Table 5. Linear regression analysis of stress measures with hands-on time*.
| Parameter | Univariate regression coefficient (95%CI) | p-value | Multivariate regression coefficient (95%CI)** | p-value |
|---|---|---|---|---|
| Overall | ||||
| Heart rate | ||||
| Mean [/min] | -0.02 (-0.41, 0.37) | 0.924 | -0.03 (-0.44, 0.39) | 0.904 |
| Minimal [/min] | -0.18 (-0.71, 0.35) | 0.507 | -0.22 (-0.79, 0.36) | 0.459 |
| Maximal [/min] | -0.07 (-0.3, 0.17) | 0.580 | -0.08 (-0.33, 0.17) | 0.530 |
| Reactivity [/min] | -0.05 (-0.36, 0.25) | 0.739 | -0.06 (-0.38, 0.26) | 0.707 |
| Tachycardia [/100 sec] | 0.14 (-0.18, 0.46) | 0.384 | 0.14 (-0.19, 0.46) | 0.417 |
| Heart rate variability | ||||
| SDNN [ms], long-term HRV | 0.07 (-0.08, 0.22) | 0.365 | 0.08 (-0.08, 0.23) | 0.343 |
| RMSSD [ms], short-term HRV | 0.01 (-0.1, 0.13) | 0.805 | 0.02 (-0.11, 0.14) | 0.775 |
| ECG stress parameters | ||||
| All | -1.77 (-11.63, 8.09) | 0.723 | -1.53 (-11.73, 8.67) | 0.767 |
| ST-segment depression | 1.87 (-16.18, 19.91) | 0.838 | 2.53 (-16.04, 21.1) | 0.788 |
| ST-segment elevation | -63.11 (-110.90, -15.32) | 0.010 | -64.84 (-113.74, -15.93) | 0.010 |
| Inverted T-wave | -8.20 (-27.33, 10.90) | 0.397 | -8.39 (-27.89, 11.12) | 0.396 |
| Flattened T-wave | -6.87 (-17.46, 3.73) | 0.202 | -7.38 (-18.4, 3.64) | 0.187 |
| Biphasic T-wave | -14.8 (-49.73, 20.13) | 0.403 | -14.77 (-50.24, 20.7) | 0.411 |
| During resuscitation | ||||
| Heart rate | ||||
| Mean [/min] | 0.15 (-0.12, 0.42) | 0.269 | 0.14 (-0.14, 0.43) | 0.319 |
| Minimal [/min] | -0.05 (-0.37, 0.28) | 0.781 | -0.07 (-0.4, 0.27) | 0.701 |
| Maximal [/min] | 0.25 (0, 0.5) | 0.046 | 0.27 (-0.01, 0.54) | 0.055 |
| Reactivity [/min] | 0.7 (0.32, 1.07) | <0.001 | 0.82 (0.4, 1.24) | <0.001 |
| Tachycardia [/100 sec] | 7.04 (0.01, 14.07) | 0.050 | 7.3 (0, 14.6) | 0.050 |
| Heart rate variability | ||||
| SDNN [ms], long-term HRV | 0.1 (-0.02, 0.22) | 0.094 | 0.1 (-0.02, 0.22) | 0.101 |
| RMSSD [ms], short-term HRV | 0.04 (-0.07, 0.14) | 0.474 | 0.04 (-0.07, 0.15) | 0.477 |
*hands-on time during the first 180 seconds after start of CPR
**adjusted for gender, chest compression and leadership designation
CPR: Cardiopulmonary resuscitation; HRV: Heart rate variability; SDNN: Standard deviation of all normal to normal intervals; RMSSD: Root-mean-square of successive differences; ms: Milliseconds; Before resuscitation: 10min before cardiac arrest; During resuscitation: Duration of cardiac arrest; After resuscitation: 30min after cardiac arrest; Tachycardia: HR >100bpm, ECG: Electrocardiogram