SA Respiratory Emergencies Flashcards
1
Q
Respiratory distress is considered
A
Physically labored respiration
2
Q
Define dyspnea
A
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”
3
Q
How can one identify respiratory distress?
A
Increased respiratory rate
Increased respiratory effort
Orthopnea –> elbows out
Open mouth breathing –> not panting tho
Cyanosis
Stridor
Occasionally signs may not be as obviously
4
Q
T/F Respiratory distress is considered a Common cause of presentation to ER.
A
True
5
Q
Respiratory distress is..
A
Life threatening and causes patient and owner distress
6
Q
What are some physiologic dysfunctions that result when respiratory distress occurs?
A
- Hypoxemic
respiratory failure –> not getting enough O2 in circ - Hypercapnic
respiratory failure –> not getting rid of CO2
7
Q
What is hypoxemia?
A
- Partial pressure of oxygen in blood (PaO2) of less than
<80mmHg - SpO2 (percent oxygen saturation) <95%
8
Q
What is normal PaO2 and SpO2?
A
Normal PaO2 is 80-100mmHg, normal SpO2>95%
9
Q
Life threatening (severe) hypoxemia is:
A
PaO2<60mmHg, SpO2<90%
10
Q
How do you measure PaO2 and SpO2?
A
PaO2–> measured by arterial blood gas
SpO2 –> measured by pulse
oximetry
SaO2 –> measured by arterial
blood gas
11
Q
What 2 forms is oxygen dissolved in?
A
- Dissolved in blood (PaO2)
- Carried by hemoglobin (SpO2 or SaO2)
90 SpO2 correlates to 60 PaO2 –> not great
12
Q
Under GA and intubation your PaO2 is what? and your spO2 is what?
A
PaO2 is 500 and spO2 is 100%
13
Q
What is Pulse Oximetry used for?
A
- Differential absorption of infrared light by oxygenated and deoxygenated Hb
- 2 wavelengths of light (red and
infrared) used - Oxygenated Hb absorbs more infrared light
14
Q
What are the two types of pulse ox available?
A
Transmissive probe
Reflectance probe
15
Q
Describe the transmissive probe
A
- Most commonly used
- Sites: lip, tongue, pinna, toe webbing, prepuce, vulva
- Can be challenging in awake
patients
16
Q
Describe the reflectance probe.
A
- Often better tolerated
- Must be used over a bony surface
- EX: Tail base, rib, metacarpal area, metatarsal
area
17
Q
What are some limitations of pulse oximeters?
A
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
18
Q
In order for pulse oximeters to work they must be:
A
- Over an area of pulsatile blood flow
- Patients heart rate must match pulse oximeter reading
19
Q
What is arterial blood gas?
A
- 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
20
Q
What is cyanosis?
A
- 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!
21
Q
What are causes of hypoxemic respiratory failure?
A
Pneumothorax
hemothorax
pleural effusion
pneumonia
pulmonary edema
pulmonary contusion
pulmonary thromboembolism
22
Q
What is hypercapnic respiratory failure?
A
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
23
Q
Causes of hypercapnic failure?
A
Head trauma
Cervical spine disease
Lower motor neuron diseases
Laryngeal paralysis
Upper airway obstruction
Flail chest
24
Q
How do you approach respiratory emergencies?
A
- Presentation
- Causes
- Cats vs dogs?
- Where is the problem?
- Upper or lower respiratory tract?
- Clinical signs for each?
25
What is the most important therapeutic drug for respiratory emergencies?
OXYGEN!!
Its widely available and relatively inexpensive!
26
What is FiO2?
Fraction of inspired oxygen
Room air:FiO2=21%
27
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
28
# 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
29
# 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
30
# Oxygen-routes of Administration
What nasal oxygen?
- Unilateral or bilateral
- Easily placed
- 30%-70% FiO2
- 50-150ml/kg/min
- Per nasal oxygen line
31
# 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
32
# Oxygen-routes of Administration
What are some other examples of oxygen routes of admin?
