Exam 1 Flashcards
(119 cards)
1
Q
What does an anesthesia event include?
A
Appropriate patient preparation
Preemptive, multimodal analgesia
Balanced anesthesia
Monitoring & support
• From pre-op to post-op – not just while in the OR
• Most unexpected anesthetic deaths occur in recovery
2
Q
4 phases of anesthesia
A
Preanesthesia
• Sedation & analgesia
Induction
• Smooth & rapid unconsciousness
• Dose to effect
Maintenance
• Support & monitor
• May need more analgesia
• Dose to effect
Recovery
• Support and monitor
• May need more analgesia
• Dose to effect
3
Q
ASA Status
A
o Status to decide if a patient will be safe under anesthesia
o 1-5
o 1 healthy
o 5 moribund
4
Q
10 Causes of Anesthesia Related Death
A
o ASA status o Being a cat o Small body size or obesity o Increasing age o Use of only inhalant anesthesia o Urgent procedure o Major vs minor surgery o Duration of procedure o Improper Intubation of cats o IV fluid overload in cats
5
Q
Why use pre-meds
A
o Allow decreased dose of induction & maintenance drugs
o Decrease stress for patients
o Decrease work for staff
6
Q
Sedation Vs Tranquilization
A
Sedation
o central depression, drowsiness, centrally induced relaxation
o generally unaware but can become aroused
o responsive to noxious stimulation
Tranquilization
o anxiety is relieved and the patient becomes relaxed
o remains aware
7
Q
Pros & Cons of Benzodiazepines
A
Pros • Cardiopulmonary sparring • Amnestic • Midazolam is water soluble • Mild tranquilization/ anxiolytic • Decreases MAC • Reversible with flumazenil • Good muscle relaxation • Anticonvulsant
Cons • Excitement • Effect prolonged with liver disease • Diazepam is not water soluble • Diazepam painful on IM • Midazolam is expensive • No analgesia
8
Q
Pros & Cons of Phenotiazines
A
Pros
• Good sedative
• Lower threshold for arrhythmias
• Antiemetic
Cons • Not reversible • Hypotension (α –blockade, VD) • Platelet aggregation inhibition • Long acting, especially with liver disease • Mild respiratory depressant • No analgesia • Lower seizure threshold in epileptics
9
Q
Pros & Cons of alpha-2 agonists
A
Pros • Excellent sedation • Excellent muscle relaxation • Mild analgesia • Reversible (atipamezole, yohimbine)
Cons
• Hypertension (VC, followed by hypotension)
• Reflex bradycardia and central sympathetic blockade
• Might cause emesis
• 1st, 2nd, 3rd degree AV blocks
• Stridor in brachycephalic breeds
• Depresses respiratory centers
• Diuresis, inhibits insulin, hyperglycemia
10
Q
Pros & Cons of Propofol
A
Pros • Rapidly acting • Rapidly metabolized and redistributed • No cumulative effect with repeat doses • Easily titratable • sedation • anti-convulsant
Cons • Hypotension (VD) • Respiratory depression, apnea • cardiac depression • No analgesia • May cause twitching • May cause hemoglobin oxidation in cats • IV only
11
Q
Pros & Cons of Ketamine
A
Pros • Water soluble, can be given IM • Can be used as CRI • Rapid anesthesia • Analgesic • Good anesthetic in cats
Cons • tachycardia & hypertension • Increases intracranial P & intraocular pressure • Increases salivary secretions • Not reversible
12
Q
Pros & Cons of Etomidate
A
Pros • Cardiopulmonary sparing • Hypnotic • Sparing to brain circulation • sedation
Cons • Expensive • May cause vomiting, twitching • Suppresses adrenocortical axis • May cause hemolysis • IV only • no analgesia
13
Q
Pros & Cons of Alfaxalone
A
Pros • Water soluble, IM • Rapid acting • Stable Cardiovascular • sedation • muscle relaxation
Cons • No preservative • Metabolized by the liver • Respiratory depression – apnea • Recoveries can be rough • no analgesia
14
Q
Pros & Cons of Inhalants for Maintenance
A
Pros
• Easy to change anesthetic depth
• Minimal metabolism
Cons
• Need a lot of equipment
• Dose-dependent cardiovascular & respiratory depression
15
Q
What to monitor during surgery?
