OB Anesthesia

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OB Anesthesia

• Denise Weiss DO
• Anesthesiologist

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Goals of obstetrics

• Healthy mom/baby happy and healthy doctors and
  nurses, family

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OB Anesthesia

• NPO guidelines
• Solid food (fatty foods) 8hrs
• Light meal (toast, crackers, etc) 6 hours
• Clear liquids 2 hours
• Breast milk 4 hours
• On L/D clear liquids ok during labor, (often only
  ice chips allowed)
• Stricter adherence to ice chips if higher risk of
  operative delivery
• Scheduled inductions should be instructed to be
  NPO
• All pregnant pts are considered to have full
  stomachs but the goal is to minimize risk if need
  for intubation occurs

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OB Anesthesia

• Reasons for NPO guidelines
• Higher risk of aspiration in pregnant patients (1
  in 661 vs 1 in 2131 gen pop)
• Increased intragastric pressure due to large
  uterus
• LES is pushed up and to the left (sim to hiatal
  hernia)
• Decreased LES tone secondary to progesterone
• High incidence of GERD
• Gastric pH is more acidic
• Active phase of labor slows gastric emptying

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OB Anesthesia

• Higher risk of difficulty in airway management
• Morbidity/mortality in pregnant pts have been
  attributed often to failed or difficulty managing
  the airway
• Airway is more friable and edematous in pregnant
  pts
• Increased breast size can make laryngoscopy very
  difficult
• Decreased FRC so desaturate quickly

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OB Anesthesia

• pH less than 2.5 and gastric volume greater than
  25ml are identified risk factors for aspiration
• Pregnant pts going to CS either emergently or
  scheduled receive pharmacologic prophylaxis (we
  use reglan and alka selzer gold, bicitra
  increases pH without altering volume)

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OB Anesthesia

• Difficult airway
• Incidence of failed intubation in obstetric pts
  _at_1300
• 12330 in general OR population
• Airway complications are the leading cause of
  anesthesia mortality
• Single largest class of injury related claims
  from the ASA Closed Claims database involves
  respiratory events

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OB Anesthesia

• Basic Needs for the OR
• Monitors
• ECG,NIBP,SPO2, FHR monitor, suction
• Equipment for difficult airway, and emergency
  drugs
• Checked daily

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OB Anesthesia for C-Section

• Spinal
• Epidural
• Combined Spinal/epidural
• General
• Local

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Contraindications for Neuraxial Techniques

• Pt refusal or inability to cooperate
• Increased ICP secondary to mass lesion
• Skin or soft tissue infection at site of needle
  placement
• Coagulopathy
• Uncorrected maternal hypovolemia
• Low platelets (depends)

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Complications with Neuraxial Techniques

• Infection
• Postdural Puncture Headache
• Incomplete or failed block
• Neurologic injury(incidence is 20 in 1.2million
  for subarachnoid blocks, 20 in 450,000 for
  epidurals)
• Meningitis or arachnoiditis
• Spinal hematoma(sharp back and leg pain-numbness
  and motor dysfunction(loss of bowel/bladder fxn)
• Emergent MRI or CT and referral (6-12 hr window
  for decompression)

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Spinal and Epidural Anesthesia
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Combined Spinal/Epidural
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General Anesthesia

• Maternal refusal or inability to cooperate with
  neuraxial tech
• Presence of contraindication to neuraxial tech
• Insufficient time to induce neuraxial tech(cord
  prolapse with persistent bradycardia)
• Failure of neuraxial technique
• Fetal issues (EXIT procedure)

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Local Anesthesia

• Very rarely used
• Dire emergencies when anesthesiologist/CRNA not
  available
• Success dep on avoiding use of retractors, and
  not exteriorizing the uterus.
• After delivery of baby, obtain hemostasis until
  arrival of anesthesia personnel

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Local Anesthesia

• 0.5 lidocaine with epi
• 25g spinal needle to create skin wheal just below
  umbilicus directed toward symphysis pubis. SQ
  injection along this full area.
• Ideally wait 3-4 min to take effect?
• Vertical incision to rectus then local into
  rectus fascia and muscles. Takes 4-5min for
  anesthesia to be complete?

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Local Anesthesia

• Parietal peritoneum infiltration and incision
• Visceral peritoneum infiltration and incision
• Paracervical injection
• Uterine incision and delivery
• Obtain hemostasis
• Await availability of general anesthesia

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Local Anesthesia

• Disadvantages
• Pt discomfort
• Risk for local anesthetic toxicity (may use up to
  100ml of local
• Difficult operating conditions to say the least

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Maximum Local Anesthetic Dosages

• Easy formula for bupivicaine (for 0.25 can give
  1cc/kg, for 0.5 can give 1/2cc per kg.
  Lidocaine 4cc/kg plain, 7cc/kg with epi (for
  obese pts keep in mind max dose)

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PCA Fentanyl

• Great alternative for pts who cannot have an
  epidural
• All opioids cross placenta by diffusion secondary
  to lipid solubility
• All are associated with neonatal depression
• Fentanyl readily crosses placenta but avg
  umbilical to maternal conc ratio is low at 0.31
• Studies show reduced FHR variability but
  difference in APGAR scores, respiratory
  depression and Neurologic and Adaptive Capacity
  scores at 2-4 hrs or 24 hrs compared to infants
  whose mothers did not have fentanyl(Am Journal of
  Obst/Gyn Anesth/Analgesia)

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PCA Fentanyl

• Rapid onset
• High potency
• Short duration
• No active metabolites
• One of most commonly used for PCA

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PCA Fentanyl

• Must have resuscitation equip available
• Pulse oximetry, /- etCO2 monitoring
• One/one nursing
• Education of family members
• Loading dose (50-150mcg
• Bolus 25-50mcg(start at 25, and assess)
• Lockout 10min
• No basal rate

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PCA Fentanyl

• As labor progresses may need to decrease lockout
  time to 5min

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OB in Rural Areas

• Likely will not have immediately available
  anesthesia provider
• OB nurses can assist with management of epidural
  infusions
• ASA has a consultation program that will help
  with setting up the anesthesia service to fit the
  needs of the facility
• Consensus of all involved that OB anesthesia is a
  priority and a worthwhile goal

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OB in Rural Areas

• Anesthesia provider does NOT have to stay in
  house during course of epidural infusion
• ASA recommends it but recognizes difficulty

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Questions???