Practice guidelines for Obstetric Anesthesia 2016

Obstetric anesthesia refers to peripartum anesthetic and analgesic activities performed during labor and vaginal delivery, cesarean delivery, removal of retained placenta, and postpartum tubal ligation.

In February 2016, American Society of Anesthesiologists Task Force on Obstetric Anesthesia and the Society for Obstetric Anesthesia and Perinatology updated guidelines on obstetric anesthesia. Following are its major recommendations:-

Perianesthetic Evaluation and Preparation

History and Physical Examination

• Conduct a focused history and physical examination before providing anesthesia care.
  
  
  
  • This should include, but is not limited to, a maternal health and anesthetic history, a relevant obstetric history, a baseline blood pressure measurement, and an airway, heart, and lung examination
  
  
  • When a neuraxial anesthetic is planned or placed, examine the patient's back.
  
  
  • Recognition of significant anesthetic or obstetric risk factors should encourage consultation between the obstetrician and the anesthesiologist.
  
  
  
  


• A communication system should be in place to encourage the early and ongoing contact between obstetric providers, anesthesiologists, and other members of the multidisciplinary team.

Intrapartum Platelet Count

• The anesthesiologist's decision to order or require a platelet count should be individualized and based on a patient's history (e.g., preeclampsia with severe features), physical examination, and clinical signs.*
  
  
  
  • A routine platelet count is not necessary in the healthy parturient.
  
  
  
  

*A specific platelet count predictive of neuraxial anesthetic complications has not been determined.

Blood Type and Screen

• A routine blood cross-match is not necessary for healthy and uncomplicated parturients for vaginal or operative delivery.


• The decision whether to order or require a blood type and screen or cross-match should be based on maternal history, anticipated hemorrhagic complications (e.g., placenta accreta in a patient with placenta previa and previous uterine surgery), and local institutional policies.

Perianesthetic Recording of Fetal Heart Rate Patterns

• Fetal heart rate patterns should be monitored by a qualified individual before and after administration of neuraxial analgesia for labor.


• Continuous electronic recording of fetal heart rate patterns may not be necessary in every clinical setting and may not be possible during placement of a neuraxial catheter.†

†American College of Obstetricians and Gynecologists: ACOG Practice Bulletin No. 106: Intrapartum fetal heart rate monitoring: Nomenclature, interpretation, and general management principles. Obstet Gynecol 2009; 114:192–202.

Aspiration Prevention

Clear Liquids

• The oral intake of moderate amounts of clear liquids may be allowed for uncomplicated laboring patients.


• The uncomplicated patient undergoing elective surgery may have clear liquids up to 2 h before induction of anesthesia.
  
  
  
  • Examples of clear liquids include, but are not limited to, water, fruit juices without pulp, carbonated beverages, clear tea, black coffee, and sports drinks.
  
  
  • The volume of liquid ingested is less important than the presence of particulate matter in the liquid ingested.
  
  
  
  


• Laboring patients with additional risk factors for aspiration (e.g., morbid obesity, diabetes mellitus, and difficult airway) or patients at increased risk for operative delivery (e.g., nonreassuring fetal heart rate pattern) may have further restrictions of oral intake, determined on a case-by-case basis.

Solids

• Solid foods should be avoided in laboring patients.


• The patient undergoing elective surgery (e.g., scheduled cesarean delivery or postpartum tubal ligation) should undergo a fasting period for solids of 6 to 8 h depending on the type of food ingested (e.g., fat content)

Antacids, H₂-receptor Antagonists, and Metoclopramide

• Before surgical procedures (e.g., cesarean delivery and postpartum tubal ligation), consider the timely administration of nonparticulate antacids, histamine (H₂₎ receptor antagonists, and/or metoclopramide for aspiration prophylaxis.

Anesthetic Care for Labor and Vaginal Delivery

Timing of Neuraxial Analgesia and Outcome of Labor

• Provide patients in early labor (i.e., less than 5 cm dilation) the option of neuraxial analgesia when this service is available.


• Offer neuraxial analgesia on an individualized basis regardless of cervical dilation.
  
  
  
  • Reassure patients that the use of neuraxial analgesia does not increase the incidence of cesarean delivery.
  
  
  
  

Neuraxial Analgesia and Trial of Labor after Prior Cesarean Delivery

• Offer neuraxial techniques to patients attempting vaginal birth after previous cesarean delivery.


