• copper (stabilizes temperature) 
• out of the circuit-exhaled gas doesn’t go back through vaporizer 
• concentration-calibrated=variable bypass- varies the amount of oxygen that flows over anesthetic
• flow over –oxygen flows over anesthetic to vaporize  
• temperature compensated-if room temp is hot, component expands to reduce oxygen that flows over anesthetic (as temp goes up, there is more vaporization) 
• oxygen flow rate independent-does not change output % isoflurane with change in oxygen flow
• agent specific-must be specific for anesthetic used
• high resistance

1. open- no rebreathing

2. semi-open- no rebreathing

3. semi-closed- partial rebreathing

4. closed- complete rebreathing

• Ca(OH)2.
• NaOH-speeds up process
• KOH-speeds up process

• inspiratory disk raises from negative pressure
• expiratory disk raises from positive pressure

• 200-300mL/kg/min for non-rebreathing
• 30mL/kg/min in circle system

• dry, cold gas-->hypothermia
• hi flow O2-->lots of wasted vaporized anesthetic = $$$ more 
• pollution

• open mouth
• TMJ mobility-don’t induce without knowing you can open the mouth!
• cervical spine mobility

§  patent airway

§  prevent aspiration, esp in ruminants

§  positive pressure ventilation

§  problematic positioning (ophthalmic)

§  upper airway disease as in bulldogs 

§  mask not possible

§  route for tracheal suctioning

• red rubber
• PCV
• silicone
• metal
• Cole
• reinforced
• PCV without writing (Sheridan YAG)

which endotrach tubes can damage mucosa with ischemia?

•   palpate neck for two tubes 
•   squeeze bag and watch chest and abdomen
• no condensation in tube
•   watch bag
•   Capnography (CO2)

•  esophageal intubation
•  CV changes
• aspiration
• hypoxemia/hypoventilation
• laryngospasms
• intraocular pressure
• intracranial pressure
• trauma/hemorrhage
• endobronchial intubation-only one sided ventilation!
• biting tubeàaspirating foreign body

•  endobronchial intubation with movement
• accidental extubation
• bronchospasm-rare
• kinking of tube
• mucus thickened, blood clot obstruction
• herniation of the cuff with older tubes-goes in front of the beveled edge and obstruct airway
•  fire with laser surgery
• compression of tube lumen instead of trachea expanding, obstructs tube

•  bitten endotrach tube-WATCH THEM DURING RECOVERY
• overinflate cuffàtracheitis, tracheal tear (esp in cats)
• subcutaneous emphysema
• dysphonia

• brachycephalics-wait even after swallowing, challenge them to prove independent breathing
• dogs and cats-swallowing
• horses: taped and kept until horse is up

o   ↓secretions

o   bronchial dilation

o   ↑anatomic and physiologic dead space

§  nares, bronchia, trachea

o   ↓GI motor and secretory activity

o   ↓vagal influence in HR

•    ketamine also a sympathetic stimulant, increases O2 use by myocardia, so atropine will stress heart.  can just use gauze to clean mouth

o   anti-muscarinicàmore NEàblock parasympathetic tone. increase HR. decrease vagal response.

o   for bradycardia and hypotension that is not alleviated by reducing anesthetic. bradycardia will get worse before it gets better.

o   phenothiazines

§  acepromazine

§  chlorpromazine

§  levomepromazine

o   butyrophenones

§  droperidol

                    § azaperone 

o   potent sedative and anxiolytic

o   cheap

o   anti-emetic

o   anti-arrhythmic properties (decreases sympathetic tone, blocks α receptors)

o   ↓dose requirement of other drugs

o   enhances analgesia of opioids

• boxers
• hypotension, post-anesthestic comatose
• look at the medical records to see if it's been given before

§  ↓ BP and vasomotor reflex

§  cardiac depression

§  peripheral α1-adrenergic blockade

§  relaxation of vascular smooth muscle

§  vasodilator (caution with brain, renal (potential for hypotension), hepatic failure (potential for hypotension))

§  persistent or permanent penile paralysis-in horses 1/10k stallions and geldings-so use an α2 in horses!!!!

