Cesarean Delivery



Cesarean Delivery


Samantha Do

Kimberly Harney

Michael A. Belfort

Yasser El-Sayed



GENERAL PRINCIPLES



Physical Examination



  • Heart and lung examination


  • Abdominal examination focusing on the following:



    • Prior abdominal incisions and scars, alerting the surgeon to prior surgeries or trauma with risk of intra-abdominal adhesions


    • Distribution of adiposity in obese patients that may also influence the choice of abdominal entry


  • Assessment of head, neck, and airway performed by anesthesiologist in case general anesthesia is anticipated or becomes required


Nonoperative Management



  • The rate of CD rapidly increased from 1996 to 2011, prompting the publication of recommendations from professional societies with strategies to prevent primary CD. Acknowledging that some conditions such as placenta previa, accreta, and history of uterine rupture are absolute contraindications to vaginal delivery, the recommendations target other indications for CD where alterative management may allow for a safe vaginal delivery.


  • Analysis of modern labor progress showed that rates of cervical change may be slower than that suggested by the classic Friedman labor curve and that epidural anesthesia significantly prolongs duration of pushing. Definitions of arrest of labor in the first and second stages were thus updated in 2014 to reflect contemporary labor curves and allow more time before diagnosing an arrest of labor (1).



    • CD is only indicated for arrest of dilation for patients at or beyond 6 cm of dilation with ruptured membranes and 4 hours of adequate uterine contractions or 6 hours of oxytocin with inadequate uterine contractions and no cervical change.


    • In the setting of reassuring maternal status and fetal monitoring, multiparous patients should be allowed to push for 2 hours and nulliparous patients for 3 hours, with longer durations appropriate with epidural anesthesia or fetal malposition as long as progress is documented. The benefit of vaginal delivery must be weighed against the increased morbidity of CD after extended duration of pushing, with potential for increased maternal and neonatal morbidity with CD for arrest seen since implementation of the new labor management guidelines (2).


  • Other strategies to prevent CD because of arrest of descent include manual rotation of the fetal occiput in cases of fetal malposition and operative vaginal delivery. Operative vaginal delivery with vacuum or forceps for prolonged second stage, fetal compromise, or maternal medical disorders is considered a safe alternative to CD when performed by well-trained physicians for appropriate candidates.


  • With induction of labor and reassuring maternal and fetal status, CD may be avoided by not diagnosing a failed induction of labor until at least 12 to 18 hours of oxytocin administration after membrane rupture. In addition, with induction of labor and an unfavorable cervix, cervical ripening increases the likelihood of vaginal delivery.


  • Amnioinfusion in women with repetitive variable decelerations possibly due to cord compression decreases the rate of CD without worsening neonatal outcomes.


  • For noncephalic singleton fetuses, patients without contraindications should be offered an external cephalic version as an alternative to CD. The external cephalic version decreases the rate of primary CD.


  • Planned vaginal delivery is a safe alternative to planned CD for twin gestations, with appropriate concordance in weight, with the presenting fetus vertex at or after 32 weeks regardless of position of second twin, with an obstetrician experienced in vaginal breech delivery.


  • The preceding strategies target decreasing the rate of primary CD. Trial of labor after cesarean (TOLAC) is an alternative to elective repeat CD. Because failed TOLAC confers higher morbidity than does an elective repeat CD, assessing the likelihood of successful TOLAC is important for counseling patients and selecting optimal candidates. Women with a high likelihood of successful TOLAC and low risk of uterine rupture (prior low transverse uterine incision, one prior CD) are the best candidates. TOLAC should be performed in hospitals where emergency CD is available.


IMAGING AND OTHER DIAGNOSTICS



  • Perform bedside ultrasound to assess fetal presentation before nonlabored CD. Particularly with a transverse lie, assessing if the fetus is back up or back down may influence hysterotomy choice and delivery of the fetus. Ultrasound to assess placental location may allow the surgeon to avoid disturbing the placenta at hysterotomy.


  • Brief ultrasound before second-stage CD confirms fetal position to optimize head flexion at delivery and to evaluate location of limbs in case reverse breech delivery is required with an impacted head.


  • Fetal heart monitoring with a nonstress test before scheduled CD establishes fetal status before delivery. Monitoring may be discontinued after the nonstress test if the tracing is reactive and reassuring. For laboring patients, fetal heart monitoring should continue in the operating room (OR).


  • Laboratory testing for complete blood count and blood type is recommended to assess starting hemoglobin level and platelet count before placement of neuraxial anesthesia. For women at moderate risk for hemorrhage (postpartum hemorrhage [PPH]), perform a type and screen. For women at high risk for PPH, type and crossmatching is advised.


  • Women with congenital uterine anomalies require imaging of the urologic tract because 20% to 30% of those with Müllerian defects will have renal anomalies. Screen women during pregnancy with renal ultrasound if no prior imaging has been done. Unrecognized abnormal renal system anatomy may increase the risk of ureteral injury during CD.


