Thoracic Point-of-Care Ultrasound in Respiratory Patients

Keynote Message

• Point-of-care ultrasound (POCUS) has revolutionized the way triage and initial therapy are performed in human and veterinary patients. POCUS can give rapid information about cardiovascular and respiratory compromise. Thoracic ultrasound can offer information about air or fluid accumulation in the thoracic or pericardial space, volume status, cardiac function or congestion, and fluid responsiveness. POCUS allows for rapid guidance of procedures, reducing risk, and tracking the evolution of the patient.


• POCUS ought to be question driven, with clinical questions being directed by signalment, presenting complaint, and additional triage information gathered during the shortened history and primary survey of the patient. The questions are typically closed questions, with a limited number of possible answers, often binary in nature.


• POCUS of the pleural space allows for rapid rule in or rule out of pleural effusion or a pneumothorax. Recognizing the BAT sign and glide sign with the probe held perpendicular to the ribs is the first step to performing pleural and lung ultrasound. Knowledge of the sonoanatomic boundaries of the thoracic cavity will improve the sensitivity and specificity of these tests, allowing us to assess the places where fluid and air are supposed to accumulate. The pleural and lung ultrasound protocol that the operator applies will hence impact the results.


• Clinically significant pulmonary parenchymal disease will cause B-lines and consolidations in most patients. Similarly to pleural space diseases, the protocol used will impact the likelihood of identifying lesions, as their distribution depends on the type of pathology.


• Cardiovascular POCUS allows rapid assessment of emergency conditions such as pericardial effusion and tamponade, as well as cardiac dysfunction and volume status. Pericardial tamponade can be easily identified through different windows, and should be differentiated from pleural effusion.


• Left-sided congestive heart disease, as well as right-sided changes compatible with pulmonary hypertension, can be readily observed by a trained clinician. Cardiac filling and caudal vena cava assessment can further help to guide initial resuscitation of emergency patients, by providing information about the volume status of the patient.


• Although POCUS has the potential to more efficiently care for our emergency patients, its success depends on the clinician being able to formulate the correct questions she/he wants to answer, as well as the same clinician being able to correctly define the skillset she/he masters. Fishing expeditions, as well as overinterpretation of findings, are some of the biggest risks for the implementation of POCUS in practice. A practice protocol or guideline providing a clear framework (e.g., recording of images, reporting of findings, feedback on cineloops) for all clinicians to perform POCUS whilst recognizing these pitfalls may avoid such issues.

Key References

1.  Boysen S, Gommeren K, Chalhoub S. The Essentials of Veterinary Point of Care Ultrasound: Pleural Space and Lung. Grupo Asís Biomedia SL; 2022.

2.  Fernandes Rodrigues N, Giraud L, Bolen G, Fastrès A, Clercx C, Boysen S, Billen F, Gommeren K. Comparison of lung ultrasound, chest radiographs, C-reactive protein, and clinical findings in dogs treated for aspiration pneumonia. J Vet Intern Med. 2022;36(2):743–752. doi: 10.1111/jvim.16379. Epub 2022 Mar 5. PMID: 35247005. https://pubmed.ncbi.nlm.nih.gov/35247005.

3.  Fernandes Rodrigues N, Giraud L, Bolen G, Fastrès A, Clercx C, Gommeren K, Billen F. Antimicrobial discontinuation in dogs with acute aspiration pneumonia based on clinical improvement and normalization of C-reactive protein concentration. J Vet Intern Med. 2022;36(3):1082–1088. doi: 10.1111/jvim.16405. Epub 2022 Mar 29. PMID: 35348224. https://pubmed.ncbi.nlm.nih.gov/35348224.

4.  Boysen S, McMurray J, Gommeren K. Abnormal curtain signs identified with a novel lung ultrasound protocol in six dogs with pneumothorax. Front Vet Sci. 2019;6:291. doi: 10.3389/fvets.2019.00291. eCollection 2019. PMID: 31555674. https://pubmed.ncbi.nlm.nih.gov/31555674.

5.  Lyssens A, Lekane M, Gommeren K, Merveille AC. Focused cardiac ultrasound to detect pre-capillary pulmonary hypertension. Front Vet Sci. 2022;9:830275. doi: 10.3389/fvets.2022.830275. eCollection 2022. PMID: 35300218.

6.  Darnis E, Merveille AC, Desquilbet L, Boysen S, Gommeren K. Interobserver agreement between non-cardiologist veterinarians and a cardiologist after a 6-hour training course for echographic evaluation of basic echocardiographic parameters and caudal vena cava diameter in 15 healthy beagles. J Vet Emerg Crit Care (San Antonio). 2019;29(5):495–504. doi: 10.1111/vec.12883. Epub 2019 Aug 27. PMID: 31453666.