Simple to give Very Little Equipement Needed No explosion or pollution hazard Non-Irritant to airway
Injectable Anesthetics (Advantages)
Possible Tissue Irritation (if given outside vein) No recall of drug Depth not easily altered as a sole anesthetic Airway may not be provided Drug may be cumulative in body tissues Recovery Induction can cause apnea Elimination
Injectable Anesthetics (Disadvantages)
Mostly IV IM IP
Injectable Anesthetic (Routes)
Immediate Effect Easier to titrate to effect Good for irritant to tissues drugs (Barbiturates)
IV Admin (Reason for Use)
Requires more restraint, asepsis and skill
IV Admin (Disadvantage)
For difficult patients and/or species
IM Admin (Reason for Use)
Cannot titrate to effect
IM Admin (Disadvantage)
Only on patients that a vein isn't possible to get i.e. Rodents and Neonates
Barbituates (Class of Patients Sensitive to this type of Drug)
To Hypoproteinemic for barbituates
Stop Injection Keep Negative Pressure on Syringe while withdrawing Inject 2x volume of Isotonic Saline (0.9% NaCl) into area +/- Lidocaine for pain Notify Vet Watch for signs of irritation/sloughing (more fluid if nessecary)
Barbituates (Steps to Take incase Admin outside vein)
Local swelling Pain Necrosis Tisssue sloughing Scaring
Barbituates (Signs that occur after perivascular injection)
Stage II Excitement Hypothermia
Barbituates (Side Effects)
give 1/3 rapidly then titrate to effect (apnea at first)
How to avoid stage II excitement phase while giving barbituates?
Thiopental (Pentothal) Methohexital (Brevital)
Most common barbiturates used in vet med for induction of anesthesia?
Thiopental (Brand Name)
Comes in a powder form Reconstitutes 1-5% solution Has an unstable shelf life
Splenic Engorgement (not good for abdominal sx) Contraindicated for hypoproteinemia
Pentothal (Side Effects)
False: Body becomes saturated with drug, revovery prolonged
True or False: Thiopental (Pentothal) is good for TIVA?
Used following Tranquilizer/Alpha 2 agonist
Thiopental (Pentothal) (Use in Horse)
Not Satisfactory- Too much fat
Thiopental /Pentotal (Use in Cattle)
Similar to Dogs and Cats
Thiopental /Pentotal (Use in Pigs)
Disrupt Nervous System Pathways
Cyclohexamine (Mode of Action)
Sensitive to Sound and Light Difficult to assess anesthetic depth Cannot reverse Tissue irritation Poor Visceral Analgesia Ptyalism (Drooling)
Significant analgesia to skin and limbs Helps in speeding recovery
Epileptogenic, Emergence Delirium, Not for repeated administration (TIVA or re-establishing anesthetic depth)
Apneustic repression which leads to hypercapnia which leads to resp. acidosis
Respiratory effects of Cyclohexamine
Birds, horses and exotics
Ketamine used for induction in
IV can be given IM or "orally" in fractcious animals
Routes of Ketamine induction
2-6 hours for healthy pt. (approx. 5-10 min of anesthesia)
Duration of Ketamine
Increased salivation Pain with IM injections Vocaliazation/Delirium/Seizing during recovery Not for head trauma pts
Disadvantages of Ketamine (4)
True- Schedule III
True or False Ketamine is a scheduled drug?
eliminate unwanted side effects produce good skeletal muscle relaxation
Ketamine often used in combo to
Ket/Val (Diazepam/Valium and Ketamin)
Most common Ketamine combo
GKX Guaifenesin Xylazine Large Animal, sometimes cats
Triple Drip Usually used for induction on?
Tiletamine ( Cyclohexamine) and Zolazepam (Benzodiazepine)
Telazol includes what two drugs?
Is Tiletamine (Telazol) a scheduled drug?
Onset faster Longer duration of anesthesia Good Muscle relaxation good induction agent for cats/dogs decreased apneustic respiration good for variety of species (wildlife)
Advantages of Tiletamine (Telazol) (6)
Rough Recovery which is proloned in cats
Disadvantage of Tiletamine (Telazol)
Propoflo, Rapinovet Cyclohexamine
Propofol Brand name/class
Soybean oil and egg whites which makes it cross the BBB fast because of its lipid solubilty
Propofol is made up of
Will support bacterial growth Must discard after 6 hours (24 hours ok)
Caution with Propofol why?