- Elizabethan collar
- Intratracheal oxygen
- Nasal cannula
- Oxygen cage
- Intubation
33
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
34
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
35
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
36
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
37
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!
38
What are some diagnostics that you will perform on your respiratory patients?
TFAST
Vet BLUE
Thoracic radiographs
Bloodwork
39
What is a TFAST?
Focused Assessment with Sonography for Trauma
- Assesses 2 sites on thorax:
a. CTS=chest tube site
b. PCS=pericardial site
40
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
41
A-lines are
normal
42
B-lines are
Telling us there is extra fluid/edema in lungs
43
A glide sign is
the pleural surface rubbing against the thoracic wall
44
If there is no glide sign that means theres
pneumothorax
45
When should we take thoracic rads?
ALWAYS indicated in any animal with trauma
Even if they don’t have respiratory signs
- Diaphragmatic hernia
- Pneumothorax
46
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
47
What are other diagnostics that you can perform as indicated?
Bronchoscopy/Tracheoscopy
Thoracic CT
Abdominal radiographs
Abdominal ultrasound
48
# Summary
Whats the exact approach to respiratory emergencies?
1. Oxygen therapy
2. Sedation (particularly for upper airway disease)
3. Carry out physical exam in stages
4. Thoracocentesis (if needed)
5. Intubation (or tracheostomy) if needed
6. Perform diagnostics
49
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
50
The upper airways consist of
Nasal passages, choanae, naso/oropharynx,
larynx, trachea
51
Clinical signs associated with upper airway respiratory emergencies are?
Can be dynamic or static
- Stertor
- Stridor
- Coughing
- Gagging
- Nasal discharge
52
The general therapeutic guidelines to patient stabilization of upper airway emergencies include:
Provide oxygen
Provide sedation
Prepare to intubate
May require tracheostomy tube
53
Injuries of the upper airways are usually caused by:
Bite wounds
Blunt trauma
Gunshot wounds
54
Tracheal lacerations are generally associated with?
orotracheal intubations especially in cats
But can be see in dogs and cats with:
- Bite wounds
- Vehicular accidents
- High rise falls
- Projectile wounds
55
How do you diagnose tracheal lacerations?
Physical exam
- Rarely reveals obvious laceration
Thoracic radiographs
- Pneumomediastinum
- Pneumothorax
- Pneumoretroperitoneum
- Subcutaneous emphysema
Tracheoscopy
- May not identify small tears
Surgical exploration
- Usually reserved for worsening
or unresponsive cases
Okay to have a strong index of
suspicion
56
How do you treat tracheal lacerations?
Oxygen therapy
Sedation
Cage rest
Removal of subcutaneous air
- Not routinely performed
Surgery
- Pneumothorax worsens or does not resolve
- Thoracostomy tubes may be used for management of
continued pneumothorax
57
Laryngeal hematoma/edema is an upper airway injury caused by?
- Bite wounds
- Blunt trauma
- Rodenticide toxicity/coagulopathy
- Snake bite
- Hypoalbuminemia
- Parasites (Cuterebra)
- Neoplasia
## Footnote
Bite wounds and rodenticide most common
58
What are the clinical signs of Laryngeal hematoma/edema?
Respiratory distress
Generally present with stridor
- Inspiratory effort
Watch out for other organ systems potentially affected by trauma
59
How do you diagnose laryngeal hematomas/edema?
- Physical exam
- Sedated oral exam
- Cervical radiographs
- Computated tomography
60
How do you treat laryngeal hematomas/edema?
- Sedation
- Oxygen therapy
- Cage rest
- Antibiotics (bite wounds)
- Tracheostomy may be needed
- Surgical exploration rarely indicated
61
Bite wounds can manifest in the?
- Oral cavity
- Larynx
- Pharynx
- Trachea
62
What are the physical exam findings and DX you will have in bite wound patients?
- Respiratory distress
- Hemorrhage
- Oral fractures
- Other signs associated with trauma
Ensure patient is stable before focusing on wounds
63
How do you approach a bite wound patient?
