Maternity Part 2
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Maternity Part 2
BC CRNA Advanced principles Maternity Part2
Alans second lecture 3/24/14
What are the three stages of labor?
: Latent Phase (less than 4cm dilation of cervix) and Active Phase (greater than 4cm dilation of the cervix)
: Complete dilation until delivery (involves descent of the fetus through the pelvis and out the vaginal canal)
: delivery of the placenta
During the first stage of labor, where is the pain coming from?
Visceral pain from uterine contractions and resulting cervical dilation and effacement (shortening and thinning of the cervix) innervate the spinal cord at
During the second and third stage of labor, where is the pain coming from?
caused by the descent of the the fetus and ultimately the placenta through the stretching pelvis and peritoneal structures also innervate the spinal cord at the
S2-S4 nerve roots
Name the non-pharmacologic analgesia for labor
TENS Unit (Transcutaneous Electrical Nerve Stimulation)
How much morphine would you give IV for analgesia for labor?
2-4mg Q3-4 hours --EARLY in labor, don't want baby coming out under the influence :)
How much Dilaudid would you give for analgesia for labor?
1-2mg IV/IM Q1-2hrs
How much Demerol would you give for analgesia for labor?
Q2-3hrs with MAX DOSE of 100mg
How much Fentanyl (IV) would you give for analgesia for labor?
25-50mcg IV Q30-60min
Nubain and Stadol aren't seen as much but what is the dosing for analgesia for labor?
Nubain 10mg IV Q3-6hr
Stadol 1-2mg IV Q3-4hr
How much Ketamine would you give for analgesia for labor?
Ketamine 10-15mg IV (Max dose of 1mg/kg)
Why are opioids typically used early in labor (at least 4 hours prior to delivery)?
Nearly all opioids analgesics readily corss the placenta and can affect the fetus (respiratory depression/acidosis and sedation)
Ketamine may be avoided because of the unpleasant psychedelic and hallucinogenic effects. When is it helpful???
Used as a rescue for a patchy block
The most common and manageable side effect of Labor epidurals is hypotension secondary to sympathetic blockade and resulting vasodilatioin. How do we treat this?
Increased IV fluids
Titrate to effect
Placement of an epidural should only take place where (....in the hospital)
Only attempt in a location where complete anesthesia equipment and resuscitative drugs are available
What are the ABSOLUTE contraindications to epidurals
Skin infection at injection site
Raised intracranial pressure
What are the relative contraindications to epidurals?
Pre-existing neurological disorders (MS)
Fixed Cardiac Output states (AS, CHB, MS, hypertrophic obstructive cardiomyopathy)
Anatomical abnormalities of the vertebral column
Patients with a history of previous back surgery
After performing a physical assessment and obtaining consent, what should we administer prior to placement?
Nonparticulant anatacid prophylaxis (30cc Bicitra) and 500-1000ml of LR fluid bolus
What is the typical depth from skin to the lumbar epidural space
How far into epidural space do you thread the catheter?
Does a negative aspiration negate a potential intrathecal/intravascular placement of your epidural catheter?
No! It could still be misplaced!
What is the test dose for epidural catheter placement?
Lidocaine 1.5% and Epi 1:200,000 (3cc) so 45mg of Lidocaine and 27mcg Epinephrine
If you gave the test dose and the epidural was intrathecally placed, how could you tell?
Lidocaine would give a fast onset of T8-T10 spinal block
If you gave the test dose and the epidural was intravascularly placed, how could you tell?
Epidural would give you an increase in HR and BP (unless the parturient is betablocked)
After you've successfully placed your epidural catheter and given you test dose, what do you give for a bolus?
5cc of 0.25% Bupivacaine and 100mcg of Fentanyl
Begin frequent monitoring of BP for signs of hypotension
What is a typical concentration and rate for an epidural for labor?
0.1% Bupivacaine and Fentanyl 2-5mcg/ml at 6-10ml/hr
Continue monitoring the patient for 15-20min then Q2-3hrs for adequate analgesia & proper motor function & signs of hypotension
How can you treat inadequate analgesia as labor progresses (after you've placed the epidural but before the patient is pushing)?
Additional boluses of 0.25% Bupivacaine 5-10ml
How can you treat inadequate analgesia as labor progresses (epidural is in and the patient is about to start pushing)?
50-100mcg of Fentanyl to avoid bolusing local anesthetics and taking away some motor function
When removing the epidural (after checking with surgeon that there is no uterine atony or bleeding), what should you check to ensure the catheter is intact??
Check and document the black tip of the epidural catheter is intact
What happens if you have an intrathecal catheter instead of an epidural catheter?
give 1/10th the mg volume dose!
