Term
| Why is preaneshtetic patient evaluation important? |
|
Definition
-drug selection
-case management |
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Term
| The American Society of Anesthesiologists classify preanesthetic patiens in 6 classes. What are they? |
|
Definition
-Class I: normal, helthy patient
-Class II: mild systemic disease
-Class III: moderate systemic dz
-Class IV: severe systemic disease which is constant threat to life
-Class V: patient is moribund, unlikely to survivie 24 hours
-E = emergency |
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Term
| What ASA classification are colic cases? |
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Definition
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Term
| What ASA classification are GDV cases? |
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Definition
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Term
| We note the signalment of the patient during the preanesthetic evaluation. What is involved with the signalment? Why are each important? |
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Definition
-species: drug handling differs
-Breed: conformation, size, temp diff
-Age: changes in organ/system function
-Gender: usually irrelevant |
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Term
| What are the categories of anemnesis and presenting problem that we evaluate during preanesthetic patient evaluation? Which are most important? |
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Definition
-duration and nature of problem
-concurrent dz processes
-level and nature of physical activity: MOST IMPORTANT!!!
-previous and present drugs
-anesthetic history
-feeding habits and schedule |
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Term
| Why is weight important foro anesthetic purposes? |
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Definition
| -animal must be dosed for the weight they are supposed to be because their CNS has not changed size |
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Term
| Ho do we conduct the PE by system during the preanesthetic patient eval? |
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Definition
-CV: HR, rhythm, auscultation, pulse quality, capillary refill time
-Pulmonary: RR, depth, auscultation, MM, percussion, anatomic considerations
-Hepatic: evidence of jaundice/ascites, clotting failure, palpate liver |
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Term
| Which parts of the PE are most imporrtant during the preanesthetic patient eval? Why? |
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Definition
***CV and pulmonary most important!!!
-they can affect all other systems
-renal: express bladder, kidneys
-GI: general appearance, vomitus/feces, parasites, distention
-Nervous: mentation status, behavioral changes
-Integument
-MSK |
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Term
| What diagnostics are a part of our preanesthetic patient eval? |
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Definition
-PCV, TP, BUN, Gluc
-CBC, renal/hepatic eval, electrolytes, arterial blood gases, clotting times
-UA
-ECG
-Imaging: rads, US, CT, MR |
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Term
| True or False: All veterinary use anesthesia machines are standardized by the American Society for Testing and Materials. |
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Definition
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Term
| What part of the anesthesia equipment supports the airway? Describe proper placement. |
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Definition
-Endotracheal tubes
-does not extend distal beyond the thoracic inlet, not extend rostrally beyond patient incisors |
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Term
| A properly inflated cuff will do what 4 things? |
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Definition
-patent airway
-facilitate positive pressure ventilation
-protect the lungs from aspiration of fluids
-prevent contamination of the work environment with waste gases |
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Term
| What type of ET is most common? |
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Definition
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Term
| What is the purpose of Murphy's eye? |
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Definition
| -provides an alternative route for gas to flow should occlusion occur |
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Term
| In a Low Volume: High Pressure system, what does the balloon portray? |
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Definition
| -the pressure created by the elastic recoil of the cuff |
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Term
| In a High Volume: low Pressure system, what does the balloon portray? |
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Definition
| -pressure exerted on the tracheal wall |
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Term
| Tracheal wall rpessure > ___ cm H2O can impede cap blood flow however, tracheal wall pressure below ___ mmHg can increase risk of aspiration. |
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Definition
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Term
| What is special about a Cole ET tube? |
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Definition
| -tapered shoulder is used to position the tube in the larynx forming a seal |
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Term
| What is the purpose of a spiral embedded or armored ET? |
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Definition
| -to prevent collapse when bent or folded |
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Term
| What is unique about a self-sealing ET tube? |
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Definition
| -lacks an inflatable cuff and relies on a series of soft flexible flanges to privde airway security |
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Term
| Between a Murphy-type and a Magill-type ET, which is low volume, high pressure? Which is high volume, low pressure? |
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Definition
-Magil type = low V, high P
-Murphy type = high V, low P |
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Term
| What do SGAD and LMA stand for? |
|
Definition
-SGAD = supraglottic airway devices
-LMA = laryngeal mask airways |
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Term
