Recent Advances in Obstetric Anaesthesia

Slide 1: Neuraxial Techniques Have Replaced General Anesthesia as the Standard of Care

Neuraxial anesthesia (spinal or epidural) should be selected in preference to general anesthesia for most cesarean deliveries. 1

The shift from general to neuraxial techniques has dramatically improved maternal safety and reduced anesthesia-related mortality 2, 3
Spinal anesthesia with pencil-point needles (not cutting-bevel needles) minimizes postdural puncture headache risk 1
For urgent cesarean delivery, an existing epidural catheter can be rapidly dosed as an alternative to initiating spinal or general anesthesia 1
General anesthesia remains appropriate only in specific emergencies: profound fetal bradycardia, ruptured uterus, severe hemorrhage, major placental abruption, umbilical cord prolapse, or preterm footling breech 1

Slide 2: Advanced Airway Management Protocols for Failed Intubation

The Obstetric Anaesthetists' Association and Difficult Airway Society have established comprehensive algorithms for managing difficult and failed tracheal intubation in obstetrics. 1

Pre-Theatre Preparation

Every woman must have documented airway assessment including Mallampati grade, neck movement, mouth opening, thyromental distance, and jaw protrusion 4
Women with predicted significant airway difficulties should be referred antenatally for specific anesthetic and obstetric management planning 1, 4
Standardization of airway equipment within hospitals is highly recommended, with regular checks of airway trolleys 1

Rapid Sequence Induction Optimization

Position patients in 20-30° head-up position to increase functional residual capacity and safe apnea time 1
Have video laryngoscopes, supraglottic airway devices, and front-of-neck access equipment immediately available 4
Before induction, discuss with the obstetric team whether to wake the patient or proceed with surgery if intubation fails 1

Failed Intubation Decision-Making

The decision to wake versus proceed depends on maternal factors (hemodynamic stability, aspiration risk), fetal factors (reversible vs. irreversible causes of distress), and available resources 1
Irreversible causes of fetal distress include major placental abruption, fetal hemorrhage, ruptured uterine scar with placental/fetal extrusion, and umbilical cord prolapse with sustained bradycardia 1
If proceeding with surgery after failed intubation, maintain cricoid pressure until delivery, use controlled ventilation with neuromuscular blockade (monitored with peripheral nerve stimulator), and have the most senior surgeon operate 1

Slide 3: Phenylephrine Over Ephedrine for Hypotension Management

Phenylephrine should be selected over ephedrine for treating hypotension during neuraxial anesthesia in the absence of maternal bradycardia. 1

Phenylephrine improves fetal acid-base status compared to ephedrine in uncomplicated pregnancies 1
IV fluid preloading or coloading may be used to reduce maternal hypotension frequency after spinal anesthesia, but do not delay spinal initiation to administer a fixed fluid volume 1
This represents a significant shift from historical practice that favored ephedrine due to concerns about uteroplacental vasoconstriction 1

Slide 4: Labor Analgesia Advances: Early Neuraxial and Patient-Controlled Techniques

Neuraxial analgesia is the most effective method for labor pain and should be offered early, not withheld based on arbitrary cervical dilation. 5, 6

Early Epidural Placement

Early insertion of epidural catheters should be considered for complicated pregnancies (twin gestation, preeclampsia, anticipated difficult airway, obesity) to reduce the need for emergency general anesthesia 1, 5
Epidural analgesia does not increase the incidence of cesarean delivery 6

Patient-Controlled Epidural Analgesia (PCEA)

PCEA provides effective and flexible labor analgesia with reduced local anesthetic dosages compared to fixed-rate continuous infusion 1
PCEA may be used with or without a background infusion 1
Continuous infusion epidural with dilute local anesthetics plus opioids minimizes motor block while maintaining effective analgesia 5

Combined Spinal-Epidural (CSE) Techniques

CSE provides rapid onset analgesia for labor 1
Use pencil-point spinal needles instead of cutting-bevel needles to minimize postdural puncture headache 1
If labor duration is anticipated to exceed the analgesic effects of spinal drugs, or if operative delivery is reasonably possible, choose a catheter technique over single-injection 1

Slide 5: Remifentanil Patient-Controlled Analgesia as Neuraxial Alternative

Remifentanil PCA is indicated specifically when epidural analgesia is contraindicated, refused, or unavailable—not as an adjunct to neuraxial techniques. 6

Remifentanil has a context-sensitive half-life of <10 minutes with minimal neonatal sedation 6
Mandatory monitoring includes continuous pulse oximetry, capnography, respiratory rate assessment, and non-invasive blood pressure every 5 minutes initially 6
No published guidelines support combining remifentanil infusion with epidural analgesia due to heightened respiratory depression risk 6
When parenteral opioids are administered with neuraxial opioids, increased monitoring intensity and duration are mandated 6

