Fig. 2
From: Kinematic signature of high risk labored breathing revealed by novel signal analysis
Relative movements of the chest and abdomen. This figure illustrates the information contained in the amplitude-relationships between the kinematic signals by displaying the signals of three patients (rows 1–3) whose breathing pattern varied in this regard. The first column of panels (A1-A3) shows one accelerometer signal from the lower rib (blue) and abdominal (orange) sensor of each patient. The instantaneous amplitude series of the signals in A1-A3 is plotted in panels B1-B3 respectively. Panels C1-C3 show the amplitude ratio series that is obtained by dividing the lower rib amplitude series by the abdominal amplitude series in B1-B3. The first patient (Row 1) has a stable phenotype of rib-predominant breathing: the lower rib sensor (blue) has a higher amplitude kinematic signal than the abdominal sensor (orange) in A1; the lower rib (blue) has higher instantaneous amplitude than the abdomen (orange) in B1; and the amplitude ratio series in C1 has a mean value greater than 1. In contrast to the rib-predominant breathing of the first patient, the second patient (Row 2) has abdomen-predominant breathing (A2 and B2) which results in an amplitude ratio that is less than 1 (C2). Despite their different breathing patterns, both of these patients have a stable pattern from one breath to the next. As a result, their amplitude ratio time series (C1 and C2) have low variability. In contrast, the third patient (row 3) has an unstable breathing pattern where rib predominant breaths alternate with abdomen predominant ones. This results in an amplitude ratio time series (C3) with high variability. Panel D schematically represents the derivation of our measures for respiratory alternans and recruitment of accessory muscle.