A
o ECG
o BP w/ Doppler
o Pulse oximeter
o End-tidal CO2
16
Q
Why Premed?
A
o Calming o Analgesia o Smooth induction/recovery o Decrease anesthetic requirement o Decrease sympathetic response to surgery
17
Q
Acepromazine Basics
A
o Sedative with muscle relaxation o Antiemetic o Little effect on the heart & pulmonary function o No analgesic effect o No reversal
18
Q
Acepromazine Receptors Involved
A
Alpha-1 antagonist
• Vasodilation
• Decrease thermo regulation
• Serotonin block (sedation)
Dopamine 2
• Sedation
Muscarinic
• Muscle relaxation
H1
• Sedation
19
Q
Acepromazine Adverse Effects, Indications, Contra-indications
A
Adverse Effects • Decrease BP by 25% • Decrease PCV 20-30% • Decrease platelet aggregation • Priapism in stallions (prolomged erection)
Indications
• sedation and muscle relaxation
• cardiac disease patients when longer sedation is required
• with opioids and/or other sedatives
Contra-indications
• Not effective in cats
• Liver issue patients
20
Q
Benzodiazepine; drugs, receptors involved, indications, reversal drug
A
o Midazolam & Diazepam
Receptors
• Enhances GABA affinity to receptor
• Inhibitory neurotransmitter
Indications • “sedation”, • anxiolytic and muscle relaxation anticonvulsant (higher dose) • very sick patients ASA IV-V • cardio compromise patients • pediatric/geriatric patients
Reversals
• Flumazenil
21
Q
Midazolam Vs Diazepam
A
Midazolam
• Anxiolytic with some muscle relaxation
• Anticonvulsant effect
• Little effect on pulmonary and cardiovascular systems
• Can be reversed
• Unreliable sedation
(Paradoxical excitation)
• No analgesia
• Water soluble
• Does not bind plastic or crystalize
• Short T1/2
Diazepam • Poorly water soluble • Binds plastic & crystalizes • Only PO or IV • Long duration in dogs & horses
22
Q
Dexmedetomidine; basics, contra-indications
A
o Alpha-2 agonist
Indications
• Sedation,
• analgesia and muscle relaxation
• When short duration sedation is needed
Contra-indications
• cardiac diseased patients
• pediatric patients
• pregnant animals
23
Q
Reversal Drugs for Alpha-2 agonists & adverse Effects
A
- Atipamezole – very Alpha-2
- Yohimbine – reverse xylazine
- Tolazoline – approved in horses
Adverse Effects
• Excitation
• Loss of analgesia
• Tachycardia & hypotension
24
Q
Xylazine; basics, onset, duration, route of admin
A
o Alpha-2 agonist o analgesia & sedation o Horse & ruminants o T1/2 30-50 mins o Onset for IM = 15 min o Doesn’t work well SQ
25
Xylazine Adverse Effects for different species
Dogs
• Decrease cardiac output & BP
• Sinus bradycardia & 2nd AV block
• Salivation, emesis, reflux
Sheep
• Hypoxemia
Cows
• Decrease rumen contraction
Horses
• Decrease GI movement
• Abortion in mares
• Increased Urinary output
26
Opioids Basics
```
o Analgesia
o sedation and muscle relaxation
o antitussive
o Cardiovascular safe
o Decreased inhalant requirement
o Reliable reversal
```
27
Ketamine Metabolism & Contra-indications
Metabolism
• liver metabolism dependent
• excreted unchanged in urine in cats
```
Contra-indications
• cardiac disease patients
• seizure patients
• glaucoma patients
• kidney disease patients
• very compromised patients
```
28
Anticholinergis; drugs, indications as pre-med drugs
o Atropine
o Glycopyrrolate
Indications
• Premed for small patients
• Bradyarrhythmia w/ low BP in emergency
• Vagus stimuli intraop
29
Atropine Vs Glycopyrrolate
```
Atropine
• IM, IV, SQ
• Fast onset
• 20-40 min duration
