ANESTHETIC PROBLEMS AND EMERGENCIES
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Transcript ANESTHETIC PROBLEMS AND EMERGENCIES
ANESTHETIC PROBLEMS
AND EMERGENCIES
CHAPTER 12
Every anesthetic procedure
has the potential to cause
death of the animal
Emergencies are uncommon and
the overwhelming majority of
patients recover from anesthesia
with no ill lasting effects
WHY,WHY,WHY
DO ANESTHETIC PROBLEMS AND EMERGENCIES ARISE?
1. HUMAN ERROR!
HUMAN ERROR
FAILURE TO OBTAIN AN ADEQUATE
HISTORY OR PHYSICAL
EXAMINATION ON THE PATIENT.
*Ideally, every patient scheduled for
anesthesia should have a complete physical
examination, and a thorough history should
be obtained with the owner present.
Less than ideal circumstances are
common:
Owner drops patient off in a hurry
Patient brought in by neighbor or friend
Receptionist takes the history
Physical exam is cursory or omitted
HISTORY?
PHYSICAL?
HUMAN ERROR
LACK OF FAMILIARITY WITH THE
ANESTHETIC MACHINE OR DRUGS
USED
The not so confident kennel worker who was
asked to assist in surgery today.
The confident, knowledgeable, experienced
RVT!
HUMAN ERROR
INCORRECT ADMINISTRATION OF DRUGS
INACCURATE WEIGHT
MATHEMATICAL ERRORS
USE OF WRONG MEDICATION
*Be aware of medications that come in different
concentrations
ADMINISTRATION OF MEDS BY INCORRECT ROUTE
*knowledge of pharmacology
*drugs with narrow margin of safety
CONFUSION BETWEEN SYRINGES
*ALWAYS LABEL SYRINGES
USE OF INAPPROPRIATE SYRINGE SIZE
HUMAN ERROR
PRESSURES AND
DISTRACTIONS
Feeling hurried or rushed
Distraction because of ineffective multitasking
Fatigue
Inattentiveness
Be proactive, rather than reactive!
Recognize early signs of trouble
Pay attention to patient and machines
WHY,WHY,WHY
DO ANESTHETIC PROBLEMS AND EMERGENCIES ARISE?
2.
EQUIPMENT
FAILURE
*In many
cases the failure of
the machine is in
fact a failure of the
operator.
EQUIPMENT FAILURE
CO2 ABSORBER EXHAUSTION
*In re-breathing systems, if CO2 is not
removed from the circuit, the patient
will experience hypercapnia.
* In a non re-breathing system, if the gas flow
is too low, there may also be a significant rebreathing of expired gases.
↑ CO2 = Tachypnea, tachycardia, brick
red mucous membranes, cardiac
arrhythmias, respiratory acidosis
Human error!
EQUIPMENT FAILURE
INSUFFICIENT O2 FLOW
You will need to check both the flowmeter and
the oxygen tank pressure gauge.
Oxygen tank runs out
Hose becomes disconnected
Obstruction or leak occurs
*If the oxygen flow stops while the patient is hooked
up to a non re-breathing system, the anesthetist
should disconnect the hose from the Endotracheal
tube, allowing the patient to breathe room air.
• If a re-breathing (circle) system is being used, the
patient can remain connected for a short period of
time, provided the reservoir bag remains inflated.
Human Error
EQUIPMENT FAILURE
ANESTHETIC MACHINE
MISASSEMBLED
Take time to learn and follow the
direction and path of gas flow within
the machine. Every time a connection
is added or removed, the anesthetist
should ensure that the correct pattern
of flow is maintained and that all
connections are secure.
**Soda-Lyme container main leak
EQUIPMENT FAILURE
ENDOTRACHEAL TUBE PROBLEMS
BLOCKED TUBES
Twisting or kinking of the tube (inappropriate
positioning)
Accumulation of material such as blood, saliva,
excess lubricant
Tube advanced too far into a bronchus
CHECK TUBE FUNCTION:
BAG the patient – watch for chest rising
Disconnect the patient – feel for air coming out of
the tube when the patient’s chest is compressed
If an accumulation of material is causing the obstruction, it
may be helpful to suction with a syringe through a redrubber catheter or feeding tube.
