Pain, Sedation, Back Pain

Question 1

What are the 2 main descending tracts of the SC which modulate pain?

Located where?

Answer 1

Serotonergic and noradrenergic

Midbrain (Periaqueductal gray and LC) and medulla (NRM and NRG)

Question 2

What opioid receptor causes respiratory depression and miosis?

Answer 2

Mu 2

Question 3

What are the opioid receptors?

Answer 3

Mu, Kappa, Epsilon, Gamma (all beta-endorphin)

Delta - Enkephalin

Question 4

Why is Meperidine no longer used in the ED?

Metabolized how?

Answer 4

Its active metabolite - normeperidine causes CNS toxicity w/half life of 12-16h and blocks muscarinic receptors —> causes anti-cholinergic syndrome including agitation, delirium, seizure, psychosis

Via CYP 450

Question 5

Why does fentanyl work so fast?

Onset and duration?

Metabolized how?

Potential SE?

Answer 5

Highly lipophilic

1-2 minutes, 30-60m

P450 into inactive metabolites

Muscle rigidity —> treat with Narcan then NMJ blocker

Question 6

What is Vicodin?

What other brand name?

Answer 6

Hydrocodone/acetaminophen

Norco

Question 7

MOA of tramadol?

Metabolized how?

Most serious SE?
Common SEs?

Answer 7

Weak Mu agonist, also has some serotonin and NE reuptake

CYP 450

Lowers seizure threshold
N/V, dizzy, ortho HoTN

Question 8

Tramadol use with SSRI, MAOIs, SNRIs can cause what?

What is the normal dose of tramadol?

Answer 8

Serotonin syndrome

37.5mg

Question 9

When does hepatic toxicity occur in Tylenol overdose?

What is the toxic metabolite?

What is protective?

Answer 9

> 10g in 24h

NAPQI

Glutathione

Question 10

How do NSAIDs promote GI bleed and stomach irritation?

Answer 10

inhibits COX1 in stomach which is responsible for production of bicarbonate and mucous production

Question 11

How do NSAIDs effect Lithium?

Answer 11

Enhance reabsorption —> increased Li levels causing toxicity

Question 12

What muscle relaxer can be used for back pain?

Works how?

Answer 12

Diazepam 5mg tid or Lorazepam 1mg bid

GABA presynaptic inhibition at Spine cord level

Question 13

What is the analgesic dose of ketamine?

Answer 13

.1 to .3 mg/kg IV

Question 14

What does EMLA stand for?

What is in it?

Used for what?

Answer 14

Eutectic Mixture of Local Anesthetics (Eutectic refers to mixtures that result in a MP higher than that of either agent alone)

Lidocaine, procaine in an alkaline oil mixture

Veni/artpuncture, LP, arthrocentesis

Question 15

What is the dose of Ketofol for PSA?

Answer 15

Start at .75 mg/kg over 15-30s then repeat .375 mg/kg after 1-3 minutes

Question 16

IV dose of Ketamine for PSA?

IM?

Answer 16

1-2 mg/kg

4-5 mg/kg

Question 17

IV dosing of Versed for PSA?

Answer 17

.05 mg/kg

Question 18

What pt populations should ketamine be avoided in?

What can help with salivary secretions?

Answer 18

CAD/CV disease (bc it inc HTN and tachycardia via catecholamines), open globe injuries bc it inc IOP

Glycopyrrolate .01 mg/kg given 10 minutes before

Question 19

Propofol dosing for PSA?

Answer 19

.5-1 mg/kg (use 1) then titrate with .25-.5 mg/kg aliquots

Question 20

How to use Fentanyl for PSA?

Answer 20

2 (preferred) - 3 microgram/kg given BEFORE sedative agent (versed)

For deep sedation do 1-2 micg/kg

Question 21

MC Side effect of Etomidate?

Answer 21

Myoclonus

Question 22

What questions to ask for in history w/CC of back pain?

Answer 22

Work history
Meds - anticoagulants, steroids (infx/compression)
Hematuria - ruptured AAA

Question 23

What is normal PostVoid Residual (PVR) volume?

Pathologic?

Answer 23

Less than 30

> 100