Table 2 Validation and agreement statistics (with 95% confidence intervals) for the LifeShirt system during day & night and at low & high respiration rates. Values are calculated values for the sensitivity (SN), specificity (SP), positive predictive-value (PPV), negative predictive-value (NPV), accuracy (ACC) and the kappa statistic. Values in parentheses are the 95% confidence intervals. All values are for LS system compared to video documentation of cough events; * p-value < 0.0001 for night vs. day comparisons of period for SN, SP, NPV and ACC; ¶p-value < 0.0001 for night vs. day comparisons of respiratory rate for SN, SP, PPV, NPV; ‡ p-value = 0.004 for day vs. night comparisons of respiratory rate for ACC. Day period defined as 0600–1800; Night period defined as 1800–0600. Patients were assigned to the low or high respiratory rate group based on whether their mean Fb was below or above the median Fb (median = 21 br·min-1).
Period | Respiratory Rate | ||||
|---|---|---|---|---|---|
Combined | Day | Night | Low | High | |
SN | 78.1 (76.7, 79.4) | 76.7 (75.1, 78.2) | 82.7 (80.0, 85.1)* | 69.5 (66.3, 72.6) | 80.6 (79.0, 82.0)¶ |
SP | 99.6 (99.5, 99.6) | 99.6 (99.5, 99.6) | 99.7 (99.7, 99.8)* | 99.5 (99.5, 99.6) | 99.7 (99.6, 99.7) ¶ |
PPV | 84.6 (83.3, 85.8) | 84.5 (83.0, 85.8) | 85.0 (82.3, 87.3) | 69.8 (66.5, 72.8) | 89.4 (88.1, 90.5) ¶ |
NPV | 99.4 (99.3, 99.4) | 99.3 (99.2, 99.3) | 99.7 (99.6, 99.7)* | 99.5 (99.5, 99.6) | 99.3 (99.2, 99.3) ¶ |
ACC | 99.0 (99.0, 99.1) | 98.8 (98.8, 98.9) | 99.4 (99.3, 99.5)* | 99.1 (99.0, 99.2) | 99.0 (98.9, 99.0)‡ |
Kappa | 80.7 (79.7, 81.7) | 79.8 (78.6, 81.0) | 83.5 (81.5, 85.5) | 69.2 (66.6, 71.7) | 84.2 (83.1, 85.3) |