Clearly label as INTRATHECAL
Communicate with everyone that is intrathecal
For spinal analgesia for labor, a combination of preservative free opioids is used, why?
Morphine 0.15-0.25mg (slow onset of 30-60min but lasting duration of 4-6hrs)
Fentanyl 12.5-25mcg (fast onset of 1-3 min but only lasts 1-2hrs)
Maternal hypotension is rarely seen when giving spinal analgesia (opioid only), why might you see some mild decreases in BP?
as a resullt of decreased circulating endogenous catecholamines (pain relief)
what is a common side effect of intrathecal narcotics?
What change in fetal heart rate might you see after a spinal analgesia for labor?
Drop in fetal HR (early decelerations) as the fetus rapidly descends through the pelvis and is now relaxed
(Apgars remain high despite the changes in fetal HR)
What helps REDUCE (but not eliminate) the risk of Post Dural Puncture Headaches?
Use of a small guage, pencil point spinal needle (Pencan 25G or Whitacre 25G)
Why are spinal catheters not used?
continuous spinal catheters were associated with cauda equina syndrome
What is cauda equina syndrome?
characterized by varying degrees of persistent saddle anesthesia, sphincter dysfunction resulting in bowel or urinary problems, & rarely paraplegia
How do the baroreceptors influence fetal HR?
influence the fetal HR through the vagus nerve in response to change in fetal BP
Almost any stressful situation in the fetus evokes the baroreceptor reflex which elicits peripheral vasoconstriction and HTN with resultant bradycardia (just like phenylephrine does)
What do the chemoreceptors do?
Chemoreceptors located in the aortic and carotid bodies respond to hypoxia, excess CO2, and acidosis producing tachycardia and HTN
What is the normal fetal HR?
Why do we like variability in the fetal HR?
Baseline variability reflects a healthy nervous system (the baroreceptors and chemoreceptors are responding to the changes and stress of labor appropriately)
Fetal prematurity decreases variability in the HR, so there is little rate fluctuation before how many weeks???
When should fetal HR variability be normal (at how many weeks)?
After 32 weeks
Sustained decreased baseline variability is a potential sign of what?
fetal asphyxia and thus is a nonreassuring FHR
What are fetal HR accelerations?
15 or more beat/min increase lasting for more than 15sec
Are accelerations normal?
Yes they are considered reassuring
Reflect normal oxygenation and are related to fetal activity in response to uterine pressure
Is absence of accelerations normal?
No! Absence of accelerations is nonreassuring
What are early decelerations?
10-40 beats/min decrease should be simultaneous to contractions and are the result of the vagal reflex to head compression
Are early decelerations good or bad?
Good, they are reassuring
What are late decelerations?
onset is 10-30sec after start of contraction & end 10-30sec after contraction ends
What are late decelerations a sign of?
Fetal myocardial ischemia
Are late decelerations life threatening to the fetus?
YES! All late decels are considered potentially threatening to the fetus!
Late decels w/a decrease in variability are nonreassuring
What are variable decelerations?
variable in depth, shape and duration
Acute fall in FHR w/a rapid down slope and a variable recovery phase
Vary in duration, intensity and timing & may bear no constant relationship to uterine contractions
What are variable decels a sign of?
Head or umbilical cord compression
Occur frequently in patients who have experienced premature rupture of membranes and decreased amniotic fluid volume
What is the MOST COMMON fetal heart rate pattern during labor?
Variable decelerations are the most commonly encountered patterns during labor
Variable decelerations are caused by compression of the umbilical cord, which occludes the vein and artery which results in what?
Initially occludes the vein causing acceleration and indicates a healthy response
Occlusion of the artery, results in the sharp down slope
Recovery phase is d/t relief of the compression and the sharp return to baseline, which may be followed by another healthy brief acceleration
Variable decelerations may be classified according to their depth and duration, describe mild, moderate, and severe
: 80bpm lasting less than 30sec
: 70-80bpm and lasts 30-60sec
: below 70bpm and lasts more than 60sec
Variable decelerations are generally associated with a favorable outcome. However, what can persistent deceleration pattern mean?
If it's not corrected, may lead to acidosis and fetal distress, therefore it is non reassuring
Non-reassuring variable decelerations are associated with the loss of beat to beat variability correlate substantially w/fetal acidosis and therefore represent a threat to the fetus
What are the reassuring patterns of fetal heart rate?
Mild variable decelerations (less than 30sec and rapid return to baseline)
Early decelerations (concurrent "mirror image" decrease w/contraction)
Accelerations without other changes
What are the nonreassuring patterns of fetal heart rate?
Decrease in baseline variability
Progressive tachycardia (>160)
Decrease in baseline FHR
Intermittent late decelerations w/good variability
What are the ominous patterns of FHR?
