ICL 7.3; Acute Post-Surgical Pain

Question 1

what are the psychological and physiologic effects of untreated pain?

Answer 1

1. increase morbidity and mortality
2. compromise recovery
3. increase incidence of chronic pain

Question 2

what are the ASA Pain Task Force 2012 Guidelines?

Answer 2

1. when possible, use a multimodal approach = opioids are supplemental treatments after you’ve used NSAIDs!
2. non-opioid treatment plans like local anesthetic or NSAIDs
3. opioids are supplemental treatments like IVA PCA, neuraxial opioids

Question 3

what usually causes acute pain?

Answer 3

acute pain normally occurs after surgery

in a sample of 1490 surgical inpatients more than 85% experienced pain

after orthopedic, general, or cardiac surgery, 63% of patients experience pain resolution within 6 days but that means 37% continue to have pain

Question 4

what is preventive analgesia?

Answer 4

attenuating central sensitization resulting from painful insults and subsequent inflammation

it has a lot of effectiveness and duration of analgesic intervention because it is clinically relevant in blocking noxious stimulus and decreasing sensitization to pain

intensive multimodal analgesic intervention is needed for effectiveness

interventions should be maintained into the post-operative phase in addition to the intraoperative phase

Question 5

what is multimodal analgesia?

Answer 5

using two or more analgesic agents that exert effects via different mechanisms and ideally act synergistically

this was introduced > 15 years ago to allow for early ambulation, improve rehabilitation, hasten recovery, and reduce hospital length of stay

strong evidence for use of local anesthetics, acetaminophen and NSAIDs because this reduced opioid use!

Question 6

what are the two types of systemic analgesics?

Answer 6

1. opioids (IV PCA pump)

2. non-opioid analgesics

Question 7

what is the MOA of opioids?

Answer 7

main effect of analgesia is from agonism at mu-opioid receptors found in both the central nervous system and peripheral nervous system

Question 8

what are the side effects of opioids?

Answer 8

adverse effects of nausea, vomiting, pruritus, ileus, respiratory depression, addiction

Question 9

how can you give opioids?

Answer 9

Subcutaneous, PO, IV, IM, intranasal, transmucosal, neuraxial

Usually oral or parenteral delivery ideal post-operatively

Question 10

what is the receptor physiology of opioids?

Answer 10

you can develop tolerance and sensitization to opioids which leads to increased dose requirement for similar analgesic effectiveness

Question 11

what is patient controlled analgesia?

Answer 11

ideal for delivering medications to patients

it compensates for variability in analgesic needs, serum levels, nursing/staff delays

these safety mechanism through biofeedback (respiratory monitoring)

they’re programmable because there’s a demand dose, lockout interval and basal infusion rate

Question 12

what are the pros of a PCA pump?

Answer 12

1. superior postoperative analgesia
2. improved patient satisfaction
3. decreased risk of pulmonary complications
4. decreases demand on nursing staff
5. no change in opiod consumption, cost or length of hospital stay or adverse opiod related effects

Question 13

what’s the conversion of dose between parenteral and oral route of opiod administration?

Answer 13

parenteral dose is always less than the oral dose

everything gets converted into terms of oral morphine

ex. morphine: parenteral dose is 10 mg and the oral dose is 30 mg

Question 14

which drugs are non-opioid analgesics?

Answer 14

1. NSAIDS and Acetaminophen
2. ketamine
3. gabapentin and Pregabalin
4. muscle Relaxants
5. topical Agents

Question 15

what are fentanyl patches used for?

Answer 15

NOT recommended for acute pain

Question 16

what is the MOA of NSAIDs and acetaminophen?

Answer 16

Inhibits COX enzymes which reduces prostaglandin synthesis

they inhibit mediation of hyperalgesia and inflammation

Question 17

what are the pros of NSAIDs over opioids?

Answer 17

decrease opioid consumption

improve post-operative pain

Question 18

what are the cons of NSAIDs?

Answer 18

1. GI bleeding
2. renal dysfunction
3. inhibition of platelet aggregation

Question 19

what is the MOA of ketamine?

Answer 19

NMDA-receptor antagonist

so it attenuates the central sensitization to pain

Question 20

what are the pros of ketamine over opioids?

Answer 20

Reduce opioid use and side effects

No respiratory depression from ketamine

Question 21

what are the cons of ketamine?

Answer 21

1. hallucinations, cognitive impairment

2. sympathetic stimulation = increased heart rate so for a cardiac patient this would be horrible

Question 22

what is the MOA of gabapentin and pregabalin?

Answer 22

inhibits α2δ subunit of voltage-dependent calcium channels

shown promising early results in lowering pain scores

Question 23

which drugs are muscle relaxants?

Answer 23

1. baclofen
2. tizanidine
3. cyclobenzaprine
4. methocarbamol

Question 24

when should you use topical pain relief medication?

