Pharmacology CST Exam Review
Local anesthesia - ANS involves injection of a nerve conduction-blocking agent into the tissues
surrounding a peripheral nerve or nerves that serve only tissue at the surgical site onset
happens between 5-15 minutes
Topical anesthesia - ANS involves the placement of a nerve conduction blocking agent onto the
skin or mucous membrane, i.e. cocaine HCL, onset is rapid
Monitored Anesthesia Care - ANS combination of nerve conduction blockade supplemented
with analgesics, sedatives, amnesics, used for patients with complex medical problems
Regional anesthesia - ANS involves the administration of an anesthetic along a major nerve
tract, blocks all nerve impulse conduction distal to the injection site, onset is slower than local
Nerve plexus block - ANS regional, agent is injected in the tissues surrounding a major nerve
plexus such as the brachial, cervical, caudal and lumbar
Spinal block - ANS regional, agent is injected into the CSF withing the subarachnoid space
Epidural block - ANS regional, Agent is injected into the space above the dura
Bier block - ANS regional, agent is injected into a vein in the arm that has been drained of blood
following placement of a tourniquet
General anesthesia - ANS involves an alteration in patients' perception of their environment
through alterations in their level of consciousness, accomplished by inhalation, injection,
instillation
What is stages/planes? - ANS Animals pass through a series of anesthetic stages and planes,
These stages correspond to changes in anesthetic depth, As animal passes through each
stage, there is a progressive loss of pain perception, motor coordination, consciousness,
reflexes, muscle tone and eventually cardiopulmonary function
Stage 1 - ANS Immediately after inhalation or injectable agent administered, Patient conscious
but disoriented, Decreased sensitivity to pain, All reflexes present, Patient may struggle, urinate,
defecate or show other signs of fear or anxiety
Stage 2 - ANS Begins with loss of consciousness, All reflexes present (may appear
exaggerated), Animal can chew and swallow (may yawn), Brain starts to lose control of
voluntary body functions, Animal may exhibit involuntary excitement: rapid limb movement,
vocalization, struggling, Breathing may be irregular or animal may appear to hold its breath,
, Potentially unpleasant for patient and hazardous to staff, Epinephrine release, cardiac
arrhythmias & arrest, Important to ensure smooth passage to Stage III
Stage 3 - ANS Subdivided into 4 planes - each indicates increasing anesthetic depth, Different
between animals, Remember effects of each drug when assessing depth of anesthesia,With
certain drugs, some reflexes are not lost
Plane 1 - ANS Light plane of anesthesia, Respiratory pattern becomes regular, Limb
movements cease, Eyeballs begin to rotate ventrally, Gag and swallow reflexes depressed
(intubation), Pedal and palpebral reflexes present but weaker
Plane 2 - ANS Medium plane of anesthesia (suitable for most surgical procedures), Eyeballs
rotate ventromedially, Respiration regular but shallow, RR, HR and BP decreased, Pedal and
swallowing reflexes lost, Laryngeal and palpebral reflexes are weakened or lost
Plane 3 - ANS Deep plane of anesthesia,HR, BP, and RR decrease; increase in CRT, Eyeball
position - central
Plane 4 - ANS Early anesthetic overdose, Marked drop in HR & BP, CRT is prolonged;
Abdominal breathing (inadequate ventilation),Pupils dilate; pupillary light reflex (PLR) is lost, Too
deep an anesthetic plane; animal in risk of cardiopulmonary arrest (CPA)
Stage 4 - ANS Respiration ceases Cardiac arrest Death Resuscitation of patient required
Induction Phase - ANS involves altering the patient's level of consciousness from a conscious
state to the unconscious state, can be carried out through IV induction agent or inhalation of
gaseous vapors, management and maintenance of the patients airway is critical
Maintenance Phase - ANS surgical intervention takes place, anesthesia provider monitors
changes in oxygen saturation, blood loss, muscle relaxation status, and cardiac status and
adjusts those levels accordingly
Emergence Phase - ANS occurs as surgical intervention is being completed, primary focus is
the monitoring of adequate and independent respiratory rate and function, reversal agents may
be given
Recovery Phase - ANS patient returns to the optimum level of consciousness and well-being
phase begins in OR until they are discharged
Aspiration - ANS inhalation of foreign fluid or solids into the lungs such as secretions or gastric
contents, occurs in patients where inadequate time for gastric emptying has elapsed
Cricoid Pressure - ANS reduces risk of aspiration, pressure is applied using thumb and index
finger to the cricoid cartilage
