Midterm Flashcards
Allodynia
Pain caused by a stimulus that does not normally provoke pain
Analgesia
Loss of sensitivity to pain
Anesthesia
From greek word meaning insensibility to the entire or any part of the body
Balanced anesthesia
Combo of several drugs used to provide anesthesia ( usually one each addressed unconsciousness/amnesia, muscle relaxation, and analgesia)
General anesthesia
Loss of sensation to the entire body
Regional anesthesia
Loss of sensation in a larger, though limited body area ( usually blockade of specific nerves)
Local anesthesia
Loss of sensation in a prescribed body area ( blockage of specific nerve)
Surgical anesthesia
The stage/plane of general anesthesia that provides unconsciousness, muscle relaxation, and analgesia sufficient to allow painless surgery
Central sensitization
An increase in the excitability and responsiveness of nerves in the spinal cord
Circuit gas
The gases (O2 + anesthetic agent) the patient inhales and exhales and does not mix w/ ventilator drive gas
Drive gas
Gas a ventilator uses to deliver tidal volume
Eucarbia/Eucapnia
Normal CO2 concentration in patient’s blood with unit in mmHg and abbreviated as PaCo2
Expiratory time (expiratory pause)
Amount of time from completion of inspiration to initiation of the next breath
Hyperalgesia
Increased response to a stimulation that is normally painful wither at site of injury or in surrounding undamaged tissue
Hypercarbia/hypercapnia
Increased CO2 concentration in blood
Hyperesthesia/Hyperesthetic
Increased sensitivity to sensation
Hypoalgesia
Diminished sensitivity to pain
Hypocarbia/hypocapnia
Decreased CO2 concentration in blood
Hypoxemia
Decreased O2 concentration in blood’ may be due to lung disease, anatomical shunts, hypoventilation, ventilation/perfusion mismatch or breathing hypoxic gas measure…measured as PaO2
I:E ratio
Ratio of inspiratory time to expiratory time, goal to have >1:3 during ventilation
Inspiratory time
Amount of time required to deliver a tidal volume
Inspiratory pressure
Peak pressure required to deliver tidal volume and usually negative during normal breaking and positive when on a ventilator.
Line pressure
Supply pressure of gas used to drive a ventilator (50psi)
Minute volume
Tidal volume x RR measure in ml or L
Multimodal analgesia
Use of multiple drugs w/ different actions to produce optimal analgesia
Narcosis
Drug induced state of deep sleep from which patient may/may not be arousable
Narcotic
Agent that causes insensitivity or stupor…usually an opioid
Neuralgia
Pain in the distribution of a nerve or nerves
Neuritis
Inflammation of a nerve or nerves
Neuroleptanalgesia
Combo of a neuroleptic agent (tranq/sedative) and analgesic agent to produce state of heavy sedation and analgesia (ace+ morphine)
Neuropathy
Disturbance of function of pathologic change in a nerve
Nociception
Physiological components of pain; transduction, transmission, and modulation of neural signals generated in response to a noxious stimuli. Doesn’t include perception.
Nociceptor
Specialized nerve ending capable of encoding mechanical, chemical or thermal energy into electrical impulses
Nociceptor threshold
Min. strength of stimulus that will cause a nociceptor to generate nerve impulses
Opiate/Opiod
Class of drugs derived from opium poppy, can contain opium, or are produced synthetically
Pain
Unpleasant sensory and emotional experience associted w/actual or potential tissue damage, or described in terms of such damage.
Acute pain
Pain that follow bodily injury and disappears with healing..self-limiting
Cancer pain
Pain that can be acute, chronic or intermittent and related to the disease itself or to the treatment
Chronic pain
Pain that lasts several week to months beyond expected healing time and nonmalignant in origin
Neuropathic pain
Originates from injury or involvement of the peripheral or central nervous system. Burning, shooting and associated with motor, sensory or autonomic deficits (maybe).
Pathological pain
Pain that has an exaggerated response beyond its protective usefulness
Physiological pain
Pain that acts as a protective mechanism that incites individual to move away from the cause or avoid movement.
Somatic pain
Originates from damage to bone, joints, muscle or skin
Visceral pain
Arises from stretching, distension or inflammation of viscera
Peak inspiratory pressure
Peak airway pressure obtained when using IPPV with cmH20 as unit of measurement
Peripheral sensitization
Increase in excitability and responsiveness of peripheral nerve terminals
Positive End Expiratory Pressure
Airway pressure at end of exhalation and normally O but can be positive because of weight of bellows on ventilator
Preemptive analgesia
Administration of analgesic drug before painful stimulation to prevent sensitization of neurons improving postoperative analgesia
Reflex
Involuntary, purposeful and orderly responses to stimulus
Respiratory rate
Number of breaths/min
Sedation
State of CNS depression and drowsiness including reduced awareness of surroundings
Tidal volume
Amount of gas inhaled/exhaled with each breath measured in ml
Tranquilization
State of reduce anxiety & relaxation but still aware of surroundings
Assisted ventilation
Patient sets rate and ventilator senses initiation of breath by patient and trigger delivery of tidal volume to complete cycle
Controlled ventilation
Ventilator control both rate and tidal volume
Intermittent positive pressure ventilation
Artificial ventilation in which inspirations are provided by positive pressure applied to the airways..in contrast to negative pressure ventilation (manual or mechanical)
Manual ventilation
Person manually compresses rebreathing bag to breath for patient
Mechanical ventilation
Mechanical ventilator provides respiratory support
Wind-up
Temporal summation of painful stimuli in spinal cord mediated by C fibers and responsible for second pain
PaCO2
Carbon dioxide concentration in blood
PACO2
Carbon dioxide concentration in alveolar gas
ETCO2
Carbon dioxide tension in expired air
FiCO2
Carbon dioxide tension in inspired gas
PaO2
Oxygen concentration in blood
PAO2
Oxygen concentration in alveolar gas
Vt
Tidal volume
cmH20
Unit of measure for airway pressure and central venous pressure
torr
Unit of measure for arterial blood pressure and gas tension
mmHg
Unit of measure for arterial blood pressure and gas tension
psi
Unit of measure for compressed gases in cylinder or distribution systems
What are the reasons for giving premedication?