Slide 6: Multimodal Post-Cesarean Pain Management

Baseline analgesia after cesarean delivery should include neuraxial morphine (or hydromorphone) plus scheduled acetaminophen and NSAIDs, with short-course opioids only for breakthrough pain. 5

Neuraxial Opioids

Intrathecal morphine 50-100 μg administered pre-operatively provides superior postoperative analgesia 5
Epidural morphine 2-3 mg can be used if an epidural catheter is already in place 5
Neuraxial opioids are preferable to intermittent parenteral opioid injections for post-cesarean analgesia 1

Non-Opioid Baseline Regimen

Scheduled acetaminophen 975 mg every 8 hours combined with ibuprofen 600 mg every 6 hours 5
Ketorolac 15-30 mg IV/IM every 6 hours (maximum 48 hours) for severe pain 5
Single intraoperative low-dose ketamine (≈10 mg) can enhance opioid analgesia without hallucinations 5

Opioid Prescribing Principles

If opioids are necessary, use the lowest effective dose for the shortest time possible 5
Limit hydrocodone 5 mg to 5-10 tablets total for severe pain after vaginal delivery 5
Morphine is the preferred opioid when strong analgesia is required; only small amounts cross into breast milk 5

Slide 7: Codeine Must Be Avoided Entirely in Obstetrics

Codeine should never be prescribed to pregnant or breastfeeding patients due to unpredictable CYP2D6 metabolism and documented cases of neonatal death. 5

Up to 28% of individuals of Middle Eastern/North African ancestry and 10% of Caucasians are ultra-rapid metabolizers, leading to dangerously high morphine levels in breast milk 5
The CDC, FDA, and European Medicines Agency recommend against codeine use in breastfeeding women 5
Codeine-containing medications carry risk of severe neonatal respiratory depression and death in ultra-rapid metabolizers 5

Slide 8: NSAID Timing: Critical Gestational Age Cutoff

NSAIDs must not be used after 28 weeks gestation due to risk of premature ductus arteriosus closure and oligohydramnios. 5

Ibuprofen is particularly useful for inflammatory pain during the second trimester (weeks 14-28) 5
Postpartum, NSAIDs (ibuprofen, diclofenac, ketorolac) are safe and effective during breastfeeding with only small amounts detected in breast milk 5
Avoid NSAIDs in women with preeclampsia if possible, especially with acute kidney injury 5
Aspirin in analgesic doses should be avoided during pregnancy; low-dose aspirin for antiplatelet action can be used if strongly indicated 5

Slide 9: Acetaminophen Safety Concerns: New Evidence on Neurodevelopmental Risk

Recent evidence links prolonged acetaminophen use (>28 days) or second-trimester exposure with increased risk of ADHD and autism spectrum disorder in offspring. 5

Despite these concerns, acetaminophen remains the first-line medication for pain management during pregnancy due to its favorable safety profile 5
Acetaminophen is considered the safest analgesic for mild to moderate pain in any stage of pregnancy 5
The amount crossing into breast milk is significantly less than pediatric therapeutic doses, making it safe during lactation 5
This new evidence should prompt judicious use: lowest effective dose for shortest duration necessary 5

Slide 10: Aspiration Prophylaxis: Risk-Stratified Approach

Women should be stratified into low- or high-risk categories for requiring general anesthesia, with different oral intake guidelines for each group. 1

Low-Risk Women

Allowed a light diet during labor 1
Gastric clearance in pregnant women not in labor is the same as non-pregnant patients 1

High-Risk Women

Should not eat but may have clear oral fluids, preferably isotonic drinks 1
Oral H2-receptor antagonists every 6 hours during labor 1
If anesthesia is required for delivery, administer IV H2-receptor antagonist if not already given 1
Sodium citrate should be given immediately before induction 1

Postpartum Tubal Ligation

No oral intake of solid foods within 6-8 hours of surgery, depending on fat content 1
Consider aspiration prophylaxis 1

Slide 11: Management of Opioid Use Disorder in Pregnancy

Women receiving methadone or buprenorphine for opioid use disorder must continue their maintenance dose throughout pregnancy, labor, and the postpartum period—abrupt withdrawal is contraindicated. 5

Maintenance Therapy Principles

Never discontinue maintenance opioid therapy during labor or postpartum, as this increases risk of withdrawal and relapse to illicit opioid use 5
Continue the maintenance dose of methadone or buprenorphine throughout pregnancy and delivery 5
Dividing the maintenance dose may improve analgesic coverage due to shorter half-life 5

Labor Analgesia

Early neuraxial analgesia (epidural or spinal) should be offered to laboring patients with opioid use disorder 5
Opioid agonist-antagonists (nalbuphine, butorphanol) must be avoided as they can precipitate acute withdrawal 5

