Complications in OB Anesthesia Flashcards
What is the most common cause of postpartum maternal palsy?
Cephalopelvic disproportion
- Its the results in lumbosacral trunk compression as it crosses pelvic brim by the fetal head
Postpartum maternal palsy was more common in the past. Why?
Long labors and difficult forceps deliveries were more common
New research has shown that cases of postpartum maternal palsy deficits all resolved within ____ hrs
72
Research showed that problems with postpartum maternal palsy were more frequent with _____
patients who had no anesthesia
Also, problems were the same for epidurals and GA
What % of parturients describe backache as a complication?
75%
New onset for 60% of these patients
Backache complications in regards to birthing is thought to be related to what two pregnancy-related changes?
- Lumbar lordosis to counterbalance growing uterus
- Laxity of sacrococcygeal, sacroiliac, pubic joints.
Based on research, What % of patients had backache lasting 6months or more?
What was a unique feature of this group?
What % of patients of who did receive regional anesthesia report backspin lasting 6 months or more? Why so?
- 5%
- These patients delivered w/o regional anesthesia
- 18%
- Soft tissue trauma
What are 3 complications related to neuraxial blocks?
- Nerve injury
- Postdural Puncture Headache (PDPH)
- High or total spinal anesthesia
What are the 5 causes of nerve injury complication for neuraxial blocks?
- Epidural Hematoma
- Epidural Abscess
- Chemical nerve injury
- Needle trauma
- Positioning injury
What is the incidence of a epidural hematoma from neuraxial blockade?
1:250,000 to 1:500,000
Epidural hematoma usually occur in patients with ______ or _______
- Hemostatic abnormality
- Coagulopathy
When do epidural hematomas usually occur?
- Block placement or catheter removal
- So insertion and removal should only occur when coagulation function is normal.
Guideline for coagulation function and neuraxial blocks in parturients with not history of bleeding problems and no significant signs or symptoms of pregnancy-induced hematoma (PIH), and not on anticoagulants
Safe to proceed
Guideline for coagulation function and neuraxial blocks in parturients with PIH, a PLT count of >100K and normal PT
PTT is required
- Make sure platelet count is not rapidly falling as it could be in HELLP syndrome.
Guideline for coagulation function and neuraxial blocks in parturients on LMWH
Follow ASRA guidelines
Consider IV analgesia
Neuraxial block and low molecular-weight heparin
If therapeutic anti coagulated, then ____
avoid block for 24 hrs
Neuraxial block and low molecular-weight heparin
If prophylactic anticoagulated, then ____
Avoid block for 12 hrs
Neuraxial block and low molecular-weight heparin
Remove catheter at least ____ after last dose
12 hrs
Neuraxial block and low molecular-weight heparin
Do not administer LWMH until ____ after block is placed or catheter is removed
2-4 hrs
Neuraxial block and low molecular-weight heparin
T/F
Avoid concurrent NSAIDs or anticoagulants
True
Signs and symptoms of epidural hematoma
- Bilateral leg weakness
- Incontinence
- Absent rectal sphincter tone
- Back pain
If epidural hematoma suspected pt must what diagnostic test?
Stat CT or MRI
For a full neurological recovery to occur from a epidural hematoma, surgical decompression must occur within ___?
6 hrs
Why should you use a new bottle of 10% iodine to prevent epidural abscess?
A bottle can become colonized after single use
If a epidural abscess occurs, how long will take for symptoms to present? What are the typical symptoms?
- 4-10 days
- Pain, loss of function
What is the treatment fo epidural abscess?
- Antibiotics
- Laminectomy
Have 6-12 hr window before permanent damage occurs
What is the presentation of epidural abscess?
- Severe back pain that is worse with flexion, sometimes radiates
- Exquisite local tenderness
- Fever, malaise, meningitis-like headache with neck stiffness
- Increased WBC, Increased ESR, positive blood culture
- Progression over hours-days to neuro deficit or osteomyelitis
Why is the epidural space very resistant to toxicity?