• For these patients, consider early placement of a neuraxial catheter that can be used later for labor analgesia or for anesthesia in the event of operative delivery.

Analgesia/Anesthetic Techniques

Early Insertion of a Neuraxial (i.e., Spinal or Epidural) Catheter for Complicated Parturients

• Consider early insertion of a neuraxial catheter for obstetric (e.g., twin gestation or preeclampsia) or anesthetic indications (e.g., anticipated difficult airway or obesity) to reduce the need for general anesthesia if an emergent procedure becomes necessary.
  
  
  
  • In these cases, the insertion of a neuraxial catheter may precede the onset of labor or a patient's request for labor analgesia.
  
  
  
  

Continuous Infusion Epidural Analgesia

• Continuous epidural infusion may be used for effective analgesia for labor and delivery.


• When a continuous epidural infusion of local anesthetic is selected, an opioid may be added to reduce the concentration of local anesthetic, improve the quality of analgesia, and minimize motor block.

Analgesic Concentrations

• Use dilute concentrations of local anesthetics with opioids to produce as little motor block as possible.

Single-injection Spinal Opioids with or without Local Anesthetics

• Single-injection spinal opioids with or without local anesthetics may be used to provide effective, although time-limited, analgesia for labor when spontaneous vaginal delivery is anticipated.


• If labor duration is anticipated to be longer than the analgesic effects of the spinal drugs chosen, or if there is a reasonable possibility of operative delivery, then consider a catheter technique instead of a single-injection technique.


• A local anesthetic may be added to a spinal opioid to increase duration and improve quality of analgesia.

Pencil-point Spinal Needles

• Use pencil-point spinal needles instead of cutting-bevel spinal needles to minimize the risk of postdural puncture headache.

Combined Spinal–Epidural Analgesia

• If labor duration is anticipated to be longer than the analgesic effects of the spinal drugs chosen, or if there is a reasonable possibility of operative delivery, then consider a catheter technique instead of a single-injection technique.


• Combined spinal–epidural techniques may be used to provide effective and rapid onset of analgesia for labor.

Patient-controlled Epidural Analgesia (PCEA)

• PCEA may be used to provide an effective and flexible approach for the maintenance of labor analgesia.


• The use of PCEA may be preferable to fixed-rate continuous infusion epidural analgesia for administering reduced dosages of local anesthetics.


• PCEA may be used with or without a background infusion.

Removal of Retained Placenta

Anesthetic Techniques

• In general, there is no preferred anesthetic technique for removal of retained placenta.
  
  
  
  • If an epidural catheter is in place and the patient is hemodynamically stable, consider providing epidural anesthesia.
  
  
  
  


• Assess hemodynamic status before administering neuraxial anesthesia.


• Consider aspiration prophylaxis.


• Titrate sedation/analgesia carefully due to the potential risks of respiratory depression and pulmonary aspiration during the immediate postpartum period.


• In cases involving major maternal hemorrhage with hemodynamic instability, general anesthesia with an endotracheal tube may be considered in preference to neuraxial anesthesia.

Nitroglycerin for Uterine Relaxation

• Nitroglycerin may be used as an alternative to terbutaline sulfate or general endotracheal anesthesia with halogenated agents for uterine relaxation during removal of retained placental tissue.
  
  
  
  • Initiating treatment with incremental doses of intravenous (IV) or sublingual (i.e., tablet or metered dose spray) nitroglycerin may be done to sufficiently relax the uterus.
  
  
  
  

Anesthetic Care for Cesarean Delivery

Equipment, Facilities, and Support Personnel

• Equipment, facilities, and support personnel available in the labor and delivery operating suite should be comparable to those available in the main operating suite.


• Resources for the treatment of potential complications (e.g., failed intubation, inadequate analgesia/anesthesia, hypotension, respiratory depression, local anesthetic systemic toxicity, pruritus, and vomiting) should also be available in the labor and delivery operating suite.


• Appropriate equipment and personnel should be available to care for obstetric patients recovering from neuraxial or general anesthesia.

General, Epidural, Spinal, or Combined Spinal–Epidural Anesthesia

• The decision to use a particular anesthetic technique for cesarean delivery should be individualized, based on anesthetic, obstetric, or fetal risk factors (e.g., elective vs. emergency), the preferences of the patient, and the judgment of the anesthesiologist.
  
