Main cardiovascular and FOT parameters at baseline (room air) and neck suction at 0.1 and 0.2 Hz. For all conditions breathing frequency is 15 breaths•min-1.

RR interval: interval between two RR wave peaks; RR-SD: standard deviation of RR interval; SBP and DBP: systolic and diastolic pressures, respectively; SaO2: oxygen saturation; TO2I: Tissue Oxygen Index; R5 and R19, inspiratory resistance at 5 and 19 Hz, respectively; VT: tidal volume; V˙E: minute ventilation; CO2-ET: carbon dioxide end-tidal. Data are mean ± SD. RR0.1 Hz and RR0.2 Hz are expressed as natural logarithm of power spectra of RR interval at 0.1 and 0.2 Hz, respectively. t-test was used to compare RR0.1 between control and Neck suction (0.1 Hz), and to compare RR0.2 between control and Neck suction (0.2 Hz). ANOVA was used for all the other parameters that were compared for the three conditions.*: p¶: p§: pMain cardiovascular and FOT parameters at baseline (room air) and neck suction at 0.1 and 0.2 Hz. For all conditions breathing frequency is 15 breaths•min-1.