§  blocks both α1 and 2, but α1 is more predominant

NOT REVERSIBLE

o   inhibits inhibitory first, then excitatory,  so initial excitation, so give slow and mix with others to inhibit excitatory first.

o   anxiolytic

o   sedative

o   muscle relaxant

o   anticonvulsant

            o   anterograde amnesia

• midazolam is water soluble, diazepam is lipid soluble
• midazolam can be mixed with other drugs
• midazolam is more potent
• diazepam is longer acting
• both cross BBB and placental barrier

zolazepam

EXPENSIVE, and needs to be used in days (Efficacy drops off)

o   anxiolytic

o   sedative and muscle relaxant

o   analgesia

o   ↓ADH binding

o   ↓insulin release

o   hypertension followed by hypotension

o   reflex bradycardia

in a young pregnant yorkie, you want to increase the heart rate during surgery. the drug of choice is:

a. atropine

b. acepromazine

c. glycopyrrolate

d. epinephrine

e. lidocaine

in what type of patients should acepromazine be avoided?

a. cardiac

b. brain occupying lesions

c. acute renal

d. hepatic failure

e. all of the above

thiopental. wakes up quickly due to redistribution. 

it is cumulative, so repeated doses until threshold where patient wakes up from elimination instead

o   splenic engorgement (capsule is α-related, relaxation, engorgement)

o   CV-myocardial depression

§  decrease in CO

§  decrease in BP

§  àincrease HR

§  bigeminal rhythm (VPC followed by sinus rhythm)

o   respiratory:

§  decrease in Vt

§  hypoventilation (rise in CO2), not necessarily hypoxia

·         minute ventilation (resp rate x tidal volume)

·         shallow breathing

§  apnea

o   neurologic

§  decrease CMR02

§  decrease ICP

§  protective for brain ischemia

§  treatment for seizures

§  decrease EEG activity

sloughing of skin if given perivascular due to alkaline pH 

sighthounds very sensitive

o   “seizure like activity”-propofol induction, gas is taking over, redistribution, excitatory, looks like seizures 10-15 min after induction

o   give benzos if this happens.

not a seizure

o   decrease in BP, CO, SVR

o   apnea

o   contains egg lecithin

§  contamination

§  6 hours, no more than 24 hours shelf life

o   cardio

§  symp stim

§  ↑HR and BP

§  careful in HCM (avoid)

§  may ↑IOP

o   respiratory

§  apneustic breathing

§  apnea

§  maintained laryngeal reflexes and PaO2

o   neurologic

§  ↑ICP and CBF

§  somatic analgesic (must use others)

·         can help with windup pain

§  excitement at emergence

·         motor activity

·         sensitivity to touch

·         violent recovery

o   clinical effects

§  ↑salivation and mucus

§  poor muscle relaxation

§  reflexes are maintained

§  rough recoveries (due to poor relaxation)

o   cardio: similar to ketamine due to symp stim

neuro: maintained reflexes (cough, swallow, corneal) 

o   ADRENAL SUPPRESSION (addisonian crisis, septic patients)

can use in sick patients,

reversible

shortacting (fentanyl)

steroid anesthetic

lower histamine release

the extent of muscle relaxation in ketamine/telazol is:

what about etomidate?

Advantages

1.      better/faster control of anesthetic depth

2.      animal gets oxygen, ventilated via intubation

Disadvantages

1.      hi cost

2.      waste gas

1.      masking inductions

2.      box induction (opening the chamber)

3.      hi oxygen flow without adequate scavenging

4.      recovery area-need hi flow in recovery area to min pollution

no more than 2ppm

if you can smell it, then it’s >2ppm

a.      acidotic (↓pH, pCO2, HCO3),

b.      hypothermia

c.       old patients

d.      sick patients (sepsis, GDV, etc)

e.       pregnancy

f.        drugs: sedatives/tranquilizers, analgesics, inducting drugs

a.      hypernatremia

b.      hyperthermia

the inhalant % achieved = 

and means:

(saturated vapor pressure/Atm pressure) x 100

(Atm=760mmHg at sea level)

means how much will be produced if just open container

time constant= volume to fill/rate. to speed it up, use a small bag or an increased rate

↓time constant= ↓capacity/↑flow

blood solubility-blood:gas partition coefficient (how much goes into blood vs gas) blood/gas

sevoflurane 0.6 

a.      rapid induction,

b.      quick change in level of anesthesia,

c.       quick recovery 

a.      longer to saturate blood,

b.      hard to maintain hi alveolar concentration

• CV: arrythmogenicity (rank: halothane, methoxyflurane, then iso/sevo)   
• ALL depress CV/pulm in a concentration-dependent manner
• use MAC sparing drugs!  (opioids, lidocaine, ace, hydromorphone, etc)

• pneumothorax (lots of nitrogen in room air infiltrating thorax, nitrous oxide travels to air pockets, exacerbates pneumos.
• harder to scavenge
• danger of hypoxic gas
• abuse potential (whip-it)
• bone marrow depression

what steps should be taken with apnea?

what should NOT be used?

