Table 1.
Description of measures from the hyperventilation (HV) challenge and MyCalmBeat assessments
| Measure | Description | Units |
|---|---|---|
| Baseline HR and respiratory rate | ||
| Clinical baseline breathing rate | The baseline breathing rate collected during the MyCalmBeat assessment | Breath per minute |
| Baseline HR | The baseline HR value from the start of the HV challenge (zero value on Fig. 1) | bpm |
| Hyperventilation challenge PCO2 measures | ||
| Baseline PCO2 | The baseline PCO2 value from the start of HV challenge (zero value on Fig. 1) | mmHg |
| ∆PCO2 | Change in PCO2—the size of the PCO2 drop—calculated as HV baseline PCO2 minus lowest PCO2 level during HV challenge | mmHg |
| Trough PCO2 | Lowest PCO2 value during HV challenge | mmHg |
| Time to trough PCO2 | Time from HV baseline PCO2 (zero value) to trough-PCO2 value | minutes |
| Rate of PCO2 drop | Rate of drop from HV baseline PCO2 (zero value) to trough-PCO2 value | mmHg/min |
| Rate of PCO2 recovery | Rate of elevation of PCO2 from trough-PCO2 value during recovery period was calculated from trough-PCO2 value during HV challenge to first value in the homeostatic range (≥36 mmHg) (if homeostasis was attained) trough-PCO2 value during HV challenge to final PCO2 value after termination of HV challenge and 15 min of recovery (if homeostasis was not attained) | mmHg/min |
| Final PCO2 | Final PCO2 reading after termination of HV challenge and 15 min of recovery | mmHg |
| Other terms used | ||
| Skewed HV profile | A HV profile that was shifted down and defined by baseline PCO2 < 36 mmHg, trough-PCO2 ≤ 20 mmHg, or final PCO2 < 36 mmHg baseline | |