A loss of sensation; especially to pain
What are the 3 basic types of anesthesia?
Local, regional, and general
Which basic type of anesthesia is the only one that renders the patient unconscious?
Define local anesthesia
A loss of sensation confined to a small/limited part of the body
What are the two types of local anesthesia?
Topical and injectable
Which type of local anesthesia is most commonly used?
Where are topical local anesthetics applied?
Mucous membrane areas of the body
Route of administration for injectable local anesthetics and how they work
*Parenteral (SQ) By blocking the transmission of nerve impulses to that area
Name a few surgical procedures we commonly use local anesthetics for
Skin biopsies Laceration repairs Small tumor removals
6 advantages of local anesthetics
Decrease in patient toxicity, Minimal patient recovery time, Cheaper, Provides analgesia, Ideal for high risk patients, Less equipment
3 Disadvantages for the use of local anesthetics
Patient restraint, concise placement of drug, no control of drug once injected
Typically, all drugs ending in "-caine" are what kind of drug?
Which of the "-caines" are the oldest and still most commonly used in practice today?
Which local anesthetic is in the triple antibiotic ointment that we use on post-op incisions?
Why would epinephrine EVER be added to a local anesthetic?
To provide longer duration of action of a local anesthetic.
Define regional anesthesia
A loss of sensation affecting an area or region of the body
Where are regional anesthetics typically injected?
Around a group of nerves
What is the most common example of regional anesthesia?
Where is an epidural administered?
SQ: between L7 and Sacrum
Why do we use epidurals?
Provides analgesia for up to 24 hours
What is the form of anesthesia called that is injected along the spinal cord on either the left or right side of the spine that causes only 1/2 of the abdomen to be anesthetized?
Paralumbar nerve block
What procedure and animal do we commonly use paralumbar nerve blocks for?
C-sections in cattle
Define general anesthesia
A loss of sensation and consciousness of the patient
What 4 things does general anesthesia ideally include?
Hypnosis/unconsciousness, Hyporeflexia, Analgesia, Muscle relaxation
What is the family of drugs that typically causes muscle rigidity?
What are the two ways in which we can achieve general anesthesia?
via injectables or inhalants
Injectable general anesthesia (ex: CRI) is done by what route of administration and typically for what kind of patients?
IV/IM for fractious patients
What are general anesthetic inhalants?
How are GA inhalants delivered to the patient?
Via mask, ET tube, or chamber
What are GA inhalants typically used in conjunction with?
What are the 4 components of general anesthesia?
PA Induction Maintenance & Recovery
Define PA period
The period of time immediately preceding induction in which you prepare yourself and your patient for the anesthetic procedure.
What is the induction period?
Process by which the patient leaves the normal state of consciousness and enters an unconscious state
How long should the induction period typically be and how is it achieved?
Less than 1 min. achieved by the use of injectable/inhalant drugs
Define maintenance period
Period following induction in which a stable level of anesthesia is achieved
Define recovery period
Period of time following the discontinuance of anesthetics and when the patient's vital signs are WNL.
What is surgical anesthesia?
General anesthesia at a level that allows a surgical procedure to be performed without the patient moving or consciously perceiving pain.
What is balanced anesthesia?
Anesthesia that uses a combination of drugs to achieve the desired effects
What is dissociative anesthesia?
Produced by cyclohexamine anesthetics that interupt the pathways of the brain.
What are the 3 effects of dissociative anesthesia?
Allows brain to dissociate bodily pain, Produces loss of sensation (but not GA), Produces cataleptic state
What is catalepsy?
What 2 drugs, mentioned in class, cause catalepsy?
Ketamine and Tiletamine
What is analgesia?
Absence of stimulus that would normally produce pain
Wind up effect
Pain receptors called Nociceptors, once stimulated, can stimulate other pain receptors in the body. Once pain starts, non-painful stimuli can be perceived anywhere in the body (other than where it originated) as actual pain.
What are the 3 most commonly used analgesic drugs? Of these 3, which one is the best?
Opioids (best), NSAIDs, and local anethetics
What are the 2 main advantages of providing analgesia?
Patient comfort and provides more effective healing at incision site
What are the 3 disadvantages (myths) of analgesics?
Cost to the client, controlled substance issues, and patient reinjuring themselves
What is the TRUE disadvantage of analgesics?
Adverse systemic effects: respiratory depression and hepatotoxicity
What is the universal color for O2 tank?
Universal color for NO2 tank?
How much psi can an E tank hold? An H tank?
Both can hold ~2000-2200 psi
How many liters of O2 can an E tank hold? An H tank?
E tank= 600-660L O2, H tank= ~7000L O2
How are O2 tanks sized?
