APEX Flashcards
What is transmission
afferent pain signal travels from the peripheral nervous system to the central nervous system via a 3 - neuron pathway
During modulation, when is pain inhibited?
Spinal neurons release GABA and glycine (inhibitor NT) & the descending pain pathway release NE, serotonin, and endorphins
When stimulating an opioid receptor, what happens?
reduces NT release from presynaptic neurons and hyperpolarizes post synaptic neurons
what are the four types of opioid receptors (all are G proteins)
Mu (MOP), Delta (DOP), Kappa (KOP), ORL1 (NOP)
how does opioids produce respiratory depression?
by shifting the CO2 response curve to the right
How do opioids effect a healthy patients blood pressure?
although they reduce heart rate, opioids have a minimal effect on blood pressure in healthy patients
Define Dependence
occurs when a person taking a drug will go through withdrawal upon discontinuation of that drug
Define tolerance
occurs when a patient requires higher doses of a drug to achieve a given effect
define addiction
a disease; if a person cannot stop using a drug despite negative consequences from suing that drug, they have an addicition (substance abuse disorder)
except remifentanil, how are all opioids metabolized
hepatic biotransformation
what has to have if an opioid produces an active metabolite
may require a dose adjustment in a patient with an impaired clearance mechanism (kidney or liver failure)
Meperidine MOA
mu and kappa receptor agonist
what is meperidines active metabolite
normeperidine - by CYP450 - causes myoclonus, reduces seizure threshold, and increases CNS excitability. avoid in dialysis patients and use with caution in the elderly
when does alfentanil have such a fast onset
due to being 90% non-ionized - diffuses quickly across the patients blood-brain barrier
why is alfentanil useful in anesthesia
blunting the hemodynamic response to short, intense periods of stimulation, such as tracheal intubation or retrobulbar block
how is remifentanil metabolized
RBC and tissues esterases
following discontinuation of remifentanil, what should be of concerned
hyperalgesia
when is methadone useful
chronic treatment of opioid abuse, chronic pain syndromes, cancer patients
how does methadone decrease pain
Mu receptor agonist, NMDA receptor antagonist, and inhibits reuptake of monoamines in the synaptic cleft
when giving methadone, what ECG changes should we watch for
prolonged QT interval
what can rapid IV administration of opioid cause
skeletal muscle rigidity
if chest wall rigidity occurs, where is the greatest resistance to ventilation
larynx
why use partial agonist opioids
produce analgesia with a reduced risk of respiratory depression
when redosing what is one thing you should consider
there is a ceiling effect, beyond with additional analgesia is not possible
what is the opioid antagonist prototype
Naloxone
Naloxone dose and DOA
1-4 mcg/kg, lasting 30-45 min
what should you expect when reversing a patients analgesia
SNS activation - can cause neurogenic pulmonary edema, tachycardia, cardiac dysrhythmias, and sudden death
what is the gold standard for post operative opioid delivery
Intravenous patient-controlled analgesia (IV PCA)
factors that increase risk of respiratory depression with IV PCA
basal infusion rate, administration of other sedative medications, old age, pulmonary disease, OSA
when should a multimodal pain management approach be considered
OSA, advanced age, and opioid dependence
define sound
simply a pressure wave (form of mechanical energy) that travels in a longitudinal wave
define compression
region of high pressure - forms the peak of the sound wave, and rarefaction (a region of low pressure) forms the trough of the sound wave
define frequency
measure of pitch - tells us how many cycles occur in a given period of time; measured in Hertz
what process did we steal from bats
echolocation
piezoelectric material
transduce electric energy to mechanical energy and vice versa
how does the ultrasound transducer emit ultrasound waves
into the body at a fixed rate and then it listens for echoes between each pulse - a process that repeats many times each second
vertical dot placement
determined by how long it takes for the echo to return to the transduce
horizontal dot placement
determined by the particular crystal that receives the returning echo
how do hyperechoic structures appear
bright - produce strong echoes
how do hypoechoic structures appear
darker shade of grey - produce weak echoes
how do anechoic structures appear
black - they dont produce any echoho
how do vascular structures appear
black circles in short-axis and black tubes in long-axis. arteries pulsate, but veins done
how do nerves appear
tend to appear anechoic (black), but distal peripheral nerves are hyperechoic (white) with a characteristic honeycomb appearance
what is resolution
ability to see two separate things as two separate things
what are the ultrasound 3 dimensional beams
axial, lateral, and elevation
where is the focal zone region
where the beam is the narrowest
examples of attenuation
absorption, reflection, scatter, and refraction
how does short axis view structions
cross section
how does long axis view structures
along its length
lower frequency wavelength
longer wavelengths - allow us to see deeper inside the body, but we sacrifice image resolution
higher frequency wavelength
shorter wavelengths - produce the best resolution at the expense of not visualizing deep structures
Linear probe
flat footprint that contains piezoelectric crystals arranged in parallel
curvilinear probe
convex footprint, and the arrangement of the piezoelectric crystals inside follows suit
phased array probe
very narrow in the nearfield and fans out with i creasing depth
what does gain allow you to do
adjust the strength of the returning echoes desplayed on the screen
what does depth determin
how deep you can see in to the body
what is B mode
brightness - produces real time image of the sonoanatomy, and most bedside ultrasound procedures utilize this modality
what is M mode
