Analgesia in Labor Lecture Powerpoint Flashcards
Pain of uterine contraction
Conducted thru small sensory nerve fibers of the paracervical and inferior hypogastric plexuses to join the sympathetic nerve chain at L2 L3, pain of uterine contractions often referred to the area over the upper sacrum and the lower lumbar spine (diffuse and not well localized), as fetus descends thru pelvic floor pain becomes predominantly somatic and is better localized, high progesterone levels reduce anesthetic requirements by activating endorphins which increases threshold to pain, but augmentation with oxytocin increases strength of contraction and pain
Parenteral or systemic opioids
Play a role in labor pain relief, inexpensive and require no specialized expertise other than IV access, however often have little effect on maternal pain scores and provide unreliable analgesia and commonly have ADR’s
2 commonly used systemic opioids for labor
- fentanyl
- morphine
Opioid agents impact on fetus
- Reduce fetal heart rate
- neonatal respiratory suppression
- freely crosses placenta
- drug elimination takes longer than in adults
Nonopioid with similar effect to morphine in pain control in labor
IV tylenol
Local infiltration agent for pain relief during labor
1% lidocaine
Excess lidocaine ADR’s (8)
- relaxed feeling
- drowsiness
- lightheaded
- tinnitus
- metalic taste
- cardiac arrhythmia
- arrest
- slurred speech
Pudendal block
Provides analgesia of the vaginal introitus and perineum by bilateral injections of 1% lidocaine 5-10mL for pain relief of the 2nd stage of labor, relatively small systemic absorption therefore little opportunity to affect fetus
Paracervical block
Rarely used for labor pain relief as associated with fetal acidosis and bradycardia, good for excellent pain relief in the first stage of labor, very effective and fast
Regional (neuraxial) analgesia and anesthesia
-Includes epidural and spinal techniques, require administration by qualified healthcare provider, suitable for labor analgesia and operative analgesia, provides pain relief during labor with minimal maternal and neonatal adverse effects, >60% of US women use
Lumbar epidural analgesia
Injection in the potential space between the bone and the dura mater
Epidural advantages (3)
- patient remains awake and cooperative
- incidence of complication is very low
- can be used for analgesia or anesthesia for vaginal or c section delivery
Epidural disadvantages (6)
- possibility of poor perineal analgesia
- presence of hotspots where analgesia is insufficient
- delayed onset of action up to 10 min
- technical difficulty
- accidental dural puncture
- hypotension
Spinal block
Not often used lidocaine or tetracaine not used until all criteria for forceps delivery are met, , excellent anesthetic for C section
Intrathecal narcotic only injection
-used during first stage of labor, no local anesthetic and therefore no paralysis, allowing for ambulation, causes “itching”, 2 hours excellent analgesia, uses fentanyl and morphine
Post spinal headache
Postural headache in 1% of parturients developed after spinal, caused by CSF leaking from puncture site and incidence is reduced with use of noncutting needles in administration of spinal, duration 5-12 days and blood patch can treat in severe cases (draw blood and inject it to clot the CSF leak really fixing headache quick)
General anesthesia for labor
Uncommon method for vaginal or cesarean delivery usually limited to emergency deliveries or when epidural is contraindicated or has already failed, problems is that labor begins without warning so can’t do if on a full stomach (causes aspiration)
General anesthesia and airway management
More challenging in pregnancy, awake intubation with videolaryngoscopy is alternative option
Anethesia risk factors for complication (8)
- marked obesity
- severe edema or anatomical anomalies of face and neck
- small mandible
- short stature, arthritis of neck
- large thyroid
- asthma, copd, cardiac disease
- severe pre/eclampsia
- previous history of anesthetic complications
Anesthesia related death causes (5)
- aspiration
- intubation problems
- inadequate ventilation
- respiratory failure
- cardiac arrest
Anesthestics complications (4)
- all cross placenta
- risk of aspiration of gastric contents
- fasting not always possible
- failed intubation uncommon but serious when occurs
General anesthetic agents (3)
- gaseous nitrous oxide
- inhaled isoflurane and halothane
- IV thiopental or propofol
Epidural does NOT increase ____ rate
C section
Spinal or general anesthesia is appropriate for emergency c section when there is no…
…epidural
Relative contraindication to neuraxial (epidural or spinal)
Thrombocytopenia (safe generally at >80,000)
In absence of contraindication, maternal request is sufficient medical indication for pain relief in…
…labor
Neuraxial (epidural or spinal) procedures must be withheld for 10-12 hours of the last dose of…
…LMW heparin