Persistent late dcelerations; esp.w/decreased variability
Variable decelerations w/loss of variability, tachycardia, or late return to baseline
Absence of variability
Severe bradycardia (60-80bpm)
What sensory level do we need for a C sec?
At T4 sensory level, what kinds of HD changes will we see?
High sympathetic blockade and profound vasodilation and potential bradycardia
(Cardiac accelerator originates from 1st-5th thoracic spinal nerves)
What kind of fluid bolus would we give prior to the initiation of the block for a Csec?
1000-1500ml of LR
We get BP Q1min after imitation of the block for Csec, how do we treat hypotension?
Ephedrine 5-10mg or Phenylephrine 40-80mcg
What might you warn the patient about prior to placing a block for Csec (think respiratory)
Quiet respirations causing the patient to feel that she can not breath adequately
What do you do if you're patient states they can't breathe after blocking for a Csec?
Assess for tingling or weak ability to grasp the hands as this implies a low cervical blockade (C5,6,7) and the potential for an increasingly high spinal/epidural
Ability to lift the head implies that the muscles of accessory breathing are intact
When in doubt, get them off to sleep (RSI) and establish GETA
With ROUTINE SCHEDULED Csec what block is preferred?
Spinal because it is faster placement and consistent dense sensory and motor blockade
What is the typical spinal dose for a Csec?
Hyperbaric Bupivacaine 0.75% (7.5mg/ml) is 10.5-15mg
Some people add Fentanyl 12.5mcg or Morphine 0.15mg
A true Crash emergent Csec is happening, when do you induce GETA?
After confirmation of surgical team readiness because incision happens right after you secure the airway
How do you dose a patient who has an epidural in place and needs a Csec?
a labor epidural can be dosed in 5ml increments w/15-20ml of either Chloroprocaine 3% or an alkalinized 2% PF Lidocaine (1ml of NaBicarb 8.4%/10ml of Lido)
Why don't we add epi to our epidural dosing for C sec?
because it will slow the onset of the block!
What happens if the labor epidural catheter migrates intrathecal or intravascular and results in a high spinal or toxic blood level?
Tx w/RSI GETA
How do we treat a patchy or inadequate sensory level labor epidural?
IV Ketamine 10-25mg or 30-50% of N2O
Surgeon may also infiltrate w/Lidocaine
If all else fails=RSI GETA
How long should ELECTIVE Csec fast?
at least 6hrs prior to any anesthetic
Increased risk of aspiration and greater incidence of difficult airway in the parturient, how can we make the situation optimal?
Nonparticulant antacid (30ml Bicitra)
Consider use of Heine flex-tip MAC blade w/short handle to avoid the breasts
Downsize cuff ETT (5.5-6)w/stylet
Ramp patient to facilitate optimum extension of head and thus better view during intubation
After induction and ETT placement, how do we provide GETA?
Maintenance of anesthetic w/potent inhalation agent on 100% oxygen (1.5MAC for 1st min then 2/3 to 1/2 MAC+N2O50-70%)
Are the use of short term low concentration inhaled agents associated w/decreased uterine activity, increased uterine bleeding, or neonatal depression?
What might we give after the delivery of the fetus and placenta?
Antibiotics (now given pre-incision)
Oxytocin 20U/L PSR
Methergine 0.2mg IM or Hemabate 0.25mg IM PSR for uterine atony
How do we assess neonatal respirations and HR?
Respirations assessed by ascultation at a rate of 30-60/min
HR assessed by palpation at the base of the cord @ 120-160bpm
What is a normal APGAR? Moderate impairment? Needs resuscitation?
Moderate impairment 4-6
Needs Resuscitation 0-3
Resuscitation is needed in ___ of births
About ___% of parturients will require non-ob surgery during their pregnancy
What are the common non-ob types of surgery the parturient might have?
cerclage (reinforcement of cervix)
various laparoscopic procedures (gall bladder)
How long should elective surgeries be postponed after delivery?
What teratogens that we should avoid giving the parturient getting non-ob surgery?
Benzodiazepines (cleft palate)
N2O (decrease uterine blood flow)
Ketamine (controversial, may have oxytocic effects on the uterus)
**Esp in 1st trimester
During non-ob surgery on the parturient, how can we maintain placental perfusion?
avoid maternal hypotension, hypovolemia, anemia, hypo/hypercarbia, acidosis, exogenous/endogenous catecholamines
*ABOVE ALL MAINTAIN MATERNAL OXYGENATION*
During non-ob surgery for the parturient, we should assess and intervene at first signs of perterm labor, how?
tocolytics (Ritodine and Terbutaline)
When should we do FHR monitoring?