• cross BBB & placenta
```
```
Glycopyrrolate
• IM, IV, SQ
• Slow onset
• 1-2hr duration
• does not cross BBB or placenta
```
30
Compare Alpha-2 Agonist, Acepromazine, Benzodiazepine sedation, analgesia, reversal
Alpha-2 Agonist
• Sedation
• Analgesia
• Can reverse
Acepromazine
• Sedation
• No analgesia
• No reversal
Benzodiazepine
• Unreliable sedation
• No analgesia
• Can reverse
31
Kitty Magic
o Ketamine
o Dexmedetomadine
o Buprenoprhine (or some opioid)
32
Propofol Receptor, Metabolism, Excretion & indications/Contra-inidcations as induction drug
Mechanism of Action
• GABA-A agonist
• Hepatic (CYP450) + extrahepatic metabolism
• Renal + extra renal excretion
Indications
• Healthy dog or cat
• Short procedure
• Seizure/brain trauma patients
Caution
• C-section (crosses placenta)
• Greyhounds
33
Ketamine Onset & Duration
o Rapid onset of action of 1 min (IV)
| o Short duration (5- 20 min)
34
Ketamine mechanism of action, metabolism, & indications/contra-indications for use as induction drug
Mechanism of Action
• Phencyclidine-binding site antagonist at NMDA receptor
• Prevents glutamate from binding
• Metabolized by liver
Indications
• Healthy dog, cat , horse
• Short procedure
Cautions
• Kidney dz patients
• Critically ill patients
• patients with occupying lesion of brain
• Patients w/ history of seizures
• C-section (cross placenta and neonate depressed)
• Patients with severe cardiac disease
35
Tiletamine Basics
o very similar to ketamine
o Potent chemical restraint/anesthesia (IV or IM)
o With zolazepam (benzo)
o Often used w/ alpha-2 agonist
36
Tiletamine duration in dogs vs cats
dogs
• IM (10 – 30min)
• IV (7 – 27min)
• Tiletamine longer than zolazepam = rough recovery
cats
• IM (40 -70 min)
• IV (35 – 70 min)
• Zolazepam longer than Tiletamine
37
Tiletamine mechanism of action & indications/contra-indications for use as induction drug
Mechanism of Action
• Like ketamine
• Phencyclidine-binding site antagonist at NMDA receptor
• Prevents glutamate from binding
Indications
• Healthy & aggressive dogs, cats, horses
• When IM injection is preferable
Contrainidcations
• Same as ketamine
38
Etomidate Onset, duration, CRI? medicate with?
o Rapid onset IV (30 s)
o ultrashort duration IV (2 – 3 min)
o ALWAYS administered with benzo
o NO constant rate infusion
39
Etomidate mechanism of action & indications/contra-indications for use as induction drug
Mechanism of Action
• GABA-A agonist
• Liver metabolism
• Renal excretion
Indications
• Dogs & cats w/ cardiac dz
Caution
• Seizure patients
40
Alfaxalone; scheduled? CRI? Duration?
o Class IV controlled substance
o Can be used as constant rate infusion
o Duration 25 mins dogs & 45 mins cats
41
Alfaxalone mechanism of action & indications/contra-indications for use as induction drug
Mechanism of Action
• GABA-A receptor agonist
• Hepatic metabolism
• Renal excretion
```
Indications
• Healthy dog, cat
• Short procedure
• Can use IM
• Seizure/brain trauma patients
```
Contra-indications
• Horses (rough recovery)
42
When to Intubate?
o Loss of jaw tone (muscle relaxation)
o Eye position
o Decrease palpebral reflex
Eye position in cats
• Light anesthesia – pupil central
• Adequate Anesthesia – pupil rotated
• Deep Anesthesia – pupil central
43
Overview: route of admin, use for seizure patients, use for cardiac patients, CRI ability, & receptor for propofol, ketamine, etomidate, & alfaxalone; which one is good for liver patient?