Benzyl alcohol added- Lasts 28 days- heinz bodies in cats
Short duration (5-10 min) Does not accumulate (CRI, TIVA, re-establish plane) No reaction if given perivasculary Rapid Onset Good for sight hounds No need for anticholinergic Fast, smooth recovery Safe with hepatic/renal disease
Advantages of Propoflo (8)
Dose-dependant apnea and hypotension caution if pre-load issue (blood loss/dehydration) poor analgesia expensive poor storage may exacerbate systemic infections
Disadvantages of Propoflo
High bacteria pt Spleen sx (past/present) because some drug may be metabolized by spleen
Propofol may be bad for
CNS depression (Unconsciousness) May produce Resp. Depression/apnea (give slow to px) Transient decrease in arterial blood pressur and myocardial contractivity
effects of propoflo (3)
Route of Propoflo
Alfaxalone Brand name/class
similar to propoflo but less cardiovascular effects (good for CHF) Can give IM
Advantages of Alfaxalone
Cost Rough IM recovery Controlled Substance
Disadvantages of Alfaxalone
Titrate to effect- Give slowly 0.5-1 ml per 5-10 secs, wait 5-10 sec, repeat
How to administer Propoflo
Brand name/Class of Etomidate
Extreme Cardiac Cases
When would we use Etomidate as an induction agent?
May cause pain/irritation with IV infusion May depress adrenal function for up to 3 hours May cause retching, apnea, excitement May cause hemolysis (administer with fluids) Expensive
Disadvantages of Etomidate? (5)
Rapid onset (15 sec) Rapid recovery (5 min) Does not depress cardiopulmonary function (HR, BP) Rapid hepatic metabolsim no accumulation
Advantages of Etomidate? (5)
Oxy and Ace Oxy and Dexdmedetomine
Common Neuroleptanalgesia induction combos (not common but good back up plan)
Induce profound sedation Usually for high risk puts May be safe alternative
Advantages of using neuroptanalgesia for induction (3)
Not suitable for routine induction in healthy pts. (wont achieve true anesthesia)
Disadvantage of using neuroptanalgesia for induction (1)
Gecolate aka "GGG" Muscle Relaxant
Guaifenesin Brand Name/Class
Guaifenesin (Gecolate/GGE) IV
What drug is used for an adjunct to induction in equines?
Good muscle relaxant that does not affect the diaphragm or resp. center
Advantages of Guaifenesin (Gecolate/GGE)
may cause transient hypotension only use 5% (>10% irritant to body tissues and can cause hemolysis) must administer under high pressure (large amounts)
Disadvantages of Guaifenesin (Gecolate/GGE) (3)
5% dextrose, 5% Guaifenesin (Gecolate/GGE)
5 & 5
Technique of administering anesthetic agents via the lungs
Liquid anesthetic vaporized into O2 Delivered to pt. by mask or ET tube Conducted to air passages and into alveoli Anesthetic diffuses across resp. membrane into blood stream
Inhalation Anesthesia intake into the body (4 steps)
concentration gradient b/w alveoli and blood tissue perfusion
Inhalation Anesthesia- Rate of diffusion is controlled by
% anesthetic delivered ventilation of pt
Depth of anesthesia maintained through
to create steep gradient for removal of anesthetic gas
why is it important to leave pt on 100% O2 for 5 min
the amount of liquid anesthetic that will evaporate at 20 degrees C and determines the type of vaporizer required
False- High vapor pressure evaporate readily and reach lethal concentration of 30% in O2
T/F agents with a high vapor pressure will not evaporate and is safe to leave out
To limit Vaporization to 5% (less fatal of a dose)
Why do high vapor pressure anesthetic require precision vaporizer?
-Ventilate at rate of 12-16 rpm - After appox. 3-5 min. watch pt (notice when breathing stops) - Decrease ventilation to 8-12 rpm rest of sx -Recovery= decrease ventilations at rate of 1 res. every 2-3 min.
Process of completely taking over respirations with reservoir bag
-Inspiratory pressure -Inspiratory time (I:E) -Tidal Volume -Resp. Rate
Mechanical Ventilators can control 4 things
Bird Mark 7
Pressure Cycle Ventilator common name
Pressure cycle Ventilator (Bird Mark 7) Air may leak- never reaches pressure- over inflate chest
Least safe ventilator and why?
