anethesia test

thiopental sodium, methohexal sodium

ketamine, tiletamine

• route: always parenteral-usually IV
• used to maintain anesthesia: drip for short procedures
• -important to know which accumulate in the body tissues

decreased chatacholamine production

• simple to give
• little equipment needed
• more economical
• no chance of explosion or polution
• no irritation to airway

• Possibe tissue irritation-barbituates
• once given no removal or reversal agent
• depth of anesthesia not easily altered
• airway not often provided
• drug may be cumulative
• recovery-excitement/hallucinations
• induction apnea possible
• elimates throught the kidneys

• more immediate effect-drug is deposited directly into blood
• easier to titrate to final effect-occurs almost immediatly after injection
• used for drugs that are irritating to the tissues (barbituates)
• requires more restraint

• does not require as much restraint
• cant titrate to effect, can be extreamly variable between pts

only on pts that you cant access a vein: rodents neonates

• induction agents
• -allow intubation, allow maintenance w. an inhalent
• maintain anesthesia for short proceedures
• -short-acting, drugs w/ littel accumulation in body tissues
• quickly re-establish anesthetic plane
• -only if on inhalent
• increased analgesia
• -lidocaine
• -supplement to inhalent anesthesia

• blood flow to brain and other tissues of the body-lipid solubility
• distribution to and absorption by other tissues of the body
• metabolism-redistribution must happen
• elimination

• schedule III (some II)
• induction
• general anesthesia
• sedatives/hypnotics-pentobarbitol
• anticonvulsant-phenobarbitol
• euthanasia-pentobarbitol

• Short acting
• intermediate acting
• long acting

the shorter the drug action the more lipid soluble the drug

• thiopental-10 mins of true anesthesia, complete recovery w/in an hour
• ultrashort-methohexital

Pentobarbital 30mins/6hrs

phenobarbital 4hrs/15hrs

high lipid content of the brain and blood allows for immediate effect

• lipid solubility
• distribution
• onset of action
• length of effect

• depression-degree depends on dose and drug
• anticonvulsant
• excitation during induction and recovery

• Resp. depression-rate and tidal volume and response to rising CO₂
• Dose dependant relationship
• apnea-w. rapid admin or high doses

• can significantly depress CVS if given rapidly or in high doses
• directly depresses the myocardium resulting in decreased cardiac output
• increase heart senstivity to the action of epinephrine-especially in excited or stressed animals can cause dangerous arrythmias

• hypoproteinemic
• acidotic
• lean animals-sight hounds
• liver dysfunction
• renal failure
• cats

• stop injection
• keep (-) pressure on syringe while withdrawing it from pt
• infiltrate/dilute w/ isotonic saline (+/- lidocaine)
• notify veterinarian
• watch for signs of irritation (1-2hrs) sloughing (2-5 days)

• local swelling
• pain
• necrosis
• tissue sloughing
• scaring

• stage II excitement-due to extravascular inj. or subanesthetic amoutns, may be dangerous due to injury, give 1/3 rapidly then titrate
• hypothermia-slow metabolism & excretion
• Cats-more sensitive due to enzymes

• thiopental-pentothal
• methohexitol-brevital

• supplied in a powdered form
• reconstitute to 1-5% solution
• unstable shelf life (2 weeks in fridge)
• continuous admin with cause:
•    body to become saturated
•    recovery will be prolonged
• 70%-80% is bound to plasma

• causes splenic engorgement
• may not want to use for abdominal sx

• horses-use following tranquilization given iv using 5% solution
• Cattle-not used
• pigs-same as dogs or cats

• ketamine-kataset, ketalean, vetatar
• tiletemine-always combine w/ zolazapam- telazol

• disrupt nervous system pathways
• -amneasia, analgesia (only to limbs) and catalepsy
• protective reflexes may be exaggerated rather than depressed
• -difficult to assess depth
• marked sensitivity to sound and light

• provide analgesia to skin and limbs
• poor visceral analgesia
• metabolized by the liver
• renal excretion
• cannot reverse-will cause extream excitement
• could help in speeding recovery and controlling extreme post anesthetic excitement

• tissue irritation-but no sloughing
• ptyalism-drooling
• increased csf pressure
• eyes remain open, centrail and dialated

• stimulates Cardiovascular system
• -Increased HR, CO, mean arterial BP and venous pressure
• -increased O₂ consumption demand

• apneustic repiration pattern
• -inspiratory followed by prolonged pause, exhalation short hard breath
• can tap nose to encourage breathing

• Epileptogenic-seizure pt
• emergence delirium
• -vocalization, agitation, uncoordination, tranqs can help min. effects
• caution for repeated admin.
• -accumulation in tissues especially  in overweight pts increased risk of seizures PO
• metabolized by the liver excreted by the kidneys

• ace
• diazepam-most commin in sm animal
• guaifenesin-lg animal
• xylazine-lg animal (cats)
• medetomidine-fractious cats (cat magic)

Schedule III used with zolazepam-Telazol

• newer dissociative
• onset of action is more rapid and longer than ketamine/diazepam IM
• good muscle relaxation
• good induction agent in health dogs and cats
• less apneustic respiration
• variety of species, wild life immobilization

• rough recovery
• cats have prolonged recovery

diprivan, rapinovet, propoflo

• slighty water soluble-but needs to be mixed
• contains soybean oil and egg lecithin
• supports bacterial growth-once open discard w/in 6hrs
• extended use version has benzyl alcohol good for 12hrs but contra indicated in cats
• wide margin of safety

• short duration in dogs and cats
• does not accumulate-can be used CRI
• no reaction if given perivascularly
• rapid onset caused by cns uptake
• good induction agent for sight hounds
• no need for anticholenergic (may want tranq pa)
• brisk, smooth recovery
• safe w/ pts with hepatic dz and renal dz pts
• can be used to quickly reestablish anesthetic plane