| In which animals do we use SGADs? What makes them special? |
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Definition
-felines and rabbits
-do not require a laryngoscope for placement and do not enter the larynx or trachea, will fomr a tight seal around the glottis |
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Term
| What are the two main types of laryngoscopes? |
|
Definition
-MacIntoch: curved, prominent vertical flange
-Miller: strait, less prominenet vertical flange |
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Term
| Describe Nasotracheal intubation. What drug do we use with it? Dangers? |
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Definition
-nastril, nasal meatus, and larynx through the trachea
-use lidocaine gel and CO2
-can cause nasal hemorrhage and other tissue damage |
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Term
| When do we use wire/tube guided intubation? |
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Definition
| -when we cannot see direct laryngeal visualization |
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Term
| When do we use endoscope guided intubation? |
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Definition
| -species or specific conditions: rabbits and other small mammals OR equine with difficult airway |
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Term
| When do we use endotracheal tube exchangers? |
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Definition
| -when we need to hcange tubes out |
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Term
| When do we use retrograde intubation? How do we do it? |
|
Definition
-South American Camelids and mice
-go between upper tracheal rings
-cuff should be CAUDAL ot the puncture site to avoid forced gases from going SQ or into the mediastinum during PPV |
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Term
| What is the point of supllemental oxygen? |
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Definition
| -used to increase the partial pressure of oxygen in arterial blood and to promote delivery of oxygen to the tissues |
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Term
| What occurences can lead to the necessity of supplemental oxygen? |
|
Definition
-diffusion abnormalities
-V/Q mismatch
-hypoventilation
-NOT for R-L vascular shunts |
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Term
| Which situation calls for insufflation? |
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Definition
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Term
| What are the possible results of oxygen toxicity? |
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Definition
| -deterioration of pulmonary function, leads to endothelial damage, destruction of alveolar cells and increased micoavascular permeability leading to edema, hemorrhage, and congestion, later stages alveolar type II fibroblast proliferation resulting is fibrosis |
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Term
| What are the 4 components common to all anesthesia machines? |
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Definition
-oxygen source
-oxygen regulator
-flowmeter
-vaporizer |
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Term
| On a US anesthesia machine, what does the color green mean? yellow? blue? |
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Definition
-green = oxygen
-yellow = air
-blue = N2O |
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Term
| In an international anesthesia machine, what does the color white mean? Black? Blue? |
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Definition
-white = Oxygen or air
-black = air
-blue = N2O |
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Term
| What are the 4 gas safety mechanisms on anesthesia machines? |
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Definition
-color coding per gas
-diameter index safety system: non-interchangeable gas specific threaded connection system
-quick connectors
-pin-index safety system: gas-specific patterns on hanger yokes |
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Term
| What are the 2 main functions of the pressure reducing valves? Where are they found? |
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Definition
-brings the high pressure of gas cylinders down to a reasonable and safe working pressure
-also prevent flunctuations in pressure as the tank empties
-found wherever high pressure cylinder is located |
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Term
| What is the function of the pressure gauges? |
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Definition
| -measure cylinger pressure, pipeline pressures, anesthetic machine working pressure within the breathing system |
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Term
| Outline a high pressure system. |
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Definition
| -gas cylinder => hanger yoke => yoke block => cylinder pressure => pressure regulator |
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Term
| Outline an intermediate pressure system. |
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Definition
| -receives gases as reduced pressures => conduits rom the pipeline inlets to the flowmeters => oxygen flush valves => pipeline ilet connections => pipeline pressure gauges => ventilator power outlets |
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Term
| Outline a low pressure system. |
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Definition
| -downstream from the flow meter (pressure is slightly above atmospheric pressure) => vaporizers => piping from the flow meters to the vaporizer => common gas outlet => APL valve => breathing systems |
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Term
| What is the purpose of a flowmeter? |
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Definition
-control rate of gas delivery
-determine fresh gas flow |
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Term
| How does the energy required for vaporizaiton relate to energy requirements? |
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Definition
| -the vaporization requires energy which is a loss of heat from the liquid, as vaporization proceeds temp of the liquid decreases and so does the vapor pressure unless heat can readily enter the system |
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Term
| Definition: Liquids boiling point |