Volume Cycle Ventilator/Ohio Metomatic
Most safe Mech. Vent.
Pressure cycle/Bird Mark 7 ventilator must set...
Volume Cycle Ventilator/Ohio Metomatic must set...
Volume Cycle Ventilator common name
Time Cycle Ventilator common name
Inspiratory time Better to control CO2 levels
Time Cycle Ventilator/Drager must set? advantage?
over ventilating may lead to
Heart Rate Heart Rhythm
2 values ECG gives
Cautery, Movement, Electric Dental Equipment, Drying out of electrodes, 60 cycle interference
True/False 1 and 2 degree AV blocks can be normal in equines
1 degree AV block
2 degree AV block Tx: Atropine
3rd degree AV block Tx: Pacemaker
T-waves should be no more than ____% the height of R-wave
Myocardia Hypoxia Tx: Ventilate
Broadened and Heightened T-wave indicates Tx:
Electrolyte Imbalance (beware VPC's are coming) Common in Blocked Toms Tx: Dextrose
Spiked T-waves indicate Common in? Tx? lead to?
A genetic disorder will have increased muscle activity leading to hyperthermia (under anesthesia)
-Decreased muscle activity - Decreased metabolic rate - introduction of cold gases - Sx. prep (shave, alcohol) - Opening of body cavities
Hypothermia causes (in anesthesia) (5)
-Keep something b/w pt and table (blankets, circulating water blanket) -Warm IV Fluids -Warmies -Bear hugger
4 ways to px hypothermia
no physiologic consequences
> or equal to 96 F
at what temp do we have body system depression
at what temp do we have complete body system depression aka coma?
What would the anesthetic risk be for a normal healthy patient undergoing an elective procedure? (excellent anesthetic risk)
What would the anesthetic risk be for a patient with a slight to mild systemic disease with no functional limitations, a well-controlled disease of one body system? Possibly mild to moderate obesity. (good anesthetic risk)
What would the anesthetic risk be for a patient with a moderate systemic disease that limits activity but not incapacitating, mild clinical signs. (fair anesthetic risk)
What would the anesthetic risk be for a patient with a severe systemic disease that is a constant threat to life, has at least one severe disease that is poorly controlled. (poor anesthetic risk)
What would the anesthetic risk be for a patient that is moribund and not expected to survive 24 hours with or without surgery, this would be a last ditch effort. (guarded anesthetic risk)
The absence of pain perception
What is the 4th vital sign?
Hyper excitability of central neurons due to the constant bombardment of pain signals, this creates an increased sensitization to pain
1. Wind-up 2. Amount of GA
What two things do Pre-emptive analgesics decrease?
Pain cause by a stimulus that normally does not result in pain
Increased response to a painful stimulus
1. Allodynia 2. Hyperalgesia
What two things does Wind-up lead to?
1. Opioids 2. NSAIDs 3. Local anesthetics
Name three common analgesics
The pain receptors in the brain and spinal cord
What do opioids act on?
Anxiety and vocalization
What might a dysphoric patient experience?
Will opioids produce sedation?
1. Morphine 2. Hydromorphone 3. Fentanyl
Give three examples of Opioids
What does OTM stand for?
What species is the administration of a drug via OTM most effective in?
1. PO 2. IM/SQ 3. Transdermal 4. Intraarticular
Give 4 routes of administration of an opioid
1. Analgesia 2. Anti-inflammatory 3. Antipyretic
What are the three properties of NSAIDs?
1. Somatic (musculoskeletal) 2. Visceral (organs and soft tissue)
Where do NSAIDs provide analgesia?
Prostaglandins, by inhibiting enzymes COX 1 and 2
What do NSAIDs cause inhibition of?
The production of good prostaglandins. They maintain renal blood flow, produce gastric mucus and maintain platelet function.
What are COX 1 enzymes important for?
The production if prostaglandins that cause pain and inflammation.
What are COX 2 enzymes important for?
1. Carprofen 2. Meloxicam 3. Deracoxib
Give three examples of NSAIDs
1. PO 2. Injectable
What are the two routes of administration of NSAIDs?
How long does the analgesic properties of one injection of Carprofen last?