Anesthesia Flashcards
Anticholinergics
Atropine and glycopyrrolate
Properties that influence the way agents are used
Vapor pressure, blood-gas partition coefficient, minimum alveolar concentration (MAC)
Vapor pressure
Measurement of the tendency of a liquid to evaporate.
Blood-gas Partition coefficient
The measurement of the tendency of an agent to dissolve in blood. Associated with the speed of induction, recovery and change in depth of anesthesia
MAC (minimum alveolar concentration)
The percent concentration of an agent required to prevent a response to surgical stimulation in 50% of patients. Measurement of the potency of an agent.
Halogenated anesthetics
Inhalant agents used to induce and maintain general anesthesia, such as Isoflurane and Sevoflurane.
Vapor pressure of Isoflurane
240 mm Hg
Vapor pressure of sevoflurane
160 mm Hg
Desflurane
Boiling point is near room temperature, therefore requires a special expensive electronic vaporizer. Inductions and recoveries are even more rapid than with Sevoflurane
Endotracheal tube’s
Used to administer oxygen and inhalant anesthetics.
Maintains an open airway.
Facilitates administration of supplemental oxygen.
Allows manual ventilation.
Types of endotracheal tubes
Red rubber, silicon rubber, polyvinylchloride
Murphy tubes
Side hole called the Murphy eye.
Beveled end
Parts of the endotracheal tube
Connector
Cuff
Valve
Pilot balloon
Laryngoscopes
Used to visualize the larynx while placing endotracheal tubes
Supraglottic airway devices (SAD)
Creates a seal around the laryngeal opening without invading the tracheal lumen.
General systems of the anesthesia machine
The carrier gas supply
The anesthetic vaporizer
The breathing circuit
This cabbaging system
Carrier gas supply
Delivers carrier gases to the patient at controlled flow rates
Anesthetic vaporizer
Vaporizers a precise concentration of liquid inhalant anesthetic and mixes it with the carrier gas.
Breathing circuit
Delivers the anesthetic and oxygen mixture via and a tracheal tube, mask, or chamber and Conway is expired gases away.
Rebreathing and non-rebreathing
Scavenging system
Disposes of waste and excess anesthetic gases
Carrier gas used during all and aesthetic procedures
Oxygen
Tidal volume
The volume of a normal breath (~10-15 mL/kg body weight)
Oxygen cylinders
Color coded as green in the United States, or white internationally.
Tank pressure gauge
Indicates the pressure in a compressed gas cylinder
Pressure reducing valve
Reduces the pressure of gas exiting the compressed gas cylinder to 40 - 50 psi
Line pressure gauge
Indicates pressure in the line connecting the pressure-reducing valve to the flowmeter.
Flow meter
Controls the rate at which carrier gas is delivered to the patient and reduces the pressure from 40 to 50 psi to 15 psi
Common standard used for oxygen flow rate for SA
1 to 2 L/min
Oxygen flush valve
Delivers pure oxygen at 35 to 75 L/min directly to the breeding circuit, bypassing the flowmeter and the vaporizer.
Oxygen flow rates for chamber induction for small animals, foals, calves, small ruminants
5 L/min
Oxygen flow rate for mask in ductions for small animals, foals, calves, small ruminants
1 to 3 L/min for 10 kg or less
3 to 5 L/min for more than 10 kg
Precision vaporizers
Oh miles per Syse delivery of higher vapor pressure inhalants, such as iso and Sevo. Located out of the breeding circuit; vaporizer out-of-circuit
Non-Percision vaporizers
Only used with low vapor pressure and aesthetics. Located in the breathing circuit.
Vaporizer inlet port
The point where oxygen and other carrier gases enter the vaporizer from the flowmeter.
Vaporizer outlet port
The point where oxygen, inhalant anesthetic, and other carrier gases exit the vaporizer.
Vaporizer fresh gas in let
The point at which the gases enter the breathing circuit
Non-rebreathing system
Recommended for patients weighing less than 7 kg.
Flush out expired gases with the use of a relatively high oxygen rate.
Don’t require a CO2 absorbent canister or unidirectional valves.
Types of non-rebreathing circuits
Bain coaxial circuit
Ayre’s T-piece
Jackson-Reed circuit
Norman Mask elbow
Disadvantages of non-rebreathing systems
Don’t conserve gases, moisture or body heat.
Manual ventilation and waste gas scavenging are more difficult.
The CO2 absorbent canister
Prevent the patient from rebreathing toxic levels of CO2
Pressure Manometer
Indicates pressure in the breeding circuit and in the patient’s lungs
Active scavenging system
Uses a vacuum pump or fan to remove waste gas
Passive scavenging
Works by gravitational flow
Postinduction apnea
Hypoventilation that follows hyperventilation after inductions.
Malignant hyperthermia
Body temp progressively rises to dangerous levels. Most common in pigs.
Esophageal stethescope
Amplifies the sound of the heartbeat
Doppler ultrasound monitor
Detects the flow of blood through small arteries and converts this motion into an audible signal.
Doppler ultrasound monitor probe
Positioned over the artery, adjusted until an audible signal is detected.
Doppler ultrasound probes positioning in small animals
Ventral surface of a paw proximal to the metacarpal or metatarsal pad.
Ventral surface of the table base.
Dorsomedial surface of the hock.
Medial surface of the thigh.
Doppler ultrasound probe positioning in large animals
Ventral tail is most frequently used.
Oscillometric BP monitor
A device used to measure blood pressure and heart rate.
Pulse oximeter
Detect changes in the oxygen saturation of hemoglobin.
Apnea monitor
Used to warn the anesthetist of apnea
Capnograph
Also known as an end-tidal CO2 monitor, measures the level of CO2 present in inspired and expired air.
Induction of anesthesia
Patient is taken from consciousness to unconsciousness
Mask induction vaporizer setting
3% to 5% for Iso
4% to 6% for Sevo
Chamber induction a vaporizer setting
3% to 5% for Iso
4% to 6% for Sevo
Inhalant anesthetic maintenance
- 5 % to 2.5% for Iso
2. 5% to 4% for Sevo
Sterile lubricant
Place in eyes every 90 minutes
Alarming signs during recovery
Includes excitement, vocalization, hyperventilation and head thrashing.
Rinsing out a horse’s mouth with a dose syringe placed between the cheek and the teeth on each side of the mouth to flush out any feed material
Prevent aspiration of material during intubation and recovery.
Ketamine is drawn up before anesthesia for horses
In case of sudden arousal it is administered to the horse to return it to surgical anesthesia
During maintenance of Anastasia horses are more likely to develop
Hypoxemia, hypoventilation and hypotension
Dobutamine
The drug most often used to support blood pressure
Total intravenous anesthesia (TIVA)
Generally characterized by high her blood pressure, better breathing and more active palpable reflexes then seen with inhalant anesthetics in horses.
Used for procedures lasting less than one hour
All ruminants should be positioned for surgery with the mouth lower than the pharynx.
To allow drainage of saliva and any regurgitation of material from the mouth, preventing build up in the pharynx which could lead to aspiration during recovery.
This species has been observed to breathe rapidly and shallowly, somewhat like a panting dog
Ruminants