1. Sedation
a. opioids
b. opioids and benzos
c. GA may be required
2. Shave and clean wounds
3. Evaluate to determine extent
4. May close or leave to close by secondary intention
64
How do you treat bite wounds?
Antibiotic Therapy
- Broad spectrum to cover gram positive and negative bacteria:
Ampicillin, Potentiated ampicillin, Cephalosporins
Discharge with 5-10 days worth of antibiotics
- Depending on severity of injury
65
Injuries to the chest wall results in?
- Rib fractures
- Pneumothorax
- Hemothorax
- Flail chest
66
Rib fractures are associated with
- Blunt force trauma
- Bite wounds
67
What would you find on your PE with a rib fracture patient?
- Pain associated with palpation of thoracic wall
- Respiratory distress
- Clinical signs may be minimal --> ex: rib fractures with no lung pathology
- Remember to look for other signs associated with trauma
68
How do you DX rib fractures?
PE
Thoracic rads
69
How do you manage rib fractures?
- Most treated conservatively
- Pain management
- Cage rest
- Surgical intervention rarely needed ---> Unless theyre lacerating a lung lobe!
- Intercostal blocks help!!
70
What is flail chest?
Part of the thoracic body wall becomes “unattached” from the rest of the chest wall
- Segmental fracture of two or more adjacent ribs
Causes paradoxical movement of the unstable segment during respiration
When you expand chest the segement fractured sucks in
71
In flail chest on inspiration there is negative force generated and the flail segment will...
collapse inward
72
In flail chest on expiration there is positive force generated and the flail segment will...
flail out
73
What is a cause of flail chest?
Almost always associated with blunt force injury
74
What are your PE findings of flail chest?
- Respiratory distress
- Obvious flail segment visualized on physical exam
- Looks for other signs associated with trauma
75
Flail chest can lead to pain and hemorrhage which can cause?
Pain
- Leads to decreased ventilation and ultimately hypoxemia
and hypercapnea
Hemorrhage
- Significant life threatening hemorrhage may occur as a
result of displaced ribs
76
How do you DX flail chest?
Physical exam
Radiographs confirm but rarely needed to make diagnosis
- Important for evaluation of other complications of trauma usually associated with flail chest
77
What are some other complications of flail chest?
Pneumothorax
Hemothorax
Pulmonary contusions
Subcutaneous emphysema
78
How do you manage pain of Flail chest?
Opioids are mainstay of therapy. Minimal cardiorespiratory depression at appropriate doses
- Fentanyl
- Hydromorphone (causes panting)
- Morphine (may cause histamine release)
- Buprenorphine (not great for moderate to severe
pain)
- Butorphanol is inappropriate. Minimal analgesia provided
Local nerve blocks also work great
- 2 rib spaces cranial and caudal to flail section
## Footnote
Hydro can make them even more painful if theyre breathing hard
79
Other therapeutic methods for flail chest?
Minimize motion of flail section
- Light wrap may be considered
- Place animal in lateral recumbency with flail side down
80
Is surgery an option for flail chest patients?
Reserved for patients with moderate to severe displacement of flail section
81
Do we need to mechanically ventilate our flail chest patients?
We can, depends on how severe they are
82
Open chest wounds are
Challenging but relatively uncommon
83
What will you find on your PE in open chest wound PTs?
- Open thoracic wound. Sucking sound appreciated as
patient ventilates
- Lungs may be visualized
- Respiratory distress
- Look for other signs associated with trauma
84
How do you DX open chest wounds?
Physical exam is generally sufficient to make diagnosis
Thoracic radiographs when animal is stable
- Rib fractures
- Pulmonary parenchymal injuries (contusions)
- Pneumothorax
- Diaphragmatic hernia
Other diagnostics as indicated
- CBC, Chemistry, UA
- Abdominal imaging
85
When should you do surgical exploration in open chest wound patients? and why?
- once animal is stable
- Determine extent of wound
- Lavage thoracic cavity
- Place thoracostomy tube in cases of continuous pneumothorax
86
What are some pleural space injuries?
