Table 3.

Responses to limb dependency before (Pre) and during systemic sympathetic blockade (Post) (Protocol 2)

	Pre		Post

Limb position	Heart level	Limb dependent	Heart level	Limb dependent
*Young (n=5)*
Arm
Thoracic impedance, Ω	34.3±4.8	33.8±4.7	31.8±5.5^{^†}	31.4±5.3
HR, beats/min	49±3	50±3	48±3	49±3
Mean BP, mmHg	89±3	89±3	85±2^{^†}	85±1
Brachial MBV, cm/sec	1.6±0.4	1.3±0.4^*	1.2±0.3^{^†}	1.0±0.2^*
Brachial VR index, au	69±15	107±21^*	83±18	120±19^*
Skin flux, au	21.1±3.5	12.1±2.3^*	20.1±2.8	11.1±1.7^*
Skin VR index, au	4.7±0.8	10.8±2.1^*	4.6±0.7	11.0±2.1^*
Leg
Thoracic impedance, Ω	32.7±5.5	32.8±5.7	31.6±5.7^{^†}	31.8±5.8
HR, beats/min	51±4	51±4	49±3	50±3
Mean BP, mmHg	88±3	89±3	84±2^*	84±2
Popliteal MBV, cm/sec	1.2±0.2	0.8±0.1^*	1.2±0.2	0.8±0.1^*
Popliteal VR index, au	84±13	163±26^*	78±12	149±20^*
Skin flux, au	14.3±3.6	5.8±1.5^*	14.4±1.8	5.8±0.9^*
Skin VR index, au	7.9±1.9	23.5±4.6^*	6.1±0.6	19.9±2.3^*
*Older (n=5)*
Arm
Thoracic impedance, Ω	37.9±1.2	38.0±1.3	36.8±0.5^{^†}	36.9±0.7
HR, beats/min	58±3	58±4	55±2^{^†}	56±2^*
Mean BP, mmHg	94±3	94±2	85±3^{^†}	86±3
Brachial MBV, cm/sec	1.6±0.2	1.5±0.3	1.3±0.2	1.3±0.2
Brachial VR index, au	67±12	95±18^*	69±9	90±14^*
Skin flux, au	18.6±3.9	10.7±2.3^*	20.1±3.5	11.4±1.9^*
Skin VR index, au	6.8±2.3	16.5±6.9^*	4.9±1.0	11.5±3.0^*
Leg
Thoracic impedance, Ω	38.3±1.3	38.1±1.4	38.3±1.9	38.2±1.7
HR, beats/min	58±3	58±3	56±2^{^†}	57±2^*
Mean BP, mmHg	95±4	97±4	87±2^{^†}	87±3
Popliteal MBV, cm/sec	1.1±0.1	0.8±0.1^*	1.0±0.1	0.7±0.1^*
Popliteal VR index, au	90±14	162±21^*	91±11	154±15^*
Skin flux, au	11.2±3.0	5.3±1.5^*	11.7±1.8	5.8±1.1^*
Skin VR index, au	12.9±4.8	35.5±14.5^*	8.1±1.2	20.8±2.5^*

Values are mean±SE; HR=heart rate; BP=arterial pressure; MBV=mean blood velocity; VR=vascular resistance index (mean BP/MBV or flux); Mean BP was corrected to account for hydrostatic pressure effects (mean BP+(0.766^*30cm)) when the limb was dependent.

P<0.05 Δ from heart level

^†

P<0.05 compared to Pre (heart level)

^‡

compared to response in arm (same age group)