• ·         call for help
• ·         check pulse
• ·         ventilate (2-3 breaths per minute)
• o   apneic threshold (graph)
• o   anesthetic pushes threshold to right, needs higher PaCO2 to spontaneously ventilate. do not wait for the animal to breathe spontaneously. allow O2 to be delivered and CO2 to accumulate.
• dopram should not be used, as it is inconsistent and stimulates the CNS

§  long procedure

§  overinflated cuff

§  mucus, pus

•  exaggerated movement-think obstruction
•  squeeze bag-easy to inflate lungs? then no obstruction. good to check at beginning for baseline. shouldn’t need a lot of pressure to inflate the lungs.
• change endotracheal tube when in doubt, may need to use suction to clear tube
• use reinforced endotracheal tube if the neck needs to be flexed

§  hypoventilation

·         ↓resp rate (but can be normal and still be hypercapnia)

·         ↓tidal volume

·         ↓minute ventilation

·         ↑PaCO2 and PetCO2

§  obesity contributes (also might wake up on table)

§  abnormal positioning

§  main culprit is inhalant

§  exhausted soda lime

§  non-rebreathing system

·         O2 flow not fast enough to remove CO2

• 50mmHg squeeze bag from time to time
• >60mmHg- ventilate

• 70mmHg-squeeze
• >80mmHg-ventilate

• most anesthetics
• shock
• blood loss
• deep anesthesia

·         any doubt: reduce vaporizer setting! if at good plane of anesthesia
·         fluids!  increase preload
·         10ml/kg over 10 minutes (maintenance rate given over shorter time)
o   fluid boluses
·         positive inotropes- ↑contractility
o   dopamine-acts on β1 receptors –CRI
§  3-20μg/kg/min
o   dobutamine-pure β1 agonist (horses)
§  0.5-5μg/kg/min
o   ephedrine-mixed β1 and α
§  0.01-0.2mg/kg

what is this, and what do you do?[image]

• VPC
• causes: hypoxemia, hypercapnia, cardiomyopathy, traumatic myocarditis, GDV, electrolyte imbalance
• tx: lidocaine- look at overall picture (perfusion of animal, BP). bc literature disagrees on numbers (5-15VPC’s per min). when in doubt, give it.
•  unifocal-may not need to treat right away
• multiform VPC (different shapes and sizes) –treat ASAP
• runs of VPC’s, look over one minute
• if lidocaine doesn't cut it, (ventricular bigeminy or ventricular fibrillation), go to procainamide

what is this and what do you do?

[image]

• sinus bradycardia
• cats<100bpm
• dogs <50-60bpm
•  causes: oculocardiac reflex
• abdominal exploration
• laryngeal stimulation
• hypothermia
• opioids
• tx: manage underlying problem
• atropine (quicker) or glycopyrrolate (slowly developing ones)

what is this and what do you do?

[image]

• second degree AV block
• P wave without QRS
• due to high vagal tone
• if HR is low also, give anticholinergic (atropine or glyco)

what is this and what do you do?

[image]

• sinus tachycardia
• >180bpm dogs

• >200bpm cats
• >75bpm horses
•  causes: light anesthesia
•  if not light: hypovolemic shock, sepsis, hypercapnea
• manage underlying problem, check blood gas
• turn up gas or analgesic (unless due to pheochromocytoma or hyperthyroidism, then use β-blocker)