EQUIPMENT FAILURE
VAPORIZER PROBLEMS
Wrong anesthetic in the vaporizer
Vaporizer is empty
Do not tip the vaporizer – could result
in leakage into the oxygen bypass
Vaporizer dial may be jammed
Don’t overfill the vaporizer
EQUIPMENT FAILURE
POP-OFF VALVE PROBLEMS
The pop-off valve is inadvertently left closed
Closed pop-off valve →pressure rises in the
circuit →reservoir bag expands, as well as the
patient’s lungs →exhalation is prevented
*This can lead to decreased cardiac output, low blood
pressure, and death.
If pressure rises in the circuit and
the bag is full and tight, the
anesthetist should attempt to open
the pop-off valve and/or decrease
the oxygen flow rate.
WHY,WHY,WHY
DO ANESTHETIC PROBLEMS AND EMERGENCIES ARISE?
3. ANESTHETIC AGENTS
Every injectable or inhalation agent has
the potential to harm a patient and, in
some cases, cause death. Review the
description of the pharmacologic and
physiologic effects of pre-anesthetic and
general anesthetic agents in chapters 1
and 3.
WHY,WHY,WHY
DO ANESTHETIC PROBLEMS AND EMERGENCIES ARISE?
4. PATIENT FACTORS
PATIENT FACTORS
GERIATRIC PATIENTS
(75% of life expectancy)
POTENTIAL PROBLEMS
Reduced organ function- liver, kidney, heart
Poor response to stress
At risk for degenerative disorders- diabetes,
CHF, cancer
Increased risk for hypothermia and
overhydration
Prolonged recovery
Geriatric Patients solutions
POTENTIAL SOLUTIONS
Reduce anesthetic dosages
Increase preanesthetic blood work
from mini to a general profile, include
u/a, x-rays, ECG if needed
Allow a longer time for response to
drugs
Reduce fluid rate
Keep patient warm
Choose anesthetic agents with
minimal CV effects
Pre-oxygenate
PATIENT FACTORS
PEDIATRIC PATIENTS
(<3 months)
POTENTIAL PROBLEMS
Increased risk for hypothermia and overhydration
Increased risk of hypoglycemia, hypotension, Bradycardia
Inefficient excretion of drugs-reduced kidney and liver
function
Difficult intubation
Difficult IV cath placement
POTENTIAL SOLUTIONS
Be proactive about heat preservation
Avoid prolonged fasting (+/- 5% dextrose
administration)
Reduce anesthetic dosages
Use a gram scale to weigh
Use inhalant anesthetics
PATIENT FACTORS
BRACHYCEPHALIC DOGS
POTENTIAL PROBLEMS
Conformational tendency toward airway
obstruction
Abnormally high vagal tone
Elongated soft palate
Small nasal openings
Hypoplastic trachea
Difficult to intubate
Bradycardia
POTENTIAL SOLUTIONS
Use an anticholinergic
Pre-oxygenate
Induce rapidly with IV agents
Delay extubation
Close monitoring during recovery- recover in a
excitement free area
PATIENT FACTORS
SIGHTHOUNDS
POTENTIAL PROBLEMS
Increased sensitivity to barbiturates
Lack of body fat for
redistribution/elimination
of the drug
POTENTIAL SOLUTIONS
Use alternative agents
PATIENT FACTORS
OBESE PATIENTS
POTENTIAL PROBLEMS
Accurate dosing is difficult- lower dose /kg
Poor distribution of drugs
Respiratory difficulty- shallow rapid
respirations during anesthesia
POTENTIAL SOLUTIONS
Dose according to ideal weight
Pre-oxygenate
Induce rapidly
Delay extubation
Close monitoring during recovery
PATIENT FACTORS
CESAREAN PATIENTS- normally an emergency
POTENTIAL PROBLEMS
DAM: increased workload to heart
Respiration compromised
Increased risk of hemorrhage- shock/hypotension
Increased risk of vomiting/regurgitation- not
normally fasted
Hypoxemia
Hypercarbia
Acid/base imbalance
Tissue trauma
Cardiac arrhythmias
OFFSPRING: susceptibility to the effects of the
anesthetic agents (reduced Cardio and Respiratory
function)
Cesarean patients
POTENTIAL SOLUTIONS
DAM: IV fluids
Clip patient before induction, in
lateral recumbency
Pre-oxygenate
Reduce anesthetic dosages
OFFSPRING: use doxapram and/or
atropine
aspirate fluids from mouth
Administer oxygen via face mask,
intubate with 18 or 16g IVC
Keep warm
Encourage nursing
Patient Factors
TRAUMA PATIENTS
POTENTIAL PROBLEMS
Respiratory distress commondecrease in tidal volume, increase in
CO2
Cardiac arrhythmias
Shock and hemorrhage- hypotension
Internal injuries
POTENTIAL SOLUTIONS
Stabilize patient if possible
Obtain chest rads, ECG
Check for other concurrent injuries
Anesthetic Problems and
Emergencies: Patient Factors
Change in blood pressure