time-lapse photo that ilustrates that relative movement of structures over time
describe the doppler effect
change in the perceived frequency of a sound wave when there’s realitive motion between the sounds source and an observer
red vs blue on doppler
red: positive shift - towards you
blue: negative shift - away from you
where does the brachial plexus originate from
ventral rami of cervical nerve roots C5-T1 - occasionally also involving T2
brachial plexus mnemonic - structural elements
Reach (roots) To (trunks) Drink (divisions) Cold (cords) Beverages (branches)
5 terminal branches of the BP
Most (musculocutaneous)
Athletes (axillary)
Must (median)
Really (radial)
Unite (ulnar)
How are non-terminal branches of the brachial plexus categorized
my origin in relation to the clavicle
supra vs infra clavicular
supra (dorsal scapular, suprascapular, long thoracic)
infra (lateral pectoral, medial pectoral)
what nerve root does the phrenic nerve come from
C5 - look for hemidiaphragmatic paralysis
define dermatome
describes area of skin innervated by a dorsal (sensory) spinal nerve root
define myotome
muscle innervated by the ventral (motor) spinal nerve root
define osteotome
describes bones and joints innervated by the dorsal (sensory) spinal nerve root
when is an interscalene block appropriate
procedures involving the shoulder and proximal upper arm
what transducer is appropriate for ISC
high frequency linear array
ISB landmarks
cricoid cartilage
clavicle
later border of the clavicular head of the sternocleidomastoid muscle
your patient has severe COPD and on at home oxygen, getting shoulder surgery. what block is appropriate
none - trick question
what are the indications for a supraclavicular block
upper arm, elbow, forearm, wrist, and hand
what transducer is appropriate for a superclavicular block
high frequency linear
what is the most significant complication after a supraclavicular block
pneumothorax
what are the indications for infraclavicular
procedures involving the upper arm (below the shoulder), elbow, wrist, and hand
infraclavicular landmarks
clavicle
coracoid process
what is considered the most painful BP block
infraclavicular due to the multiple muscle layers that must be traversed to accomplish
what happens if you loose your needle tip during an infraclavicular block
inadvertent puncture of the distal subclavian artery / vein
what are the indication for an axillary block
procedures involving the elbow, forearm, wrist, and hand
what are the landmarks for a axillary block
axillary artery
coracobrachialis m
pectoralis major
bicep
tricep
axillary complications
LAST
nerve injury
vascular puncture
hematoma
infection
what are the indications for a wrist block
produce anesthseia of the hand and fingers
should you use Epi in a hand block
it increases risk of ischemia when used for digital nerve block, controversial
when is a Beir block best suited
for procedures that produce minimal postoperative pain (carpal tunnel release)
what are the tow plexuses that innervate the lower extremities
lumbar plexus: L1-L4
sacral plexus: L4-S4
what are the 6 nerves that give risk to the lumbar plexus
iliohypogastric
ilioinguinal
genitofemoral
lateral femoral cutaneous
obturator
femoral (largest)
what are the 5 major nerves in the sacral plexus
superior gluteal
inferior gluteal
posterior cutaneous
pudendal
sciatic
what are the 5 nerves that innervate the foot and ankle
saphenous
sural
superficial peroneal
deep peroneal
posterior tibial
what does the lumbar plexus provide sensory and motor too
lower abdominal wall
anteromedial thigh
knee
what does the sacral plexus provide sensory and motor innervations to
gluteal region
posterior thigh
lower leg
foot
define allogynia
pain due to a stimulus that does not normall produce pain
define algogenic
a stimulus that is normally expected to produce pain
define analgesia
no pain is sensed in response to a stimulus that produces pain
define dyesthesia
abnormal and unpleasant sense of touch
define hyperalgesia
exaggerated pain response to a painful stimulus
define neuralgia
pain localized to a dermatome
define neuropathy
impaired nerve function
define paresthesia
abnormal sensation described as pins and needles
where do pain modulations occur
spinal cord
define central sensitization
the efficacy of the desceding inhibitory pain pathway is impaired
define complex regional pain syndrome
characterized by neuropathic pain with autonomic involvement
indications for thoracic paravertebral block
breast surgery
thoracotomy
rib fracturei
indications for celiac plexus block
management of cancer pain of the upper abdomen
indications for superior hypogastric plexus block
managment of cancer pain of the pelvic organs
indications for sphenopalatine block
release postdural puncture headaches
what cranial nerve is the only enveloped in a meningeal sheath and bathed in CSF
optic nerve
what risk do you run with a retrobulbar block
inadvertent local anesthetic injected into optic sheath
what is a transverse abdominal plane block (TAP)
unilateral, peripheral nerve block that target the nerves of the anterior and lateral abdominal wallind
indications for a TAP block
abdominal procedures - general, GYN, urologic - that involve T9-L1 distribution
what are the landmarks for a TAP block
external oblique
latissimus dorsi
iliac crest
TAP complications
peritoneal puncture
liver hematoma
inhibition of COX 1
impairs platelet function, causes gastric irritation, and reduces renal blood flow
inhibition of COX 2
produces analgesic, anti-inflmmatory, and antipyretic effects
MOA of aspirin
irreversibly inhibits COX 1 and COX 2
platelet inhibition lasts for the life of the platelet
define aspirin-exacerbated respiratory disease
combination of asthma, allergic rhinitis, and nasal polyps
can develop life threatening bronchospasm following aspirin administration
morphine equianalgesic to 30mg Ketorolac
morphine 10mg
is acetaminophen an NSAID
NO - analgesic and antipyretic with NO anti-inflammatory effectsis
the most common cause of acute liver fialure in the US
acetaminophen
What can a sphenopalatine block be used for
Postural puncture headache
