Regional Anaesthesia Flashcards
BMJ retrospective review showed what benefits with epidural/spinal anaesthesia?
Mortality reduced by 1/3, odds of DVT reduced by 44%
PE 55%, Transfusion 50%, less MI/Renal failure/pneumonia
-weakness, did not compare to GA
In hip fx surgery (regional vs general), findings?
- Sympatholysis (vasodilation), blood thinning effect
- Decreased post op DVT (30% vs 47%)
- Decreased MI/pneumonia/Fatal PE/Hypoxemia
All of the following are true regarding major knee surgery and return to normal function EXCEPT?
A) better pain at rest and with movement with a block
B) better post op knee movement with a block at 3 mo
C) Faster return to sport at 6 mo with a block
D) Improved knee flexion at 1 mo post op with a block
FALSE statement is C: faster return to sport at 6 mo with a block
- pt w/out block more likely to meet criteria to return to sport at 6 months
- ? quad weakness from femoral nerve block (ACL surgery)
GI benefits of regional aana
Less post op ileus
improved bowel function
improved microcirculation and sympatholysis
All the following are true regarding the effect of regional anesthesia on cancer recurrence after oncology surgery EXCEPT:
A) Choice of anesthesia could affect cancer cell survival and mets
B) Morphine promotes angiogenesis
C) Local anesthetics stimulate NK cells
D) Epidural use improves 5 yr survival after colorectal resection for adenoCA
FALSE answer: D - epidural use improves 5 yrs survival after colorectal resections for adenocarcinoma
Which anesthetic drugs help cause cancer elimination via Th1 /CTL/NK cells?
- Propofol
- COX inhibits
- B-blockers
- Peripheral nerve blocks
Two concepts of cellular response in anesthesia in pts with cancer?
Elimination
Escape
What effect does morphine have on angiogenesis in cancer cells?
It increases angiogenesis
Can anaesthetic and analgesic technique affect cancer recurrence or mets?
- Evidence is inconclusive in humans
- need RCTs
All of the following are benefits of regional anesthesia in children EXCEPT?
a) profound pain relief
b) reduced nursing workload
c) longer wake up time
d) rapid discharge from PACU
FALSE answer (C) - longer wake up time
Benefits of regional anesthesia in children?
- faster wake up time, rapid PACU d/C, earlier return appetite
- profound pain relief
- reduced nursing workload, less like to remove dressings/catheters
- no risk of congitive effects as GA does
What are the effect of neuraxial blocks on surgical blood loss and transfusion requirements?
- Sympatholysis and vasodilation (decreased BP) leads to decreased blood loss
- less transfusion
Study on OR Time consumption with interscalene block (ISB)
- saved 170 euro per case
- ready for surgical prep faster
- faster emergence time (return of spontaneous breathing)
All of the following are true regarding Local anesthetics EXCEPT?
A) the work by blocking Na channels only
B) Slow rate of depolarization of nerve action potential
C) There are 2 types of local anesthetics (esters and amides)
D) Ropivacaine is less cardiotoxic than bupivicaine
EXCEPT A) work by blocking Na channels only
Benefits of regional anaesthesia?
Hight pt satisfaction
Shorter LOS
Decreased Morbidity/mortality
Two general categories of local anesthetics? Most commonly used?
Esters (dental procedures)
Amides (most common)
How are ESTER local anesthetics metabolized?
Hydrolysis by choinesterase
How are AMIDE local anesthetics metabolised?
Liver microsomal enzymes
Allergy risk of ester anesthetics?
Low, but produces PABA
Allergy risk of AMIDE anesthetics?
Very low
Mechanism of action of local anesthetic?
Blocks Na channel - Impedes cell from depolarizing (cannot reach action potential)
Blocks K+ channels, and even calcium channels
True or false, local anesthetic works in an acidic environment (like an abscess)?
False, it will not work in an acidic environment (site of an infection), as they are Bases
Half life of bupivicaine? Mechanism of action?
376 minutes
Prevents ATP from entering mitochondria
Local anesthetic maximum recommended doses in mg/kg?
Lidocaine 5 plain… 7 (with epi)
Prilocaine 6 plain… 9 (with epi)
Bupivicaine 2.5 plain… 3 (with epi)
Ropivacaine 2.5 plain… 3 (with epi)
Which drug has a better safety profile (less cardiotoxic), ropivacaine or bupivacaine?
Ropivacaine
Rate of systemic absorption?
IV > tracheal > intercostal > caudal > epidural > brachial plexus > sciatic > subcutaneous > spinal
Indications for regional anesthesia?
- moderate to severe pain -pre-existing chronic pain
- pain expected to last > 48hrs
- to avoid opioids in: OSA,IBD,babies
- extensive abdominal/thoracic Sx
Other indication for regional anesthesia?
High anesthesia risk patient, amenable to regional
- multiple comorbidities
- difficult airway
Contraindications to regional anesthesia
- pt refusal
- anticoagulation (to neuraxial, but not compressible peripheral)
- infection at the site -unknown lesion/rash
- peripheral nerve block specific (ex interscalene w diaphragm prob)
The 3 different brachial plexus blocks?
- Interscalene, supraclavicular
- Infraclavicular, axillary
- Branches
Inerscalene and supraclavicular block for what kind of surgery?
- Shoulder (bankart)
- upper Arm surgery
Infraclavicular and axillary block for what kind of surgery?
Surgery below the elbow
Branches of brachial plexus, typically for what surgery?
Surgery below the wrist
Lower extremity blocks?
Femoral/fascia iliaca: ACL repair or knee Sx
Sciatic: Foot surgeries
Truncal blocks? (3)
- TAP
- Ilioinguinal/iliohypogasric
- paravertebral
TAP block (transversus abdominal plane block), for ? (2)
Laparotomy, laparoscopy
What kind of block would you use for inguinal hernia, orchidopexy?
Ilioinguinal/iliohypogastric
Paravertebral block useful for what kind of procedures?
Thoracotomy, laparotomy, breast surgeries
SVT Tachycardia to PVC then VTACH, intra-op after 0.5% injection 5ml of bupivicaine, what kind of systemic toxicity?
Torsade des Pointes, have mitochondrial toxicity
7.5-20/10000 peripheral
1/10000 epidural
Why would local anesthetic toxicity more common in babies?
Less albumin available to bind free drug
Treatment of anesthetic systemic toxicity, as per ASRA?
ACLS
Seizure control
Specific treatment with 20% lipid bolus infusion
Cardiopul bypass activation
How does lipid rescue work ?
-Circulating free bupivicaine is bound by lipid, before it binds mitochondrial receptors