• causes: loss of body temp regulation, reduced periph vasoconstrictor tone, large SA in relation to mass, nonrebreathing (cold air), surgical exposure of tissues and body cavities, IV cold fluids, coold operating room, wet drapes, excess clipping, scrub with alcohol
• prev/tx: use heated water blankets, admin warm fluids, avoid excessive clipping/alcohol scrub, keep room temp >70F, monitor body temp, lavaging with warm solutions

o   well ventilated

o   quiet

o   minimal traffic

o   controlled intensity of light

o   has supportive O2 available

o   crash cart

o   heat source

o   soft surface, especially for horses to prevent neuropathies/myopathies, pull lower front leg forward

o   sternal recumbency with head higher (to prevent regurg) in small ruminants/camelids

o   person for monitoring!

o   turn off vaporizer, turn up O2 (remove inhalants from patient and machine)

§  can worsen hypothermia

o   HR, BP, RR, ETCO2, mm, temperature, etc. still monitored

o   disconnect fluids

o   leave catheter in unless fractious

o   apply heat and dry

o   wait for swallow

§  deflate cuff and remove tube

·         monitor resp, pulse, monitor temp (every 30 min until normothermic)

·         horses- disconnected from everything, IV catheter kept, decrease inhalant concentration as much as possible. neosynephrine up nostrils-(phenylephrine) vasoconstriction. towel over eyes. secure endotrach tube to horse,  injection (missed it),  watch for horizontal nystagmus, restrain, check bilateral nasal flow

1. ventilatory
2. CV
3. hypo/hyperthermia
4. regurgitation/gastroesophageal reflux
5. delayed return of consciousness
6. emergence dysphoria

o   drug overdose/residual

o   deep plane of anesthesia

o   hypothermia

o   hypoglycemia

o   hypotension

o   decreased drug metab (cardiac, liver, kidney patients)

o   CNS disease

o   hypoventilation

o   tx: PE, monitor, circulatory shock check, cerebral injury check 

o   weak pulse

o   tachy (compensatory phase)/bradycardia (decompensating)

o   CRT>3 sec

o   cold extremities, cyanosis, hypoxemia, pale mm, hypotension

o   tx: supplement O2, fluids, dopamine/dobutamine, lidocaine, antisedan (atipamezole)

• airway obstruction
• central depression of ventilation (opioids)
• hypoxemia or hypercapnia
• stimulation of respiratory centers (hyperthermia/pain)
• failure of neural control (herniation of cerebellum/medulla)

o   esophagitis, strictures, aspiration pneumonia

o   lower head immediately, cuff well-inflated, suctioning contents, lavage with tap water, extubate with still partially inflated cuff to remove any aspirated material

• can be due to full μ-agonist opioids, benzodiazepines, or ketamine
• excitation or hysteria
• vocalization or whining
• violent, uncoordinated movements or padding
• disorientation
• restlessness or pacing
• dilated pupils
• inability to console or calm patient
• determine if  pain or dysphoric
• can give sedative (ace; dexmedetomidine if does not respond), treat for pain
• can give reversal (naloxone, butorphanol, flumazenil)
  

• ↑cardiac workload/  ↑myocardial O2 consumption 
•  catecholamine-->neutrophil suppression-->delayed healing
• hypoventilation
• ileus/decreased gastro motility
• water retention, changes in body fluid balance
• excitation/violence/self-mutilation

1. distraction
2. systemid opioids
3. NSAIDS
4. tranquilizers/sedation
5. nerve blocks, regional analgesia, wound diffusion catheters
6. cold compress
7. epidurals
8. acupuncture
9. transcutaneous electrical nerve stimulation

• analgesics used preop/intraop
• how painful patient appears
• how painful procedure appears to be
• analgesics available
• does mentation/ambulation need to be observed as part of postop?
• critically ill or can't otherwise show pain behavior?
• cardiopulm function compromised?
• how quickly patient needs to return to function
• chronic pain or wind-up?

DO2=CaO2 x CO

• oxygen delivery = oxygen content and cardiac output
• where CO= blood pressure/vascular resistance               
• and oxygen content= ([Hb x 1.34]x % saturation) + 0.003 x PO2)

·         macro-circulation

o   capnograph

o   BP

o   ECG

·         micro-circulation

o   mm

o   lactate

o   urine output

• red 660nm light- absorbed= deoxyhemoglobin
• infrared 920 nm light=saturated (oxyhemoglobin)
• Beer's law

§  vasoconstrictive patient

§  low pulse pressure

§  anemia

§  dyes

§  icterus

§  motion

§  dyshemoglobins

§  external light sources

1. bicarb (60-70%)
2. bound to proteins (20-30%)
3. dissolved in plasma (5-10%)

arterial CO2

ABG (arterial blood gas)

label the four phases: 

[image]

[image]

or A-B phase 1

B-C phase 2

C-D phase 3

D-E phase 0

o   Q=BP/SVR (systemic vasc resistance)

§  high BP does not mean good blood flow

§  vasoconstrictors will increase BP, but can decrease Q, and vice versa

§  blood pressure does not equal perfusion

what is this (lower image in art waveform), and what could be the cause?

