A guide for assessing respiratory emergencies

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Knowing how to accurately conduct focused respiratory assessments is crucial during respiratory emergencies. In her session, “Triaging the Respiratory Emergency,” presented at the 2024 New York Vet Show in New York, New York, Mariana Pardo, BVSc, MV, DACVECC, lectured attendees on how to recognize the different breathing patterns and respiratory sounds that patients in respiratory distress may display, and what these may indicate.¹ She also provided an overview on lung and cardiac auscultation, teaching attendees how to identify determine whether or not there may be cardiac disease present in feline and canine patients. 

Breathing patterns

At the beginning of her lecture, Pardo outlined different breathing patterns that veterinarians should recognize and explained that patients with a normal breathing patten have a chest that rises with inspiration. If there is a long inspiration and exhalation however, it may mean that there is a constant airway obstruction. Patients exhibiting a long inspiration but normal exhalation, likely have laryngeal paralysis, or a dynamic obstruction. Meanwhile, a long, forceful exhalation with or without cough is indicative of intrathoracic airway collapse or obstruction. There is a concern for pleural space disease is rapid, shallow breathing is observed. Lastly, paradoxical breathing is when the chest falls on inspiration and the abdomen expands, or belly breathing is observed, Pardo explained.

Respiratory sounds

Respiratory sounds consist of stridor, stertor, and noisy breathing.

• Stridor: A high-pitched sound due to rigid tissue vibrations. A collapsing trachea will have that high-pitched sound. “Sometimes we can hear it from the lobby that it’s happening,” explained Pardo.
• Stertor: A low-pitched sound resulting from flaccid tissue vibrating throughout the respiratory cycle. “We all have heard that Bulldog, low-pitch sound that's associated with that fatty tissue,” said Pardo.

A “noisy breathing effort and in general…wet panting, is all going to give you clues of potentially what is occurring,” added Pardo.

Lung Auscultation

When auscultating lungs, it is imperative that the practitioner use a stethoscope to listen to the patient’s entire lung, including the dorsal and ventral aspects of the chest, explained Pardo. “Sometimes we just listen to one spot, and then we're done, [but] the entire lung is much bigger than that,” she said.

Veterinarians should also pay attention to the quality of the sound, said Pardo. “So, is [the sound] stronger or not in one or more areas? [Are] there any wheezing, crackles? And specifically, is there a decreased or absent sounds all together?” she emphasized.

Wheezing is generally linked to narrowed airways (stenosis), typically due to inflammation in the airways. Additionally, decreased or absent lung sounds can be caused by:

• Fluid in the lungs
• Tissue obstructing the pathway to listen to the lungs or tissue within the lungs
• Obstruction due to other material, such as blood or air, that may be present between the thoracic wall and the lung.

“You can also hear when there is really severe lung consolidation, so there’s just no air flow within that lung itself,” said Pardo. In cases of severe consolidation or lung disease, crackles may initially be heard, but as the condition worsens, lung sounds may completely disappear.

As part of her lecture, Pardo then showed attendees a table with various diseases and what their breathing patterns may be¹:

• Upper airway obstruction: inspiratory dyspnea and/or audible noises (stertor, stridor).
  • Examples: brachycephalic airway disease, Laryngeal paralysis, or tracheal collapse
• Lower airway obstruction: expiratory dyspnea, and/or wheezes.
  • Example: asthma
• Pulmonary Parenchymal disease: rapid and/or shallow breathing, inspiratory and expiratory components.
  • Examples: pneumonia, interstitial lung disease, pulmonary edema, or pulmonary contusions
• Pleural space disease: inspiratory dyspnea, shallow or paradoxical breathing, or decreased or absent lung sounds.
  • Examples: pneumothorax or pleural effusion
• Flail chest: focal paradoxical breathing.
  • Example: rib fractures
• Abdominal distention: inspiratory dyspnea.
  • Example: ascites or organomegaly
• Look-alike disease: no specific breathing pattern.
  • Examples: pain, severe anemia, hyperthermia, acidosis, or drugs like opioids

Cardiac auscultation and potential heart disease

Cardiac auscultations are important for determining if there is cardiac disease instead of respiratory disease, said Pardo during her lecture.

Dogs

Pardo explained that the majority of dogs with congestive heart failure will have an audible heart murmur. “The caveat to that is that sometimes your lung cells are so bad when you have congestive heart failure that you may not just be able to hear your heart at all, and just not be able to know [if] there [is] a murmur present, [nor] be able to grade that, because all you hear are just white sounds,” she said. “But that doesn't mean there's not a murmur—you just can't assess the heart altogether.”

Cats

In cats however, the same does not apply. Only 50% of cats with heart disease will have a heart murmur, according to Pardo. “The other 50% will still have really, really bad heart disease, might still go into congestive heart failure, and have never had a heart murmur at all,” emphasized Pardo.

Instead, these felines will likely exhibit gallop sounds. “80% of cats [with heart disease] will have a gallop [heart sound]... so make sure you're still looking out for that as well,” said Pardo. Still, she explained that there are cats that will not have any abnormal heart sounds but will still have heart disease.

Conclusion

Recognizing various breathing patterns and respiratory sounds is essential for veterinarians diagnosing and managing respiratory and cardiac conditions in animals. As highlighted by Pardo, thorough lung auscultation and an understanding of the relationship between specific sounds and potential health issues can significantly improve patient outcomes. Additionally, integrating these assessments into practice can help veterinarians be able to better distinguish between respiratory and cardiac diseases.

Reference

1. Pardo M. Triaging the Respiratory Emergency. Presented at: 2024 New York Vet Show; November 7- 8, 2024; New York, NY.