Pneumothorax
Hemothorax
Diaphragmatic hernia
Gun shot injuries/penetratiing trauma
87
What are some traumatic causes of pneumothorax?
Blunt force injuries
- Vehicular trauma
- Ran into object
Projectile injuries
88
What are some non-traumatic causes of pneumothorax?
- Pulmonary bullae
- Pneumonia
- Iatrogenic causes
89
Pneumothorax is caused by
- Alveolar rupture due to increased transthoracic force
- Laceration of the pulmonary parenchyma
90
Pneumothorax can be classified as:
Open or closed (most common form)
## Footnote
Open is seen with open thoracic injuries and open chest injuries
91
What is tension pneumothorax?
- One way valve created in thorax where you have a defect in wall
- Increased intrapleural pressure
a. Decreased venous return
b. Cardiovascular collapse
92
In tension pneumothorax on inspiration:
air leaves lung, goes into thoracic cavity and comes through one way valve in tissue
93
In tension pneumothorax on expiration:
One way valve closes and basically seals over --> this results in continuous building of pressure or air
94
What are the physical exam findings in a dog with a pneumothorax?
Respiratory distress
Tachypnea
Cyanosis
Quiet lung sounds dorsally
Hyper-resonance on
percussion of dorsal
aspect of thorax
95
When you perform a thoracocentesis you go between which rib spaces?
Numbers 7-9
96
In thoracocentesis to remove air go..?
To remove fluid go..?
Air--> dorsal
Fluid-->ventral
97
What are some indications for thoracostomy tubes?
Open pneumothorax
Closed pneumothorax
- Continuous production of air
- Needs frequent thoracocentesis
98
A hemothorax will occur as a result of injury to:
Chest wall
Lung parenchyma
Great vessels
- Animals with great vessels injuries do not survive long
99
Animals can also develop hemothorax if they ingest?
Anticoagulant Rodenticides
100
Hemothorax results in the accumulation of how much fluid?
30-60 ml/kg of fluid
May not be clinical until large volumes
accumulate
101
How do you DX hemothorax?
Thoracic radiographs/Thoracic Ultrasound
- Only confirms presence of pleural effusion
Thoracocentesis
- Presence of non clotting blood confirms diagnosis
- Check PCV/TS of fluid in the thoracic cavity --> compare this to periphery and if theure actively bleeding then PCV will be same in chest as in periphery
102
What are some therapeutic options for animals with hemothorax?
Thoracocentesis
- Consider autotransfusion
Fluid therapy
Analgesia
Surgical exploration may be required
- Rarely indicated unless large amount of bleeding in patient that cannot be stabilized
103
Diaphragmatic hernias are associated with?
Most commonly associated with trauma
- 85% in one study
Many more concurrent injuries usually present
- Mostly caudal to the thorax
104
What organs are going to be herniated in a diaphragmatic hernia?
Liver (most common)
Small intestine
Stomach
Spleen
Omentum
105
Most injuries in diaphragmatic hernias are right sided. Why?
Stomach “protects” the left side
106
What are the clinical signs of diaphragmatic hernias?
- May not show any respiratory signs
- Tachypnea
- Respiratory distress
- Quiet lung sounds ventrally
- Borborygmi on thoracic auscultation --> gi sounds
- Cardiovascular and respiratory collapse
a. If gastric dilation is present --> due to inhalation of a ton of air
107
How do you DX diaphragmatic hernias?
Thoracic radiographs
- Gold standard
Rarely
- Abdominal ultrasound
- Positive contrast peritoneography
- Positive contrast gastrography
108
How do you treat diaphragmatic hernias?
Surgical repair when animal is
stable
Debate over ideal timing of
surgery
- Wait 24 hours vs. as soon as
patient is stable
109
Emergency SX is indicated in diaphragmatic hernias when?
- Stomach is in thorax
- Strangulated viscera
- Patient cannot be stabilized
110
What is the most common projectile injury in SA?
Gunshot wounds
111
Gunshot wounds cause injury to:
Lungs (somewhat resilient)
Great vessels
Ribs
112
How do gunshot wound dogs/cats present?