[image]

pulse alternan.

LV failure, alternating SV, cardiac tamponade

what is this (art wave), and what could be the cause?

[image]

pulse paradoxus

hypovolemic, IPPV (intermittent positive pressure ventilation)

·         fluids-not a great sense of how much you need.

o   preload monitoring

·         inotrope

·         decrease inhalants

• hi CVP is overload,
• low CVP-water column drops with hemorrhage
• normal 0-12cmH2O
• not that accurate!!!
• pulse pressure variation

septic abdomen

also prognostic and therapeutic value

•  prone to hypoxia
•  distress (catecholamine)
•  prone to obstruction
•  (pulm edema)
•  airway obstruction after pre-oxygenation- takes longer to get to danger zone

o   avoid increase in O2 demand, avoid apnea

o   PREOXYGENATE

o   low dose opioid

o   propofol-one of fastest

o   assist ventilation

o   capnograph, pulse ox, blood gas

o   patient  position

o   mitral valve disease-want them to be vasodilated, tachycardic.

o   most anesthetic agents depress CV

§  exception is etomidate

o   low sodium, low volume

o   avoid arrhythmic agents

o   avoid vasoconstrictors

o   etomidate and low inhalant delivery

• avoid tachycardia and vasodilation
• stiff ventricle, poor diastolic function
• left ventricle outflow tract obstruction (LVOT), walls touch each other and has no space
•  worst LVOT (need to correct/avoid following):
• tachycardia
•  ↑contractility
• vasodilation- sudden wall collapse with pressure drop
•  NO KETAMINE, use dexmedetomidine instead

• do the Chem profile!
• BUN
• protein
• use reversible drugs that don’t act on liver
•  short acting drugs
• opioids, midazolam
• propofol
• remifentanyl (only opioid which is destroyed by blood instead of liver) + isoflurane
•  fluid: FFP, hetastarch, glucose

o   head trauma

o   ↑ICP

§  drugs

§  positioning

§  vomiting (opioids), cough, gag

§  CO2, O2, BP

§  Cushing’s reflex-LOW HR, HI BP

·         previews hi ICP and herniation.

o   avoid, vomiting

o   ↑ICP KETAMINE AND HALOTHANE

§  ketamine only induction with analgesic properties, so need to use something else for analgesia

• promote renal blood flow (prone to hypotension!)
• dopamine, acepromazine, fluids
• opioid (maybe not morphine), low dose ace
• Telazol ok.
• avoid NSAIDS
• dopamine CRI- INCREASE CONTRACTILTY- positive inotrope
• some vasodilation to kidney
• o   fluid therapy
• o   low inhalants
• o   ketamine in cats  with renal disease- can’t break down , lasts longer

• disease: GDV, impaction, acute abdominal crisis
•  inhalants depress resp
• surgical events: blood loss, ascites, drying exposed tissues

Na<132mEq/L

·         ADH release from stress

·         some fluids with dextrose (not LRS)

·         ruptured urinary bladder (water resabsorbed)

·         signs

o   depressed, weak, inappetant, hypotension

·         tx

o   for severe: hypertonic saline 3% or 5%

o   if you correct rapidly, then myelin sheath will disrupt

1. fix prior to anesthesia
2. preserve CO at all costs
3. chronic fluid loss needs to be corrected slowly

Na>155mEq/L

·         hypertonic saline

·         evaporation from serosal cavity during surgery

·         diabetes insipidus

·         water deprivation

·         signs

o   CNS depressions, seizure, stupor, coma, dementia

·         tx: fluids low in Na, hi in water (with dextrose)

·         correct slowly,

o   chronic 2-3 day correction

§  cerebral edema if not corrected slowly

K <3.3mEq/L

·         K –poor fluids like 5%dextrose, 0.9%NaCl

·         GI losses (v/d)

·         metabolic alkalosis

·         furosemide

·         signs

o   altered ECG

§  small p wave

o   ileus

o   muscle weakness

·         LRS 4mEq/L K. so may need to add potassium chloride in sick patients

·         speed limit 0.5mEq/kg/hr

·         no increase in dysrhythmias with chronic levels of 2.6-3.5mEq/L

o   so not a lot of need to correct during anesthesia unless patient is sick; can use a pump.

