SA Respiratory Emergencies Flashcards
Respiratory distress is considered
Physically labored respiration
Define dyspnea
a subjective experience of
breathing discomfort that consists of qualitatively distinct sensations that vary in intensity
It includes:
- increased work of breathing
- Air hunger –> stretching out neck
- sensation of chest “tightness”
How can one identify respiratory distress?
Increased respiratory rate
Increased respiratory effort
Orthopnea –> elbows out
Open mouth breathing –> not panting tho
Cyanosis
Stridor
Occasionally signs may not be as obviously
T/F Respiratory distress is considered a Common cause of presentation to ER.
True
Respiratory distress is..
Life threatening and causes patient and owner distress
What are some physiologic dysfunctions that result when respiratory distress occurs?
- Hypoxemic
respiratory failure –> not getting enough O2 in circ - Hypercapnic
respiratory failure –> not getting rid of CO2
What is hypoxemia?
- Partial pressure of oxygen in blood (PaO2) of less than
<80mmHg - SpO2 (percent oxygen saturation) <95%
What is normal PaO2 and SpO2?
Normal PaO2 is 80-100mmHg, normal SpO2>95%
Life threatening (severe) hypoxemia is:
PaO2<60mmHg, SpO2<90%
How do you measure PaO2 and SpO2?
PaO2–> measured by arterial blood gas
SpO2 –> measured by pulse
oximetry
SaO2 –> measured by arterial
blood gas
What 2 forms is oxygen dissolved in?
- Dissolved in blood (PaO2)
- Carried by hemoglobin (SpO2 or SaO2)
90 SpO2 correlates to 60 PaO2 –> not great
Under GA and intubation your PaO2 is what? and your spO2 is what?
PaO2 is 500 and spO2 is 100%
What is Pulse Oximetry used for?
- Differential absorption of infrared light by oxygenated and deoxygenated Hb
- 2 wavelengths of light (red and
infrared) used - Oxygenated Hb absorbs more infrared light
What are the two types of pulse ox available?
Transmissive probe
Reflectance probe
Describe the transmissive probe
- Most commonly used
- Sites: lip, tongue, pinna, toe webbing, prepuce, vulva
- Can be challenging in awake
patients
Describe the reflectance probe.
- Often better tolerated
- Must be used over a bony surface
- EX: Tail base, rib, metacarpal area, metatarsal
area
What are some limitations of pulse oximeters?
Affected by:
- Ambient light
- Peripheral vasoconstriction
- Darkly pigmented skin –> chows and sharpies
- Hypothermia/hypoperfusio
- Anemia
- Tachycardia
- Hyperbilirubinemia
Poorly tolerated in awake patients
Abnormal Hb species
Carboxyhemoglobin
- Falsely high SpO2, absorbs little IR light
MetHb
- Pulse Ox defaults to 85%, both forms absorb equally well
In order for pulse oximeters to work they must be:
- Over an area of pulsatile blood flow
- Patients heart rate must match pulse oximeter reading
What is arterial blood gas?
- The gold standard to measure PaO2, SaO2, PaCO2, pH and
more! - Sites: Dorsal pedal, femoral, coccygeal, sublingual, dorsal auricular in dogs. Femoral in cats!
- Can be technically challenging and painful
- Need special equipment to run samples
What is cyanosis?
- Grayish to bluish discoloration of mucous membranes
- Deoxygenated Hb concentrations >5mg/dL (Normal Hb 13-20mg/dL) needed for for cyanosis to be visualized reliably
- Can be affected by anemia
- Affected by room lighting and visual acuity
- Pink is not always good!
What are causes of hypoxemic respiratory failure?
Pneumothorax
hemothorax
pleural effusion
pneumonia
pulmonary edema
pulmonary contusion
pulmonary thromboembolism
What is hypercapnic respiratory failure?
Ventilatory failure:
- Respiratory center
- Diaphragm
- Intercostal muscles
- Upper airway obstruction
Results in a partial pressure of
carbon dioxide (PaCO2) of
greater than 60 mmHg
- Normal is 35-45 mmHg
Causes of hypercapnic failure?
Head trauma
Cervical spine disease
Lower motor neuron diseases
Laryngeal paralysis
Upper airway obstruction
Flail chest
How do you approach respiratory emergencies?
- Presentation
- Causes
- Cats vs dogs?
- Where is the problem?
- Upper or lower respiratory tract?
- Clinical signs for each?
What is the most important therapeutic drug for respiratory emergencies?
OXYGEN!!
Its widely available and relatively inexpensive!
What is FiO2?
Fraction of inspired oxygen
Room air:FiO2=21%
What is medical oxygen? (FiO2 %?)
