Term
| Three methods of storing and delivering oxygen to an anesthesia machine |
|
Definition
| liquid oxygen, compressed gas, oxygen generator |
|
|
Term
| what is the pressure of a full oxygen cylinder? |
|
Definition
|
|
Term
| what is the pressure reduced by before oxygen enters the flow meter? |
|
Definition
|
|
Term
| How do you determine how many liters of oxygen are left in an e-cylinder? |
|
Definition
|
|
Term
| when should you change an oxygen cylinder? |
|
Definition
|
|
Term
| What is the purpose of the "pin-index" system? |
|
Definition
| Prevents attachment of incorrect gas cylinder |
|
|
Term
| What is the purpose of the flow meter? |
|
Definition
| Measures gas flow in mls or liters per minute going to the vaporizer |
|
|
Term
| What is the oxygen flush valve? |
|
Definition
| Allows oxygen to bypass the flow meters and vaporizer, delivering pure oxygen to the patient. Flow rate is 35-75 L/min |
|
|
Term
|
Definition
| oxygen + vaporized anesthetic |
|
|
Term
| Where is the fresh gas line attached to the breathing circuit? |
|
Definition
|
|
Term
| What is the difference between rebreathing and non-rebreathing circuits? |
|
Definition
| In a rebreathing circuit, all exhaled gases except CO2 are recirculated and rebreathed by the animal. In a non-rebreathing system, none of the exhaled gases are rebreathed by the patient; all exhaled gases are sent to a scavenger. |
|
|
Term
| What is the purpose of the unidirectional valves in a circle system? |
|
Definition
| Keep the gas flowing in one direction and prevents the animal from rebreathing carbon dioxide |
|
|
Term
| What happens to exhaled carbon dioxide in a circle system? |
|
Definition
| Removed by the CO2 absorber or evacuated by the scavenge. |
|
|
Term
| How do you know what size reservoir bag to use in a circle system? |
|
Definition
| 30ml/lb or 6 times tidal volume |
|
|
Term
| What is the purpose of the reservoir bag? |
|
Definition
| Acts as a reservoir, monitor breathing, bagging |
|
|
Term
| What is the difference between a semi-closed and a closed circle system? |
|
Definition
closed = all exhaled gases rebreathed, oxygen flow rate equal to metabolic requirements, pop off valve closed or open.
semi-closed = oxygen flow rate greater than metabolic requirements, some exhaled gas exits through partially open pop-off valve |
|
|
Term
| Adult size breathing circuits are for patients over ___ lbs. The pediatric size breathing circuit is for patients between ___ and ____ lbs. |
|
Definition
|
|
Term
| What does dead space refer to? |
|
Definition
| begins at y-piece, may include face mask or endotracheal tube extending beyond the nose |
|
|
Term
| Purpose of the pressure manometer |
|
Definition
| Measures pressure within a breathing system. Used to determine how big of a tidal volume to deliver to a patient. |
|
|
Term
How big does the CO2 absorber need to be?
What are the granules made of? |
|
Definition
| 2 x tidal volume, soda lime or bara lime |
|
|
Term
| Why does channeling occur? |
|
Definition
| uneven distribution/clumping of granules, allowing gases to bypass them. This can be caused by uneven packing or exposure to heat and water (byproducts of Co2 absorption) |
|
|
Term
| What is the pop-off valve? |
|
Definition
| Allows exit of waste gases to the scavenger, prevents buildup of pressure within the system |
|
|
Term
| What is the purpose of a universal F circuit? What is the minimum weight requirement to use these and why? |
|
Definition
Aids in warming and humidification of inspired gases.