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Definition
| -temperature at which its vapor pressure is equal to the ATM as the ATM pressure decreases so does the BP |
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Term
| The higher the temperature, the (greater/lesser) the vapor pressure. |
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Definition
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Term
| How does a vaporizer work? |
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Definition
| -the molecules in a closed container are distributed b/n the liquid and gas phase => the gas bombards the wall of the container creating the saturated vapor pressure of the agent |
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Term
| What does it mean when you say "vaporizer OUT of circuit? What is its advantage? |
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Definition
-it is not in the breathing circuit
-precision |
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Term
| What does it mean when you say vaporizer IN circuit? What is its advantage? |
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Definition
-the vaporizer is in the breathing circuit
-loses precision but has low resistance |
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Term
| Describe the 6 general characteristics of modern vaporizers? |
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Definition
-agent specific
-concentration alibrated
-variable bypass
-flow over wick
-out of circle
-high resistance |
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Term
| What is the function of a temperature compensation vaporizer? |
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Definition
| -supply and conduct heat efficiently promoting thermostability |
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Term
| How does a metal rod temperature compensating vaporizer work? |
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Definition
| -alters the splitting ratio to allow more or less vapor depending on the temperature |
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Term
| How do bi-metallic temperature compensating vaporizers work? |
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Definition
| -the bi-metallic strips expand and contract in response to temperature changes |
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Term
| Flo compensation ensures consistent saturation of all gases flowing through the vaporizing chamber by using ______, ______, and ______ to facilitate liquid gas vaporization, thus to increase of surface area, gas is then fully saturated. |
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Definition
-wicks
-baffles
-spiral tracks |
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Term
| Definition: Pumping effect |
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Definition
| -fluctuations in pressure from positive pressure ventilation or with the use of the flush valve in older machines may cause a transient reversal of flow through the vaporizer changing the output (more pronounced at low flows) |
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Term
| How do we fix back pressure (3)? |
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Definition
-reduce the size of vaporizing chamber relative to the bypass chamber
0use long spiral or small diameter tube connecting the vaporizer chamber to the bypass channel
-one way check valves upstream from the vaporizer or downstream from the vaporizer before the flow meter |
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Term
| What are the 4 major types of vaporizers? |
|
Definition
-Ohmeda Tec
-Drager Vapor
-Penlon Sigma Series
-Electric |
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Term
| Read Slide 28 of Lecutre 2 |
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Definition
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Term
| In regards to vaporizers, what is the result of excessive tipping? |
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Definition
| -can flood the bypass area |
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Term
| True or False: Most vaporizers compensate for changes in ambient pressure. |
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Definition
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Term
| Describe vaporizer maintenance. Why is this important? |
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Definition
-maintain per factory but usually once a year
-halothat and methoxy contained preservatives and would collect on the wicks |
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Term
| What is a possible negative consequence of using the wrong inhalant in the vaporizer? |
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Definition
| -depends on the vapor pressure of the offending inhalant ex: lower output if a lower pressure inhalant is placed |
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Term
| What is the ER use of the common gas outlet? |
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Definition
| -large volumes of non-anesthetic gas to the patient breathing circuit to flush the system free on inhalant |
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Term
| True or False: Breathing systems are considered a part of the anesthesia machine. |
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Definition
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Term
| What are the purposes of breathing systems? |
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Definition
-direct O2 to the patient
-remove CO2 from inhaled breaths
-means for controlling ventilation |
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Term
| What are the three types of rebreathing systems? |
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Definition
-full rebreathing (open)
-partial rebreathing (semi-closed or low flow)
-minimal rebreathing (semi-open) |
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Term
| True or False: Fresh gas flow determines the amount of rebreathing. |
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Definition
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Term
| Describe the flow rate of rebreathing systems. Any advantages? Any disadvantages? |
|
Definition
-lower flow rates
-Advantage: less environmental damage due to less spill of halogenated compounds, marginal maintenance of body temp
-Disadvantage: difficult to control depth of anesthesia and decreased anesthetic gas delivery |