- Very vascular
- Intact membrane b/w it and subarachnoid space
Give examples of drugs that have been given via epidurals with poor results
- Thio
- Ephedrine
- Oxytocin
- Atropine
- Zantac
- KCl with not permanent sequelae
What is a rare complication of giving 11.25% KCL in the epidural space?
- Permanent paraplegia
What is Transient Neurological Symptoms (TNS)?
- Pain and dysesthesia in buttocks, legs, calves that can follow a SAB
- Resolves w/i 72 hrs
What is the most common cause of TNS?
Lidocaine spinals
What two factors are mostly associated with TNS?
- Lithotomy position
- High doses of concentrated lidocaine (5%)
Where is the conus located?
T12 - L3
How does needle trauma occur?
- Hitting cord with a small needle causes significant pain but if needle immediately withdrawn usually no permanent sequelae
- Injecting into the cord will have bad outcomes
Lesson is do not do regional blocks on sleeping patients
What are the two causes of compression injuries?
Lithotomy stirrups- compress the common peroneal nerve
Lithotomy position- femoral nerve and obturator nerve
What is the severity of compression injuries?
Range from transient injury to axonal crush
How long does it take to recover from compression injuries?
2-6 days if mild
2-3 years if severe
what are two examples of compression injuries?
Postpartum foot drop:
- Either common peroneal nerve from stirrups or brow compression of lumbosacral trunk
Femoral or Obturator neuropathy:
- 25% bilateral lithotomy of fetal head compression
- Femoral will have difficulty climbing stairs
- Obturator will have decreased sensation over upper inner thigh, weak hip adduction
When is the onset of PDPH?
How long do they last without intervention?
12-48hrs after dura puncture
few days to few weeks
What 2 principle determinants of a PDPH occurring?
- Size of dura hole
- Type of needle used
Larger gauge and cutting edge needles increase PDPH incidence.
What is the normal volume of CSF?
How much CSF is produced daily?
- 150cc
- 450cc made daily
What is the mechanism of PDPH?
- 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.
- Cerebral vasodilation may also play a role.
PDPH risk factors
- Younger age
- Larger needle gauge
- Cutting-edge Quincke spinal needle
- Cephalad or caudal orientation of Quincke needle
- History of PDPH or migraines.
Risk factors for dural puncture with epidural needle
- Experience (Increased risk in training)
- LOR technique (Decreased risk with saline vs. air)
- Fatigue and haste (Increased risk overnight)
- Accuracy of audit (Cases lost to follow-up)
Comparison of needle size and chance of 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
Why are pencil point needles superior in regards to preventing PDPH?
Pencil point needles significantly better than cutting tip needles because dura fibers are not cut but just pushed apart
What is hallmark differential diagnosis sign of a PDPH?
The hallmark of a PDPH is continuous head pain when patient sitting or standing that is completely or almost completely relieved by laying flat.
Other than the classic sitting up/laying down of PDPH, what other symptoms might patients with PDPH experience?
- Neck stiffness
- Tinnitus
- Photophobia
- Diplopia (rarely)
**What is the most common cause of periopertaive headache?
** Caffiene withdrawal**
This was the only part of the lecture that was in bold
What are some other problems that mimic PDPH?
This is long slide. Let me know if you it broken up
Pneumocephalus: Seen with LOR to air that injects intrathecal, headache almost instant and of short duration (hours).
Tension headache: Very common
Migraine headache
Caffeine withdrawal: Most common cause of perioperative headache!
Meningitis: fever, nuchal rigidity and si/sx of systemic illness.
Sinusitis: Look for sinus tenderness, recent URI, nasal discharge.
Cortical vein thrombosis: Rare, throbbing HA, not relieved by bed rest, may have SZ, diagnosed by CT or MRI, no clear treatment beyond symptomatic mgmt.
Subarachnoid Hemorrhage: Rupture of an AVM may occur at any time during peripartum period. Look for focal neurological signs.
Subdural hematoma: Related to Arnold-Chiari malformation- Patient will look much sicker and will usually have focal signs and change in LOC
What is the Arnold-Chiari malformation?