```
Propofol
• Route of admin – IV
• Seizure cases – yes
• Cardiac cases – small amount
• Constant rate infusion – yes
• Receptor – GABA-A
GOOD for liver
```
```
Ketamine
• Route of admin – IV or IM
• Seizure cases – no
• Cardiac cases – no
• Constant rate infusion – yes
• Receptor – NMDA
```
```
Etomidate
• Route of admin – IV
• Seizure cases – no
• Cardiac cases – YES
• Constant rate infusion – no
• Receptor – GABA-A
```
```
Alfaxalone
• Route of admin – IV or IM
• Seizure cases – yes
• Cardiac cases – small amount
• Constant rate infusion – yes
• Receptor – GABA-A
```
44
Pressure Ares of Anesthesia Machine
```
High pressure
• 2000 PSI
• Gas cylinder
• Pressure gauge
• Regulator
```
Intermediate Pressure
• 40-55 PSI
• Flow meter
• Flush valve
Low Pressure
• 20 cm H2O
• Rest of the machine
• Patient
45
The Regulator on the Anesthesia Machine
o Decrease oxygen tank pressure to safe working pressure (40-55 PSI)
o Prevent fluctuations in pressure as the tank empties
46
The Flowmeter on the Anesthesia Machine
o Flowmeters determine the fresh gas flow FGF (mixture of gases and inhalant anesthetic agents) to the anesthetic circuit
o Amount of gas entering the tube is controlled by a flow-control knob & needle valve
47
The Vaporizer on the Anesthesia Machine
```
o Liquid anesthetic -> vapor
o Meter to measure amount of vapor leaving vaporizer
o Agent-specific
o Variable-bypass
o Flow-over the wick
o High-resistance (or plenum)
o Temperature compensation
```
48
Desflurane Vaporizer
o Desflurane require special vaporizer due to high
volatility
o Vaporization process = reduction in temperature
o Vaporizer is electrically heated to 39 C
o Providing an external heat source compensates for significant heat loss associated with desflurane vaporization
49
The Common Gas Outlet on the Anesthesia Machine
o Leads from anesthetic machine to breathing circuit
50
Oxygen Tank Duration Calculation
o (Remaining PSI x full tank capacity (L)) / full tank PSI = L of O2 left
51
Basics of Breathing Systems & Two Types
* Deliver O2 and anesthetic to the patient
* Prevent significant rebreathing of CO2
* Control ventilation
* rebreathing or non-rebreathing
52
Basics of a Rebreathing System & Flow Rate
* Circle system
* Flow rate greater than metabolic oxygen consumption
* flow rates below 1000 mL/min should not be used
* WSU uses 1 to 2 L/min for most of the patients connected to a rebreathing system
53
Uni-directional Valves on Rebreathing System
* permit gas flow in one direction
* inspiratory valve opens during inspiration
* expiratory valve opens during expiration
54
Tubing on Rebreathing System
• Made up of a corrugated plastic
• Y-piece
Coupled to the endotracheal tube
OR
Universal F circuit
o Coaxial system reduces bulk associated w/ breathing system
o Warms inspired gas w/ expired gas
55
Reservoir Bag on Rebreathing System
* Compliant reservoir of gas that changes volume with the patient’s expiration and inspiration
* Recommended volume = 5–10 times the patient’s normal tidal volume (10–20mL/kg)
56
APL Valve & Pop-Off Occlusion Valve on Rebreathing System
APL Valve
• commonly referred to as pop- off valve
• Allows excess gas to escape from circuit
• Normally should be left fully open at all times unless positive pressure ventilation is used
Pop-Off Occlusion Valve
• Allow temporary closure of outflow to the scavenger system
• Facilitate easy and safe manual intermittent positive pressure ventilation
57
CO2 Absorbants
* base (absorbent) neutralizing an acid (CO2) = water, a carbonate (e.g., calcium carbonate) and heat
* Granules turn from white to purple or pink as they become exhausted
* Color change should not be used as the only indicator of absorbent exhaustion
* Look for evidence of both heat and moisture within the canister
PH indicators
o Ethyl Violet (purple)
o Phenolphthalein (red)
58
Pros & Cons of Rebreathing System
```
Pros
o Economical
o Less environmental contamination
o Better maintenance of body temperature
o Preserve moisture of the inspired gas
```
Cons
o Difficult spontaneous breathing for small patients
59
Basics Of Non-Rebreathing System
* Absence of unidirectional valves and CO2 absorber
* Depend on high fresh gas flow rates to flush CO2 from the circuit
* Not used for patients exceeding 10kg
* O2 flow rate = 130-300mL/kg/min
* Waste Gas Scavange System
60
Two Types of Waste Gas Scavenge System
Active
o Uses slight vacuum
Passive
o Does not use negative pressure
o Has activated charcoal canister
61
Mechanisms of Inhalation Anesthetics & Common Types
* Most are organic compounds, except N2O
* Isoflurane is the most used in North America
* sevoflurane is second
* Halothane is no longer in North America
Mechanism
o Not understood
o No specific receptor
o Enhance inhibitory channels & attenuate excitatory channels
62
What is Vapor & Vapor Pressure?
