There are some contraindications to cesarean section which include; dead fetuses, except in the presence of an urgent maternal indication such as severe hemorrhage form a placenta previa; major fetal abnormality, incompatible with useful postnatal survival, if demonstrable in antenatal roentgenogram; eclamptic convulsions, until controlled by medical theraphy; infection in the abdominal wall or peritoneal cavity. Cesarean sections performed before the onset of labor, other than those dictated by a obstetrical emergency, are known as elective.
Repeat sections, for patientswith a previous section or myomectomy, fall in this category and are usually perfomed one to two weeks before the expected date of labor. In case of maternal diabetes, pregnancy toxemia, or isoimmunization to the Rh or other blood factors, cesarean section may be elected as much as a month before term, depending upon specific factors in each case. The principal pitfall in elective cesarean section is the uncertainty in predicting the size and maturity of the fetus. A gross overestimate may result in the delivery of a premature fetus with its associated hazards.
The calculated date of confinement may be in error as a result of the patient’s faulty recollection of her last menstrual date or because of menstrual irregularity or amenorrhea preceding conception. Also, abdominal palpation may lead to an overestimate of fetal weight, especially if the patient is obese, has polyhydramnios, a breech presentation or a multiple pregnancy. Sterile vaginal examination before a contemplated elective section may provide an indication of approaching term if the cervix is found partially effaced and slightly dilated, but this may also be misleading in the presence of polyhydramnios or multiple pregnancy.
Additional evidence of fetal size and maturity can be obtained from a roentgenogram, which often permits measurement of the diameters and circumference of the fetal skull. More significant, however, as a criterion of fetal viability, is the appearance of the ossification center in the distal epiphysis of the femur. This ossification center is resent in about 80 percent of fetuses weighing between 2000 grams ad 2500 grams and in 90 percent of fetuses over 2500 grams.
Ossification at the proximal tibial epiphysis, a well cacified fetal skull, and a good subcutaneous fat line are additional signs of fetal maturity. If continuation of pregnancy to term carries no increased risk to mother or fetus, as in cases of contracted pelvis with anticipated disproportion, it is preferable not to perform elective cesarean section but to await the onset of labor. This policy has 2 advantages; it frequently eliminates the need for cesarean section by demonstrating the feasibility of vaginal delivery, and also reduces the fetal risk of premature delivery.
Once the necessity for cesarean section has been established, the operation should be carried out as soon as possible after labor begins. If the membranes have been ruptured for more than 10 hours or the patient has had recent multiple vaginal examinations, prophylactic treatment with antibiotics should be started prior to operation. If elective cesarean section is contemplated, the patient should be admitted to the hospital the day before, and in addition to routine physical examination, blood count, and urinalysis, 500 to 1000 cc of compatible blood should be reserved for transfusion.
If the hemoglobin concentration is less than 10 grams per 100 cc, a transfusion should be given preparatory to operation. The abdomen and perineum are shaved. The patient is given a light supper and a sedative to ensure a good night’s sleep. Nothing further is permitted by mouth prior to operation the following day. An enema is given about 2 hours before operation. Preoperative medication is kept at a minimum to avoid depression to the infant. Demerol 50 mg and scopolamine or atropine 0. 3 mg, 30 to 45 minutes before operation, usually suffices
The choice of anesthetic is subject to many variables. Including the medical and physiological condition of the patient, preference of the operator and skill and experience of the anesthetist. The safest anesthetic is local infiltration (with Procaine 0. 5 percent or 1 percent). This may be supplemented with intravenous sodium Pentothal or an inhalation anesthetic, if desired, just before the uterus is incised or after the baby is delivered. Spinal anesthesia for cesarean section has achieved popularity during the past decade.
Both it and local infiltration have the important advantage of avoiding respiratory depression in the fetus and are particularly indicated, therefore, in repeat sections and for patients with previous pelvic operations, in whom intra-abdominal adhesions may delay exposure and incision of the uterus. When a general anesthetic is used, whether inhalation or intravenous, time is of the essence, and delivery of the infant should be carried out with the greatest dispatch consistent with safe surgical technique.
Therefore, the patient should be catheterized, positioned on the operating table, and her abdomen suitably prepared with an antiseptic solution and draped before the induction of anesthesia is begun. A slow intravenous infusion of 5 percent glucose solution should be started preoperatively, to facilitate the later administration of fluids or blood if necessary. In addition to the operating team, an assistant should be in attendance to receive the newborn infant and perform any necessary resuscitative measures, including aspiration of the nasopharynx and stomach and administration of oxygen.