- Condition where lower brainstem portions are displaced caudally
- Some cases will show symptoms of brainstem compression other cases are subclinical
What is an anesthesia consideration for parturients with Arnold-Chiari malformation?
In these patients leakage of CSF even through a small dural puncture (caused by 25 ga needle) can cause the brainstem to shift downwards causing headaches and focal neurological signs.
In rare cases traction can tear blood vessels and cause subdural hematoma.
What some sequelae of untreated PDPH?
- Chronic headache
- Permanent impairment
- Convulsions d/t cerebral vasospasm
- “Coning” and brainstem death
What are all the non-invasive treatments for PDPH?
- Bed rest (Most headaches resolve by w/in 1 week)
- IVF hydration (Typically ineffective)
- Abdominal compression/binders (Impractical / ineffective)
- PO, IV, epidural analgesics (NSAIDs, acetaminophen, opioids)
- Cerebral vasoconstrictors (PO, IV caffeine, theophylline, sumatriptan)
- ACTH (Unproven, may reduce need for EBP by 50%)
The most common I’ve seen in the ER for PDPH is IVF, pain meds, and caffeine
What is the definitive treatment for a PDPH?
Epidural blood patch (EBP)
How are epidural blood patches performed?
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.
How long does it take before a patient experience relief with a epidural blood patch?
- Instantaneously!
- Resolution of the headache is nearly instant and sustained 80% of the time.
- A repeat increases the success rate to about 90%.
What are the risks with a blood patch?
- backache is the most common problem (according to Nagelhout)
- Risk are same as with regular epidurals
- Risk of infection possible, but rare
What is prophylactic blood patch?
- Basically a blood patch given thru epidural catheter, incidence of headache 10-21%
- Controversial as there has been a case report of total spinal anesthesia after a prophylactic patch
- 25% of academic centers do prophylactic blood patch
How does an EBP work?
- Clotting factors in blood help seal the hole in the dura
- The mass effect of the blood compresses the CSF giving nearly instant relief
- Try to inject at the same level as the initial dural puncture!
- Blood will spread a few levels however.
High or Total spinal anesthesia involves what 3 symptoms?
- Hypotension
- Dyspnea
- Aphonia
What are causes of High or Total spinals?
- Migrated epidural catheter
- Unrecognized dural puncture
- SAB after failed epidural
- Rarely, cerebral hypoperfusion from sympathectomy causes loss of consciousness.
Management of a total spinal
- Place patient in LUD and Trendelenberg
- Early resuscitation, ventilation, and circulatory support
- Epinephrine may be needed
- Naloxone for intraspinal opioid
- Intensive maternal and fetal monitoring
- Maintain maternal sedation (Anesthesia or sedation is usually required for 1-3 hrs)
- Urgent C-section?? (Not mandatory. Based on fetal assessment after maternal stabilization..)
If a total spinal does occur, how long should you maintain maternal sedation?
1-3 hrs
Does the OB population have a higher or lower incidence of difficult airway?
Higher
Anesthetic precautions for difficult airway in the OB population
- Have smaller tubes ready to go and short laryngoscope handle.
- If you anticipate airway difficulty make sure your regional is working or do awake fiber optic intubation.
- Beware aspiration!
Besides physiological problems, why is it important to beware of aspiration in OB patients?
Accounts for 1/3 of anesthetic lawsuits in obstetric population
You should suspect aspiration with what 3 associated problems?
- Hypoxia
- Pulmonary edema
- Bronchospasm
Steps/actions to prevent aspiration in OB patients
- 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
- H2 blockers (famotidine, ranitidine):
Metoclopramide (Reglan)
What is MOA of sodium citrate?
How long does it take to work?
Works within minutes to raise gastric pH
- lasts 30 min
How long does it take H2 antagonists to work?
Take at least 30 min to work
What is the MOA of Reglan?
How long does it take to work?
Dopamine antagonist which acts on intestinal tract via release of acetylcholine (this increases gut motility and facilitates gastric emptying)
- Requires 40-60 min.
What is the 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