Vapor
• Gaseous substance that is liquid at ambient temp & pressure
Vapor Pressure
• pressure that vapor molecules exert when liquid and vapor are in equilibrium
• Measure of the ability of the anesthetic to evaporate
• Temp of liquid is increased = more molecules escape to liquid phase
63
Solubility of Anesthetic Gases
o Solubility in blood and body tissues determines rate of uptake and distribution w/in body
o Primary determinant of speed of anesthetic induction and recovery
o Most commonly expressed as a partition coefficient (PC)
64
Anesthetic Gas Effects on the CNS
o Reversible, dose-related CNS depression
o Decrease cerebral metabolic rate
o No change or increase in cerebral blood flow
65
Anesthetic Gas Effects on the Respiratory System
o Depress respiratory
o Decrease ventilation in a drug & species specific manner
o Detection of arterial CO2 depressed
66
Anesthetic Gas Effects on the Cardiovascular System
o Dose-dependent decrease of CO
o Dose-dependent decrease of arterial BP
o Decrease in vascular resistance = vasodilation
67
Anesthetic Gas Effects on the Kidneys
o Decrease in renal blood flow & GFR
o Influenced by hydration state during anesthesia
o IV fluids maintain renal blood flow
68
Minimum Alveolar Concentration (MAC)
o concentration of inhaled anesthetic within the alveoli at which 50% of subjects do not move in response to a surgical stimulus
o potency is inversely proportional to MAC
o low MAC decreases side effects
69
Factors that Decrease MAC
```
o Injectable anesthetics or pre-anesthetics that cause CNS depression
o Patient in critical condition
o Hypothermia
o Pregnancy
o Old age
```
70
Nitrous Oxide
o One of 1st inhalants
o “laughing gas”
o MAC reduction is about 20-40%
o To avoid hypoxemia deliver 50-75% of the inspired breath
o Check pulse oximeter
o 100% oxygen should be given during recovery for about 3-5 minutes to prevent hypoxia
o Increases intracranial pressure
o Potency in most animals studied is half (or less) than that found for humans
71
Pathologic Pain
o So much pain that all movement is eliminated
72
Consequences of Pain for Cardiovascular, Pulmonary, GI, renal, Extremities, Endocrine, CNS, Immune
Cardiovascular
• Tachycardia, hypertension, vasoconstriction
Pulmonary
• Hypoxia, hypercarbia, atelectasis
GI
• Nausea, vomiting, ileus
Renal
• Oliguria, urine retention
Extremities
• Limited mobility, thromboembolism
Endocrine
• Vagal inhibition, increased adrenergic activity, increased metabolism
CNS
• Axiety, fear, sedation, fatigue
Immunologic
• Immunosuppression
73
Transduction & Peripheral Sensitization
o Inflammation
o Nociceptors respond only to noxious stimuli
Peripheral Sensitization
• Increased nociceptor sensitivity = hyperalgesia
• A-beta fibers usually used for touch sensation transmit pain signals
74
Modulation & Central Sensitization
o Spinal cord
o Complex
o Normal pain signal transmitted to the ipsilateral side of the spinal cord & up the ascending tracts to the brain
Central Sensitization
• Amplification of pain at spinal cord = allodynia
• More pain impulses sent to brain
75
Why Pre-emptive Analgesia?