Technique. With the patient in a mild Trendelenburg position, the abdomen is opened through either a midline incision between pubis and umbilicus or a transverse (Pfannestiel) incision. If local infiltration anesthesia is used, there is usually little bleeding from the skin edges. Clamps for the control of bleeding points are not replaced with ties until closure of the abdominal incision, in order to avoid delay in the delivery of the fetus.
The abdominal wall is usually attenuated but edematous in late pregnancy. A small amount of straw-colored fluid may be present in the peritoneal cavity; this has no significance. After exposing the uterus, the operator should feel for the round ligaments and manually correct any dextrorotation. It is usually unnecessary to insert any packs into the peritoneal cavity before the uterus is emptied, since the latter fills the incision and keeps the intestines out of the operative field unless the patient strains.
Incision of the uterus is of 2 principal types, fundal or classical and lower segment or low cervical. The latter may be either transverse or longitudinal. Classical cesarean section is a somewhat simpler operation and permits extraction of the infant more rapidly than the lower segment approach. The classical incision is therefore indicated in emergencies that require speedy action, such as fetal distress resulting from prolapse of the umbilical cord.
Some prefer the classical approach in cases of placenta previa, to avoid cutting through the placental site; but other obstetricians deliberately choose the lower segment incision in such cases because of the opportunity it provides for the suturing of bleeding sinuses, The classical incision is preferable in cases of transverse lie with shoulder presentation, because of the advantage in this incision offers in extracting a fetus lying entirely within the fundal portion of the uterus, Its extraction through a lower segment incision may be exceedingly difficult.
The chief disadvantages of the classical incision are; the scar is probably more prone to rupture in subsequent pregnancies than lower segment scars; it is more favorable to the formation of adhesions between the uterus and anterior parietal peritoneum, omentum, and small bowel. Temporary abdominal distention and actual intestinal obstruction are therefore more common postoperative complications than after the lower segment operation; and lastly, it permits a less effective seal between the uterine and peritoneal cavities, thereby increasing the danger of peritonitis in cases of puerperal infection.
Classical cesarean section is therefore contraindicated in the presence of intrapartum fever, ruptured membranes for more than 10 hours, and in patients with well-established labr or those who have had multiple vaginal or rectal examinations within the preceding 24 hours. In these situations, the lower segment operation is far safer but should be preceded by antibiotic therapy nevertheless. The classical incision is made longitudinally in the midline of the anterior surface of the fundus, ending just above the bladder reflection.
When the membranes are reached or punctured, the incision is extended in both directions to the necessary length of approximately 12 cm by means of a bandage scissors, the operator advancing the index and middle fingers of his free hand inside the uterus ahead of the scissors blade to protect the fetus and umbilical cord from injury. The membranes, if still intact, are now punctured. If the placenta is anterior and underlies the incision the operator should either insinuate his hand upward between the placenta and the membranes to get to the fetus or else cut through the placenta with haste to avoid unnecessary loss of blood.
If it is necessary to cut or tear the placenta to extract the fetus, the cord should be pinched and clamped as quickly as possible to minimize the loss of fetal blood through the severed placental vessels. The operator then reaches up into the fundus of the uterus, grasps one or both legs, brings them out through the incision, and extracts the fetus by the breech. Care must be taken not to confuse the feet with the hands in performing the extraction. The cord is now cut between 2 clamps and the baby passed to the sterile garbed assistant prepared to aspirate and if necessary resuscitate the newborn.
The placenta with its attached membranes are peeled manually off the uterine wall; adherent fragments should be grasp with a clamp and pulled or twisted loosed or wiped away with a gauze pad. An assistant should inspect the maternal surface of the placenta for defects, indicating the retention of cotyledons within the uterus. Uterine contraction is augmented by oxytocic drugs at this time. Pitocin 1 cc is given intramuscularly or intravenously, or Ergotrate 1 cc by the former route.
We prefer not to give Ergotrate intravenously because of the occasional marked elevation of blood pressure it may cause and in conscious patients, vomiting. Some obstetricians prefer to inject the oxytocic agent directly into the myometrium at cesarean section, but this method seems illogical. Part of the drug injected into the uterus is washed out by the venous flow into the wound; the rest, to effectively stimulate the entire myometrium, must first be absorbed into the systemic channels and then recirculate to the uterus.
We therefore have the oxytocic injected into an arm or leg by the anesthesist or nurse. If a spinal or caudal anesthetic is used, injection into the leg or buttock avoids patient discomfort. If there is any tendency for the uterus to relax, we also add 1 cc of Pitocin to the intravenous infusion of glucose solution or blood. It is unnecessary to dilate the cervix to promote uterine drainage, even if the patient has not been in labor and the canal is closed.