100%
Can lead to oxygen toxicity so you dont want to leave patients on this oxygen for too long
May administer lower concentration depending on route utilized
Humidify if used for more than a few hours
Oxygen-routes of Administration
What is flow by oxygen?
- Provides 25%-40% oxygen
at a flow rate of 2-3 L/min - Well tolerated
- Can be used during initial
patient assessment
Oxygen-routes of Administration
Oxygen masks provide how much oxygen?
- Tight fitting face mask held to
patient’s face - Can provide FiO2 of 50-60% with high oxygen flow rates, 4-5 L/min
- Can be poorly tolerated
Oxygen-routes of Administration
What nasal oxygen?
- Unilateral or bilateral
- Easily placed
- 30%-70% FiO2
- 50-150ml/kg/min
- Per nasal oxygen line
Oxygen-routes of Administration
What would you set the oxygen flow rate for a 20kg dog with one nasal oxygen line?
- 0.5 L/min
- 2 L/min
- 5 L/min
- 10 L/min
Oxygen-routes of Administration
What are some other examples of oxygen routes of admin?
- Elizabethan collar
- Intratracheal oxygen
- Nasal cannula
- Oxygen cage
- Intubation
Why would you sedate an animal in respiratory distress?
Alleviates anxiety
Excellent for cases with upper airway distress
- Laryngeal paralysis
- Tracheal collapse
- Foreign body obstruction
May be used (with caution) with lower airway disease
- Pneumonia
- Pleural effusion
Types of sedation you can use for animals in respiratory distress? and routes of administration?
- Butorphanol
- Acepromazine –> use with caution in debilitated animals
Routes:
- IV
- IM
- SQ
You should always minimize stress in your respiratory distress patients by:
Minimizing handling
- May have to complete exam in
stages
- No major diagnostics until patient is “stable”
Ideally quiet room
- Especially cats
- Avoid distractions and noise
What is a thoracocentesis?
Process in which you remove fluid or air from the thoracic cavity
Performed to relieve:
- Pleural effusion
- Pneumothorax
- Also a diagnostic tool
Ideally performed before thoracic radiographs
Why would you intubate your patient?
- Ascertains patent airway
- Provides immediately control of
oxygenation and ventilation - Life saving!
- When to do it:
a. When it crosses your mind
b. Patient in overt respiratory distress - Tracheostomy may be needed in some cases!
What are some diagnostics that you will perform on your respiratory patients?
TFAST
Vet BLUE
Thoracic radiographs
Bloodwork
What is a TFAST?
Focused Assessment with Sonography for Trauma
- Assesses 2 sites on thorax:
a. CTS=chest tube site
b. PCS=pericardial site
What is Vet BLUE?
Another name and verson of a TFAST
Examines 4 sites:
- Cranial –> masses
- Middle –> aspiration pneumonia
- Perihilar –> heart disease
- Caudal –> non-cardiogenic edema, pulmonary edema
A-lines are
normal
B-lines are
Telling us there is extra fluid/edema in lungs
A glide sign is
the pleural surface rubbing against the thoracic wall
If there is no glide sign that means theres
pneumothorax
When should we take thoracic rads?
ALWAYS indicated in any animal with trauma
Even if they don’t have respiratory signs
- Diaphragmatic hernia
- Pneumothorax
Whats the minimum bloodwork in respiratory distressed pt? and whats advanced DX?
Minimum data base:
- PCV/total solids, blood glucose and lactate
Advanced diagnostics:
- CBC, Chemistry panel, electrolytes, urinalysis
What are other diagnostics that you can perform as indicated?
Bronchoscopy/Tracheoscopy
Thoracic CT
Abdominal radiographs
Abdominal ultrasound
Summary
Whats the exact approach to respiratory emergencies?
- Oxygen therapy
- Sedation (particularly for upper airway disease)
- Carry out physical exam in stages
- Thoracocentesis (if needed)
- Intubation (or tracheostomy) if needed
- Perform diagnostics
What are some specific respiratory emergencies?
Blunt and penetrating trauma
Based on anatomic location:
- Larynx and major extrathoracic airways
- Chest wall
- Pleural space
- Pulmonary parenchyma
The upper airways consist of
Nasal passages, choanae, naso/oropharynx,
larynx, trachea
Clinical signs associated with upper airway respiratory emergencies are?
Can be dynamic or static
- Stertor
- Stridor
- Coughing
- Gagging
- Nasal discharge
The general therapeutic guidelines to patient stabilization of upper airway emergencies include:
Provide oxygen
Provide sedation
Prepare to intubate
May require tracheostomy tube