Veterinary point-of-care ultrasound probe orientation and location for detection of pleural effusion in canine cadavers: a pilot study.

Abstract

Objectives: To evaluate whether point-of-care ultrasound probe location (at or below the costochondral junction) and probe orientation (perpendicular or parallel to the ribs) affect operator ability to detect pleural effusion in a canine cadaver model.

Materials and methods: Twelve intubated canine cadavers with scant to large volume pleural effusion were scanned in sternal recumbency while receiving positive pressure ventilation. Twelve operators (2 emergency and critical care specialists, 2 veterinary students and 8 interns) performed blinded bilateral thoracic point-of-care ultrasound using two randomised scanning protocols: a modified TFAST for pleural fluid technique and a modified Calgary PLUS for pleural fluid technique. Hemithoraces were categorised as scant-to-mild or moderate-to-large effusion for statistical analysis. Paired detection rates were compared using McNemar's test.

Results: Overall detection of pleural effusion was significantly higher using the modified Calgary PLUS for pleural fluid technique compared with the modified TFAST for pleural fluid technique (89.1% vs. 60.9%; P < .001). There was a statistically significant increase in the detection of scant-to-mild effusion with the modified Calgary PLUS for pleural fluid technique (84.4% vs. 37.5%; P < .001). No significant difference was observed for moderate-to-large effusions (93.8% vs. 84.4%; P = .25).

Clinical significance: The site assessed and probe orientation used with different thoracic point-of-care ultrasound protocols can influence the operator's ability to detect pleural effusion in positive pressure ventilation canine cadavers placed in sternal recumbency. Incorporating a probe orientation that is parallel to the ribs in the more ventral regions of the thorax during point-of-care ultrasound may improve the operator's detection of pleural effusions, particularly when smaller volumes of pleural fluid are present.