Table 2.
Effect of source of feedback on effective compression depth
| Effective compression depth (mm) | Mean (95% confidence interval) | ||
|---|---|---|---|
| Source of feedback | |||
| Anterior sensor | Internal measure | Difference | |
| Typical mattress only | 37.8 (34.1, 41.5) | 52.1 (50.1, 54.1) | 14.3 (12.0, 16.5) |
| Typical mattress + backboard | 42.9 (39.5, 46.3) | 51.7 (49.8, 53.5) | 8.7 (6.5, 11.0) |
| Memory foam mattress only | 41.2 (37.9, 44.4) | 54.2 (52.3, 56.1) | 13.0 (10.7, 15.3) |
| Memory foam mattress + backboard | 46.3 (43.2, 49.3) | 53.7 (52.0, 55.5) | 7.5 (5.2, 9.8) |
Presented are the mean adjusted values from a mixed effects linear model. Fixed effect: mattress type, CPR backboard use, feedback source, interaction between feedback source and mattress type, and interaction between feedback source and CPR backboard use. Random effect: intercept, mattress type, CPR backboard use, and feedback source. Goodness of fit: marginal R 2 = 0.43, conventional R 2 = 0.80