Resulting from a change in cardiac output or
vascular tone
Anesthetic depth will affect both parameters
Hypotension → decreased tissue perfusion →
tissue hypoxia/anoxia → anaerobic glycolysis →
lactic acid production → acid/base imbalance
Monitor blood pressure closely
Doppler or oscillometric methods
Digital pulse palpation
Capillary refill time
TREATMENT OF HYPOTENSION
REDUCE ANESTHETIC DEPTH
PRESERVE WARMTH
FLUID THERAPY- SHOCK RATE
ADMINISTRATION OF EMERGENCY
DRUGS:
Corticosteroids
Sodium bicarbonate
Cardiac inotropes (dopamine,
dobutamine, ephedrine)
Fluid Therapy for Hypotension
Crystalloid fluid administration
May have to deliver small boluses for
rapid therapy
Crystalloid fluids stay in intravascular
space
<2 hours
Watch for fluid overload, especially in
cats
Monitor heart rate, blood pressure,
mucous membrane color, and capillary
refill time
Fluid Therapy for Hypotension
(Cont’d)
Colloid fluid administration
Helpful if blood pressure can’t be
maintained
Remain in the intravascular space longer
than crystalloids
Will increase colloidal osmotic pressure
and help stabilize blood pressure
Given in smaller volume in conjunction
with crystalloids
Hetastarch, Dextran 40 or 70, 10%
Pentastarch, plasma, whole blood
Respiratory problems in the trauma patient
Direct trauma to the chest leading to
lung collapse or failure of alveolar gas
exchange
Must remove air/fluid from chest cavity
prior to anesthesia
Deliver supplemental oxygen
Oxygen delivery methods
Flow-by-oxygen
Nasal catheters
Oxygen collars
Thoracocentesis (Chest Tap)
To relieve pneumothorax or pleural effusion from
chest cavity
Performed by veterinarian Prepped by veterinary
technician
Temporary bandage over chest wound
Place animal in sternal recumbency or standing
position
Shave lateral chest wall between the 7th and 9th
intercostal spaces caudal to point of the elbow
Aseptically prepare 4 cm × 4 cm area
Prepare a 20- to 22-gauge, 1- to 1½-inch
catheter with a three-way stopcock and large
syringe
video
PATIENT FACTORS
CARDIOVASCULAR DISEASE
POTENTIAL PROBLEMS
Circulation compromised
Pulmonary edema common
Increased tendency to develop arrhythmias
and tachycardia
POTENTIAL SOLUTIONS
Alleviate pulmonary edema (diuretics)
Pre-oxygenate
Avoid agents that may cause arrhythmias
Prevent overhydration- cut fluids in 1/2
Preexisting cardiovascular disease
Anemia
Shock
Cardiomyopathy (primary or
secondary)
Congestive heart disease (mitral valve
insufficiency)
Heartworm disease
Coexisting imbalances (e.g., hypoxia,
hypercapnia, electrolyte imbalances)
Bradycardia
Most common cardiac anesthetic
problem
Caused by preanesthetic or anesthetic
drugs
Force of cardiac contraction may also
be decreased
Blood return to the heart may be
decreased (preload)
Treat with drugs or adjustment of
anesthetic depth
Cardiac arrhythmias
Caused by anoxia/hypercarbia, poor
tissue perfusion, acid/base imbalance,
myocardial damage
Difficult to detect on physical
examination; may find dropped beats
Diagnose with ECG and report
immediately to veterinarian who will
determine the treatment required
Concurrent pulmonary disease is
sometimes seen
PATIENT FACTORS
RESPIRATORY DISEASE
POTENTIAL PROBLEMS
Poor oxygenation of tissues
Patient may be anxious and difficult to
restrain
Increased risk of respiratory arrest
POTENTIAL SOLUTIONS
Avoid unnecessary handling
Pre-oxygenate
Induce with injectable agents
Intubate rapidly; control ventilation
Monitory closely during recovery
Respiratory disease
Caused by:
Pleural effusion
Pneumothorax
Tracheal collapse
Clinical signs
Tachypnea
Dyspnea
Cyanosis
Diaphragmatic hernia
Pneumonia
Pulmonary edema
Anesthetic considerations
VT is reduced and respiratory rate is
decreased in most anesthetized animals
A decrease in VT will result in a decreased
alveolar gas exchange
Lighten anesthesia as much as possible in a
patient with respiratory disease
Provide intermittent ventilation
Evaluate oxygen-carrying capacity with PCV
or pulse oximeter
Preoxygenation is necessary prior to
induction
Diaphragmatic Hernia
Dysnpnea- pre oxygenate
Avoid head down positions
Intubate rapidly
“bagging” patient
Pay close attention to pulse ox,
capnograph, and do a arterial blood
gas if available.