K >5.5mEq/L

·         acidosis

·         iatrogenic

·         renal failure

·         tissue trauma (cell damage)

·         main concern: dysrhythmias

o   ECG

§  no p wave

§  tall t wave

§  bradycardic, wide QRS-idioventricular rhythm-EMERGENCY

·         tx

o   0.9%NaCl to dilute

o   if acidotic-bicarb

o   insulin and 5%dextrose

§  drive potassium back into cell, prevent hypoglycemia

o   calcium gluconate if idioventricular rhythm, ecg changes (to raise normal threshold)

·         tigers are susceptible

·         ↓peripheral perfusion

·         renal failure

·         diarrhea

·         DM

·         tx

o   treat underlying problem

o   bicarb

o   correct base deficit (equation in notes)

o   different correction for younger animals

·         abomasal displacement

·         vomiting

·         iatrogenic

·         hypokalemia, hypochloremia

·         tx

o   treat underlying

o   saline

o   fluid L=% dehydration x BW

·         patient is losing water. animal will develop hyperglycemia (mild). if arrests, the worst neurologic injury. once metabolized by liver, just delivering water, can drown patient and doesn’t help perfusion. only use when needed in:

o   DM

o   insulinoma

o   pediatric

o   replace 3:1 loss if <20% of blood volume, give crystalloid

o   1:1 if using colloid when >20% loss of blood volume.  (e.g. hetastarch, hypertonic saline)

• dog: 8%BW 80ml/kg
• cat: 6%BW 60mL/kg

1. spontaneous
2. assisted
3. controlled

o   CV

§  forced gas in: great vessels are compressed. alters BP

§  cardiac tamponade-constricting movement of heart

§  ↓right ventricular outflow, ↓pulm blood flow

o   resp

§  ↑anatomical dead space

§  alveolar rupture

o   acid-base

§  respiratory alkalosis and acidosis due to inappropriate settings

·         resp depression

o   drugs

o   inhalants

·         brain tumor

o   ↑ICP

o   CO2↑, then ICP↑ further during anesthesia as more blood is diverted to brain

·         cardiac arrest

·         diaphragmatic hernia

·         drugs like atracurium-paralysis of diaphragm

·         obese

·         preggers

·         emaciated

·         thoracotomy-loss of neg pressure

·         tidal volume

o   small animals 20ml/kg

o   large animals 15ml/kg

o   10ml/kg normally

·         I:E ratio

o   always set inspiratory less than expiratory time. usually 1:4

·         peak inspiratory pressure

o   highest pressure during inspiratory phase 10-30cm H2O

o   higher in horses (closer to 30, up to 40cm H2O)

• do nothing
•             hyperventilate (lower CO2, decrease stim for breathing)
•             neuromuscular blocker
•             opioids (fentanyl)
•  rhythmic lung inflation (Hering-Breuer reflex)

• decrease resp rate 
•             decrease tidal volume
•             allow rebreathing of CO2
•             add CO2 to inspired gas

·         morphine and fentanyl. the more you give, the more side effects

·         stable in solution

·         enzymatic degradation (liver)

·         no p=aminobenzoic acid metabolite

o   lidocaine

o   bupivacaine

o   mepivacaine

o   ropivacine

o   EMLA (ecstatic mixture of local anesthetic)

·         unstable in solution

·         metabolized in plasma (cholinesterase enzymes)

·         p-aminobenzoic acid metabolite (allergic reactions)

o   cocaine

o   benzocaine

o   procaine

o   tetracaine

o   lipophilicity

o   pKa 

o   concentration

o   dose + volume

o   proximity to nerve

o   type of nerve

o   vascular effect

o   tissue blood flow

o   vasoconstrictor

o   dose

o   affinity to Na+ receptor

o   lipophilicity

§  strongly binds, fibrillation is not reversible, so obviously never IV

• midway between ribs
• cranial to rib

femoral compartmental block

psoas major

L4-5