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Term
| What is the difference between a full rebreathing system and partial & minimal rebreathing systems? |
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Definition
-full rebreahting system gives out the metabolic oxygen consumption of the patient
-partial and minima rebreathing systems give out greater than the metabolic O2 consumption |
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|
Term
| What are the 6 components of the rebreathing system? |
|
Definition
-fresh gas inlet
-inspiratory and expiratory one way valves
-breathing tubes
-APL valve
-reservoir bag
-CO2 canister |
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|
Term
| What is the purpose of the fresh gas inlet? Where does its gas come from and where in the circuit does it sit? |
|
Definition
-site of gas delivery to the circle system
-gas comes from the common gas outlet => after the CO2 canister and before the I-valve |
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Term
| Where does the inspiratory one-way valve get its gas from? |
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Definition
| -gas moves from fresh gas inlet AND reservoir bag |
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Term
| Is the inspiratory one-way valve part of the expiratory or inspiratory limb? Is it closed or open during expiration? |
|
Definition
-inspiratory limb
-closed during inspiration |
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|
Term
| What is the purpose of the expiratoyr one-way valve? |
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Definition
| -aids to direct gas into the reservoir bag |
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Term
| Why are breathing circuit tubes corrugated? |
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Definition
| -prevents kinking and allows for minimal expansion or traction |
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Term
| What are the functions of the reservoir bag? |
|
Definition
-compliant reservoir of gas
-changes in volume with inspiration and expiration |
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Term
| What is the volume of the reservoir bag? |
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Definition
| -volume 5-10X patient's tidal volume |
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Term
| What is the full name of the APL valve? |
|
Definition
| -Adjusting pressure-limiting valve |
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Term
| What is the purpose of the APL valve? Any other names for it? |
|
Definition
-allows excess gas to escape with increasing pressure
-aka pop-off valve, overflow valve, pressure relief valve |
|
|
Term
| -Is the pressure relief valve closed or open during ventialtion? What about during positive pressure ventilation? |
|
Definition
|
|
Term
| What is the purpose of the CO2 absorber? |
|
Definition
| -removes CO2 from exhaled gases |
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|
Term
| What is the purpose of the scren? |
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Definition
| -to prevent CO2 absorbent granule from entering the breathing circuit |
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Term
| What is the purpose of a baffling system? |
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Definition
| -prevents channeling of gases within the canister |
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Term
| What is the general reaction that takes place within the CO2 absorbent conaister? |
|
Definition
| BAse + neutralizing acid (CO2) => water + carbonate + heat |
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Term
| Give a couple of examples of CO2 absorbents. |
|
Definition
-Baralyme
-Amsorb
-Soda lime
-Amsorb |
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|
Term
| What does the manometer measure? In what units? |
|
Definition
-pressure within the breathing circuit
-cmH2O |
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|
Term
| What should the manometer read in a small animal? Large animal? |
|
Definition
-SA < 20 cmH2O
-LA < 30 cmH2O |
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Term
| What is the purpose of the air intake valve? |
|
Definition
| -negative pressure relief valve |
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|
Term
| Where is the air intake valve located? |
|
Definition
| -the top of the inspiratory valve |
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|
Term
| What is the significance of a collapsed reservoir bag in a full rebreathing system? |
|
Definition
-the flow rate is too low
-flow must meet requirement for accurate vaporizer use |
|
|
Term
| Which gas can you not use in a full rebreathing system? Why? |
|
Definition
-Nitrous Oxide
-hypozic mixture |
|
|
Term
| What are the benefits of a full rebreathing system? |
|
Definition
| -economical, preserves heat and humidity, decrease waste |
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Term
| What is the major disadvatnage of closed and low flow systems? |
|
Definition
| -requires more time to change concentration of inhalant |
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|
Term
| In what type of ventilators are closed and low flow systems common? |
|
Definition
|
|
Term
| Why are non-rebreathing systems not common? |
|
Definition
| -waste a lot of gas and money |
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|
Term
| What is another name for a non-rebreathing system. |
|
Definition
|
|
Term
| How do Mapleson systems remove CO2? |
|
Definition
| -via high fresh gas flows |
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|
Term
| What are the 3 benefits of non-rebreathing systems? |
|
Definition
-minimal resistance
-less mechanical dead space
-quick changes in inhalant anesthetic concentration |
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|
Term
| What are the disadvantages of non-rebreathing systems? |
|
Definition
-less cost effective: increased use of O2 and inhalant
-loss of heat and humidity
-can be dangerous is tube are pressed or kinked |
|
|
Term
| What are the two major respiratory assist devices? |
|
Definition
-manual resuscitators: IPPV for SA patients
-demand valves |
|
|
Term
| What is the purpose of a demand valve? Does it have slight negative or positive pressure? |
|
Definition
-set to deliver oxygen when the patient inspires
-slight negative pressure starts gas delivery |
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