Increased inspiratory resistance, patients must be >20 lb |
|
|
Term
| Is a universal F circuit more like a bain circuit or a circle system? |
|
Definition
| Identical to a circle system. It is an alternate configuration of the y-piece in which the inspiratory tube runs on the inside of the expiratory tube. |
|
|
Term
| What are the advantages and disadvantages of a closed circle system? |
|
Definition
Advantages = more economical, less pollution, conserves heat and humidity, do not have to close and open popoff valve
Disadvantages = Risk of hypoxia, takes longer to change anesthetic concentration |
|
|
Term
| What is meant by "low flow" anesthesia |
|
Definition
| semi closed system, when oxygen flow rate is close to the metabolic requirement but just barely exceeds it |
|
|
Term
| What are the advantages of a low flow system? |
|
Definition
| more economical, inspired gases are warmed and humidified, atmospheric pollution is reduced |
|
|
Term
| Potential disadvantages to a low flow system |
|
Definition
| hypoxia, changes to the anesthetic system are very slow, cannot be used on very small patients |
|
|
Term
| How do you test a circle system for leaks? |
|
Definition
| Close popoff valve, occlude the y-piece with your thumb, depress the oxygen flush valve until the manometer reads 20, observe manometer for decrease in pressure |
|
|
Term
| In a bain circuit, the patient inspires fresh gas from the _____. The patient exhales into the ______. What happens during the expiratory pause? |
|
Definition
outer reservoir tube (although it came from the inner tube originally)
outer reservoir tube.
Fresh gas from the inner tube flushes out expired gas from the reservoir tube |
|
|
Term
| What is the lowest oxygen flow rate that can be used in a bain circuit? |
|
Definition
|
|
Term
| Does any rebreathing occur at this flow rate? |
|
Definition
| yes - to eliminate all rebreathing, you would need a flow rate of 3 times minute ventilation |
|
|
Term
| what is minute ventilation equal to? |
|
Definition
| RR (respiratory rate) x TV (tidal volume) |
|
|
Term
| Why is a bain ciruit used with patients less than 5-6 lbs? |
|
Definition
| decreased dead space and resistance to breathing |
|
|
Term
| Advantages and disadvantages of a bain circuit |
|
Definition
advantages: compact, inexpensive, low dead space and resistance to breathing, facilitates scavenging of waste gases
disadvantages: uses more oxygen and anesthetic gas per lb, loss of heat and humidity, cannot use oxygen flush valve (barotrauma) |
|
|
Term
| How do you test for leaks in the inner tube of a bain circuit? |
|
Definition
| In systems fitted with a bag, push the oxygen flush valve. If tube is intact, the bag will be flat. If there are leaks, the bag will fill. |
|
|
Term
| What is the oxygen flow rate for a closed system? |
|
Definition
| 2-3ml/lb/min (metabolic requirements) |
|
|
Term
|
Definition
| addition to a circle system or bain ciruit, safety device used to prevent pressure build-up in a breathing circuit |
|
|
Term
| Difference between active and passive scavengers? |
|
Definition
active = gas suctioned into scavenger via fan or vacuum
Passive = positive pressure pushes gas into scavenger |
|
|
Term
| What are three options for deposited scavenged gases? |
|
Definition
1) Through a hole in the wall to the outside
2) f/air canister (activated charcoal)
3) Surgi-vet pure guard (activated charcoal) |
|
|
Term
| Why does the flow rate for a bain circuit have to be so high? |
|
Definition
| Necessary to wash out the majority of exhaled gases during the expiratory pause |
|
|
Term
| Why can't the o2 flush button be pushed when using a bain circuit? |
|
Definition
| may cause barotrauma because a high flow rate will rapidly cause a buildup of pressure due to the small volume of a bain circuit |
|
|
Term
| How is nitrous oxide stored in a compressed gas cylinder? |
|
Definition
|
|
Term
| How do you know how much nitrous oxide is in a compressed gas cylinder? |
|
Definition
| Weigh the tank before using and compare it to the full and empty weights stamped on the outside of the canister. |
|
|
Term
| What is the time constant and how is it calculated? |
|
Definition
| The time constant is used to give the anesthetist a rough idea of how long it will take for a change in anesthetic concentration to occur when using a circle system. It is calculated by dividing the total volume of the breathing circuit by the oxygen flow rate. |
|
|
Term
| How long after a vaporizer dial setting is changed does circuit concentration change? |
|
Definition
|
|
Term
| if a circuit has a volume of 5 L, and the fresh gas flow rate is 2L/min, what is the time constant? How long would it take for a circuit concentration to match the vaporizer dial setting? |
|
Definition
5/2 = 2.5 minutes
2.5 * 5 = 12.5 minutes |
|
|
Term
|
Definition
| anesthetic agents, emergency drugs, fluids, blood, plasma, parenteral nutrition, repeated IV meds, monitor central venous pressure and mean arterial pressure |
|
|
Term
| Why use a catheter instead of a needle? |
|
Definition
Repeated use causes vessel damage, hematomas, etc.