Pre and post-op after 10-16 weeks gestation
When must we do RSI for GETA in the parturient?
after 10 weeks
When should we maintain uterine dipslacement during non-ob surgery in the parturient?
In supine position after 24 weeks gestation
what is placenta
vents or blocks fetal delivery involves the placenta blocking some or all the cervical
What does placenta previa typically presents w/ what?
painless vaginal bleeding, in fact all parturients w/vaginal bleeding are assumed to have previa until proven otherwise
Active bleeding or an unstable patient/fetus require immediate C/S (plan for a large volume loss case!)
what is placenta accreta, placenta increta, and placental percreta?
: adheres to uterine surface
: invades the uterine muscle
: completely invades uterine muscle and surrounding tissue)
what is Abruptio Placentae?
invovles the premature separation of the life-giving placenta from the uterine wall
PAINFUL vaginal bleeding
What are the risk factors for Abruptio Placentae?
HTN, trauma, short umbi cord, multiparity, prolonged rupture of membranes, cocaine, and ETOH abuse
Can we do regional for a Abruptio Placentae?
Depends, choice based on degree of fetal health/distress, maternal HD stability, and potential coagulopathy
SEVERE abruptio requires Emergency RSI GETA C/S and aggressive volume management
How does uterine rupture typically present?
loss of uterine tone, bleeding, and fetal distress
Sudden painful event will often overtake the analgesics of a labor epidural
: hysterectomy w/aggressive volume management
What is the most common cause of post-partum hemorrhage?
: tocolytic agents, multiple gestation, retained placenta (usually partial) lacerations, and uterine inversion
When is REGIONAL anesthesia contraindicated?????
PATIENTS W/HYPOVOLEMIA (bolded on his notes!)
What three medications may be used to treat post-partum hemorrhage?
What is oxytocin?
The uterine myometrium contains receptors specific to oxytocin
Oxytocin sitmulates the contraction of uterine smooth muscle and thus impedes uterine blood flow
The # of receptors (therefore response) gradually increases throughout pregnancy and peaks at term
Does oxytocin effect maternal BP?
What is the usual concentration of oxytocin?
What is the dose of Methergine?
What is Methergine?
Semi-synthetic ergot alkaloid
Uterine and smooth muscle constrictor
Will methergine increase maternal BP?
What is the does of Hemabate?
What is Hemabate?
Form of prostaglandin
Uterine and smooth muscle constrictor
Does Hemabate effect maternal BP?
can mildly increase BP
What are the causes of umbilical cord prolapse?
premature and artificial rupture of membranes (most common)
Low birth weight
excessive cord length
What is the treatment for umbilical cord prolapse?
immediate Csec (RSI GETA) combined w/manually pushing the cord and possible presenting fetal appendage back up into the pelvis
Parturient may be placed in knee chest position or steep Tburg to help w/fetal perfusion
What is dystocia or ineffective labor caused by?
inadequate uterine contractions
abnormal fetal presentation
What is a prolonged latent phase defined as?
>14hrs in multip
Cervix remains dilated to 4cm or less but completely effaced
during the active phase of labor the cervix should dilate "some" at least every __hrs
What is the treatment of choice to help increase the frequency and strength of contractions?
What is the most common abnormal fetal presentation?
Why might we place an epidural prior to external cephalic version (for breech presentation)?
1) it can be uncomfortable for the mom
2) can result in placental abruption/fetal distress which could require immediate Csec (why we wait until 36 weeks to do it)
What is the mortality rate for amniotic fluid embolism?
80% and a 50% death rate within the 1st hour of occurance
What does amniotic fluid contain that causes an embolism to be so dangerous?
desquamated fetal tissue, prostaglandins, meconium, leukotrines all f which cause severe maternal anaphylactic reaction
What are the s/s of amniotic fluid embolism?
Sudden respiratory distress (tachypnea, cyanosis)
CV collapse and bleeding
Even if stabilized, DIC usually progresses after
What is the treatment of an amniotic fluid embolism?
Stabilization and supportive care
What is the risk of uterine rupture with VBAC?
What should we do 0-24hrs following dural puncture for a PDPH?
encourage fluid intake to increase CSF production
Is an epidural patch typically performed within the first 24 hrs after a dural puncture?
What is the treatment for a PDPH 24-48hrs following dural puncture?
continue conservative management if it doesn't interfere w/daily activities
if that doesn't work then an epidural blood patch is the gold standard
What is the objective of an epidural blood patch (how does it help PDPH)?
Creates a blood clot over the hole in the dura, CSF leak can be slowed or halted entirely
Possible the EBP works by increasing the pressure in the spinal cord
How much blood do we need for an epidural blood patch?
15-20ml of autologous blood
How effective is the epidural blood patch?
What are the complications of an epidural blood patch?
temporary cranial nerve palsies