Measuring changes in chest wall motion after lung resection using structured light plethysmography: a feasibility study

Objectives: We describe the use of structured light plethysmography (SLP)-a novel, non-contact, light-based technique for measuring tidal breathing-among a cohort of patients undergoing lung resection. In this feasibility study, we examined whether changes in chest wall motion or in asynchrony between regions of the thoraco-abdominal wall could be identified after surgery.

Methods: Fifteen patients underwent wedge resection (n = 8) or lobectomy (n = 7). All patients underwent two SLP assessments (before surgery and on Day 1 post-surgery). Each assessment captured data during 5 min of quiet (tidal) breathing.

Results: When data were averaged across all patients, motion on the operated side of the thorax was significantly reduced after surgery (mean change from presurgery ± standard deviation: -14.7 ± 16.5%, P = 0.01), while motion on the non-operated side increased (15.9 ± 18.5%, P = 0.01). Thoraco-abdominal asynchrony also increased (mean change ± standard deviation: 43.4 ± 55.1%, P = 0.01), but no significant difference was observed in right-left hemi-thoracic asynchrony (163.7 ± 230.3%, P = 0.08). When analysed by resection type, lobectomy was associated with reduced and increased motion on the operated and non-operated side, respectively, and with an increase in both right-left hemi-thoracic and thoraco-abdominal asynchrony. No significant changes in motion or asynchrony were identified in patients who underwent wedge resection.

Conclusions: SLP was able to detect changes in chest wall motion and asynchrony after thoracic surgery. Changes in this small group of patients were consistent with the side of the incision and were most apparent in patients undergoing lobectomy.