Table 2.
Statistical Results of the Linear Mixed Model and Generalized Linear Mixed Model Analysis
| Variable | P value | |||
|---|---|---|---|---|
| Angle | Position* | Angle × position | Supine vs prone † | |
| Hemodynamic measurements | ||||
| HR | <0.001 ‡ | <0.001 ‡ | 0.609 | <0.001 ‡ |
| SV | <0.001 ‡ | <0.001 ‡ | 0.157 | <0.001 ‡ |
| CO | <0.001 ‡ | <0.001 ‡ | 0.266 | 0.048 § |
| TPR | <0.001 ‡ | <0.001 ‡ | 0.834 | 0.024 § |
| SBP | 0.005 ‖ | 0.251 | 0.645 | … |
| DBP | <0.001 ‡ | 0.003 ‖ | 0.997 | 0.172 |
| RPP | <0.001 ‡ | <0.001 ‡ | 0.308 | <0.001 ‡ |
| VO2 | 0.244 | <0.001 ‡ | 0.915 | <0.001 ‡ |
| Time‐domain autonomic indices | ||||
| SDNN | <0.001 ‡ | 0.214 | 0.656 | … |
| RMSSD | <0.001 ‡ | 0.002 ‖ | 0.789 | <0.001 ‡ |
| HRVTi | <0.001 ‡ | 0.710 | 0.555 | … |
| BRS | <0.001 ‡ | <0.001 ‡ | 0.386 | 0.066 |
| Frequency‐domain autonomic indices | ||||
| LF | <0.001 ‡ | 0.106 | 0.776 | … |
| HF | <0.001 ‡ | 0.250 | 0.515 | … |
| LFNorm | <0.001 ‡ | 0.745 | 0.615 | … |
| HFNorm | <0.001 ‡ | 0.746 | 0.615 | … |
| LF/HF | <0.001 ‡ | 0.300 | 0.084 | … |
Fixed factors included Angle, Position, and their interaction. Subjects were included as random factors. See text for model details. BRS, baroreflex sensitivity; CO, cardiac output; DBP, diastolic blood pressure; HF, high frequency; HFNorm, normalized high frequency; HR, heart rate; HRVTi, heart rate variability triangular index; LF, low frequency; LFNorm, normalized low frequency; RMSSD, , root mean square of successive differences of NN intervals; RPP, rate pressure product; SBP, systolic blood pressure; SDNN, standard deviation of NN intervals; SV, stroke volume, TPR, total peripheral resistance; and VO2, oxygen consumption.
Main effect of Position includes seated baseline.
Post hoc contrast to determine whether there is a true difference between supine and prone positions (ie, does not include seated baseline).
P<0.001.
P<0.05.
P<0.01.