Table 1.
Mean values ± standard deviation of respiration, systolic and diastolic blood pressure, RR intervals, and time domain parameters of RRI variability in supine and standing positions in 20 patients with a history of mild TBI, 20 patients with a history of moderate or severe TBI (moderate–severe TBI) and 20 healthy controls
| Parameter | Position | Healthy controls (n = 20) | Mild-TBI patients (n = 20) | Moderate–severe TBI patients (n = 20) | Mild TBI vs. controls | Moderate–severe TBI vs. controls | Mild TBI vs. moderate–severe TBI |
|---|---|---|---|---|---|---|---|
| RESP (cpm) | Supine | 14.1 ± 3.1 | 14.6 ± 3.4 | 14.4 ± 2.6 | P = 0.391 | P = 0.545 | P = 0.736 |
| Standing | 14.5 ± 3.1 | 13.6 ± 4.1 | 13.4 ± 3.3 | P = 0.476 | P = 0.158 | P = 0.594 | |
| BPsys (mmHg) | Supine | 121.3 ± 15.2 | 122.5 ± 16.3 | 133.6 ± 14.2 | P = 0.821 | P = 0.012 | P = 0.027 |
| Standing | 136.2 ± 20.5 * | 136.9 ± 15.1 * | 138.6 ± 24.7 | P = 0.899 | P = 0.732 | P = 0.792 | |
| BPdia (mmHg) | Supine | 60.5 ± 8.0 | 61.7 ± 7.4 | 65.3 ± 10.2 | P = 0.616 | P = 0.107 | P = 0.214 |
| Standing | 72.3 ± 8.3 * | 70.5 ± 10.1 * | 73.3 ± 11.3 * | P = 0.542 | P = 0.754 | P = 0.418 | |
| RRI (ms) | Supine | 1041.0 ± 166.7 | 943.1 ± 123.5 | 1038.2 ± 203.3 | P = 0.052 | P = 0.962 | P = 0.144 |
| Standing | 801.0 ± 131.5 * | 775.6 ± 132.8 * | 790.4 ± 197.7 * | P = 0.547 | P = 0.843 | P = 0.783 | |
| RRI-SD (ms) | Supine | 59.4 ± 36.5 | 50.9 ± 27.0 | 49.5 ± 22.2 | P = 0.406 | P = 0.307 | P = 0.863 |
| Standing | 49.1 ± 25.4 | 39.4 ± 23.0 * | 41.3 ± 34.6 | P = 0.212 | P = 0.420 | P = 0.839 | |
| RRI-CV (%) | Supine | 5.7 ± 3.3 | 5.7 ± 3.3 | 4.7 ± 1.6 | P = 0.687 | P = 0.211 | P = 0.338 |
| Standing | 6.1 ± 2.8 | 4.9 ± 2.5 | 4.8 ± 3.0 | P = 0.149 | P = 0.171 | P = 0.943 | |
| RMSSD (ms) | Supine | 63.9 ± 40.3 | 47.1 ± 27.7 | 43.8 ± 25.2 | P = 0.131 | P = 0.065 | P = 0.697 |
| Standing | 24.8 ± 13.5 * | 23.2 ± 16.8 * | 28.2 ± 34.4 * | P = 0.747 | P = 0.680 | P = 0.562 | |
| RRI-30:15 ratio | Upon standing | 1.5 ± 0.3 | 1.4 ± 0.3 | 1.4 ± 0.4 | P = 0.166 | P = 0.288 | P = 0.879 |
RESP respiration, BPsys systolic blood pressure, BPdia diastolic blood pressure, RRI RR interval, SD standard deviation, CV coefficient of variance, RMSSD square-root-of-mean-squared-differences-of-successive-RRIs, cpm cycles per minute
An asterisk (*) indicates a significant difference (P < 0.05) between supine and standing values. Significant differences between groups are indicated in bold and underlined for the parameters, and in bold underlined italics for the P-values