o Receptors in dorsal horn of spinal cord become ‘upregulated’ from painful impulses = ‘central sensitization’
o Preemptive analgesia decreases input to or response of these receptors
76
Why Use CRIs & Drugs for CRI
Why Use a CRI
o More stable plane of anesthesia
o Lower dose of any drug needed = less side effects
o Easy to change dose
o Decreased cost for tech time, & supplies
```
Drugs for CRIs
o Opioids
o Lidocaine
o Ketamine
o Alpha-2 agonists
o Any combo!
```
77
Precautions for Opioids
```
o Vomiting
o Slowed GI
o Sedation in dogs & ruminants
o Excitement in horses & cats
o Respiratory depression
```
78
Buprenorphine & Butorphenol
Buprenorphine
o Partial mu agonist
o Long duration
o Minimal sedation
```
Butorphanol
o Mu antagonist, kapp agonist
o Moderately potent
o Short duration
o Very sedating
```
79
Precautions for Local Anesthetics
o High dose related side effects
| o CNS & cardiac signs w/ overdose
80
Onset & Duration of Lidocaine, Ropivicaine, Mepivicaine
Lidocaine
o 2min onset
o 90 min duration
Ropivicaine
o 5-10 min onset
o 4hr duration
Mepivicaine
o 5 min onset
o 2-3hr duration
81
Onset & Duration of Bupivicaine & Liposome Encapsulaed Bupivicaine
Bupivicaine
o 1-10 min onset
o 4hr duration
Liposome Encapsulaed Bupivicaine
o 10 min onset
o 72hr duration
82
Anti-inflammatory Drugs Peri-operatively; basics & precautions
o Treat source of pain
```
Precautions
• Can cause or exacerbate…
• Nausea, vomiting, anorexia
• Renal dysfunction
• Hepatic dysfunction
• GI ulcers
• Clotting dysfunction
• Serious adverse effects VERY rare
```
83
Alpha-2 Agonists Peri-operatively; basics & precautions
o Medetomidine and dexmedetomidine
o Xylazine, detomidine, romifidine
o Both sedation AND
analgesia
o Effects are reversible
Precautions
• Not appropriate for those w/ cardiac dz
• Vasoconstriction -> increased BP -> compensatory bradycardia
84
How to use Ketamine Peri-operatively; basics & precautions
o Blocks ‘wind-up’ or central sensitization
o Part of multi-modal therapy
o Must be administered as constant rate infusion (CRI)
Precautions
• None at CRI dose!
• If overdosed = excitement & tachycardia
85
Tramadol Peri-operatively; Basics & bioavailability in dogs Vs cats
• MAYBE appropriate as part of MULTIMODAL therapy. Not alone.
