Download Jacinda Christie, DVM Affiliated Emergency Veterinary Service

Jacinda Christie, DVM
Affiliated Emergency Veterinary Service
Overview
Respiratory anatomy/physiology
 Common causes of respiratory distress
 Initial assessment and stabilization
 Diagnostics/Therapies

Respiratory Anatomy

Upper airway
 Nasal passages
 Oropharynx
 Larynx
 Trachea

Lower airway
 Bronchi/Bronchioles
Respiratory Anatomy

Pulmonary parenchyma
 Lung tissue/interstitium
 Alveoli

Pleural space
Respiratory Physiology
Functions to deliver oxygen from the
environment to the blood stream
 Diffusion of oxygen from the alveoli,
across the interstitium, into the blood
stream

Respiratory Physiology
Total blood oxygen is a
combination of oxygen carried by
hemoglobin and dissolved oxygen
 Oxyhemoglobin saturation curve

 Hemoglobin saturation is directly
related to the partial pressure of
oxygen in the bloodstream
 Steep dropoff under SpO2 ~94%
Respiratory Physiology

Disruption in the delivery of oxygen from
the environment to the blood stream will
result in hypoxemia and lead to
respiratory distress
 Need to try to determine where this
disruption is occurring and correct it
Causes of Respiratory Distress

Upper airway disease
 Rhinitis
 Obstructive disease
○ inflammatory, abscess, polyp, foreign body,
neoplasia
 Laryngeal paralysis
 Collapsing trachea
Causes of Respiratory Distress

Lower airway disease
 Inflammatory
○ Chronic bronchitis, feline asthma
 Infectious
 Neoplasia
Causes of Respiratory Distress

Pulmonary parenchymal disease
 Cardiogenic and non-cardiogenic edema
 Pneumonia
○ Aspiration
○ Bacterial
○ Fungal
 Trauma
○ Contusions
○ Hemorrhage
 Neoplasia
 Coagulopathy
Causes of Respiratory Distress

Pleural space disease
 Trauma
○ Penetrating injury
○ Pneumothorax
○ Diaphragmatic hernia
 Cardiac disease
 Infectious
○ Pyothorax
○ FIP
 Coagulopathy
 Chylothorax
Non-respiratory Causes

Metabolic disease
 Acidosis – renal disease, DKA
Anemia
 Pain
 Pericardial disease
 Toxins

 MetHb, CO
Initial Assessment/Stabilization

Be prepared
 Oxygen source
○ Flow by, mask, cage
 IV catheter supplies
 Injectable medications
○ Diuretics, bronchodilators, sedatives,
glucocorticoids
 Inhaled medications
○ Bronchodilators, glucocorticoids
Initial Assessment/Stabilization

Hands off patient evaluation
 Signalment
 Brief health history
 Observation
○ Breathing patterns




Open mouth breathing
Normal rate vs. tachypnea
Paradoxical breathing
Inspiratory vs. expiratory
○ Stridor/stertor
○ Cyanosis
Initial Assessment/Stabilization

Breathing patterns
 Respiratory rate
○ Normal rate – upper airway disease
○ Tachypnea – short shallow breaths tend to be
associated with pulmonary parenchymal or pleural
space disease
 Paradoxical breathing
○ Lack of synchronous movement of the chest and
abdominal walls
 During normal respiration both the chest and abdominal
walls move outward
 Paradoxical breathing is characterized by the
abdominal wall being sucked in during inhalation
 Pleural space disease
Initial Assessment/Stabilization

Breathing patterns
 Inspiratory vs. expiratory
○ Prolonged inspiratory time, stridor/stertor
 Upper airway disease
○ Prolonged expiratory effort, wheezes
 Lower airway disease
○ Mixed inspiratory/expiratory
 Pulmonary parenchymal disease
Initial Assessment/Stabilization

Brief auscultation
 Heart murmur/arrhythmia
○ May indicate primary cardiac disease
 Crackles
○ Presence of fluid in the alveoli
 Wheezes
○ Narrowing of the airways
 Dull/muffled lung sounds
○ Pleural space disease
Disease localization
Respiratory distress
Upper airway disease
Yes
Loud upper airway sounds
No
Laryngeal paralysis
Collapsing trachea
Other
Thoracic auscultation
Increased lung sounds
Cardiac abnormalities
Consider heart
failure
Cardiac normal
Consider parenchymal
disease
Pneumonia, Hemorrhage,
Neoplasia, Inflammatory
Decreased lung sounds
Consider pleural
space disease
Pneumothorax
Effusion
Hernia
Initial Assessment/Stabilization