Local anesthesia - ANS involves injection of a nerve conduction-blocking agent into the tissues
surrounding a peripheral nerve or nerves that serve only tissue at the surgical site onset
happens between 5-15 minutes
Topical anesthesia - ANS involves the placement of a nerve conduction blocking agent onto the
skin or mucous membrane, i.e. cocaine HCL, onset is rapid
Monitored Anesthesia Care - ANS combination of nerve conduction blockade supplemented
with analgesics, sedatives, amnesics, used for patients with complex medical problems
Regional anesthesia - ANS involves the administration of an anesthetic along a major nerve
tract, blocks all nerve impulse conduction distal to the injection site, onset is slower than local
Nerve plexus block - ANS regional, agent is injected in the tissues surrounding a major nerve
plexus such as the brachial, cervical, caudal and lumbar
Spinal block - ANS regional, agent is injected into the CSF withing the subarachnoid space
Epidural block - ANS regional, Agent is injected into the space above the dura
Bier block - ANS regional, agent is injected into a vein in the arm that has been drained of blood
following placement of a tourniquet
General anesthesia - ANS involves an alteration in patients' perception of their environment
through alterations in their level of consciousness, accomplished by inhalation, injection,
instillation
What is stages/planes? - ANS Animals pass through a series of anesthetic stages and planes,
These stages correspond to changes in anesthetic depth, As animal passes through each
stage, there is a progressive loss of pain perception, motor coordination, consciousness,
reflexes, muscle tone and eventually cardiopulmonary function
Stage 1 - ANS Immediately after inhalation or injectable agent administered, Patient conscious
but disoriented, Decreased sensitivity to pain, All reflexes present, Patient may struggle, urinate,
defecate or show other signs of fear or anxiety
Stage 2 - ANS Begins with loss of consciousness, All reflexes present (may appear
exaggerated), Animal can chew and swallow (may yawn), Brain starts to lose control of
voluntary body functions, Animal may exhibit involuntary excitement: rapid limb movement,
vocalization, struggling, Breathing may be irregular or animal may appear to hold its breath,
, Potentially unpleasant for patient and hazardous to staff, Epinephrine release, cardiac
arrhythmias & arrest, Important to ensure smooth passage to Stage III
Stage 3 - ANS Subdivided into 4 planes - each indicates increasing anesthetic depth, Different
between animals, Remember effects of each drug when assessing depth of anesthesia,With
certain drugs, some reflexes are not lost
Plane 1 - ANS Light plane of anesthesia, Respiratory pattern becomes regular, Limb
movements cease, Eyeballs begin to rotate ventrally, Gag and swallow reflexes depressed
(intubation), Pedal and palpebral reflexes present but weaker
Plane 2 - ANS Medium plane of anesthesia (suitable for most surgical procedures), Eyeballs
rotate ventromedially, Respiration regular but shallow, RR, HR and BP decreased, Pedal and
swallowing reflexes lost, Laryngeal and palpebral reflexes are weakened or lost
Plane 3 - ANS Deep plane of anesthesia,HR, BP, and RR decrease; increase in CRT, Eyeball
position - central
Plane 4 - ANS Early anesthetic overdose, Marked drop in HR & BP, CRT is prolonged;
Abdominal breathing (inadequate ventilation),Pupils dilate; pupillary light reflex (PLR) is lost, Too
deep an anesthetic plane; animal in risk of cardiopulmonary arrest (CPA)
Stage 4 - ANS Respiration ceases Cardiac arrest Death Resuscitation of patient required
Induction Phase - ANS involves altering the patient's level of consciousness from a conscious
state to the unconscious state, can be carried out through IV induction agent or inhalation of
gaseous vapors, management and maintenance of the patients airway is critical
Maintenance Phase - ANS surgical intervention takes place, anesthesia provider monitors
changes in oxygen saturation, blood loss, muscle relaxation status, and cardiac status and
adjusts those levels accordingly
Emergence Phase - ANS occurs as surgical intervention is being completed, primary focus is
the monitoring of adequate and independent respiratory rate and function, reversal agents may
be given
Recovery Phase - ANS patient returns to the optimum level of consciousness and well-being
phase begins in OR until they are discharged
Aspiration - ANS inhalation of foreign fluid or solids into the lungs such as secretions or gastric
contents, occurs in patients where inadequate time for gastric emptying has elapsed
Cricoid Pressure - ANS reduces risk of aspiration, pressure is applied using thumb and index
finger to the cricoid cartilage