Respiratory signs
- Hemothorax
- Pneumothorax
Cardiovascular signs
- Shock (due to significant blood loss)
- If tension pneumothorax present
Look for other signs of trauma
- Abdominal wounds
- Fractures
113
How do you DX gunshot wound pts?
History
Physical exam
Thoracic radiographs (once animal is stable)
Abdominal imaging
114
What are some therapeutic options for gunshot wound patients?
Thoracocentesis
- Pneumothorax
- Hemothorax
Fluid therapy
- May require blood transfusion
Thoracostomy tube
Exploratory surgery in some cases
- Thoracotomy
- Abdominal exploratory
115
What are the diseases of the pulmonary parenchyma?
Pulmonary contusions (very common)
Lung lacerations
Pulmonary hematomas
Intrabronchial hemorrhage
116
Pulmonary contusions rarely exist as...
an isolated injury --> look for other things
Very common after blunt force trauma
117
Pulmonary contusions consist of:
- Pulmonary interstitial hemorrhage
- Alveolar hemorrhage and edema
they look like consolidated areas of lung pneumothorax and pulmonary contusions
118
Pulmonary contusions lead to:
- Increase in lung water
- Decreased lung compliance
- V/Q mismatch
119
On radiographs pulmonary contusions can be:
throughout whole thorac or unilateral it just depends on the trauma
120
How long will it take for pulmonary contusions to resolve?
3-7 days
It can get acutely worse within 24-72 hours
121
What are some complications of pulmonary contusions?
- Secondary bacterial pneumonia
- Acute Respiratory Distress Syndrome (ARDS)
122
What will you find on your PE on an animal with pulmonary contusions?
- Tachypnea
- Respiratory distress
- Harsh lung sounds
- Crackles
123
What are the therapeutic options for an animal with pulmonary contusions?
Usually supportive
- Oxygen
- Cage rest
- Judicious use of intravenous
fluids --> overhydration can lead to vascular leakage which can worsen pulmonary contusions
- Mechanical ventilation
No evidence supporting use of
- Corticosteroids
- Antibiotics
124
What is mechanical ventilation?
Positive pressure ventilation --> pushes air in
## Footnote
We normally have negative pressure
125
What are some indications for mechanical ventilation?
- PaO2 <60mmHg (on arterial blood gas)
- PaCO2 >60mmHg
- Increased work of breathing
126
Common conditions that require mechanical ventilation?
Pneumonia
ARDS
Congestive heart failure
Neurologic conditions (cervical spinal injuries, lower
motor neuron disease)
Toxicities
127
A mechanical ventilator can program:
- FiO2 (21%-100%)
* Tidal volume
* Respiratory rate
* Inspiratory pressure
* Inspiratory time
* PEEP
* And more!!
128
What is PEEP?
Positive end-expiratory pressure
If you take a big breath and only exhale part of it, what is left is PEEP
PEEP helps alveoli from collapsing when lungs are completely empty
129
A surgical ventilator can program:
- FiO2 100% only
* Tidal volume
* Respiratory rate
130
Mechanical ventilators are considered:
- NOT benign but can be life saving
- Fastidious patient care essential
- Can create serious complications
- VAP-ventilator associated pneumonia
- VILI-ventilator associated lung injury
a. Stretch injury
b. Shear injury
c. Biotrauma
- AKI-decreased venous return from abdomen --> decreased renal blood flow/GFR (because increase in press. from thorax thats not normal)
131
When you use a mechanical ventilator prognosis is?
- Guarded to poor
- Neurologic disease/toxin ingestion carries a
better prognosis than primary pulmonary
pathology
132
What is High flow oxygen therapy?
- Delivers humidified/heated oxygen
- FiO2 programmable from 21%-100%
- Volume delivered ranges from 2-60L/min
- Generally well tolerated
- No need for heavy sedation/anesthesia
- Can be used in patients that fail traditional oxygen therapy (cages/nasal cannulas)
- May prevent the need for mechanical ventilation
