Vertical displacement of pleura: a new method for bronchospasm evaluation?

Abstract

Background: Lung ultrasonography has been increasingly recognized has a valuable diagnostic tool. In adult patients with asthma/chronic obstructive pulmonary disease and wheezing, LUS usually presents as an A/nude profile (normal profile, with sliding and A-lines, and without any abnormal findings) or at most reveals a decrease/absence of lung sliding. Therefore, until now simple point-of-care ultrasonography appeared to be unable to assess the severity of airflow limitation.

Case presentation: We report the case of a woman presenting to the emergency department with an asthma exacerbation. Bedside ultrasound showed the usual A/normal profile, but also an associated vertical pleural displacement, probably secondary to hyperinflation and accessory muscle recruitment. We evaluated the described movement with M-mode and established a comparison index between end-inspiration and end-expiration, using the skin as reference. This index showed improvement and complete normalization during treatment.

Conclusions: Pleural vertical displacement appears to be a sonographic alteration associated to bronchospasm and accessory muscle recruitment. It is easily identifiable and measurable on LUS, thus possibly representing a new method to evaluate bronchospasm and monitoring treatment response. Further research is needed to confirm or refute this finding.

Keywords: Asthma/COPD; Bronchospasm; Diagnostic imaging; Emergency medicine; Lung ultrasonography; Point-of-care ultrasonography.

Fig. 1

M-mode evaluation of pleural vertical displacement and calculus of the comparison index: $\frac{\text{Skin-to-maximal inspiration point distance}\left(\text{A}\right)-\text{skin-to-maximal expiration point distance}\left(\text{B}\right)}{\text{skin-to-maximal inspiration point distance}\left(\text{A}\right)}\times 100$

Fig. 2

M-mode re-evaluation of the pleural displacement and index calculation at 17 min of treatment, showing improvement with treatment

Fig. 3

M-mode re-evaluation of the pleural displacement and index calculation at 21 min of treatment, showing complete resolution of pleural displacement an index normalization