Continuation of the Pregnancy

Continuation of the Pregnancy

Surgery during pregnancy is associated with a higher incidence of premature labor and spontaneous abortion. The incidence is higher in lower abdominal, pelvic, and cervical surgery. Tocolytic drugs, both for prophylactic and therapeutic reasons, are used quite often to prevent premature delivery.

General and Specific Recommendations

Elective surgery should be postponed until delivery. In semi elective cases, it is best if surgery can be postponed until after the first trimester. In emergency cases, the anesthetic of choice should depend on the site and extent of the surgery to be performed. If possible, regional anesthesia, e.g., spinal,epidural, or nerve block, is advisable. However, general anesthesia can be administered if necessary. Preoperative medications, if necessary, may include barbiturates and morphine. Routine, non particulate antacid should be used, and rapid-sequence induction is recommended.

Although there is no general consensus, it is reasonable to use an endotracheal tube from the 12th week of gestation onward. Depending on the duration of surgery, one can use either depolarizing or non depolarizing muscle relaxants. Anesthesia can be maintained with nitrous oxide, oxygen, and halogenated anesthetics. Morphine, fentanyl, sufentanil, or alfentanil can be used as analgesics. Hyperventilation should always be avoided because it can reduce utero-placental perfusion as well as shift the maternal hemoglobin dissociation curve to the left.

For regional anesthesia, maintenance of normal blood pressure is absolutely necessary, and the routine use of oxygen by face mask is recommended. Whether general or regional anes thesia has been chosen, left uterine displacement from the second trimester onward is mandatory.

Routine monitoring should include blood pressure, electrocardiogram, oxygen saturation, capnograph, and temperature. In addition, fetal heart rate monitoring, if possible, should be performed from 16 weeks onward. Close communication between the anesthesiologist and obstetrician regarding fetal heart rate monitoring is necessary as well as interpretation of the tracings. Because most of the medications used for general anesthesia can abolish the fetal heart rate variability, the baseline fetal heart rate should be the main indicator of fetal wellbeing during general anesthesia. Depending upon the location of surgery, tocodynamometry can be used to monitor uterine contractions. This obviously becomes routine in the postoperative period when treating pregnant women with preterm contractions with tocolytics. Recently, laparoscopic surgery during pregnancy has been used with success. One must have a basic knowledge of physiological changes during pregnancy. During laparoscopic cholecystectomy, the women are placed in a head-up position during dissection and in a head-down position for irrigation. In parturients, these positions may have significant cardiovascular and respiratory effects.

Peritoneal insufflation pressure should be kept low because of the possibility of aortocaval compression. Ventilation should be optimal to maintain end-tidal PCO2 at 32-35mmHg

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