• will cause dose dependant apnea and hypotension
• caution should be used if animal has cardiac preload problem (blood loss or dehydration)
• poor analgesic
• expensive
• poor storage
• may exacerbate systemic infections

• meabolized by conjugation w/ the liver playin an important role
• plasma clearance exceeds hepatic blood flow suggesting other organs may also be involved

• cns depression
• can produce resp, depression and apnea
• transient decrease in arterial BP and myocardial contractility

• titrate to effect slowly over a period of 20-60 seconds
• 1cc/5-10sec
• onset of action <60 sec
• duration 5-10 mins

• amidate
• sedative hupnotic

• not h2o soluble dissolved w. 35% propylene glycol
• may cause pain and irritation w/ iv infusions
• Rapid onset of action and rapid recovery
• single dose w/ depress adrenal fx up to 3 hrs
• may cause
• -retchin
• -apnea
• -excitement stage

• clinical dose does not effect cardiopulmonary fx
• no change in HR or BP or myocardial activity
• agent of choice for cardiac cases or animals in shock
• mild-moderate dose dependant resp. depression

• single dose 10-20 mins
• rapid hepatic metabolism/urine excretion
• no accumulation

• ideal for high risk pts
• min. cardiopulmonary effects
• rapid metabolism
• rapid recovery

• propylene glycol causes
• high osmolality of solution
• may cause iv hemolysis
• -always admin w/ fluids

combo of analgesics w/ tranq

• induce profound sedation
• used as an induction agent (not suitable for healthy pts)
• safe alternative for comp pts

• Dissociatives oxymorephone+ ace
• barbituates    oxymorephone+medetomidine

• Gecolate
• centrally acting muscle relaxant:
• -does not affect the diaphragm
• -may cause transient hupotension
• produces muscle relaxation w/o depression of resp. center
• always admin iv cath w. dextrose to help prevent hemolysis

tech of administrating anesthetic agents via the lungs

• methoxyflurane-metofane, penthrane
• halothane-fluothane
• isoflurane-aerrane, isoflo, forane
• sevoflurane-ultane sevoflo
• desflurane-suprane

• liquid anesthetic vaporized into o2
• delivered to pt by mask or ET tube
• conducted to air passege & into alveoli
• anesthetic diffueses across resp. membrane into blood stream
• rate of diffusion is contolled by:
• -gradient between the aveoli and the blood
• -tissue perfusion

• alveolar conc is high and clood conc so anesthetic moves down the gradient
• perfusion and lipid solubility allow accumulation of anesthtic in brain causing loss of consciousness

• % of anesthetic delivered
• wentilation of the pt

• blood conc, of anesthetic is high soooo
• -anesthtic moves down conc fradient from the brain and into alveoli
• -elimnated by resp
• removed by scavenge

must leave pt on 100% o2 for 5 min to create steep gradient

amount of liquid anesthetic that will evaporate at 20 degrees C and determin the type of vaporizer required

• 1. agents w/ high VP evaporate and will reach a lethad conc. of 30% in o2 delivered to the pt
• 2. anesthetics with a high vapor pressure require a precision vaporizer to limit vaporization to 5% which can still be fatal
• 3.low vapor pressure ansethetics may be safely used in a non-precision vaporizer

• Halothane (red) 244mmHg
• Isoflurane (purple) 241mmHg
• Methoxuflurane 225mmHg
• Sevoflurane (yellow) 160mmHg

measures the tendacy of the anesthetic agent to exist as a jas or dissolve in the blood

• tend to remain as a gas in the alveoli rather than dissolving in the blood and tissue, has rapid induction, depth change and recovery
• Hal-2.4%
• Iso-1.2%
• Sevo-0.6%

• dissolve readily in blood and tissues  so cause slow induction depth change and recovery
• Methoxo 12%

• minimun alveolar concentration
• lowest concentration whcih produces no response to pain in 50% of the pts exposed to painful stimuli

LOW MAC=MORE POTENT=MORE ANALGESIA PRODUCED

• Methoxy-0.23%
• Halothane-0.87%
• Iso-1.2-1.3%
• Sevo-2.4%

• MAC .87% (moderate analgesic)
• induction dose 2.5%
• maint dose 1.5%
• solubility Coef 2.4% (low)
• Vapor Press-243mmHg (precision)

• sensitized heart to catecholamine->dysrrythmia
• most pronunced during first 30 minutes

• associated w. malignant hyperthermia
• pt w/ hepatitis or lvr dz
• cardiac conditions

• Iso-forane, isoflo
• -S.C-1.4%
• -MAC 1.2-1.3%
• -Induction 2.5%
• -Maint 1.5%

• Sevo-Ultane
• -S.C 0.6%
• -MAC 2.4%
• -Induction 4.5%
• -Maint 3.5%

• Rapid induction due to low S.c's change in depth w.in 1-2min
• Rapid recovery w/in 1-2 min of turing of vap
• low rubber solubility
• high MAC so not as potent

• inhalation drug of choice for
• -cardiac pts, hepatic pts, renal pts, and neonates
• Due to elimination through the lungs
• Sevo allows cog and motor fx to return @ same time  (equine)

Sevo is expensive

• hal-50-80% from norm respirations
• iso-99% through respirations
• sevo-97% through respirations

• Hal-dec resp and Tidal volume, dose dependant
• Iso-Resp depression
• Sevo resp depression

• Hal: sever cardiac depression, decreased myocardial contration, and dysrhythmias
• Iso: min to mod effects
• sevo: min to mod effects

• Halo: sever arterial hypotension due to myocardial depression
• iso and sevo: decreases due to decrease in vascular resistance