten- pregnant women are also at increased risk for gastric aspiration sive [see Table 4]. owing to the decreased esophagogastric sphincter tone. Because of TIMING OF SURGERY this increased risk of aspiration, nasogastric suction should be freely employed. The stomach should be emptied before emer- If a surgical problem arises during pregnancy, the urgency of gency procedures and continually decompressed throughout the surgical treatment must be balanced against the risk such treat- operation and the early postoperative period. ment poses to the mother and the fetus. Urgent procedures, such Anesthesia can suppress the normal physiologic compensation as appendectomy, should be carried out in the usual timely fash- for aortocaval compression, in which event hypotension can ion [see Urgent Surgical Problems, above]: in such cases, the risks ensue. Positioning of the patient in a leftward tilt or the left lateral to both mother and fetus outweigh the risks of miscarriage and decubitus position can minimize hypotension.131 Liberal use of preterm labor. Semielective procedures are best done during the indwelling urinary catheters allows gross estimation of the ade- second trimester.76 In the first trimester, when organogenesis is quacy of blood volume and splanchnic perfusion during general ongoing, concerns arise about the teratogenic risks of medications operative procedures. If intra-abdominal operation is necessary and surgical interventions. During the first trimester, surgical pro- after weeks 12 to 16, the bladder must be decompressed to allow cedures are associated with a miscarriage rate of 12%; during the adequate exposure in the pelvis and the lower abdomen. second trimester, this rate falls to 0% to 5.6%. The incidence of According to retrospective studies, all anesthetic, opioid, seda- preterm labor with surgical procedures is 5% in the second tive-hypnotic, and anxiolytic agents pose some degree of risk to the trimester but rises to 30% to 40% in the third trimester.135 Elective fetus; none of them appears to be significantly more teratogenic or procedures should be delayed until 6 weeks after delivery. safer than any other.131 If vasopressors are necessary, ephedrine is TOCOLYTICS the drug of choice, in that it causes less uterine vasoconstriction than epinephrine or norepinephrine does. Small doses of phenyle- Even though surgical procedures have been associated with a Table 4—Safety of Various Drugs Used during Pregnancy177,178 Drug (FDA Pregnancy Toxicity Comments Category) Analgesics/tranquilizers Ibuprofen (B) Risk of postpartum hemorrhage; premature patent ductus arteriosus closure; no Use with caution toward end of pregnancy teratogenic effects Meperidine (B) Decreased neonatal respiration; CNS depression Greatest risk near term Morphine (C) Small size for gestational age; respiratory depression; fetal death Greatest risk near term Codeine (C) Possible congenital anomalies Avoid in first trimester Acetaminophen (B) None known Analgesic of choice Aspirin (C) Anticoagulation effect; fetal bleeding; possible prolongation of pregnancy; no Use with caution, especially toward end of pregnanc teratogenesis known not recommended for routine analgesia Barbiturates (C) Fetal addiction; neonatal bleeding; ?teratogenesis Long-term administration not recommended Diazepam (D) ?Cleft palate; ?heart defects; hypotonia; hypothermia; withdrawal symptoms Long-term administration not recommended Anesthetics Bupivacaine (C) Bradycardia Use with caution in late pregnancy Lidocaine (B) Bradycardia; CNS depression Use with caution in late pregnancy Halothane (C) Uterine relaxation Can cause abortion in early pregnancy Nitrous oxide ?Teratogenesis in early pregnancy Can be used in late pregnancy Muscle relaxants (C) Fetal curarization Relatively safe; incidence of problems extremely lo Antibiotics Ampicillin (B) None known Safe Aztreonam (B) Not teratogenic in rodents Safety in pregnancy unclear Cephalosporins (B) No embryocidal reports Safe Clindamycin (B) None known Safety in pregnancy unclear Erythromycin, Risk of cholestatic hepatitis; no reported congenital defects Avoid in pregnancy azithromycin (B) Fluoroquinolones (C) Irreversible arthropathy in immature animals Avoid in pregnancy Gentamicin (C) Possible 8th nerve toxicity; no reported congenital defects, neonatal ototoxicity, or Avoid in pregnancy nephrotoxicity Imipenem (C) None known Safety in pregnancy unclear Metronidazole (B) Carcinogenic in rodents; possibly teratogenic Contraindicated in first trimester; use with caution thereafter Nitrofurantoin (C) Hemolytic anemia in newborns; no known teratogenic effects Contraindicated at term Penicillin G (B) None known Safe Streptomycin (D) 8th cranial nerve abnormality Contraindicated Tetracycline (D) Adverse effects on fetal teeth and bones; maternal hepatotoxicity; congenital Contraindicated Trimethoprim- defects sulfamethoxazole (C) Hemolysis in G6PD-deficient patients; risk of kernicterus Contraindicated at term Vancomycin (C) Potential fetal ototoxicity, nephrotoxicity Avoid in pregnancy