CESAREAN DELIVERY

Question: Should we run the oxytocin “wide open” during a cesarean delivery?

Answer: While oxytocin is the most frequently used uterotonic agent in cesarean deliveries, large doses can lead to cardiovascular compromise or even collapse. Several safe dosing strategies for postpartum oxytocin infusion or administration exist. Tsen and colleagues have posited a “rule of threes” algorithm for administration of oxytocin that involves a 3 units intravenous loading dose, followed by additional 3 units rescue doses at 3 minute intervals for 3 total doses as needed; these initial loading doses should be followed by a maintenance infusion of oxytocin. This algorithm was validated in a randomized control trial that showed adequate uterine tone with lower doses of oxytocin in the rule of threes group vs. the standard group that received “wide open” oxytocin infusions; there were no differences in uterine tone or blood loss.

-Sharon Reale, MD
Brigham and Women’s Hospital, Boston, MA

References:
1. Tsen LC, Balki M. Oxytocin protocols during cesarean delivery: time to acknowledge the risk/benefit ratio? Int J Obstet Anesth 2010;19:243-5.
2. Kovacheva VP, Soens MA, Tsen LC. A Randomized, Double-blinded Trial of a “Rule of Threes” Algorithm versus Continuous Infusion of Oxytocin during Elective Cesarean Delivery. Anesthesiology 2015;123:92-100.

For More Information: 
1. Rule of threes algorithm

Question: Do we need to do left uterine displacement or tilt on all cesarean deliveries?

Answer: Current recommendations for left uterine displacement (LUD) in cesarean delivery include maintenance of the LUD until delivery of the fetus [1,2]. This basic principle is based on previous findings that the supine position increases aortocaval compression, maternal hypotension and fetal compromise [3]. In the supine position, the inferior vena cava is completely obstructed; however, most women experience limited hemodynamic change and are asymptomatic [4]. Clinically significant hemodynamic effects, also called “supine hypotensive syndrome,” is estimated to occur in 8 to 10% of women at term gestation [5].

A few modern studies have countered the standard recommendation for LUD in elective cesarean delivery. Lee, et al. [6] found that maternal supine position during elective cesarean delivery with spinal anesthesia in healthy term women does not impair neonatal acid-base status compared to a 15-degree left tilt. During the study, maternal systolic blood pressure was maintained with a co-load of fluid and phenylephrine infusion. However, these findings were limited to healthy pregnant women and should not be generalized to emergency situations or non-reassuring fetal status. The care team should also be aware that phenylephrine requirements were greater in those who were supine versus those with a 15-degree tilt.

- Michael H Wilhelm, DNP, CRNA, APRN
University of Connecticut/John Dempsey Hospital

References:
1. NICE, NIfHaCE: Clinical guidelines and updates: Caesarean section. Available at: https://www.nice.org.uk/guidance/cg132/chapter/1-guidance. Accessed November 16, 2018.
2. Practice guidelines for obstetric anesthesia: An updated report by the American Society of Anesthesiologists Task Force on Obstetric Anesthesia and the Society for Obstetric Anesthesia and Perinatology. Anesthesiology 2016; 124:270–300.
3. Higuchi, H, Takagi, S, Zhang, K, Furui, I, Ozaki, M : Effect of lateral tilt angle on the volume of the abdominal aorta and inferior vena cava in pregnant and nonpregnant women determined by magnetic resonance imaging. Anesthesiology 2015; 122:286–93.
4. Howard, BK, Goodson, JH, Mengert, WF : Supine hypotensive syndrome in late pregnancy. Obstet Gynecol 1953; 1:371–7.
5. Kinsella, SM, Lohmann, G : Supine hypotensive syndrome. Obstet Gynecol 1994; 83:774–88.
6. Lee AJ, et al. : Left Lateral Table Tilt for Elective Cesarean Delivery under Spinal Anesthesia Has No Effect on Neonatal Acid-Base Status: A Randomized Controlled Trial. Anesthesiology 2017; 127(2):241-249.

Question: Can I do spinal anesthesia for this patient with placenta previa for a cesarean section?

Answer: For scheduled, non-urgent cesarean delivery without profound vaginal bleeding and with a reassuring fetal status, a single shot spinal or other neuraxial anesthetic can be safely performed. If the patient had a bleeding episode recently, the patient should be adequately volume resuscitated prior to performing the neuraxial; clinical judgment should be used to determine if preoperative coagulation testing is needed to determine the safety of neuraxial anesthesia. If there is suspicion of a placenta accreta spectrum in a patient with previa (e.g. placenta previa in current pregnancy with known prior low-transverse cesarean scar), then excessive bleeding should be anticipated, and appropriate preparations made. In such cases, an epidural or a combined spinal-epidural may be performed to allow extension of surgical time, with selective conversion to general anesthetic if massive hemorrhage is encountered. Placenta previa in the absence of other risk factors is not a contraindication for neuraxial anesthesia for cesarean delivery.

-Sonal Zambare, MD
Baylor College of Medicine, Houston, TX

References:
1. Markley JC, Farber MK, Perlman NC, Carusi DA; Neuraxial anesthesia during Cesarean delivery for placenta previa with suspected morbidly adherent placenta: A Retrospective Analysis; Anesthesia and analgesia; VOL.:127, ISSUE: 4; 930-938
2. Berrin Günaydın, Mertihan Kurdoğlu, İsmail Güler, et al; Management of Neuraxial Anaesthesia for Emergent Caesarean Section for Placenta Previa; Turkish journal of anaesthesiology and reanimation; 2016; 44: 40-3

Question: Failed conversion of epidural catheter for surgical anesthesia for intrapartum cesarean delivery: Should I do a spinal?

Answer: The two major risks of placing a spinal after a failed epidural analgesia conversion to anesthesia, are 1) spinal failure due to presence of fluid in the epidural space that can be mistaken for CSF, and 2) the development of a high neuraxial block (HNB). 27% of HNB occur after a spinal technique following a failed epidural. Presence of fluid in the epidural space decreases the intrathecal (IT) volume therefore causing cephalad distribution of the local anesthetic. To minimize that risk, one approach can be to decrease the IT dose of local anesthetic and/or associate it with a catheter-based technique (epidural or CSE), to extend the duration of anesthesia if needed.

–Maria Cristina Gutierrez, MD
University of California Davis Medical Center

References:
1. D’Angelo R, Smiley RM, Riley ET, Segal S. Serious Complications Related to Obstetric Anesthesia: The Serious Complication Repository Project of the Society for Obstetric Anesthesia and Perinatology. Anesthesiology 2014;120(6):1505-1512.
2. Ginosar Y, Mirikatani E, Drover DR, Cohen SE, Riley ET. ED50and ED95of Intrathecal Hyperbaric Bupivacaine Coadministered with Opioids for Cesarean Delivery. Anesthesiology 2004;100(3):676-682.
3. Higuchi H, Takagi S, Onuki E, Fujita N, Ozaki M. Distribution of Epidural Saline Upon Injection and the Epidural Volume Effect in Pregnant Women. Anesthesiology 2011;114(5):1155-1161.