Respiratory Distress Flashcards
What are the 5 basic mechanisms by which hypoxemia can occur?
Decreased FiO2, hypoventilation, diffusion barriers, anatomic shunting, and ventilation/perfusion (V/Q) mismatch
How do you determine that hypoxemia is due to decreased FiO2?
Generally due to a complication of anesthesia or assisted ventilation
How do you determine that hypoxemia is due to hypoventilation?
Can use the Alveolar-arterial (A-a) gradient; will typically have concurrent hypercapnia
How do you determine that hypoxemia is due to diffusion abnormalities?
Diffusion abnormalities rarely are the sole cause of clinically significant hypoxemia, they often exacerbate other problems
How do you determine that hypoxemia is due to an anatomic shunt?
Typically these are congenital disorders
Describe how hypoxemia can occur due to a V/Q mismatch
Can occur if there are regions in the lung of high (reduced perfusion) or low (reduced ventilation) V/Q; the ventilation and perfusion of all regions of the lungs must be appropriately matched for all blood leaving the lungs to be fully oxygenated
Extrathoracic airway obstruction most commonly leads to ________ distress in addition to a prolonged ______________ phase
Inspiratory; inspiratory (e.g. cervical tracheal collapse and lar par)
Intrathoracic airway obstruction most commonly leads to ________ distress in addition to a prolonged ______________ phase
Expiratory; expiratory (e.g. intrathoracic tracheal collapse, chronic bronchitis)
True respiratory distress implies what?
Involvement at or below the level of the oropharynx (cats can be the exception)
Late-inspiratory crackles can be auscultated in patients that have what?
Pulmonary edema, lung, pleural or chest wall tumors, or interstitial pneumonia
Early inspiratory or expiratory crackles may be heard with what?
Obstructive lung disease, bronchopneumonia, or conditions resulting in tracheobronchial fluid
Inspiratory wheezes are associated with what?
Extrathoracic airway obstruction (e.g. masses, stenosis, or collapse of upper airways or extrathoracic trachea)
Late inspiratory wheezes may be auscultated with what conditions?
Atelectasis or consolidation of lung lobes (need to localize at site of max intensity)
Expiratory wheezes are associated with what?
Intrathoracic airway obstructions (COPD, intrathoracic airway collapse, stenosis, or mass obstruction)
When might you hear a fluid line?
In patients with pleural effusion (ventral) or pneumothorax (dorsal)
What should you be prepared to when while giving a patient in respiratory distress an oropharyngeal exam?
Incubate - typically these are done under minimal sedation, but animal may become stressed
What would seeing normal appearing lung fields on thoracic radiographs of a patient in respiratory distress suggest?
A defect in oxygen transport or perfusion of lungs/tissue
PaO2 and PaCO2 in ____ specimens provide useful info about pulmonary function
Arterial; venous blood is less useful b/c affected by cardiac function and peripheral circulation
What are arterial blood gas measurements indicated to document?
Pulmonary failure, to differentiate pulm dz from hypoventilation, to determine the need for intervention, and to monitor response to therapy; respiratory compromise must be SEVERE for abnormalities to be detectable
What parameter should always be measured at the same time as taking an arterial sample?
Body temp
If the PaO2 is very low and they PaCO2 is low, normal, or mildly elevated, and the dog is breathing relatively normally, what type of sample do you probably have?
Venous or mixed
A PaO2 of less than ___ mmHg is considered dangerous and treatment should be initiated urgently
60
A PaO2 of less than 50 mmHg and/or a PaCO2 of greater than 50 mmHg in the face of O2 therapy generally indicates what?
Current or impending pulmonary failure and patients often need assisted ventilation
T or F: Cyanosis develops more quickly in animals with polycythemia than anemia
True; cyanosis is a result of the increased concentration of non-oxygenated Hb in the blood.
Which two values are commonly used to make rough assessments of pulmonary function and to monitor the course of disease or response to treatment?
A-a gradient and FIO2:PaO2
Pulse oximetry measures what value?
Oxygen saturation (SpO2)
T or F: A normal value on a Pulse Ox does not rule out hypoxia.
True; could have anemia, CO poisoning, cyanide toxicity
An 8 year old Lab presents to you in respiratory distress. You note stridor, and his tongue is purple upon physical exam. The owner mentioned his bark has changed over the past 2 months, and he has been having periodic episodes of ‘collapse’ and exercise intolerance. What’s your primary differential?
Lar par
What diagnostic test must be performed to confirm a lar par diagnosis?
Laryngoscopy
What are the abnormalities associated with brachycephalic syndrome?
Stenotic nares, hypoplastic trachea, everted laryngeal saccules and laryngeal collapse, elongated soft palate
Early routine surgical correction of which two known brachycephalic syndrome-associated abnormalities can potentially prevent eversion of laryngeal saccules and laryngeal collapse?
Elongated soft palate and stenotic nares
Name a few primary disease processes associated with PTE
Cushing’s, hypothyroidism, PLN, IMHA, cardiac dz, HWD, sepsis, DIC, pancreatitis, neoplasia
What is the clinical presentation of feline asthma?
Typically young adult to middle aged cat with progressively worsening sudden episodes of labored breathing, and increased expiratory effort/time, expiratory wheezes, +/ crackles
What is the only condition causing respiratory distress where bronchodilators are indicated?
Feline asthma
What medications should you always give with some type of anti-inflammatory?
Bronchodilators