PATIENT FACTORS
HEPATIC DISEASE
POTENTIAL PROBLEMS
Liver necessary for drug metabolism, blood clotting factors,
plasma proteins, carbohydrate metabolism
Decreased synthesis of clotting factors
Possibly hypoproteinemic
Dehydration common
Anemic and/or icteric
Prolonged recovery
POTENTIAL SOLUTIONS
Pre-anesthetic blood work
Preanesthetic agents must be chosen with care
Use inhalant anesthetics
Close monitoring during recovery
Preanesthetic agents must be chosen with care
PATIENT FACTORS
RENAL DISEASE
POTENTIAL PROBLEMS
Delayed excretion of anesthetic agents
Electrolyte imbalances common
Dehydration may be present
POTENTIAL SOLUTIONS
Pre-anesthetic blood work
Rehydrate before surgery
Reduce anesthetic dosages
IV fluids
Renal disease
Kidneys maintain volume and electrolyte
composition of body fluids
Renal excretion removes anesthetic
agents and metabolites from the body
General anesthesia is associated with
decreased blood flow to the kidneys
Diagnosis: urine specific gravity, BUN,
creatinine
Offer water up to 1 hour prior to
premedication
Correct dehydration prior to anesthesia
Anesthetic Problems and Emergencies:
Patient Factors (Cont’d)
Urinary blockage
Clinical signs
Depression
Dehydration
Uremia
Acidosis
Hyperkalemia (can lead to cardiac arrest)
Inhalation agents are less hazardous
for the patient
ANESTHETIC PROBLEMS AND EMERGENCIES
Anesthetic problems will inevitably occur at some
point in your career. No anesthetic experience is
the same, so beware of the false sense of security!
ANESTHETIC PROBLEMS AND
EMERGENCIES
The Role of the Veterinary Technician
in Emergency Care
ANIMALS THAT WILL NOT STAY ANESTHETIZED
Animals won’t stay anesthetized
Check vaporizer setting
Check level of anesthetic in the vaporizer
Proper ET tube placement or air leakage around it
Patient apnea
Shallow respirations
Proper assembly of anesthetic machine with tight
connections
Adequate oxygen flow
Anesthetic machine/vaporizer is working properly
Agonal breathing vs. light plane breathing
ANIMALS THAT ARE TOO DEEPLY ANESTHETIZED
Animals are too deeply anesthetized
<6 bpm; shallow respirations, dyspnea
Pale/cyanotic mucous membranes
Capillary refill time >2 seconds
Bradycardia
Weak pulse; systolic blood pressure <80 mm Hg
Cardiac arrhythmias; irregular QRS complexes
or VPCs
Hypothermia
Absent reflexes
Flaccid muscle tone
Dilated pupils
TREATING EXCESSIVE
ANESTHETIC DEPTH
ADJUST THE VAPORIZER:
NOTIFY THE VETERINARIAN:
BAG THE ANIMAL
1. Close the pop-off valve
2. fill the reservoir bag with oxygen
3. gently squeeze the bag until the
patient’s chest rises slightly (15-20 cm
H2O)
4. Repeat until animal shows signs of
recovery
PALE MUCOUS MEMBRANES
Pale mucous membranes
Preexisting conditions
Blood loss during surgery
Anesthetic agent that causes
vasodilation and hypotension
Hypothermia
Pain
TREATMENT OF PALE MUCOUS
MEMBRANES
Ascertain the animal’s anesthetic
depth:
HR, RR, pulse quality, CRT
Consult the veterinarian
Fluids, blood transfusion
Anesthetic Problems and
Emergencies (Cont’d)
Prolonged capillary refill time (>2
seconds)
Blood pressure cannot adequately
perfuse superficial tissues
May result from conditions present
prior to induction
May be secondary to blood loss during
surgery
May be seen in animals in deep
anesthesia
DYSPNEA AND/OR CYANOSIS
DYSPNEA: respiratory difficulty
CYANOSIS: bluish coloration of the mucous
membranes indicating inadequate tissue
oxygenation
Assessment
