OB caring for pt w labor epidural Flashcards
An epidural is important for blunting the HD effects from contractions in what sub populations?
mitral stenosis, spinal cord injury, intracranial neuro vascular lesions, preeclampsia
Absolute contraindications for laboring epidural?
refusal, uncooperative, increased ICP, infection at site of needle placement, frank coagulopathy, severe hypovolemia, anticoag therapy, decreased FHR variability or late decels, known allergy to med given
Relative contraindications to laboring epidural?
systemic maternal infection, preexisting neuro deficiency, mild or isolated coagulation abnormalities, relative hypovolemia, poor staffing
Moving towards the spinal cord from the epidural space, what are the 4 membranes that cover the spinal cord going from outermost to innermost?
dura, arachnoid, subarachnoid, pia mater
This is the outermost layer covering the nerve roots
dura mater
This layer is thin, spider like and forms the middle layer
arachnoid mater
This layer beneath the arachnoid matter and filled w CSF?
subarachnoid mater
This is the innermost layer and adheres tightly to the spinal cord and brain
pia mater
When opioids and LA are used for epidurals, they collect in?
the fat
Epidural space contains?
fat, epidural veins, lymphatics, segmental arteries, nerve roots
Medications used in epidurals act on receptors in the?
dorsal horn by diffusing across meninges and CSF
C6 dermatome?
thumb
C8 dermatome?
ring/little finger
T 4 dermatome?
nipple line
T6 dermatome?
xiphoid line
T 10 dermatome?
umbilicus
S2, S3, S4 dermatome?
perineal
Poss situations causing inadequate pain coverage w epidural placement?
BMI >30, short or tall, previous spinal surgeries, variety of musckuloskeletal disorders, hx of previous epidural, radicular pain during placement, posterior presentation of the fetus, labor >6 hours
some troubleshooting suggestions for unsatisfactory labor epidural?
manipulate epidural catheter, add more LA, reposition, replace epidural, single shot spinal, continuous spinal, combined spinal epidural, place additional epidural, IV meds
Some causes of an adequate level but insufficient density of block?
not enough time, loss of LA (volume), inadequate % of LA, pt overexpectations
Some causes of satisfactory density but inadequate segmental level?
small vol of LA, insufficient time, loss of LA, anatomical features such as previous surgery, allow more time, additional epidural
Causes of not working epidural that had been working?
migration in to subarachnoid space (total spinal), intravascular, laterally (unilat block), completely out, labor progression, dysfunctional labor, pt perception changed
If pt has a lateral/one side block, what is something you can try?
have patient lie painful side down and bolus while lying
What can you do to troubleshoot an epidural that was working and is currently not?
catheter exam, redose, give more volume, add opioids, % LA, replace
Epidurals are typically placed at what level?
L3-4, L4-5
T10-L1 innervates what organs?
uterus, cervix, upper portion of vag
S2-S4 innervates what part of body?
perineum
First stage labor pain is visceral or somatic?
visceral
Second stage labor pain is visceral or somatic?
somatic
Epidural infusions tend to go up or downward more readily?
upward
Why are the nerve fibers for the 2nd stage of labor harder to reach?
further from tip of epidural catheter, larger in diameter, thicker dura
A pt w this has increased epidural failure?
chronic back pain
Pt’s w unilateral sciatica of the affected nerve become blocked how much later than nerves on the contralateral side?
10-70 min later
ASA rec on antiplt drugs?
should be stopped before epidural and measure INR/PTT
ASA rec on plavix?
does not increase the risk of spinal hematoma
ASA rec on fibrinolytic or thrombolytic drugs?
extreme caution should be used when placing epidural or spinal in these pts
ASA: SQ hep?
not contraindicated. give SQ hour after epidural or spinal placement, remove catheter one hour before SQ hep given or 2-4 hours the last dose
ASA on LMWH?
places pt at increased risk of spinal hematoma. in extreme cases when must have spinal/epidural spinal must be dosed 10-12 hours after last dose of LMWH, remove catheter prior to starting LMWH 10-12 hours after the last dose of LMWH given w subsequent doses given at least 2 hours after catheter removed
What influences and opioids onset and duration of action in epidural?
lipid sol
Lipid sol opioids have a what duration and onset of action?
short duration, fast onset of action (fent, meperedine)
Highly lipid sol drugs have a short mechanism of action in epidural d/t?
rapid vascular absorption and slow rostral diffusion in CSF, elimination occurs at the arachnoid granulations
2 opioids that are hydrophilic?
morphine and hydromorphone
Hydrophilic opioids have what onset of action and duration?
slower onset, longer duration
Do hydrophilic or lipid sol drugs have a greater dermatological spread providing analgesia to larger areas?
lipid sol
Onset and duration of action of fent in epidural?
5 min; 4-6 hours
Onset and duration of action of meperdine in epidural?
5-10 min; 6-8 hours
Onset and duration of action of hydromorphone in epidural?
15-30 min; 6-18 hours
Onset and duration of action of morphine in epidural?
30-60 min; 6-24 hours
Why do you have to be especially careful with hydrophillic opioids in epidural?
cause resp depression soon after admin and delayed like 24 hours after admin
Lipid sol or hydrophillic meds are more likely to spread rostally?
hydrophillic
Should the pt be on po opioids if had them in epidural?
no
Why are pts at greater risk of N/V when received opioid in epidural?
rostral spread of opioid in CSF to chemoreceptor trigger zone in brainstem
It is postulized that itching caused by opioids in epidural is caused by?
alterations in spinal and trigeminal nerve processing. the modulation of nociceptive input is interpreted at a higher level as an itch
What is a treatment for the itch from opioids in epidural?
nubaine: mixed agonist/antagonist that antagonizes the mu opioid kappa receptors which produce analgesia
What will produce a motor block?
increased volume and higher percent of LA in to epidural space
This LA provides the best sensory block w minimal motor block?
ropiv
Ropiv is also commonly used for what 2 reasons?
quick onset w long duration of action
Systemic LA side effects?
lightheadedness, dizzy, metallic taste, ringing in the ears, shivering, muscle twitching, tremors, convulsions, CNS depression and resp arres, hypotension
Pt should be positioned for epidural how?
sitting laterally w knees and back flexed
Fent 2mcg/mL/Ropivacaine 0.2% NaCl 0.9%: min and max continuous dose and appropriate bolus dose?
min: 8mL/hr; max: 14 mL/hr; bolus: 4 mL, max 3 bolus doses in an hour; max 1 hour limit= 26 mL
Can a person eat w epidural?
clear liquid only
What does the baby have to have during epidural placement?
FHT tracing before placement and continuously after placement if poss
Pulse ox should be used when following epidural placement?
continuously during test dose and initial bolus period, record at least q hr after that
BP should be recorded how often after epidural placement? After a bolus, the BP should be obtained how often?
q5 min x 4, q15 min x 2, q 30 min thereafter if stable/ q5 min x 4 after bolus
Once an hour, what should be recorded?
dermatome level, RR, pain score, sedation score
Q4 hours what should be recorded?
total vol of epidural med
