The second trimester is generally the safest time to intervene because there is a higher incidence of preterm labor in the third trimester and spontaneous abortion during the first trimester. The incidence of miscarriage after surgery in the second trimester is 5.6%, compared with 12% in the first trimester.
Ideally, pre-, intra-, and postoperative management should be planned through multispecialty discussion involving anesthesiologists, general surgeons, and gynecologic surgeons.
Preanesthetic medications include benzodiazepines (for example, midazolam) and/or opioids (such as Fentanyl administered intravenously). Intravenous induction agents include propofol, barbiturates, ketamine, and etomidate (Arch. Gynecol. Obstet. 2007;276:201–9). Neuromuscular blocking medications include succinylcholine, vecuronium, or atracurium complemented by the administration of nitrous oxide.
Operative Management
Patient positioning during surgery is critical. The pregnant patient should be placed in the left lateral decubitus position, with her right hip elevated, to minimize interference with venous return. She must also undergo a more gradual, careful change to the Trendelenburg position than a nonpregnant patient would, and even more gradual reverse Trendelenburg positional changes.
Intraoperative monitoring should include measurement of vital signs, oxygen saturation, and end-tidal CO2 level, and observation of uterine activity. Intraabdominal pressure generally should be in the range of 12–15 mm Hg. Ideally, lower-extremity pneumatic compression devices should be utilized.
Careful monitoring for signs of preterm labor is also important. Fetal heart rate monitoring can provide useful data, both preoperatively and postoperatively. The use of tocolytic agents is certainly indicated when there are signs of preterm labor, but there is minimal support among experts for routine prophylactic tocolysis in the second trimester. Depending on the clinical circumstance, at 24 weeks' gestation, tocolysis can be considered.
Experts have debated for years the gestational age at which the uterus limits laparoscopic access to the abdominal cavity, and there still is no consensus.
Controversy continues over the use of the open laparoscopic technique versus the use of the Veress needle traditional technique (closed), especially in the left upper quadrant. Researchers are also investigating the use of gasless laparoscopy during pregnancy.
The vast majority of gynecologic and general surgeons who perform laparoscopic surgery in pregnant patients lean toward an open laparoscopic technique, but the closed and gasless techniques are also acceptable. I favor the primary use of an open approach with the Hasson cannula. This often provides better overall control with regard to entrance into the peritoneal cavity.
Clinicians who opt to use a Veress needle are certainly focused on an acceptable alternative to introduction of CO2 into the peritoneal cavity. The decision-making process is primarily a reflection of the gynecologic surgeon's training and level of comfort.
We should strive to avoid placing any instruments near the cervix. A sponge on a stick can provide an element of uterine manipulation in an atraumatic manner.
Secondary trocar placement must take into account the size of the uterus, with secondary trocar sleeves placed above the umbilicus and away from the uterus. Careful planning of where ports should be placed is a wise idea prior to making the skin incision. Inferior epigastric vessels should be identified to include superficial branches.
Direct visualization of trocar entrance into the abdominal cavity is of paramount importance and should be documented in the record accordingly.
Prompt Diagnosis
Associated morbidity makes a prompt diagnosis of acute appendicitis or cholecystitis critical. As obstetricians we should be well versed in the various symptoms and clinical presentation of these problems in pregnant patients. We must have a high index of suspicion and be ready to engage a general surgeon colleague early on.
A diagnosis of appendicitis can all too easily be delayed because of the displacement of the appendix by the gravid uterus and the normal physiological leukocytosis of pregnancy. The consequences of delay, however, are significant: The incidence of fetal loss is as high as 35% when the appendix ruptures, compared with 1.5% with uncomplicated appendicitis.
The appendix changes location during gestation, rising progressively above the McBurney point. At 8 or 9 months, the appendix can essentially be as high as the top of the uterine fundus. As an inflamed appendix drifts away from the abdominal wall, the signs of peritoneal irritation are often minimized; fewer than half of pregnant patients, in fact, have peritoneal signs.
During the first trimester, the pain is primarily in the area of the McBurney point, and sometimes in the pelvic area. In the second trimester, the pain is associated with the displacement of the appendix, with the point of maximal tenderness frequently above the iliac crest. In the third trimester, pain and tenderness may be localized to the right costal margin. Irrespective of the trimester, patients often have right lateral rectal tenderness.