Respiratory character and volume
Depth of anesthesia
Associated with pain
Proper ET tube placement
ET tube blockage
Oxygen saturation
Arterial or end-tidal CO2
Treatment of
cyanosis/dyspnea
1. Check O2 flow meter
2. Turn off vaporizer and begin to bag
the patient (IPPV)
If the anesthetic machine is unavailable, an
Ambu bag can be used to deliver room air
3. Reintubate if necessary
4. Continue until patient improves
5. Close monitoring to ensure that
cardiac arrest does not occur
Radiographs and thoracocentesis might be
needed
TACHYPNEA
TACHYPNEA: rapid respirations
CAUSES:
Surgical stimulation
Commonly seen with opioid use
Associated with light anesthesia
accompanied by tachycardia and
spontaneous movement
May be seen in hyperthermic animals
TREATMENT OF TACHYPNEA
CHECK ANESTHETIC DEPTH
Is the animal too light?
CAPNOGRAPH READING
Obese patients
Assist or control ventilation
RESPIRATORY ARREST
Not all cases require immediate action
by the anesthetist:
Cessation of respiratory efforts
Can lead to cardiac arrest
Temporary arrest
May follow injection of respiratory depressants
or following a period of prolonged bagging
Evaluate other vital signs
HR/pulse quality:
MM:
ECG
Pulse oximeter reading:
Respiratory arrest (Cont’d)
True arrest
Requires immediate action
Can result from anesthetic overdose,
cessation of oxygen flow, or preexisting
respiratory disease
May be preceded by dyspnea or cyanosis
and abnormal vital signs
May use Ambu bag, mouth-to-ET tube, or
mouth-to-muzzle resuscitation
Use of an Ambu Bag
TREATMENT OF TRUE RESPIRATORY
ARREST
1. NOTIFY THE VETERINARIAN
2. Turn off the vaporizer
3. Place ET tube if not already done
Emergency tracheotomy?
http://www.youtube.com/watch?v=3doQewrHdh
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4.Monitor for cardiac arrest
5.Restore oxygen flow and begin bagging
the patient
6. Continue bagging every 5 seconds until
vital signs improve
7. Administer shock fluids
8. Preserve warmth
CARDIAC ARREST
Cardiac arrest
No heartbeat is auscultated or palpated
Normal QRS complexes are absent
No arterial pulse and blood pressure <25 mm
Hg
Gray or cyanotic mucous membranes
Widely dilated pupils, no corneal reflex
Agonal breathing
Some prior warning is usually present
Respiratory distress or arrest,
cyanosis/dyspnea, prolonged capillary refill
time, arrhythmia
CARDIAC ARREST - ABCDEF
There is a critical 4 MIN window to
restore oxygen delivery to the brain!
Five people (ideal) involved
1 performs chest compressions
2 bags the animal
3 assesses the pulse during compressions and
checks the pulse or ECG when compressions
are stopped
4 draws up and administers drugs as per the
veterinarian’s instructions
5 maintains a record of the patient’s status
and resuscitative treatment
Anesthetic Problems and
Emergencies
Cardiac arrest with CPCR
A = airway
B = breathing
C = circulation
D = drugs
E = ECG
Circulation is the most important
step so the correct order is CABDE
CARDIAC ARREST - ABCDEF
AIRWAY and
BREATHING;
IMMEDIATELY CALL FOR HELP, NOTE THE
TIME!
An Endotracheal tube must be
placed!
Begin bagging at 1 breath every 1012 seconds
Do not overinflate
CARDIAC ARREST - ABCDEF
CIRCULATION – cardiac
compressions should be initiated
POSITIONING: right side down with
feet toward the compressor
LARGE DOGS: The heel of the
compressor’s hand should compress the
chest against a firm object placed under
the dog’s chest just behind the elbow.