Oxygen support
 First therapy instituted
 Can be provided many ways
 Considerations
○ Stress level of patient
○ Size
○ Capabilities
Initial Assessment/Stabilization

Oxygen support
 Flow by
○ Easily provided in most situations
○ Short term
○ 25-40% FiO2
 Mask
○ Patient tolerance
○ Loose vs. tight fitting
○ Short term
○ 40-50% FiO2
Initial Assessment/Stabilization

Oxygen support
 Hood/Tent
○ E-collar with plastic wrap
○ Patient tolerance
○ Short or longer term
○ 40%+ FiO2
Initial Assessment/Stabilization

Oxygen support
 Oxygen cage
○ Clinic capabilities
○ Short and long term
○ 40%+ FiO2
Initial Assessment/Stabilization

Oxygen support
 Nasal cannula
○ Long term
○ Single or bilateral
○ Red rubber catheter
 Placed ventromedially
 Topical anesthetic
○ Humidify oxygen
○ 40-50% FiO2
Initial Assessment/Stabilization

Oxygen support
 Tracheal catheter/tracheostomy
○ Direct delivery of oxygen into the trachea
○ Consider in cases of severe upper airway
obstruction
Initial Assessment/Stabilization

Oxygen support
 Intubation
○ Severe respiratory distress
○ Upper airway disease
○ Can provide 100% FiO2
○ Can be helpful to maintain control of airway
while other emergency procedures are being
performed
 Tracheostomy, thoracocentesis, chest tube
placement
Initial Assessment/Stabilization

Vascular access
 Limit stress
 Peripheral IV catheter
○ Allows for administration of medications

Baseline bloodwork
 Minimum database or at least a big 4
Initial Assessment/Stabilization

Injectable medications
 Sedatives
○ Opioids – butorphanol,
buprenorphine
○ Benzos, Acepromazine
 Diuretics
○ Suspicion of CHF
 Glucocorticoids/Bronchodilators
○ Suspicion of feline asthma, chronic
bronchitis
Initial Assessment/Stabilization

Inhaled medications
 Aerokat/Aerodawg
 Easy to administer in an
emergency
 Bronchodilator
○ Albuterol
 Glucocorticoids
 Suspicion of feline asthma
or chronic bronchitis
Initial Assessment/Stabilization

Thoracocentesis
 Consider performing prior to obtaining
radiographs or other diagnostics
○ Paradoxical breathing
○ Dull lung sounds
○ Ultrasound confirmation of pleural space
disease
○ R/O coagulopathy
Initial Assessment/Stabilization

Thoracocentesis
 22g catheter or needle
○ Can use larger if needed
 Extension set
 3-way stopcock
 Syringe
Initial Assessment/Stabilization

Thoracocentesis
 Right and/or left hemithorax
 7-9th intercostal space
○ Directly in front of the rib
 Angle dorsally if air is expected
 Angle ventrally if fluid is expected
 Ultrasound guidance if available
 Local anesthesia and/or sedation as needed
Diagnostics

Radiographs
 Ensure patient is stable enough
 Continue supplemental oxygen
 Consider DV view rather than VD in stressed
patients
 Evaluation of cardiac size/VHS
○ Normal dogs <10.5-11.0
○ Cats 6.7-8.1
 Evaluate pulmonary pattern and pleural
space
Diagnostics

Bloodwork
 Minimum database once patient is stable
○ R/O anemia, severe metabolic disease as
causes of respiratory distress
 Coagulation panel
○ Especially if rodenticide toxicity or other
coagulopathy is suspected
 Blood gas
○ Ideal for evaluating how well the patient is
ventilating and determining the need for
manual ventilation
Diagnostics

Cytology
 Can be helpful for determining cause of
pleural effusion
Echocardiography
 Airway sampling

 TTW, BAL

Cardiac biomarkers??
Additional Therapies
IV fluids
 Antibiotics
 Nebulization
 ACE inhibitors/Pimobendan
 Pain management
 Plasma transfusion/Vitamin K1
 Chest tube placement
 Surgery

Summary
Respiratory distress is a common
presenting complaint
 Be prepared!
 Hands off and brief assessment can
help localize the disease and determine
the best initial therapy

Any Questions??