- Analgesia
- Decrease anxiety/stress
- Sedation-chemical restraint
- Minimize autonomic reflex activity
- Decrease anesthetic maintenance dose requirements
How do anticholinergic like atropine and glycopyrrolate work?
They competitively block acetylcholine on muscarinic receptors thereby minimizing autonomic reflex activity and reducing/preventing vagal effects like bradyarrhythmias and increased salivation/secretions (this part not useful in ruminants)
How can atropine and glycopyrrolate be administered, what is their onset of action and what is the difference in their cardiac effects?
SQ, IM, or IV
3-5 min for IV and 15 min for the others
Glycopyrrolate lasts 2-4 hours while atropine is only about 60-90 minutes
How do anticholinergic drugs treat bradycardia?
They increase the rate of spontaneous depolarization in the SA node (positive chornotrope) and increase transit speed though the AV node (positive dromotrope)
What are the undesirable effects of anticholinergics?
- Tachycardia and tachyarrhythmias
- Decreased GI motility (especially in horses)
- Miosis
- Bronchodilation
T/F: Atropine and glycopyrrolate can cross the blood brain barrier and enter into the placenta.
False. Glycopyrrolate can not cross the BBB or enter into the placenta.
Which anticholinergic has more pronounced effects and is better use in emergency situations?
Atropine
Which anticholinergic is rapidly metabolized in rabbits and why?
Atropine as rabbits have an enzyme, atropinase
What are the premedication effects of anticholinergics?
They decrease autonomic reflex activity. They no not have alagesic properties, decrease anxiety, sedate, or decrease anesthetic requirements.
What types of phenothiazines/butyrophenones do we use and what do they do?
Acepromazine, Droperidol and Torbugesic
They are tranquilizer that block dopamine receptors in the basal ganglia and limbic system and the alpa 1 adrenergic receptors causing vasodilation.
Which drug is the best used in combination with phenothiazines?
Opiods
What other effects besides being a tranquilizer do phenothiazines have?
- Decrease anesthetic requirements
- Reduce indicense of some adverse effects of other drugs like acting as an antiemetic, antihitaminic, and antiarrhythmetic
How are phenothiazines administered, what is their onset and duration?
IM or IV..oral at home Slow onset (15-20min) Long duration (2-4 hours)
What affects do phenothiazines have on the body?
- Hypotension and CO reduction
- Splenic sequestration of RBC ( decrease PCV)
- Antiemetic, delays gastric emptying and reduces lower esophageal sphincter tone
- Antihistamine
- May decrease seizure threshold
- Penile prolapse in stallions
- No analgesia
What is the maximum dose in dogs for acepromazine? What is the recommended dose?
3-4mg
0.01-0.1 mg/kg
What is the discrepancy between the labeled dose of acepromazine and the clinical dose?
The labeled dose is 10x higher, so don’t do that.
When should you not use ACE?
- Neonates
- Geriatrics
- Shocky/hypovolemic patients
- Risk of hemorrhage
- Boxers
what id the most common adverse effect of giving acepromazine?
Hypotension due to alpha 1 adrenergic receptor blockage
Why would you not want to give acepromazine to a patient that you need to do skin testing on?
It is an antihistamine and will mess up the result
How do benzodiazepines work?
They potentiate the effects of GABA at the GABA receptor site which increases the frequency of CL channels opening leading to the hyper polarization of the membrane and reducing neuronal excitability.
What do we use Diazepam and midazolam in the clinical setting?
- Mild sedatives ( enhances sedation/restraint when used with opioids)
- Central muscle relaxant
- Anticonvulsant (very effective)
- It reduces the dose of injectable and inhalant anesthetics
- High safety margin
Which drugs would you use in combination sight benzodiazepines?
A2 adrenergic receptor agonistic drugs like xylazine, detomidine, medetomidine, dexmedetomidine and atipamezole and opioids
What are the important differences between diazepam and midazolam?
Diazepam is not water soluble so it doesn’t mix well with most other drugs except ketamine and it is erratically absorbed and irritating if given IM.
Midazolam is well absorbed when given IM or SQ, its compatible with many other premeds and only need to give one IM injection.
What is the onset and duration of action of benzodiazepines?
Rapid onset if IV, but midazolam is rapid following IM as well. Diazepam lats several hours while midazolam last a couple hours.
If you are premedicating a neonate or geriatric patient, would you use acepromazine or benzodiazepines?
Benzodiazepines
What is the drug of choice for emergency seizure treatment?
Diazepam
What drug can be used to reverse the effects of benzodiazepines?
Flumazenil
Why are benzodiazepines so safe to use?
They only enhance the binding capability of GABA to the alpa subunit, so they will only be effective if there is GABA available to bind. Also, the reduce cardiopulmonary effects because you don’t have to use as much of other drugs that can cause these adverse cardio effects.