Also, dog can be placed in dorsal
recumbency and compression applied to
the caudal 1/3 of the sternum
CARDIAC ARREST - ABCDEF
Medium sized dogs: The chest is
compressed between two hands,
one underneath the chest and the
other at the 5th intercostal space
over the heart itself.
Small dogs or cats: compression
applied using the thumb to
compress the chest against the
fingers of the same hand.
Circulation
Most important factor is return of
spontaneous circulation (ROSC)
Cardiac compressions
Method depends on the size of the animal
Compress chest about 1/3 the diameter of the
chest wall
1-2 compressions/second generates 100 bpm
heart rate
Compressions manually force blood through the
heart and into tissues
Each compression should produce a palpable
femoral pulse
Circulation (Cont’d)
Bag the patient every 10-12 seconds
Simultaneously with compressions
Some results should be seen within 2 minutes
Internal compressions may be necessary
Resuscitation is unlikely to be successful after
15 minutes
Once spontaneous cardiac contractions are
established, continue bagging until
spontaneous breathing is established (several
hours)
These patients are not on their
right side- boooo
CARDIAC ARREST - ABCDEF
Drugs
Veterinarian authorizes dosage, route,
and nature of drugs
Catheterized animals
Drugs administered IV followed by rapid
fluid administration
Be careful of overhydration
Injections into the base of the tongue
or by the intratracheal route are the
second choice
Intracardiac injections should be
avoided
Commonly used drugs
Epinephrine
Vasopressin
In place of or alternated with epinephrine
Atropine
Cardiac arrest
Anesthesia-related cardiac arrest
Dopamine or dobutamine
Increase force and rate of cardiac
contractions
Monitor cardiovascular and respiratory
function
Blood pressure, blood gases, pulse
oximetry, ECG, capnography
Drug and fluid therapy varies
Assess brain function
Repeat arrest within 24 hours is
common
Following successful ROSC, other
conditions may arise
Pulmonary or cerebral edema
CARDIAC ARREST - ABCDEF
ECG
Periodically check for spontaneous
contractions by discontinuing external
compression and either palpating for a
pulse or looking for QRS complexes on
the ECG.
Differentiate between different forms of
cardiac arrest to more effectively pick
the treatment
ECG
Don’t use alcohol if a defibrillator is
present
Asystole
Ventricular fibrillation
No electrical activity
Coarse vertical zig-zag lines resulting
from disorganized muscular heart activity
Pulseless electrical activity
(electromechanical dissociation, EMD)
Normal or near-normal complexes
Regurgitation during anesthesia
A passive process under anesthesia
No retching, just fluid draining from animal’s
mouth or nose
Stomach contents may be aspirated into
respiratory tract
Most common occurrence in head-down
surgical positions and in ruminants
Treatment
Immediate placement of cuffed ET tube
Clean out regurgitated material with suction
Vomiting during or after anesthesia
Common in brachycephalic dogs or nonfasted animals
An active process usually accompanied by retching
Usually occurs as the animal is losing or regaining
consciousness
Signs
Airway obstruction leading to dyspnea/cyanosis,
bronchospasm
Treatment
Intubation and suction if unconscious
Lower head and clean oral cavity if conscious
Seizures
Seen with ketamine administration, after
diagnostic procedures (myelography), or
preexisting conditions
Signs
Spontaneous twitching; uncontrolled
movements of head, neck, and limbs;
opisthotonus; triggered by a stimulus
Treatment
Reduce stimuli, postoperative analgesia,
diazepam or propofol, monitor for
hyperthermia
Excitement
Seen after barbiturate anesthesia or
high opioid doses, as spontaneous
paddling and vocalization
Treatment may not be necessary
Sedatives may help
Naloxone can reverse opioids
Seizures should be differentiated
from excitement
Dyspnea in cats
Dyspnea is usually caused by laryngospasm
sometimes triggered by removal of the ET
tube
Laryngeal edema may result from repeated
intubation attempts
May breathe with an audible stertor (wheeze)
during inspiration
Differentiate from growling during expiration
May resolve itself or may need oxygen
administration via facemask, intubation, or a
tracheotomy
Is easier to prevent than treat
Dyspnea in dogs
Breed-related
Airway obstruction
Brachycephalic dogs
Anatomy, foreign objects, postsurgical
tissue swelling
Humidified oxygen can be delivered to
an awake animal
By facemask, nasal cannula, E-collar, or
oxygen cage/tent