Table 1. Unique, mutually-exclusive patterns of respiratory inductive plethysmography and their scoring rules.
| Pattern | Definition | Scoring Rule | Example |
|---|---|---|---|
| Synchronous-breathing (SYB) | Quasi-sinusoidal breathing patterns in RCG and ABD, where the inspiration and expiration movements of RCG and ABD are in phase. | Phase difference of less than 90°. | Fig 3 |
| Asynchronous-breathing (ASB) | Quasi-sinusoidal breathing patterns in RCG and ABD, where the RCG and ABD movements are out of phase. | Phase difference of 90° or more. | Fig 4 |
| Sigh (SIH) | A breath with considerably larger amplitude and duration than preceding breaths. | Breath amplitude and duration twice that of the epoch’s average breath in both RCG and ABD. | Fig 5 |
| Movement artifact (MVT) | A period during which both RCG and ABD signals are corrupted by movements not related to respiration. | RCG and ABD display a chaotic, non-sinusoidal, low frequency motion. | Fig 6 |
| Respiratory pause (PAU) | A period where respiratory movements are absent in both RCG and ABD. | RCG and ABD have amplitudes less that 10% of those of the preceding normal breath. A PAU begins at the start of inspiration of the first breath that is clearly reduced, and ends with the start of inspiration of the first breath whose amplitude returns to the epoch’s average breath amplitude. If the start or end time of a PAU differs between RCG and ABD, the priority is given to the signal with higher SNR. All respiratory pauses are scored regardless of duration. Special cases: | Fig 1 |
| (i) PAU following SIH: RCG and ABD have amplitudes of less than 10% of that of the breath preceding the sigh in both signals. | Fig 7 | ||
| (ii) PAU following MVT: RCG and ABD have amplitudes of less than 10% of that of the breath that follows the pause in both signals. | Fig 8 | ||
| Unknown (UNK) | Any other pattern arising from technical problems (e.g., loss of a connector, high noise), or ambiguous patterns (e.g., MVT during SYB, different patterns in RCG and ABD). | RCG and/or ABD do not correspond to any other pattern. | Fig 9 |
RCG = ribcage, ABD = abdomen, SNR = signal-to-noise ratio.