Table 1.
Effect of backboard use and memory foam on mattress compression depth
| Mattress compression depth (mm) | Mean (95% confidence interval) | |||
|---|---|---|---|---|
| No backboard | Backboard | Backboard benefit | Backboard mean benefit main effect | |
| Typical mattress | 47.9 (40.5, 55.3) | 34.6 (28.6, 40.7) | 13.3 (10.6, 15.9) | 11.6 (9.0, 14.3) |
| Memory foam | 34.6 (28.6, 40.7) | 24.6 (22.5, 26.7) | 10.0 (7.4, 12.7) | |
| Memory foam benefit | 13.3 (6.4, 20.2) | 10.0 (3.2, 16.9) | NA | NA |
| Memory foam mean benefit main effect | 11.7 (4.8, 18.5) | NA | NA | |
Presented are the mean adjusted values from a mixed effects linear model. Fixed effect: mattress type, use of CPR backboard and interaction between mattress type and use of CPR backboard. Random effect: intercept, mattress type, and use of CPR backboard. Goodness of fit: marginal R 2 = 0.33, conventional R 2 = 0.82
NA not applicable