Only slightly bioavailabile in dogs
• Analgesia probably due to serotonin/reuptake inhibition,
• only mild analgesia
Bioavailability cat: 93%
• Potentially more effective in cats than dogs
• Cats REALLY don’t like the taste
86
Zorbium
long-acting
trans-dermal
analgesic
87
Solensia
osteoarthritis med made for cats
88
Abnormal Mucus Membrane Colors
```
o Brick red = toxemia
o Muddy (brownish) = methemoglobinemia
o Grey = vasoconstriction
o Yellow = liver
```
89
Locations to Listen to Heart
Mitral valve
• L side
• 5th intercostal space
• ventral
Pulmonic Valve
• L side
• 3rd intercostal space
• ventral
Aortic Valve
• L side
• 4th intercostal space
• center
Tricuspid Valve
• R side
• 4th intercostal space
• ventral
90
Hypotension Vs Hypertension
```
Hypo
• Systolic P <80mmHg
• Mean P <60mmHg
• Mild = 45-60mmHg
• Severe = <45mmHg
```
Hyper
• Systolic P >160mmHg
• Diastolic > 100mmHg
91
Common & Less Common Issues w/ Heart Rhythm in Anesthetized Patients
```
Common
• Sinus arrhythmia
• Bradycardia
• Sinus Tachycardia
• VPC’s
• AV conduction block
```
```
Less Common
• AV dissociation
• Ventricular Bundle branch blocks
• Atrial fibrillation
• Ventricular tachycardia
• Ventricular fibrillation
• Asystole
```
92
Electrocardiography (ECG)
o Diagnose arrhythmias or conduction abnormalities
o Heart rate
o Rhythm
o Normal or abnormal P waves (1 for every QRS)
93
Invasive BP Monitoring
o Aneroid manometer OR electronic transducer
o System must be “zeroed” to atm pressure
o Periodically flushed with saline
o ONLY mean arterial pressure
Arterial catheter placement
• Dorsal pedal (dog/cat)
• Facial, transverse facial or great metatarsal
(horses)
• Auricular artery (ruminates/swine)
94
CVP
o Evaluate cardiac function & fluid load
o Normal = -3 to +5 cm H2O
o Increase to 10cm H2O -> potential fluid overload
o Read at end of expiration
95
Normal HR in Dogs, Cats, Horses
Dogs
• 100 – 160 bpm (miniature or toy breeds)
• 60 – 100 bpm (medium, large breeds)
• 120 – 160 bpm (puppies up to 1y)
Cats
• 140-220 bpm
Horses
• 24-40 bpm
96
Normal CO, Systolic P, Mean P, Diastolic P, & CVP in Dogs
```
o Cardiac output: 150-180 ml/min/kg
o Systolic AP: 100–140mmHg
o Mean AP: 70–100mmHg
o Diastolic AP: 50–90mmHg
o CVP: -3 to +5 cm H2O
```
97
Crystalloid Fluids
```
o “Balanced electrolyte solutions”
o Water-based solution with small particles
o Ex.: Na, Cl, K, Mg, glucose
o Only 25 % remain intravascular
o Tonicity
```
98
Colloid Fluids
```
o Water-based with large particles – ≥50.000 daltons
o Does not cross normal capillary
o Long lasting effect
o Synthetic and natural
o Ex: whole blood and plasma, Vetstarch
```
99
LRS; basics, indications & contraindications
```
o isotonic
o Buffer – lactate
o liver metabolism
o Na+, Cl-, K+, Ca++
o Only fluid that has Ca++
```
Contraindications
• Do not give with blood products
• Do no give in cases of hyperkalemia
Indications
• correct dehydration and maintenance
100
Plasma Lyte-A; basics, indications & contraindications
o isotonic
o Buffer – acetate and gluconate
o muscle metabolism
o Na+, Cl-, K+, Mg+
Contraindications
• cases of hyperkalemia
Indications:
• correct dehydration and maintenance
101
0.9% NaCl; basics, indications
o Isotonic
o No buffer
o Na+ and Cl-
Indications:
• correct
dehydration and maintenance;
• supplement Na and Cl
102
Hypertonic 7.5% NaCl; basics, indications, adverse effects
o Hypertonic
o No buffer
o Higher concentration Na+ and Cl-
o Short duration (1h)
Indications:
• rapid increase of blood volume
• decrease ICP
```
Adverse effects:
• do not use in kidney dz
• hypernatremia,
• hyperchloremia
• temporary metabolic acidosis
• dehydration;
• worsen uncontrolled bleeding
```
103
5% dextrose; basics, indications
o Hypotonic
o No Buffer
o Just glucose metabolized into water
Indications:
• correct intracellular dehydration
• glucose supplementation
104
Vetstarch; basics, indications, adverse effects
o Buffer - 0.9% NaCl
