Anesthesia vet tech prep power pages

The two most common breathing systems for small animals are

rebreathing and non-rebreathing systems

Breathing systems rely on

the patient's natural ability to breathe in order to function

rebreathers are

circle systems

rebreathers (circle systems) remove ____________ from exhaled gases by ___________________.

carbon dioxide by routing them through a chemical abosrbent.

After the carbon dioxide is removed,

the expired gases are mixed with fresh incoming gas and oxygen to be inhaled by the patient

by rebreathers (circle systems) reusing the expired gases conserves _________ making them economical.

oxygen and anesthtic

rebreathing systems also retain

heat and moisture, promoting patient warmth during the procedure.

The down side to rebreathing systems is

the machine is bulky and complicated.

High resistance to ventilation makes it difficult for smaller animals with a low tidal volume to

move gases through a rebreathing system

non rebreathers

bain systems

non-rebreathers do not

reuse expired gases

non-rebreathers rely on a

high gas flow to flush carbon dioxide into the scavenger system.

non rebreathing systems are appropriate for

small patients with a low tidal volume due to its low resistance to ventilation

the disadvantage to non rebreathers is that

the higher gas flow promotes hypothermia

non rebreathers are expensive to use due to the

high consumption of gases

important checks of anesthetic machines pre procedure

-make sure CO2 absorbent is in date

-vaporizer has plenty of gas

-scavenger system is hooked up

a common problem in anesthetic procedures is a

leak in the system

leaks in anesthetic machines can be found by

a pressure test of the system

leaks in anesthetic machines frequently occur where

the circle tube and reservoir bags are attached.

breathing tubes and bags frequently have to be replaced due to

stress cracks and holes at the connection points

what is the top indication of a anesthetic leak

the smell of anesthetic gas during a procedure

if the vaporizer calibration is off the patient may

become deeply anesthetized or will have a hard time staying anesthetized

One-way valves can become stuck closed, due to

condensation from the patient's expiratory breath. This could cause the patient to breathe unfiltered expired gases

a pressure test indicates if

there are any leaks and if the pop off valve is working properly

pressure test steps

Closing the pop-off valve and occluding the patient end of the breathing circuit.

● The system is then pressurized to 30 cm H2O and the flow meter set at 200 ml/min. The machine is considered leak-free if the pressure on the manometer holds or slowly increases, but if it drops, you have a leak greater than 200 ml/min and it should be found.

to find a leak

listel or feel for it

Leaks can also be found with a surfactant solution. The solution is sprayed on the machine anywhere a leak is suspected and will bubble if one is present

Once the machine is leak free, the pop-off should be

opened to let the pressurized air out of the system. This ensures that the pop-off isn't stuck closed and is working correctly

what are the two times during an anesthetic episode where a patient's state of consciousness is altered

during induction and recovery

During induction, a patient is transferred from a state of

consciousness to unconsciousness

during recovery a patient is transferred from a state of

unconsciousness to consciousness

routes of induction

injectables

inhalants

the preferred method of induction is

injectables it is less stressful due to the fast acting nature of the drugs

you can give injectable induction meds via

intravenous or intramuscular

can you use more than one drug for induction

yes

the downside to injectable agents is that once they are given,

they cannot be controlled and are not immediately eliminated.

Patients induced with inhalants experience a

a prolonged stage two of anesthesia, also known as the "excitement phase."

During stage two of anesthesia, the animal can become

anxious, especially if no premedication is used.

gas induction is a good idea for

animals who are too aggressive to touch or who are very small

inhaled agents can be given 2 ways:

-holding a mask to the animals face

-placing patient in a chamber where they are immersed with the anesthetic

when using an induction chamber to anesthitize, make sure the

chamber is big enough for the patient to lay down with an extended neck

steps to using an induction chamber:

. High oxygen flow rates of 3-5 liters per minute and high gas concentrations of 3-4% for isoflurane and 4-5% for sevoflurane are used to speed up induction. Once the animal appears anesthetized, remove the animal from the chamber and attempt endotracheal intubation. If the patient is not adequately anesthetized to allow for intubation, a mask can be used to administer more anesthetic gas to deepen the anesthetic plane

Mask induction exposes the anesthetist to

less anesthetic than using an induction chamber

steps to using mask induction

, start the vaporizer setting at 0.5% and increase in 0.5% increments every 30 seconds until the patient is sedate, to reduce the animal's stress. Be sure to use the appropriate size mask and diaphragm to reduce the amount of dead space and gas leakage.

berfore deciding anesthetic protocol

take into consideration the animals medical history. . Disposition, concurrent health problems, health status, and reason for anesthesia will aid in deciding the safest and most appropriate anesthetic induction protocol for the patient