PREOPERATIVE PLANNING



  • Evidenced-based perioperative interventions for CD have been studied and a recently published Enhanced Recovery After Surgery (ERAS) protocol provides preoperative recommendations to reduce surgical morbidity (3).




    • Preoperative administration of antacids to neutralize gastric acid and histamine H2 receptor antagonists to prevent low gastric pH may reduce the risk of aspiration pneumonitis in women undergoing CD under general anesthesia. Because some women undergoing CD with regional anesthesia require conversion to general, the ERAS guideline recommends antacids and H2 antagonists for all CD; however, the evidence for this recommendation is low.


    • Previously, patients were counseled to have nothing to eat or drink after midnight before CD. Updated guidelines reflect evidence extrapolated to CD from other surgeries that showed no increase in complications with shorter durations of preoperative fasting. ERAS recommends clear liquids until 2 hours before CD and a light meal may be eaten up to 6 hours before CD.


    • Antibiotic administration with a first-generation cephalosporin in the 60 minutes before skin incision decreases the risk of postoperative infections. Women in labor or with ruptured membranes are at higher risk for infection and benefit from the addition of azithromycin.


    • Abdominal skin preparation with chlorhexidine-alcohol scrub is recommended on the basis of a randomized trial that showed decreased surgical site infections compared with povidone-iodine solution (4).


    • Vaginal preparation with povidone-iodine solution appears to decrease the risk of endometritis for CD performed in labor or after rupture of membranes.


  • CD increases the risk of venous thromboembolism (VTE) compared to vaginal delivery. For women at low risk for VTE, sequential compression devices during CD provide mechanical prophylaxis. On the basis of individual risk factors (history of VTE, thrombophilia, body mass index [BMI]), some women may require pharmacologic VTE prophylaxis following CD.


  • Depending on individual hospital factors and clinical situation, it may be beneficial to have red blood cells, fresh frozen plasma, and platelets in the OR before commencing CD for patients at high risk for PPH such as placenta previa unless blood products can be rapidly sent to the OR as in institutions with a massive transfusion protocol.


  • Maternal comorbidities, particularly cardiovascular, need to be assessed before CD. For women with high-risk cardiac conditions such as pulmonary hypertension or significant aortic dilation, planning for delivery includes determining safety of medications, hemodynamic monitoring requirements, delivery location, and postpartum recovery location.


  • All women require a preoperative consultation with an anesthesiologist before CD. For women with medical or obstetric (OB) issues that place them at elevated risk with CD, anesthesia consultation should occur before admission. For women without elevated risk, consultation may occur on the day of surgery.



    • Neuraxial anesthesia is generally preferred because it allows the mother to be awake for the delivery, facilitates postoperative pain control, and minimizes maternal morbidity, systemic administration of opioids, and transfer of medication to the fetus.


    • General anesthesia may be required when there is a maternal contraindication to neuraxial or failed or inadequate neuraxial block.


    • General anesthesia may also be required for emergency CD with insufficient time to place neuraxial anesthesia or reach a surgical level by bolusing a labor epidural catheter. With emergency CD, it is critical for OB and anesthesia providers to communicate about the urgency of the case to establish the best anesthetic technique for the situation.


  • Repeat CD is planned for the 39th week of gestation for women electing for a repeat CD with prior low transverse incision in the absence of OB or medical indications requiring earlier delivery. Planned repeat CD at 39 weeks allows for optimal fetal maturation and balances the risk of neonatal respiratory morbidity from early delivery with the risk of uterine rupture due to labor.



    • For women with a prior classic incision, repeat CD is recommended between 36+0 and 37+0 weeks. As a prior classic scar has a high risk of rupture with labor, the goal is to perform repeat CD in stable patients before the onset of labor while balancing risk of uterine rupture against risks of prematurity.


SURGICAL MANAGEMENT



  • The most common indications for primary CD are failure to progress during labor, nonreassuring fetal status, and fetal malpresentation.


  • Other indications include history of prior CD or uterine surgery, placenta previa, accreta, vasa previa, cord prolapse or funic presentation, mechanical obstruction to vaginal birth, uterine rupture, multiple gestation, suspected fetal macrosomia, selected fetal conditions, selected maternal comorbidities, and maternal request.


Positioning



  • CD is usually performed in the dorsal supine position with a left lateral tilt to reduce aortocaval compression.


  • For CD for arrest of descent, a low dorsal lithotomy position may facilitate delivery of an impacted fetal head. Placing the patient’s legs in stirrups allows for improved ergonomics to elevate the head vaginally and may open the pelvis and facilitate ongoing evaluation of vaginal bleeding. Placing the patient in low lithotomy allows the obstetrician to assess for the risk of head impaction with a test lift before scrubbing for CD. Trendelenburg may also optimize delivery with an impacted head.


Approach



  • Preoperative education is important for women planning CD and for women planning vaginal delivery because almost one-third of primiparous women undergo CD.


  • Providing antenatal education and counseling allows patients to make an informed choice when CD is recommended and helps set expectations for postoperative recovery.

Sep 9, 2022 | Posted by in OBSTETRICS | Comments Off on Cesarean Delivery
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