Postpartum Pain Management

Multimodal baseline regimen of scheduled acetaminophen and NSAIDs is recommended 5
If inadequate after 24 hours, patients on buprenorphine may require higher doses of full-agonist opioids (fentanyl, hydromorphone) via patient-controlled analgesia 5
Pain management requires a multidisciplinary approach 5

Slide 12: Maternal Cardiac Arrest Protocol: The 4-Minute Rule

If maternal cardiac arrest occurs, standard resuscitative measures should be initiated immediately, with cesarean delivery performed by 4 minutes if circulation is not restored. 1

Basic and advanced life-support equipment must be immediately available in the operative area of labor and delivery units 1
Uterine displacement (usually left displacement) should be maintained during resuscitation 1
Cesarean delivery within 4 minutes improves both maternal and neonatal outcomes by relieving aortocaval compression and improving venous return 1

Slide 13: Point-of-Care Ultrasound and Viscoelastometry

Point-of-care ultrasound of the lungs and stomach, along with viscoelastometry-based coagulation testing, are revolutionizing perioperative obstetric care. 7

Gastric ultrasound can assess aspiration risk by evaluating gastric volume and content 7
Lung ultrasound can rapidly diagnose pulmonary edema, pneumothorax, or pleural effusion in critically ill parturients 7
Viscoelastometry (thromboelastography/rotational thromboelastometry) provides real-time assessment of coagulation status, guiding transfusion therapy in obstetric hemorrhage 7
These techniques have improved quality of care and perioperative outcomes in parturients with comorbidities 7

Slide 14: Intrauterine Fetal Resuscitation Before Emergency Delivery

Intrauterine fetal resuscitation should be employed as appropriate before emergency operative delivery, with urgency re-evaluated after transfer to the operating theatre. 1

Fetal condition is likely to be maintained during a delay in the majority of cases 1
Potentially reversible causes of fetal distress include uterine hyperstimulation, hypotension after epidural anesthesia/analgesia, and aortocaval compression 1
Significant decline in neonatal pH with increasing bradycardia-delivery interval occurs only with irreversible causes (major placental abruption, fetal hemorrhage, ruptured uterine scar, umbilical cord prolapse with sustained bradycardia) 1
This approach allows time for safer anesthetic technique selection and reduces unnecessary emergency general anesthesia 1

Slide 15: Team-Based Coordinated Care and Safety Systems

The practice of obstetric anesthesia must expand beyond provision of safe analgesia and anesthesia to lead in developing comprehensive safety systems and team-based coordinated care. 8

Multidisciplinary Collaboration

The World Health Organization surgical checklist should be used before each theatre procedure, often modified locally for cesarean section 1
Some units use a specific anesthetic checklist in addition to the surgical checklist 1
Comprehensive multidisciplinary planning involving anesthesiologists and high-risk obstetrical teams is essential to minimize maternal and fetal morbidity and mortality 4

Risk-Based Classification

National obstetric organizations have proposed Levels of Maternal Care to funnel complex obstetric patients toward high-acuity centers where they can receive more effective care 8
This initiative addresses the increasing burden of high-risk parturients who are older with more pre-existing conditions and complex medical histories 8

Communication Protocols

Clear procedures for contacting a second anesthesiologist should be established, with induction delayed if appropriate while awaiting their attendance 1, 4
The anesthesiologist should be informed by the obstetrician about clinical details and current urgency category 1

Slide 16: Maternal Safety Improvements Despite Increasing Complexity

Anesthesia-related adverse events and morbidity are decreasing despite increasing obstetric complexity, reflecting an ongoing focus on safe systems of anesthetic care. 8

Maternal mortality and morbidity in the United States have increased in recent years due to changing demographics of the childbearing population 8
Pregnant women are older with more pre-existing conditions and complex medical histories 8
Cardiovascular and non-cardiovascular medical diseases now account for half of maternal deaths in the United States 8
Despite these challenges, anesthesia-related maternal mortality is extremely rare in the developed world due to changes in training, service, technical advances, and multidisciplinary approach to care 3, 9

Slide 17: Equipment and Facilities Standards

Equipment, facilities, and support personnel available in the labor and delivery operating suite should be comparable to those available in the main operating suite. 1

Resources for treating potential complications (failed intubation, inadequate anesthesia, hypotension, respiratory depression, local anesthetic systemic toxicity, pruritus, vomiting) must be available 1
Appropriate equipment and personnel should be available to care for obstetric patients recovering from major regional or general anesthesia 1
Standardization of airway equipment within the hospital is highly recommended 1, 4

Slide 18: 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. 1

IV or sublingual nitroglycerin can provide successful uterine relaxation and placental removal 1
Before administering neuraxial anesthesia for retained placenta removal, hemodynamic status should be assessed 1
If an epidural catheter is in place and the patient is hemodynamically stable, consider providing epidural anesthesia 1
In cases involving major maternal hemorrhage with hemodynamic instability, general anesthesia with an endotracheal tube may be considered in preference to neuraxial anesthesia 1

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