Pre-medicating the patient prior to induction will also lessen

the amount of induction drugs needed to sedate the patient.

common injectable induction agents

-propofol

-etomidate

-benzodiazepines: diazepam, midazolam, and zolazepam

-cyclohexamines: ketamine and tiltamine

-barbituates:thiopental and methohexital.

propofol is quickly eliminated from the body by

hepatic and extrahepatic metabolism

what does propofol do to respirations

potentially depresses respirations. May cause apnea after induction

propofol can cause hypotension due to

vasodilation

propofol is

rapid acting

propofol route

IV

does propofol cross the placental barrier

yes but with minimal depressant effects on the fetus

etomidate is

rapid acting

why can inductions on etomidate be rough

because it produces a hypnotic-like state that doesn't completely sedate the patient.

etomadine is eliminated by

hepatic metabolism

why can administration of etomidate be painful

the propylene glycol carrier

etomadine doesnt affect the

cardiovascular system

does etomidate cross the placental barrier

yes but has minimal depressant effects on the fetus

etomidate routes

IV

most common benzodiazepines used for induction

diazapam

midazolam

zolazepam

Benzodiazepines

reduce anxiety and provide skeletal muscle relaxation

Benzodiazepines are always given with another induction agent because

e they do not provide sedation and may cause excitement ex) often given with ketamine

diazepam is not

water soluble

diazepam can only be mixed in a syringe with

ketamine because it is not water soluble

diazepam contains __________ which can be

propylene glycol, which can be irritating to tissues and causes the drug to have an unreliable absorption rate when given intramuscularly.

what is the benzodiazepine part in the combination drug telazol

zolazepam

Benzodiazepines routes

IV and IM

The two most common cyclohexamines used for induction are

ketamine and tiletamine

what do cyclohexamines do to the central nervous system

stimulate unlike most induction agents who suppress it

cyclohexamines produce

muscle rigidity and sensitivity to light, sound, and touch. These effects can be reduced by using other drugs in combination with cyclohexamines.

cyclohexamines increase

heart rate, blood pressure, intraoccular pressure

cyclohexamines are not reccomended for patients with

ocular disease

recovery on cyclohexamines can be rough because

patients tend to become dysphoric

in the dog ketamine is metabolized by

the liver

in the cat ketamine is metabolized in the

kidneys

tiletamine is metabolized

via the kidneys in cats and dogs

what is the cylcohexamine part of the combination drug telazol

tiletamine

cyclohexamines route

IV or IM

The two most common barbiturates used for induction are

thiopental and methohexital

barbiturates have a

rapid onset of action

barbituates cause

respiratory and cardiovascular depression

barbiturates are metabolized

hepatically and extra hepatically

barbiturates distributes to ________ so use caution in

lipid areas of the body so use caution in lean animals. Less body fat will produce more pronounced CNS depression

barbiturates are contradicted in patients with

hypoproteinemia, acidosis, or hypothermia.

thiopental has a

cumulative effect with repeated doses

methohexital does not

have a cumulative effect and does not redistribute into highly lipid tissues as heavily as thiopental does

After induction, the animal is

intubated with an endotracheal tube (even if maintenance with a gas anesthetic is not in the plan

An endotracheal tube will prevent

the aspiration of foreign material into the lungs

an endotracheal tube provides an

effective way to deliver oxygen to the patient and allow for intratracheal drugs

Before intubating, the patient should be

pre-oxygenated with 100% oxygen and the endotracheal tube's inflatable cuff should be checked for leaks

before intubating measure the endotracheal cuff by

placing the tube against the animals throat with the cuffed end just caudal to the thoracic inlet, to ensure adequate length.

to intubate once the animal is positioned by the assistant,

Place the laryngoscope blade on the tongue, just before the epiglottis, and apply downward pressure to expose the tracheal opening. Slide the endotracheal tube past the arytenoids into the trachea.

once the endotracheal tube is placed,

Attach the breathing circuit and turn on the gas.

the last stage of the anesthetic epsidode is

recovery

during recovery, anesthetic agents are discontinued and the patient

returns to a conscious state

when ready to recover, stop anesthetic gas and "flush it out" by

oxygen rate is increased to four liters for ten minutes to "wash out" inhalant anesthetic from the machine and patient.

the best position for recovery is _________ because

sternal recumbency with the animal's head propped up in a natural position to maintain a proper airway and reverse any positional atelectasis.

However, this isn't always possible due to the location of the surgical site or type of surgery. If sternal recovery isn't possible, the patient should be placed in a comfortable position without putting any pressure on surgical incisions

leave the IV catheters in place until

a couple hours after the procedure incase complications arise

the recovery period should be

in a pre warmed cage wit bedding and the patient should not be left alone

hypothermia increases during

recovery time