  
  
  • Uterine displacement (usually left displacement) should be maintained until delivery regardless of the anesthetic technique used.
  
  
  
  


• Consider selecting neuraxial techniques in preference to general anesthesia for most cesarean deliveries.


• If spinal anesthesia is chosen, use pencil-point spinal needles instead of cutting-bevel spinal needles.


• For urgent cesarean delivery, an indwelling epidural catheter may be used as an alternative to initiation of spinal or general anesthesia.


• General anesthesia may be the most appropriate choice in some circumstances (e.g., profound fetal bradycardia, ruptured uterus, severe hemorrhage, severe placental abruption, umbilical cord prolapse, and preterm footling breech).

IV Fluid Preloading or Coloading

• IV fluid preloading or coloading may be used to reduce the frequency of maternal hypotension after spinal anesthesia for cesarean delivery.


• Do not delay the initiation of spinal anesthesia in order to administer a fixed volume of IV fluid.

Ephedrine or Phenylephrine

• Either IV ephedrine or phenylephrine may be used for treating hypotension during neuraxial anesthesia.


• In the absence of maternal bradycardia, consider selecting phenylephrine because of improved fetal acid–base status in uncomplicated pregnancies.

Neuraxial Opioids for Postoperative Analgesia

• For postoperative analgesia after neuraxial anesthesia for cesarean delivery, consider selecting neuraxial opioids rather than intermittent injections of parenteral opioids.

Postpartum Tubal Ligation

• Before a postpartum tubal ligation, the patient should have no oral intake of solid foods within 6 to 8 h of the surgery, depending on the type of food ingested (e.g., fat content) .


• Consider aspiration prophylaxis.


• Both the timing of the procedure and the decision to use a particular anesthetic technique (i.e., neuraxial vs. general) should be individualized, based on anesthetic and obstetric risk factors (e.g., blood loss) and patient preferences.


• Consider selecting neuraxial techniques in preference to general anesthesia for most postpartum tubal ligations.
  
  
  
  • Be aware that gastric emptying will be delayed in patients who have received opioids during labor.
  
  
  • Be aware that an epidural catheter placed for labor may be more likely to fail with longer post-delivery time intervals.
  
  
  • If a postpartum tubal ligation is to be performed before the patient is discharged from the hospital, do not attempt the procedure at a time when it might compromise other aspects of patient care on the labor and delivery unit.‡
  
  
  
  

‡The American College of Obstetricians and Gynecologists (ACOG) has indicated that postpartum tubal ligation "should be considered an urgent surgical procedure given the consequences of a missed procedure and the limited time frame in which it may be performed." ACOG Committee Opinion No. 530: Access to postpartum sterilization. Obstet Gynecol 2012; 120:212–5.

Management of Obstetric and Anesthetic Emergencies

Resources for Management of Hemorrhagic Emergencies

• Institutions providing obstetric care should have resources available to manage hemorrhagic emergencies.


• In an emergency, type-specific or O-negative blood is acceptable.


• In cases of intractable hemorrhage, when banked blood is not available or the patient refuses banked blood, consider intraoperative cell salvage if available.

Equipment for Management of Airway Emergencies

• Labor and delivery units should have personnel and equipment readily available to manage airway emergencies consistent with the NGC summary of the ASA guideline Practice guidelines for management of the difficult airway, to include a pulse oximeter and carbon dioxide detector.
  
  
  
  • Basic airway management equipment should be immediately available during the provision of neuraxial analgesia.
  
  
  • Portable equipment for difficult airway management should be readily available in the operative area of labor and delivery units.
  
  
  • A preformulated strategy for intubation of the difficult airway should be in place.
  
  
  • When tracheal intubation has failed, consider ventilation with mask and cricoid pressure or with a supraglottic airway device (e.g., laryngeal mask airway, intubating laryngeal mask airway, and laryngeal tube) for maintaining an airway and ventilating the lungs.
  
  
  • If it is not possible to ventilate or awaken the patient, a surgical airway should be performed.
  
  
  
  

Cardiopulmonary Resuscitation

• Basic and advanced life-support equipment should be immediately available in the operative area of labor and delivery units.


• If cardiac arrest occurs, initiate standard resuscitative measures.
  
  
  
  • Uterine displacement (usually left displacement) should be maintained.
  
  
  • If maternal circulation is not restored within 4 min, cesarean delivery should be performed by the obstetrics team.
  
  
  
  

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