Easily dislodged, perivascular injection more likely, difficult to secure in place |
|
|
Term
| Most common catheter for IV anesthesia/short term use |
|
Definition
|
|
Term
| Type of catheter used long term or as a central line |
|
Definition
|
|
Term
| What are wire guided catheters used for? |
|
Definition
| long term, central venous or arterial line |
|
|
Term
| material used for short term, inexpensive catheters |
|
Definition
|
|
Term
| flexible but expensive material used for long term |
|
Definition
|
|
Term
Name the catheter sites for the following species
dog |
|
Definition
| cephalic, jugular, lateral saphenous |
|
|
Term
|
Definition
| cephalic, jugular, medial saphenous |
|
|
Term
|
Definition
| jugular, cephalic, lateral thoracic |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| considerations for choosing a site |
|
Definition
| must not interfere with surgery, should be accessible during surgery, check patency (inspect and palpate) |
|
|
Term
| in what direction are catheters always placed? |
|
Definition
| with blood flow - towards heart |
|
|
Term
| Materials used to secure a catheter |
|
Definition
| tape, suture, glue, staples, +/- bandage and/or antibiotic ointment |
|
|
Term
|
Definition
| flush with heparinized saline every 4-6 hours, inspect every 24 hours |
|
|
Term
| main purpose of endotracheal intubation |
|
Definition
| insert tube into the trachea to provide a patent airway |
|
|
Term
| Advantages of an endotracheal tube |
|
Definition
Administration of oxygen and inhaled anesthetic agents
Assist or control ventilation
Protect airway
Tracheal suctioning & sampling |
|
|
Term
|
Definition
| orotracheal, nasotracheal, via pharyngotomy or tracheotomy |
|
|
Term
| what does the endotracheal tube size indicate? |
|
Definition
|
|
Term
| what happens to resistance to breathing as the size gets bigger? |
|
Definition
|
|
Term
| How far down the trachea should the tube be placed? What happens if it is too short or too long? |
|
Definition
| Cuff should be in middle third of trachea. If it is too short, it is too easily dislodged. If too long, may intubate a main-stem bronchus, increases dead space |
|
|
Term
| What is the purpose of murphy's eye? |
|
Definition
| safety device in case end of the tube gets blocked |
|
|
Term
| Which is better, high-volume or low-volume cuffs and why? |
|
Definition
| high volume cuffs will exert less pressure per square inch and there is less risk of trauma |
|
|
Term
| When are cole tubes used? |
|
Definition
| Used in birds and very small patients, due to larger diameter that will fit without a cuff |
|
|
Term
| considerations for use of a stylet |
|
Definition
| may help in small ruminants, swine, and rabbits. may cause trauma if not careful |
|
|
Term
| species in which laryngospasm is common - what drug can be used to suppress this in cats? |
|
Definition
humans, cats, pigs
lidocaine |
|
|
Term
| What are the negative consequences of esophageal intubation? |
|
Definition
| gastric distention, risk of aspiration, No delivery of oxygen or gas to lungs |
|
|
Term
| What kinds of things can cause an occluded tube? |
|
Definition
| Mucus, saliva, blood, foreign material, "herniated" cuff, tip lodged against wall of trachea, kinking if head is tipped forward |
|
|
Term
| What kinds of things can cause tracheal damage? |
|
Definition
| over-inflation of the cuff (never use cuffed tubes with birds,) harsh chemicals used to disinfect the tubes |
|
|
Term
| species in which you can perform orotracheal intubation with direct vision |
|
Definition
| dogs, cats, birds, pigs, small ruminants |
|
|
Term
| species you must do blind |
|
Definition
|
|
Term
| species you can do blind with palpation |
|
Definition
|
|
Term
| how do you know how much to inflate the cuff? |
|
Definition
| inflate so a leak begins at 15-20 cm water to offer some protection against barotrauma |
|
|
Term
| list four ways that you can be 100% sure the tube is in the trachea |
|
Definition
| look with laryngoscope, palpate for two tubes, auscultate thorax when giving a breath, capnography (gold standard) |
|
|
Term
| list other things that can help confirm placement |
|
Definition
| movement of reservoir bag, condensation in the tube, patient may cough |
|
|
Term
| suspect esophageal intubation if.. |
|
Definition
| regurgitation soon after, patient wakes up after several minutes, cannot get cuff to seal, patient can vocalize |
|
|
Term
| Why should we monitor anesthetized patients? |
|
Definition
| identify problems early, institute treatment promptly, keep patient safe |
|
|
Term
| overall goal of monitoring |
|
Definition
| ensure tissue perfusion with oxygenated blood |
|
|
Term
|
Definition
| anesthetist using touch, sound, and vision to assess patient's vital signs |