Answer 24

when there’s pain in focal area

may take 3 days to 2 weeks to work

do NOT use when there’s skin irritation

Question 25

which medications are topical pain relief?

Answer 25

1. Lidocaine patch or cream 2. Diclofenac gel 3. Capsaicin cream

Question 26

what are neuraxial and peripheral analgesia?

Answer 26

Better analgesia than systemic opioids continuous administration allows for decreased adverse events, improved patient outcomes ex. epidural infusion or peripheral nerve blocks

Question 27

what are the pros of neuraxial and peripheral analgesia?

Answer 27

Longer duration than single injection Superior to systemic opioids Decreased pulmonary, cardiovascular, gastrointestinal complications in high-risk patients/procedures Outcome dependent on: Catheter location Surgical incision site Type of analgesic regimen (sole method or multimodal) Local anesthetic +/- Opioid is superior to Opioid alone Premature discontinuation of epidural may thwart its overall benefit

Question 28

what are regional analgesia?

Answer 28

Variety of peripheral regional techniques used for postoperative pain control, reducing side effects Can be in the form of single injection or continuous infusion with a perineural catheter Largely performed using ultrasound and/or nerve stimulation

Question 29

what are some of the nerve blocks people can use for pain relief?

Answer 29

1. Brachial Plexus Blocks 2. Lower Extremity Blocks 3. Truncal Blocks

Question 30

what are the different brachial plexus blocks?

Answer 30

1. Interscalene Block 2. Supraclavicular Block 3. Infraclavicular Block 4. Axillary Block 5. Intravenous (Bier) Block

Question 31

what is an interscalene block?

Answer 31

C4-C7 block which blocks superior and middle trunks (can spare the inferior trunk) useful for - Shoulder and upper arm procedures misc – concomitant ipsilateral phrenic nerve block

Question 32

what is a supraclavicular block?

Answer 32

blocks trunks and divisions of brachial plexus, but misses dorsal scapular nerve useful for upper arm and hand procedures but not shoulder however, highest risk of pneumothorax....

Question 33

what is an infraclavicular block?

Answer 33

blocks cords of brachial plexus useful for elbow, forearm, hand procedures (especially for patients who cannot abduct shoulder) most stable site for a perineural catheter!

Question 34

what is an axillary block?

Answer 34

most common; blocks terminal branches of brachial plexus in the axilla; this is NOT involving the axillary artery useful for elbow, forearm, and hand procedures (with supplemented blocks) additional block of musculocutaneous is required for most procedures

Question 35

what is Bier block?

Answer 35

an intravenous block the whole upper extremity is exsanguinate = there's no blood in the whole arm then you inject IV anesthetic in the arm which diffuses through the vein to the nerve endings from the tourniquet down to the fingers if the tourniquet fails though, the local anesthetic can go to the rest of the body and cause seizures or cardiac toxicity....

Question 36

what are the lower extremity blocks that you can do?

Answer 36

1. Lumbar Plexus Block 2. Femoral Nerve Block 3. Fascia Iliaca Block 4. Sciatic Nerve Block

Question 37

what is a lumbar plexus block?

Answer 37

Blocks the L1-L4 spinal nerves that become the iliohypogatric, ilioinguinal, genitofemoral, lateral femoral cutaneous, femoral, and obturator nerves Uses – hip joint surgeries, most knee surgeries Misc – high-risk procedure with potential for epidural spread, hematoma, local anesthetic toxicity, nerve injury, unilateral sympathectomy

Question 38

what is a femoral nerve block?

Answer 38

you block the femoral nerve Uses – surgeries around the knee Misc – can make ambulation difficult and suboptimal

Question 39

what is a fascia iliaca block?

Answer 39

Anterior block for peripheral nerves arising from lumbar plexus Uses – hip and knee procedures

Question 40

what is a sciatic nerve block?

Answer 40

Can be used as adjunct to femoral/lumbar plexus blocks Can be blocked subgluteal or at popliteal fossa levels Useful for posterior leg and coverage of the majority (minus saphenous nerve) of the lower leg and foot

Question 41

what are the different truncal blocks you can do?

Answer 41

1. Paravertebral Block 2. Interpleural Block 3. Intercostal Block 4. Transversus Abdominis Plane Block

Question 42

what is a paravertebral block?

Answer 42

Most effective of the truncal blocks Analgesia via direct somatic/sympathetic/epidural blockade Effective for thoracic, breast, and upper abdominal surgeries, and rib fracture pain

Question 43

what is an intercostal block?

Answer 43

provide relief for duration of local anesthetic but there's a high risk of pneumothorax

Question 44

what is a traverses abdominis plane block?

Answer 44

reduces pain and opioid requirements after abdominal surgery requires high volume 15 ml or more on each side