By alphabet (A is the smallest)
What is the formula for finding out how many liters are left in a E tank?
psi x 0.3 = liters of O2/Patient's O2 flow rate in L = min (round to whole min) or hours (round to 10ths)
When is it recommended to change out an O2 tank?
When O2 pressure gauge reaches >500 psi
What is the function of the O2 pressure regulator?
To reduce the pressure from the compressed gas cylinders to a working constant pressure of about 45-50 psi
What is the function of the flow meter?
To reduce the pressure in the system to 12-15 psi and to deliver calculated O2 to the patient
What are the 2 different styles of flow meters?
Ball or column
How many kgs should a patient be for use of a rebreathing system? Non-rebreathing sytem?
Rebreather= >7kg, Non-rebreather=
2 other names for a rebreathing system
Semi-closed (partial rebreathing) or circle system
What is the flow rate formula for patients >7kg? Patients
>7kg= 30 ml O2/kg/min,
What is a VOC?
Vaporizer-out-of-circuit / Precision vaporizer
What kind of gases are VOC/Precision vaporizers used in?
High vapor pressure gases
What does it mean when it is said that the patient is receiving "fresh gas"?
Patient is receiving O2 saturated with anesthetic gas
If a precision vaporizer is VOC, then a non-precision vaporizer is ______
How does a VIC (non-precision vaporizer) differ from a VOC (precision vaporizer)?
*VIC is a draw over vaporizer, which means that the patient's breathing moves the O2 through the vaporizer and then volatizes gases (pt's breathing controls the % of anesthetic)
True or False: High vapor pressure gases may be used in a VIC (non-precision vaporizer)
False: Only low vapor pressure gases should be used in a non-precision vaporizer
What is the function of the reservoir bag?
Stores gases entering the system (patient can breath more easily from), allows for respiration rate, depth, and character to be observed during surgery, and allows us to manually ventilate our patient
What is PPV?
1. Positive Pressure Ventilation/ manual ventilation of the patient/ "bagging" the patient
Name the 2 main reasons why we need to do PPV
2. To blow-off excess CO2 for the patient and to prevent atalectasis
Formula for reservoir bag size
60ml x kg = nearest whole L
Why is the use of both unidirectional valves required on a breathing circuit?
To prevent the patient from rebreathing exhaled gases that contain CO2
What is the function of the inhalation unidirectional flutter valve?
To allow a one-way flow of gases to the patient
What is the function of the exhalation unidirectional flutter valve?
To allow a one-way flow of exhaled gases to re-enter the anesthetic machine
What is the function of the scavenge?
Prevents exhaled gases (that are in excess to the patient's requirements) from escaping into room air by safely directing and removing them from the patient, the breathing circuit and the anesthetic machine into the scavenger. OSHA required.
What are the 2 types of scavenge systems?
Active and Passive
How does the active scavenge work?
By using suction to draw gas from the machine and into the scavenger
How does the passive scavenge work?
By using the positive pressure of the gas in the machine to push the exhaled gases into the scavenge
What is the brand name for the passive scavenge?
What common substance is the passive scavenge made up of?
When should an F-air canister be changed?
After 12 total hours of use or once canister reaches 50 grams of waste
How should an F-air canister be stored?
In an upright position (especially when in use) without the bottom holes covered
What is the technical name for the "pop-off" valve?
Positive pressure relief valve
What is the function of the pop-off valve?
To vent excess gas, To prevent the build up pf pressure within the system
Name the only 4 reasons for the pop-off valve to ever be closed
1.To ventilate the patient* 2.To check for leaks in the system* 3.If using a 6 step NRB system 4.If using closed system anesthesia
What is the function of the CO2 absorbing canister?
To prevent the patient from rebreathing CO2
What are the 2 different kinds of granules that can be used in the CO2 absorbing canister?
Soda Lime granules or barium hydroxide lime granules
What is the function of the pressure manometer?
To measure the pressure of gases within the patient's breathing system, and therefore patient's airway and lungs.
When is the pressure manometer most often used?
When ventilating the patient and during leak checks
What pressure should not be exceeded when we ventilate or check for leaks in the system?
What is the negative pressure relief valve for?
It is a safety device only. It allows room air to enter the circuit.
What is another name for an F-circuit and what is it used for?
What is the name of the system when the pop-off is completely closed and all gases exhaled remain in the system?
Closed circle system (total rebreathing)
Two names for non-rebreathing systems
Ayres T Piece or Bain Circuit
3 steps to non-rebreathing system hook-up
1. adapter to outlet port from vaporizer 2. hook up scavenge 3. open pop-off valve on RB tubing
What is the disadvantage to a non-rebreathing system?
Does not incorporate the negative pressure relief valve
Why is the 6 step NRB system the safest of all 3?
It incorporates the use of the negative pressure relief valve
What is the purpose of performing a pressure check?
To ensure that the circuit is tightly sealed so that there's no leakage of gases into the room air