|
|
Term
|
Definition
| involves the use of monitors to assess a patient's vital signs. |
|
|
Term
| Three main areas of monitoring |
|
Definition
| circulation, oxygenation, ventilation |
|
|
Term
| what is electrical mechanical dissociation? |
|
Definition
| electrical activity without mechanical activity |
|
|
Term
| What three types of pressures indicate mechanical activity? |
|
Definition
| pulse pressure, mean arterial pressure, central venous pressure |
|
|
Term
| 3 different ways to connect ECG leads to a patient |
|
Definition
| alligator clips, fine gauge wire needles, stick-on patches |
|
|
Term
| What is pulse pressure? Is it a good indicator of mean arterial pressure? |
|
Definition
| pressure produced by movement of blood through the whole arterial system. equal to systolic pressure - diastolic pressure |
|
|
Term
| 2 methods of auditory pulse monitoring |
|
Definition
| esophageal stethoscope, Doppler |
|
|
Term
| How does the doppler work? |
|
Definition
| An ultrasonic probe that emits ultrasound frequency waves is placed over a peripheral artery. Another crystal receives the returning echoes, which are sent to the electronic monitor, which converts it to a whooshing sound. Systolic pressure is when you can hear the blood when the cuff is slowly released |
|
|
Term
| How can false readings be made by the doppler? |
|
Definition
| patient positioning, blood flow altered by ties, motion, proficiency of using machine |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| define mean arterial pressure. what pressure needs to be maintained during anesthesia? |
|
Definition
| Lateral force per unit area exerted on a vessel wall. It is what drives blood. greater than 60 mm Hg needs to be maintained |
|
|
Term
| How do you calculate MAP? |
|
Definition
| (systolic + diastolic + diastolic)/3 = MAP in mm Hg |
|
|
Term
| Name two indirect methods of getting arterial blood pressure. |
|
Definition
|
|
Term
| How does the Dinamap (oscillometric method) work? |
|
Definition
| Detects pressure pulsations produced within a cuff bladder - microprocessor inflates device to suprasystolic pressure and then deflates. can measure Systolic, diastolic, and mean pressures |
|
|
Term
| How do you determine the cuff width? What happens if the cuff is too small or too large? |
|
Definition
| 40% of limb circumference. If it is too narrow, values are artificially elevated. If too wide, values are artificially low |
|
|
Term
best location for cuff placement on a
cat
dog
horse
ruminant |
|
Definition
above elbow on medial side
distal forelimb or rear limb
tail
tail or distal limb |
|
|
Term
| Name two direct arterial blood pressure methods |
|
Definition
1) Mechanical movement converted to electrical energy via a transducer and red with an oscilloscope
2) Pulsations red with an aneroid manometer |
|
|
Term
| Where exactly is CVP measured and what does it tell us about the heart? |
|
Definition
| intrathoracic vena cava or right atrium. It reflects the ability of the heart ot pump blood returning to it, and adequacy of circulating blood volume. |
|
|
Term
| 2 observation methods of ventilation monitoring |
|
Definition
| thoracic wall movement or breathing bag movement |
|
|
Term
| two auditory methods of monitoring ventilation |
|
Definition
| "honker" or esophageal stethescope |
|
|
Term
| two methods of measuring carbon dioxide (as indicator of ventilation) |
|
Definition
|
|
Term
| 4 things to assess when visually observing ventilation |
|
Definition
rate, rhythm, nature, effort
*look for sudden changes in rate |
|
|
Term
|
Definition
| too light or too deep, drug induced, obese, geriatric, hypoxia |
|
|
Term
| reasons for bradypnea or apnea |
|
Definition
| CNS depression, opioids, barbituates, propofol, after neuro procedures |
|
|
Term
|
Definition
| measures changes in air temp |
|
|
Term
| Capnograph is an instrument that measures ______ to provide an estimate of _____ |
|
Definition
| end tidal CO2, arterial partial pressure of carbon dioxide |
|
|
Term
| what is the normal partial pressure of arterial co2? |
|
Definition
|
|
Term
| in regards to ventilation, increased CO2 indicates... |
|
Definition
| hypoventilation, overproduction, rebreathing |
|
|
Term
| in regards to ventilation, decreased CO2 indicates... |
|
Definition
| hyperventilation, cardiac arrest |
|
|
Term
| what is cardiogenic oscillation? |
|
Definition
| undulations in capnogram that are synchronous with cardiac contractions |
|
|
Term
| Reasons for rebreathing of carbon dioxide |
|
Definition
| dead space, faulty unidirectional valves, used up CO2 absorber |
|
|
Term
| Difference between a mainstream and a sidestream capnograph |
|
Definition
Mainstream = sensor placed directly btwn ET tube and breathing circuit.
