Complications and Side Effects of Obstetric Neuraxial Anesthesia and Analgesia

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Complications and Side Effects of Obstetric
Neuraxial Anesthesia and Analgesia

• Dmitry Portnoy, MD
• Anesthesiology Department

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Multiple Classifications

• Life-threatening and non-life-threatening
• Common and unusual
• Short term and long term
• Primary system affected (e.g., neuro,
  respiratory, CV etc.)
• Maternal and fetal
• By the agent used
• By timing
• Procedural/Preoperative/Pre- labor analgesia
• Intraoperative/Intrapartum/Immediate
• Postoperative/Postpartum/Delayed

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Procedural/Preoperative/Pre-analgesia

• Inability to reach subarahcnoid space (anatomy,
  position)
• CSF present, but no block (technical, drug, LA
  resistance)
• Inability to locate epidural space
• Inability to thread the catheter
• Intravascular insertion of the catheter
• Unintended dural puncture
• Needle/ catheter damage foreign body formation

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Intraoperative/Intrapartum/Immediate

• Cardio-vascular complications
• Hypotension
• Cardiac arrhythmias
• Cardiac arrest
• Respiratory problems
• Perceived
• Secondary motor blockade
• Unexpectedly high block
• High block
• Total spinal block

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Intraoperative/Intrapartum/Immediate

• Impaired thermoregulation
• Shivering
• Maternal hyperthermia
• Local anesthetic toxicity
• Intravascular injection
• Secondary to large volume
• Nausea and vomiting
• Pruritus
• Anxiety, panic attack

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Postoperative/Postpartum/Delayed

• PPDH
• Urinary retention
• Neurological complications
• Infectious complications
• Back pain
• Unusual (zebra) complications
• Horners syndrome
• Hearing loss
• Swallowing difficulties

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Neurological complications

• Direct injury vs indirect injury
• Transient vs permanent injury
• Cauda equina syndrome
• Transient neurological symptoms
• Epidural abscess
• Epidural hematoma

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Back Pain

• Up to 40 postpartum regardless of
  spinal/epidural
• Localized self-limited back pain is common after
  LEA
• Factors contributing to longer duration
• Use of a large needle
• Multiple attempts
• Traumatic manipulations
• Periosteal trauma
• Supraspinous and muscular hematomas
• Prolong assumption of unusual position
• Sacroiliac strain before resolution of anesthesia

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Maternal Complications and Side effects Related
to Neuraxial Opioids

• Classic side effects
• Respiratory depression
• Urinary retention
• Pruritus
• Nausea and vomiting

• Rare side effects
• Mental status changes
• Hyperalgesia
• Herpes simplex labialis
• Ocular dysfunction
• GI dysfunction
• Thermoregulation dysfunction
• Cardiac dysrhythmia
• Neurotoxicity

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Maternal Complications and Side
EffectsRespiratory Depression

• Early respiratory depression
• Lipophilic epidural drugs
• Develops within 2 hours
• Likely results from systemic absorption
• Rostral spread of lipophilic agents also possible
• Delayed respiratory depression morphine
• Occurs 6-12 hr, up to 24 hr following
  administration
• Results from cephalad migration to ventral
  medulla
• Continues infusion of lipophilic drugs may also
  be implicated

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Maternal Complications and Side
EffectsRespiratory Depression

• Factors increasing risk of respiratory depression
• High and repeated doses of opioids
• Sedatives, co-existing disease
• Lack of opioid tolerance
• Patient position, increased abdominal and
  intrathoracic pressure
• Monitoring and management
• Frequent assessment of somnolence and respiratory
  rate
• Availability of naloxone at the bedside
• Standing order and protocol for treatment of
  respiratory depression
• Availability of a physician who can direct
  resuscitation

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Maternal Complications and Side EffectsPruritus

• Occurrence - very common, but severe only in 1
• May be caused by all opioids and dose unrelated
• Pathogenesis centrally mediated, due to
  cephalad spread
• Histamine release is probably not involved
• Concept of an itch center in lower medulla
• Altered CNS perception of pain
• Treatment and prophylaxis
• Diphenhydramine 25mg (most likely secondary to
  sedation)
• Nalbuphine 5mg, Naloxone 20 40 mcg, naltrexone
  25mg PO
• Propofol 10 mg (mechanism unknown)
• Limiting cephalad spread - use of hyperbaric
  spinal solution

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Maternal Complications and Side Effects

• Nausea and vomiting
• Difficult to determine opioid mediated incidence
  during labor
• Probably due to rostral migration to
  chemoreceptor trigger zone
• More with morphine, dose nondependent
• Urinary retention
• Higher incidence with spinal morphine, not
  related to the dose
• Inhibition of sacral parasympathetic system
  outflow
• Detrussor muscle relaxation results in increased
  bladder capacity
• Treatment catheterization, opioid antagonists

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Maternal Complications and Side Effects

• Mental status changes, CNS excitation
• Sedation cephalad spread, dose related
• Excitation non-opioid receptors interaction
  (basal ganglia)
• Herpes simplex labialis virus (HSV-1)
  reactivation
• Trigeminal ganglion trigger (cephalad migration)
• Skin trigger mechanism secondary to pruritus and
  scratching
• Gastrointestinal dysfunction
• Secondary to spinal opioid receptors interaction
• Delay gastric empting, prolong intestinal transit
  time, dysphagia

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Maternal Complications and Side Effects

• Neurotoxicity
• Not all opioid agents tested for direct effect on
  neural tissue
• Intrathecal butorphanol may cause neural tissue
  damage
• Hypotension
• BP falls by 20 in 14 50 parturients
  following spinal opioid
• Unlikely secondary to direct sympathectomy effect
• Abrupt relief of pain, decrease the level of
  adrenaline
• Opioidergic BP control system?
• Require the same BP monitoring as a routine
  epidural analgesia

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Labor Progress and Neonatal Morbidity

• Effect of neuraxial analgesia on labor
• Cause-and-effect relationship is unclear
• One study showed prolongation of labor
• Some studies indicated increase in instrumental
  deliveries
• No difference in neonatal outcome
• Fetal effects
• Remote possibility of respiratory depression or
  FHR changes
• Mostly mediated by systemic absorption
• Small doses of neuraxial opioids appeared to be
  safe
• Epidural opioids tend to accumulate with time
• Possibility of fetal bradycardia with IT
  sufentanil