Structured light plethysmography measures asynchronous breathing patterns in patients with acute stroke

Abstract

Background: The extent of respiratory compromise following a stroke depends on any pre-existing respiratory illness and the aetiology, location and extent of the lesion. Acquired respiratory infection in subsequent days may alter respiratory function. Structured Light Plethysmography (SLP) is a non-contact, non-invasive technique that measures chest and abdominal wall movement to provide objective indices of tidal breathing. By comparing the relative contribution of chest and abdomen excursions as well as right chest and left chest movement, it is possible to measure and monitor asynchronous breathing in these patients. Methods: We recruited 10 patients [5 male, mean age 71.7 years (SD±20.1)] within 10-48 hours of admission with an acute stroke to the Royal Stoke University Hospital. These patients are the initial cohort of a larger longitudinal observation study using SLP in this population. Bedside measurements lasting up to 5 minutes were made on each patient using a Thora-3Di TM device (PneumaCare Ltd, Cambridge, UK) and tidal breathing parameters were derived from the analysis of chest wall movement. Results: Tidal breathing parameters: respiratory rate 20.3±6 (mean±SD) in minutes, time to inspiration (Ti) 1.3±0.4, and time to expiration (Te) 1.9±0.4 in seconds. Asynchrony was observed in three patients who developed pneumonia on admission with a percent of relative contribution of chest wall on the affected side of 35%, 42% and 46%. Asynchrony was also observed in another 2 patients without pneumonia with a relative contribution of 22% and 42%. Conclusion: This is the first study using SLP to detect and characterize respiratory dysfunction in acute stroke patients.