o Longer duration than 7.5% NaCl
o Longer storage time
Indications:
• increase oncotic pressure
(hypoalbuminemia)
Adverse effects:
• circulatory overload
(titration);
• coagulation disorders;
• anaphylactic reactions (rare)
105
What to do if your patient is hypotensive under anesthesia
o First turn down/off vapor anesthetic
If no response ->
• Bradycardia -> atropine
• Decreased contractility -> ephedrine, doputamine, dopamine
• Vasodilation -> ephedrine, dopamine, phenylephrine, etc
106
Correct Bradycardia or Decreased Contractility During Anesthesia
* Beta 1 adrenoreceptor agonist
* Atropine, dobutamine
* Fast action as CRI
* Dose-dependent
107
Correct Vasodilation During Anesthesia
* Alpha 1 adrenorecptor agonist
* Dopamine, phenylephrine
* Fast action as CRI
* Dose dependent
108
What is Considered Hypertension & How do you treat it under anesthesia
o Systolic P > 160mmHg and/or
o Diastolic P > 100mmHg
Treatment
• Analgesic
• Sedative
• Vasodilators (acepromazine, clevidipine, nitrossprusside)
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Acepromazine, Clevidipine, & Nitroprusside for Treating Hypertension
Acepromazine
• Alpha-1 antagonist
• Arteriolar & venodilator
• Long lasting
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Clevidipine
• Ca2+ channel blocker
• Arteriolar dilation
• Short acting
• Rapid onset as CRI
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Nitroprusside
• Causes nitric oxide release
• Short acting
• Cyanide metabolite
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Tachycardia; number, common causes, tretment
• HR > 200 beats/min
Most Common Cause
• Pain
• Myocardial irritation
• Spleen dz?
Treatments
• Analgesic drugs
• Lidocaine
• procainamide
111
Basic Monitoring of Respiratory System
Mucous membrane color
• Hypoxia
Respiratory rate
• Chest expansion
• Rebreathing bag motion
• Condensation in the ET tube
112
Normal Breaths per Min in Dogs, Cats Horses
Dogs
• 10-35 BPM
Cats
• 20-30 BPM
Horses
• 8-12 BPM
113
Pulse Oximeter Basics & Interference
o Arterial hemoglobin = O2 saturation
o Normal = > 90%
Interference
• From motion and fluorescent light sources
• Pigmented mucous membrane
• Alpha-2 agonists (high doses) induced peripheral vasoconstriction
• Hypotension
• Hypothermia
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Causes of Hypoxia & Treatment
• SpO2 < 90% or < 60mmHg
Decreased FIO2
• Increase O2
Hypoventilation
• Assist ventilation
Impaired diffusion
• Treat disease w/ drugs
Ventilation/Perfusion mismatch
• Increase ventilation to match or maneuver patient to open up alveoli
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Cardiac shunting (R-L)
• Correct shunt
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115
Co-oximeter
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Monitors –
• O2 carrying hemoglobin
• Non-O2 carrying but normal hemoglobin
• Carboxyhemoglobin
• Methemoglobin
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Normal Tidal Vol & minute ventilation
o Should be 10-20 ml/kg
| o Resp rate X tidal V = minute ventilation = 100-200 ml/kg/min
117
Capnography; basics, hypo/hypercapnia
o EtCO2 = end-tidal carbon dioxide.
o Normal expired CO2 tension is 35-45 mmHg
Hypocapnia
• ETCO2 < 35mmHg
• Hyperventilation
• Pain/distress
Hypercapnia
• ETCO2 > 45mmHg
• Common w/ anesthesia
• Hypoventilation
118
Arterial Blood Gas Analysis; Method & What does it Assess?
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Method
• Anaerobic technique
• Heparinized syringes
• Collected slowly over the course of several breaths
• Analyze samples immediately
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Assesses
• Acid-base status
• Adequacy of ventilation
• Ability of lungs to oxygenate blood
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Arterial Blood Gas Analysis; What does it measure
* pH (7.4)
* PCO2 (40 mmHg)
* PO2 (80 – 100 mmHg)
* SO2 (> 90%)
• BE (-4 to +4)
* HCO3- (24 mmol/L)
