Complications in OB anesthesia Flashcards
What is the most common cause of postpartum maternal palsy?
cephalopelvic disproportion which results in lumbosacral trunk compression as it crosses pelvic brim by the fetal head.
Epidural hematoma
Rare complication of neuraxial blockade
Usually occur in patients with hemostatic abnormality or coagulopathy.
Can occur with block placement or catheter removal, so insertion and removal should only occur when coagulation function is normal.
How long do you avoid neuraxial block if therapeutic anticoagulated?
24 hours
How long do you avoid neuraxial block if prophylactically anticoagulated?
12 hours
How long after the last dose do you remove the catheter?
12 hours
How long after a block is placed or removed do you can you give hepain?
2-4 h
Other considerations for LMWH and blocks
Avoid concurrent NSAIDs or anticoagulants.
Consider altering LWMH dose or monitoring anti-Xa activity.
Signs and Symptoms of Epidural Hematoma
Bilateral leg weakness
Incontinence
Absent rectal sphincter tone
Back pain
If hematoma suspected pt must get a stat CT or MRI
Surgical decompression must occur w/in 6 hrs for full neurological recovery to occur
Can bottles of 10% iodine become colonized after a single use?
yep
epidural abcess
If an infection is present it takes 4-10 days for sx (usually pain; loss of function) to occur.
Treatment – antibiotics and laminectomy have 6-12 hr window before permanent damage.
Presentation of epidural abscess
Severe back pain
Worse with flexion; sometimes with radiation
Exquisite local tenderness
Fever, malaise, meningitis-like headache with neck stiffness
Laboratory changes
Inc. WBC, inc. ESR, positive blood culture
Progression over hours-days to neuro deficit or osteomyelitis
Epidural space is very resistant to toxicity because:
very vascular
Intact membrane between it and the subarachnoid space
Transient Neurological Symptoms (TNS)
Pain and dysesthesia in buttocks, legs or calves that can follow SAB, resolves w/in 72 hrs
Most commonly caused by lidocaine spinals
Seems more associated w/ lithotomy position, high doses of concentrated lidocaine (~5%).
Where is the conus?
Conus is at T12-L3
Do you do a block on a sleeping patient?
do not do regional blocks on sleeping patients – they can’t tell you if there’s something happening/pain
Lithotomy stirrups- compress the ____ ______ nerve
Lithotomy position- ______ nerve and ______ nerve
Lithotomy stirrups- compress the common peroneal nerve
Lithotomy position- femoral nerve and obturator nerve
Ranges from transient ischemic injury to axonal crush
Recovery 2-6 days if mild; to 2-3 years if severe
Postpartum foot drop happens from compression of what?
Either common peroneal nerve from stirrups or brow compression of lumbosacral trunk
Principal determinants of “spinal headache” are?
size of dural hole and type of needle used.
Throbbing, postural, variable distribution.
Onset is typically 12-48 hr. after dura puncture.
Duration is a few days to weeks.
How much CSF is made per day?
Normal CSF volume is 150cc.
450 cc of CSF is made per day.
Acute loss of as little as 20 cc of CSF will produce headache symptoms, caused by sagging of intracranial contents and stretching of the pain sensitive tissues when the patient assumes an upright posture.
What needle size has the highest risk for PDPH?
16-18 ga epidural – 75-80% chance of PDPH
22 ga Quincke – 30-50% chance of PDPH
25 ga Quincke – 8-10% chance of PDPH
24 ga Sprotte – 3-5% chance of PDPH
25 ga Whitacre – 1-2% chance of PDPH
Are pencil point needles better than cutting needles?
Yes!
Pencil point needles significantly better than cutting tip needles because dura fibers are not cut but just pushed apart
What is the hallmark of PDPH?
The hallmark of a PDPH is continuous head pain when patient sitting or standing that is completely or almost completely relieved by recumbence.
Differential Diagnosis for PDPH
usually photophobia and headache
Most common cause of perioperative headache
Caffeine withdrawal
What can happen if you don’t treat PDPH?
Chronic headache
Permanent impairment
Convulsions d/t cerebral vasospasm
“Coning” and brainstem death
What is definitive therapy for PDPH?
Epidural Blood Patch
Epidural space is identified and 15-20 cc of the patient’s own blood is injected (in strict aseptic manner) into the epidural space. Start slow and stop either when patient says headache is gone or they have a pressure sensation in the ears.
Resolution of the headache is nearly instant and sustained ~ 80% of the time. A repeat increases the success rate to about 90%.
Aspiration of Gastric Contents
Accounts for 1/3 of anesthetic lawsuits in obstetric population
Suspect aspiration with:
Hypoxia
Pulmonary edema
Bronchospasm
Prevention OF ASPIRATION
Cricoid Pressure
Fasting- Elective C/S patients should fast at least 6 hrs. even if regional planned, laboring patients can have limited amounts of clear liquids during labor- At all times the parturient is considered to have a full stomach!
Sodium Citrate works within minutes to raise gastric pH- lasts ~30 min
H2 blockers (famotidine, ranitidine): Take at least 30 min to work
Metoclopramide (Reglan): dopamine antagonist which acts on intestinal tract via release of acetylcholine, this increases gut motility and facilitates gastric emptying, requires 40-60 min.
Management of Aspiration
Intubation and positive pressure ventilation w/ PEEP.
Use only enough O2 to maintain O2 saturation in the 90s (high FiO2 may exacerbate lung injury!!!!!)
Suction as much as possible from airway.
Rigid bronchoscopy only used when large food debris needs to be removed.
Prophylactic antibiotics are controversial, may be detrimental.
Prophylactic steroids have no role.
Lavage is not routinely recommended.
Patients may become hypovolemic through fluid shifts