Sidestream = sensor chamber located in computerized monitor and air is pulled through a tube attached between the ET tube and breathing circuit. |
|
|
Term
| advantages/disadvantages of a sidestream |
|
Definition
| adds little dead space, but there is a 2-3 second delay |
|
|
Term
| 3 methods of monitoring oxygenation |
|
Definition
| mucous membrane color, arterial blood gas analysis, pulse oximetry |
|
|
Term
| 3 things that adequate oxygenation depends upon |
|
Definition
adequate blood oxygen (bound and dissolved)
adequate hemoglobin content
adequate peripheral perfusion |
|
|
Term
| at what point on the oxyhemoglobin dissociation curve do you become hypoxic? |
|
Definition
90% saturation of hemoglobin
PO2 of 60 mm Hg |
|
|
Term
| At what level of unsaturated hemoglobin does cyanosis occur? Why is this an unreliable indicator? |
|
Definition
5 g unsaturated hemoglobin/100 ml
anemia, bad lighting, skin pigment |
|
|
Term
| How do you determine mathematically how much oxygen is bound to hemoglobin? |
|
Definition
PCV/3 = Hgb/dl
(%saturation) x (hgb/dl) = g saturated hemoglobin |
|
|
Term
| Does the pulse ox determine P02 or saturation? Is this always a good indicator of perfusion? |
|
Definition
Saturation
No, dissolved oxygen must be assessed |
|
|
Term
| Information provided by arterial blood gas analysis |
|
Definition
| acid-base status, hemoglobin saturation, PO2, partial pressure of carbon dioxide |
|
|
Term
| information provided by pulse ox |
|
Definition
continuous reading of %saturation of hemoglobin.
pulse rate, rhythm, cardiac output |
|
|
Term
| How does the pulse ox work? |
|
Definition
| Hgb and Oxyhgb absorb at different wavelengths. Light passes through a tissue bed, and a sensor reads the absorption of light. HR is determined by detecting pulsations in the small arterioles |
|
|
Term
| What can cause interference with the pulse ox? |
|
Definition
| motion, poor perfusion, optical interference (external light, anemia, carbon monoxide, methemoglobin, intravascular dies) |
|
|
Term
| How to you monitor depth of anesthesia? |
|
Definition
| CNS activity (EEG), muscle tone, response to stimuli, sympathetic responses (HR, BP, RR,) eye position/movement |
|
|
Term
| surgical plane of anesthesia is indicated by what eye position? |
|
Definition
| cross-eyed and dull palpebral reflex |
|
|
Term
| In horses, what eye activity indicates a light plane of anesthesia? |
|
Definition
|
|
Term
| How to monitor blood loss - subjectively and objectively |
|
Definition
subjectively - inaccurate, can't see it all, 1 gauze can contain 10 mls of blood
objectively - weigh swabs, measure volume in suction canisters |
|
|
Term
| Where is core body temperature taken? What about peripheral? |
|
Definition
esophageal or middle ear
rectal, nasal |
|
|
Term
| Consequences of hypothermia during anesthesia |
|
Definition
| increased cardiac irritability, shivering increases oxygen requirements, decreases recovery time, decreases anesthetic requirements, hypoventilation, increased blood viscosity |
|
|
